80results about How to "Does not affect detection" patented technology

The invention discloses a time difference type ultrasonic flowmeter measuring method based on zero point analysis. The time difference type ultrasonic flowmeter measuring method based on zero point analysis is a method for accurately determining fair-current transmission time and countercurrent transmission time through a zero point analysis method. The time difference type ultrasonic flowmeter measuring method based on zero point analysis comprises the steps that (1) after a pulse drive signal is sent out, an A / D converter is started to conduct data collection; (2) a zero point value is searched; (3) whether a zero point is an ultrasonic signal zero crossing point or not is judged; (4) a first zero crossing point in an ultrasonic receiving signal is selected so that the ultrasonic signal arriving time can be determined and the fair-current transmission time and the countercurrent transmission time can be calculated; (5) instant flow of a section to be measured is calculated through the fair-current transmission time and the countercurrent transmission time. The zero point of the ultrasonic signal is not influenced by the external environment, the zero point can be detected even under the conditions that the signal is weak, fluctuation is large and interference is strong, the fair-current transmission time and the countercurrent transmission time of the ultrasonic signal in fluid can be accurately measured, the measuring accuracy of a time difference type ultrasonic flowmeter is greatly improved, and the problems brought by an existing threshold value comparing method are thoroughly solved.

The present invention provides a high-repetitive frequency pulse radar extension distance measurement range waveform design method. The present invention relates to a high-repetitive frequency pulse radar extension distance measurement range waveform design method. The objective of the invention is to solve the problem that the range ambiguity of the high-repetitive frequency pulse radar caused by pulse period repetition and avoid the problem that the duty ratio and the average power are decreased while increasing an unambiguous distance measurement range. The method comprises: 1, determining a corresponding relation of an inter-pulse phase modulation factor [Alpha] and the speed range and a target real speed and the number of times of distance folding; 2, performing inter-pulse phase modulation of linear frequency-modulation pulses, and obtaining intra-pulse linear frequency modulation inter-pulse phase modulation pulse signals; 3, performing radar emission of the intra-pulse linear frequency modulation inter-pulse phase modulation pulse signals, performing distance processing of the received target reflection echo, and obtaining target apparent distance; and 4, performing inter-pulse Doppler processing, and solving the range ambiguity to obtain a target real distance according to a speed result through adoption of inter-pulse Doppler processing. The present invention belongs to the radar signal design and processing field.

The invention discloses a high-precision multi-feature plane template. The high-precision multi-feature plane template includes a ChArUco black and white chequer template, wherein the chequer white area combination has an ArUco QR-code; the middle area of the ChArUco black and white chequer template is filled with random feature points to form a Random feature point template; and the edge area ofthe ChArUco black and white chequer template is provided with a plurality of segments with preset specific positions. The invention also provides a distortion optimization and calibration method of the high-precision multi-feature plane template. The high-precision multi-feature plane template and the distortion optimization and calibration method thereof have the advantages of solving the problemthat different focal length lens takes more images, consumes long operation time and is not accurate in edge distortion during the high precision calibration process; and conveniently and effectivelysolving the difficulty of calibration of a zoom lens by the calibration template, during the calibration process, having low requirement for the size of space, and not influencing the calibration function even when performing observation of part of the template; and the added linear segments around the calibration template, and being able to solve the problem of solving edge distortion without taking a large amount of images.

The invention relates to the field of medical jurisprudence inspection, in particular to a diatom inspection method in medical jurisprudence. The method at least comprises the following steps: (1) microwave digestion: adding concentrated nitric acid and hydrogen peroxide solution into the inspected sample to carry out microwave digestion; (2) vacuum filtration: carrying out vacuum filtration on the digestion solution, adding ultrapure water, carrying out vacuum filtration continually until the surface of the filter membrane is approximately neutral, adding absolute ethyl alcohol, and carrying out vacuum filtration to remove moisture from the filter membrane; (3) a scanning electron microscope automatically takes pictures and stores the pictures; and (4) qualitative and quantitative analysis on diatom: carrying out inspection, classification and statistic treatment on the diatom in the on-spot pictures in an artificial identification way or computer automated identification way. The invention has the advantages of high detection sensitivity, high accuracy of qualitative and quantitative analysis, simpleness, high efficiency and environmental protection, can effectively avoid pollution, greatly improves the working environment for diatom inspection technicians in medical jurisprudence, and reduces the labor intensity, thereby having wide application prospects in drowning diagnosis practice in medical jurisprudence.

The invention discloses a battery connector quality detecting method based on machine vision. A connector template data set is built; images of detected connectors are acquired; acquired original images of the battery connectors are cut to obtain images of rectangular window areas; the cut images are aslant corrected to obtain corrected images; the images are reconstructed until the images finishpretreatment; after the images are pretreated, positions of the connectors, connector FPC substrate copper exposure, connector central area defects, connector hardware part defects and connector plastic part detects are respectively detected by adopting independent detecting methods; detecting templates are updated in real time by adopting dynamic template update mechanisms; a coordinate system isbuilt based on the corrected images; the defects are classified, positioned and marked; detecting results are output; common quality problems of inclination / deflection, FPC plate copper exposure, hardware defects, plastic defects and central area defects of the connectors can be detected; and excellent instantaneity and higher detecting rate are achieved.

The invention discloses an optical interference type methane recognizer, relates to gases, in particular to a detecting instrument of methane concentration, and comprises a gas chamber, a light source, a convergent lens, a plane mirror that has a reflecting film on the back, a deviation prism, a reflecting prism and a telescope group. Two light beams that are respectively formed under the action of the plane mirror run through different gases, converge before entering the reflecting prism, enter the telescope group together, and generate specific light interference phenomena on a field lens focal plane of the telescopes, which is visible to the naked eyes and is utilized to form black stripes in the center and colored stripes at two sides, thus quickly obtaining the deviation percent of the methane content between a gas sample chamber and an air chamber, quickly and accurately measuring the methane concentration in air in coal mines and other work locations, and providing security insurance for underground working. The optical interference typed methane recognizer has convenient measurement and is favorable for underground operations at any time.

The automatic motor vehicle detecting system and its operation process belongs to the field of motor vehicle detecting technology. The automatic motor vehicle detecting system consists of one detection control center and detection sites. The detection control center including a log-on computer, a site data acquiring, controlling and processing computer, a printer and auxiliary equipment is installed in a service hall, accessed to LAN and operated in networked 'distributive acquisition and centralized processing' mode. The automatic motor vehicle detecting system may constitute different safety detection line or performance detection line as required. It completes data acquisition data transmission, equipment control, etc through network and remote control. The automatic motor vehicle detecting system possesses detection site control function, increased plate number recognizing function and B / S programming.

The invention discloses a measurement device for the swing angle of a multi-sling bridge crane. The multi-sling bridge crane comprises a bridge crane trolley provided with first lifting ropes. The measurement device for the swing angle of the multi-sling bridge crane is characterized in that the measurement device comprises a swing angle calculation and control computer, a fan-shaped plane infrared light emitter, a swing angle detection camera, lifting rope vertex markers and a video image processor; the fan-shaped plane infrared light emitter is used for emitting fan-shaped infrared light, and the light encounters one or more of the first lifting ropes, so that light spots are left; the swing angle detection camera is used for shooting images of the first lifting ropes; the video image processor is used for receiving the images of the first lifting ropes and finding the positions of the light spots and the lifting rope vertex markers; the swing angle calculation and control computer, the fan-shaped plane infrared light emitter and the video image processor are arranged on a second lifting rope, and the second lifting rope moves along with moving of the bridge crane trolley; and the swing angle calculation and control computer works out the position coordinates of the light spots and the lifting rope vertex markers, and thus a swing angle value is obtained. By adoption of the measurement device for the swing angle of the multi-sling bridge crane, the swing angle of the bridge crane can be detected accurately, and the measurement device has the advantages of being low in cost and high in antijamming capability.

The invention discloses a friction performance testing device for a slipper pair of a high-pressure axial plunger pump. The left and right sides of a box body are respectively provided with a high-pressure oil chamber and a sealed experiment chamber; the left and right ends of the box body are respectively provided with a left end cover and a right end cover of the box body; the high-pressure oil chamber is internally provided with a thrust piston; the end part of a piston rod of the thrust piston is arranged in the sealed experiment chamber and is connected with a slipper for testing through a connecting bolt; a swash plate stationary shaft is arranged on the right end cover of the box body; one end of the stationary swash plate shaft is arranged in the sealed experiment chamber, and a swash plate for testing is connected to the end through a bolt; and the other end of the swash plate stationary shaft is connected with a variable-frequency motor through a shaft coupling, and the variable-frequency motor is controlled by a frequency converter. By using the friction performance testing device, not only can the dry friction performance of the slipper pair of the high-pressure axial plunger pump be tested, but also different working states can be simulated to test. The friction performance testing device has the advantages of simple structure, convenience in use, accuracy in testing, low manufacturing and using costs and the like.

The invention relates to a new method for high-selectivity enrichment of serum glycopeptides group, and particularly relates to a method for high-selectivity enrichment of serum glycopeptides group by using a functionalization ordered mesoporous nanometer material, belonging to the field of biochemical analysis. The method comprises the following steps of: selecting the functionalization mesoporous nanometer material with an appropriate pore size so as to serve as a sample adsorbent, enriching endogenous glycosylation polypeptides in serum by using the double capacity of capture of glycopeptides combined with functional groups and size exclusion of mesoporous, and after sugar chains in PNGase F glycosidase are excised, carrying out nano-upgrading liquid chromatography-tandem mass spectrometry analysis, and searching and identifying amino acid sequences and corresponding glycosylation sites in a database, thus successfully realizing the revelation of serum glycopeptide epigenomics. The new method provided by the invention is simple in steps, convenient to operate, fast and efficient, can meet glycopeptide epigenomics research requirements and can be used for high-sensitivity detection and identification of the endogenous glycosylation polypeptides and further revelation of the serum glycopeptide epigenomics.

The invention provides a sample pretreatment method for hollow tubular polypyrrole naofiber-based azo dye detection. Various form reservation effects beween polypyrrole and azo dye modules are formed, and extraction selectivity of a target object is raised. In comparison with extraction efficiency by a commonly-used micron-sized solid-phase extraction medium, extraction efficiency is raised by a nanofiber nanostructure. By the hollow tubular polypyrrole nanofiber, specific surface area of the nanofiber is increased in comparison with specific surface area of solid core-shell nanofiber with a template, and absorption capacity is raised. Only by the use of several milligrams of polypyrrole nanofiber and several hectolambdas of an eluting solvent, high-selectivity high-efficiency extraction of various azo dyes in various practical samples can be realized, the sample matrix will not influence detection of a target object, and extraction efficiency is greatly raised in comparison with that of a commercially-produced solid phase extraction cartridge.

The invention relates to the technical field of radio frequency anti-counterfeiting identification and bottle caps and provides a radio frequency anti-counterfeiting identification system which is safer, more reliable and convenient to use and a bottle cap cooperating with the radio frequency anti-counterfeiting identification system. The radio frequency anti-counterfeiting identification system comprises an NFC anti-counterfeiting label, a card reader with a Bluetooth function and a smart phone, a tablet computer or a laptop computer. The bottle cap comprises an upper cap, a bottle mouth plug, a lower cover, a lining, an inner plug, the NFC anti-counterfeiting label and the like. The NFC anti-counterfeiting label comprising an NFC anti-counterfeiting chip 6c and a chip antenna 6d is placed between the position above the bottle mouth plug and the inner top surface of the outer upper cap. A corresponding automatic destroying-upon-opening structure is arranged on the bottle cap, when a product is identified and the bottle cap is opened, the structure destroys the NFC anti-counterfeiting label automatically, and the NFC anti-counterfeiting label cannot be recycled. The NFC anti-counterfeiting chip cannot be copied, is destroyed automatically once the bottle cap is opened and cannot be recycled, so that the anti-counterfeiting effect is excellent.

The invention relates to a liquid-based thin cell slide preparation device. The device comprises a rotary centrifugal mechanism and a plurality of liquid-loading slide preparation mechanisms arranged on the peripheral sides of the rotary centrifugal mechanism separately, wherein each liquid-loading slide preparation mechanism comprises a fixing base and filter pipes vertically inserted at the upper part of the fixing base, and rubber gaskets are arranged at the lower parts of the filter pipes. The invention aims to provide the liquid-based thin cell slide preparation device which is convenient to mount and dismount and good in slice preparation effect. The liquid-based thin cell slide preparation device has the advantages as follows: the liquid loading mechanisms are hinged with the rotary centrifugal mechanisms, so that cell sap in the filter pipes is perpendicularly thrown to slides, and the cell sap is uniformly spread; 2, a filter net is arranged at the lower part of each filter pipe and used for filtering the cell sap in the corresponding filtering pipe, so that cell sap entering the corresponding slide doesn't contain impurities; 3, compared with an L-shaped pipe, each straight tubular filtering pipe can contain more cell sap, and cells on each slide are more sufficient.

The invention discloses a blood additive, which is prepared from 6.0 to 8.8 g / 100ml of anticoagulants, 2.0 to 8.4 g / 100ml of nuclease inhibiting agents, 4 to 20 g / 100ml of cell stabilizing agents, 0 to 0.31 g / 100ml of purine, 2 to 10 g / 100ml of metabolic inhibitors, 0.021 to 0.21 g / 100ml of apoptosis inhibitors and 0.1 to 1 g of nucleic acid protection agents. Non-Cl<-> buffer solution is 90 to 110 mM, and the pH is 7.3 to 7.5. The blood additive can be used for storing blood at the normal temperature for 14 days without influence on detection.

The invention discloses a veterinary albendazole ivermectin premixing agent and a preparation method thereof. The veterinary albendazole ivermectin premixing agent disclosed by the invention comprises the following components in percentage by weight: 5.5-6.5 percent of albendazole, 0.22-0.26 percent of ivermectin, 5-15 percent of medicinal carbon, 5-10 percent of dextrose anhydrous, 30-59 percent of maize starch, 10-15 percent of an ivermectin pretreatment agent and the balance of an auxiliary material. The preparation method disclosed by the invention is simple in process, convenient to operate and easy to industrialize, and the product prepared by the preparation method disclosed by the invention is uniform in particle size, low in static electricity and good in uniformity.

The invention discloses a pressure-sensitive optical cable and a manufacture method thereof. The pressure-sensitive optical cable consists of two toothed plates made of a flexible material, and a polymer sheath tube sheathing the toothed plates, wherein the deformed teeth on the two toothed plates correspond to each other in a staggered manner; and a signal fiber is sandwiched by the deformed teeth of the two toothed plates. When a pressure is applied on the pressure-sensitive optical cable, the deformed teeth of the two toothed plates make relative movement so that the signal fiber generates bending deformation, thereby changing the bending loss of the signal fiber. Therefore, the pressure signal is converted into an optical signal, and is transmitted by the signal fiber to achieve the distal measurement. The toothed plate made of a flexible material has certain bending property, which can facilitate the manufacture, storage, transportation and use of the pressure-sensitive optical cable. Similar to the common optical cable, the pressure-sensitive optical cable has greatly reduced manufacture and use cost, and does not influence the pressure detection. The pressure-sensitive optical cable has the advantages of simple structure, reasonable design, convenience in manufacture, flexible use manner, high sensitivity and good use effect, and can achieve the distributed pressure measurement by use of measurement instruments, such as optical time-domain reflectometer.

The invention relates to an optical touch device, which comprises an infrared laser light source emission module, two infrared light detection modules and a system control module, wherein the infrared laser light source emission module is used for producing an infrared laser light source; the two infrared light detection modules are used for detecting infrared light which is irradiated to a touchobject by an infrared laser light source to be reflected respectively; and the system control module is used for receiving a detection result of the infrared light detection module to judge a coordinate position of the touch object.

The invention discloses a method for determining palladium by spectrophotometry. The method comprises the following steps that liquid to be tested and standard solution are prepared; the liquid to be tested and the standard solution measure the absorbancy A of test solution at a wavelength of 635nm; a standard curve is established according to the standard palladium solution with different concentrations and the corresponding absorbancy, and the slope k and the intercept b of the regression equation of the standard curve are calculated; and the amount of palladium m is calculated to be equal to kA plus b according to the equation. According to the palladium content testing method, the palladium can be directly determined without separating platinum, rhodium and other substances when the platinum, rhodium and other substances which do not affect the absorbancy at the wavelength of 635nm exist in a tested substance, and a process is simple and quick; the resistance to the interference of platinum, rhodium and the like is strong, the impact of an appropriate amount of platinum, rhodium and the like on a determination result is small, and the method is particularly applicable to the determination in a production process of a catalytic converter; the content of palladium is determined to be high and can reach 500mu.g; and compared with existing stannous chloride-acetone-potassium iodide spectrophotometry, the used amount of stannous chloride is only one tenth, so that the pollution is reduced, and the inspection cost is saved.

The invention belongs to the technical field of catecholamine detection pretreatment, and particularly relates to an LC-MS / MS detection method for catecholamine and a pretreatment kit. The content ofcatecholamine in blood is reduced, and catecholamine is very easily oxidized, the half-life period is only 12h under a 4DEG C dark condition, and the requirement of high-throughput detection is hardlymet. The invention provides the LC-MS / MS detection method for catecholamine and the pretreatment kit, by optimizing the extraction method and adding a stabilizer, the extraction effect and stabilization effect on catecholamines in a blood sample are improved, so that the catecholamines can be kept stable within 24h after the sample is pretreated, and the requirement of high-throughput detection is met.

The invention relates an array substrate and a manufacturing method thereof. The array substrate comprises an underlayer substrate; a plurality of data lines and grate scanning lines are transversely and longitudinally crossed on the underlayer substrate to encircle to form pixel units arrayed in a matrix form; TFT (Thin Film Transistor) switches and pixel electrodes are formed in the pixel units; the array substrate also comprise data join lines and grating join lines; and the data join lines are mutually isolated, are formed on the same layer with the data lines, the grating scanning lines or the pixel electrodes, and are connected with all the data lines via data through holes in a first insulation layer; and the grating join lines are mutually isolated, are formed on the same layer with the data lines, the grating scanning lines or the pixel electrodes, and are connected with all the grating scanning lines via grating through holes in a second insulation layer. In the invention, by adopting the technical scheme that the grating scanning lines and the grating join lines, as well as the data lines and the data join lines are arranged at intervals on the same layer or different layers, the signal to noise ratio and the defect relevance ratio of detection signals are improved when defects of the grating scanning lines and the data lines are detected.

The invention belongs to the field of quality control in microbial detection and particularly relates to a standard sample of staphylococcus aureus in milk powder and a preparationmethod of the standard sample of the staphylococcus aureus in the milk powder. The standard sample of the staphylococcus aureus in the milk powder comprises a target bacterium and background flora, wherein the target bacterium is the staphylococcus aureus; the background flora comprises Citrobacter freundii,E. coli, Klebsiella pneumonia and Bacillus cereus. The standard sample meets requirements for uniformity and stability, the stability of the standard sample can be guaranteed to the greatest extent, and a perfect preparation technology for the standard sample is formed by starting from meeting special transport conditions by means of research in special process, stability and uniformity and the like, is suitable for preparing the standard sample, meeting the requirements for uniformity and stability, of the staphylococcus aureus in the milk powder and is applicable to quality control, method validation and other purposes in a laboratory.

The invention provides a method for processing a cell sample in a single cell sorting process. The method comprises the following steps in sequence: 1, acquiring a required cell sample; 2, spreading the cell sample and a water retention substance for keeping cell activity on the surface of a sorting chip; 3, putting the chip on a sorting platform for sorting target cells; 4, putting the sorted cells into a receiving substance in a receiving device; and 5, performing subsequent detection or culture operation on the sorted cells. According to the method, the substance with a water retention function is used, so that the cells can keep the original biological state and biological activity in the sorting process, and detection and enlarged culture of the activity of the cells after sorting arenot influenced.

The invention provides a passive filtering device and method with lightning-protection isolation and fireproof early warning functions. The device has functions including ground potential back flashover isolation, fireproof early warning and passive filtering. Current detection of a fault arc is shared with current detection of passive filtering, the same detection signal is used, a common master control unit is used to analyze fault arcs and calculate content of harmonic waves at the same time, so that the device can sample the fault arc before characteristic current of the fault arc is detected and ensure accurate detection of the fault arc. The fault arc detection method uses a determination result of a current difference parameter as a premise, the change rate of the content of the harmonic waves is used to determine the fault arc, interference of nonlinear loads can be eliminated effectively, four determination means are used for determination, and the fault arc can be detected accurately under the condition of complex equipment.

The invention belongs to the technical field of materials, and relates to a polyvinyl alcohol-coated surface enhanced Raman scattering substrate and a preparation method thereof. The preparation method comprises the following steps of: (1) preparing a micro-nano gold / silver film on a surface; (2) performing annealing under a high-temperature condition to convert the gold / silver film into annealedgold / silver nanoparticles; and (3) dissolving polyvinyl alcohol to prepare a polyvinyl alcohol solution, and carrying out property coating modification on the annealed gold / silver nanoparticles by using the polyvinyl alcohol solution. The polyvinyl alcohol film provided by the invention can quench molecular fluorescence, can greatly improve the detection limit of a SERS substrate prepared by a physical annealing method, reduces direct contact between molecules and the gold / silver nano substrate, reduces detection substance residues, and ensures repeated utilization of the substrate; and the preparation method is simple in process and extremely low in cost.

The invention provides a sample pretreatment method for detecting basic orange II in a bean product based on a nylon 6 nanometer fiber membrane. The method comprises: 1) preparing a nylon 6 nanometer fiber membrane, wherein the nylon 6 nanometer fiber membrane is prepared by using an electrospinning solution through an electrostatic spinning method; and 2) extracting and purifying the basic orange II in a bean product sample, wherein the nylon 6 nanometer fiber membrane is made into a round sheet with a diameter of about 10-60 mm, the round sheet is arranged on a membrane disk type solid phase extraction instrument, the basic orange II is adsorbed on the nylon 6 nanometer fiber membrane, the obtained nylon 6 nanometer fiber membrane is leached with a washing agent so as to remove the impurity possible of being subjected to adsorption with the basic orange II molecules, and the basic orange II is eluted from the nylon 6 nanometer fiber membrane with an eluant so as to carry out analysis detection. According to the present invention, the high selectivity and high-efficiency enrichment and purification can be performed on the basic orange II dye in various actual bean product samples only with several milligrams of the nylon 6 nanometer fiber membrane and several hundred microliters of the eluant, wherein the sample matrix does not affect the detection on the target product, and the extraction efficiency is substantially improved compared with the commercially-produced solid-phase extraction small column.

The invention provides a static var generator with lightning protection isolation and fire prevention early warning and a method. The static var generator is a device with functions of ground potential counterattack isolation, fire prevention early warning, and SVG compensation, current detection of a fault arc and current detection of the static var generator are partly shared, the analysis of the fault arc and the calculation of the reactive current are simultaneously conducted through a common main control unit by employing the same detection signal, sampling can be performed by the device before the characteristic current of the fault arc is compensated, and accurate detection of the fault arc is guaranteed; and the detection method of the fault arc employs a determination result of a current difference parameter as the premise, the fault arc is determined by employing a harmonic content ratio change rate, the interference of a non-linear load can be effectively eliminated, determination is performed by simultaneously employing four determination methods, and the fault arc can be accurately detected.

The invention relates to an automobile front longitudinal beam detection table which comprises a detection tool vehicle, a workbench fixed to the detection tool vehicle and a detection assembly, the detection assembly is detachably fixed to the face, away from the detection tool vehicle, of the workbench, and the detection assembly comprises a simulation block used for installing an automobile front longitudinal beam, a plurality of supporting bases and a positioning module. The positioning module comprises a base and a limiting plate, one end of the limiting plate is rotationally connected tothe base, the other end of the limiting plate is detachably fixed to the base, and a fixing rod is arranged on the limiting plate. A plurality of mounting bases are fixedly connected below the simulation block, positioning pins are elastically arranged in the mounting bases in a sliding mode, one end of the head of each positioning pin is spherical, and the end, away from the head, of each positioning pin penetrates through the corresponding mounting base and the simulation block to be inserted into an assembling hole of the front longitudinal beam. According to the invention, the positioningpins are arranged below the assembly holes, and the matched positioning pins do not need to be found and inserted into the assembly holes when the front longitudinal beam is installed so that the time for installing the front longitudinal beam is saved, and the working efficiency of detection and measurement is improved.

The invention relates to an optical touch device, which comprises an infrared laser light source emission module, two infrared light detection modules and a system control module, wherein the infrared laser light source emission module is used for producing an infrared laser light source; the two infrared light detection modules are used for detecting infrared light which is irradiated to a touchobject by an infrared laser light source to be reflected respectively; and the system control module is used for receiving a detection result of the infrared light detection module to judge a coordinate position of the touch object.

The invention relates to a protecting method of exogenous DNA (deoxyribonucleic acid) internal standard substances in liquid products. The protecting method especially includes steps of mixing a polycation compound solution with a purposed DNA solution according to the proportion that phosphoramidic acid ratio is not less than 10: 1, and placing for 0.5-12 hours at the temperature of 2-20 DEG C after even mixing to obtain a stable DNA compound solution which can be directly added to the liquid products, wherein the phosphoramidic acid ratio is ratio of amino moles carried in polycation to moles of phosphate groups carried in DNA. With the method, tolerance of conditions of the exogenous DNA on nuclease, acid, free radical and the like can be improved by the aid of polycation compounds, and the polycation compounds can serve as traceable and anti-counterfeiting internal standard substances existing in the liquid products or merchandises with prolonged stability.

The invention relates to a biological adhesion-preventing device for an underwater membrane permeation sensor. The biological adhesion-preventing device comprises a watertight connector, a watertight lampshade, a UV ray lamp tube, a locking cover, a light-transmission piece, a copper net and a protected sensor, wherein the watertight lampshade is a bowl-shaped structure; a center of a bowl bottom and the watertight connector are subjected to screw thread pair fit; a small end surface of the bowl bottom is bonded to a sealing end surface of the watertight connector to form axial sealing fit; the locking cover and the watertight lampshade are subjected to the screw thread pair fit; the UV ray lamp tube is located at an internal space of the watertight lampshade; the protected sensor stretches into one side of the copper net; a large end surface of a bowel mouth of the watertight lampshade stretches into the other side of the copper net; the protected sensor, the copper net and the watertight lampshade are arranged coaxially; a pore size of a circular hole in the middle of the locking cover is slightly greater than a diameter of an external cylindrical surface of the light-transmission piece and is used for limiting radial displacement of the light-transmission piece. The biological adhesion-preventing device provided by the invention can be used for inhibiting biological adhesion of a membrane permeation sensor, and can prevent observed data from drifting and improve corresponding observation accuracy without affecting detection of such sensors.