Two-Line Element(TLE)datasets are the only orbital data source of Earth-orbiting space objects for many civil users for their research and applications.The datasets have uneven qualities that may affect the reliabilit...Two-Line Element(TLE)datasets are the only orbital data source of Earth-orbiting space objects for many civil users for their research and applications.The datasets have uneven qualities that may affect the reliability of the propagated positions of space objects using a single TLE.The least squares approach to use multiple TLEs also suffers from the poor quality of some TLEs,and reliable error information cannot be available.This paper proposes a simplex algorithm to estimate an optimal TLE from multiple TLEs and obtain the uncertainty of each element.It is a derivative-free technique that can deal with various orbit types.Experiments have demonstrated that using the TLE estimated from the simplex method is more reliable,stable,and effective than those from the batch least squares method.As an application example,the optimal TLE and its uncertainty are used for predicting the fallen area,keeping the actual fallen site in the prediction areas.展开更多
[ Objective] To study the effects of different pretreatment methods on determination of microelement in feed and thus find the best pre treatment method for each microetement, t Method] The samples （concentrated feed...[ Objective] To study the effects of different pretreatment methods on determination of microelement in feed and thus find the best pre treatment method for each microetement, t Method] The samples （concentrated feeding stuff and fodder） were pretreated through throe methods, that is, dry incineration method, HNOs HCIO, wetdecomposition method and microwave digestion method. Then the content of seven kinds of mi croelement （AI, Ca, Cu, Fe, Mn, Se and Zn） was determined by inductively coupled plasma atomic emission spectrometer （ICPAES）. I Result] These three methods were all suitable for the determination of Cu, Mn and Zn in concentrated feeding stuff and the determination of Cu and Ca in fodder. The content of Cu and Ca was higher in fodder detected by HNO3 HCIO, wetdecomposition method. The microwave digestion method was suitable for the determination of AI and Ca in concentrated feeding stuff and the determination of AI, Fe, Mn and Zn in fodder. The dry incinera tion method was fit for the determination of Fe in concentrated feeding stuff. [ Condusionl The content of different microelements should be deter mined after the feed is treated with different Ioretreatment methods.展开更多
According to the response relationship between landscape and water resource,the selection principle of important landscapes was determined from the perspectives of nature and history in this study,and determination me...According to the response relationship between landscape and water resource,the selection principle of important landscapes was determined from the perspectives of nature and history in this study,and determination methods or steps of important landscapes along the mainstream of Yellow River were also established to select important landscapes that should be protected.展开更多
The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for par...The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for part steps of the original method.It is obscure that the 80% sulfuric acid solution,acted as the extraction solution in the determination of TEP,is prepared based on a volume ratio or mass ratio.Furthermore,the change of solubility of recently available Gum Xanthan(GX) from the market means that the original protocol is no longer applicable,and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX.We found that different preparation techniques could result in the varied concentrations of 80% H_(2)SO_(4).The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve,which caused different correction results of TEP.The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis.The extraction capacities of H_(2)SO_(4) with different concentrations for Alcian Blue were distinct,but had limited effect on the final measuring result of TEP.The change of the standard curve slope came along with the variation of shaking time,which markedly altered the detection limit and calibration result,and the extended shaking time was in favor of the determination of low-concentration TEP.It was suggested that the extraction solution concentration,shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations.展开更多
High performance liquid chromatographic method was developed valdated and applied for the simultaneous determi- nation of lisinopril and NSAIDs in bulk, pharmaceuticals formulations and human serum. A Purospher star C...High performance liquid chromatographic method was developed valdated and applied for the simultaneous determi- nation of lisinopril and NSAIDs in bulk, pharmaceuticals formulations and human serum. A Purospher star C18 (5 μm, 25 × 0.46 cm) column was used with mobile phase consisting of methanol: water: acetonitrile (80:17.5:2.5 v/v, pH 3.0) and quantitative evaluation was performed at 225 nm with a flow rate of 1.0 mL?min–1. The retention time of lisinopril was 2.2 min while naproxen, flurbiprofen, diclofenac sodium and mefenamic acid were found to be 4.0, 4.5, 5.0 and 6.7 min respectively. Suitability of this method for the quantitative determination of the drugs was proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) guidelines. The method is selective, precise, accurate and can be used for analysis of pharmaceutical preparations in quality control and clinical laboratories.展开更多
A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is est...A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is established. By conditional experiments, the optimum analytical conditions and parameters are obtained. Levenberg-Marquart (L-M) algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively. The results of standard addition method show that for the tap water, the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%, and the RSD is in the range of 0.23%-0.98%; for the Yellow River water (Lijin district of Shandong Province), the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%, and the RSD is in the range of 0.13%-2.52%; for the seawater in Qingdao offshore, the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%, and the RSD is in the range of 0.14%-2.66%. It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions. This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water. By using the established ANN- catalytic spectrophotometric method, the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of iron and manganese are drawn.展开更多
Background： Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility（AID） of starch i...Background： Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility（AID） of starch in different grain legume cultivars for pigs by means of both a polarimetric and enzymatic method for starch determination.Methods： Three experiments were conducted with six barrows each which were fitted with ileal T-cannulas. In total, 18 diets including six different cultivars of faba beans（Vicia faba L.） and peas（Pisum sativum L.）, five different cultivars of lupins（Lupinus luteus L., Lupinus angustifolius L.）, and one diet with a soybean meal（SBM） were fed.Results： The starch content of faba beans and peas was greater（P ＆lt; 0.05） when determined polarimetrically than enzymatically（438 vs. 345 g/kg dry matter（DM） in faba beans and 509 vs. 390 g/kg DM in peas, respectively）.Considerable lower starch contents were obtained in lupins and SBM, with 82 and 48 g/kg DM（analyzed polarimetrically） and ＆lt;1.1 and 3 g/kg DM（analyzed enzymatically）, respectively. Mean values for contents of neutral detergent fiber（NDF） and acid detergent fiber（ADF） in grain legumes ranged from 111 and 79 g/kg DM in peas to248 and 207 g/kg DM in lupins, respectively. Contents of condensed tannins in the colored flowered faba bean cultivars ranged from 2.1 to 7.4 g/kg DM. The AID of starch was greater（P ＆lt; 0.05） in pea than in faba bean cultivars,and using the polarimetric starch determination method resulted in greater（P ＆lt; 0.05） digestibility values than using enzymatic starch analysis（84 vs. 80% in faba beans and 86 vs. 83% in peas）. Moreover, AID of starch differed（P ＆lt; 0.05）within pea cultivars and starch digestibility in faba beans decreased linearly（P ＆lt; 0.05） as the content of condensed tannins increased. However, there was no relationship between contents of NDF and ADF and AID of starch in pea and faba bean cultivars.Conclusion： Both contents and AID of starch in grain legumes can vary as influenced by the analytical method used for starch determination. Generally, starch digestibility is greater when measured by polarimetric rather than enzymatic methods.展开更多
GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon ...GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.展开更多
[Objectives] To study on colorimetric method and content determination of total phenol in homemade plum wine. [Methods]The optimal determination condition of total polyphenols content in plum wine( commercially availa...[Objectives] To study on colorimetric method and content determination of total phenol in homemade plum wine. [Methods]The optimal determination condition of total polyphenols content in plum wine( commercially available and homemade) by Folin-Ciocalteu method was inspected,and commercially available and homemade plum wine was evaluated by the method. [Results]The optimal determination conditions of total polyphenols content: sample dose of 1. 0 m L,Folin-Ciocalteu reagent of 1 m L,4% Na_2CO_3 solution of 4. 0 m L,reaction temperature of 50 ℃,reaction time of 1. 5 h,and determination wavelength of 756 nm. Absorbance showed good linear relationship with total polyphenols content within the range of 17. 73-59. 12 μg/m L( y = 14. 878 x + 0. 0739,R^2= 0. 9998). Recovery rate of adding standard sample was between 98. 8% and 103. 5%,and relative standard deviation was 2. 0%( n = 5). [Conclusions]The method had high precision degree and good stability,which was suitable for measuring total polyphenols content in plum wine( commercially available and homemade).展开更多
Purpose:It is necessary to determine whether the value of network information exists or not from users’perspective.This study is to develop a new approach,called'double-proportion'method(DPM),to determine the...Purpose:It is necessary to determine whether the value of network information exists or not from users’perspective.This study is to develop a new approach,called'double-proportion'method(DPM),to determine the point of information obsolescence.Design/methodology/approach:Firstly,DPM is produced and introduced with statistics in great detail.Secondly,two data sets from Qiangguo Forum and NetEase News are used to validate DPM.Finally,the distributions of lifetime of the two sets are compared and reasons for the differences are revealed.Findings:In Qiangguo Forum,posts with no comments within 17 h can be identified as obsolescence,which indicates that approximately 83%of posts information has died within24 h,92%died within 36 h and almost all died within 54 h;While in NetEase News,news without comments within 28 h can be identified as obsolescence.Research limitations:This study adopted comments as the only behavior indicator,for further study other indicators like page views,republished times need to be used,to exploit better solutions for information obsolescence.Practical implications:According to obsolescence determination,network managers can optimize webpages more rationally,delete aged information in time,preserve valuable information,help search engines ignore aged webpages,optimize reptiles’mechanisms,and help advertisers choose webpages rationally to advertise online.Originality/value:Firstly,DPM is designed from users’perspective to describe the lifetime of information;Secondly,DPM is easy to use.DPM merges and improves former methods by taking the long-tail theory and Pareto principle into consideration.展开更多
This paper focuses on the stochastic analysis of a viscoelastic bistable energy harvesting system under colored noise and harmonic excitation, and adopts the time-delayed feedback control to improve its harvesting eff...This paper focuses on the stochastic analysis of a viscoelastic bistable energy harvesting system under colored noise and harmonic excitation, and adopts the time-delayed feedback control to improve its harvesting efficiency. Firstly, to obtain the dimensionless governing equation of the system, the original bistable system is approximated as a system without viscoelastic term by using the stochastic averaging method of energy envelope, and then is further decoupled to derive an equivalent system. The credibility of the proposed method is validated by contrasting the consistency between the numerical and the analytical results of the equivalent system under different noise conditions. The influence of system parameters on average output power is analyzed, and the control effect of the time-delayed feedback control on system performance is compared. The output performance of the system is improved with the occurrence of stochastic resonance(SR). Therefore, the signal-to-noise ratio expression for measuring SR is derived, and the dependence of its SR behavior on different parameters is explored.展开更多
Curcuma wenyujin has been widely used as a traditional medicine in China. In this paper a strategy for the quantitative determination of the polysaccharide by a phenol-sulfuric acid method was described. Involved in t...Curcuma wenyujin has been widely used as a traditional medicine in China. In this paper a strategy for the quantitative determination of the polysaccharide by a phenol-sulfuric acid method was described. Involved in three factors, 5% phenol volume, H2SO4 volume, and temperature of water bath, we adopted the L9（3）3 orthogonal array design to gain the optimal colorimetric method. 3.0 ml of polysaccharide solution, 1.0 ml, 5% phenol and 7.0 ml H2SO4 were mixed with constant stirring in a glass vessel, and then kept in a water bath at 40 ℃. After cooling to room temperature for 20 min, the absorbance values were recorded by the UV-2501 PC spectrometer at the wavelength range of 485 nm. The polysaccharide content in Curcuma wenyujin were 3.21%, 3.23%, 3.20%, 3.18~/0, 3.22% and 2.38%, respectively. All results showed that this method was adequate, valid and applicable, may be applied to the determination of other bacterial polysaccharide as well.展开更多
dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultan...dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultaneous determination of uranium and thorium without prior separation. Various molar ratios of uranium/thorium, from 0.5∶1 to 10∶1, can be determined with satisfactory precision and accuracy. Uranium and thorium content in a phosphate ore and simulated sample were determined, the recoveries were 98.4%～102.5% for uranium and 96.8%～102.3% for thorium, the relative standard deviations (R.S.D) were 1.5%～2.3% for uranium and 2.1%～3.1% for thorium.展开更多
Degradation rate of feed proteins in rumen is a basic indicator of new intestinal protein system of ruminants. In this paper, determination methods of degradation rate in tureen including in-vivo method, nylon bag met...Degradation rate of feed proteins in rumen is a basic indicator of new intestinal protein system of ruminants. In this paper, determination methods of degradation rate in tureen including in-vivo method, nylon bag method and artificial rumen method are compared in order to provide a reference for animal nutrition.展开更多
In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball ...In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.展开更多
[Objectives]To establish a new method for indirect determination of bisoprolol fumarate based on fluorescence quenching technology.[Methods]In ammonia water and ammonium chloride buffer solution at pH=9.2,whenλexcita...[Objectives]To establish a new method for indirect determination of bisoprolol fumarate based on fluorescence quenching technology.[Methods]In ammonia water and ammonium chloride buffer solution at pH=9.2,whenλexcitation=277 nm andλemission=596 nm,with the increase of CCu2+,the fluorescence signal intensity of bisoprolol fumarate weakened,and the difference between the fluorescence intensity of bisoprolol fumarate itself and the fluorescence intensity of the test solution after the quencher Cu2+was added(ΔF)and Cbisoprolol fumarate showed a good linear relationship.[Results]In the range of 15.39-76.93μg/mL,ΔF=146.7 Cbisoprolol fumarate+482.1,r=0.9988,and the detection limit is 0.1391μg/mL.[Conclusions]The fluorescence quenching method has been applied to the determination of actual samples with a recovery rate of 99.9%and an RSD of 2.7%.The results are satisfactory.展开更多
Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food produ...Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.展开更多
[Objective]This study was to establish a rapid,specific and simple method for quantitative determination of tetrachlorantraniliprole by 1H NMR.[Method]1H NMR spectroscopy was acquired with deuterium DMSO as the solven...[Objective]This study was to establish a rapid,specific and simple method for quantitative determination of tetrachlorantraniliprole by 1H NMR.[Method]1H NMR spectroscopy was acquired with deuterium DMSO as the solvent and maleic acid as internal standard under the conditions of temperature 25℃,pulses width 8.0μs,delay time 5 s,and scanning times 8.[Result]The hydrogen proton peaks of tetrachlorantraniliprole(δ=10.55)and maleic acid(δ=6.27)were taken as quantitative peaks.The peak area ratio y(As/Ar)and mass ratio x(ms/mr)were linearly regressed,and the correlation coefficient was 0.9999.The RSD value of repeatability test was 0.38%,and the RSD value of stability test was 0.77%.The content of tetrachlorantraniliprole was determined as 99.6%.[Conclusion]1H NMR spectroscopy can be used for quantitative determination of tetrachlorantraniliprole without standard reference,which is rapid,accurate and simple.展开更多
基金supported by Chongqing Municipal Natural Science Foundation of General Program(CSTB2022NSCQMSX1093)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202200701)China Postdoctoral Science Foundation(2021M703487).
文摘Two-Line Element(TLE)datasets are the only orbital data source of Earth-orbiting space objects for many civil users for their research and applications.The datasets have uneven qualities that may affect the reliability of the propagated positions of space objects using a single TLE.The least squares approach to use multiple TLEs also suffers from the poor quality of some TLEs,and reliable error information cannot be available.This paper proposes a simplex algorithm to estimate an optimal TLE from multiple TLEs and obtain the uncertainty of each element.It is a derivative-free technique that can deal with various orbit types.Experiments have demonstrated that using the TLE estimated from the simplex method is more reliable,stable,and effective than those from the batch least squares method.As an application example,the optimal TLE and its uncertainty are used for predicting the fallen area,keeping the actual fallen site in the prediction areas.
文摘[ Objective] To study the effects of different pretreatment methods on determination of microelement in feed and thus find the best pre treatment method for each microetement, t Method] The samples （concentrated feeding stuff and fodder） were pretreated through throe methods, that is, dry incineration method, HNOs HCIO, wetdecomposition method and microwave digestion method. Then the content of seven kinds of mi croelement （AI, Ca, Cu, Fe, Mn, Se and Zn） was determined by inductively coupled plasma atomic emission spectrometer （ICPAES）. I Result] These three methods were all suitable for the determination of Cu, Mn and Zn in concentrated feeding stuff and the determination of Cu and Ca in fodder. The content of Cu and Ca was higher in fodder detected by HNO3 HCIO, wetdecomposition method. The microwave digestion method was suitable for the determination of AI and Ca in concentrated feeding stuff and the determination of AI, Fe, Mn and Zn in fodder. The dry incinera tion method was fit for the determination of Fe in concentrated feeding stuff. [ Condusionl The content of different microelements should be deter mined after the feed is treated with different Ioretreatment methods.
基金Supported by Modern Water Science Innovation Project of Ministry of Water Resources(XD2004-03-05)Key Project for National Science and Technology Supporting Plan during the Eleventh Five-Year Plan(2006BAB06B08-04)~~
文摘According to the response relationship between landscape and water resource,the selection principle of important landscapes was determined from the perspectives of nature and history in this study,and determination methods or steps of important landscapes along the mainstream of Yellow River were also established to select important landscapes that should be protected.
基金The National Key Research and Development Project of China under contract No.2019YFC1407805the National Natural Science Foundation of China under contract Nos 41876134, 41676112 and 41276124+1 种基金the Tianjin 131 Innovation Team Program under contract No.20180314the Changjiang Scholar Program of Chinese Ministry of Education under contract No.T2014253。
文摘The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for part steps of the original method.It is obscure that the 80% sulfuric acid solution,acted as the extraction solution in the determination of TEP,is prepared based on a volume ratio or mass ratio.Furthermore,the change of solubility of recently available Gum Xanthan(GX) from the market means that the original protocol is no longer applicable,and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX.We found that different preparation techniques could result in the varied concentrations of 80% H_(2)SO_(4).The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve,which caused different correction results of TEP.The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis.The extraction capacities of H_(2)SO_(4) with different concentrations for Alcian Blue were distinct,but had limited effect on the final measuring result of TEP.The change of the standard curve slope came along with the variation of shaking time,which markedly altered the detection limit and calibration result,and the extended shaking time was in favor of the determination of low-concentration TEP.It was suggested that the extraction solution concentration,shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations.
文摘High performance liquid chromatographic method was developed valdated and applied for the simultaneous determi- nation of lisinopril and NSAIDs in bulk, pharmaceuticals formulations and human serum. A Purospher star C18 (5 μm, 25 × 0.46 cm) column was used with mobile phase consisting of methanol: water: acetonitrile (80:17.5:2.5 v/v, pH 3.0) and quantitative evaluation was performed at 225 nm with a flow rate of 1.0 mL?min–1. The retention time of lisinopril was 2.2 min while naproxen, flurbiprofen, diclofenac sodium and mefenamic acid were found to be 4.0, 4.5, 5.0 and 6.7 min respectively. Suitability of this method for the quantitative determination of the drugs was proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) guidelines. The method is selective, precise, accurate and can be used for analysis of pharmaceutical preparations in quality control and clinical laboratories.
文摘A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is established. By conditional experiments, the optimum analytical conditions and parameters are obtained. Levenberg-Marquart (L-M) algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively. The results of standard addition method show that for the tap water, the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%, and the RSD is in the range of 0.23%-0.98%; for the Yellow River water (Lijin district of Shandong Province), the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%, and the RSD is in the range of 0.13%-2.52%; for the seawater in Qingdao offshore, the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%, and the RSD is in the range of 0.14%-2.66%. It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions. This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water. By using the established ANN- catalytic spectrophotometric method, the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of iron and manganese are drawn.
基金supported by the H.W.Schaumann Stiftung(Hamburg,Germany)
文摘Background： Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility（AID） of starch in different grain legume cultivars for pigs by means of both a polarimetric and enzymatic method for starch determination.Methods： Three experiments were conducted with six barrows each which were fitted with ileal T-cannulas. In total, 18 diets including six different cultivars of faba beans（Vicia faba L.） and peas（Pisum sativum L.）, five different cultivars of lupins（Lupinus luteus L., Lupinus angustifolius L.）, and one diet with a soybean meal（SBM） were fed.Results： The starch content of faba beans and peas was greater（P ＆lt; 0.05） when determined polarimetrically than enzymatically（438 vs. 345 g/kg dry matter（DM） in faba beans and 509 vs. 390 g/kg DM in peas, respectively）.Considerable lower starch contents were obtained in lupins and SBM, with 82 and 48 g/kg DM（analyzed polarimetrically） and ＆lt;1.1 and 3 g/kg DM（analyzed enzymatically）, respectively. Mean values for contents of neutral detergent fiber（NDF） and acid detergent fiber（ADF） in grain legumes ranged from 111 and 79 g/kg DM in peas to248 and 207 g/kg DM in lupins, respectively. Contents of condensed tannins in the colored flowered faba bean cultivars ranged from 2.1 to 7.4 g/kg DM. The AID of starch was greater（P ＆lt; 0.05） in pea than in faba bean cultivars,and using the polarimetric starch determination method resulted in greater（P ＆lt; 0.05） digestibility values than using enzymatic starch analysis（84 vs. 80% in faba beans and 86 vs. 83% in peas）. Moreover, AID of starch differed（P ＆lt; 0.05）within pea cultivars and starch digestibility in faba beans decreased linearly（P ＆lt; 0.05） as the content of condensed tannins increased. However, there was no relationship between contents of NDF and ADF and AID of starch in pea and faba bean cultivars.Conclusion： Both contents and AID of starch in grain legumes can vary as influenced by the analytical method used for starch determination. Generally, starch digestibility is greater when measured by polarimetric rather than enzymatic methods.
文摘GB/T 13245-91 1 Theme and Scope This standard specifies the method abstract, reagents, apparatus, specimen, analyzing procedure, result calculation and permissible tolerance used for determination of the total carbon with combustion gravimetric method.
基金Supported by Sichuan Science and Technology Support Plan(2015FZ0026)Postgraduate Innovation Project of Southwest University for Nationalities(CX2016SZ016)
文摘[Objectives] To study on colorimetric method and content determination of total phenol in homemade plum wine. [Methods]The optimal determination condition of total polyphenols content in plum wine( commercially available and homemade) by Folin-Ciocalteu method was inspected,and commercially available and homemade plum wine was evaluated by the method. [Results]The optimal determination conditions of total polyphenols content: sample dose of 1. 0 m L,Folin-Ciocalteu reagent of 1 m L,4% Na_2CO_3 solution of 4. 0 m L,reaction temperature of 50 ℃,reaction time of 1. 5 h,and determination wavelength of 756 nm. Absorbance showed good linear relationship with total polyphenols content within the range of 17. 73-59. 12 μg/m L( y = 14. 878 x + 0. 0739,R^2= 0. 9998). Recovery rate of adding standard sample was between 98. 8% and 103. 5%,and relative standard deviation was 2. 0%( n = 5). [Conclusions]The method had high precision degree and good stability,which was suitable for measuring total polyphenols content in plum wine( commercially available and homemade).
基金supported by the National Social Science Foundation of China(Grant No.12CTQ025)the National Natural Science Foundation of China(Grant No.70833005)
文摘Purpose:It is necessary to determine whether the value of network information exists or not from users’perspective.This study is to develop a new approach,called'double-proportion'method(DPM),to determine the point of information obsolescence.Design/methodology/approach:Firstly,DPM is produced and introduced with statistics in great detail.Secondly,two data sets from Qiangguo Forum and NetEase News are used to validate DPM.Finally,the distributions of lifetime of the two sets are compared and reasons for the differences are revealed.Findings:In Qiangguo Forum,posts with no comments within 17 h can be identified as obsolescence,which indicates that approximately 83%of posts information has died within24 h,92%died within 36 h and almost all died within 54 h;While in NetEase News,news without comments within 28 h can be identified as obsolescence.Research limitations:This study adopted comments as the only behavior indicator,for further study other indicators like page views,republished times need to be used,to exploit better solutions for information obsolescence.Practical implications:According to obsolescence determination,network managers can optimize webpages more rationally,delete aged information in time,preserve valuable information,help search engines ignore aged webpages,optimize reptiles’mechanisms,and help advertisers choose webpages rationally to advertise online.Originality/value:Firstly,DPM is designed from users’perspective to describe the lifetime of information;Secondly,DPM is easy to use.DPM merges and improves former methods by taking the long-tail theory and Pareto principle into consideration.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11902081)the Science and Technology Projects of Guangzhou (Grant No. 202201010326)the Guangdong Provincial Basic and Applied Basic Research Foundation (Grant No. 2023A1515010833)。
文摘This paper focuses on the stochastic analysis of a viscoelastic bistable energy harvesting system under colored noise and harmonic excitation, and adopts the time-delayed feedback control to improve its harvesting efficiency. Firstly, to obtain the dimensionless governing equation of the system, the original bistable system is approximated as a system without viscoelastic term by using the stochastic averaging method of energy envelope, and then is further decoupled to derive an equivalent system. The credibility of the proposed method is validated by contrasting the consistency between the numerical and the analytical results of the equivalent system under different noise conditions. The influence of system parameters on average output power is analyzed, and the control effect of the time-delayed feedback control on system performance is compared. The output performance of the system is improved with the occurrence of stochastic resonance(SR). Therefore, the signal-to-noise ratio expression for measuring SR is derived, and the dependence of its SR behavior on different parameters is explored.
文摘Curcuma wenyujin has been widely used as a traditional medicine in China. In this paper a strategy for the quantitative determination of the polysaccharide by a phenol-sulfuric acid method was described. Involved in three factors, 5% phenol volume, H2SO4 volume, and temperature of water bath, we adopted the L9（3）3 orthogonal array design to gain the optimal colorimetric method. 3.0 ml of polysaccharide solution, 1.0 ml, 5% phenol and 7.0 ml H2SO4 were mixed with constant stirring in a glass vessel, and then kept in a water bath at 40 ℃. After cooling to room temperature for 20 min, the absorbance values were recorded by the UV-2501 PC spectrometer at the wavelength range of 485 nm. The polysaccharide content in Curcuma wenyujin were 3.21%, 3.23%, 3.20%, 3.18~/0, 3.22% and 2.38%, respectively. All results showed that this method was adequate, valid and applicable, may be applied to the determination of other bacterial polysaccharide as well.
文摘dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultaneous determination of uranium and thorium without prior separation. Various molar ratios of uranium/thorium, from 0.5∶1 to 10∶1, can be determined with satisfactory precision and accuracy. Uranium and thorium content in a phosphate ore and simulated sample were determined, the recoveries were 98.4%～102.5% for uranium and 96.8%～102.3% for thorium, the relative standard deviations (R.S.D) were 1.5%～2.3% for uranium and 2.1%～3.1% for thorium.
文摘Degradation rate of feed proteins in rumen is a basic indicator of new intestinal protein system of ruminants. In this paper, determination methods of degradation rate in tureen including in-vivo method, nylon bag method and artificial rumen method are compared in order to provide a reference for animal nutrition.
文摘In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.
基金Project for Improving Basic Research Ability of Middle Aged and Young Teachers in Colleges and Universities of Guangxi in 2017(2017KY0284)Project of Guangxi Key Laboratory of Zhuang and Yao Ethnic Medicine(GXZYKF2019-7)+2 种基金Program of Key Laboratory for Extraction and Purification and Quality Analysis of TCM in 2017(J1700208)Project of Guangxi University of Chinese Medicine(YB14004)Collaborative Innovation Center of Zhuang and Yao Ethnic Medicine([2013]No.20).
文摘[Objectives]To establish a new method for indirect determination of bisoprolol fumarate based on fluorescence quenching technology.[Methods]In ammonia water and ammonium chloride buffer solution at pH=9.2,whenλexcitation=277 nm andλemission=596 nm,with the increase of CCu2+,the fluorescence signal intensity of bisoprolol fumarate weakened,and the difference between the fluorescence intensity of bisoprolol fumarate itself and the fluorescence intensity of the test solution after the quencher Cu2+was added(ΔF)and Cbisoprolol fumarate showed a good linear relationship.[Results]In the range of 15.39-76.93μg/mL,ΔF=146.7 Cbisoprolol fumarate+482.1,r=0.9988,and the detection limit is 0.1391μg/mL.[Conclusions]The fluorescence quenching method has been applied to the determination of actual samples with a recovery rate of 99.9%and an RSD of 2.7%.The results are satisfactory.
文摘Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.
文摘[Objective]This study was to establish a rapid,specific and simple method for quantitative determination of tetrachlorantraniliprole by 1H NMR.[Method]1H NMR spectroscopy was acquired with deuterium DMSO as the solvent and maleic acid as internal standard under the conditions of temperature 25℃,pulses width 8.0μs,delay time 5 s,and scanning times 8.[Result]The hydrogen proton peaks of tetrachlorantraniliprole(δ=10.55)and maleic acid(δ=6.27)were taken as quantitative peaks.The peak area ratio y(As/Ar)and mass ratio x(ms/mr)were linearly regressed,and the correlation coefficient was 0.9999.The RSD value of repeatability test was 0.38%,and the RSD value of stability test was 0.77%.The content of tetrachlorantraniliprole was determined as 99.6%.[Conclusion]1H NMR spectroscopy can be used for quantitative determination of tetrachlorantraniliprole without standard reference,which is rapid,accurate and simple.
