33results about How to "Low detectability" patented technology

The invention provides a phased-array antenna subarray for circularly polarized wide-angle scanning, and aims at providing a phased-array antenna subarray which has a good wide-angle scanning gain characteristic and a good wide-angle scanning circular polarization characteristic, and can avoid derotation properly. The phased-array antenna subarray is achieved by the technical scheme as follows: three circularly polarized microstrip antenna radiation patches are distributed on a microstrip antenna dielectric plate (10) in a ternary rotary inversion subarray form; a metal layer (6) at the lower part of the microstrip antenna dielectric plate serves as a metal place for three microstrip antenna units; each coaxial joint inner core (3) and each coaxial joint outer core (4) form a coaxial feeding port; each coaxial outer core is connected with the metal place; each coaxial joint inner core is connected with the corresponding radiation patch located in the microstrip antenna dielectric plate in blind-inserting and non-contact manners; and the coaxial feeding ports perform electromagnetic coupling feeding and implement phase compensation on the microstrip antenna units to obtain a subarray radiating left-hand circular polarization electromagnetic waves or a subarray radiating right-hand circular polarization electromagnetic waves.

The invention relates to an aptamer electrochemical biosensor, as well as a preparation method and application therof. The preparation method comprises the following steps: (1) respectively dissolving DNA sequences into a PBS buffer solution; (2) firstly polishing and washing a gold electrode; (3) dispensing the buffer solution containing a probe S1 and a probe S2 onto the gold electrode for culturing; (4) dispensing the PBS buffer solution onto an S2-S1 / GE electrode for culturing; (5) placing S2-S2 / GE into the PBS buffer solution to be cultured; washing the electrode to obtain a Aptasensor; (6) culturing the acquired Aptasensor in the buffer solution, and thus obtaining a decorative electrode HP2-HP1-Aptasensor of a super-sandwiched structure by virtue of DNA hybrid chain reaction; and (7) culturing the HP2-HP1-Aptasensor in the buffer solution to obtain a silver nano-cluster decorated electrode AgNCs / HP2-HP1-Aptasensor. According to the preparation method of the biosensor, the used nano material is simple to synthesize, the energy consumption is low, the cost is low, the biological compatibility is good, the mimic enzyme catalytic activity of the nano material is studied and used as an electrochemical detection signal; moreover, a signal detected by the prepared biosensor is amplified by utilizing the DNA hybrid chain reaction.

The invention teaches a system and method for cooperatively networking digital chaos transmissions. The invention involves using generated digital chaos sequences as spreading sequences at a transmitside, receiving the spreaded signals at a receive side and despreading the signal, recovering signals at the receive side, and comparing a stored replica of the digital chaos spreading codes with thedigital chaos spreading codes used at the transmit side to, determine if the signals belong to predefined groups based on predetermined criteria, and forward the signals to a group member based on itsgroup member assignment.

The invention belongs to the technical field of application of fluorescent carbon nano materials and provides preparation of carbon quantum dots based on coal tar asphalt and a detection method for HCHO. The preparation method includes the steps of adding the coal tar asphalt to deionized water and performing ball milling and ultrasonic dispersion treatments to produce the carbon quantum dot dispersion liquid, wherein the mass ratio of the coal tar asphalt to hydrogen peroxide is 1:30-100; and performing H2O2 oxidization, high-speed centrifugation and vacuum drying to the carbon quantum dot dispersion liquid to produce carbon quantum dot powder. The method employs low-cost raw materials and is simple and green and pollution-free. The carbon quantum dots have good water solubility and have uniform particle size distribution, average size being about 3 nm. Selective detection on HCHO is achieved. The carbon quantum dots are low in detection limit on the HCHO, which is 0-50 [mu]M. Change between fluorescent intensity and concentration of HCHO has excellent linear relationship. The detection limit is lower than 1 ppb and high detection precision is achieved.

The invention discloses an organic bionic material and a preparation method. The organic bionic material is prepared from the following components in parts by weight: 1 to 8 parts of polyvinyl alcohol, 1 to 7 parts of metal chloride, 2 to 6 parts of colouring agent, 2 to 9 parts of cross-linking agent, and 5 to 6 parts of catalyst. The organic bionic material can simultaneously simulate plant leaf transpiration and a spectral reflection characteristic, and can simulate plant appearance, spectral reflection so as to achieve the aims of infrared, spectral imaging camouflage and woodland background visual camouflage.

The invention discloses a method for determining the activity of xylanase, which is characterized by comprising: A, producing a standard corresponding relation curve between an absorbance value of xylose measured by an MBTH method and concentration of the xylose; and B, using the MBTH method to detect the absorbance value which is produced after the xylanase to be tested hydrolyzes xylan and is equivalent to that of the xylose; and determining the content of reducing sugar which is produced in unit time and is equivalent to the xylose in an enzymolysis product of the xylanase to be tested according to the standard corresponding relation curve which is produced in step A between the concentration of the xylose and the measured absorbance value of the xylose to calculate the activity of the xylanase. The method uses the MBTH method to detect the quantity of terminal groups of the xylose produced after the xylanase hydrolyzes the xylan to determine the activity of the xylanase. The detectability and work concentration range of xylose determination by the method are apparently lower than those of a DNS method and a potassium ferricyanide method, so the sensitivity of the method is apparently higher than that of the DNS method and the potassium ferricyanide method.

The invention relates to a foldable coaxial reverse propeller unmanned aerial vehicle and a striking method. The unmanned aerial vehicle comprises a data chain antenna, an upper rotor wing, an upper rotor wing propeller clamp, a driving module, a lower rotor wing propeller clamp, a lower rotor wing, a power and flight control module, an image load, a terminal-sensitive bullet, and a terminal-sensitive bullet sensor. The upper rotor wing and the lower rotor wing are connected with the driving module through the upper rotor wing propeller clamp and the lower rotor wing propeller clamp respectively, and the upper rotor wing and the lower rotor wing are driven to rotate under the driving of the driving module to produce lift force; the power and flight control module provides power for the driving module, and the data chain antenna is electrically connected to the power and flight control module to realize the data and instruction transmission between the power and flight control module and a ground control station; and the image load is installed on the outer side of the power and flight control module to be used for collecting an image of an attack target, and the terminal-sensitivebullet and the sensor used for sensitive attack targets are installed at the bottom of the unmanned aerial vehicle. According to the unmanned aerial vehicle and the striking method, the terminal-sensitive bullet is adopted for striking, so that the requirement of a flying platform on the bullet throwing precision is reduced, and low cost is realized.

The invention discloses a magnetic metal-organic nanometer core-shell material with an adjustable diameter and a preparation method thereof. The method comprises the following steps: adding 4,4'-bipyridine into an AgNO3 solution, carrying out uniform mixing under stirring, then adding 1,2,3-benzenetricarboxylic acid, adding KOH to adjust a pH value, carrying out a reaction at 140 DEG C to 170 DEGC so as to obtain an Ag-based metal-organic nanotube material, adding Fe3O4 with a surface modified by silane and the Ag-based metal-organic nanotube material into water, carrying out uniform ultrasonic dispersion, and adding 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine so as to prepare the magnetic metal-organic nanometer core-shell material. According tothe invention, through adjustment of the pH value, adjustment and control of the diameter and specific surface area of the material are achieved, and a maximum specific surface area can reach 177.42 m<2> / g; the contact area between an adsorbent and a trihalomethane pollutant is significantly improved; the effect of adsorption is effectively improved; the removal efficiency of adsorption reaches 90% or more; and the adsorbent can be recycled.

The invention discloses a SNP marker for Konosirus punctatus, and a screening method and application thereof. The screening method for the SNP marker of Konosirus punctatus comprises the following steps: extraction of genomic DNAs; construction of a RAD library and high-throughput sequencing; filtering of original sequence data; and detection and screening of SNP information sites. The addition ofcircular DNAs and chitin in the extraction process of the genomic DNAs can effectively improve the screening accuracy and acquisition efficiency of the SNP marker. The SNP marker obtained by using the method can provide an important basis for related research on the analysis of the population genetic variation level and population genetic structure of Konosirus punctatus. The screening method foracquiring the SNP marker site of Konosirus punctatus has the advantages of high throughput, low cost, high screening accuracy of the SNP marker, high acquisition efficiency, etc.

The invention discloses a gold nanoparticle / cerium dioxide quantum dot co-modified graphite phase carbon nitride nanosheet composite material as well as a preparation method and application thereof. The composite material comprises a cerium dioxide quantum dot loaded graphite phase carbon nitride nanosheet and gold nanoparticles modified on the cerium dioxide quantum dot loaded graphite phase carbon nitride nanosheet, the graphite-phase carbon nitride nanosheet loaded with the cerium dioxide quantum dots takes a graphite-phase carbon nitride nanosheet as a carrier, and the cerium dioxide quantum dots are loaded on the graphite-phase carbon nitride nanosheet. The preparation method comprises the step of modifying the gold nanoparticles on the carrier. The composite material disclosed by the invention has the advantages of strong photoelectric capability, high light energy utilization rate, good dispersion performance, high stability and the like, can be widely used for detecting and degrading pollutants in the environment as a functional material, and has very high use value and application prospect. The preparation method of the composite material has the advantages of being simple in process, convenient to operate, low in cost, free of additional chemical auxiliary solvents and the like, is suitable for large-scale preparation and is beneficial to industrial application.

The invention discloses a mechanical-pneumatic composite thrust vectoring nozzle with a short-distance / vertical take-off and landing functions. The mechanical-pneumatic composite thrust vectoring nozzle comprises a pneumatic steering section and a mechanical steering section. The pneumatic steering section comprises an axisymmetric / quasi-axisymmetric throat offset type pneumatic thrust vectoring nozzle and a transition section. The mechanical steering section comprises a cylinder A, a cylinder B, a bearing A and a bearing B. Along the flow direction of fluid, the cylinder A, the bearing A, thecylinder B, the bearing B, the transition section and an inlet of the axisymmetric / quasi-axisymmetric throat offset type pneumatic thrust vectoring nozzle are connected in sequence. Through relativerotation of the two bearing mechanisms and the pneumatic steering effect of the throat offset type pneumatic thrust vectoring nozzle, the function that airflow deflection exceeds 90 degrees under thecondition that a mechanical structure does not deflect by 90 degrees is achieved, attitude control can be conducted through the pneumatic thrust vectoring nozzle in a hovering state, and the continuous change of key parameters such as lift force, thrust and vector angle of a whole exhaust system is assisted. The nozzle has the characteristics of simple structure, relatively few movement mechanismsand the like.

The invention discloses a band stop type frequency selection surface based on a low dielectric meta-material. The band stop type frequency selection surface comprises three layers of polymer medium substrates and air layers which are between two adjacent polymer medium substrate layers, the polymer medium substrates are etched into square aperture structures having different edges, the polymer medium substrates employ low dielectric low loss polymer medium substrates and are prepared to form a continuous period array, and FSS band stop characteristics can be developed and optimized through adjusting square unit structure edges. According to the band stop type frequency selection surface based on the low dielectric meta-material, the low dielectric polymer substrates are employed, any metal material is not contained, and advantages of low loss, high power capacity and low detectability are realized, moreover, band stop characteristics at a microwave band can be realized, simple design is realized, and strong adjustability is realized.

The invention discloses a multi-component content determination method of Miao medicine Laportea bulbifera. The method comprises the following steps: S100, preparation of mixed reference solution, respectively and accurately weighing right amount of reference substances of Gallocatechin, neochlorogenic acid, Epigallocatechin, catechinic acid, chlorogenic acid, Cyclohexanecarboxylic acid, epicatechin, rutin, isoquercitrin, kaempferol-3-0-rutinoside and quercitrin; and simultaneously determining contents of eleven components including the Gallocatechin, the neochlorogenic acid, the Epigallocatechin, the catechinic acid, the chlorogenic acid, the Cyclohexanecarboxylic acid, the epicatechin, the rutin, the isoquercitrin, the kaempferol-3-0-rutinoside and the quercitrin. The method is simple, efficient, highly sensitive and excellent in specificity, and can provide baisis for quality control of Laportea bulbifera medicinal materials. Compared with the ordinary liquid phase, the method has the advantages of being accurate, reliable and highly sensitive, and having lower specificity detection limit and quantification limit, and is more effective in medicinal material component content analysis through a liquid chromatography-mass spectrometry analysis technology.

The invention discloses an analysis method for detecting impurities in aspartate ornithine and belongs to the field of analytical chemistry. The analysis method comprises the following steps: by usingliquid chromatography, under the conditions that an amino bonded silica gel filling agent, namely Thermo APS-2 of 4.6 mm*250 mm*5 [mu]m, is adopted, 0.1 mol / L monopotassium phosphate buffer solution-acetonitrile (35:65) is used as a mobile phase A, 0.1 mol / L monopotassium phosphate buffer solution-acetonitrile (50: 50) is used as a mobile phase B, a detection wavelength is 200 nm, a flowing speedis 1.0 ml / minute, and a column temperature is 30 DEG C, performing gradient elution, and performing analysis. By adopting the technical scheme, impurities such as 3-amino-2-piperidone, di-poly-l-arginine and an alpha-aspartate biopolymer and an aspartate condensation compound can be rapidly and accurately qualitatively and quantitatively analyzed, a good separation degree can be achieved, a relatively low detection limit and quantitative limit can be achieved, a relatively wide linear range can be achieved, the contents of different impurities can be relatively accurately calculated, and technical support can be provided for further monitoring and studying impurities in the aspartate ornithine.

The invention provides a pedestrian positioning method, a device, a processing device and a storage medium thereof, which relate to the positioning technical field. The method comprises the followingsteps: respectively collecting a head image of a target object by at least two image acquisition devices; inputting a head image into a pre-trained head recognition network; the head features in the image being recognized by the head recognition network, and the head coordinates corresponding to the head features being obtained; matching head features corresponding to at least two image acquisition devices; if the matching is successful, the pedestrian three-dimensional reconstruction being performed according to the head coordinates and the coordinates of at least two image acquisition devices. 3-D reconstruction is carried out by using a head image in the embodiment of the present invention, compared with the foot, the head is not easily occluded, the data collection is easy, and the characteristic dimension is smaller, the training convergence is faster, the false detection rate and the missed detection rate are lower, the false positioning caused by the occlusion of the foot can bereduced, the positioning dimension is higher, the robustness is better, and the positioning effect of pedestrians is improved.

The invention relates to preparation and application of a SnO2 nanorod array / reduced graphene oxide composite nanomaterial sensitive to formaldehyde gas. The raw materials used in the preparation method of the material comprise Na2SnO3. 4H2O, absolute ethyl alcohol and water. The preparation method comprises the following steps: (1) forming seed crystals on a reduced graphene oxide substrate; (2)preparing a hydrothermal synthesis precursor reaction solution; (3) putting apolytetrafluoroethylene lining filled with the precursor solution into a miniature reaction kettle for reaction; and (4) repeatedly cleaning a reaction deposition product with deionized water and absolute ethyl alcohol, separating acleaned sample, and drying to obtain a finished product. The raw materials of sodium stannate (Na2SnO3. 4H2O),solvent absolute ethyl alcohol, and water ratio andseed crystal oriented treatment technology are irreplaceable. The SnO2 nanorod array / reduced graphene oxide composite nanomaterialdisclosed by the invention can be used as a gas sensitive material, and particularly has a high-sensitivity outstanding effect on formaldehyde gas.

The invention provides a DC voltage-stabilized power supply. An inductor L, a fly-wheel diode D, a load resistor R1, a load resistor R2, a load resistor R3, a load resistor R4 and a load resistor R0 are sequentially connected in series between positive and negative electrodes of a power supply Vin, and the negative electrode of the power supply Vin is grounded; a Q end of a pulse width modulation controller is connected with a grid of a switching tube M, a detecting end detecte1 is connected with a rear end of the load resistor R3, and a detecting end detecte2 is connected with a source of the switching tube M and then connected with a rear end of the load resistor R4; and a drain of the switching tube M is connected with a rear end of the inductor L. The DC voltage-stabilized power supply has the advantages of very high conversion efficiency, low operating voltage, undercurrent and overcurrent detection, power-saving mode control and the like, provides biasing for internal operating points through a bandgap reference voltage source, greatly improves the stability of system, increases power supply voltage fluctuation resistance, and improves suppression of interference caused by temperature change and noise.

The invention discloses a rotary vertical take-off and landing spray pipe based on a quasi-axisymmetric throat offset type pneumatic vectoring spray pipe and a design method of the rotary vertical take-off and landing spray pipe. The rotary vertical take-off and landing spray pipe comprises a fixed cylinder section, a first rotary cylinder section and a second rotary cylinder section. The front end of the first rotary cylinder section can be rotationally connected relative to the tail portion of the fixed cylinder section, and is connected with the actuating end of a first rotary driving mechanism. The front end of the second rotary cylinder section can be rotationally connected relative to the tail portion of the first rotary cylinder section, and is connected with the actuating end of asecond rotary driving mechanism. In a level flight mode, an inner flow channel of the spray pipe is of a typical double-throat structure of the quasi-axisymmetric throat offset type pneumatic vectoring spray pipe, and active and passive pneumatic disturbance or mechanical disturbance is carried out near a first throat. In a vertical take-off and landing mode, through rotation of the first rotary cylinder section and the second rotary cylinder section, an outlet of the spray pipe is made to incline downwards, and under the application of disturbance near the first throat, airflow at the outletof the spray pipe is steered by 90 degrees or above.

The invention discloses a kit for detecting a bis-cysteine related substance, which comprises an amino derivatization reagent solution and a related substance standard solution, and the related substance standard solution comprises a cysteine standard solution. The invention also discloses application and a use method of the kit. Reagents adopted by the kit are simple and easy to obtain, the kit is simple and easy to implement when being used for detecting related substances in bicysteine, the detection result is high in accuracy, precision and stability, meanwhile, the kit has very high system applicability and specificity, and the detection limit and the quantitation limit are low.

The method comprises the following steps: obtaining a sample to be detected with a target component of butyrohydrazide to be detected, adopting maleic acid as an internal standard, dissolving the maleic acid and the sample to be detected in deuterated water D2O to obtain a solution to be detected, optimizing test parameters of a wavelength dispersive spectrometer for nuclear magnetic resonance analysis, and determining the content of the butyrohydrazide in the wavelength dispersive spectrometer according to the content of the butyrohydrazide in the wavelength dispersive spectrometer. The method comprises the following steps: measuring the nuclear magnetic resonance hydrogen spectrum of a to-be-measured solution to obtain the quantitative peaks of maleic acid and butyrohydrazide, respectively integrating the quantitative peaks of maleic acid and butyrohydrazide to obtain integral areas S maleic acid and S butyrohydrazide, and calculating the content of butyrohydrazide in the to-be-measured sample according to a formula. According to the method, a derivatization step is not needed, and complicated purification processes such as extraction and filtration are not needed, so that the test process can be greatly simplified, a new thought can be provided for determining the compounds by a quantitative nuclear magnetic resonance technology, and the application range of the quantitative nuclear magnetic resonance technology is expanded.

The invention discloses an aluminothermic reduction ceria octahedral material and its preparation method and application. The material has an octahedral single crystal structure, exposes (111) crystal faces, contains oxygen vacancies on the surface, and covers the surface of the octahedral single crystal structure. 1~2nm amorphous layer, the amorphous layer contains oxygen vacancies and Ce 3+ . The preparation method is as follows: adopting a hydrothermal method to prepare octahedral ceria nanocrystals, and performing aluminothermic reduction treatment on octahedral ceria nanocrystals. The material provided by the invention is used to prepare electrodes, has high catalytic activity, high sensitivity, wide linear range, good stability and high selectivity, and the material is proved to be suitable for H in real samples 2 o 2 The detection error is extremely low, which can meet the needs of practical applications.

The invention discloses a pretreatment method for detecting the content of phenolic impurities in a sample. The method comprises the following steps: weighing the sample, putting the sample into a volumetric flask, adding an acetonitrile solution of vitamin C, dissolving the sample, uniformly shaking, fixing the volume by using a formic acid solution of the vitamin C, filtering, and carrying out instrumental analysis on filtrate, wherein the content of the vitamin C in the acetonitrile solution of the vitamin C and the formic acid solution of the vitamin C is 90-110 [mu]g / ml. By adopting the pretreatment method disclosed by the invention, extremely low detection limit and quantitation limit can be achieved in phenol impurity detection, and the repeatability is good; the stabilizing time of the reference substance solution can be prolonged to 30 hours, the stabilizing time of the standard recovery solution can be prolonged to 11 hours, meanwhile, the vitamin C and the phenol target object can be effectively separated in a corresponding chromatographic system, and the determination of the target compound is not interfered.

The invention belongs to the field of heavy metal ion detection, and particularly relates to a method for high-sensitivity detection of mercury ions by using a novel Au / C nano-composite sensor. Comprising the steps that a dispersion solution is prepared through ultrasonic concussion, a chloroauric acid solution and a sodium borohydride solution are added into the dispersion solution, gold ions contained in the chloroauric acid solution are reduced into gold nanoparticles, and Au / C nanoparticles are prepared; adding a to-be-detected cosmetic solution into the Au / C nanoparticle solution, judging whether the to-be-detected cosmetic solution contains mercury ions or not by observing the color change of the Au / C nanoparticle solution, and judging the content of the mercury ions by using a colorimetric method. The method has portability on mercury ion detection and is extremely important in household detection, the novel Au / C nano-composite sensor is constructed for colorimetric detection of mercury ions for the first time, and the detection line and the detection range are relatively low. The method for detecting the heavy metal element mercury ions is supplemented again, and certain practical significance is achieved.

The invention provides a multipurpose ship capable of carrying aircrafts, comprising a deck platform and a buoyancy cabin. Buoyancy cabins are arranged under the deck platform, and three buoyancy cabins are arranged under the deck platform in parallel; The buoyancy cabin is fixedly connected with the bottom of the deck platform through a keel; An aircraft runway is arranged along the upper surfaceof the deck platform, and an aircraft take-off and landing platform and an ejector are arranged at one or both ends of the aircraft runway; The interior of the deck platform is divided into one-story, two-story or three-story compartments, which are set as equipment compartments or hangars. The invention has the advantages of high speed, strong firepower, low detectability, and more emphasis on collocation with various carrier-based aircraft, and can be built in batches to quickly form combat effectiveness.

The invention relates to the field of food and agricultural safety detection, in particular to the design and synthesis of a coumarin-based fluorescent derivative reagent with novel structure and its application in the detection of fipronil. Tests have proved that the coumarin-based fluorescent derivative reagent designed and synthesized by the present invention has strong fluorescence intensity, and the HPLC-FLD method for determining fipronil based on the pre-column derivatization established by the derivative reagent has high sensitivity and low detection limit. and low limit of quantification, good stability and reproducibility, the method is applied to the detection of fipronil residues in eggs, the results are accurate and reliable, and are superior to the currently reported HPLC-MS / MS and GC-MS methods. The coumarin-based fluorescent derivatization reagent designed and synthesized by the present invention has excellent performance, and the pre-column derivatization detection method of fipronil based on it is sensitive, reliable and accurate, and has a good application prospect.

The invention relates to a method and a kit for detecting fragile X syndrome mutation. The kit comprises the following reagents: (1) a reagent for long fragment PCR amplification; (2) a reagent for PCR amplification of a high GC region; and (3) a reagent for constructing a third-generation sequencing library. The method comprises the following steps: (1) obtaining a sample of a subject; (2) carrying out long fragment PCR (Polymerase Chain Reaction) amplification and high GC PCR amplification on the sample; (3) constructing a third-generation sequencing library; and (4) sequencing and analyzing the FMR1 gene mutation type.

The invention discloses a florfenicol rapid detection method. The method comprises the following steps: 1, carrying out pretreatment, cleaning a sample, and extracting an organic solvent; and 2, adding 5ml of acetonitrile ethyl acetate into the extracting solution of the organic solvent, fully oscillating for about 30 seconds, oscillating by using a vortex oscillator, adding 10ml of ethyl acetate,uniformly mixing for 2 minutes in a vortex manner, and centrifuging for 5 minutes at the speed of 5000r / min. According to the florfenicol rapid detection method, a large amount of fat and other endogenous interferents are removed by washing hydrolysate with ethyl acetate in s sample pretreatment process; and the method has the advantages of substantial improvement of an anti-interference abilityof the detection method on other substances in a pig edible tissue, reduction of the detection cost, reduction of the use amount of an organic solvent, a reliable quantitative analysis result, and suitableness for daily monitoring of florfenicol total residues in the pig edible tissue by basic detection units, and quantification by an internal standard method.