[Objective] The aim was to study the aromas composition of plum fruit. [Method] The aroma components of six kinds of plum fruits were analyzed by SPME, detected and identified by GC-MS.[Result] 85 kinds of aroma subst...[Objective] The aim was to study the aromas composition of plum fruit. [Method] The aroma components of six kinds of plum fruits were analyzed by SPME, detected and identified by GC-MS.[Result] 85 kinds of aroma substances were separated and identified, including 40 kinds of common components.The experiments had good reproducibility by strictly controlling the desorption temperature, time and sample holding time.The obtained chromatographic peak retention time and the normalized area variation coefficient CV% values were between 0.03% -0.54% and 5.85% -18.08% by experimenting the five precision of AoLi13.The qualitative and quantitative were fully meet repeatability requirements for test samples. [Conclusion] The study provided scientific basis for the development and process of plum industry in China.展开更多
This paper presents a new method of improving Global Positioning System(GPS)positioning precision. Based on the altitude hold mode, the method does not need any other equipment. Under this constraint condition, the To...This paper presents a new method of improving Global Positioning System(GPS)positioning precision. Based on the altitude hold mode, the method does not need any other equipment. Under this constraint condition, the Total Least Squares(TLS) algorithm is used to prove that the method is effective. Theoretical analysis shows that the algorithm can significantly improve the GPS positioning precision.展开更多
The objective of the present study was to determine the proper sources and concentrations of soybean lecithin （phosphatidylcholine, PC） to be used as substitute for hen egg yolk in extender for preserving goat semen...The objective of the present study was to determine the proper sources and concentrations of soybean lecithin （phosphatidylcholine, PC） to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin （20% and 95% soybean phosphatidylcholine; PC20 and PC95） and three concentrations （1%, 2% and 3% v/v） of PC20 and PC95 supplemented in Tris-citric acid-fructose （TCF） extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ （equilibration）. The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender （P 〈 0.05）. Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders （P 〈 0.05）. PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 （P 〈 0.05）. It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% （v/v） is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs .展开更多
This paper discusses a preferable solution to mitigate the CT （current transformer） saturation problem, and at same time, reduce the accuracy errors when considering the selection of CTs for installation on the medi...This paper discusses a preferable solution to mitigate the CT （current transformer） saturation problem, and at same time, reduce the accuracy errors when considering the selection of CTs for installation on the medium voltage switchgear of a nuclear power plant. This consideration is important for both measurement and protection functions of the digital protective relays. This is a study to ascertain the best options for a suitable solution to prevent CT saturation in relations to its protective capabilities during short circuit fault without compromising the CT accuracy class during normal operation of the system, while ensuring its conformity to the design requirement is within limit. The advantages of current transformers have proven not only to be reliable and safe, but also are of easy handling, reduction of the cost and components on the MV （medium voltage） switchgear. The purpose of this research is to identify best approach to resolve the existing problems in the current protection system. With the view of LPCT （low power current transformer） which has been newly constructed by few manufacturers to provide good protection and a wide range of measuring function without errors, some other solutions will be considered in this research.展开更多
In this paper, we derive an upper bound for the adiabatic approximation error, which is the distance between the exact solution to a Schrodinger equation and the adiabatic approximation solution. As an application, we...In this paper, we derive an upper bound for the adiabatic approximation error, which is the distance between the exact solution to a Schrodinger equation and the adiabatic approximation solution. As an application, we obtain an upper bound for 1 minus the fidelity of the exact solution and the adiabatic approximation solution to a SchrOdinger equation.展开更多
基金Supported by Hebei Handan Key Research Subject(2011-33)
文摘[Objective] The aim was to study the aromas composition of plum fruit. [Method] The aroma components of six kinds of plum fruits were analyzed by SPME, detected and identified by GC-MS.[Result] 85 kinds of aroma substances were separated and identified, including 40 kinds of common components.The experiments had good reproducibility by strictly controlling the desorption temperature, time and sample holding time.The obtained chromatographic peak retention time and the normalized area variation coefficient CV% values were between 0.03% -0.54% and 5.85% -18.08% by experimenting the five precision of AoLi13.The qualitative and quantitative were fully meet repeatability requirements for test samples. [Conclusion] The study provided scientific basis for the development and process of plum industry in China.
文摘This paper presents a new method of improving Global Positioning System(GPS)positioning precision. Based on the altitude hold mode, the method does not need any other equipment. Under this constraint condition, the Total Least Squares(TLS) algorithm is used to prove that the method is effective. Theoretical analysis shows that the algorithm can significantly improve the GPS positioning precision.
文摘The objective of the present study was to determine the proper sources and concentrations of soybean lecithin （phosphatidylcholine, PC） to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin （20% and 95% soybean phosphatidylcholine; PC20 and PC95） and three concentrations （1%, 2% and 3% v/v） of PC20 and PC95 supplemented in Tris-citric acid-fructose （TCF） extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ （equilibration）. The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender （P 〈 0.05）. Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders （P 〈 0.05）. PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 （P 〈 0.05）. It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% （v/v） is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs .
文摘This paper discusses a preferable solution to mitigate the CT （current transformer） saturation problem, and at same time, reduce the accuracy errors when considering the selection of CTs for installation on the medium voltage switchgear of a nuclear power plant. This consideration is important for both measurement and protection functions of the digital protective relays. This is a study to ascertain the best options for a suitable solution to prevent CT saturation in relations to its protective capabilities during short circuit fault without compromising the CT accuracy class during normal operation of the system, while ensuring its conformity to the design requirement is within limit. The advantages of current transformers have proven not only to be reliable and safe, but also are of easy handling, reduction of the cost and components on the MV （medium voltage） switchgear. The purpose of this research is to identify best approach to resolve the existing problems in the current protection system. With the view of LPCT （low power current transformer） which has been newly constructed by few manufacturers to provide good protection and a wide range of measuring function without errors, some other solutions will be considered in this research.
基金supported by the National Natural Science Fundation of China(Grant No.11171197)the Fundamental Research Funds for the Central Universities(Grant No.GK201301007)the Innovation Fund Project for Graduate Program of Shaanxi Normal University(Grant No.2013CXB012)
文摘In this paper, we derive an upper bound for the adiabatic approximation error, which is the distance between the exact solution to a Schrodinger equation and the adiabatic approximation solution. As an application, we obtain an upper bound for 1 minus the fidelity of the exact solution and the adiabatic approximation solution to a SchrOdinger equation.
