77results about "Nitrogen determination" patented technology

A method for determining a urea concentration in an aqueous solution containing urea, includes: hydrolyzing the urea in the aqueous solution, measuring an electric conductivity χ of the aqueous solution, and determining the urea concentration in the aqueous solution from the electric conductivity χ using a correlation between the urea concentration and an electric conductivity.

The invention discloses a construction method for summer corn nitrogen content monitoring model based on canopy spectrum information. According to the method, four kinds of summer corn nitrogen content monitoring models are constructed by taking original spectral reflectivity and first derivative spectrum most sensitive band, an optimal band combination and optimal spectrum index as basis by performing test analysis on the change characteristics of summer corn plant canopy spectral reflectivity in different fertilizing levels by a mini lysimeter, researching the response relation between the summer corn plant canopy spectral reflectivity and a first derivative and nitrogen content thereof, screening a sensitive band for corn canopy nitrogen content monitoring, and determining an optimal band combination is determined, and meanwhile, screening optimal spectral index; the four kinds of summer corn nitrogen content monitoring models are calibrated by model evaluation index, and verification is performed by using field plot test data, so as to confirm an optimal monitoring model. The monitoring model can be used for monitoring the nitrogen content of summer corn in the whole growth period, and has important theoretical and practical meaning for realizing large-scale crop nitrogen content non-destructive monitoring and precise water and fertilizer management.

The invention discloses a printed food freshness intelligent label, a production method and application. The production method of the printed food freshness intelligent label includes the following steps of 1) adding a certain amount of binders to water and stirring until solids are completely dissolved, then adding natural pigment powders, plasticizers and antifoaming agents in sequence, stirringcontinuously and uniformly to carry out pre-dispersion and then fully ball-milling to obtain freshness indicator ink; and 2) printing the freshness indicator ink on printed materials by a printing method, and sealing a layer of organic silicone oil after the imprinting is dried, and thus obtaining the printed food freshness intelligent label. The printed food freshness intelligent label producedby the production method is applied in food packaging of fish, meats and eggs to achieve real-time monitoring of food freshness. The method is simple and convenient, and the printed food freshness intelligent label is natural and non-toxic, good in stability and high sensitive, so that mass production of indicator labels can be achieved and the printed food freshness intelligent label has broad application prospects.

The invention provides a rice leaf nitrogen accumulation remote sensing inversion model. The rice leaf nitrogen accumulation remote sensing inversion model is an extreme random tree model of Python language, and model parameters of the extreme random tree model are further provided. The invention further provides a rice leaf nitrogen accumulation remote sensing inversion method. According to the rice leaf nitrogen accumulation remote sensing inversion model, the nitrogen accumulation amount information of rice leaves can be rapidly and accurately obtained; the difficulty that the characteristic wave band of the rice leaf nitrogen accumulation amount is difficult to determine due to the spectral superposition effect caused by complex rice components is overcome, the precision of the rice leaf nitrogen accumulation amount inversion model is greatly improved, and the model is ingenious in design, simple and convenient in calculation, easy to implement and low in cost and suitable for large-scale popularization and application.

The invention discloses an evaluation method for diet protein intake (DPI) of a chronic kidney disease (CKD) patient. Through research of relationships between a fasting serum blood urea nitrogen / creatinine ratio (BUN / Cr) and a single-time urine urea nitrogen / creatinine ratio (UUN / Cr) of a CKD third-phase patient with a stable illness state, and the diet protein intake (DPI), a DPI simple calculation formula based on the fasting serum BUN / Cr and / or random urine UUN / Cr is established. According to the final calculation formula, it is expected that a traditional method for evaluating the DPI through subsistence of the urine within 24 hours can be replaced by a biochemical detection result of a single-time blood or urine in clinical follow-up. Defects such as complexity, long detection time, poor accuracy, difficult sample subsistence or low patient compliance in the traditional method are overcome. Clinically, the method can be used for clinical follow-up, simple blood drawing or single-time urination, thereby evaluating the DPI. The method can be used for managing the diet protein intake of the CKD patient well, fast and conveniently.

Methods and apparatus (FIG. 4a) are disclosed for selective and very sensitive detection of certain hydrolyzable compounds, especially urea, in water by hydrolyzing said hydrolyzable compounds in a sample of the water to one or more carbon dioxide group compounds and determining the difference in the carbon dioxide content of the water and the hydrolyzed sample using conductivity measurements or other carbon dioxide detector outputs.

The invention discloses a nitrogen fertilizer deficiency rapid detection and precise dressing method applied to wheat field management, which belongs to the field of remote sensing technology monitoring, and comprises the following steps: combining a leaf nitrogen indicator NDVIgb and a biomass indicator MSAVI in the form of a ratio, calculating a linear decision coefficient and a model between a new combination parameter and a leaf nitrogen nutrition index NNI, calculating the nitrogen fertilizer deficiency rapid detection and precise dressing method, synchronously constructing the quantitative relation between the nitrogen deficiency NDA and the NNI, serving the NNI as an association node, determining the quantitative relation between the NDA and the NDVIgb / MSAVI through adoption of a model link and index conversion method, achieving inversion from the remote sensing index NDVIgb / MSAVI to the nitrogen deficiency, and completing rapid nitrogen deficiency detection and precise dressing of wheat field management. The nitrogen nutrition status of crops can be rapidly and accurately monitored in the crop production process, accurate management of nitrogen fertilizer is achieved, the yield and quality of the crops are improved, and the risk of environmental pollution is reduced.

The invention provides a method for measuring soil amino acid nutrition contribution. The method is a method for piecewise fitting by calculus and for quantitative evaluation of amino acid nutrition contribution to plant growth under the microbe existence condition. By combining carbon-nitrogen double labeling technique and principle of calculus, long-term nutrition contribution of amino acid to plant growth is studied in the environment of considering microbiological effect. Thus, the invention provides a method basis for the research on organotrophy. The method is simple to operate, and the culture environment is easy to regulate and control. By the isotope technique, data is accurate and reliable and has high accuracy. Amino acid nutrition contribution to various plants can be studied. Theoretical and technical supports are provided for efficient management of nutrient resources.

The invention discloses a method for determining the content of organic amine. The method comprises the following steps: step 1: determining content w2 of inorganic amine in a sample to be detected by adopting a distillation titration method; step 2: determining content w1 of total amine in the sample to be detected by adopting a Kjeldahl method; and step 3: calculating the content of the organic amine in the sample to be detected, wherein content w3 of the organic amine in the sample to be detected is equal to (w1-w2), and sequences of the step 1 and the step 2 can be exchanged or the step 1 and the step 2 can be carried out simultaneously. Compared with a traditional gas chromatography for determining the content of the organic amine, the method for determining the content of the organic amine has the advantages of relatively low cost and relatively simple operation. Meanwhile, the method also has the advantages of relatively high precision, accurate determination result, good repeatability, environment friendliness and the like, and can be applied to conventional analysis and quality control of the content of the organic amine.

The invention relates to detection of the protein content of single crop seeds and particularly discloses an establishment method for a single corn seed protein detection model. The establishment method comprises the specific steps that the diffuse reflection spectra of a sample are collected, effective wavelengths are selected, processing of smoothing (a nine-point window), first-order differentiation and standardization is carried out in sequence, the partial least square method (PLS) is used for dimensionality reduction, the PLS and a support vector machine method (SVR) are used for modeling, near-infrared spectrum data of an unknown sample is obtained under the same conditions and subjected to the same preprocessing and characteristic extraction, and finally the protein content of the sample is detected with the established quantitative analysis model.

The invention discloses a quality control method for compound platycodon grandiflorum ephedrine syrup. According to the method, problems existing in the conventional compound platycodon grandiflorum ephedrine syrup related preparation quality detection method are improved, and the method mainly comprises the following steps: adding thin-layer chromatography of platycodon grandiflorum, polygala tenuifolia and ephedrine hydrochloride, determining the content of the ephedrine hydrochloride by adopting HPLC (High Performance Liquid Chromatography), and determining the ammonium chloride content by adopting nitrogen determination. The quality control method disclosed by the invention is reasonable in design, accurate, reliable, high in specificity and simple to operate, and then a novel quality control standard of the compound platycodon grandiflorum ephedrine syrup is established, so that the drug quality in production, circulation, usage and other links of the compound platycodon grandiflorum ephedrine syrup can be helped to be effectively controlled, the quality level is improved, the controllable production process is ensured, the clinical using safety is ensured, and a reliable guarantee is stably and exactly provided for curative effects of the product.

The invention provides a near-infrared spectral diagnostic method for nitrogen content of leaves of a rubber tree. The near-infrared spectral diagnostic method comprises the following steps: a first step of selecting leaf samples of the rubber tree; a second step of acquiring spectral data of a near-infrared wave section of the leaf samples of the rubber tree; a third step of pre-processing the leaf samples of the rubber tree, and measuring nitrogen content of the pre-treated leaf samples of the rubber tree; a fourth step of acquiring spectral data of the near-infrared wave section of the leafsamples of the rubber tree to obtain fractional order spectrum; and a fifth step of screening a spectral value which corresponds to the wave section mostly related to the nitrogen content of the leafsamples of the rubber tree in the fractional order spectrum through a competitive self-adaptive weighting algorithm as an independent variable to establish a model; and a sixth step of predicating the nitrogen content of leaves of the rubber tree through the established model.

The invention provides a method for detecting nitrogen in a carburant by a Kjeldahl apparatus. The method comprises the following steps of (1) preparing a test specimen: sieving a to-be-detected sample dried by the air by a sieve screen being 80 meshes; taking out the sample; then putting the sample into a drier for measurement; (2) dissolving the sample by a digestion furnace; (3) performing distillation by the Kjeldahl apparatus and hydrochloric acid titration; (4) performing blank reference experiments; (5) calculating the nitrogen element content. The nitrogen element in the carburant is fast detected through the Kjeldahl apparatus. During the detection, the selectivity is high; simplicity and convenience are realized; the speed is high; the accuracy is realized; the method is applicable to the detection of nitrogen elements of a great number of samples in a wide range.

The invention discloses an alkalifying and diluting device for preventing sample blasting boiling of a kjeldahl nitrogen determination instrument and a method. The device comprises a digestion tube, a distilling flask communicated with the interior of the digestion tube is installed at an opening formed in the top of the digestion tube, the top of the distilling flask is connected with a condenser in series and then connected with a titration cylinder, the distilling flask is further provided with an alkaline liquid inlet and a water inlet which are connected with an alkaline pump and a water pump respectively, and the water pump and the alkaline pump are controlled by a control device. According to the device, the blasting boiling and alkaline pump crystallizing problems are solved, and the determination precision of the kjeldahl nitrogen determination instrument is improved.

The invention discloses a method for rapidly determining the protein content of a soybean grain. The method comprises the following steps that the soybean grain is preprocessed; the soybean grain is ground and dried and filtered by a 0.5mm sieve, 0.1-0.5g of the soybean grain is weighed and placed in a Kelvin bottle, distilled water and concentrated sulfuric acid are dropped in successively, a mixture is shaken up and placed on a digestion furnace for heating at the heating temperature of 250 DEG C, and when white smoke comes from a digestion liquid in the Kelvin bottom, the heating temperature is set at 330-380 DEG C; when the digestion liquid is in uniform brown black, the Kelvin bottom taken down, cooled for 3-5 min and then added with 6-8 drops of hydrogen peroxide, the Kelvin bottom is shaken continuously, the above is repeated for 3-5 times, and the liquid is heated for 5-10 min after being colorless and clear, and then taken down and cooled; after cooling, the volume is fixed to1L by means of distilled water, and is filtered by filtered paper into a Erlenmeyer flask to serve as a liquid to be tested; and a flow injection analyzer is used to determine the content of nitrogen. Thus, the protein content in the soybean grain can be determined conveniently, rapidly and accurately in a batch manner.

The invention discloses a forest soil carbon reserve research method which includes the steps: collecting samples including arbor, shrub, herbal, dry branches and fallen leaves and soil; detecting andanalyzing the carbon content of the collected sample to obtain the proportional relation of the carbon content of the arbor, the shrub, the herbal, the dry branches and fallen leaves and the soil; and detecting and analyzing to obtain the distribution characteristics of the carbon content of the community and the change of the carbon cycle of the quercus liaotungensis forest region in the Ziwuling mountain. According to the forest soil carbon reserve research method, the main problems of existing quercus liaotungensis forest area in the Ziwuling mountain can be known according to analysis ofdetection data, and the problems are that young tree seedlings in the quercus liaotungensis forest area in the Ziwuling mountain are few, shrub and grass under the forest are few, and natural forest renewal is affected, the seedling rate and the preservation rate are extremely low, and the difference of different site conditions is remarkable. Once the forests on the upper layer disappear, oak succession is interrupted, other tree species or shrubs are replaced, and natural renewal of the forests is seriously affected.

The invention discloses an experimental method for researching the response of mulching film degradation characteristics to moisture conditions. The method comprises the following steps: (1) sample culture: burying a sample mulching film into soil of each experimental group with different moisture contents; (2) sample collection; (3) sample determination: determining the degradation rate of the mulching film, the surface structure of the mulching film, the chemical structure of the mulching film, soil microbial biomass carbon, nitrogen, soil enzyme activity and the like; and (4) result analysis. According to the invention, a landfill culture test of the mulching film is carried out; the degradation time and the degradation degree of different PBAT biodegradable mulching films are analyzed;the degradation characteristics of the PBAT biodegradable mulching film under different soil moisture conditions are researched by combining scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis, the influence of the PBAT biodegradable mulching film on soil microorganisms and enzyme activity is discussed, a mulching film degradation evaluation method is established, and a theoretical basis is provided for the popularization and application of the biodegradable mulching film.

The invention provides a set of perfect rice dumpling quality evaluation system, which comprises a method for selecting special rice for rice dumplings and a method for screening core indexes. Selection of the special rice for the glutinous rice balls comprises selection of glutinous rice raw materials, determination of main components of glutinous rice, determination of gelatinization characteristics of the glutinous rice, preparation of quick-frozen glutinous rice balls, cooking treatment of the quick-frozen glutinous rice balls and determination of texture of the glutinous rice balls. The core index screening method of the special rice for the rice dumplings comprises the following steps: extracting principal components of rice dumpling quality, calculating comprehensive scores of the rice dumpling quality, performing clustering analysis on the comprehensive scores of the rice dumplings and formulating comprehensive evaluation standards of the rice dumplings. The method solves the problem of uneven varieties and qualities of raw material glutinous rice used by the glutinous rice balls, defines a glutinous rice ball special-purpose glutinous rice quality evaluation system, and provides a unified screening method for glutinous rice ball high-quality special-purpose rice. According to the system, core indexes influencing the quality of the glutinous rice balls are exactly provided and are used as references for evaluating the quality of the glutinous rice balls, and a theoretical basis is provided for ensuring the production efficiency and the eating quality of glutinous rice ball products.

The invention discloses a method for quickly, easily and conveniently measuring the contents of proteins in fruiting bodies of clavicipitaceae fungus stromata. The method includes steps of collecting cordyceps powder samples, carrying out near infrared spectrum scanning on the samples and acquiring spectra to obtain original spectra of samples of calibration sets; preprocessing the original spectra of the samples of the calibration sets; carrying out principle component analysis on information data of the preprocessed original spectra of the samples of the calibration sets and extracting feature information data; chemically detecting the contents of proteins of samples of the fruiting bodies of the clavicipitaceae fungus stromata to obtain chemical measurement values; setting the chemical measurement values as calibration values, utilizing the feature information data as independent variables, utilizing the calibration values as dependent variables and building calibration models by the aid of partial least squares processes; carrying out internal cross-validation and external cross-validation on the calibration models and evaluating the reliability of the calibration models. The method has the advantages of high detection speed, multiple detection samples, low detection cost, accurate detection results and zero pollution.

For an automated determination of a ammonia nitrogen content in a liquid sample, an analyzer and method are provided. The following steps are performed by the method: generating a reagent solution by electrolysis that contains hypochlorite ions to be added to the liquid sample, and feeding the reagent solution into the liquid sample; feeding at least one other reagent solution into the liquid sample and generating a reaction mixture from the reagent solutions and the liquid sample; sensing a measuring signal with a photometric measuring device that correlates with a measuring variable of the reaction mixture; and on the basis of the measuring signal, determining a measuring value for the ammonia nitrogen content with an electronic control device.

The invention discloses a method for determining the nitrogen contents of different organs of a plant. The method comprises the following steps of taking a plant sample, separating according to organs, drying the sample, grinding and sieving, acquiring a reflectivity spectrum of the powder sample by using a hyperspectral camera, meanwhile, determining the nitrogen content in the sample by adoptinga Kjeldahl determination method, and establishing a spectral prediction model of the nitrogen content. According to the method, different organs of the wheat plant are subjected to nitrogen content determination, and an organ-specific nitrogen content prediction model is established, so that research on nitrogen transfer among the organs can be carried out in a targeted manner. According to the method, the spectral camera is used for acquiring reflectivity spectral data, so that the requirement on the sample amount is low, multiple groups of samples can be simultaneously collected, and the detection flux is improved. According to the method, prediction model construction is carried out by adopting an unprocessed original spectrum, and model construction is carried out by adopting an opensource algorithm, so that the spectrum analysis threshold is simplified, and the spectrum technology can be better applied to the technical field of agriculture.

The invention discloses a method for testing protein in tobacco and tobacco products through an automatic azotometer. Samples of tobacco and tobacco products containing about 30-60 mg of protein are weighed accurately and put into a conical flask with the capacity of 300 mL, and 75 mL of a 0.5% acetic acid solution is added and heated and kept boiling for 15 min. Suction filtration is conducted quickly in a vacuum suction filtration device through quantitative filter paper, the conical flask and precipitates are washed with a 0.5% acetic acid solution until filtrate is colorless, and then the filter paper and the precipitates are transferred to a digestive tube. 1.5 g of K2SO4 and 0.15 g of CuSO4*5H20 are added to the digestive tube, 15 mL of concentrated sulfuric acid is added, and the digestive tube is put on a digestive apparatus, heated to 420 DEG C and kept at the temperature for 1 h until digestion is finished. After being cooled to the room temperature, the digestive tube is put on the automatic azotometer for testing of the content of protein.

The invention belongs to the technical field of measurement, and discloses a fillet freshness detection method based on a portable near-infrared spectrometer and the spectrometer. The portable near-infrared spectrometer is used for spectrum acquisition, total volatile basic nitrogen (TVB-N) is measured by virtue of a Kjeldahl determination method. A mathematical model between the spectral data andthe measured TVB-N content is built through a chemometrics method,variable selection is carried out by using a three-step combination strategy, a TVB-N value is predicted through the established model, and the freshness of the fillets is evaluated according to the TVB-N value. The defects of large volume, complicated operation, inconvenient carrying and the like of a laboratory near-infrared spectrometer are solved, the detection can be carried out anytime and anywhere, and the operation is simple and convenient. In addition, a three-step combination strategy is used for variable selection, and data show that the method can obtain a result superior to that of a single algorithm and two-step combination.

The invention belongs to the technical field of measurement, and discloses a straw nitrogen adsorption measurement method and device. The straw nitrogen adsorption measurement method comprises the steps of simulating field flowing water to scour straws through a dynamic adsorption device, and carrying out the dynamic measurement of the adsorption capacity of the straws for ammonium nitrogen. According to the invention, the nitrogen adsorption performance of the straws is used as a starting material; a method of combining static adsorption and dynamic adsorption is adopted; microcosmic surfacemorphology and surface functional group changes of the straws before and after nitrogen adsorption are analyzed, influence factors of the two kinds of straws on ammonium nitrogen adsorption and adsorption thermodynamics and adsorption kinetics research of the straws on nitrogen are discussed, an adsorption thermodynamics model and an appropriate kinetic model are established, and an adsorption mechanism of the adsorption thermodynamics model and the appropriate kinetic model is speculated. The adsorption characteristics of the straws to the ammonium nitrogen are determined, the fertilizer retention capacities of the two straws to the ammonium nitrogen fertilizer in the early stage of water and fertilizer combination are evaluated, and the mechanism of adsorbing the ammonium nitrogen by thetwo straws is preliminarily revealed.

The invention provides a water area ecological health state detection method. The method comprises the following steps: firstly, partitioning a water area to be explored, collecting soil and a water sample respectively, and recording community information; acquiring an environment forecast value by using the soil and the water sample, acquiring a biological diversity index by using the community information, calculating a water area ecological health state index in conjunction with the parameters above, and partitioning the water area to be explored according to the index lastly. By adopting the water area ecological health state detection method provided by the invention, water plants and zooplankton biocenosis in the water area are taken as one reference, meanwhile environment indexes of water and soil in the water area are analyzed in a combination way, the water area ecological health state is analyzed and forecasted by using clustering analysis and main component analysis, and the water and ecological health state can be embodied subjectively.

The invention discloses a quick prediction method for the total nitrogen content of a liquid dung sample in a whole-chain step of liquid dung treatment for a large-scale dairy farm. According to the method, a typical planting and breeding combination-type large-scale dairy farm is selected, on-site investigation, liquid dung and biogas slurry sampling measurement, spectrum collection and mathematical modeling are combined for the whole-chain step of liquid dung treatment under all dynamical composite influence factors, and a near-infrared diffuse reflection spectrum is adopted for constructionof a prediction model and quick detection for the total nitrogen content of the liquid dung in the whole step; under the condition of meeting the on-site conditions, quantitative prediction is quickly and accurately conducted, a conventional monitoring procedure is replaced, an effective technical method is provided for solving the problem, of difficult returning of the liquid dung to the field,of any large-scale dairy farm, and the technical support is provided for promoting green transformation and development of the dairy industry.

The invention relates to the field of a splash-proof tube for an azotometer, in particular to a splash-proof tube device for a fully automatic azotometer. The splash-proof tube device comprises a splash-proof tube main body, an upper cover detachably arranged at the upper part of the splash-proof tube main body and a bottom seal ring, wherein a gas outlet cover, a gas inlet and a gas outlet are formed in the upper cover; the gas outlet cover is located at the joint of the upper cover and the splash-proof tube main body; a splash-proof interlayer is arranged at the lower part of the splash-proof tube main body; the lower end of the gas inlet is communicated with a guide tube, and the guide tube penetrates through the splash-proof interlayer and penetrates to the outside of the bottom seal ring. The upper cover and the splash-proof tube main body are connected through a 360-degree mounting hole and rotate freely in 360 degrees foreach stage of mounting every 45 degrees; a seal ring is arranged at the bottom of the gas outlet cover; the guide tube is provided withtwo liquid charging ports on the splash-proof interlayer, and the liquid charging ports are communicated withambient pressure; casings of the splash-proof tube main body and the upper cover are both prepared from double-layer modified polypropylene through one-step molding.

The invention relates to a plasticizer production wastewater total nitrogen testing method. The method comprises the following steps of 1, sucking waste liquid by using a transfer pipette or weighingwaste residues, and putting the waste liquid or the waste residues into a distillation flask filled with distilled water, 2, connecting the distillation flask with a distillation device, enabling thedistillation device to be connected with a beaker through a condensation pipe, containing sulfuric acid liquid in the beaker, and enabling a glass tube at the tail end of the condenser tube to be inserted into the sulfuric acid liquid, 3, adding a sodium hydroxide solution into the distillation flask, and carrying out heating distillation on the distillation flask until two thirds of the solutionin the distillation flask is evaporated, washing the condenser pipe with distilled water, and introducing the washing liquid after washing into the beaker, 4, adding a methyl red methylene blue mixedindicator into the beaker, and titrating the residual sulfuric acid solution in the beaker by using a sodium hydroxide solution until the sulfuric acid solution is changed into grey green from red purple, and 5, calculating the total nitrogen content. Compared with the prior art, the plasticizer production wastewater total nitrogen testing method is simple, is not influenced by COD in the wastewater and metal ion interference, and is high in repeatability and accuracy, and has a wide application range.