A method for monitoring deterioration of kiwifruit during storage based on gas composition analysis

Abstract

The application discloses a kiwi fruit storage period deterioration monitoring method based on gas component analysis, and particularly relates to the field of kiwi fruit storage period deterioration monitoring, which comprises the following steps: introducing a mixed gas flow path into a kiwi fruit storage space, guiding the mixed gas into the entrance of an electric field trapping cavity, and keeping the mixed gas entering the electric field trapping cavity in the original component proportion of the storage space; applying a preset electric potential in the electric field trapping cavity, forming a trapping area of polar molecules in the electric field trapping cavity, and adsorbing the deterioration precursor gas in the mixed gas in the trapping area to form an enrichment structure corresponding to the adsorption time. Through the electric field trapping and spatial enrichment of the extremely low concentration of the deterioration precursor gas in the mixed gas, and then inputting the enriched high local concentration gas into a tunable laser absorption link to realize the explicitness of the weak signal, the problem that trace precursor gas characteristic signals cannot be separated in a wide absorption background in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of kiwifruit deterioration monitoring technology during storage, and more specifically, to a method for monitoring kiwifruit deterioration during storage based on gas composition analysis. Background Technology

[0002] In the cold storage of kiwifruit, the most likely gases to accumulate in the air are conventional gases such as carbon dioxide and ethanol, which have relatively high concentrations. However, the gases that truly reflect early signs of deterioration, such as very small amounts of certain sulfur-smelling molecules or nitrile molecules, are often several orders of magnitude lower in concentration. Existing tunable laser gas analysis technology scans the absorption of gases at different wavelengths. Theoretically, it can find the absorption characteristics of these precursor gases in specific bands. However, in real environments, high concentrations of carbon dioxide and ethanol also have relatively broad absorption curves in adjacent or even the same bands, which will form a large area of ​​slowly fluctuating absorption background in the spectrum. The signal of trace precursor gases is already very weak. When superimposed on such an absorption background, it will be completely covered by the elongated absorption curve of the main component. The measured result will only appear to follow the slight changes of the main component, and it will be difficult to identify the independent small peaks. Even when operators use higher resolution spectrometers, extend the integration time, and repeatedly perform background subtraction, what they still see is a large shape dominated by the principal component, as if the precursor gas does not exist at all. As a result, the detection system in the cold storage was in a state where it could only see the bulk gases and not the key trace gases for a long time. When early deterioration had already begun, the monitoring results still showed that everything was normal. The core problem is that in the current storage environment of multi-component mixed gases, the tunable laser spectrum is dominated by the broad absorption curve of high-concentration conventional gases, making it impossible to separate the independent characteristic signals of extremely low-concentration precursor gases, resulting in the early deterioration of kiwifruit remaining undetected for a long time. Summary of the Invention

[0003] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis. This method utilizes an intelligent sensing system to first perform electric field trapping and spatial enrichment on extremely low concentrations of precursor gases in a mixed gas mixture. Then, the enriched gas with high local concentrations is input into a tunable laser absorption link, and edge computing is combined to perform real-time analysis of the absorption data, thereby making weak signals explicit. This addresses the problem mentioned in the background art of being unable to separate trace precursor gas characteristic signals under a wide absorption background.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis, comprising: S1. Introduce a flow path for mixed gas in the kiwi fruit storage space and guide the mixed gas into the inlet of the electric field trapping cavity, so that the mixed gas entering the electric field trapping cavity maintains the original component ratio of the storage space. S2. Apply a preset potential inside the electric field trapping cavity to form a trapping region for polar molecules inside the electric field trapping cavity, and adsorb the deterioration precursor gas in the mixed gas in the trapping region to form an enrichment structure corresponding to the adsorption time. S3. After the enrichment structure reaches the preset output conditions, the potential control of the trapping region is released, and the enriched gas in the enrichment structure is output through the gas outlet of the electric field trapping cavity, so that the output gas forms a concentration output stream. S4. Introduce the concentration output stream into the detection optical path, and use a tunable laser to form a continuous wavelength scan in the detection optical path. Record the absorption changes of the corresponding band during the scan to generate an absorption data sequence covering the target absorption range. S5. Identify the presence of precursor gases based on the absorption data sequence, and determine the deterioration risk status of the kiwifruit storage space based on the identification results.

[0005] In a preferred embodiment, S1 includes: S1-1. In the kiwifruit storage space, the mixed gas released by the kiwifruit collectively is collected and defined as the input gas entering the subsequent processing structure; the mixed gas includes carbon dioxide and ethanol. S1-2. Construct a flow path structure consisting of a flow path inlet, a flow path channel, and an electric field trapping cavity connected to the flow path channel. The electric field trapping cavity consists of a cavity shell, an internal electrode assembly, a gas inlet, and a gas outlet, and is used to perform electric field trapping operations on the mixed gas. S1-3. After the mixed gas enters the flow path structure, the flow state of the mixed gas in the flow path channel is controlled so that the mixed gas maintains the same component ratio as the kiwi fruit storage space without component separation, and the mixed gas with the same component ratio is guided to the gas inlet of the electric field trapping cavity. S1-4. After the mixed gas enters the gas inlet of the electric field trapping cavity, the mixed gas is driven by flow to form the input structure of the gas to be trapped inside the electric field trapping cavity.

[0006] In a preferred embodiment, S2 includes: S2-1. Two conductive electrode plates are arranged opposite each other in the internal electrode assembly of the electric field trapping cavity. The conductive electrode plate near the mixed gas inlet is defined as the first electrode plate, and the conductive electrode plate arranged opposite to the first electrode plate is defined as the second electrode plate. The first electrode plate is connected to the positive terminal of the power supply, and the second electrode plate is connected to the negative terminal of the power supply, so as to construct a directional electric field in the trapping region between the first electrode plate and the second electrode plate. S2-2. Perform polarity determination on each molecule in the mixed gas entering the electric field trapping cavity, define molecules with dipole moments as polar molecules, and calculate the migration speed and displacement of polar molecules based on the electric field strength and the dipole moments of polar molecules under the action of the directional electric field. Converge polar molecules whose displacement reaches the preset migration threshold to the local space near the second electrode plate. S2-3. Count the number of polar molecules in the local space near the second electrode plate, and perform aggregation completion judgment based on the relationship between the number of polar molecules per unit volume and the upper limit of compression density. Mark the local space where the number of polar molecules per unit volume reaches the preset upper limit of compression density as a trap. Perform adsorption time timing on the trap and mark the trap where the adsorption time reaches the preset upper limit of adsorption time as the enriched structure corresponding to the adsorption time.

[0007] In a preferred embodiment, S3 includes: S3-1. After the enriched structure is formed, the output condition is determined: the number of polar molecules in the local space of the trapped body is calculated and the unit volume density is obtained. The unit volume density is compared with the preset upper limit of the compressibility density. At the same time, the adsorption time is timed and the timed result is compared with the upper limit of the adsorption time. When both comparison results meet the upper limit conditions, it is determined that the enriched structure has reached the preset output condition. Otherwise, the density statistics and adsorption time timing are continued. S3-2. After determining that the enrichment structure has reached the preset output condition, disconnect the potential connection between the first electrode plate and the second electrode plate. By making the potential of the two electrode plates return to the zero potential position of the power supply at the same time, the directional electric field that originally limited the polar molecules disappears, and the polar molecules in the captured state in the enrichment structure are no longer bound by the electric field. S3-3. After removing the directional electric field, a flow drive is applied inside the electric field trapping cavity. By establishing a constant pressure difference between the gas inlet and the gas outlet, the polar molecules in the enriched structure are continuously displaced along the gas outlet direction.

[0008] In a preferred embodiment, S3 further includes: S3-4. When the enrichment structure is shifted to the gas outlet, the flow rate of the polar molecules moving out is integrated and synchronized. By combining the instantaneous flow rate at the outlet with the instantaneous density of molecules on the outlet cross section, a continuously changing concentration distribution is constructed and a concentration output flow is formed. If the instantaneous density at the outlet does not meet the preset continuous output requirement, the flow drive is continuously executed until a continuous concentration output flow is formed.

[0009] In a preferred embodiment, S4 includes: S4-1. After the concentration output flow reaches the optical detection position, the detection optical path is constructed into a continuous transmission chain by sequentially forming the incident optical path, the gas absorption path, and the exit optical path. The optical path filling calculation is performed on the gas absorption path: the real-time flow rate is obtained by monitoring the pressure difference between the inlet and outlet of the gas absorption path, and then the real-time filling ratio of the absorption path is calculated by converting the real-time flow rate, and the real-time filling ratio is compared with the full-load filling ratio. If the comparison results are consistent, proceed to the next execution step; otherwise, adjust the flow rate drive until the two are consistent. S4-2. At the incident end of the detection optical path, the tunable laser is used as the input source and wavelength scanning configuration is performed on its internal tuning chain: First, the minimum and maximum scanning wavelengths are calculated based on the target absorption range. Then, the feedback error of the frequency controller is used as the adjustment reference, and the continuously changing output wavelength is obtained by adjusting the effective length of the resonant cavity. The output power is calculated at each wavelength point and compared with the lower power limit. If the output power is lower than the lower power limit, the resonant cavity compensation amount is recalculated and compensation adjustment is performed. Otherwise, the wavelength scanning continues. S4-3. After the tunable laser completes continuous scanning configuration, the laser beam passes through the gas absorption path completely filled by the concentration output stream, and the absorption is calculated for each scanning wavelength: the incident light intensity and the output light intensity are obtained sequentially, and the difference between the two is taken as the absorption of that wavelength; at the same time, the stability of the absorption is judged. When the light intensity difference falls into the stable range, the absorption is recorded. Otherwise, the wavelength is scanned repeatedly and the average value of the repeated scans is taken as the final absorption.

[0010] In a preferred embodiment, S4 further includes: S4-4. After obtaining the absorption amount covering the entire scanning range, construct each absorption amount into a data chain arranged with a fixed step size according to the scanning order, and perform a step size consistency check on the data chain: calculate the actual step size between any adjacent wavelength points and compare it with the upper limit of step size deviation. When all step sizes meet the deviation requirements, define the data chain as an absorption data sequence; if there are wavelength segments that exceed the upper limit of deviation, perform interpolation correction to fill in the missing wavelength points, and then define the corrected data chain as an absorption data sequence covering the target absorption range.

[0011] In a preferred embodiment, S5 includes: S5-1. For each preset precursor gas of deterioration, read the three absorbance values ​​corresponding to its main absorption peak wavelength, front shoulder peak wavelength, and rear shoulder peak wavelength from the absorption data sequence. Then, perform a weighted summation of the three absorbance values ​​according to the pre-calibrated center peak weighting coefficient, front shoulder peak weighting coefficient, and rear shoulder peak weighting coefficient, and add a preset offset to calculate the instantaneous concentration of the gas. If any one of the three absorbance values ​​is missing, the instantaneous concentration of the gas is recorded as zero. S5-2. Perform an existence quantity judgment on the instantaneous concentration of each precursor gas of degradation. Compare the instantaneous concentration with the lower limit and upper limit of the existence quantity of the precursor gas of degradation. When the instantaneous concentration is greater than or equal to the lower limit and less than or equal to the upper limit, the instantaneous concentration is taken as the effective existence quantity of the precursor gas of degradation. Otherwise, the effective existence quantity of the precursor gas of degradation is recorded as zero, and the effective existence quantities of all precursor gases of degradation are combined into an existence quantity vector.

[0012] In a preferred embodiment, S5 further includes: S5-3. Perform degradation risk calculation on the existence vector. Multiply the effective existence quantity of each degradation precursor gas in the existence vector with the corresponding preset risk coefficient and sum them to obtain the degradation risk value. Compare the degradation risk value with the preset first risk threshold and second risk threshold. When the degradation risk value is less than the first risk threshold, the kiwifruit storage space is calculated as the first degradation risk state. When the degradation risk value is greater than or equal to the first risk threshold and less than the second risk threshold, the kiwifruit storage space is calculated as the second degradation risk state. When the degradation risk value is greater than or equal to the second risk threshold, the kiwifruit storage space is calculated as the third degradation risk state.

[0013] The technical effects and advantages of this invention are as follows: 1. This scheme introduces an electric field trapping cavity before tunable laser detection, which actively migrates, aggregates and forms enriched structures from high-concentration carbon dioxide and ethanol to extremely low concentrations of precursor gases of degradation. This increases the local density of trace small molecules before they enter the absorption optical path, eliminates the sinking effect of the broad absorption background on weak absorption peaks, and prevents early degradation characteristics from being covered by the main component absorption curve, thereby enabling the identifiable detection of key precursor gases.

[0014] 2. In this scheme, the enrichment conditions are defined in the electric field trapping cavity by a sequential link of "polarity determination - migration calculation - compression density threshold judgment". This makes the enriched structure deterministic in terms of spatial location, number of molecules and adsorption time. Its essence is to establish a stable spatial amplification mechanism through calculable electric field dynamics. Therefore, the gas entering the optical detection stage has uniform enrichment characteristics, reducing the random fluctuation of absorption data.

[0015] 3. This scheme applies a constant pressure difference after the potential is released, so that the enriched structure is continuously ejected in the form of a whole molecular group, and a time-consistent concentration output stream is formed at the outlet. This output stream maintains the original density distribution of the enriched structure, so that the optical absorption path obtains a stable and repeatable concentration input at each wavelength scan, thereby improving the spectral comparability and signal consistency between multiple scans.

[0016] 4. In the optical detection stage, this scheme constructs a quantitative link by “fill ratio calibration - continuous scanning compensation - three-wavelength weighted inversion - risk vector calculation”, so that the conversion from instantaneous absorption to gas presence and then to deterioration risk value has a clear numerical basis. It can also maintain the reconfigurability of the algorithm under different batches, different storage temperatures and different gas extraction conditions, so that the monitoring results can be transformed from empirical judgment to quantifiable decision-making. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0018] Figure 2 This is a schematic diagram of the flow path structure of the present invention.

[0019] Figure 3 This is a schematic diagram of the electric field trapping cavity of the present invention.

[0020] Figure 4 This is a schematic diagram of the internal electrode assembly of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Refer to the instruction manual appendix Figure 1-4 An embodiment of the present invention provides a method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis, comprising: S1. Introduce a flow path for mixed gas in the kiwi fruit storage space and guide the mixed gas into the inlet of the electric field trapping cavity, so that the mixed gas entering the electric field trapping cavity maintains the original component ratio of the storage space. S2. Apply a preset potential inside the electric field trapping cavity to form a trapping region for polar molecules inside the electric field trapping cavity, and adsorb the deterioration precursor gas in the mixed gas in the trapping region to form an enrichment structure corresponding to the adsorption time. S3. After the enrichment structure reaches the preset output conditions, the potential control of the trapping region is released, and the enriched gas in the enrichment structure is output through the gas outlet of the electric field trapping cavity, so that the output gas forms a concentration output stream. S4. Introduce the concentration output stream into the detection optical path, and use a tunable laser to form a continuous wavelength scan in the detection optical path. Record the absorption changes of the corresponding band during the scan to generate an absorption data sequence covering the target absorption range. S5. Identify the presence of precursor gases based on the absorption data sequence, and determine the deterioration risk status of the kiwifruit storage space based on the identification results.

[0023] S1 includes: S1-1. In the kiwifruit storage space, the mixed gas released by the kiwifruit collectively is collected and defined as the input gas entering the subsequent processing structure; the mixed gas includes carbon dioxide, ethanol and other gases that indicate deterioration. S1-2. Construct a flow path structure consisting of a flow path inlet, a flow path channel, and an electric field trapping cavity connected to the flow path channel. The electric field trapping cavity consists of a cavity shell, an internal electrode assembly, a gas inlet, and a gas outlet, and is used to perform electric field trapping operations on the mixed gas in subsequent steps. The electric field trapping cavity can be understood as a small, sealed cavity with an internal electrode plate. Its exterior is connected to the flow path of the mixed gas through a gas inlet and to the subsequent detection optical path through a gas outlet. When the mixed gas enters the cavity, the electrode plate forms a stable electric field after being energized, causing molecules with specific polarities to be briefly adsorbed and concentrated. After the set adsorption time is reached, the cavity then transports these concentrated gases from the gas outlet to the subsequent detection structure, thereby achieving the enrichment and output of gases that are precursors to deterioration. Furthermore, the internal electrode assembly of the electric field trapping cavity consists of one or more pairs of conductive electrode plates fixed inside the cavity. Each electrode plate is connected to the positive and negative terminals of an external power supply, respectively, and is directly introduced into the potential control port outside the cavity through wires. The electrode plates are made of a metal material that can conduct electricity stably and are kept insulated from the inner wall of the cavity so as to form a stable electric field inside the cavity after energization to trap polar molecules in the mixed gas. The flow path structure can be understood as a continuous channel that stably delivers the mixed gas from the inlet to the electric field trapping cavity. It consists of an inlet for the gas to enter, a channel for transporting the gas, and an electric field trapping cavity directly connected to the channel. After the mixed gas enters from the inlet, it moves forward along the channel and is delivered to the electric field trapping cavity without being separated or altered, ensuring that the subsequent trapping steps obtain a stable input gas. S1-3. After the mixed gas enters the flow path structure, the flow state of the mixed gas in the flow path channel is controlled so that the mixed gas maintains the same component ratio as the kiwi fruit storage space without component separation, and the mixed gas with the same component ratio is guided to the gas inlet of the electric field trapping cavity. In S1-3, it should be noted that: for the movement of the mixed gas within the flow path structure, the flow state of the mixed gas in the flow path channel needs to be directly controlled to prevent component separation during movement and maintain the component ratio consistent with the kiwi fruit storage space; the mixed gas consists of carbon dioxide, ethanol, and a precursor gas of deterioration, and these three need to move simultaneously in the flow path channel as a whole gas. Therefore, the flow state is a combination of flow velocity, flow direction, and fluid pressure; flow velocity is used to specify the speed at which the mixed gas moves forward in the flow path channel; flow direction is used to ensure that the mixed gas moves along the axial direction of the channel; and fluid pressure is used to maintain the uniform distribution of the mixed gas across the channel cross-section. By maintaining the flow rate between a set upper and lower limit, keeping the flow direction unidirectional along the channel axis, and keeping the pressure within a stable pressure range in the flow path channel, the mixed gas can move synchronously as a whole within the channel, thereby avoiding spatial stratification or concentration shift of carbon dioxide, ethanol, or precursor gases of deterioration due to velocity or pressure differences. By maintaining the above-mentioned flow rate, flow direction, and pressure in a continuous and stable state, the component ratio of the mixed gas can remain consistent with that of the storage space after entering the flow path structure from the storage space. While maintaining this consistent component ratio, the mixed gas is pushed along the flow path channel to the gas inlet of the electric field trapping chamber, providing accurate input for subsequent trapping steps. S1-4. After the mixed gas enters the gas inlet of the electric field trapping cavity, the mixed gas is driven by flow to form an input structure for the gas to be trapped inside the electric field trapping cavity, and this input structure is used as the input source for subsequent trapping steps. In S1-4, it should be noted that: for the movement process of the mixed gas after entering the electric field trapping cavity from the flow path channel, it is necessary to apply flow drive to the mixed gas to form an input structure for the gas to be trapped inside the electric field trapping cavity; the flow drive is achieved by building a stable pressure difference between the gas inlet and the gas outlet of the electric field trapping cavity. The pressure difference is used to push the mixed gas to move in a single direction inside the cavity, so that the mixed gas forms a continuous and stable flow path inside the cavity; through the above flow path, the mixed gas can be distributed sequentially in the gas inlet region, the internal gas channel region, and the region where the internal electrode assembly is located inside the electric field trapping cavity, thereby forming the input structure for the gas to be trapped; The input structure represents the input state of the mixed gas inside the electric field trapping cavity for subsequent trapping operations. Specifically, the input structure includes the following: the entry state of the mixed gas in the gas inlet region, the continuous flow state of the mixed gas in the internal channel of the cavity, and the trappable state of the mixed gas in the internal electrode assembly region. By maintaining the continuous connection of the above three states in the input structure, the mixed gas can reach the region where the internal electrode assembly is located in a stable form, providing an accurate input source for subsequent trapping steps.

[0024] In S2, the steps of applying a preset potential within the electric field trapping cavity and forming an enriched structure include: S2-1. Two conductive electrode plates are arranged opposite each other in the internal electrode assembly of the electric field trapping cavity. The conductive electrode plate near the mixed gas inlet is defined as the first electrode plate, and the conductive electrode plate arranged opposite to the first electrode plate is defined as the second electrode plate. The first electrode plate is connected to the positive terminal of the power supply, and the second electrode plate is connected to the negative terminal of the power supply, so as to construct a directional electric field in the trapping region between the first electrode plate and the second electrode plate. This arrangement is designed to immediately establish an electric field surface at the first contact point after the mixed gas enters the electric field trapping cavity, so that polar molecules are directionally driven in the initial region of entering the cavity. At the same time, by connecting the two conductive electrode plates in opposite positions to the positive and negative terminals of the power supply, a stable potential difference can be formed between the two electrode plates, and a unidirectional directional electric field can be generated inside the cavity, thereby providing a unified driving force field for the subsequent migration, displacement and aggregation of polar molecules. S2-2. Polarity determination is performed on each molecule in the mixed gas entering the electric field trapping cavity. Molecules with dipole moments are defined as polar molecules. Under the action of a directional electric field, the migration velocity and displacement of polar molecules are calculated based on the electric field strength and the dipole moment of the polar molecules. Polar molecules whose displacement reaches a preset migration threshold are gathered into the local space near the second electrode plate. Secondly, this determination is because only molecules with dipole moments in the mixed gas will produce a calculable electric field response in the directional electric field. Their force direction, migration velocity, and displacement can all be determined based on the electric field strength and dipole moment. Molecules without dipole moments will not form a stable orientation or be subjected to force in the electric field and cannot generate a displacement difference through the electric field. Therefore, only performing polarity determination and calculating migration velocity and displacement on molecules with dipole moments can ensure that the molecules finally gathered near the second electrode plate are indeed target objects that can undergo directional migration according to the electric field law. S2-3. Count the number of polar molecules in the local space near the second electrode plate, and perform an aggregation completion judgment based on the relationship between the number of polar molecules per unit volume and the upper limit of the compression density. Mark the local space where the number of polar molecules per unit volume reaches the preset upper limit of the compression density as a trapped body. Perform adsorption time timing on the trapped body, and mark the trapped body where the adsorption time reaches the preset upper limit of the adsorption time as an enriched structure corresponding to the adsorption time. Use the enriched structure as the input source for subsequent output steps. The trapped body is essentially a concentrated region of polar molecules that accumulates to the upper limit of the compression density in the local space near the second electrode plate, driven by the continuous migration of the directional electric field. It is composed of polar molecules that are pushed and aggregated into this fixed space by the electric field. The enriched structure is essentially a collection of polar molecules that reaches a stable concentrated state after adsorption time timing based on the trapped body. It contains a group of polar molecules that remain non-diffused, non-dispersed, and maintain a high-density arrangement within the preset adsorption time. In S2-3, it should be noted that the local space near the second electrode plate refers to a small, fixed area within the electric field trapping cavity, close to the second electrode plate. This area is where all the polar molecules pushed by the electric field finally stop, so it is used as the place to determine whether the aggregation is complete. The number of polar molecules is the number of polar molecules that have entered this region. The statistical method includes: each time a polar molecule migrates into this region, the molecule is counted and accumulated, so that we can get the total number of polar molecules in this region at present. The number of polar molecules per unit volume is calculated by dividing the counted number of polar molecules by the volume of the region, thus determining the polar molecule concentration in that region at the current time point. The upper limit of compressibility density is a maximum concentration that can be accommodated in this region. This upper limit is calculated in advance based on factors such as the volume of this region, the electric field strength, and the nearest accessible distance between molecules. It indicates how many polar molecules this region can hold at most. The determination of completed aggregation involves comparing the number of polar molecules per unit volume with the upper limit of compressibility. If the number per unit volume reaches the upper limit of the compressibility density, it means that this area has been filled and can be marked as a captured body; if it has not yet reached the upper limit, continue to accumulate newly migrated polar molecules and continue to count. Adsorption time is the time elapsed after the trap is formed. The measurement method is as follows: once it is marked as a trap, the timer starts and is continuously increased over time until the set upper limit of adsorption time is reached. At this point, it is confirmed that the trap has formed a stable concentrated state and is used as the enrichment structure for subsequent steps. The reason why this method can be used in S2-3 is that polar molecules will naturally concentrate near the second electrode plate after being attracted by the electric field. This area is the final accumulation location of polar molecules. By counting the number of them in this area and determining whether it is filled, and then combining this with the time taken for adsorption, it can be determined whether this area has truly completed the entire process of "from migration to concentration to stability". Therefore, this method of judgment is clear, executable and quantifiable.

[0025] S3 includes: S3-1. After the enriched structure is formed, the output condition is determined: the number of polar molecules in the local space of the trapped body is calculated and the unit volume density is obtained. The unit volume density is compared with the preset upper limit of the compressibility density. At the same time, the adsorption time is timed and the timed result is compared with the upper limit of the adsorption time. When both comparison results meet the upper limit conditions, it is determined that the enriched structure has reached the preset output condition. Otherwise, the density statistics and adsorption time timing are continued. S3-2. After determining that the enrichment structure has reached the preset output condition, disconnect the potential connection between the first electrode plate and the second electrode plate. By making the potential of the two electrode plates return to the zero potential position of the power supply at the same time, the directional electric field that originally limited the polar molecules completely disappears, and the polar molecules in the captured state in the enrichment structure are no longer bound by the electric field. S3-3. After removing the directional electric field, a flow drive is applied inside the electric field trapping cavity. By establishing a constant pressure difference between the gas inlet and the gas outlet, the polar molecules in the enriched structure are continuously displaced along the gas outlet direction. During the continuous displacement, the initial concentrated distribution of the enriched structure is kept intact, and the polar molecules move as a whole in an aggregated state. In S3-1, it should be noted that the determination of whether the captured body meets the output conditions requires two independent and parallel calculations: the number of polar molecules in the local space of the captured body and the corresponding adsorption time of the captured body. The captured body is a concentrated region formed in the local space near the second electrode plate after the polar molecules reach the upper limit of the compressibility density. Therefore, the calculation of the number of polar molecules uses each polar molecule entering this local space as the counting unit. The total number is obtained by recording the number of polar molecules entering the captured body space at each time step and summing them up. The unit volume density is obtained by dividing the cumulative number by the fixed volume of the captured body space and is used to reflect the concentration state of the captured body. The preset upper limit of compressibility density is used to determine whether the captured body meets the output conditions. The concentration threshold is determined based on the volume of the trapping body, the electric field strength of the electric trapping cavity, and the maximum achievable packing density of polar molecules in that space. The adsorption time is calculated by accumulating the time of each consecutive time step, starting from the time when the trapping body is marked. The upper limit of the adsorption time is a preset time threshold, which is determined based on the shortest time required for polar molecules to reach a stable and concentrated state in the trapping body. During the judgment process, the unit volume density is compared with the preset upper limit of compressibility density, and the adsorption time is compared with the upper limit of adsorption time. When both comparison results meet the upper limit conditions, the trapping body is marked as an enriched structure and the preset output conditions are met. Otherwise, the process of calculating the number of polar molecules and the adsorption time continues. In S3-2, it should be noted that: to disconnect the potential connection between the first and second electrode plates, it is necessary to disconnect the conductive path between the first electrode plate and the positive terminal of the power supply, and simultaneously disconnect the conductive path between the second electrode plate and the negative terminal of the power supply, so that the two electrode plates lose the potential difference provided by the external power supply; after disconnecting the conductive path, the two electrode plates are connected to the zero potential port of the power supply respectively, so that the potentials of the first and second electrode plates return to the zero potential position at the same time; since the formation of the directional electric field depends entirely on the potential difference between the first and second electrode plates, when the two electrode plates are at the same potential, the potential difference is calculated as zero, and when the potential difference is zero, the electric field strength inside the electric field trapping cavity is also calculated as zero. Therefore, the directional electric field originally formed inside the electric field trapping cavity completely disappears; after the directional electric field disappears, the polar molecules in the trapped state in the enriched structure lose the driving force to continuously migrate to the second electrode plate, and are no longer bound by the electric field in the trapping region, thus transforming into a free distribution state, providing a releaseable initial state for the subsequent flow driving steps; In S3-3, it should be noted that for the process of applying flow drive to the inside of the electric field trapping cavity, the pressure difference between the gas inlet and the gas outlet is required as the driving force source. Flow drive is defined as the process of moving the mixed gas and enrichment structure as a whole through pressure difference in a closed flow path. This driving method achieves stable propulsion of the gas in the flow path by applying a fixed pressure at the gas inlet end that is higher than that at the gas outlet end, so that the enrichment structure can generate continuous displacement along a predetermined direction. The flow drive is applied by using an external gas supply device connected to the flow path inlet. The pressure value output by the gas supply device is used as the inlet pressure, and the gas outlet is kept at a fixed low pressure end, so that a pressure difference is formed between the inlet pressure and the outlet pressure. The constant pressure difference refers to the fixed value obtained by subtracting the outlet pressure from the inlet pressure. In order to establish this constant pressure difference, the inlet pressure needs to be adjusted to a fixed value higher than the outlet pressure, and the output pressure of the gas supply device needs to be kept constant. At the same time, the outlet end is kept at a fixed low pressure or close to atmospheric pressure, so that the pressure difference between the inlet and the outlet remains constant throughout the driving process. Once a constant pressure difference is established, the polar molecules in the enriched structure undergo continuous displacement along the gas outlet direction under the pressure difference. Since the enriched structure is essentially a collection of polar molecules stably aggregated within the trapping space, the relative positions of the internal polar molecules are determined by the concentrated state formed by the adsorption time. Therefore, under the flow-driven action, the internal polar molecules move as a whole under the pressure difference without generating a significant internal velocity difference, thus avoiding the dispersion of the concentrated distribution. During the continuous displacement process, the internal concentration distribution of the enriched structure remains stable, allowing the enriched structure to move as an aggregated unit, ensuring that the high concentration characteristic is maintained during output.

[0026] S3 also includes: S3-4. When the enriched structure is shifted to the gas outlet, the flow rate of the polar molecules is synchronized and integrated. By combining the instantaneous flow rate at the outlet with the instantaneous density of molecules on the outlet cross section, a continuously changing concentration distribution is constructed and a concentration output flow is formed. If the instantaneous density at the outlet does not meet the preset continuous output requirement, the flow drive is continuously executed until a continuous concentration output flow is formed. In S3-4, it should be noted that the output process after the enriched structure is moved to the gas outlet requires continuous displacement driven by flow as a prerequisite, so that the enriched structure can be advanced to the outlet position along the gas outlet direction. When the leading edge of the enriched structure coincides with the gas outlet section, polar molecules released by the enriched structure will begin to appear at the outlet position. Therefore, it is necessary to perform flow rate integration and synchronization on these polar molecules in order to construct a stable concentration output flow for subsequent optical detection. Flow rate integration and synchronization is defined as simultaneously acquiring instantaneous gas flow rate data and instantaneous polar molecule density data at the outlet section, so that the two sets of data correspond under the same time reference and can be used for subsequent calculation of instantaneous concentration. The instantaneous flow rate at the outlet is obtained by a miniature flow rate sensor installed in the gas outlet channel. This flow rate sensor records the speed of gas passing through the outlet section per unit time at fixed time steps. The instantaneous molecule density at the outlet section is obtained by recording the number of polar molecules appearing in the effective detection area of ​​the outlet section within the same time step and dividing this number by the effective detection volume of the outlet section, thus obtaining the instantaneous density at that time step. After obtaining the instantaneous flow rate and instantaneous density at the outlet, multiplying the instantaneous flow rate by the instantaneous density yields the instantaneous concentration at that time step. Combining the instantaneous concentrations of consecutive time steps in a time series allows the construction of a concentration distribution that changes continuously over time. This continuous concentration distribution records the overall change in polar molecules within the enriched structure as they are pushed out of the outlet over time. When the instantaneous concentrations of consecutive time steps appear consecutively at the outlet, a concentration output stream is formed. The concentration output stream, composed of the instantaneous concentrations of the continuous time series, incorporates a combination of flow rate, molecular density, and time variation, and can serve as the concentration input source for subsequent optical detection. The instantaneous outlet density refers to the value obtained by dividing the number of polar molecules passing through the outlet cross section by the detection volume of the outlet cross section within a certain time step. When the instantaneous outlet density is lower than the preset continuous output requirement, it will cause the instantaneous concentration to be discontinuous. The preset continuous output requirement includes conditions such as the instantaneous outlet density needing to remain non-zero within multiple adjacent time steps, remaining within the detectable range, and the variation range being within the allowable range. These conditions are preset based on the minimum detection concentration and minimum continuity requirements required for subsequent optical detection. When the instantaneous density at the outlet does not meet the above-mentioned preset requirements, the polar molecules inside the enrichment structure are further propelled towards the outlet by continuing to maintain the flow drive on the inlet side, continuously generating new instantaneous densities. Under the continuous action of the flow drive, polar molecules will be continuously detected at the outlet section until the preset continuous output requirements are met, at which point a continuous concentration output stream can be formed. The concentration output flow is essentially a continuous gas flow formed by the overall movement of the enriched structure after the directional electric field is removed and a constant pressure difference is applied. It maintains the original high-density polar molecule concentration state and contains polar molecules in the enriched structure, which are output from the gas outlet at a stable flow rate.

[0027] S4 includes: S4-1. After the concentration output flow reaches the optical detection position, the detection optical path is constructed into a continuous transmission chain by sequentially forming the incident optical path, the gas absorption path, and the exit optical path. The optical path filling calculation is performed on the gas absorption path: the real-time flow rate is obtained by monitoring the pressure difference between the inlet and outlet of the gas absorption path, and then the real-time filling ratio of the absorption path is calculated by converting the real-time flow rate, and the real-time filling ratio is compared with the full-load filling ratio. If the comparison results are consistent, proceed to the next execution step; otherwise, adjust the flow rate drive until the two are consistent. S4-2. At the incident end of the detection optical path, the tunable laser is used as the input source and wavelength scanning configuration is performed on its internal tuning chain: First, the minimum and maximum scanning wavelengths are calculated based on the target absorption range. Then, the feedback error of the frequency controller is used as the adjustment reference, and the continuously changing output wavelength is obtained by adjusting the effective length of the resonant cavity. The output power is calculated at each wavelength point and compared with the lower power limit. If the output power is lower than the lower power limit, the resonant cavity compensation amount is recalculated and compensation adjustment is performed. Otherwise, the wavelength scanning continues. S4-3. After the tunable laser completes continuous scanning configuration, the laser beam passes through the gas absorption path completely filled by the concentration output stream, and the absorption is calculated for each scanning wavelength: the incident light intensity and the output light intensity are obtained sequentially, and the difference between the two is taken as the absorption of that wavelength; at the same time, the absorption is judged for stability. When the light intensity difference falls into the stable range, the absorption is recorded. Otherwise, the wavelength is scanned repeatedly and the average value of the repeated scans is taken as the final absorption. In S4-1, it should be noted that for the processing after the concentration output stream reaches the optical detection position, the detection optical path needs to be constructed as a continuous transmission chain at that position first, and then optical path filling calculation is performed on the gas absorption path after the construction is completed. The optical detection position is the position where the concentration output stream connects to the gas inlet of the detection optical path after flowing through the electric field trapping cavity. At this position, the detection optical path is formed by arranging the incident optical path, the gas absorption path, and the exit optical path in sequence. The incident optical path is the light propagation channel from the tunable laser output end to the gas absorption path inlet, and the gas absorption path is the path that is filled with the concentration output stream and has... A gas absorption cell with a fixed optical path length has an output optical path that is the light propagation channel from the gas absorption path outlet to the light intensity detector. The continuous transmission chain of the detection optical path is implemented by aligning and fixing the end of the incident optical path with the inlet of the gas absorption path in terms of physical structure, and then aligning and fixing the outlet of the gas absorption path with the start of the output optical path. This allows the laser beam to propagate continuously in the order of the incident optical path, the gas absorption path, and the output optical path. The gas absorption path refers to the effective optical path region inside the gas absorption cell along the light propagation direction. This region is also the space through which the concentration output stream actually passes and undergoes absorption. During optical path filling calculation, pressure sensors are installed at the inlet and outlet of the gas absorption path to collect inlet and outlet pressures in real time, and the difference between the two is calculated as the pressure difference between the inlet and outlet of the gas absorption path. Then, this pressure difference is combined with the preset cross-sectional area of ​​the gas absorption path and gas physical parameters to solve the real-time flow rate of the current time step using fluid dynamics formulas. The real-time filling ratio is calculated by comparing the real-time flow rate with the full-load flow rate of the gas absorption path under full load conditions. The full-load filling ratio is set to 1, which corresponds to the state in which the gas absorption path is just completely updated by the concentration output flow within a unit time without any cavities. At each time step, the real-time filling ratio is compared with the full-load filling ratio. When the real-time filling ratio is equal to 1, it is determined that the gas absorption path is completely filled by the concentration output flow and the next execution step is entered. Otherwise, the output pressure or flow rate setting value of the flow drive device connected to the front end of the gas absorption path is adjusted to increase or decrease the real-time flow rate, and the pressure difference measurement, real-time flow calculation and real-time filling ratio calculation are repeated until the real-time filling ratio is consistent with the full-load filling ratio. In S4-2, it should be noted that for the wavelength scanning configuration of the tunable laser, the tunable laser needs to be used as the sole input source at the incident end of the detection optical path, and a series of wavelength and power calculation and adjustment processes are performed around its internal tuning chain. The target absorption range is predetermined based on the characteristic absorption band of the precursor gas of deterioration. The lower limit wavelength of the target absorption range is used as the minimum scanning wavelength, and the upper limit wavelength of the target absorption range is used as the maximum scanning wavelength. In the tuning chain, the minimum scanning wavelength and the maximum scanning wavelength are respectively recorded as the wavelength scanning start point and wavelength scanning end point. The frequency controller inside the tunable laser is used as the control core. At each time step, the difference between the target frequency setting value of the frequency controller and the actual laser output frequency is read. This difference is defined as the feedback error of the frequency controller, and the feedback error is used as the adjustment benchmark. The effective length change of the resonant cavity that should be adjusted is solved through the functional relationship between the frequency and the resonant cavity length. The effective length of the resonant cavity is increased or decreased according to this change, thereby forming a continuously changing output wavelength from the minimum scanning wavelength to the maximum scanning wavelength in the time series. At each solved output wavelength point, the output optical power of the tunable laser at that wavelength is measured by the power detection module. The measured output power is compared with the preset power lower limit. When the output power is greater than or equal to the power lower limit, the wavelength point is determined to meet the scanning requirements and the process moves to the next wavelength point. When the output power is less than the power lower limit, the resonant cavity compensation amount is recalculated with the current feedback error and power deviation as input. The compensation amount is added to the adjustment command of the effective length of the resonant cavity, and the effective length of the resonant cavity is adjusted again. The output power measurement and comparison with the power lower limit are repeated at that wavelength point until the output power at that wavelength point meets the power lower limit requirement. Then, the wavelength scanning continues to the next wavelength point. In S4-3, it should be noted that for each scanning wavelength after the tunable laser completes continuous scanning configuration, the absorption calculation and stability judgment need to be performed in a fixed order. To this end, before the laser beam enters the gas absorption path, the incident light intensity detector is set at the end of the incident light path and the output light intensity detector is set at the beginning of the output light path, so that the laser beam generates measurable light intensity values ​​at the two detection positions after passing through the gas absorption path completely filled by the concentration output stream. Subsequently, at each scanning wavelength point, the laser beam is kept stably output at that wavelength, and the incident light intensity corresponding to that wavelength is first obtained through the incident light intensity detector, and then the output light intensity corresponding to that wavelength is obtained through the output light intensity detector. The absorption at that wavelength is calculated based on the difference between the two, and the absorption is defined as the absorption difference at that wavelength. After obtaining the absorption difference, a stability judgment is performed on the absorption difference: by comparing the absorption difference between the lower limit and the upper limit of the preset stable interval, if the absorption difference falls into the stable interval, the absorption difference is recorded as the final absorption of the wavelength; if the absorption difference does not fall into the stable interval, the wavelength is added back to the scanning sequence, and the calculation of the incident light intensity, the output light intensity, and the absorption difference is repeated for the wavelength. The average of the multiple absorption differences obtained from the repeated scanning is calculated, and the average absorption difference is recorded as the final absorption of the wavelength.

[0028] S4 also includes: S4-4. After obtaining the absorption amount covering the entire scanning range, the absorption amounts are constructed into a data chain arranged with a fixed step size according to the scanning order, and the step size consistency is checked on the data chain: the actual step size between any adjacent wavelength points is calculated and compared with the upper limit of step size deviation. When all step sizes meet the deviation requirements, the data chain is defined as the absorption data sequence; if there are wavelength segments that exceed the upper limit of deviation, interpolation correction is performed to fill in the missing wavelength points, and then the corrected data chain is defined as the absorption data sequence covering the target absorption range. In S4-4, it should be noted that for the absorption covering the entire scanning range, an absorption data sequence that meets the fixed step size requirement needs to be constructed through calculation and verification. First, based on the actual scanning sequence of the tunable laser, each scanning wavelength and its corresponding absorption are arranged in chronological order to form an initial data chain consisting of wavelength-absorption pairs. When constructing the data chain, each wavelength point is assigned a sequential index for subsequent step size calculation. Subsequently, a step size consistency check is performed on the initial data chain: for each pair of adjacent wavelength points, the actual step size of the pair is obtained by subtracting the previous wavelength from the subsequent wavelength, and this actual step size is compared with the preset target step size. The step size deviation is calculated by the difference between the actual step size and the target step size, and then compared with the preset upper limit of the step size deviation. When the step size deviation of each pair of adjacent wavelength points does not exceed the upper limit of the step size deviation, the data chain as a whole is determined to meet the fixed step size requirement, and the data chain is directly defined as an absorption data sequence. If, during the step size consistency check, the step size deviation of one or more pairs of adjacent wavelength points exceeds the upper limit of the step size, the data chain is considered to meet the fixed step size requirement. If the deviation is deemed too high, these wavelength segments are identified as anomalous segments with missing wavelength points. Interpolation correction is then performed on each anomalous segment: based on the target step size between the start and end wavelengths of the anomalous segment, an intermediate wavelength point that should exist within the segment is generated, and this intermediate wavelength point is inserted into the data chain. The absorption of the intermediate wavelength point is calculated using an interpolation algorithm based on the known absorption at both ends of the anomalous segment, and the interpolation result is added to the corresponding position in the data chain. After interpolation correction is completed for all anomalous segments, the coverage of the corrected data chain is reconfirmed to be consistent with the target absorption range, and the corrected data chain is defined as the absorption data sequence covering the target absorption range.

[0029] S5 includes: S5-1. For each preset precursor gas of deterioration, read the three absorbance values ​​corresponding to its main absorption peak wavelength, front shoulder peak wavelength, and rear shoulder peak wavelength from the absorption data sequence. Then, perform a weighted summation of the three absorbance values ​​according to the pre-calibrated center peak weighting coefficient, front shoulder peak weighting coefficient, and rear shoulder peak weighting coefficient, and add a preset offset to calculate the instantaneous concentration of the gas. If any one of the three absorbance values ​​is missing, the instantaneous concentration of the gas is recorded as zero. S5-2. Perform an existence quantity judgment on the instantaneous concentration of each precursor gas of degradation. Compare the instantaneous concentration with the lower limit and upper limit of the existence quantity of the precursor gas of degradation. When the instantaneous concentration is greater than or equal to the lower limit of the existence quantity and less than or equal to the upper limit of the existence quantity, the instantaneous concentration is taken as the effective existence quantity of the precursor gas of degradation. Otherwise, the effective existence quantity of the precursor gas of degradation is recorded as zero, and the effective existence quantities of all precursor gases of degradation are combined into an existence quantity vector. In S5-1, it should be noted that: for the preset precursor gases of deterioration, a set of target gases needs to be determined during the calibration stage. Each preset precursor gas of deterioration corresponds to a specific gaseous component related to quality deterioration in the kiwifruit storage space, such as ethanol, acetaldehyde, or a specific organic acid. Then, the main absorption peak wavelength, the front shoulder peak wavelength, and the rear shoulder peak wavelength are determined for each preset precursor gas of deterioration. The main absorption peak wavelength is obtained by scanning the absorption spectrum of a standard sample gas using the gas during the calibration stage, and selecting the peak position of the gas absorption intensity in the absorption spectrum as the main absorption peak wavelength. The front shoulder peak wavelength is obtained by shifting the main absorption peak wavelength to a lower wavelength direction by a preset wavelength step, and selecting the wavelength point on the absorption curve at the step position where the absorption intensity is at the edge of the main peak. The rear shoulder peak wavelength is obtained by shifting the main absorption peak wavelength to a higher wavelength direction by the same preset wavelength step, and selecting the wavelength point on the absorption curve at the step position where the absorption intensity is at the other side edge of the main peak. After obtaining the three wavelength positions, a series of standard sample gases with known concentrations were prepared for each preset precursor gas of deterioration during the calibration stage. The absorption of each sample gas at the main absorption peak wavelength, the front shoulder peak wavelength, and the rear shoulder peak wavelength were measured in sequence, and these absorption values ​​and the corresponding true concentration values ​​were recorded. Based on this, with the true concentration as the target quantity and the absorption at the three wavelengths as the input quantity, a linear relationship was established consisting of the center peak weighting coefficient, the front shoulder peak weighting coefficient, the rear shoulder peak weighting coefficient, and the offset. By performing least squares error calculation on multiple sets of standard sample gas data, a set of center peak weighting coefficients, the front shoulder peak weighting coefficients, the rear shoulder peak weighting coefficient, and the offset that minimizes the total error between the calculated concentration and the true concentration was obtained. This set of coefficients and the offset were then solidified as the calibration parameters for the gas. During the monitoring phase, for each preset precursor gas of deterioration, the absorbance corresponding to the wavelength of the main absorption peak, the absorbance corresponding to the wavelength of the preceding shoulder peak, and the absorbance corresponding to the wavelength of the following shoulder peak are read from the absorption data sequence. The absorbance of the main absorption peak is multiplied by the weighting coefficient of the central peak, the absorbance of the preceding shoulder peak is multiplied by the weighting coefficient of the preceding shoulder peak, and the absorbance of the following shoulder peak is multiplied by the weighting coefficient of the following shoulder peak. These three products are then summed, and the result is added to the offset obtained from calibration. The result is defined as the instantaneous concentration of the precursor gas of deterioration at the current moment. When any of the three absorbance values ​​is missing in the absorption data sequence, it indicates that the spectral information at the three key positions at the current moment is incomplete, and the concentration of the gas cannot be stably solved according to the calibration relationship. In this case, the instantaneous concentration of the gas is directly recorded as zero to avoid outputting distorted concentration results based on incomplete data. In S5-2, it should be noted that for each preset pre-deterioration gas whose instantaneous concentration has been calculated in S5-1, an existence quantity judgment needs to be performed around its actual determinable range to ensure that only the instantaneous concentration falling within the confidence interval is considered a valid existence quantity. To this end, during the calibration phase, a lower limit and an upper limit of existence quantity are determined for each preset pre-deterioration gas. The lower limit of existence quantity is determined by gradually decreasing the gas concentration using a standard sample gas of the gas and recording the change in absorption. The lowest concentration point where the change in absorption can be stably distinguished from background noise is taken as the lower limit of existence quantity. The upper limit of existence quantity is determined by gradually increasing the concentration of the standard sample gas of the gas and recording the change in absorption. The maximum distinguishable concentration point before absorption saturation occurs, where the absorption no longer increases linearly with the concentration, is taken as the upper limit of existence quantity. During the monitoring phase, for each preset precursor gas of deterioration, the instantaneous concentration obtained from S5-1 is compared numerically with the calibrated lower and upper limits of the gas's presence. When the instantaneous concentration is greater than or equal to the lower limit and less than or equal to the upper limit, it indicates that the instantaneous concentration is within the effective judgment range of the gas, and the instantaneous concentration is directly recorded as the effective presence of the gas. When the instantaneous concentration is less than the lower limit or greater than the upper limit, it indicates that the current instantaneous concentration is not within the effective judgment range and cannot stably reflect the true presence of the gas in the kiwifruit storage space based on the absorption spectrum. In this case, the effective presence of the gas is recorded as zero to avoid misjudgment due to weak signals or absorption saturation. Subsequently, the effective presence of each preset precursor gas of deterioration is combined in a fixed order to form a complete presence vector, which serves as the input data structure for subsequent deterioration risk calculation.

[0030] S5 also includes: S5-3. Perform degradation risk calculation on the existence vector. Multiply the effective existence quantity of each degradation precursor gas in the existence vector with the corresponding preset risk coefficient and sum them to obtain the degradation risk value. Compare the degradation risk value with the preset first risk threshold and second risk threshold. When the degradation risk value is less than the first risk threshold, the kiwifruit storage space is calculated as the first degradation risk state. When the degradation risk value is greater than or equal to the first risk threshold and less than the second risk threshold, the kiwifruit storage space is calculated as the second degradation risk state. When the degradation risk value is greater than or equal to the second risk threshold, the kiwifruit storage space is calculated as the third degradation risk state. In S5-3, it should be noted that for the existence vector already generated in S5-2, the deterioration risk value needs to be solved according to a clear calculation order, and the calculated risk value should be converted into three different risk states of the kiwifruit storage space based on two specific risk thresholds. To this end, it is necessary to first clarify the meaning of each effective existence quantity in the existence vector. The effective existence quantity is the actual concentration of a certain deterioration precursor gas at the current monitoring time. This concentration has been calculated in S5-1 by combining the three-wavelength absorption and calibration coefficient, and determined in S5-2 by the lower limit and upper limit of the existence quantity. Therefore, the effective existence quantity represents the true degree of existence of the gas in the current storage space and can be directly involved in the risk calculation. Before calculating the risk value of deterioration, a risk coefficient needs to be configured for each precursor gas of deterioration. The risk coefficient is calculated from the previous calibration experimental scheme. By changing the actual concentration of the gas in a controlled environment and recording the changes in three indicators: the rate of decrease in kiwifruit firmness, the rate of decrease in soluble solids, and the rate of expansion of spoilage area, a linear function model is established based on the changes in these three indicators relative to the gas concentration. The risk coefficient is then obtained from the slope of the linear function model. The larger the risk coefficient, the stronger the impact of the gas on the decline in kiwifruit quality. Therefore, the risk coefficient is used to bring the effective presence of different gases back to a unified scale of influence. In risk calculation, the effective quantity of each precursor gas of deterioration in the quantity vector is multiplied by its corresponding risk coefficient, and all products are summed. The summed value is used as the deterioration risk value. In order to determine the storage state corresponding to the risk value, two clear risk thresholds need to be set in the calibration stage. In addition, the first risk threshold can be the lowest risk value at which signs of quality decline are observed in kiwifruit during continuous monitoring of kiwifruit quality indicators in the experiment. These signs include a decrease in firmness and a slight change in odor without visible spoilage. The second risk threshold can be the lowest risk value at which the rate of quality decline in kiwifruit increases significantly in the experiment. These changes include the appearance of rotten spots, an accelerated decrease in soluble solids, and localized softening of the flesh. The first and second risk thresholds correspond to two different stages of quality change. They may not be upper or lower limits, but rather two dividing points used to divide the risk value into three independent regions. When assessing risk, if the risk value of deterioration is less than the first risk threshold, the current storage space is classified as the first risk state, indicating that the quality of the kiwifruit is temporarily stable and existing storage measures can be maintained. If the risk value of deterioration is greater than or equal to the first risk threshold but less than the second risk threshold, the storage space is classified as the second risk state, indicating that deterioration factors have appeared but have not reached the stage of rapid deterioration, and storage conditions need to be adjusted, such as lowering the temperature or increasing gas exchange. If the risk value of deterioration is greater than or equal to the second risk threshold, the storage space is classified as the third risk state, indicating that the kiwifruit has entered the stage of rapid deterioration, and strong intervention measures need to be taken immediately, such as rapid cooling, emergency batch processing, or termination of storage. Furthermore, the first and second risk thresholds can also be set as upper and lower limits, with the first risk threshold as the lower limit of the risk value and the second risk threshold as the upper limit of the risk value, so that the deterioration risk value corresponds to an intermediate risk state within the range of the upper and lower limits, a low risk state below the lower limit, and a high risk state above the upper limit.

[0031] The overall working principle of this invention is as follows: This invention uses a flow path structure, an electric field trapping cavity, a detection optical path, and a tunable laser detection link to form an intelligent sensing system for monitoring the deterioration of kiwifruit during storage. First, the mixed gas released collectively by the kiwifruit in the storage space is collected and transported in the flow path structure with a stable flow rate, stable pressure, and unidirectional flow direction, so that the mixed gas maintains the same component ratio as the storage space before entering the electric field trapping cavity. After the mixed gas enters the electric field trapping cavity of the intelligent sensing system, a preset potential is applied through a pair of electrode plates to form a directional electric field between the electrodes, which attracts the deterioration precursor gas molecules with dipole moments and continuously gathers near the second electrode plate; when the number of molecules in this local space reaches the upper limit of the compression density and maintains sufficient adsorption time, an enriched structure is formed. Then the electrode potential is cut off to make the directional electric field disappear. A constant pressure difference is then established between the inlet and outlet of the electric field trapping cavity to push the enriched structure out as a whole, so that it passes through the outlet in an aggregated state without being broken up, and forms a continuous and stable high-concentration output flow at the outlet. The concentration output stream is then fed into the detection optical path of the intelligent sensing system to completely fill the gas absorption path; a tunable laser is used to perform continuous wavelength scanning at the incident end, and the light intensity difference before and after gas absorption is measured at each scanning wavelength to form an absorption data sequence arranged in a fixed wavelength step. Based on the absorption data sequence, the absorption amount of the main absorption peak and the two shoulder peaks of each preset precursor gas of deterioration is read under edge computing. The instantaneous concentration is calculated according to the weighting coefficient obtained by calibration, and the effective existence amount is obtained by screening the upper and lower limits of existence amount. Then, all the effective existence amounts are combined into an existence amount vector, and the deterioration risk value is generated by summing with the preset risk coefficient. Then, it is compared with the first risk threshold and the second risk threshold, and finally the kiwifruit storage space is calculated as low risk, medium risk or high risk. Through the chain process of electric field enrichment, optical detection, edge computing, and risk calculation, the intelligent sensing system can continuously and quantitatively monitor the risk of deterioration of kiwifruit during storage.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis, characterized in that, include: S1. Introduce a flow path for mixed gas in the kiwi fruit storage space and guide the mixed gas into the inlet of the electric field trapping cavity, so that the mixed gas entering the electric field trapping cavity maintains the original component ratio of the storage space. S2. Apply a preset potential inside the electric field trapping cavity to form a trapping region for polar molecules inside the electric field trapping cavity, and adsorb the deterioration precursor gas in the mixed gas in the trapping region to form an enrichment structure corresponding to the adsorption time. S3. After the enrichment structure reaches the preset output conditions, the potential control of the trapping region is released, and the enriched gas in the enrichment structure is output through the gas outlet of the electric field trapping cavity, so that the output gas forms a concentration output stream. S4. Introduce the concentration output stream into the detection optical path, and use a tunable laser to form a continuous wavelength scan in the detection optical path. Record the absorption changes of the corresponding band during the scan to generate an absorption data sequence covering the target absorption range. S5. Identify the presence of precursor gases based on the absorption data sequence, and determine the deterioration risk status of the kiwifruit storage space based on the identification results.

2. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 1, characterized in that: S1 includes: S1-1. In the kiwifruit storage space, the mixed gas released by the kiwifruit collectively is collected and defined as the input gas entering the subsequent processing structure; the mixed gas includes carbon dioxide and ethanol. S1-2. Construct a flow path structure consisting of a flow path inlet, a flow path channel, and an electric field trapping cavity connected to the flow path channel. The electric field trapping cavity consists of a cavity shell, an internal electrode assembly, a gas inlet, and a gas outlet, and is used to perform electric field trapping operations on the mixed gas. S1-3. After the mixed gas enters the flow path structure, the flow state of the mixed gas in the flow path channel is controlled so that the mixed gas maintains the same component ratio as the kiwi fruit storage space without component separation, and the mixed gas with the same component ratio is guided to the gas inlet of the electric field trapping cavity. S1-4. After the mixed gas enters the gas inlet of the electric field trapping cavity, the mixed gas is driven by flow to form the input structure of the gas to be trapped inside the electric field trapping cavity.

3. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 2, characterized in that: S2 includes: S2-1. Two conductive electrode plates are arranged opposite each other in the internal electrode assembly of the electric field trapping cavity. The conductive electrode plate near the mixed gas inlet is defined as the first electrode plate, and the conductive electrode plate arranged opposite to the first electrode plate is defined as the second electrode plate. The first electrode plate is connected to the positive terminal of the power supply, and the second electrode plate is connected to the negative terminal of the power supply, so as to construct a directional electric field in the trapping region between the first electrode plate and the second electrode plate. S2-2. Perform polarity determination on each molecule in the mixed gas entering the electric field trapping cavity, define molecules with dipole moments as polar molecules, and calculate the migration speed and displacement of polar molecules based on the electric field strength and the dipole moments of polar molecules under the action of the directional electric field. Converge polar molecules whose displacement reaches the preset migration threshold to the local space near the second electrode plate. S2-3. Count the number of polar molecules in the local space near the second electrode plate, and perform aggregation completion judgment based on the relationship between the number of polar molecules per unit volume and the upper limit of compression density. Mark the local space where the number of polar molecules per unit volume reaches the preset upper limit of compression density as a trap. Perform adsorption time timing on the trap and mark the trap where the adsorption time reaches the preset upper limit of adsorption time as the enriched structure corresponding to the adsorption time.

4. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 3, characterized in that: S3 includes: S3-1. After the enriched structure is formed, the output condition is determined: the number of polar molecules in the local space of the trapped body is calculated and the unit volume density is obtained. The unit volume density is compared with the preset upper limit of the compressibility density. At the same time, the adsorption time is timed and the timed result is compared with the upper limit of the adsorption time. When both comparison results meet the upper limit conditions, it is determined that the enriched structure has reached the preset output condition. Otherwise, the density statistics and adsorption time timing are continued. S3-2. After determining that the enrichment structure has reached the preset output condition, disconnect the potential connection between the first electrode plate and the second electrode plate. By making the potential of the two electrode plates return to the zero potential position of the power supply at the same time, the directional electric field that originally limited the polar molecules disappears, and the polar molecules in the captured state in the enrichment structure are no longer bound by the electric field. S3-3. After removing the directional electric field, a flow drive is applied inside the electric field trapping cavity. By establishing a constant pressure difference between the gas inlet and the gas outlet, the polar molecules in the enriched structure are continuously displaced along the gas outlet direction.

5. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 4, characterized in that: S3 also includes: S3-4. When the enrichment structure is shifted to the gas outlet, the flow rate of the polar molecules moving out is integrated and synchronized. By combining the instantaneous flow rate at the outlet with the instantaneous density of molecules on the outlet cross section, a continuously changing concentration distribution is constructed and a concentration output flow is formed. If the instantaneous density at the outlet does not meet the preset continuous output requirement, the flow drive is continuously executed until a continuous concentration output flow is formed.

6. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 5, characterized in that: S4 includes: S4-1. After the concentration output flow reaches the optical detection position, the detection optical path is constructed into a continuous transmission chain by sequentially forming the incident optical path, the gas absorption path, and the exit optical path. The optical path filling calculation is performed on the gas absorption path: the real-time flow rate is obtained by monitoring the pressure difference between the inlet and outlet of the gas absorption path, and then the real-time filling ratio of the absorption path is calculated by converting the real-time flow rate, and the real-time filling ratio is compared with the full-load filling ratio. If the comparison results are consistent, proceed to the next execution step; otherwise, adjust the flow rate drive until the two are consistent. S4-2. At the incident end of the detection optical path, the tunable laser is used as the input source and wavelength scanning configuration is performed on its internal tuning chain: First, the minimum and maximum scanning wavelengths are calculated based on the target absorption range. Then, the feedback error of the frequency controller is used as the adjustment reference, and the continuously changing output wavelength is obtained by adjusting the effective length of the resonant cavity. The output power is calculated at each wavelength point and compared with the lower power limit. If the output power is lower than the lower power limit, the resonant cavity compensation amount is recalculated and compensation adjustment is performed. Otherwise, the wavelength scanning continues. S4-3. After the tunable laser completes continuous scanning configuration, the laser beam passes through the gas absorption path completely filled by the concentration output stream, and the absorption is calculated for each scanning wavelength: the incident light intensity and the output light intensity are obtained sequentially, and the difference between the two is taken as the absorption of that wavelength; at the same time, the stability of the absorption is judged. When the light intensity difference falls into the stable range, the absorption is recorded. Otherwise, the wavelength is scanned repeatedly and the average value of the repeated scans is taken as the final absorption.

7. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 6, characterized in that: S4 also includes: S4-4. After obtaining the absorption amount covering the entire scanning range, construct each absorption amount into a data chain arranged with a fixed step size according to the scanning order, and perform a step size consistency check on the data chain: calculate the actual step size between any adjacent wavelength points and compare it with the upper limit of step size deviation. When all step sizes meet the deviation requirements, define the data chain as an absorption data sequence; if there are wavelength segments that exceed the upper limit of deviation, perform interpolation correction to fill in the missing wavelength points, and then define the corrected data chain as an absorption data sequence covering the target absorption range.

8. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 7, characterized in that: S5 includes: S5-1. For each preset precursor gas of deterioration, read the three absorbance values ​​corresponding to its main absorption peak wavelength, front shoulder peak wavelength, and rear shoulder peak wavelength from the absorption data sequence. Then, perform a weighted summation of the three absorbance values ​​according to the pre-calibrated center peak weighting coefficient, front shoulder peak weighting coefficient, and rear shoulder peak weighting coefficient, and add a preset offset to calculate the instantaneous concentration of the gas. If any one of the three absorbance values ​​is missing, the instantaneous concentration of the gas is recorded as zero. S5-2. Perform an existence quantity judgment on the instantaneous concentration of each precursor gas of degradation. Compare the instantaneous concentration with the lower limit and upper limit of the existence quantity of the precursor gas of degradation. When the instantaneous concentration is greater than or equal to the lower limit and less than or equal to the upper limit, the instantaneous concentration is taken as the effective existence quantity of the precursor gas of degradation. Otherwise, the effective existence quantity of the precursor gas of degradation is recorded as zero, and the effective existence quantities of all precursor gases of degradation are combined into an existence quantity vector.

9. The method for monitoring the deterioration of kiwifruit during storage based on gas composition analysis according to claim 8, characterized in that: S5 also includes: S5-3. Perform degradation risk calculation on the existence vector. Multiply the effective existence quantity of each degradation precursor gas in the existence vector with the corresponding preset risk coefficient and sum them to obtain the degradation risk value. Compare the degradation risk value with the preset first risk threshold and second risk threshold. When the degradation risk value is less than the first risk threshold, the kiwifruit storage space is calculated as the first degradation risk state. When the degradation risk value is greater than or equal to the first risk threshold and less than the second risk threshold, the kiwifruit storage space is calculated as the second degradation risk state. When the degradation risk value is greater than or equal to the second risk threshold, the kiwifruit storage space is calculated as the third degradation risk state.

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