51results about How to "Suitable for standardization" patented technology

The invention discloses a reconstruction method for producing the Vitamin C precursor 2-KLG with gluconobacter oxydans, and belongs to the field of genetic engineering. According to the invention, a sorbose dehydrogenase (SDH) gene and a sorbosone dehydrogenase (SNDH) gene originated from ketogulonigenium vulgare are expressed in gluconobacter oxydans to obtain a G. oxydans engineering bacteria for production of 2-KLG by using sorbitol. G. oxydans is a frequently used strain in the first step of fermentation in the method of two-step fermentation; in the invention, the SDH and SNDH genes are expressed in G. oxydans, which enables the problem of dependency of ketogulonigenium vulgare on associated fungi to be overcome, direct conversion of D-sorbitol into 2-KLG to be realized and the production process for Vitamin C to be simplified; output of 2-KLG reaches 83 g / L; therefore, the invention has a very good application prospect.

The invention discloses a manufacturing method of ramie paper. The method has the advantages that the ramie (bast) is used as the raw material, and the paper is manufactured by the traditional manual methods of ramie sun and rain bleaching, microorganism fermentation and degumming, processing of natural paper medicines, dying of plant pigments, and the like, so the damage to the plant fiber is avoided, the quality of paper products is furthest improved, and the wastes generated in the whole technological process can be completely degraded, thereby realizing the non-toxic, non-harmful and pollution-free effects and meeting the national environment-protection standards; the manufactured ramie paper has the characteristics of classic elegance, high flexibility, softness and attractive appearance, is suitable for the restoration of ancient rare books and the creation of calligraphy and drawing, and can reach the better effect of non-decay for thousands of years; the technical standard is normative, so the method is suitable for factory production, and the good economic benefits and social benefits are realized.

The invention discloses a yeast engineering bacterium for producing d-limonene and a construction method thereof, belonging to the field of gene engineering. In the invention, limonene synthetase from Citrusunshiu is heterologously expressed in Saccharomyces cerevisiae CEN.PK2-1C by metabolic engineering modification to increase ways (mevalonic acid (MVA) carbon metabolic flux) for synthesizing terpenoids, thereby obtaining a yeast engineering bacterium strain CEN.PK2 limonene for producing d-limonene at high yield. Compared with the original strain CEN.PK2-1C, the modified yeast engineering bacterium can produce d-limonene by metabolism, the feedback inhibition on d-limonene is obviously lowered, and the yield of d-limonene can reach 13 mg / L, thus the invention has wide application prospects.

The invention discloses a method for measuring dimethyl fumarate in a product by gas chromatography-mass spectrometry. The method comprises the following steps of: pretreating a dimethyl fumarate product to be detected by using an ultrasonic extraction method; setting the temperature of a sample injection port of a gas chromatography-mass spectrometer to be 240-280 DEG C, a flow rate to be 0.8-1.5 ml / min and the temperature of a port to be 280-300 DEG C, and selecting a weak polar column for a chromatographic column; enabling a sample to enter the chromatographic column through the sample injection port, and carrying out temperature programming on the temperature of the chromatographic column to separate the components of the sample by the chromatographic column; and enabling the components separated by the chromatographic column to enter a mass spectrometric detection part through the port of the gas chromatography-mass spectrometer, wherein an electron impact ion source is adopted as the ion source of the mass spectrometric detection. The method for measuring the dimethyl fumarate in the product by the gas chromatography-mass spectrometry has low detection limit, good detection effect, little consumption of analysis solvent and low detection cost.

The invention discloses a high-yield s-linalool genetic engineering strain and a building method, which belong to the field of genetic engineering. Through the metabolic engineering reformation, linalool synthetase from actinidiaarguta is expressed in saccharomyces cerevisiae CEN.PK2-1 in a heterologous way, the terpene synthesis path-mevalonic acid (MVA) path carbon metabolizing flow is increased, and the high-yield s-linalool genetic engineering strain CEN. PK2 linalool is obtained. Compared with an initial strain CEN. PK2-1C, the modified genetic engineering strain CEN. PK2 linalool can metabolize and produce s-linalool, in addition, the feedback inhibition of the s-linalool is obviously reduced, the yield of the s-linalool can reach 12 mg / L, and the genetic engineering strain has good application prospects.

The invention provides a method for detecting polycyclic aromatic hydrocarbon in food contact material by gas chromatogram-mass spectrometry coupling technique, comprising: Soxhlet extraction method or ultrasonic extraction method is used for extracting the detected food contact material; the extract sample is detected by a gas chromatogram-mass spectrometry coupling instrument; the temperature of a sample inlet of the instrument is set to be 240-320 DEG C, and the flow rate of carrier gas is set to be 0.5-2.0ml / min; a weakly polar chromatographic column is adopted, and the interface temperature is set to be 180-300 DEG C; the pretreated sample enters into the chromatographic column through the sample inlet of the instrument for temperature programming, and the temperature is raised to be 270-330 DEG C from 70-100 DEG C; after being separated by the chromatographic column, all the components in the sample are detected by mass spectrum. The method has the characteristics of low price of the detection instrument, safety, accurate and rapid analysis method and little interference as well as being suitable for standard analysis and detection which can lead all the components of the polycyclic aromatic hydrocarbon in the sample to be cracked in a mass spectrum ion source and optimize all the components of the cracked product, etc.

The invention discloses a Gluconobacter oxydans engineering bacterium for producing vitamin C synthesis intermediate sorbic ketone and a construction method and application thereof, and belongs to the field of genetic engineering. By means of the genetic engineering technique, a sorbose dehydrogenase gene (sdh) derived from common ketogenic base Ketogulonigenium vulgare is cloned onto Gluconobacter oxydans to obtain the G. oxydans engineering bacterium for producing the sorbic ketone by utilizing sorbitol. G. oxydans WSH-003 which is provided by Jiangsu Jiangshan Pharmaceutical Co., Ltd is a fermented industrial strain obtained in a first step of a two-step fermentation method for producing 2-keto-L-gulonic acid (2-KLG). The sdh is cloned into the G. oxydans so that conversion from D-sorbitol to the vitamin C synthesis intermediate sorbic ketone is achieved, the foundation for further constructing the fermented industrial strain in one step to produce the direct precursor 2-KLG of vitamin C is laid, and the yield of the sorbic ketone is as high as 72g / L. Therefore, the Gluconobacter oxydans engineering bacterium has good application prospects.

The invention belongs to the technical field of purification enrichment pre-treatment for food packaging material pollutant biphenol substance. The purification enrichment pre-treatment technology comprises the following steps of: activating a C18 inverse solid phase extraction small column by methanol and ultra pure water and then loading, firstly leaching with 20% of methanol aqueous solution, then eluting with methanol, drying eluate with nitrogen in a blowing manner, redissolving residue with acetonitrile, filtering, and then carrying out liquid chromatography-fluorescence detection. By adopting the pre-treatment technology provided by the invention, recovery ratio of six biphenol substances (biphenol A (BPA), biphenol B (BPB), biphenol E (BPE), biphenol F (BPF), biphenyl A diglycidyl ether (BADGE) and biphenol F diglycidyl ether (BFDGE)) is 75.92-102.10%, relative deviation is respectivel lower than 5%, and accuracy and precision are high.

The invention discloses a Davallia mariesii breeding method, which comprises the following steps: an induction proliferation medium and a rooting medium are provided, the inducting and proliferation cultivating are concurrently carried out, after exercising seedling, and the seedling can be directly transplanted to a seedlings bag for culturing. The invention provides a technical scheme of a key link in a seedling breeding technology process of the Davallia mariesii, the proliferation rate is fast, the reproduction rates can reach 5-7 times during one period with 25-30 days; the rooting culture lasts about 20 days, each plant can breed 5-8 roots, the seedling is robust, the root develops, a tissue culture process is simplified, the cost and production time are greatly reduced, and the Davallia mariesii breeding method is suitable for standardization and industrial-scale production.

The invention discloses a method for improving gluconobacter oxydans for producing 2-keto-L-gulconic acid, and belongs to the technical field of genetic engineering. On the basis of genetic engineering transformation, adaptor protein SH3 and ligand protein SH3lig of the adaptor protein, a CutA gene and a key enzyme gene in saccharic acid transformation are subjected to fusion expression, and G.oxydans is transformed to produce 2-KLG in a one-step fermentation manner, so that the yield of 2-KLG is finally increased to be 40.3 g / L, that is, the yield is increased by 24.4% when being compared with that of a one-step engineering bacterium of which CutA is not expressed; in addition, due to the thermal resistance of foreign protein, the thermal resistance of the engineering bacterium is further improved. Enzyme cross-linking inside cells can be achieved by expressing the foreign protein CutA, continuous catalytic reaction of a plurality of enzymes can be facilitated, and the method has significance in is one-step fermentation production of vitamin C.

The invention discloses a method for measuring bisphenol A in a product by gas chromatography-mass spectrometry. The method comprises the following steps of: soaking and extracting bisphenol A in a sample with an organic solvent, and then carrying out silanization and derivatization; detecting the bisphenol A in the sample with a gas chromatography-mass spectrometer: setting the temperature of a sample injection port to be 250-300 DEG C, a flow rate to be 0.8-1.5ml / min and the temperature of a port to be 280-300 DEG C; enabling the sample to enter the sample injection port, carrying out temperature programming on the temperature of the chromatographic column from 40-60 DEG C to 250-320 DEG C; and enabling the sample to enter a mass spectrometric detection part through the port to carry out mass spectrometric detection, wherein an electron impact ion source is adopted as the ion source of the mass spectrometric detection, the impact energy of the ion source is 70eV, and the temperature of the ion source is set to be 230-250 DEG C. The method for measuring the bisphenol A in the product has low detection limit, good detection effect, little consumption of analysis solvent and low detection cost.

The invention discloses a method for producing a 2-keto-L-gulonic acid (2-KLG) vitamin C precursor by modifying Escherichia coli and belongs to the field of genetic engineering. In the method, a sorbitol dehydrogenase (SLDH) gene from gluconobacter oxydans, a pyrroloquinoline quinine (PQQ) gene cluster and a sorbose dehydrogenase (SDH) / sorbosone dehydrogenase gene (SNDH) from common ketogulonigenium vulgare are expressed in Escherichia coli by a genetic engineering technique to culture an Escherichia coli engineering strain for producing 2-KLG by sorbitol. At present, a two-step fermentationprocess adopted for industrial production of vitamin C in China has the problems of complicated process, many influencing factors, difficult accurate control and large raw material and energy consumption for growing three kinds of microbes at the same time. When the production of the 2-KLG by sorbitol fermentation by the E.coli engineering bacteria is adopted, the production process is simplified, raw materials and energy are saved, and the yield of the 2-KLG can reach 87g / L; and thus, the method has a very bright application prospect.

The invention provides automatic installation equipment and an installation method for a cantilever of a high-speed rail overhead line system. The automatic installation equipment comprises a cantilever assembly template, wherein the cantilever assembling template comprises a template platform, a flat cantilever mounting assembly and an inclined cantilever mounting assembly are arranged on the upper portion of the template platform, the flat cantilever mounting assembly and the inclined cantilever mounting assembly each comprise a clamping piece, and each clamping piece comprises an insulatorclamping piece body used for clamping an insulator and a cantilever clamping piece body used for clamping a cantilever; two cantilever fixing supports, wherein each cantilever fixing support is fixedon a supporting column and comprises a base which connected with the supporting column, and a double-lug clamping device corresponding to a single-lug connecting hole in the insulator is arranged on the base; and a mechanical arm used for carrying the cantilever assembling template to a stand column to be fixedly connected with the double-lug clamping devices of the cantilever fixing supports. Theautomatic installation equipment has the main advantages of labor saving, accurate installation, automatic alignment and high mechanization level.

The invention is concerned with a kind of vacuum load switch for high voltage fixed type switchboard, relating to upside wire of switch, insulated switch, insulated knife frame, vacuum interrupter, downside move contactor, downside wire frame, united terminal, cable leading line plank, insulated knife insulated perch assemblage, interrupter insulated perch assemblage, operation frame and grounding equipment. The insulated switch connects with vacuum interrupter, the insulated knife insulated perch assemblage and interrupter insulated perch assemblage connect with operation frame, and the insulated knife frame, vacuum interrupter and downside wire frame are closed together. The hinge end of insulated switch has contact spring that connects with insulated switch and insulated knife frame. The move end of vacuum interrupter has contact spring that connects with downside move contactor and downside wire frame. This invention has large insulated strength and modularization level, and the simple using is fit for production on scaled.

The invention relates to a method and reagent for determining hydroxyproline in a feed. The method comprises the following steps: preprocessing a to-be-measured sample, and hydrolyzing a protein in the to-be-measured sample; determining the content of hydroxyproline in a hydrolysate of the protein by using an ion exchange chromatography method, wherein a first eluant used for separation with a cation exchange column is a solution with the solvent of water and solutes and the concentration respectively comprising 0.02-0.03 mol / L of sodium citrate, 0.075-0.125 mol / L of sodium chloride, 0.075-0.125 mol / L of citric acid, 12-16% (volume fraction) of ethanol. With improvement of preparation of mobile phase reagents and the instrumental analysis method, the method is suitable for rapid detectionof hydroxyproline. The method can separate hydroxyproline from other amino acids completely and have rapid and accurate characteristics. The method can accurately analyze hydroxyproline in the feed, can be used for large-scale sample detection and is suitable for standardization.

The invention discloses a complete dropper prefabrication platform for a high speed railway overhead line system. The complete dropper prefabrication platform includes a rotatable fixing rod, a hydraulic clamp, a fixing block, a graduated scale, wire clippers, a sliding module and extrusion flat steel, the tip of the hydraulic clamp is welded and fixed at the top of the platform, the rotatable fixing rod is positioned on one side of the hydraulic clamp, the graduated scale is positioned on the other side of the hydraulic clamp, the sliding module is positioned on one side of the graduated scale and parallel to the graduated scale, the wire clippers are positioned on the side, far from the graduated scale, of the sliding module, and the wire clippers are fixed on the side, far from the rotatable fixing rod, of the hydraulic clamp. Through the reasonable layout of the hydraulic clamp, the wire clippers, the fixing block, the graduated scale, the sliding module and other functional modules on the platform, a complete dropper for the overhead line system is fabricated conveniently and accurately; since the whole prefabrication process is simple and easy to learn, an ordinary worker is capable of mastering the crimping essentials in 10 min and performing prefabrication independently, so that the efficiency and quality of the complete dropper prefabrication construction are enhanced. The complete dropper prefabrication platform is suitable for standardized and industrialized production.

The invention relates to the field of food processing, in particular to spicy and hot seasoner. The spicy and hot seasoner has the advantages that quick-frying flavor is prominent, the spicy and hot flavor is natural and pure, color and luster are red and bright, and the spicy and hot seasoner lures the appetite. By means of a quality stability destruction test for the product, the spicy and hot seasoner has a very good color state and very good flavor stability and is very suitable for standard and industrial production. The spicy and hot seasoner combines tradition with delicacy, adapts to the rapid pace of life of modern people, meets the requirements of people for convenience, delicacy and nutrition and achieves the dining standard and industrial purpose.

The invention relates to the field of microelectronics and in particular to a high-power LED linear constant-current driving control chip comprising a DC bus, a plurality of LED lamp beads in series and parallel relationships, and a plurality of external power tubes, wherein the DC bus is connected to the first end of a first LED lamp bead and the drain of a JFET; the gate of the JFET is grounded;the source of the JFET is connected to the input end of a power splitter; the VDD output end of the power splitter is used as a power supply of other function modules inside the chip; the GV output end of the power splitter is connected to the first end of a thermistor and the gate of the external power tube; and the reference voltage output end of a band-gap reference module is connected to thereference voltage input end of the power splitter and the positive input end of a first operational amplifier. The high-power LED linear constant-current driving control chip improves the reliabilityof the whole system by using dual temperature protection design. A cascode structure composed of the external power MOS transistor and the in-chip internal power adjustment transistor reduces uselesspower consumption and improves the efficiency of the whole system.

The invention discloses a semiliquid in-vitro tissue culture and rapid propagation method for MuSa basjoo. According to the method, a semiliquid induction medium comprises an MS culture solution, 6-BA with the concentration of 4 mg / L, NAA with the concentration of 0.15 mg / L, sucrose with the concentration of 30 g / L, activated carbon with the concentration of 0.5 g / L and agar with the concentration of 3 g / L, explants are cultured in a constant-temperature shaking incubator with the shaking frequency of 30 times per minute under the conditions that pH is 5.6-5.8, the temperature is 28-30 DEG C, the illumination intensity is 1,600-2,000 lx and the illumination time of 8 h / d; a multiplication subculture medium mainly comprises the MS culture solution, 6-BA with the concentration of 3 mg / L, NAA with the concentration of 0.15 mg / L and the activated carbon with the concentration of 0.5 g / L; a rooting medium mainly comprises the MS culture solution, NAA with the concentration of 0.5 mg / L, IBA with the concentration of 0.1 mg / L and the activated carbon with the concentration of 0.5 g / L. The browning ratio of the MuSa basjoo is reduced, the induced differentiation ratio and the multiplication coefficient are increased remarkably, and the culture period is shortened.

The invention discloses a method for sealing a glass lamp tube and a metal electrode. The method includes the following steps that firstly, a metal ionic layer is implanted on the surface of the glass lamp tube; secondly, a layer of metal film is plated; thirdly, the glass lamp tube and the metal electrode are combined into a whole in a sealing mode through the high-temperature brazing technology with soldering flux. A lamp manufactured with the method has good mechanical strength and air tightness and is suitable for standard batch production.

The invention discloses an inorganic silicate heat insulating refractory and a preparation method thereof. The inorganic silicate heat insulating refractory comprises the following components in part by weight: 5-20 parts of attapulgite, 50-80 parts of meerschaum, 500-700 parts of water, 5-20 parts of ceramic fiber, 5-20 parts of bentonite, 5-20 parts of sodium sulfosuccinate, 5-20 parts of aluminum dihydrogen phosphate, 5-20 parts of sodium silicate, 1-10 parts of light magnesium carbonate, 1-10 parts of titanium oxide, 15-70 parts of expanded perlite, 5-20 parts of cement and 15-20 parts of sodium methyl silicate. The preparation method for the inorganic silicate heat insulating refractory comprises the following steps: stirring the water, the sodium sulfosuccinate and the ceramic fiber at the rotating speed of 20-30 rpm for 5-8 minutes; adding the meerschaum, stirring the mixture at the rotating speed of 50-70 rpm for 30-35 minutes and then adding the aluminum dihydrogen phosphate, the attapulgite, the bentonite, the sodium silicate, the light magnesium carbonate and the titanium oxide; and after 25 minutes, adding rest components and stirring for 10-15 minutes to obtain the required sizing.

The invention discloses a method for detecting a carcinogenic dye in a plastic packaging material, and the method combines high performance liquid chromatography and mass spectrometry. The method adopts the plastic packaging material as an object, sample pretreatment is simple, no special purification treatment is required, the concentration of the high content carcinogenic dye in a target productcan be accurately determined, and the method is suitable for standardization.

The invention provides a simple method for preparing high-purity houghite compounds, which specifically comprises the steps as follows: houghite compounds with different interlayer spacings can be obtained by adjusting the content proportioning of divalent metal and trivalent metal in raw material fluid; and through repeated centrifugal separation washing, a conductivity meter is adopted for monitoring the eluting condations of impure salt so as to obtain the high-purity houghite compound. Compared with the traditional method, the method provided by the invention has the advantages that the reaction conditions are easy to control and operate, high-purity houghite compounds with different interlayer spacings can be obtained, and the method is applicable to standardized and scale industrial production.

The invention discloses a preparation method of a juicy peach juice beverage. The preparation method of the juicy peach juice beverage comprises the following steps of preprocessing of the main material juicy peaches, preprocessing of the auxiliary material grapes, stirring and uniform mixing of raw material components, degasification of juicy peach juice, multiple times of ozone sterilization and automatic packaging and sealing. The preparation method is strict with preprocessing of juicy peaches and can ensure that the guarantee period of the peach juice is prolonged; a small amount of grape juice is added into the peach juice, and the taste of the obtained juicy peach juice can be kept sweeter; through degasification, the oxygen content in the juice can be lowered, juice ingredient oxidation can be avoided, and original color and taste of the peach juice are maintained; no residues are left after ozone sterilization, pesticide residues on the juice peaches and grapes can be degraded, and therefore the beverage is beneficial for health of the human body; the prepared juicy peach juice beverage is pure in taste, simple in processing process and suitable for standard industrial production.

The invention belongs to the field of detection of saccharides and sugar alcohols in the food. An HPLC (high performance liquid chromatography) evaporative light scattering detection process for separating and detecting thirteen saccharides and sugar alcohols simultaneously comprises the following steps: gradiently eluting and separating a mixed standard solution of thirteen saccharides and sugar alcohols on an amino column through a mixed solution of acetonitrile and water as a separated flow phase with the eluting speed of 0.8 to 1.2ml / min; detecting the mixed standard solution after separation through an evaporative light scattering detector; and the detection conditions of the evaporative light scattering detector are as follows: the temperature of a drift tube is 40 to 70 DEG C, the carrier gas is N2, the flow velocity is 0.8 to 1.5l / min, and the gain is 1. The invention provides an analytic process for simultaneously separating and detecting multiple saccharides and sugar alcohols with high efficiency, convenience, low detection limit and high popularity.

The invention relates to a fish-grass symbiotic ecological fish pond and a fishery breeding sewage treatment method, one or more permeable enclosures are arranged in the ecological fish pond, so that at least two subareas are formed in the ecological fish pond; the interior of the permeation enclosure is of a hollow structure and is filled with filler; a plurality of holes are formed in the outer surface of the permeation enclosure; the top end of the permeable enclosure is higher than the normal water level of the ecological pond; and a waterproof foundation structure is arranged below the permeable enclosure. The system is simple in structure, low in energy consumption and easy to operate and maintain, an eco-friendly mode is adopted for construction, feeding of feed can be reduced, and resources are saved; the tail water purification device has a good landscape effect while purifying tail water; a good habitat structure is formed by the permeation enclosure, a good foraging, refuge, inhabiting and breeding place is provided for aquatic animals in water, and the stability of an ecological system in the whole ecological fish pond can be maintained.

The invention discloses a method for establishing an animal model with Lingnan damp-heat syndrome. The method comprises placing a mouse in a damp-heat environment for modeling feeding, and raising themouse for 14-28 days to obtain an animal model, wherein the mouse is fed with feed and packing during feeding, drinking water and the packing are changed every day, the damp-heat environment conditions include a daytime temperature of 34-36 DEG C with humidity of 85-90% for 12 h, and nighttime temperature of 18-22 DEG C with humidity of 55-65% for 12 h. The method for establishing the animal model with Lingnan characteristic damp-heat syndrome is more suitable for the climate, geographical environment and custom culture of the Lingnan area, a modeling method is simpler, modeling stability isgood, repeatability is good, and the operation and control are easy.

The invention discloses a complete dropper prefabrication platform for a high speed railway overhead line system. The complete dropper prefabrication platform includes a rotatable fixing rod, a hydraulic clamp, a fixing block, a graduated scale, wire clippers, a sliding module and extrusion flat steel, the tip of the hydraulic clamp is welded and fixed at the top of the platform, the rotatable fixing rod is positioned on one side of the hydraulic clamp, the graduated scale is positioned on the other side of the hydraulic clamp, the sliding module is positioned on one side of the graduated scale and parallel to the graduated scale, the wire clippers are positioned on the side, far from the graduated scale, of the sliding module, and the wire clippers are fixed on the side, far from the rotatable fixing rod, of the hydraulic clamp. Through the reasonable layout of the hydraulic clamp, the wire clippers, the fixing block, the graduated scale, the sliding module and other functional modules on the platform, a complete dropper for the overhead line system is fabricated conveniently and accurately; since the whole prefabrication process is simple and easy to learn, an ordinary worker is capable of mastering the crimping essentials in 10 min and performing prefabrication independently, so that the efficiency and quality of the complete dropper prefabrication construction are enhanced. The complete dropper prefabrication platform is suitable for standardized and industrialized production.

The invention discloses a method for derivatization chromatographic analysis of residue semicarbazide in flour and a flour product. The method comprises the following steps: (1) enabling semicarbazide and a derivatization reagent to react, using HPLC / UV (High Performance Liquid Chromatography / Ultra Violet) to detect, and drawing to obtain a standard curve, wherein the standard curve takes the concentration of semicarbazideas an x-coordinate and takes the characteristic peak area of a derivatization product as a y-coordinate; (2) taking a to-be-detected sample, implementing ultrasonic extraction by using an extraction agent, centrifuging to obtain a supernate, adding the derivatization reagent and a precipitator into the supernate, centrifuging to obtain a supernate, filtering the supernate through an organic filter membrane to obtain a filtrate; (3) detecting the filtrate obtained in the step (2) through HPLC / UV, reading the characteristic peak area of the derivatization product, and contrasting with the standard curve to obtain the content of the semicarbazide in the to-be-detected sample. Compared with the prior art, the derivatization reagent strengthens the ultraviolet absorption of the derivatization product, and the detection is facilitated; in addition, a detection instrument is simple and common, the detection cost is low, the rapid detection of the semicarbazide is facilitated, and the method is applicable to large-scale sample detection and is suitable for standardization.

The invention relates to a curved-surface bow-shaped folded-plate tube shell type heat exchanger. The invention comprises a heater exchanger tube. The heater exchanger tube is connected with tube plate, and is provided inside with a the tube bundle passing through a group of tube holes of the bow-shaped folded plate and are fixed between the tube plates in the way of being parallel to axis; the folded plate is evenly fixed by the drawbar and the distance-fixed tube along the axis parallelly; the drawbar and the distance-fixed tube are fixed on the tube plate, the outer side of which is connected with tube box; the bow-shaped folded plate is the curved-surface bow-shaped folded plate, the outer convex side of which is directed at the inlet of the shell-process fluid; a group of bow-shaped folded plate gaps is arranged in a staggered way at intervals from top to bottom horizontally or from left to right vertically in order to form the circuitous flow channel of the fluid inside the tube. The heat exchanger of the invention has the advantages of improving the flow-speed distribution of the shell-process fluid of the bow-shaped folded plate, effectively increasing the circulation area, reducing 'dead zone', obviously improving the efficiency of the heat exchange and reducing the drop of the pressure in comparison to the flat-plated type bow-shaped folded plate.