119results about How to "Large linear range" patented technology

The invention discloses an automatic focusing microscope based on an eccentric beam method and a focusing method thereof. The hardware comprises an eccentric beam defocus amount detection module, a microscopic imaging module, a piezo lens drive, an XY stage and a computer processing system. The defocus amount detection module transmits a semicircular laser beam to irradiate the surface of a sample and acquire a semicircular spot image formed by sample reflection. The computer processing system uses self-adaptive median filtering, Canny edge detection based on OSTU, the least square fitting and other algorithms to process the grayscaled spot image to acquire spot radius. According to a radius-defocus amount linear relationship model, the sample defocus amount in a field of vision can be calculated. The piezo lens drive drives a lens to compensate the defocus amount. After focusing, the microscopic imaging module acquires a clear sample image. The automatic focusing microscope based on the eccentric beam method and the focusing method thereof, which are provided by the invention, have the advantages of fast focusing speed, high focusing accuracy and large linear range, and can meet the requirement of fast and precise focusing of the microscope under a high power lens.

The present invention concerns a new process for depositing a thick compact layer of biomolecules for instance such a layer with thickness in the μm scale and, for depositing a thick compact layer of cells in the μm scale. The deposited layer is made by application of an unbalanced (asymmetrical) alternating voltage polarization between two electrodes to a dissolved biomolecule or cell from low conductivity solutions. The process allows the rapid manufacturing of sensors and the coating of devices with functional cells and biomolecules. Examples are provided on the preparation of functional sensors such as a glucose, a lactose sensor, a hydrogen peroxide sensor and a glutamate sensor. Examples are also provided on the deposition of eukaryoric cells such as saccharomyces cerevisiae. The examples demonstrate a process that can be applied to coat devices with biomolecules and biological cells.

The invention discloses a liquid stable kit for measuring beta-hydroxybutyric acid by a cyclic enzyme method. The liquid stable kit consists of a reagent 1 and a reagent 2, wherein 1L of reagent 1 comprises 50 to 500mmol of buffer solution, 1 to 5KU of beta-hydroxybutyrate dehydrogenase, 1 to 5KU of diaphorase, 0.1 to 100g of surfactant, 1 to 100mmol of stabilizer, 0.1 to 100g of anti-interference agent I, 0.1 to 100g of anti-interference agent II, and 0.1 to 100ml of preservative; and 1L of reagent 2 comprises 50 to 500mmol of buffer solution, 1 to 20mmol of coenzyme I, 0.1 to 10mmol of nitrotetrazolium blue, 1 to 100mmol of stabilizer and 0.1 to 100ml of preservative. The liquid stable kit has the advantages of stability, wide linear range, high measurement accuracy, high antijamming capability and low cost.

The invention discloses a method for measuring micro impulse by Doppler galvanometer sine-modulated multi-beam laser heterodyne second harmonic, relates to a method for measuring micro impulse and aims to solve the problems of low acquired laser difference frequency signal quality and low signal processing computing speed in the micro impulse measurement of conventional laser heterodyne methods. The method comprises the following steps of: exciting a working medium target to generate plasma jet to rotate a beam of a standard beam; starting a driving power supply of an H0 solid laser and a galvanometer, and causing the galvanometer to perform simple harmonic motion and modulate optical frequency incident to the front surface of the galvanometer at different moments under the action of the driving power supply; and continuously acquiring signals transmitted by an optoelectronic detector in the pendulum process of a torsional pendulum system, and processing all the continuously acquired signals to obtain the micro impulse to which the beam of the standard beam is subjected by using a signal processing system. The method has the prominent advantages of high acquired laser difference frequency signal quality and high signal processing computing speed.

The invention provides a cystatin C detection kit and a preparation method thereof. The kit comprises a reagent R1, a reagent R2 and a cystatin C calibration product, wherein the reagent R1 comprisesa preservative, a surfactant, an emulsifier and a buffer solution; the reagent R2 comprises a cystatin C antibody, polystyrene latex microspheres, a latex microsphere activating agent, a sealing agent, an emulsifier, a preservative, a surfactant and a buffer solution. The cystatin C antibody is slowly dropwise added to an activated polystyrene latex microsphere solution, a polystyrene latex microsphere suspension coupled with the cystatin C antibody is obtained after a stirring reaction, sealing is performed, the antibody and latex microspheres are coupled together in a chemical crosslinking manner, and centrifugation, cleaning and ultrasonic resuspension processes in conventional methods are omitted. The production process is simplified, and the kit has the advantages of low blank absorbency, high sensitivity and precision and large linear range.

The invention discloses a full-automatic collecting liquid-plastic limit combined measuring system. The full-automatic collecting liquid-plastic limit combined measuring system comprises a liquid-plastic limit combined measuring instrument and a computer, wherein the liquid-plastic limit combined measuring instrument comprises a mounting frame, a cone head, an electromagnet, a displacement transducer, a displacement display screen, a CPU (central processing unit), a communication module, a control switch and a specimen cup; the specimen cup is placed on the mounting frame; the electromagnet, the displacement transducer, the displacement display screen, the CPU, the communication module and the control switch are arranged on the mounting frame; the cone head is arranged above the opening of the specimen cup and is adsorbed on the electromagnet; the displacement transducer is connected with the computer in a signal manner through the CPU and the communication module; and a double logarithmic chart is stored in the computer. The full-automatic collecting liquid-plastic limit combined measuring system provided by the invention can be used for acquiring, measuring and reading data in a full automatic manner and drawing a curve, so that the accuracy of the test data is improved, the work amount of experimenters is reduced, the cost of human resources is reduced, and the test efficiency is improved.

The invention discloses a method for detecting a potassium ion by preparing a biosensor based on a G-quadruplex and a gold nanoparticle, and belongs to the field of the biosensor. A detection method comprises the following steps of: modifying the gold nanoparticle on the surface of a gold electrode by taking para-aminothiophenol (p-ATP) as a medium, fixing a DNA (Deoxyribose Nucleic Acid) marked by ferrocene (Fc) and capable of forming a G-quadruplex structure onto the surface of the gold nanoparticle by a sulfydryl self-assembly action, and taking the DNA as an aptamer to prepare an electrochemistry biosensor to detect the potassium ion. The method for detecting the potassium ion by preparing the biosensor based on the G-quadruplex and the gold nanoparticle has the advantages that the detection is simple and quick, the sensitivity is high, the real-time detection can be carried out on the potassium ion, the minimum detection concentration to the potassium ion reaches 0.1 mM, and the linear range of the detection is large. In a concentration range of 0.1-1 mM, a square wave volt-ampere peak current is in a well linear relation with the concentration of the potassium ion; and in a concentration range of 1-30 mM, the square wave volt-ampere peak current is in a well linear relation with the logarithm of the concentration of the potassium ion.

The invention discloses a non-contact anchor rod drawing force measuring method based on an eddy current impedance method, and belongs to the technical field of modern measurement and control. The non-contact anchor rod drawing force measuring method comprises the steps of arranging an eddy current sensor on the surface of a nut in an anchor rod assembly, analyzing and obtaining a relationship between an impedance value of the eddy current sensor and a drawing force of an anchor rod through an impedance measuring and analyzing device, and thus indirectly reflecting the drawing force level of the anchor rod by adopting the change of a sensor impedance value which is actually measured and obtained. The non-contact anchor rod drawing force measuring method disclosed by the invention is simple and easy to implement, has a very good application value and can be used for measuring the drawing force of the anchor rod which is commonly used in roadway support.

The invention relates to a method for measuring a micro impulse, more particularly to for a second harmonic multi-beam laser heterodyne measurement method for a micro impulse based on doppler oscillating mirror sinusoidal modulation. The invention aims at solving a problem of poor qualities of collected laser difference frequency signals and slow operation speeds of signal processing during microimpulse measurement in the current laser heterodyne method. According to the method, a pulsed laser emits a pulse laser excitation working medium target that generates plasma injection, and the plasma injection enables a crossbeam of a standard beam to make rotations; driving powers of an H0 solid state laser and an oscillating mirror are started; the oscillating mirror, which is driven by the driving power, makes simple harmonic motions and carries out modulation on optical frequencies that are incident to the front surface of the oscillating mirror at different times; and a signal processing system collects continuously signals emitted by a photoelectric detector during a swing process of a torsion pendulum system and also carries out processing on all continuously obtained signals, so that a micro impulse I exerted on the crossbeam of the standard beam is obtained. According to the invention, the method has advantages of high qualities of collected laser difference frequency signals and a fast operation speed during signal processing.

The invention discloses a method for detecting thrombin through a biosensor prepared based on an ionic channel and an aptamer, belonging to the field of biosensors. The method comprises the steps of: modifying a DNA (Deoxyribonucleic Acid) aptamer on an ionic channel, processing by using a P-ATP () mixture solution, and finally performing metal spraying to obtain a product serving as a work electrode, thereby obtaining the biosensor based on the ionic channel and the aptamer for detecting the thrombin. The biosensor disclosed by the invention has the advantages of simplicity, rapidness, high sensitivity and good selectivity, can be used to perform detection on actual samples, and has the minimal detection concentration reaching 1pM for the thrombin and a larger linear range. Within the concentration range from 3nM to 50nM, a linear relation exists between detected square wave volt-ampere peak current and the logarithm of concentration; the peak current value is stable, and the difference between the peak current value at the 10th circle and the peak current value at the 100th circle is within 3%; and the biosensor has very strong specificity, repeatability and practicability and has the recovery rate being 92-105% for the actual samples.

The invention discloses an abrasive particle monitoring sensor of oil. The sensor mainly comprises an excitation source, a detection conversion module, a signal conditioning module and a signal acquisition module, wherein the detection conversion module comprises two identical PCB (printed circuit board) planar coils, two identical capacitors and two identical resistors. The signal conditioning module comprises two identical conditioning branches and a differential amplification circuit; input ends of the two conditioning branches form two input ends of the signal conditioning module and are connected with an output end of the detection conversion module; output ends of the two conditioning branches are connected with two input ends of the differential amplification circuit; and an outputend of the differential amplification circuit forms an output end of the signal conditioning module and is connected with an input end of the signal acquisition module. The current vortex based PCB planar coil sensor has the characteristics of simple structure, high sensitivity, a wide linear range, high interference resistance, non-contact measurement, low cost and the like.

A pulsed discharge helium ionization detector for gas chromatography with multiple combined bias / collecting electrodes.

The invention provides a method for determining alcohol concentration by using an enzyme cycling method and an alcohol determination kit. The method comprises the following steps of: generating reduced nicotinamide adenine dinucleotide I by using nicotinamide adenine dinucleotide I and alcohol under the action of alcohol dehydrogenase, reacting the reduced nicotinamide adenine dinucleotide I with oxidized iodonitrotetrazolium (INT) under the action of diaphorase to generate red reduced INT, detecting a change in the absorbance of a final reactant, and then calculating the alcohol concentration of a sample. The kit consists of the following components: 0.05 to 0.5M of a buffer solution, 0.1 to 10g / L of a stabilizer, 0.05 to 10g / L of nicotinamide adenine dinucleotide I, 0.5 to 50KU / L of alcohol dehydrogenase, 0.05 to 50KU / L of diaphorase, 0.1 to 10g / L of oxidized INT and 0.1 to 10g / L of a preservative. The method is high in reaction specificity, detection specificity and sensitivity, wide in linear range and low in cost; and the kit is high in stability and accuracy.

A novel Si MEMS piezoresistive resonator is described. The resonator has a shape of a frame, such as a ring or a polygon frame, which has two or more anchors. Electrodes located at the outer or inner rim of the resonant structure are used to excite the structure electrostatically into resonance with a desired mode shape. One or plurality of locally doped regions on the structure is used for piezoresistive readout of the signal. In the most preferred embodiments, the structure is a ring, which has four anchors, two electrodes and four piezoresistive regions at different segments of the structure. The piezoresistive regions are alternatively located at the outer rim and inner rim of the structure in such a way that the piezoresistive signals of the same sign from different regions can be collected. Advantages of this device are large readout signal, large electrode area, robustness, suppressed out-of-plane vibration and larger usable linear range.

The invention provides a device for measuring torsional pendulum micro impulse through linear frequency modulation multi-beam laser heterodyning and a torsional pendulum micro impulse measuring method based on the device, and belongs to the field of torsional pendulum micro impulse measurement. The device and method are used for solving the problem that an existing torsional pendulum micro impulse measurement method and device are low in measurement precision. Laser emitted by a pulse laser acts on a working medium target to generate plasma jet, the back jet effect enables a standard beam to rotate, while the standard beam rotates, a linear frequency modulation laser continuously emits linear frequency modulation laser light which is reflected to a plane standard mirror through a first plane mirror and a second plane mirror, the front surface and the rear surface of the plane standard mirror both reflect the linear frequency modulation laser light, the linear frequency modulation laser light is gathered on the photosensitive face of a photoelectric detector through a convergent lens, the photoelectric detector sends electric signals to a signal processing system to obtain a tilt angle theta' of the standard beam, and according to a formula, micro impulse I' generated by the effect of the laser emitted by the pulse laser and the working medium target is obtained. The device and method are suitable for measuring the torsional pendulum micro impulse.

The invention relates to a device for adopting a linear frequency modulation double beam laser heterodyne method and a torsional pendulum method to measure micro impulse and a measuring method thereof and belongs to the field of micro impulse measurement. The problem that existing devices and methods for micro impulse measurement are low in measurement precision is solved. The linear frequency modulation double beam laser heterodyne method is applied to the micro impulse measurement method, measurement of the micro impulse is converted into measurement of a standard beam torsional pendulum angle, information of the to-be-measured standard beam torsional pendulum angle can be obtained indirectly through the measurement of the thickness of a plane standard lens, measurement accuracy is effectively improved, the measured micro impulse and the incidence angle theta 0 form linear relations when the turning angle is small (smaller than 5 degrees), the measuring error is smaller than 0.52%, the requirements of impulse measurement of a laser micro thruster can be met, and a good measurement means is provided for evaluating the performance of the laser micro thruster. The device and the measuring method are mainly applied to evaluation of the laser micro thruster.

The invention provides a device for measuring a micro-impulse by adopting a linear frequency modulation double-beam laser heterodyne method and a torsion method, and a measuring method of the device and belongs to the field of micro-impulse measurement. The problem that an existing device and method for measuring the micro-impulse are low in measurement precision is solved. The linear frequency modulation double-beam laser heterodyne method is applied to the micro-impulse measuring method, measurement of the micro-impulse is converted into measurement of the torsion angle of a standard beam, information of the torsion angle of the standard beam to be measured can be obtained indirectly by measuring the incident light refraction angle of a plane standard mirror, and the measurement precision is effectively improved; when the rotating angle is smaller than five degrees, the linear relation between the measured micro-impulse and the incidence angle theta 0 is formed, a measurement error is smaller than 0.52%, the requirement for impulse measurement from a laser micro-thruster can be met, and a good measuring means can be provided for evaluating the performance of the laser micro-thruster. The device is mainly applied to evaluation of the laser micro-thruster.

The invention relates to a copper-cobalt bimetal organic framework nano-enzyme and a colorimetric analysis method of an organic phosphorus colorimetric sensor thereof, which comprises the following steps: firstly, synthesizing the copper-cobalt bimetal organic framework nano-enzyme (CuCo-ZIF) by taking CTAB (Cetyltrimethyl Ammonium Bromide) as a soft template, 2-methylimidazole as an organic ligand, copper nitrate trihydrate as a copper source, cobalt nitrate hexahydrate as a cobalt source and deionized water as a solvent; the CuCo-ZIF nano-enzyme synthesized by the method has a regular cubic structure, so that the CuCo-ZIF nano-enzyme has a relatively large specific surface area, high porosity and high stability, and the peroxidase activity of the nano-enzyme is greatly improved. The method comprises the following steps: firstly, preparing a nano-enzyme, then constructing a colorimetric sensor by using the nano-enzyme, performing colorimetric analysis to directly and visually detect organophosphorus, can quickly, simply and visually realize high-sensitivity detection of organophosphorus, and has the advantages of good stability, low detection limit, high sensitivity, good specificity and the like.

The invention provides a device and method for measuring micro impulse by means of a linear frequency modulation multi-beam laser heterodyne quadratic harmonic method and a torsional pendulum method, and belongs to the field of optics. The device and method are aimed to solve the problems that according to an existing laser interference method for measuring the micro impulse, accidental errors are large and measurement precision is low. Linearly polarized light emitted from a linear frequency modulation laser device is reflected through a first plane reflection mirror and a second plane reflection mirror and then enters a plane standard lens, light beams penetrating through the front surface of the plane standard lens are reflected by the rear surface and the front surface of the plane standard lens in the plane standard mirror for many times, then multiple beams of reflection light are obtained, the beams of reflection light penetrate through the front surface of the plane standard lens, then the beams of the reflection light and the light beams reflected through the front surface of the plane standard lens penetrate through a vacuum window and are converged to a photosensitive face of a photoelectric detector outside a vacuum chamber through a convergence lens, the photoelectric detector outputs electric signals to a signal processing system, and the signal processing system obtains the micro impulse borne by a standard beam according to the electric signals received continuously. The device and method are suitable for measuring the micro impulse.

An embodiment of the invention discloses a solution concentration detection method, device and equipment and a storage medium. The method includes the steps: determining the most approximate standardconcentration in two adjacent set time periods according to calibration curves of at least two types of standard solution in the set time periods; acquiring the sample concentration of solution to bedetected in the set time periods according to the absorbance of the solution to be detected in the set time periods and the calibration curves in the set time periods; determining the calibrated sample concentration in a current time period according to the sample concentration in the current time period, the most approximate standard concentration in the current time period and a next time period, the difference value of the most approximate standard concentration, the sample concentration in the next time period, the most approximate standard concentration in the current time period and thenext time period and the difference value of the most approximate standard concentration; taking the same calibrated sample concentration as the concentration of the solution to be detected if the calibrated sample concentration in two or more continuous set time periods is the same. Testing stability and accuracy are improved.

The invention relates to a concentration analysis method. The method comprises the following steps: pretreating a sample to be measured; converting an element to be measured into a gaseous compound; introducing the gaseous compound of the element to be measured into a multi-reflection spectral absorption cavity through carrier gas; detecting the attenuation of the laser power in the cavity to obtain a gas laser absorption spectral line; calculating the concentration of a gaseous compound of the element to be measured. In the method, a molecular absorption spectral line is directly adopted for analyzing without using consumable instruments such as a chromatographic column or accessories such as an atomization furnace or an ionization furnace or being interfered with background absorption and fluorescence. In the method, the absolute absorption of light is analyzed by using the sample without frequently making a standard measuring curve as being done for an atomic spectra and the like, so that the measuring flow can be simplified, and the scalar period can be prolonged on a large scale to realize instant measurement, so that the automation and the convenience in measurement are realized. The method has the advantages of high analysis speed, low equipment cost, high sensitivity and accurate measurement.

The invention relates to a competitive hog cholera virus antibody chemiluminescence quantitative detection kit, which comprises a coating antigen coated plate, an enzyme-labeled antibody, a calibrator, a washing concentrate, a luminescent substrate A and a luminescent substrate B, wherein a purified hog cholera virus E2 protein is taken as a coating antigen of the antigen coated plate; the enzyme-labeled antibody is a hog cholera virus monoclonal antibody labeled by horseradish peroxidase; hyperimmune serum immune to a live vaccine is diluted to concentrations of 0NU / mL, 2NU / mL, 5NU / mL, 10NU / mL, 30NU / mL and 60NU / mL by a calibrator diluent respectively; the luminescent substrate A contains luminol, hydroxycoumarin, gallic acid and a Tris-Hcl buffer solution. The kit has the advantages of short detection time, capability of greatly enhancing a detection signal, high sensitivity and the like.

The invention provides a device for measuring torsional pendulum micro impulse through linear frequency modulation multi-beam laser heterodyne and a torsional pendulum micro impulse measurement method based on the device and relates to the technical field of torsional pendulum micro impulse measurement. By the adoption of the device for measuring torsional pendulum micro impulse through linear frequency modulation multi-beam laser heterodyne and the torsional pendulum micro impulse measurement method based on the device, the problem that by the adoption of an existing device and method for measuring torsional pendulum micro impulse, the measurement precision is low is solved. According to the device for measuring torsional pendulum micro impulse through linear frequency modulation multi-beam laser heterodyne and the torsional pendulum micro impulse measurement method based on the device, a laser emitted by a pulse laser device acts on a working medium target, so that plasma spray is generated, a standard beam rotates under the action of back spray, when the standard beam rotates, a linear frequency modulation laser device continuously emits linear frequency modulation lasers, the linear frequency modulation lasers are reflected by a first plane mirror and a second plane mirror and irradiate a plane standard mirror in an incidence mode, the front surface and the rear surface of the plane standard mirror both reflect the linear frequency modulation lasers, the linear frequency modulation lasers are focused on a photosensitive surface of a photoelectric detector through a convergent lens, the photoelectric detector sends electric signals to a signal processing system, so that the tilt angle theta' of the standard beam is obtained, and then the micro impulse I' generated by action between the lasers emitted by the pulse laser device and the working medium target is obtained according to a formula. The device for measuring torsional pendulum micro impulse through linear frequency modulation multi-beam laser heterodyne and the torsional pendulum micro impulse measurement method based on the device are suitable for torsional pendulum micro impulse measurement.

The invention discloses an immunodetection method of 25-hydroxyvitamin D. The immunodetection method comprises the following steps of pairing a No.3 antibody of anti-25-hydroxyvitamin D and a No.22 antibody of anti-25-hydroxyvitamin D, and respectively capturing and detecting a conjugate of 25-hydroxyvitamin D-macromolecular protein to form a double-antibody sandwich compound; the application comprises a lateral chromatography platform, an enzyme-linked immunosorbent assay (ELISA) platform, a chemiluminescence platform, a microfluidic platform and an immunoturbidimetric platform. The invention discloses an immunodetection method of 25-hydroxyvitamin D and an application thereof and relates to the field of immunodetection methods. The immunodetection method is advantaged in that project development difficulty is reduced, development cost is saved, development efficiency is improved, and the immunodetection method can be combined with 25-hydroxyvitamin D in a sample, so reagent performance is improved, the amount of effective competitive antibodies is much larger than that of conventional methods, so both sensitivity and reactivity can be considered, and the linear range can also be increased.

The invention relates to a voltage-controlled oscillator circuit comprising a resonant cavity module and a power supply module, wherein the resonant cavity module increases the tuning range of the voltage-controlled oscillator circuit and the linearity of the gain of the voltage-controlled oscillator circuit by adopting three groups of coupled inductor structures, the phase noise is reduced, no capacitor array needs to be used, and the influence of stray capacitance on the oscillation frequency is reduced. The invention further relates to a phase-locked loop, the phase-locked loop comprises avoltage-controlled oscillator circuit and a frequency divider portion, and the frequency divider portion is a combination of a high-speed frequency-halving circuit and a prescaler, thereby not only ensuring the accuracy of the frequency dividing ratio, but also reducing the power consumption required for the frequency divider portion, and simplifying the circuit structure.

The invention discloses a primer, a probe and a method for identifying dalbergia latifolia among rosewood. The method is implemented by the aid of the primer and the probe which have special specificity for the dalbergia latifolia and is based on polymorphism information of sequence sites of genes of the dalbergia latifolia, so that dalbergia latifolia species identification results can be accurately and objectively acquired, and the shortcoming that the traditional identification methods need to be depended on complete and easily identifiable morphological structures of wood can be overcome. The primer, the probe and the method have the advantages that accurate wood information can be provided in law enforcement procedures, and the primer, the probe and the method have important significance on standardizing markets, protecting rights and interests of consumers and promoting protection and utilization of species resources; only extremely few samples are required, and accordingly destroy on appearance structures of wood can be prevented in identification procedures.

The invention discloses a dynamic drift demodulation device and method for a fiber grating and belongs to the technical field of fiber grating sensing. By virtue of the linear relationship between the reflected light power of a fiber semiconductor coated device and the wavelength change of incident light, the leftward / rightward offsets of the central wavelength of the fiber grating which is subjected to external modulations are demodulated, to generate light power signals which are convenient to measure, thus achieving the dynamical drift demodulation of the fiber grating.

The invention relates to a method of constructing an electrochemical aptamer sensor with a TiO2 nanorod composite as an electrochemical tracer agent. The method comprises steps of: depositing Pt-Sn dual-metal nanoparticles on the surface of a cylindrical TiO2 nanorod uniformly through an alcohol reduction method and synthesizing a PtSn@TiO2 nano composite; dispersing the PtSn@TiO2 nano composite in a chitosan solution and then dripping the solution onto the surface of a GCE electrode, fixing NH2-cDNA on the surface of the modified electrode with BS<3> as a diamino crosslinker, and then fixingstreptomycin aptamer on the electrode through DNA hybridization of NH2-cDNA and the aptamer. When a mixture of streptomycin and exonuclease is introduced, the aptamer can combine with streptomycin specificity preferentially and separate from NH2-cDNA on the surface of the electrode so as to form a single-chain DNA structure. Exonuclease acting on the single-chain DNA alone digests and degrades single-chain NH2-cDNA, aptamer-streptomycin compound selectively, so as to enable the compound to release streptomycin, and released streptomycin can combine with remaining aptamer specificity on the surface of the electrode circularly. The electrochemical aptamer sensor can detect streptomycin rapidly and sensitively, and has a large linear range and low detection limit.

The invention discloses a capacitive pressure sensor and a manufacturing method thereof. The problem that an existing pressure sensor is small in linear range is mainly solved. The sensor comprises amonocrystalline silicon substrate (1), an insulating layer (2), an isolating layer (3) and a polycrystalline silicon film (4) from bottom to top. The insulating layer (2) is composed of N stacked circular steps, wherein the radius of each stacked circular step is gradually reduced from top to bottom. Wherein N is not less than 2, and the thicknesses of the circular steps are the same; the polycrystalline silicon film (4) has different radii, a through hole (5) for corroding the isolation layer (3) is etched on the polycrystalline silicon film (4), the isolation layer (3) forms a cavity (6) through corrosion, metal electrodes (8) are deposited on the polycrystalline silicon film (4) and the monocrystalline silicon substrate (1), and passivation layers (7) cover other surfaces of the isolation layer, the through hole and the polycrystalline silicon film except the metal electrodes. The invention has the advantages of large linear range, simple process and high yield, and can be used formeasuring large-range pressure in the fields of automobile systems and industry.

A pulsed discharge helium ionization detector for gas chromatography with multiple combined bias / collecting electrodes.