Calculations of secondary electron yield（SEY） by physical formula can hardly accord with experimental results precisely. Simplified descriptions of internal electron movements in the calculation and complex surface ...Calculations of secondary electron yield（SEY） by physical formula can hardly accord with experimental results precisely. Simplified descriptions of internal electron movements in the calculation and complex surface contamination states of real sample result in notable difference between simulations and experiments. In this paper, in order to calculate SEY of metal under complicated surface state accurately, we propose a synthetic semi-empirical physical model. The processes of excitation of internal secondary electron（SE） and movement toward surface can be simulated using this model.This model also takes into account the influences of incident angle and backscattering electrons as well as the surface gas contamination. In order to describe internal electronic states accurately, the penetration coefficient of incident electron is described as a function of material atom number. Directions of internal electrons are set to be uniform in each angle. The distribution of internal SEs is proposed by considering both the integration convergence and the cascade scattering process.In addition, according to the experiment data, relationship among desorption gas quantities, sample ultimate temperature and SEY is established. Comparing with experiment results, this synthetic semi-empirical physical model can describe the SEY of metal better than former formulas, especially in the aspect of surface contaminated states. The proposed synthetic semi-empirical physical model and presented results in this paper can be helpful for further studying SE emission, and offer an available method for estimating and taking advantage of SE emission accurately.展开更多
A synthetic polypeptide, pt27, which is encoded by a cDNA clone with antloncogene activity, p14-6, is found to be able to reduce remarkably the soft agar colony formation ability of part of DT cells and to raise their...A synthetic polypeptide, pt27, which is encoded by a cDNA clone with antloncogene activity, p14-6, is found to be able to reduce remarkably the soft agar colony formation ability of part of DT cells and to raise their resistance to the ouabaln toxtcity. This shows that the pt27 peptide can affect the DT cells In a manner similar to the p14- 6 done and provides evidence that the reverting action of the p14-6 to DT cells may be exerted by the expression of its cDNA.展开更多
Based on semi - order fuzzy supermaringales andsubmartingales, the semi- order fuzzy supermartingaleand submartingale theory is developed. The main resultis to generalize the Doob decomposition and the Riesz de-compos...Based on semi - order fuzzy supermaringales andsubmartingales, the semi- order fuzzy supermartingaleand submartingale theory is developed. The main resultis to generalize the Doob decomposition and the Riesz de-composition theorems of standard martingale theory tosemi - order fuzzy supermaringales and submartingales.The structure of semi - order fuzzy supermaringales andsubmartingales and the conditions of that they has Doobdecomposition (resp. Riesz decomposition) are discussedin detail.展开更多
This paper reviewed all types of the polymer - based synthetic absorbable surgical sutures that have been commercially produced. The chemical component, biological and mechanical properties, and using effect of these ...This paper reviewed all types of the polymer - based synthetic absorbable surgical sutures that have been commercially produced. The chemical component, biological and mechanical properties, and using effect of these sutures were discussed. The recent development and the possible coming research orientation in these areas were also presented.展开更多
针对合成孔径雷达(synthetic aperture radar,SAR)图像变化检测获得有标记样本的数量十分有限且困难,传统方法检测率低等问题,提出了一种基于原始特征空间的K均值和支持向量机(K-means and support vector machine,KM-SVM)法SAR图像无...针对合成孔径雷达(synthetic aperture radar,SAR)图像变化检测获得有标记样本的数量十分有限且困难,传统方法检测率低等问题,提出了一种基于原始特征空间的K均值和支持向量机(K-means and support vector machine,KM-SVM)法SAR图像无监督变化检测。首先,不需要任何先验信息的条件下,利用K-means聚类方法获取差异图像的分类阈值;其次,利用阈值,引入偏移量,自动选取伪训练集和无标签集,并用伪训练集定义SVM的初始决策超平面;最后,用基于统计特征的半监督学习算法和支持向量机相结合对图像进行变化类与非变化类的分类。实验结果表明:该算法优于基于混合高斯分布模型的KI法和基于广义高斯分布模型的KI法,能保持较好的分类、泛化能力和较稳定的检测精度。这些结果表明了文中方法的有效性。展开更多
本文论述了用于极高可靠性供电要求的场合如芯片工厂的配电架构改良,单独内燃机驱动的柴油发电机组(下文简称柴发)作为后备电源进行供电保障优化为结合储能以及不间断电源(Uninterrupted Power Supply,下文简称UPS)相组合的供电保障,UP...本文论述了用于极高可靠性供电要求的场合如芯片工厂的配电架构改良,单独内燃机驱动的柴油发电机组(下文简称柴发)作为后备电源进行供电保障优化为结合储能以及不间断电源(Uninterrupted Power Supply,下文简称UPS)相组合的供电保障,UPS的接线拓扑分析以及采用预充磁装置对优化的拓扑进行进一步改良。展开更多
Aldo-keto reductase 1D1(AKR1D1) deficiency,a rare but life-threatening form of bile acid deficiency,has not been previously described in China.Here,we describe the first two primary 4-3-oxosteroid 5β-reductase defici...Aldo-keto reductase 1D1(AKR1D1) deficiency,a rare but life-threatening form of bile acid deficiency,has not been previously described in China.Here,we describe the first two primary 4-3-oxosteroid 5β-reductase deficiency patients in China's Mainland diagnosed by fast atom bombardment-mass spectroscopy of urinary bile acids and confirmed by genetic analysis.A high proportion of atypical 3-oxo-4-bile acids in the urine indicated a deficiency in 4-3-oxosteroid 5β-reductase.All of the coding exons and adjacent intronic sequence of the AKR1D1 gene were sequenced using peripheral lymphocyte genomic DNA of two patients and one of the patient's parents.One patient exhibited compound heterozygous mutations:c.396C>A and c.722A>T,while the other was heterozygous for the mutation c.797G>A.Based on these mutations,a diagnosis of primary 4-3-oxosteroid 5β-reductase deficiency could be confirmed.With ursodeoxycholic acid treatment and fat-soluble vitamin supplements,liver function tests normalized rapidly,and the degree of hepatomegaly was markedly reduced in both patients.展开更多
Optimization of antenna array pattern used in a spaceborne Synthetic Aperture Radar (SAR) system is considered in this study. A robust evolutionary algorithm, Non-dominated Sorting Genetic Algorithms (the improved NS...Optimization of antenna array pattern used in a spaceborne Synthetic Aperture Radar (SAR) system is considered in this study. A robust evolutionary algorithm, Non-dominated Sorting Genetic Algorithms (the improved NSGA-Ⅱ), is applied on a spaceborne SAR antenna pattern design. The system consists of two objective functions with two constraints. Pareto fronts are generated as a result of multi-objective optimization. After being validated by a test problem ZDT4, the algorithms are used to synthesize spaceborne SAR antenna radiation pattern. The good results with low Ambi- guity-to-Signal Ratio (ASR) and high directivity are obtained in the paper.展开更多
A global cross-section of the Earth parallel to the tectonic equator（TE） path,the great circle representing the equator of net lithosphere rotation,shows a difference in shear wave velocities between the western and...A global cross-section of the Earth parallel to the tectonic equator（TE） path,the great circle representing the equator of net lithosphere rotation,shows a difference in shear wave velocities between the western and eastern flanks of the three major oceanic rift basins.The lowvelocity layer in the upper asthenosphere,at a depth range of 120 to 200 km,is assumed to represent the decoupling between the lithosphere and the underlying mantle.Along the TE-perturbed（TE-pert） path,a ubiquitous LVZ,about 1,000-km-wide and 100-km-thick,occurs in the asthenosphere.The existence of the TE-pert is a necessary prerequisite for the existence of a continuous global flow within the Earth.Ground-shaking scenarios were constructed using a scenario-based method for seismic hazard analysis（NDSHA）,using realistic and duly validated synthetic time series,and generating a data bank of several thousands of seismograms that account for source,propagation,and site effects.Accordingly,with basic selforganized criticality concepts,NDSHA permits the integration of available information provided by the most updated seismological,geological,geophysical,and geotechnical databases for the site of interest,as well as advanced physical modeling techniques,to provide a reliable and robust background for the development of a design basis for cultural heritage and civil infrastructures.Estimates of seismic hazard obtained using the NDSHA and standard probabilistic approaches are compared for the Italian territory,and a case-study is discussed.In order to enable a reliable estimation of the ground motion response to an earthquake,three-dimensional velocity models have to be considered,resulting in a new,very efficient,analytical procedure for computing the broadband seismic wave-field in a 3-D anelastic Earth model.展开更多
The synthesis of 1,3,5-substituted-1,2,4-triazoles from α-imino-3-pyridine formic acid,acetamidine and anisole hydrazine as a model reaction in this paper and the synthesis mechanism of 1,3,5-substituted-1,2,4-triazo...The synthesis of 1,3,5-substituted-1,2,4-triazoles from α-imino-3-pyridine formic acid,acetamidine and anisole hydrazine as a model reaction in this paper and the synthesis mechanism of 1,3,5-substituted-1,2,4-triazole compounds from carboxylic acids,amidines and hydrazines have been first investigated with the B3 LYP/6-311＋＋G＊＊ method.According to the potential energy profile,it can be predicted that the course of the reaction consists of five reactions containing six elementary reactions.The α-imino-3-pyridine formic acid and acetamidine form first an intermediate product through a dehydration reaction; the intermediate product further combines with hydrogen ion to form a positive ion; the positive ion reacts with anisole hydrazine by a dehydration reaction to form another positive ion; then,followed by two isomerization reactions,the final reaction with the acetate ion（Ac-） produces the final product.The research results reveal the laws of synthesis reaction of 1,3,5-substituted-1,2,4-triazoles by the carboxylic acids,amidines,hydrazines and their derivatives on theoretical level.It provides the systemic theoretical basis for the synthesis,development and application of 1,3,5-substituted-1,2,4-triazole compounds.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1537211 and 11675278)the China Postdoctoral Science Foundation(Grant No.2016M602944XB)
文摘Calculations of secondary electron yield（SEY） by physical formula can hardly accord with experimental results precisely. Simplified descriptions of internal electron movements in the calculation and complex surface contamination states of real sample result in notable difference between simulations and experiments. In this paper, in order to calculate SEY of metal under complicated surface state accurately, we propose a synthetic semi-empirical physical model. The processes of excitation of internal secondary electron（SE） and movement toward surface can be simulated using this model.This model also takes into account the influences of incident angle and backscattering electrons as well as the surface gas contamination. In order to describe internal electronic states accurately, the penetration coefficient of incident electron is described as a function of material atom number. Directions of internal electrons are set to be uniform in each angle. The distribution of internal SEs is proposed by considering both the integration convergence and the cascade scattering process.In addition, according to the experiment data, relationship among desorption gas quantities, sample ultimate temperature and SEY is established. Comparing with experiment results, this synthetic semi-empirical physical model can describe the SEY of metal better than former formulas, especially in the aspect of surface contaminated states. The proposed synthetic semi-empirical physical model and presented results in this paper can be helpful for further studying SE emission, and offer an available method for estimating and taking advantage of SE emission accurately.
文摘A synthetic polypeptide, pt27, which is encoded by a cDNA clone with antloncogene activity, p14-6, is found to be able to reduce remarkably the soft agar colony formation ability of part of DT cells and to raise their resistance to the ouabaln toxtcity. This shows that the pt27 peptide can affect the DT cells In a manner similar to the p14- 6 done and provides evidence that the reverting action of the p14-6 to DT cells may be exerted by the expression of its cDNA.
文摘Based on semi - order fuzzy supermaringales andsubmartingales, the semi- order fuzzy supermartingaleand submartingale theory is developed. The main resultis to generalize the Doob decomposition and the Riesz de-composition theorems of standard martingale theory tosemi - order fuzzy supermaringales and submartingales.The structure of semi - order fuzzy supermaringales andsubmartingales and the conditions of that they has Doobdecomposition (resp. Riesz decomposition) are discussedin detail.
文摘This paper reviewed all types of the polymer - based synthetic absorbable surgical sutures that have been commercially produced. The chemical component, biological and mechanical properties, and using effect of these sutures were discussed. The recent development and the possible coming research orientation in these areas were also presented.
文摘针对合成孔径雷达(synthetic aperture radar,SAR)图像变化检测获得有标记样本的数量十分有限且困难,传统方法检测率低等问题,提出了一种基于原始特征空间的K均值和支持向量机(K-means and support vector machine,KM-SVM)法SAR图像无监督变化检测。首先,不需要任何先验信息的条件下,利用K-means聚类方法获取差异图像的分类阈值;其次,利用阈值,引入偏移量,自动选取伪训练集和无标签集,并用伪训练集定义SVM的初始决策超平面;最后,用基于统计特征的半监督学习算法和支持向量机相结合对图像进行变化类与非变化类的分类。实验结果表明:该算法优于基于混合高斯分布模型的KI法和基于广义高斯分布模型的KI法,能保持较好的分类、泛化能力和较稳定的检测精度。这些结果表明了文中方法的有效性。
文摘本文论述了用于极高可靠性供电要求的场合如芯片工厂的配电架构改良,单独内燃机驱动的柴油发电机组(下文简称柴发)作为后备电源进行供电保障优化为结合储能以及不间断电源(Uninterrupted Power Supply,下文简称UPS)相组合的供电保障,UPS的接线拓扑分析以及采用预充磁装置对优化的拓扑进行进一步改良。
基金Supported by National Natural Science Foundation of China, No.81070281
文摘Aldo-keto reductase 1D1(AKR1D1) deficiency,a rare but life-threatening form of bile acid deficiency,has not been previously described in China.Here,we describe the first two primary 4-3-oxosteroid 5β-reductase deficiency patients in China's Mainland diagnosed by fast atom bombardment-mass spectroscopy of urinary bile acids and confirmed by genetic analysis.A high proportion of atypical 3-oxo-4-bile acids in the urine indicated a deficiency in 4-3-oxosteroid 5β-reductase.All of the coding exons and adjacent intronic sequence of the AKR1D1 gene were sequenced using peripheral lymphocyte genomic DNA of two patients and one of the patient's parents.One patient exhibited compound heterozygous mutations:c.396C>A and c.722A>T,while the other was heterozygous for the mutation c.797G>A.Based on these mutations,a diagnosis of primary 4-3-oxosteroid 5β-reductase deficiency could be confirmed.With ursodeoxycholic acid treatment and fat-soluble vitamin supplements,liver function tests normalized rapidly,and the degree of hepatomegaly was markedly reduced in both patients.
文摘Optimization of antenna array pattern used in a spaceborne Synthetic Aperture Radar (SAR) system is considered in this study. A robust evolutionary algorithm, Non-dominated Sorting Genetic Algorithms (the improved NSGA-Ⅱ), is applied on a spaceborne SAR antenna pattern design. The system consists of two objective functions with two constraints. Pareto fronts are generated as a result of multi-objective optimization. After being validated by a test problem ZDT4, the algorithms are used to synthesize spaceborne SAR antenna radiation pattern. The good results with low Ambi- guity-to-Signal Ratio (ASR) and high directivity are obtained in the paper.
文摘A global cross-section of the Earth parallel to the tectonic equator（TE） path,the great circle representing the equator of net lithosphere rotation,shows a difference in shear wave velocities between the western and eastern flanks of the three major oceanic rift basins.The lowvelocity layer in the upper asthenosphere,at a depth range of 120 to 200 km,is assumed to represent the decoupling between the lithosphere and the underlying mantle.Along the TE-perturbed（TE-pert） path,a ubiquitous LVZ,about 1,000-km-wide and 100-km-thick,occurs in the asthenosphere.The existence of the TE-pert is a necessary prerequisite for the existence of a continuous global flow within the Earth.Ground-shaking scenarios were constructed using a scenario-based method for seismic hazard analysis（NDSHA）,using realistic and duly validated synthetic time series,and generating a data bank of several thousands of seismograms that account for source,propagation,and site effects.Accordingly,with basic selforganized criticality concepts,NDSHA permits the integration of available information provided by the most updated seismological,geological,geophysical,and geotechnical databases for the site of interest,as well as advanced physical modeling techniques,to provide a reliable and robust background for the development of a design basis for cultural heritage and civil infrastructures.Estimates of seismic hazard obtained using the NDSHA and standard probabilistic approaches are compared for the Italian territory,and a case-study is discussed.In order to enable a reliable estimation of the ground motion response to an earthquake,three-dimensional velocity models have to be considered,resulting in a new,very efficient,analytical procedure for computing the broadband seismic wave-field in a 3-D anelastic Earth model.
基金supported by the National Natural Science Foundation of China(No.51102114)
文摘The synthesis of 1,3,5-substituted-1,2,4-triazoles from α-imino-3-pyridine formic acid,acetamidine and anisole hydrazine as a model reaction in this paper and the synthesis mechanism of 1,3,5-substituted-1,2,4-triazole compounds from carboxylic acids,amidines and hydrazines have been first investigated with the B3 LYP/6-311＋＋G＊＊ method.According to the potential energy profile,it can be predicted that the course of the reaction consists of five reactions containing six elementary reactions.The α-imino-3-pyridine formic acid and acetamidine form first an intermediate product through a dehydration reaction; the intermediate product further combines with hydrogen ion to form a positive ion; the positive ion reacts with anisole hydrazine by a dehydration reaction to form another positive ion; then,followed by two isomerization reactions,the final reaction with the acetate ion（Ac-） produces the final product.The research results reveal the laws of synthesis reaction of 1,3,5-substituted-1,2,4-triazoles by the carboxylic acids,amidines,hydrazines and their derivatives on theoretical level.It provides the systemic theoretical basis for the synthesis,development and application of 1,3,5-substituted-1,2,4-triazole compounds.
