A water area upconversion fluorescence vortex detection device and detection method thereof

Abstract

The present invention provides a water area upconversion fluorescence vortex detection device and a detection method thereof. The device includes a housing, a laser transmitter, a nanoparticle storage bin and an image acquisition and processing system. The laser transmitter emits an infrared laser to irradiate the intended detection direction; the nanoparticle storage bin emits a projectile filled with hydrophilic upconversion nanopowder to the intended detection direction, and the projectile explodes in a designated area to release upconversion nanoparticles; the upconversion nanoparticles emit visible light under the excitation of an infrared laser beam to present an optical image; the image acquisition and processing system collects the optical image, which is used to determine the turbulence condition of the water area after processing. The present invention can achieve the effect of integrating a signal transmitting and receiving device and visualizing underwater turbulence, which is beneficial to improving the accuracy and sensitivity of turbulence visualization imaging and enhancing the detectability of vortices.

Description

Technical Field

[0001] The present invention relates to the technical field of water turbulence detection, and in particular to a water upconversion fluorescence vortex detection device and a detection method thereof. Background Art

[0002] Turbulence is a phenomenon common in oceans and lakes, characterized by a localized, non-uniform distribution of seawater density and concentration. Turbulence occurs at scales ranging from millimeters to tens of kilometers. Ocean turbulence changes rapidly and randomly within small areas and short periods of time. For untowed vehicles, encountering turbulent waters can easily lead to violent collisions with hard objects such as underwater reefs, causing damage. Therefore, detecting turbulence in waters is crucial for submersibles, especially untowed intelligent submersibles, to adjust their course in a timely manner, improving navigation safety and stability.

[0003] At present, the detection of targets in water environments mainly relies on ultra-long wave detection and acoustic wave detection. However, ultra-long wave detection has disadvantages such as complex system, high power consumption, and narrow passband, while the disadvantages of slow acoustic wave transmission speed, long delay, severe Doppler dispersion, and poor confidentiality are also inevitable. In this context, underwater optical detection methods provide new ideas for detection technology. At present, the research on underwater turbulence optical detection mainly focuses on vortex beam detection and particle imaging technology. After analysis, the common problem of the aforementioned optical detection methods is that the detection signal sending device and the feedback signal receiving device must be distributed in different directions of the detected area and cannot be installed on the same carrier (such as an aircraft). Therefore, it is impossible to apply to the aircraft body and complete real-time autonomous detection and risk avoidance. In addition, the existing optical detection process requires the use of optical accessories such as mirrors to change the propagation direction of the light beam multiple times. The required equipment is bulky and the detection sensitivity is low. Summary of the Invention

[0004] In response to the aforementioned shortcomings of ultra-long wave detection, such as system complexity, high power consumption, and narrow passband; shortcomings of acoustic wave detection, such as slow transmission speed, long delay, severe Doppler dispersion, and poor confidentiality; and technical problems encountered by optical detection methods in water turbulence detection, such as bulky equipment, unrealistic signal transmission and information reception, and different bodies, a water area upconversion fluorescence vortex detection device and detection method are provided. The present invention primarily achieves "turbulence visualization" by exciting upconversion luminescent particles with infrared lasers, and performs image acquisition and comparative analysis of the water area's self-luminous optical images.

[0005] The technical means adopted in the present invention are as follows:

[0006] A water area upconversion fluorescence vortex detection device, installed on a vehicle, comprises: a housing, a laser emitter encapsulated in the housing, a nanoparticle storage bin, and an image acquisition and processing system, wherein the nanoparticle storage bin, the laser emitter, and the image acquisition and processing system are arranged in sequence from top to bottom;

[0007] The laser emitter and the nanoparticle storage bin are both connected to an image acquisition and processing system. The laser emitter is used to emit an infrared laser for irradiation in the intended detection direction; the nanoparticle storage bin is used to launch a projectile containing hydrophilic upconversion nanopowder in the intended detection direction. The projectile explodes in a designated area to release upconversion nanoparticles. The upconversion nanoparticles are within the irradiation range of the infrared laser and emit visible light under the excitation of the infrared laser beam to present an optical image. The image acquisition and processing system is used to collect optical image data, and through processing and display, use it to determine the turbulence conditions of the water area.

[0008] The image acquisition and processing system includes an image acquisition module, an image processing module and an image display module. The image acquisition module is connected to the laser emitter and the nanoparticle storage bin at the same time and is used to acquire optical image data. The image processing module is connected to the image acquisition module and the image display module respectively through a network cable and is used to receive the original optical image data acquired by the image acquisition module, perform image enhancement processing on the data, and transmit the processed image to the image display module for display.

[0009] Furthermore, the nanoparticle storage bin is arranged 1 cm away from the top of the shell.

[0010] Furthermore, the laser emitter is arranged 1.5 cm below the nanoparticle storage bin, emits infrared laser at a depression angle of 5°, and expands the beam through a beam expander.

[0011] Furthermore, the image acquisition and processing system is arranged 2 cm below the laser emitter and 1 cm away from the bottom of the housing.

[0012] Furthermore, the image acquisition and processing system adopts an integrated hardware acquisition and processing design scheme, and the image acquisition and processing tasks are implemented by the same hardware board. The data exchange between the two is realized through the on-board bus (or other data communication methods, such as FIFO, dual RAM alternation, etc.). Image acquisition is completed by a dedicated digital conversion module, and image processing is implemented by a dedicated DSP (or DSP array) module. The modules adopt a tightly coupled integrated design.

[0013] The present invention also provides a detection method for a water area upconversion fluorescence vortex detection device, comprising the following steps:

[0014] Step 1: The laser transmitter on board the spacecraft emits an infrared laser at a 5° depression angle in the direction to be detected;

[0015] Step 2: Simultaneously, the spacecraft's nanoparticle storage chamber launches a projectile containing hydrophilic upconversion nanopowder in the intended detection direction. The projectile explodes in the designated area, releasing the upconversion nanoparticles.

[0016] Step 3: The upconversion nanoparticles emit visible light under the excitation of the infrared laser beam, presenting an optical image;

[0017] Step 4: The image acquisition and processing system carried by the vehicle collects optical images, which are used to determine the turbulence conditions of the water area after processing; wherein, after the laser emitter and the nanoparticle storage bin simultaneously emit laser searchlight and up-convert nanopowder projectiles, the image acquisition module is triggered to collect optical image data, and the optical image data is transmitted to the image processing module, which performs image enhancement processing on the optical image data and transmits it to the image display module for display.

[0018] Furthermore, in step one, the method for the laser transmitter carried by the aircraft to emit an infrared laser in the direction to be detected for irradiation is as follows: when the aircraft reaches unknown waters, the laser transmitter carried by the aircraft emits an 808nm infrared laser in the direction to be detected at a depression angle of 5°, and irradiates forward after beam expansion.

[0019] Furthermore, in step 2, a projectile containing hydrophilic upconversion nanopowder is launched from the nanoparticle storage compartment of the spacecraft toward the intended detection direction, and the projectile explodes in a designated area. The method for releasing the upconversion nanoparticles is as follows: a projectile containing hydrophilic upconversion nanopowder is launched from the nanoparticle storage compartment of the spacecraft toward the intended detection direction, and the projectile explodes in the designated area, releasing the upconversion nanoparticles, which rapidly diffuse in the local area to form a sol;

[0020] The upconversion nanopowder includes but is not limited to NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2、NaGdF4:Yb 3+ ,Er 3+ @NaGdF4@PDAs、BaGdF4:Yb 3+ ,Er 3+ 、NaYF4:Yb 3+ ,Er 3+ @NaYF4:Yb 3+ ,Nd 3+ @PDAs、NaYbF4:Er 3+ @NaYbF4:Tm 3+@NaYF4、NaYF4:Yb 3+ ,Tm 3+ @CaF2、NaYF4:Yb 3+ ,Tm 3+ ,Ce 3+ 、NaLuF4:Yb 3+ ,Tm 3+ ,Er 3+ 、NaLuF4:Yb 3+ ,Tm 3+ or Gd2O3:Yb 3+ ,Ho 3+ wait.

[0021] Furthermore, in the step three, the upconversion nanoparticles emit visible light under the excitation of an infrared laser beam, and the method for presenting an optical image is: the upconversion nanoparticles emit different colors of light under the excitation of an 808nm infrared laser beam, and by adjusting the doping ion type and doping concentration ratio of the upconversion nanopowder, modulation of different colors of light and different luminous intensities in the visible light range can be achieved; the vortex structure generated by turbulence will carry the upconversion nanoparticles to form a random spatial distribution, while in a static water environment a relatively stable distribution state will be formed, and the distribution state of the nanocolloidal particles will present a static or dynamic optical image, reflecting the vortex structure of the water area.

[0022] Furthermore, in step four, the image acquisition and processing system carried by the aircraft collects optical images, and the method for determining the turbulence conditions of the water area after processing is as follows: the optical image is a self-luminous phenomenon, and the image acquisition module carried by the aircraft collects the optical image of the nano-colloidal particles of the unknown water area. The image processing module enhances the image with the Soble operator based on the motion compensation principle. After the image display module displays it, it compares the distribution of the optical image of the still water environment in the image database to determine the turbulence degree of the water body.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The water area upconversion fluorescence vortex detection device and detection method provided by the present invention can achieve the purpose of "integration" of signal transmitting and receiving devices and "visualization" of underwater turbulence by collecting, processing and analyzing the specific self-luminous images presented by upconversion nanoparticles along the vortex water flow, thereby solving the problems commonly existing in the existing technology that the signal transmitting and receiving devices of the detection system are different in body and the feedback signal is difficult to transmit to the navigation equipment body.

[0025] 2. The water area upconversion fluorescence vortex detection device and detection method provided by the present invention use hydrophilic upconversion nanoparticles as luminescent materials and utilize their good monodispersity in water bodies to help improve the accuracy and sensitivity of turbulence "visualization" imaging.

[0026] 3. The water area upconversion fluorescence vortex detection device and detection method provided by the present invention comprehensively consider the absorption spectrum of water and minimize luminescence loss by selecting the combined upconversion luminescence mechanism of "808nm excitation-550nm emission", which helps to improve the stability of underwater optical detection technology and enhance its detectability.

[0027] In summary, the application of the technical solution of the present invention can solve the problems existing in the existing underwater optical detection technology, such as the detection system signal transmitting and receiving devices are different bodies, the feedback signal is difficult to transmit to the navigation equipment body, the detection equipment is bulky, the detection means are complicated, and the detection sensitivity is low.

[0028] Based on the above reasons, the present invention can be widely promoted in the fields of ships, water vehicles, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 This is a diagram of the integrated vortex detection device of the present invention.

[0031] Figure 2 Schematic diagram of the detection method of the present invention.

[0032] Figure 3 TEM image of the core nanoparticles of the present invention.

[0033] Figure 4 TEM image of the core-shell nanoparticles of the present invention.

[0034] Figure 5 This is the luminescence intensity spectrum of the core-shell nanoparticles of the present invention.

[0035] Figure 6 This is the energy level diagram of the core-shell nanoparticles of the present invention.

[0036] Figure 7 TEM image of the core-shell nanoparticles after hydrophilic modification of the present invention. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0041] Example 1

[0042] like Figure 1 As shown, the present invention provides a water area upconversion fluorescence vortex detection device. This device, based on upconversion luminescence and optical principles, is installed on a vehicle and includes a housing, a laser emitter, a nanoparticle storage chamber, and an image acquisition and processing system. The image acquisition and processing system includes an image acquisition module, an image processing module, and an image display module.

[0043] The laser transmitter is connected to the image acquisition module and emits infrared laser in the direction to be detected.

[0044] The nanoparticle storage chamber is connected to the image acquisition module, which launches a projectile filled with hydrophilic upconversion nanopowder in the intended detection direction. The projectile explodes in the designated area and releases upconversion nanoparticles.

[0045] After the laser emitter and the nanoparticle storage bin simultaneously launch the laser searchlight and the upconversion nanopowder projectile, the image acquisition module is triggered to collect the optical image data presented by the upconversion nanoparticles emitting visible light under the excitation of the infrared laser beam.

[0046] One end of the image processing module is connected to the image acquisition module through a network cable, which is used to receive the original optical image data and perform image enhancement processing on it; the other end is connected to the image display module, which transmits the processed image to the image display module for display.

[0047] The installation locations of the image acquisition and processing system, laser transmitter, and nanoparticle storage bin are as follows:

[0048] The nanoparticle storage chamber, laser emitter, and image acquisition and processing system are encapsulated in the same housing to form an integrated vortex detection device. The nanoparticle storage chamber, laser emitter, and image acquisition and processing system are arranged in sequence from top to bottom on the same vertical line. The specific location information and design factors are as follows:

[0049] Considering that upconversion nanopowder particles in aquatic environments may experience localized aggregation due to gravity and internal vortexes within the fluid, leading to a tendency to sink, a nanoparticle storage bin was placed at the very top, 1 cm from the top of the upper shell of the housing. An 808nm laser emitter was positioned 1.5 cm directly below the nanoparticle storage bin, emitting infrared laser light at a 5° angle of depression, which was then expanded by a beam expander. Considering that the high power of the emitted laser light could have a certain impact on the image acquisition and processing system, an image acquisition and processing system was installed 2 cm directly below the laser emitter to capture data from the self-luminous imaging of the upconversion nanoparticles under infrared irradiation. The image acquisition and processing system was positioned 1 cm from the bottom of the lower shell of the housing.

[0050] Example 2

[0051] like Figure 2 As shown, based on Example 1, the present invention provides a detection method for a water area upconversion fluorescence vortex detection device, comprising the following steps performed in sequence:

[0052] 1) The laser transmitter carried by the spacecraft emits infrared laser in the direction to be detected.

[0053] 2) The spacecraft's internal magazine (nanoparticle storage compartment) launches a projectile containing hydrophilic upconversion nanopowder in the intended detection direction. The projectile explodes in the designated area, releasing upconversion nanoparticles.

[0054] 3) The upconversion nanoparticles emit visible light under the excitation of the infrared laser beam, presenting an optical image.

[0055] 4) The image acquisition and processing system carried by the aircraft collects optical images, which are then processed to determine the turbulence conditions in the water area.

[0056] In this embodiment, the method in which the laser transmitter carried by the aircraft in step 1) emits an infrared laser in the direction to be detected for irradiation is as follows: when the aircraft reaches unknown waters, the laser transmitter carried by the aircraft emits an 808nm infrared laser in the direction to be detected, and irradiates forward after beam expansion.

[0057] In this embodiment, the internal magazine of the aircraft described in step 2) launches a projectile containing hydrophilic upconversion nanopowder in the direction to be detected, and the projectile explodes in a designated area to release the upconversion nanoparticles. The method is as follows: the internal magazine of the aircraft launches a projectile containing hydrophilic upconversion nanopowder in the direction to be detected, and the projectile explodes in the designated area, releasing the upconversion nanoparticles, and rapidly diffuses in the local area to form a sol. Upconversion nanopowders include but are not limited to NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2、NaGdF4:Yb 3+ ,Er 3+ @NaGdF4@PDAs、BaGdF4:Yb 3+ ,Er 3+ 、NaYF4:Yb 3+ ,Er 3+ @NaYF4:Yb 3+ ,Nd 3+ @PDAs、NaYbF4:Er 3+ @NaYbF4:Tm 3+ @NaYF4、NaYF4:Yb 3+ ,Tm 3+ @CaF2、NaYF4:Yb 3+ ,Tm 3+ ,Ce 3+ 、NaLuF4:Yb 3+ ,Tm 3+ ,Er 3+ 、NaLuF4:Yb 3+ ,Tm 3+ or Gd2O3:Yb3+ ,Ho 3+ In this embodiment, the hydrophilic upconversion nanopowder NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2.

[0058] In this embodiment, the upconversion nanoparticles in step 3) emit visible light under the excitation of an infrared laser beam, and the method for presenting an optical image is: the upconversion nanoparticles NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ When excited by an 808nm laser beam, @SiO2 emits bright green light and relatively weak red light, with a green-red light branching ratio of 8.25. The vortex structure generated by turbulence carries the upconversion nanoparticles into a random spatial distribution, while in a still water environment, a more stable distribution is formed. Therefore, the distribution of the nanocolloidal particles will appear as static or dynamic optical images, reflecting the vortex structure of the water.

[0059] In this embodiment, the image acquisition and processing system carried by the aircraft in step 4) collects optical images, and the method for determining the turbulence condition of the water area after processing is as follows: the optical image is a self-luminous phenomenon, and the image acquisition module carried by the aircraft collects the optical image of the nano-colloidal particles of the unknown water area. The image processing module enhances the image with the Soble operator based on the motion compensation principle. After the image display module displays the image, the distribution of the optical image of the still water environment in the image database is compared to determine the turbulence degree of the water body.

[0060] The present invention collects, processes and analyzes the specific self-luminous images presented by upconversion nanoparticles along the vortex water flow, thereby achieving the purpose of "integration" of signal transmission and reception devices and "visualization" of underwater turbulence, and solving the common problems in existing technologies that the signal transmission and reception devices of the detection system are different bodies and the feedback signal is difficult to transmit to the navigation equipment body.

[0061] The present invention adopts hydrophilic NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2 upconversion nanoparticles are used as luminescent materials, and their good monodispersity in water bodies can help improve the accuracy and sensitivity of turbulence "visualization" imaging.

[0062] The present invention comprehensively considers the absorption spectrum of water and minimizes luminescence loss to the greatest extent by selecting a combined up-conversion luminescence mechanism of "808nm excitation-550nm emission", which helps to improve the stability of underwater optical detection technology and enhance its detectability.

[0063] Example 3

[0064] Based on Example 2, the present invention also provides a hydrophilic Nd 3+ The sensitized nanoparticles were prepared using a high-temperature coprecipitation method to prepare monodisperse lanthanide ion-doped NaYF4 upconversion core nanoparticles. Subsequently, an epitaxial growth method was used to coat the core nanoparticles with an inert NaYF4 shell. The specific preparation steps are as follows:

[0065] 1) Synthesis of NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ Core nanoparticles

[0066] (1) At room temperature (23-25°C), use a pipette to pipette 3 ml of OA (oleic acid), 7 ml of ODE (1-octadecene), and 2 ml of Ln(CH3CO2)3 (0.2 M) aqueous solution into a 50 ml two-necked flask (add a high-temperature magnet);

[0067] (2) Place the two-necked flask in an oil bath, set the temperature of the heating device to 130°C, and after the water in the liquid in the two-necked flask is completely evaporated, raise the temperature to 150°C and keep the temperature constant for 60 minutes;

[0068] (3) Stop heating, keep the magneton rotating, and slowly cool the mixed solution to room temperature;

[0069] (4) Move the two-necked bottle into a heating mantle and set the temperature of the heating mantle to maintain the solution temperature at 50°C;

[0070] (5) Use a pipette to draw 2 ml of NaOH (0.5 M) and 4 ml of NH4F (0.4 M) methanol solution into a 15 ml centrifuge tube, cover it tightly, vortex and quickly inject it into two flasks, keep the temperature at 50 °C for 30 min;

[0071] (6) Adjust the temperature of the heating mantle to 110°C to remove methanol from the solution. After the methanol is removed, connect the two-necked flask to the double-row tube;

[0072] (7) Evacuate for 10 minutes, then briefly pass N2, and repeat this three times;

[0073] (8) Adjust the temperature of the heating mantle to raise the temperature of the solution to 290°C (heating rate 10°C / min) and maintain the temperature for 1.5 h. Slowly flow N2 throughout the process.

[0074] (9) Remove the heating mantle, keep the magnet rotating, and allow the solution to cool naturally to room temperature;

[0075] (10) Transfer the mixed solution to a 50 ml centrifuge tube, add 30 ml of ethanol, place in a centrifuge, centrifuge at 8000 rpm for 8 min, and discard the supernatant;

[0076] (11) Add 4 ml of cyclohexane to the centrifuge tube, add 15 ml of ethanol after ultrasonic dispersion, place in a centrifuge, centrifuge at 8000 rpm for 8 min, discard the supernatant, and repeat this step twice;

[0077] (12) Add 4 ml of cyclohexane to the centrifuge tube, transfer the solution to a 5 ml reagent bottle after ultrasonic dispersion, label it, and store it in a refrigerator at 4 °C until use. TEM test confirmed that the sample was a monodisperse nanoparticle with a diameter of about 20 nm. Figure 3 shown.

[0078] 2) Synthesis of NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ core-shell nanoparticles

[0079] (1) At room temperature (23-25°C), use a pipette to pipette 3 ml of OA (oleic acid), 7 ml of ODE (1-octadecene), and 2 ml of Ln(CH3CO2)3 (0.2 M) aqueous solution into a 50 ml two-necked flask (add a high-temperature magnet);

[0080] (2) Place the two-necked flask in an oil bath, set the temperature of the heating device to 130°C, and after the water in the liquid in the two-necked flask is completely evaporated, raise the temperature to 150°C and keep the temperature constant for 60 minutes;

[0081] (3) Stop heating, keep the magneton rotating, and slowly cool the mixed solution to room temperature;

[0082] (4) Move the two-necked bottle into a heating mantle and set the temperature of the heating mantle to maintain the solution temperature at 50°C;

[0083] (5) Use a pipette to draw 4 ml of NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ The cyclohexane solution was transferred to a two-necked flask and heated for 10 min;

[0084] (6) Use a pipette to draw 2 ml of NaOH (0.5 M) and 4 ml of NH4F (0.4 M) methanol solution into a 15 ml centrifuge tube, cover it tightly, vortex and quickly inject it into the two-necked flask, and keep it at 50 °C for 30 min;

[0085] (7) The reaction process is the same as (6)-(12) in Section 1); TEM test shows that the sample diameter increases to about 25nm and is still in a monodisperse state, indicating that the shell coating is successfully achieved (see Appendix Figure 4 ).

[0086] The nanoparticles were tested and showed bright green light emission under the excitation of 808nm infrared laser. The emission spectrum is shown in the attached figure. Figure 5 As shown in Figure 2, the upconversion luminescence of the nanoparticles consists of 520-560nm green light and relatively weak 640-670nm red light emission, and the green-red light branching ratio reaches 8.25. Figure 6 This is the transition energy level diagram of the Er-Yb-Nd-Nd system, which can help analyze the upconversion luminescence process of nanoparticles.

[0087] 3) Synthesis of NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2 hydrophilic modified nanoparticles

[0088] (1) Take NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ Mix 2 ml of 0.1 M sodium phosphate (2 ml, 0.1 M) with 2 ml of 2 M hydrochloric acid, inject into a 50 ml beaker and seal. After ultrasonication at room temperature for 1 h, transfer the reaction solution into a 50 ml centrifuge tube and centrifuge at 10,000 rpm for 5 min. Remove the supernatant and dissolve the precipitate in 2 ml of water (concentration of 0.1 M).

[0089] (2) Take NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+(2ml, 0.1M), add 2.5ml CO-520 and stir for 10min. Add 0.45ml ammonia water (mass fraction 25-28%), seal the container and ultrasonicate for 5min, then add 0.2ml tetraethyl orthosilicate (TEOS). Seal the container again and rotate and stir at 600rpm for 48h. After the reaction is completed, add 50ml acetone, centrifuge at 10000rpm for 5min at room temperature, remove the supernatant, wash the nanoparticles twice with anhydrous ethanol and water (1:1), and precipitate and centrifuge with 50ml acetone again to obtain NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2 was finally dissolved in 2 ml of water (concentration was 0.1 M).

[0090] TEM images of modified core-shell nanoparticles are shown in the attached Figure 7 As shown in the figure, a 10nm thick SiO2 layer can be clearly seen on the surface of the upconversion nanoparticles. After modification, the nanoparticles can be well dispersed in water and will not settle for a long time.

[0091] The present invention can also be applied to fields such as ships and water vehicles, and has potential application prospects and outstanding practical significance in fields such as diving danger warning.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water area upconversion fluorescence vortex detection device, characterized in that: Installed on the aircraft, comprising: a shell and a laser transmitter, a nanoparticle storage bin and an image acquisition and processing system encapsulated in the shell, wherein the nanoparticle storage bin, the laser transmitter and the image acquisition and processing system are arranged in sequence from top to bottom; The laser emitter and the nanoparticle storage bin are both connected to an image acquisition and processing system. The laser emitter is used to emit an infrared laser to irradiate the intended detection direction; the nanoparticle storage bin is used to emit a projectile containing a hydrophilic up-conversion nanopowder to the intended detection direction. The projectile explodes in a designated area to release up-conversion nanoparticles. The up-conversion nanoparticles are within the irradiation range of the infrared laser. The up-conversion nanoparticles emit visible light and present an optical image under the excitation of the infrared laser beam; the image acquisition and processing system is used to collect optical image data, and to determine the turbulence condition of the water area through processing and display; The image acquisition and processing system includes an image acquisition module, an image processing module and an image display module. The image acquisition module is connected to the laser emitter and the nanoparticle storage bin at the same time, and is used to acquire optical image data. The image processing module is connected to the image acquisition module and the image display module respectively through a network cable, and is used to receive the original optical image data acquired by the image acquisition module, perform image enhancement processing on the original optical image data, and transmit the processed image to the image display module for display. The nanoparticle storage bin is arranged 1 cm away from the top of the housing.

2. The water area upconversion fluorescence vortex detection device according to claim 1, characterized in that: The laser emitter is arranged 1.5 cm below the nanoparticle storage bin, emits infrared laser at a depression angle of 5°, and expands the beam through a beam expander.

3. The water area upconversion fluorescence vortex detection device according to claim 1, characterized in that: The image acquisition and processing system is arranged 2 cm below the laser emitter and 1 cm away from the bottom of the housing.

4. The water area upconversion fluorescence vortex detection device according to claim 1, characterized in that: The image acquisition and processing system adopts an integrated hardware acquisition and processing design scheme. The image acquisition and processing tasks are implemented through the same hardware board. The data exchange between the two is realized alternately through the on-board bus, FIFO or dual RAM. Image acquisition is completed by the digital conversion module, and image processing is implemented through the DSP or DSP array module. A tightly coupled integrated design is adopted between the modules.

5. A detection method for the water area upconversion fluorescence vortex detection device according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: The laser transmitter carried by the spacecraft emits an infrared laser at a depression angle of 5° in the direction to be detected; Step 2: At the same time, the nanoparticle storage compartment of the spacecraft launches a projectile containing hydrophilic upconversion nanopowder in the intended detection direction, and the projectile explodes in the designated area to release the upconversion nanoparticles; Step 3: The up-conversion nanoparticles emit visible light under the excitation of the infrared laser beam, presenting an optical image; Step 4: The image acquisition and processing system carried by the vehicle acquires optical images, which are used to determine the turbulence conditions of the water area after processing; wherein, after the laser emitter and the nanoparticle storage bin simultaneously emit infrared lasers and projectiles containing hydrophilic up-conversion nanopowders, the image acquisition module is triggered to acquire optical image data, and the optical image data is transmitted to the image processing module, which performs image enhancement processing on the optical image data and transmits it to the image display module for display.

6. The detection method of the water area upconversion fluorescence vortex detection device according to claim 5 is characterized in that: In the step 1, the method for the laser transmitter carried by the aircraft to emit an infrared laser to irradiate in the intended detection direction is as follows: when the aircraft reaches unknown waters, the laser transmitter carried by the aircraft emits an 808nm infrared laser at a depression angle of 5° in the intended detection direction, and irradiates forward after beam expansion.

7. The detection method of the water area upconversion fluorescence vortex detection device according to claim 5 is characterized in that: In the step 2, the nanoparticle storage bin of the aircraft launches a projectile containing hydrophilic upconversion nanopowder toward the intended detection direction, and the projectile explodes in a designated area. The method for releasing the upconversion nanoparticles is as follows: the nanoparticle storage bin of the aircraft launches a projectile containing hydrophilic upconversion nanopowder toward the intended detection direction, and the projectile explodes in a designated area, releasing the upconversion nanoparticles, and rapidly diffuses in a local area to form a sol; The hydrophilic upconversion nanopowder is NaYF4:Nd 3+ ,Yb 3+ ,Er 3+ @NaYF4:Nd 3+ @SiO2、NaGdF4:Yb 3+ ,Er 3 + @NaGdF4@PDAs、BaGdF4:Yb 3+ ,Er 3+ 、NaYF4:Yb 3+ ,Er 3+ @NaYF4:Yb 3+ ,Nd 3+ @PDAs, NaYbF4:Er 3+ @NaYbF4:Tm 3+ @NaYF4、NaYF4:Yb 3+ ,Tm 3+ @CaF2、NaYF4:Yb 3+ ,Tm 3+ ,Ce 3+ 、NaLuF4:Yb 3+ ,Tm 3+ ,Er 3+ 、NaLuF4:Yb 3+ ,Tm 3+ or Gd2O3:Yb 3+ ,Ho 3+ .

8. The detection method of the water area upconversion fluorescence vortex detection device according to claim 5 is characterized in that: In the step three, the upconversion nanoparticles emit visible light under the excitation of an infrared laser beam, and the method for presenting an optical image is as follows: the upconversion nanoparticles emit different colored lights under the excitation of an 808nm infrared laser beam, and by adjusting the doping ion type and doping concentration ratio of the hydrophilic upconversion nanopowder, modulation of different colored lights and different luminous intensities within the visible light range can be achieved; the vortex structure generated due to turbulence will carry the upconversion nanoparticles to form a random spatial distribution, while in a static water environment a relatively stable distribution state will be formed, and the distribution state of the upconversion nanoparticles will present a static or dynamic optical image, reflecting the vortex structure of the water area.

9. The detection method of the water area upconversion fluorescence vortex detection device according to claim 5, characterized in that: In the step 4, the image acquisition and processing system carried by the aircraft acquires optical images, and the method for determining the turbulence condition of the water area after processing is as follows: the optical image is a self-luminous phenomenon, and the image acquisition module carried by the aircraft acquires the optical image of the up-conversion nanoparticles of the unknown water area condition; the image processing module enhances the optical image of the up-conversion nanoparticles of the unknown water area condition with the Soble operator based on the motion compensation principle; after being displayed by the image display module, the distribution of the optical image of the still water environment in the image database is compared to determine the turbulence degree of the water body.

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