检索结果-南通市图书馆

Latest progress on interactions between VLF/ELF waves and energetic electrons in the inner magnetosphere

Science china Earth Sciences 2010年第3期53卷 317-326页

作者： XIAO FuLiang1,2, ZONG QiuGang3, SU ZhenPeng4, TIAN Tian3 & ZHENG HuiNan4 1 School of physics and Electronic Sciences, Changsha university of Science and technology, Changsha 410004, china 2 State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190, china 3 Institute of Space physics and Applied technology, Peking university, Beijing 100871, china 4 CAS Key Lab for Basic Plasma Science, School of Earth and Space Sciences, university of Science and technology of china, Hefei 230026, china School of physics and Electronic Sciences Changsha University of Science and Technology Changsha China State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing China Institute of Space physics and Applied technology Peking University Beijing China CAS Key Lab for Basic Plasma Science School of Earth and Space Sciences University of Science and Technology of China Hefei China

Interactions between very/extremely low frequency (VLF/ELF) waves and energetic electrons play a fundamental role in dynamics occurring in the inner magnetosphere. Here, we briefly discuss global properties of VLF/ELF waves, along with the variability of the electron radiation belts associated with wave-particle interactions and radial diffusion. We provide cases of electron loss and acceleration as a result of wave-particle interactions primarily due to such waves, and particularly some preliminary results of 3D evolution of phase space density from our currently developing 3D code. We comment on the existing mechanisms responsible for acceleration and loss, and identify several critical issues that need to be addressed. We review latest progress and suggest open questions for future investigation.

关键词： wave-particle interaction VLF/ELF waves energetic electrons acceleration and loss inner magnetosphere

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于机器学习的二维流体VOF方法

引用

中国造船 2024年第3期65卷 244-253页

作者：孟巍梅桂林哈尔滨工程大学船舶工程学院哈尔滨150001

以网格顶点和网格中心的流体体积分数为输入,利用深度学习神经网络(DNN)进行两相界面的快速几何重构,改进了一种几何VOF方法——isoAdvector算法。在原始isoAdvector算法生成训练集并进行预处理的基础上,通过神经网络隐藏层中神经元个... 详细信息

以网格顶点和网格中心的流体体积分数为输入,利用深度学习神经网络(DNN)进行两相界面的快速几何重构,改进了一种几何VOF方法——isoAdvector算法。在原始isoAdvector算法生成训练集并进行预处理的基础上,通过神经网络隐藏层中神经元个数和激活函数对预测结果的影响来确定适当的神经网络;并根据质量守恒修正神经网络预测结果,完成两相界面的几何重构。在OpenFOAM框架下,嵌入神经网络修正改进后的isoAdvector算法。二维溃坝数值模拟结果表明:改进算法与原始算法计算精度相当,计算效率有所提升。

关键词：自由液面捕捉几何VOF方法深度神经网络 isoAdvector算法 OpenFOAM

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On a problem of Skiba from the Kourovka Notebook

引用

Science china Mathematics 2004年第1期47卷 96-103页

作者： WANG Yanming & WEI HuaquanLingnan college and School of Mathematics, Zhongshan university, Guangzhou 510275, china School of Mathematics, Zhongshan university, Guangzhou 510275, china Department of Mathematics, guangxi Teacher’s college, Nanning 530001, china Lingnan college and School of Mathematics Zhongshan University Guangzhou China School of Mathematics Zhongshan University Guangzhou China Department of Mathematics Guangxi Teacher’s College Nanning China

In this paper, we give a positive answer to a recent open problem of Skiba in Kourovka Notebook without using the odd order theorem and other deep theorems. Some of the techniques are improved.

关键词： supersolvable group c-supple merited subgroup complemented subgroup generalized fitting subgroup saturated formation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical study on behaviors of 1s^22s-1s^2np transition for Co^(24+) ion in the whole energy region

引用

Science china(physics,Mechanics & Astronomy) 2009年第12期52卷 1971-1975页

作者： WANG ZhiWen,TONG BaiChun,HU MuHong,GUO Yang & LI Ye college of physics and Electronic technology,Liaoning Normal university,Dalian 116029,china college of physics and Electronic technology Liaoning Normal University Dalian China

Non-relativistic energies of 1s22s and 1s2np (n≤9) states for Co24+ ion are calculated by using the full-core plus correlation method. Our results of 1s22s and 1s22p states agree well with the high-precision results of Yan et al. Based on calculating the first-order corrections to the energy from relativistic and mass-polarization effects,we estimate the higher-order relativistic contribution and QED correc-tion to the energy under a hydrogenic approximation. The transition energies,wavelengths and oscil-lator strengths for the 1s22s-1s2np (n≤9) transitions of this ion are calculated. The results agree with the experimental data available in literature satisfactorily. By combining with quantum defect theory,our theoretical predictions on the energy and oscillator strength of this ion are extrapolated to the whole energy region including continuous states.

关键词： Co24+ ion transition energy wavelength oscillator strength quantum defect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Correlation between pulse-width and peak luminosity of single-pulse long gamma-ray bursts

引用

Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 69-72页

作者： DENG JiaGan & LIANG EnWei Department of physics,guangxi university,Nanning 530004,china Department of physics Guangxi University Nanning China

With a sample of 21 single-pulse GRBs with redshift measurement and a sample of 65 single-pulse GRBs with pseudo redshift estimated by the luminosity-spectral lag relation,we show that the peak luminosities of GRB pulses are anti-correlated with pulse width,indicating that longer-pulses tend to be dimmer in the gamma-ray *** anti-correlation is accessible with an internal shock scenario.

关键词： gamma-rays:bursts-gamma-rays:observations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microstructure and Properties of Low Temperature Composite Chromized Layer on H13 Tool Steel

引用

Journal of Materials Science & technology 2005年第2期21卷 251-255页

作者： Cuilan WU, Chengping LUO and Ganfeng ZOU college of Mechanical Engineering, South china university of technology, Guangzhou 510641, china Coll. of Mech. Eng. South China Univ. of Technol. Guangzhou 510641 China

Low temperature composite chromizing is a process composed of a plain ion-carbonitriding or ion-nitriding at 550-580℃, followed by a low-temperature chromizing in a salt-bath of 590℃. The microstructure and properties of the low temperature composite chromized layer on H13 tool steel were investigated using metallography, X-ray diffraction, microanalysis, hardness and wear tests. It was found that this low temperature process was thermo-dynamically and kinetically possible, and the composite chromized layer on H13 steel, with a thickness of 3-6 μm, consisted of three sub-layers (bands), viz. the outer Cr-rich one, the intermediate (black) one, and the inner, original white layer. After chromizing, the former diffusion layer was thickened. The results of X-ray diffraction showed that the composite chromized layer contained such nitrides and carbides of chromium as CrN, Cr2N, (Cr, Fe)23C6, and (Cr, Fe)7C3, as well as plain α-(Fe, Cr). A high surface microhardness of 1450-1550 HV0.025, which is much higher than that obtained by the conventional ion carbonitriding and ion nitriding, was obtained. In addition, an excellent wear resistance was gained on the composite chromized layer.

关键词： H13 tool steel Low temperature composite chromizing Nitride and carbide of chromium Microhardness Wear resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fuzzy tolerance quotient spaces and fuzzy subsets

引用

Science china(Information Sciences) 2010年第4期53卷 704-714页

作者： ZHANG Ling1 & ZHANG Bo2,3,4* 1Computer Science & technology college, Anhui university, Anhui 230039, china 2State Key Laboratory of Intelligent technology and Systems, Beijing 100084, china 3Tsinghua National Laboratory of Information Science & technology, Beijing 100084, china 4Information Science & technology college, Computer Science & technology Department, Tsinghua university, Beijing 100084, china Computer Science & technology college Anhui University Anhui China State Key Laboratory of Intelligent technology and Systems Beijing China Tsinghua National Laboratory of Information Science & technology Beijing China Information Science & technology college Computer Science & Technology Department Tsinghua University Beijing China

The structure and characteristic of fuzzy subsets are discussed by using the concepts of granulation and hierarchy in quotient space theory. First, the equivalence relation based quotient space theory is extended to the fuzzy tolerance relation. Second, the isomorphism and its discriminant of fuzzy tolerance relations are discussed. Finally, by using the fuzzy tolerance relation to define the fuzzy subset, its properties are addressed. The main results are given below: (1) several equivalent statements of fuzzy tolerance relations; (2) the definition of isomorphism of fuzzy tolerance relations; (3) the isomorphic discriminant of fuzzy tolerance relations; (4) the definition and properties of fuzzy subsets based on the fuzzy tolerance relations; and (5) the necessary and sufficient condition of the isomorphism of fuzzy subsets. These results will help us further comprehend the concepts of fuzzy tolerance relations and fuzzy subsets.

关键词： Fuzzy tolerance relation quotient space isomorphism fuzzy subset

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Studies of negative pragmatic transfer in interlanguage pragmatics

引用

广西师范大学学报（哲学社会科学版） 2002年第S2期38卷 34-45页

作者： LIU Shao zhong, LIAO Feng rong (Foreign Languages college,guangxi Normal university, guilin 541004, china)

Negative pragmatic transfer (NPT) is nothing but a difference of saying things between non native speakers and native speakers. It occupies an important position in interlanguage pragmatics whose mission is to scrutinize how non native speakers do things with words with L2. This paper reported that 4 NPT related aspects have been heavily documented in the current literature: 1) L1 negative pragmatic transfers at the speech act level; 2) the distinction between negative pragmalinguistic and sociopragmatic transfers; 3) conditions of negative pragmatic transfers; and 4) native speaker’s attitudes towards L1 negative pragmatic transfers. Consequently, issues for future studies are also raised.

关键词： negative pragmatic transfer interlanguage pragmatics speech acts

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Free Volume Changes in γ-Irradiated Polyethylene and Polytetraflourethylene

引用

Journal of Materials Science & technology 2000年第3期16卷 302-304页

作者： Xianyi ZHOU (Dept. of Modern physics, university of Science and technology of china, Hefei 230027, china) Linhua ZHAI (Department of physics, Anhui Normal university, Wuhu 241000, china) Jiangfeng DU and Rongdian HAN (Department of Modern physics, Univers Department of Modern physics University of Science and Technology of China Hefei 230027 China Department of physics Anhui Normal University Wuhu 241000 China

Positron lifetime spectrum was measured and the change of the free volume was studied for commercial polyethylene (PE) and polytetrafluoroethylene (PTFE) during 7-irradiation processing up to 265 kGy. The free volume size increases but the crystallinity decreases as irradiation dose increases in PE. Both qualities (free volume size and crystallinity) in PTFE display an opposite behavior. The fractional free volume reduces monotonically with increasing irradiation dose in both PE and PTFE. The competition between the crosslinkmg and the splitting decomposition in polymers can be used to understand the free volume changes with irradiation dose.

关键词： PTFE Irradiated Polyethylene and Polytetraflourethylene

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

From the Green's Function in Tight-Binding Representation to Interatomic Many-body Potentials

引用

Journal of Materials Science & technology 1999年第4期15卷 315-319页

作者： Shaojun LIU(Department of physics, Beijing Normal university, Beijing 100875, china)Xiaobo WEI(Department of physics, Liuzhou college of Education, Liuzhou 545005, china)Zhaodou CHEN Jun CAI and Benkun MA(Department of physics, Beijing Normal university, Department of physics Beijing Normal University Beijing 100875 China Department of physics Liuzhou College of Education Liuzhou 545005 China

In this paper, we deduce the analytical form of many-body interatomic potentials based on the Green's function in tight-binding representation. The many-body potentials are expressed as the functions of the hopping integrals which are the physical origin of cohesion of atoms. For thesimple case of s-valent system, the inversion of the many-body potentials are discussed in detail by using the lattice inversion method.

关键词： Rev Li Chen From the Green’s Function in Tight-Binding Representation to Interatomic Many-body Potentials body

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：