Objective: to analyze the accuracy of clinical blood biochemical test samples and the single factor influence in the process of sample analysis. Methods: the blood biochemical test samples from January 2021 to Februar...Objective: to analyze the accuracy of clinical blood biochemical test samples and the single factor influence in the process of sample analysis. Methods: the blood biochemical test samples from January 2021 to February 2022 in our hospital were studied. A total of 2100 samples were screened and sorted out, and the final test results were analyzed, which were influenced by the sample analysis process, and the results were abnormal or inaccurate. Review the single factor in the inspection process, and explore the causes of its influence. Results: among the data results of the final blood biochemical test specimens, there were 64 abnormal errors, accounting for 3.05%. By analyzing the influence of different single factors, it is found that the main single factors are the preservation of blood samples, the ratio of anticoagulants to samples, and the collection method of blood samples. Among them, the most frequent occurrence is the collection of blood samples, with a total of 49 cases, accounting for 2.33%. Conclusion: during the biochemical examination of patients blood samples in hospitals, the staff who need to collect blood have a high standard of working ability and can treat each blood sample seriously, so as to enhance the accuracy and reliability of the results of biochemical examination for doctors disease diagnosis. Different influencing factors have different solutions.展开更多
Based on methods such as stochastic frontier production function,this paper analyses the changes of single factor productivity(SFP)and total factor productivity(TFP)of agriculture in the five Central Asian countries,d...Based on methods such as stochastic frontier production function,this paper analyses the changes of single factor productivity(SFP)and total factor productivity(TFP)of agriculture in the five Central Asian countries,during the period of 1992 to 2017.The research results show that the agricultural output in most of the five Central Asian countries has increased steadily,while agricultural labor productivity has shown a growth trend.With the exception of Kazakhstan,the land productivity of the other four countries shows a growth trend.In terms of factor input,the number of agricultural workers in the five Central Asian countries mainly shows a trend of decrease,with the input of chemical fertilizer increasing,and the amount of agricultural machinery increasing or decreasing within a small range.The total factor productivity in the five Central Asian countries has improved,but it is still at a low level.The policy suggestions contained in the research conclusions are as follows:(1)Promote the growth of agricultural TFP in the five Central Asian countries,and strengthen the emphasis on the input and allocation of agricultural factors;(2)be aware of the innovation of agricultural technology,as well as the promotion and diffusion of existing agricultural technologies,and improve the overall technical efficiency of agriculture;and(3)accelerate the effective flow of capital and other elements to the agricultural sector,improve infrastructure,better release the'dividend'of science and technology,and enhance the output efficiency.展开更多
Based on analysis of geophysical data such as core observation, rock slices identification, physical property, scanning electron microscope, X-ray diffraction, logging data etc., 16 factors of sedimentation, diagenesi...Based on analysis of geophysical data such as core observation, rock slices identification, physical property, scanning electron microscope, X-ray diffraction, logging data etc., 16 factors of sedimentation, diagenesis, fluid pressure, and their relationships with reservoir physical property were analyzed, and the results indicate sedimentation is the internal factor controlling the reservoir property, diagenesis is the external and final decisive factor and abnormal fluid pressure is an important factor preserving the deep reservoir property. Quantitative characterization of diagenesis indicates that compaction and dissolution are more important than cementation and they respectively cause porosity change of-23.6% and 7.7% and -6.2%. Through optimizing 11 main controlling factors and constructing reservoir evaluation index （REI） according to the hierarchical cluster and principal component analysis, reservoir classification standard was established and reservoirs were divided into four classes. The studies show that Es~ SQ4 consists mainly of class I and II, while Es~ SQ6 is mainly of class III and II; the favorable zone is the north and south slope of Qibei sub-sag and the Liujianfang fault-nose. The successful application of the quantitative and comprehensive evaluation in the Qibei area verifies the advanced, practicable method of less artificial factor is suitable for the low porosity and permeability reservoir.展开更多
This paper used atomic absorption spectrophotometry to determine the content distribution of Cu and Cd in the soil of Duanzhou District,Zhaoqing City.The single factor index method,Nemerow comprehensive index method,p...This paper used atomic absorption spectrophotometry to determine the content distribution of Cu and Cd in the soil of Duanzhou District,Zhaoqing City.The single factor index method,Nemerow comprehensive index method,pollution load index method,geoaccumulation index method,and potential ecological hazard index method were used to analyze the content and pollution status of Cu and Cd in the soil of Duanzhou District,providing a basis for understanding the pollution status of Cu and Cd in the soil of Zhaoqing City.展开更多
Micro-arc oxidation （MAO） process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 to develop compact, smooth and corrosion-resistant coatings on ZK60 Mg alloy by single factor experiments. The ...Micro-arc oxidation （MAO） process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 to develop compact, smooth and corrosion-resistant coatings on ZK60 Mg alloy by single factor experiments. The microstructural characteristics of coatings were investigated by X-ray diffractometry （XRD） and scanning electron microscopy （SEM） coupled with energy dispersive X-ray spectroscopy （EDS）. Test of mass loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The effect of every element in the dual electrolyte system on voltage—time responses during MAO process and the coating characteristic were also analyzed and discussed systematically via single factor experiments. The results reveal that the main components of NaAlO 2 and Na 3 PO 4 as well as additives of NaOH, NaB4O7 and C6H5Na3O7 demonstrate different effects on MAO process and coating characteristics. By means of single factor experiments, an optimized dual electrolyte system was developed, containing 17.5 g/L NaAlO 2, 5.0 g/LNa3 PO4, 5.0 g/L NaOH, 3.0 g/L NaB4O7 and 4.2g/LC6H5Na3O7 .展开更多
The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SN...The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SNWDP）, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus （TP）, permanganate index （CODM,）, dissolved oxygen （DO）, and five-day biochemical oxygen demand （BODs）, and the concentrations of TP, BODs, ammonia nitrogen （NH3--N）, CODM,, DO, and anionic surfactant （Surfa） do not reach the specified standard levels in the tributaries. Seasonal Mann--Kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis （CA） results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.展开更多
In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde m...In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations.The 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression analysis.Minitab (Minitab 15 trial version) and MATLAB (R2010a trial version) were used for data analysis.The t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3),the linear terms of acetone:formaldehyde molar ratio (X1),reaction time (X4) followed by the square effects of acetone/formaldehyde molar ratio (X1X1).The optimized results were achieved with the acetone:formaldehyde molar ratio (mol/mol) at 3:1,solution pH value at 6.0,reaction temperature at 70℃,and reaction time at 140 min,respectively.This method can not only significantly reduce the number and cost of the tests,but also provide a good experimental design strategy for the development of furan resin.The investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.展开更多
To relieve dust pollution in open cut coal mines and reduce the hazards of coal dust pollution to the environment and workers we optimized the synthesis of a dust suppressant by graft copolymerization of environmental...To relieve dust pollution in open cut coal mines and reduce the hazards of coal dust pollution to the environment and workers we optimized the synthesis of a dust suppressant by graft copolymerization of environmentally friendly soy protein isolate with methyl methacrylate.This dust suppressant could effectively control dust pollution in open cut coal mines. The optimized conditions for graft copolymerization in this case were determined by a response surface experiment designed with Design-Expert 10 software. Characterization by scanning electron microscopy showed a significant morphology change of the dust suppressant and the generation of a rigid and dense layer on its surface after interacting with coal dust.The layer exhibited good bonding and dust suppression performance. The analysis with Fourier-transform infrared spectroscopy revealed the appearance of new absorption peaks near 1300, 1072, and 1631 cm, demonstrating effective graft copolymerization. The proposed dust suppressant exhibited excellent wind erosion resistance, with a resistance that exceeded 90% at a wind speed of 6.5 m/sec. The successful graft copolymerization and effective bonding and curing of the dust suppressant on coal dust were experimentally verified.This is of great significance to the control of coal dust pollution.展开更多
Large amounts of heavy metals discharged by industrial cities that are located along the middle reach of Yellow River, China have detrimental impacts on both the ecological environment and human health. In this study,...Large amounts of heavy metals discharged by industrial cities that are located along the middle reach of Yellow River, China have detrimental impacts on both the ecological environment and human health. In this study, fourteen surface sediment samples were taken in the middle reach of the Yellow River. Contents of Zn, Pb, Ni, Cu, Cr, Cd, As were measured, and the pollution status was assessed using three widely used pollution assessment methods, including the single factor index method, Nemerow pollution index method and potential ecological risk index. The concentrations of the studied heavy metals followed the order： Zn 〉 Cr 〉 Cu 〉 Ni 〉 Pb 〉 As 〉 Cd. Nearly 50% of sites had Cu and Cr accumulation. The concentration of Cu at the Yiluo River exceeded the secondary standard value of the Environmental quality standard for soils. Comparison of heavy metal concentrations between this study and other selected rivers indicated that Cu and Cr may be the major pollutants in our case. The single factor index indicated that many samples were at high levels of pollution for Cu and Cd; the Nemerow pollution index indicated that the Yihe River, Luohe River, Yiluo River and Huayuankou were polluted. According to the results of potential ecological risk assessment, Cd in the tributaries of Luo River, Yihe River,and Yiluo River showed high risk toward the ecosystem and human health, Cd in Huanyuankou and Cu in Yiluo River showed a middle level of risk and other samples were at a low level of risk.展开更多
The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid...The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid waste in mining areas,coal gangue occupies a large area and pollutes the surrounding environment during the stacking process.Developing a method of resource utilization is thus a research hotspot.In this study,we modified spontaneous combustion gangue using NaOH,NaCl,and HCl by chemically modifying the minerals.We determined the optimal conditions for treating Fe^(2+) and Mn^(2+) in acid mine drainage with spontaneous combustion gangue and modified coal gangue using the single factor test method.Based on results of the static test,two dynamic test columns,column No.1(spontaneous combustion gangue)and column No.2(NaOH modified spontaneous combustion gangue),were constructed,and the repair effects of acid mine drainage were compared and analyzed using dynamic experiments.The results show that overall,NaOH modified spontaneous combustion gangue is the most efficient at removing the Fe^(2+) and Mn^(2+) in acid mine drainage.The optimal conditions for NaOH modification are an NaOH concentration of 3 mol/L,a liquid to solid ratio of 2 L/kg,and a modification time of 8 h.The overall efficiency of column No.2 at removing Fe^(2+) and Mn^(2+) from acid mine drainage is better than that of column No.1.Among them,the average removal efficiency of Fe^(2+)and Mn^(2+) from acid mine drainage in column No.2 were 97.73%and 44.82%,respectively.The above results show that NaOH modified spontaneous combustion gangue is a good adsorbent,which has application potential in wastewater remediation,as it can achieve the purpose of“treating dust with waste”.展开更多
[ Objective] The content of total antimony （Sb） in fresh fruit was investigated and its pollution was evaluated, to provide the basic data for diet exposure evaluation. [ Method] The content of total Sb in 194 sampl...[ Objective] The content of total antimony （Sb） in fresh fruit was investigated and its pollution was evaluated, to provide the basic data for diet exposure evaluation. [ Method] The content of total Sb in 194 samples was detected by hydride generation-atomic fluorescence spectrometry （HG-AFS）, and the Sb pollution in several fruits was evaluated by the method of single factor pollution index. [ Result ] The mean of total Sb was 0. 005 6 mg/kg, and the median was 0.003 8 mg/kg. The minimum value was not detected while the maximum value was O. 21 mg/kg, and the confidence interval was ND-O. 019 mg/kg （PS-P95）. The medi- ans of total Sb content in different fruits successively were dragon fruit （0.011 0 mg/kg） 〉 kiwi fruit （0.008 0 mg/kg） 〉 peach （0.006 0 mg/kg）. According to the method of single factor pollution index, the index from all samples was less than 0.2, suggesting that the samples involved were under the normal background value. [ Conclusion ] The Sb was detected in all samples but under the background value, and it was concluded that there was no Sb pollution in fresh fruit in Hunan Province.展开更多
A novel redox-responsive PEG-sheddable copolymer of disulfide-linked polyethylene glycol 5000-lysine-di-tocopherol succinate(P_(5k)SSLV)was designed and synthesized.Thin-film hydration method was used to prepare DOX-l...A novel redox-responsive PEG-sheddable copolymer of disulfide-linked polyethylene glycol 5000-lysine-di-tocopherol succinate(P_(5k)SSLV)was designed and synthesized.Thin-film hydration method was used to prepare DOX-loaded P_(5k)SSLV nanomicelle.To optimize the preparation technology,we investigate the effects of dosage,type of organic solvent,hydration temperature and time,and cryoprotectant on drug-loading content,encapsulation efficiency,particle size,and zeta potential.The mean particle size and zeta potential were determined by Zetasizer.The morphology of the P_(5k)SSLV-DOX nanomicelles was visualized by transmission electron microscopy.The drug-loading content and encapsulation efficiency of P_(5k)SSLV-DOX nanomicelle were investigated by UV.The drug-loading content,encapsulation efficiency,particle size,and zeta potential of the final optimized nanomicelles were 4.58%,97.20%,30.21 nm and -0.84 mV,respectively.In addition,the stability of nanomicelles was investigated,which included dilution stability and storage stability.The results showed that P_(5k)SSLV-DOX nanomicelle had good dilution stability and storage stability at 4℃.The preparation method of P_(5k)SSLV-DOX nanomicelle with thinfilm hydration method was practical and simple,which was valuable to be further studied.展开更多
The water quality of rivers flowing into lakes is a reflection of the regional environment and significantly contributes to the nutrient levels of the lake.Based on multi-year monitoring data of the estuarine water qu...The water quality of rivers flowing into lakes is a reflection of the regional environment and significantly contributes to the nutrient levels of the lake.Based on multi-year monitoring data of the estuarine water quality of the Zi River which flows into the Dongting Lake,single factor analysis was performed for the dissolved oxygen,nitrogen ammonia(NH3-N),chemical oxygen demand,total phosphorus,permanganate index,and biochemical oxygen demand.The analysis indicated that the estuarine water quality class was dependent on the NH3-N level.The NH3-N trend of the Zi River was then simulated using an improved grey model IGM(0,N)based on a grey correlation analysis.The IGM(0,N)model produced a smaller average relative error and a more accurate prediction compared with a multiple regression model,thus validating the use of the IGM(0,N)model as a suitable method to simulate the estuarine water quality with a complex multi-factor system.展开更多
This paper studies discrete investment portfolio model that the objective function is utility function. According to a hybrid branch-and-bound method based on Lagrangian relaxation and continuous relaxation, the paper...This paper studies discrete investment portfolio model that the objective function is utility function. According to a hybrid branch-and-bound method based on Lagrangian relaxation and continuous relaxation, the paper analyzes the question using the real statistical data. The results indicate that discrete investment portfolio model really has its guidance in the actual investment.展开更多
[Objectives] To extract the flavonoids from leaves of Coix lacryma-jobi L. [Methods] Ethanol extraction method was adopted,spectrophotometry was used,and single factor experiment and orthogonal experiment were carried...[Objectives] To extract the flavonoids from leaves of Coix lacryma-jobi L. [Methods] Ethanol extraction method was adopted,spectrophotometry was used,and single factor experiment and orthogonal experiment were carried out to study the effects of ethanol percentage,extraction temperature,solid-to-liquid ratio and extraction time on the extraction of total flavonoids from leaves of C. lacryma-jobi L.[Results] The order of 4 factors influencing the extraction of flavonoids from leaves of C. lacryma-jobi L. was: solid-to-liquid ratio > extraction time > ethanol percentage > extraction temperature. When the extraction temperature was 70℃,the extraction time was 1. 5 h and the solid-liquid ratio was 1: 10,the ethanol percentage was 60%,the extraction effect was the best,extraction of flavonoids was 0. 107 5 mg/m L.[Conclusions] This study is expected to provide a theoretical basis for further development and utilization of C. lacryma-jobi L.展开更多
[ Objective ] This study aimed to establish and optimize the ISSR-PCR reaction system and amplification process for Elymus sibiricus L. , to provide sci- entific basis for exploring the genetic diversity of E. sibiric...[ Objective ] This study aimed to establish and optimize the ISSR-PCR reaction system and amplification process for Elymus sibiricus L. , to provide sci- entific basis for exploring the genetic diversity of E. sibiricus germplasm resources. [ Method] Orthogonal design and single factor test were applied to establish the ISSR-PCR reaction system of E. sibiricus, optimize the influencing factors including Taq DNA polymerase, DNA template concentration, Mg2 ＋ , dNTP, primer concentration, and screen the annealing temperature, number of cycles and extension time. [ Result ] The optimal reaction system for ISSR analysis contains 0.2 mmol/L dNTPs, 0.2 μmol/L ISSR primers, 1.5 U of Taq DNA polymerase, 2.5 μl of 10 × PCR Buffer, 1.5 mmol/L MgC12 and 40 ng of template DNA in 25 μl total volume; the amplification was conducted with 35 cycles and extension time of 90 s. [ Conclusion] ISSR-PCR reaction system for E. sibiricus was established and optimized, and then verified using two E. sibiricus germplasrns, demonstrating that the ISSR-PCR reaction system is stable and can be used for the genetic analysis of E. sibiricus.展开更多
[Objectives]This study was conducted to screen best process parameters for making Foshou yam and honey can.[Methods]The Foshou yam produced from Wuxue was used as a raw material to prepare Foshou yam and honey nutriti...[Objectives]This study was conducted to screen best process parameters for making Foshou yam and honey can.[Methods]The Foshou yam produced from Wuxue was used as a raw material to prepare Foshou yam and honey nutritional can by combining Foshou yam with honey through screening,pre-cooking,filling,exhausting,cooling and other technical processes.The optimum technology parameter of Foshou yam and honey nutritional can was studied through single factor tests and response surface optimization.[Results]The optimum technical parameters of Foshou yam and honey nutritional can were citric acid concentration 0.1%,amount of edible salt 0.1%,cooking time 14 min and honey concentration 26%.Under these conditions,the final sensory score was 90.20.The prepared can was not only rich in nutrition,but also had good flavor and taste.[Conclusions]This study provides reference for the development and utilization of Foshou yam and the research and development of functional food.展开更多
[Objectives] The chlorogenic acid in Sambucus chinensis Lindl is a kind of biologically active substance with multiple pharmacological effects, but the content is relatively small. It is of great significance to find ...[Objectives] The chlorogenic acid in Sambucus chinensis Lindl is a kind of biologically active substance with multiple pharmacological effects, but the content is relatively small. It is of great significance to find the best extraction process. Therefore, we designed single factor experiments and orthogonal experiments to screen the best conditions for extracting chlorogenic acid from S. chinensis. [Methods] With ethanol concentration, ultrasonic power, and extraction time as three single factors, single factor experiments were performed on S. chinensis, and its chlorogenic acid content was calculated from a standard curve. The contents of chlorogenic acid obtained under various conditions were compared, and then, orthogonal experiments were designed according to the orthogonal table to analyze the optimal extraction conditions of chlorogenic acid. [Results] The optimal extraction conditions of chlorogenic acid for S. chinensis were: the ethanol concentration 60%, the ultrasonic power 36 W, and the extraction time 40 min.[Conclusions] The factor that had the greatest effect on the extraction rate of chlorogenic acid in S. chinensis was ethanol concentration, followed by extraction time, and the least influencing factor was ultrasonic power. With 60% ethanol solution serving as the extractant, the ultrasonic power of 36 W, and the extraction time of 40 min, a better extraction rate was obtained. These conditions can be used as the best extraction conditions for chlorogenic acid.展开更多
[Objectives]To detect content of Pb,Cd,Hg,As,Cu,Zn,and Cr in Lysimachia christinae,and to analyze the pollution level.[Methods]Seven kinds of elements in L.christinae were determined by Inductively coupled plasma mass...[Objectives]To detect content of Pb,Cd,Hg,As,Cu,Zn,and Cr in Lysimachia christinae,and to analyze the pollution level.[Methods]Seven kinds of elements in L.christinae were determined by Inductively coupled plasma mass spectrometry and analyzed by single index and comprehensive index.[Results]The seven heavy metal elements showed good linearity in their respective concentration ranges.The recoveries of the samples were 84.5%-109.5%,and the RSD values were 2.30%-5.10%.Comparing the measured results of heavy metal elements with the limit values stipulated in the 2020 edition of the Chinese Pharmacopoeia and other standards,the Cr element in 19 batches of samples exceeded the standard,and the Zn element in 7 batches of samples exceeded the standard.The exceeding rates were 100.0%and 36.8%,respectively;the content of other heavy metal elements did not exceed the standard.The order of individual index from large to small was Cr,Zn,Cd,Hg,Cu,As,and Pb,and the average comprehensive pollution level was mild pollution and above.[Conclusions]L.christinae was mainly polluted by Cr,followed by Zn;this study can provide basic data for drafting of the limit standard for heavy metal elements in L.christinae.展开更多
文摘Objective: to analyze the accuracy of clinical blood biochemical test samples and the single factor influence in the process of sample analysis. Methods: the blood biochemical test samples from January 2021 to February 2022 in our hospital were studied. A total of 2100 samples were screened and sorted out, and the final test results were analyzed, which were influenced by the sample analysis process, and the results were abnormal or inaccurate. Review the single factor in the inspection process, and explore the causes of its influence. Results: among the data results of the final blood biochemical test specimens, there were 64 abnormal errors, accounting for 3.05%. By analyzing the influence of different single factors, it is found that the main single factors are the preservation of blood samples, the ratio of anticoagulants to samples, and the collection method of blood samples. Among them, the most frequent occurrence is the collection of blood samples, with a total of 49 cases, accounting for 2.33%. Conclusion: during the biochemical examination of patients blood samples in hospitals, the staff who need to collect blood have a high standard of working ability and can treat each blood sample seriously, so as to enhance the accuracy and reliability of the results of biochemical examination for doctors disease diagnosis. Different influencing factors have different solutions.
基金Strategic Priorily Research Program of the CAS,No.XDA20040400National Natural Science Foundation of China,No.41871184,No.41401203+1 种基金The Agricultural Science and Technology Innovation Program.No.ASTIP-IAHD-2020-01,No.CAAS-ZDRW202012Central Research Institutes of Basic Research and Public Service Special Operations.No.161005202001-2。
文摘Based on methods such as stochastic frontier production function,this paper analyses the changes of single factor productivity(SFP)and total factor productivity(TFP)of agriculture in the five Central Asian countries,during the period of 1992 to 2017.The research results show that the agricultural output in most of the five Central Asian countries has increased steadily,while agricultural labor productivity has shown a growth trend.With the exception of Kazakhstan,the land productivity of the other four countries shows a growth trend.In terms of factor input,the number of agricultural workers in the five Central Asian countries mainly shows a trend of decrease,with the input of chemical fertilizer increasing,and the amount of agricultural machinery increasing or decreasing within a small range.The total factor productivity in the five Central Asian countries has improved,but it is still at a low level.The policy suggestions contained in the research conclusions are as follows:(1)Promote the growth of agricultural TFP in the five Central Asian countries,and strengthen the emphasis on the input and allocation of agricultural factors;(2)be aware of the innovation of agricultural technology,as well as the promotion and diffusion of existing agricultural technologies,and improve the overall technical efficiency of agriculture;and(3)accelerate the effective flow of capital and other elements to the agricultural sector,improve infrastructure,better release the'dividend'of science and technology,and enhance the output efficiency.
文摘Based on analysis of geophysical data such as core observation, rock slices identification, physical property, scanning electron microscope, X-ray diffraction, logging data etc., 16 factors of sedimentation, diagenesis, fluid pressure, and their relationships with reservoir physical property were analyzed, and the results indicate sedimentation is the internal factor controlling the reservoir property, diagenesis is the external and final decisive factor and abnormal fluid pressure is an important factor preserving the deep reservoir property. Quantitative characterization of diagenesis indicates that compaction and dissolution are more important than cementation and they respectively cause porosity change of-23.6% and 7.7% and -6.2%. Through optimizing 11 main controlling factors and constructing reservoir evaluation index （REI） according to the hierarchical cluster and principal component analysis, reservoir classification standard was established and reservoirs were divided into four classes. The studies show that Es~ SQ4 consists mainly of class I and II, while Es~ SQ6 is mainly of class III and II; the favorable zone is the north and south slope of Qibei sub-sag and the Liujianfang fault-nose. The successful application of the quantitative and comprehensive evaluation in the Qibei area verifies the advanced, practicable method of less artificial factor is suitable for the low porosity and permeability reservoir.
基金Fourth Batch of Innovative Research Teams from Zhaoqing University(TD202408)Quality Engineering and Teaching Reform Project of Zhaoqing University in 2024(zlgc 2024002)+1 种基金2024 School-level Course Ideological and Political Reform Demonstration Project of Zhaoqing University(ZHAOXUEYUAN[2024]83)Notice on the List of Projects for the Construction of Teaching Quality and Teaching Reform in Undergraduate Universities in Guangdong Province in 2021(Yue Jiao Gao Han[2021]29).
文摘This paper used atomic absorption spectrophotometry to determine the content distribution of Cu and Cd in the soil of Duanzhou District,Zhaoqing City.The single factor index method,Nemerow comprehensive index method,pollution load index method,geoaccumulation index method,and potential ecological hazard index method were used to analyze the content and pollution status of Cu and Cd in the soil of Duanzhou District,providing a basis for understanding the pollution status of Cu and Cd in the soil of Zhaoqing City.
基金Project(JSAWT-09-02)supported by the Key Laboratory of Advanced Welding Technology of Jiangsu Province,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Micro-arc oxidation （MAO） process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 to develop compact, smooth and corrosion-resistant coatings on ZK60 Mg alloy by single factor experiments. The microstructural characteristics of coatings were investigated by X-ray diffractometry （XRD） and scanning electron microscopy （SEM） coupled with energy dispersive X-ray spectroscopy （EDS）. Test of mass loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The effect of every element in the dual electrolyte system on voltage—time responses during MAO process and the coating characteristic were also analyzed and discussed systematically via single factor experiments. The results reveal that the main components of NaAlO 2 and Na 3 PO 4 as well as additives of NaOH, NaB4O7 and C6H5Na3O7 demonstrate different effects on MAO process and coating characteristics. By means of single factor experiments, an optimized dual electrolyte system was developed, containing 17.5 g/L NaAlO 2, 5.0 g/LNa3 PO4, 5.0 g/L NaOH, 3.0 g/L NaB4O7 and 4.2g/LC6H5Na3O7 .
基金supported by the National Natural Science Foundation of China(Grants No.41101250 and 51309031)the Chinese 12th Five-Year Science and Technology Support Program(Grant No.2012BAC06B00)
文摘The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SNWDP）, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus （TP）, permanganate index （CODM,）, dissolved oxygen （DO）, and five-day biochemical oxygen demand （BODs）, and the concentrations of TP, BODs, ammonia nitrogen （NH3--N）, CODM,, DO, and anionic surfactant （Surfa） do not reach the specified standard levels in the tributaries. Seasonal Mann--Kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis （CA） results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.
文摘In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations.The 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression analysis.Minitab (Minitab 15 trial version) and MATLAB (R2010a trial version) were used for data analysis.The t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3),the linear terms of acetone:formaldehyde molar ratio (X1),reaction time (X4) followed by the square effects of acetone/formaldehyde molar ratio (X1X1).The optimized results were achieved with the acetone:formaldehyde molar ratio (mol/mol) at 3:1,solution pH value at 6.0,reaction temperature at 70℃,and reaction time at 140 min,respectively.This method can not only significantly reduce the number and cost of the tests,but also provide a good experimental design strategy for the development of furan resin.The investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.
基金supported by the National key R & D plan for the 13th five year plan (No. 2017YFC0805200)the Qingdao science and technology plan project (No.19-3-2-6-zhc)+1 种基金the Natural Science Foundation of Shandong Province (No. ZR2019MEE118)the National Natural Science Foundation of China (No. 51974179)。
文摘To relieve dust pollution in open cut coal mines and reduce the hazards of coal dust pollution to the environment and workers we optimized the synthesis of a dust suppressant by graft copolymerization of environmentally friendly soy protein isolate with methyl methacrylate.This dust suppressant could effectively control dust pollution in open cut coal mines. The optimized conditions for graft copolymerization in this case were determined by a response surface experiment designed with Design-Expert 10 software. Characterization by scanning electron microscopy showed a significant morphology change of the dust suppressant and the generation of a rigid and dense layer on its surface after interacting with coal dust.The layer exhibited good bonding and dust suppression performance. The analysis with Fourier-transform infrared spectroscopy revealed the appearance of new absorption peaks near 1300, 1072, and 1631 cm, demonstrating effective graft copolymerization. The proposed dust suppressant exhibited excellent wind erosion resistance, with a resistance that exceeded 90% at a wind speed of 6.5 m/sec. The successful graft copolymerization and effective bonding and curing of the dust suppressant on coal dust were experimentally verified.This is of great significance to the control of coal dust pollution.
基金supported by the National Basic Research Program (973) of China (No. 2015CB453103)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB14020102)the National Natural Science Foundation of China (Nos. 21477150 and 21321004)
文摘Large amounts of heavy metals discharged by industrial cities that are located along the middle reach of Yellow River, China have detrimental impacts on both the ecological environment and human health. In this study, fourteen surface sediment samples were taken in the middle reach of the Yellow River. Contents of Zn, Pb, Ni, Cu, Cr, Cd, As were measured, and the pollution status was assessed using three widely used pollution assessment methods, including the single factor index method, Nemerow pollution index method and potential ecological risk index. The concentrations of the studied heavy metals followed the order： Zn 〉 Cr 〉 Cu 〉 Ni 〉 Pb 〉 As 〉 Cd. Nearly 50% of sites had Cu and Cr accumulation. The concentration of Cu at the Yiluo River exceeded the secondary standard value of the Environmental quality standard for soils. Comparison of heavy metal concentrations between this study and other selected rivers indicated that Cu and Cr may be the major pollutants in our case. The single factor index indicated that many samples were at high levels of pollution for Cu and Cd; the Nemerow pollution index indicated that the Yihe River, Luohe River, Yiluo River and Huayuankou were polluted. According to the results of potential ecological risk assessment, Cd in the tributaries of Luo River, Yihe River,and Yiluo River showed high risk toward the ecosystem and human health, Cd in Huanyuankou and Cu in Yiluo River showed a middle level of risk and other samples were at a low level of risk.
基金This work was supported by the National Natural Science Foundation of China(Nos.51304114,41672247)the Scientific Research Fund of the Liaoning Provincial Education Department(No.LJ2017FAL016).
文摘The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid waste in mining areas,coal gangue occupies a large area and pollutes the surrounding environment during the stacking process.Developing a method of resource utilization is thus a research hotspot.In this study,we modified spontaneous combustion gangue using NaOH,NaCl,and HCl by chemically modifying the minerals.We determined the optimal conditions for treating Fe^(2+) and Mn^(2+) in acid mine drainage with spontaneous combustion gangue and modified coal gangue using the single factor test method.Based on results of the static test,two dynamic test columns,column No.1(spontaneous combustion gangue)and column No.2(NaOH modified spontaneous combustion gangue),were constructed,and the repair effects of acid mine drainage were compared and analyzed using dynamic experiments.The results show that overall,NaOH modified spontaneous combustion gangue is the most efficient at removing the Fe^(2+) and Mn^(2+) in acid mine drainage.The optimal conditions for NaOH modification are an NaOH concentration of 3 mol/L,a liquid to solid ratio of 2 L/kg,and a modification time of 8 h.The overall efficiency of column No.2 at removing Fe^(2+) and Mn^(2+) from acid mine drainage is better than that of column No.1.Among them,the average removal efficiency of Fe^(2+)and Mn^(2+) from acid mine drainage in column No.2 were 97.73%and 44.82%,respectively.The above results show that NaOH modified spontaneous combustion gangue is a good adsorbent,which has application potential in wastewater remediation,as it can achieve the purpose of“treating dust with waste”.
基金Supported by Scientific Research Project of Medicine and Health Care in Hunan Province(B2014-162)Scientific Research Project of Xiangtan Science and Technology Bureau(SF20141003)
文摘[ Objective] The content of total antimony （Sb） in fresh fruit was investigated and its pollution was evaluated, to provide the basic data for diet exposure evaluation. [ Method] The content of total Sb in 194 samples was detected by hydride generation-atomic fluorescence spectrometry （HG-AFS）, and the Sb pollution in several fruits was evaluated by the method of single factor pollution index. [ Result ] The mean of total Sb was 0. 005 6 mg/kg, and the median was 0.003 8 mg/kg. The minimum value was not detected while the maximum value was O. 21 mg/kg, and the confidence interval was ND-O. 019 mg/kg （PS-P95）. The medi- ans of total Sb content in different fruits successively were dragon fruit （0.011 0 mg/kg） 〉 kiwi fruit （0.008 0 mg/kg） 〉 peach （0.006 0 mg/kg）. According to the method of single factor pollution index, the index from all samples was less than 0.2, suggesting that the samples involved were under the normal background value. [ Conclusion ] The Sb was detected in all samples but under the background value, and it was concluded that there was no Sb pollution in fresh fruit in Hunan Province.
文摘A novel redox-responsive PEG-sheddable copolymer of disulfide-linked polyethylene glycol 5000-lysine-di-tocopherol succinate(P_(5k)SSLV)was designed and synthesized.Thin-film hydration method was used to prepare DOX-loaded P_(5k)SSLV nanomicelle.To optimize the preparation technology,we investigate the effects of dosage,type of organic solvent,hydration temperature and time,and cryoprotectant on drug-loading content,encapsulation efficiency,particle size,and zeta potential.The mean particle size and zeta potential were determined by Zetasizer.The morphology of the P_(5k)SSLV-DOX nanomicelles was visualized by transmission electron microscopy.The drug-loading content and encapsulation efficiency of P_(5k)SSLV-DOX nanomicelle were investigated by UV.The drug-loading content,encapsulation efficiency,particle size,and zeta potential of the final optimized nanomicelles were 4.58%,97.20%,30.21 nm and -0.84 mV,respectively.In addition,the stability of nanomicelles was investigated,which included dilution stability and storage stability.The results showed that P_(5k)SSLV-DOX nanomicelle had good dilution stability and storage stability at 4℃.The preparation method of P_(5k)SSLV-DOX nanomicelle with thinfilm hydration method was practical and simple,which was valuable to be further studied.
基金the Research Project of Education Department of Hunan Province(19C0026,ZJGB2020078)。
文摘The water quality of rivers flowing into lakes is a reflection of the regional environment and significantly contributes to the nutrient levels of the lake.Based on multi-year monitoring data of the estuarine water quality of the Zi River which flows into the Dongting Lake,single factor analysis was performed for the dissolved oxygen,nitrogen ammonia(NH3-N),chemical oxygen demand,total phosphorus,permanganate index,and biochemical oxygen demand.The analysis indicated that the estuarine water quality class was dependent on the NH3-N level.The NH3-N trend of the Zi River was then simulated using an improved grey model IGM(0,N)based on a grey correlation analysis.The IGM(0,N)model produced a smaller average relative error and a more accurate prediction compared with a multiple regression model,thus validating the use of the IGM(0,N)model as a suitable method to simulate the estuarine water quality with a complex multi-factor system.
基金Supported by the Key Project of Science and Technology Department of Henan Province(122102210060)
文摘This paper studies discrete investment portfolio model that the objective function is utility function. According to a hybrid branch-and-bound method based on Lagrangian relaxation and continuous relaxation, the paper analyzes the question using the real statistical data. The results indicate that discrete investment portfolio model really has its guidance in the actual investment.
基金Supported by Project of National Natural Science Foundation(81360684)Natural Science Foundation Project of Guangxi(2011GXNSFA018046)+3 种基金the 12th Five-Year TCM Key Discipline Chinese Medicine Chemistry Construction Program of State Administration of Traditional Chinese Medicine(Guo Zhong Yi Yao Ren Jiao Fa[2012]32)Key Discipline Chinese Medicine Chemistry Construction Program of Guangxi(Gui Jiao Ke Yan[2013]16)Program of Key Laboratory of Guangxi Universities on National Medicine in Youjiang River Basin(Gui Jiao Ke Yan[2014]14)Student’s Platform for Innovation and Entrepreneurship Training Program of Guangxi in 2015(201510599026)
文摘[Objectives] To extract the flavonoids from leaves of Coix lacryma-jobi L. [Methods] Ethanol extraction method was adopted,spectrophotometry was used,and single factor experiment and orthogonal experiment were carried out to study the effects of ethanol percentage,extraction temperature,solid-to-liquid ratio and extraction time on the extraction of total flavonoids from leaves of C. lacryma-jobi L.[Results] The order of 4 factors influencing the extraction of flavonoids from leaves of C. lacryma-jobi L. was: solid-to-liquid ratio > extraction time > ethanol percentage > extraction temperature. When the extraction temperature was 70℃,the extraction time was 1. 5 h and the solid-liquid ratio was 1: 10,the ethanol percentage was 60%,the extraction effect was the best,extraction of flavonoids was 0. 107 5 mg/m L.[Conclusions] This study is expected to provide a theoretical basis for further development and utilization of C. lacryma-jobi L.
基金Supported by Project of Collection,Cataloguing and Utilization of Perennial Forage Grass Germplasm Resources(NB2012-2130135-33)Conservation Project for Forage Grass Germplasm Resources
文摘[ Objective ] This study aimed to establish and optimize the ISSR-PCR reaction system and amplification process for Elymus sibiricus L. , to provide sci- entific basis for exploring the genetic diversity of E. sibiricus germplasm resources. [ Method] Orthogonal design and single factor test were applied to establish the ISSR-PCR reaction system of E. sibiricus, optimize the influencing factors including Taq DNA polymerase, DNA template concentration, Mg2 ＋ , dNTP, primer concentration, and screen the annealing temperature, number of cycles and extension time. [ Result ] The optimal reaction system for ISSR analysis contains 0.2 mmol/L dNTPs, 0.2 μmol/L ISSR primers, 1.5 U of Taq DNA polymerase, 2.5 μl of 10 × PCR Buffer, 1.5 mmol/L MgC12 and 40 ng of template DNA in 25 μl total volume; the amplification was conducted with 35 cycles and extension time of 90 s. [ Conclusion] ISSR-PCR reaction system for E. sibiricus was established and optimized, and then verified using two E. sibiricus germplasrns, demonstrating that the ISSR-PCR reaction system is stable and can be used for the genetic analysis of E. sibiricus.
基金2018 Undergraduate Innovation and Entrepreneurship Training Program of Huanggang Normal University(201810514045)High-level Cultivation Project of Huanggang Normal University(201816703)。
文摘[Objectives]This study was conducted to screen best process parameters for making Foshou yam and honey can.[Methods]The Foshou yam produced from Wuxue was used as a raw material to prepare Foshou yam and honey nutritional can by combining Foshou yam with honey through screening,pre-cooking,filling,exhausting,cooling and other technical processes.The optimum technology parameter of Foshou yam and honey nutritional can was studied through single factor tests and response surface optimization.[Results]The optimum technical parameters of Foshou yam and honey nutritional can were citric acid concentration 0.1%,amount of edible salt 0.1%,cooking time 14 min and honey concentration 26%.Under these conditions,the final sensory score was 90.20.The prepared can was not only rich in nutrition,but also had good flavor and taste.[Conclusions]This study provides reference for the development and utilization of Foshou yam and the research and development of functional food.
文摘[Objectives] The chlorogenic acid in Sambucus chinensis Lindl is a kind of biologically active substance with multiple pharmacological effects, but the content is relatively small. It is of great significance to find the best extraction process. Therefore, we designed single factor experiments and orthogonal experiments to screen the best conditions for extracting chlorogenic acid from S. chinensis. [Methods] With ethanol concentration, ultrasonic power, and extraction time as three single factors, single factor experiments were performed on S. chinensis, and its chlorogenic acid content was calculated from a standard curve. The contents of chlorogenic acid obtained under various conditions were compared, and then, orthogonal experiments were designed according to the orthogonal table to analyze the optimal extraction conditions of chlorogenic acid. [Results] The optimal extraction conditions of chlorogenic acid for S. chinensis were: the ethanol concentration 60%, the ultrasonic power 36 W, and the extraction time 40 min.[Conclusions] The factor that had the greatest effect on the extraction rate of chlorogenic acid in S. chinensis was ethanol concentration, followed by extraction time, and the least influencing factor was ultrasonic power. With 60% ethanol solution serving as the extractant, the ultrasonic power of 36 W, and the extraction time of 40 min, a better extraction rate was obtained. These conditions can be used as the best extraction conditions for chlorogenic acid.
基金Supported by Risk Monitoring Task Project of Chongqing Drug Administration in 2020。
文摘[Objectives]To detect content of Pb,Cd,Hg,As,Cu,Zn,and Cr in Lysimachia christinae,and to analyze the pollution level.[Methods]Seven kinds of elements in L.christinae were determined by Inductively coupled plasma mass spectrometry and analyzed by single index and comprehensive index.[Results]The seven heavy metal elements showed good linearity in their respective concentration ranges.The recoveries of the samples were 84.5%-109.5%,and the RSD values were 2.30%-5.10%.Comparing the measured results of heavy metal elements with the limit values stipulated in the 2020 edition of the Chinese Pharmacopoeia and other standards,the Cr element in 19 batches of samples exceeded the standard,and the Zn element in 7 batches of samples exceeded the standard.The exceeding rates were 100.0%and 36.8%,respectively;the content of other heavy metal elements did not exceed the standard.The order of individual index from large to small was Cr,Zn,Cd,Hg,Cu,As,and Pb,and the average comprehensive pollution level was mild pollution and above.[Conclusions]L.christinae was mainly polluted by Cr,followed by Zn;this study can provide basic data for drafting of the limit standard for heavy metal elements in L.christinae.
