The ion thruster is an engine with high specific impulse for satellites and spacecrafts,which uses electric energy to boost the spacecraft.The ion optical system,also known as gate assemblies which consist of accelera...The ion thruster is an engine with high specific impulse for satellites and spacecrafts,which uses electric energy to boost the spacecraft.The ion optical system,also known as gate assemblies which consist of acceleration and screen grids,is the key component of the ion thruster.In this paper,the static mechanical properties of the C/C composite grids are evaluated based on the structural design.Representative volume element (RVE) is adopted to simplify the braded composite structure as a continuum material.The dynamical behavior of the 100 mm ion thruster optics in the launch environment (1000g shock-load) is numerically modeled and simulated with the half-sine pulse method.The impact response of the C/C and molybdenum gate assemblies on the stress distribution and deformation is investigated.The simulated results indicate that the magnitudes of the normal displacement of the composite grids subject to the uniformly distributed load are on the same level as molybdenum grids although the normal stiffness of the composite grids is much smaller.When subject to impact loading,the stress distribution in the C/C composite grids is similar to molybdenum grids while the stress magnitude is much smaller.This finding shows that the C/C gate assemblies outperform molybdenum grids and meet the requirement of long lifetime service in space travel.展开更多
Objective: To study the distribution of c fos oncogene expression within central nervous system (CNS) of the rat during halothane anesthesia. Methods: c-fos oncogene immunohistochemical technique (ABC method) was empl...Objective: To study the distribution of c fos oncogene expression within central nervous system (CNS) of the rat during halothane anesthesia. Methods: c-fos oncogene immunohistochemical technique (ABC method) was employed. Results: When halothane concentration was 0.75%,1.5%or2.0%, most of the Fos-like immunore- active neurons (FLNs) appeared in telencephalon, diencephalon and brain stem, including cerebral cortex, amygaloid nucleus, accumbens nucleus, lateral keptal nucleus. bed nucleus of the stria terminalis, field CA1 of Ammon’s horn, islands of Calleja, paraventricular thalamic nucleus, central medial thalamic nucleus, reuniens thalamic nucleus, rhomboid thalamic nucleus. ventral posterolateral thalamic nucleus, paraventricular hypothalamic nucleus(ventral part). periventricular hypothalamic nucleus, median preoptic nucleus, supraoptic nucleus, suprachiasmatic nucleus. medial and lateral habenular nucleus. midbrain periaqueductal gray and Edinger-Westphal nucleus.In the present stude. we have also found that the number of FLN registered stable increase along with the increaseof the concentration of halothane. Conclusion: It has been indicated that FLNs participate in the process ofhalothane anesthesia. which should necessitate and pave the way for a further study of the patterns of linkage andthe mechanism of interaction between functional nuclei.展开更多
Objective To investigate the biological function of NS5ABP37 and to look for proteins interacting with NS5ABP37 protein in hepatocytes.Methods We constructed bait plasmid expressing NS5ABP37 protein of hepatitis C vir...Objective To investigate the biological function of NS5ABP37 and to look for proteins interacting with NS5ABP37 protein in hepatocytes.Methods We constructed bait plasmid expressing NS5ABP37 protein of hepatitis C virus(HCV)by cloning the gene of NS5ABP37 protein into pGBKT7,then the recombinant plasmid DNA was transformed into yeast AH109(α type).The transformed yeast AH109 was mated with yeast Y187(α type)containing liver cDNA library plasmid in 2×YPDA medium.Diploid yeast was plated on synthetic dropout nutrient medium(SD/-Trp-Leu-His-Ade)containing X-α-gal for selection and screening.After extracting and sequencing of plasmids from positive(blue)colonies,we made a sequence analysis by bioinformatics.Results We screened twenty-five proteins binding to NS5ABP37,including Homo sapiens cyclin I(CCNI)gene,Homo sapiens matrix metallopeptidase 25(MMP25)and Homo sapiens talin 1.Conclusion The yeast-two hybrid system is an effective method for identifying hepatocyte proteins interacting with NS5ABP37 of HCV.And the biological function of NS5ABP37 may be associated with glycometabolism,lipid metabolism and apoptosis.展开更多
The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determi...The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the inlfuences of various tillage systems on soil aggregation and aggregate-associated C under wheat （Triticum aestivum L.） and corn （Zea mays L.） double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments：moldboard plow （MP） with residue （MP＋R） and without residue （MP-R）, rotary tillage with residue （RT）, and no-till with residue （NT）. In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes （〉2 000, 250-2 000, 53-250, and〈53 μm） by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments signiifcantly increased the proportion of macroaggregate fractions （〉2 000 and 250-2 000 μm） compared with the MP-R and MP＋R treatments. Averaged across all depths, mean weight diameters of aggregates （MWD） in NT and RT were 47 and 20% higher than that in MP＋R. The concentration of bulk soil organic C was positively correlated with MWD （r=0.98; P=0.024） and macroaggregate fraction （r=0.96; P=0.036） in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP＋R, total C occluded in the〉2 000 μm fraction was increased by 9 and 6%under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain.展开更多
Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe t...Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe the causal relationships among the decision objective and the variables of the scheduling process for the industrial system, based on which the total scheduling amount of the BFG system can be computed by using a causal fuzzy C-means(CFCM) clustering algorithm. In this algorithm,not only the distances among the historical samples but also the effects of different solutions on the gas tank level are considered.The scheduling solution can be determined based on the proposed causal probability of the causality diagram calculated by the total amount and the conditions of the adjustable units. The causal probability quantifies the impact of different allocation schemes of the total scheduling amount on the BFG system. An evaluation method is then proposed to evaluate the effectiveness of the scheduling solutions. The experiments by using the practical data coming from a steel plant in China indicate that the proposed approach can effectively improve the scheduling accuracy and reduce the gas diffusion.展开更多
The whole airspace phased array telemetry,track and command(TT&C)system is regarded as the development tendency of next generation TT&C system,and the distribution of the antenna units and the beamforming tech...The whole airspace phased array telemetry,track and command(TT&C)system is regarded as the development tendency of next generation TT&C system,and the distribution of the antenna units and the beamforming technology have sparked wide interest in this field.A method for antenna distribution is proposed based on the linear subarrays technology.A symmetrical truncated cone conformal array is composed of the linear subarrays placed on the generatrix.The impact of truncated cone bottom radius and elevation angle on beamforming are studied and simulated.Simulation results verify the system design.展开更多
基金Project supported by the National Key R&D Program of China(No.2018YFF01014200)the National Natural Science Foundation of China(Nos.11727804,11672347,and 51732008)
文摘The ion thruster is an engine with high specific impulse for satellites and spacecrafts,which uses electric energy to boost the spacecraft.The ion optical system,also known as gate assemblies which consist of acceleration and screen grids,is the key component of the ion thruster.In this paper,the static mechanical properties of the C/C composite grids are evaluated based on the structural design.Representative volume element (RVE) is adopted to simplify the braded composite structure as a continuum material.The dynamical behavior of the 100 mm ion thruster optics in the launch environment (1000g shock-load) is numerically modeled and simulated with the half-sine pulse method.The impact response of the C/C and molybdenum gate assemblies on the stress distribution and deformation is investigated.The simulated results indicate that the magnitudes of the normal displacement of the composite grids subject to the uniformly distributed load are on the same level as molybdenum grids although the normal stiffness of the composite grids is much smaller.When subject to impact loading,the stress distribution in the C/C composite grids is similar to molybdenum grids while the stress magnitude is much smaller.This finding shows that the C/C gate assemblies outperform molybdenum grids and meet the requirement of long lifetime service in space travel.
文摘Objective: To study the distribution of c fos oncogene expression within central nervous system (CNS) of the rat during halothane anesthesia. Methods: c-fos oncogene immunohistochemical technique (ABC method) was employed. Results: When halothane concentration was 0.75%,1.5%or2.0%, most of the Fos-like immunore- active neurons (FLNs) appeared in telencephalon, diencephalon and brain stem, including cerebral cortex, amygaloid nucleus, accumbens nucleus, lateral keptal nucleus. bed nucleus of the stria terminalis, field CA1 of Ammon’s horn, islands of Calleja, paraventricular thalamic nucleus, central medial thalamic nucleus, reuniens thalamic nucleus, rhomboid thalamic nucleus. ventral posterolateral thalamic nucleus, paraventricular hypothalamic nucleus(ventral part). periventricular hypothalamic nucleus, median preoptic nucleus, supraoptic nucleus, suprachiasmatic nucleus. medial and lateral habenular nucleus. midbrain periaqueductal gray and Edinger-Westphal nucleus.In the present stude. we have also found that the number of FLN registered stable increase along with the increaseof the concentration of halothane. Conclusion: It has been indicated that FLNs participate in the process ofhalothane anesthesia. which should necessitate and pave the way for a further study of the patterns of linkage andthe mechanism of interaction between functional nuclei.
文摘Objective To investigate the biological function of NS5ABP37 and to look for proteins interacting with NS5ABP37 protein in hepatocytes.Methods We constructed bait plasmid expressing NS5ABP37 protein of hepatitis C virus(HCV)by cloning the gene of NS5ABP37 protein into pGBKT7,then the recombinant plasmid DNA was transformed into yeast AH109(α type).The transformed yeast AH109 was mated with yeast Y187(α type)containing liver cDNA library plasmid in 2×YPDA medium.Diploid yeast was plated on synthetic dropout nutrient medium(SD/-Trp-Leu-His-Ade)containing X-α-gal for selection and screening.After extracting and sequencing of plasmids from positive(blue)colonies,we made a sequence analysis by bioinformatics.Results We screened twenty-five proteins binding to NS5ABP37,including Homo sapiens cyclin I(CCNI)gene,Homo sapiens matrix metallopeptidase 25(MMP25)and Homo sapiens talin 1.Conclusion The yeast-two hybrid system is an effective method for identifying hepatocyte proteins interacting with NS5ABP37 of HCV.And the biological function of NS5ABP37 may be associated with glycometabolism,lipid metabolism and apoptosis.
基金funded by the National Natural Science Foundation of China(31000250)the National 973 Program of China(2009CB118607)
文摘The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the inlfuences of various tillage systems on soil aggregation and aggregate-associated C under wheat （Triticum aestivum L.） and corn （Zea mays L.） double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments：moldboard plow （MP） with residue （MP＋R） and without residue （MP-R）, rotary tillage with residue （RT）, and no-till with residue （NT）. In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes （〉2 000, 250-2 000, 53-250, and〈53 μm） by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments signiifcantly increased the proportion of macroaggregate fractions （〉2 000 and 250-2 000 μm） compared with the MP-R and MP＋R treatments. Averaged across all depths, mean weight diameters of aggregates （MWD） in NT and RT were 47 and 20% higher than that in MP＋R. The concentration of bulk soil organic C was positively correlated with MWD （r=0.98; P=0.024） and macroaggregate fraction （r=0.96; P=0.036） in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP＋R, total C occluded in the〉2 000 μm fraction was increased by 9 and 6%under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain.
基金supported by the National Natural Sciences Foundation of China(61473056,61533005,61522304,61603068,U1560102)
文摘Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe the causal relationships among the decision objective and the variables of the scheduling process for the industrial system, based on which the total scheduling amount of the BFG system can be computed by using a causal fuzzy C-means(CFCM) clustering algorithm. In this algorithm,not only the distances among the historical samples but also the effects of different solutions on the gas tank level are considered.The scheduling solution can be determined based on the proposed causal probability of the causality diagram calculated by the total amount and the conditions of the adjustable units. The causal probability quantifies the impact of different allocation schemes of the total scheduling amount on the BFG system. An evaluation method is then proposed to evaluate the effectiveness of the scheduling solutions. The experiments by using the practical data coming from a steel plant in China indicate that the proposed approach can effectively improve the scheduling accuracy and reduce the gas diffusion.
文摘The whole airspace phased array telemetry,track and command(TT&C)system is regarded as the development tendency of next generation TT&C system,and the distribution of the antenna units and the beamforming technology have sparked wide interest in this field.A method for antenna distribution is proposed based on the linear subarrays technology.A symmetrical truncated cone conformal array is composed of the linear subarrays placed on the generatrix.The impact of truncated cone bottom radius and elevation angle on beamforming are studied and simulated.Simulation results verify the system design.
