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Magnetic properties of small Fe clusters: a nonorthogonal Hamiltonian study

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原子与分子物理学报 2000年第4期17卷 583-588页

作者： REN Yun 1.2 ,SUN hou qian 1.2 , WANG Bao lin 1. LUO You hua 1. WANG guang hou 1.1. National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 21.093 2.Yancheng Institute of Technology, Jia 南京大学固体微结构物理国家重点实验室江苏南京 210093

We calculate the magnetic properties of small Fe N clusters( N =2～7,9,1.,1.) by using a parameterized Hubbard tight binding spd band model Hamiltonian, with the parameters obtained from nonorthogonal Hamiltonian parameters. the average magnetic moments, and the spin polarized charge distribution within clusters are in agreement with those obtained by first principle and tight binding calculations. The effect of the nonorthogonal basis is discussed.

关键词：铁团磁性 Hubbard模型

Combinatorial Model Involving Travel Choice,Destination Choice and Route Choice

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Journal of Systems Science and Systems Engineering 2001年第4期13卷 425-432页

作者： ZHOU Xi-zhao1. YANG Xiao-guang2 1. Management School, Shanghai Maritime University, Shanghai 2001.5, China 2. Tong ji University, Shanghai 200092, China Management School Shanghai Maritime UniversityShanghai 200135 China Tongji University Shanghai 200092 China

Considering random utility of transportation information, the author develops combinatorial model involving travel choice, destination choice and route choice. It's uniqueness and equivalance are also proved. Finally,... 详细信息

关键词： travel choice destination choice: route choice

Modelling of Time Dependency of Chloride Diffusion Coefficient in Cement Paste

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Journal of Wuhan University of Technology(Materials Science) 2010年第4期25卷 687-691页

作者：张明中 Microlab Faculty of Civil Engineering and Geosciences Delft University of Technology Stevinweg 1 2628 CN Delft The Netherlands

A computer-based model and method was presented to predict the time dependency of chloride diffusion coefficients in cement paste. The HYMOSTRUC3D model was applied to generate a 3D representative elementary volume （REV） of cement paste. In the simulation of microstructure, both of cement hydration and chloride binding were considered. With the simulated microstructure of cement paste, the finite element method was applied to simulate the diffusion process of chloride through the saturated cement paste. Based on the Fick’s first law, the chloride diffusion coefficient can be calculated. In this method, the influences of age and w/c ratio on the chloride diffusion coefficient were evaluated. The simulated chloride diffusivities with various w/c at different time were compared to experimental data obtained from the literature. The experimental results indicate that the chloride diffusion coefficient decreases with the increase of time and the decrease of w/c ratio. The trend of simulated relationship （diffusion coefficient vs time, diffusion coefficient vs w/c ratio） fits very well with the experiments.

关键词： cement paste time dependency chloride diffusion coefficient chloride binding HYMOSTRUC3D

Status of study on biological and toxicological effects of nanoscale materials

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Science China Chemistry 2005年第5期48卷 385-394页

作者： WANG Bing1. FENG Weiyue1. ZHAO Yuliang1. XING Gengmei1. CHAI Zhifang1. WANG Haifang2 & JIA guang3 1. Laboratory for Bio-Environmental Health Sciences of Nanoscale Materials (Nanosafety Lab), Institute of High Energy Physics, Chi-nese Academy of Sciences, Beijing 1.0049, China 2. College of Chemistry and Molecular Engineering, Peking University, Beijing 1.0871. China 3. Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing 1.0083, China 1. Laboratory for Bio-Environmental Health Sciences of Nanoscale Materials (Nanosafety Lab) Institute of High Energy Physics Chinese Academy of Sciences 100049 Beijing China 2. College of Chemistry and Molecular Engineering Peking University 100871 Beijing China 3. Department of Occupational and Environmental Health Sciences School of Public Health Peking University 100083 Beijing China

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials, their potential impacts on human health and the envi-ronment will be topics under the serious discussions in press and in a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological activities and adverse effects of nanoscale materials/particles including single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron powders. Though some biological behaviors of nanoscale materials observed cannot be understood on the basis of the current knowledge, as the existing data are mostly preliminary, it is too early to make some ex-clusive conclusions on biological activities (or the toxicity) of any of nanoscale materials. The experimental techniques, the current topics, and the future research directions for this new re-search field are also discussed.

关键词： nanomaterials, single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron, biological activity and toxicological effect.

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多角度耦合分幅相机光学系统设计

中国光学 2018年第4期11卷 615-622页

作者：张天舒金光刘春雨中国科学院长春光学精密机械与物理研究所吉林长春130033 中国科学院大学北京100049

为实现高速相机的分幅功能,本文提出一种采用多角度耦合分幅方式的高速相机光学系统。该系统分幅结构采用多组相同的光学系统,在平行于物面的圆周上均匀分布,分别从不同角度拍摄同一物面,在保证各组系统的物方视场相同的情况下,每组光... 详细信息

为实现高速相机的分幅功能,本文提出一种采用多角度耦合分幅方式的高速相机光学系统。该系统分幅结构采用多组相同的光学系统,在平行于物面的圆周上均匀分布,分别从不同角度拍摄同一物面,在保证各组系统的物方视场相同的情况下,每组光学系统的光轴与物平面的夹角均相同,通过优化设计得到全视场的最佳成像。根据需求,使用光学设计软件设计了多角度耦合四分幅成像中长焦光学系统并绘制三维立体仿真模型,分析了每组像面像质、照度以及畸变等相关参数,调制传递函数MTF在频率为50 lp/mm处不低于0.5,F数为2,畸变小于0.4%,相较于常用的棱镜和反射棱锥分光方式,无需额外分光结构,像面照度提高4倍以上。结果表明成像质量理想,分幅相机系统各像面所成像一致性高。

关键词：光学设计分幅相机高速摄影

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大面积路堤荷载下带承台桩的荷载传递分析

土木工程学报 2009年第2期42卷 98-104页

作者：楼晓明孙晓锋陈广同济大学上海200092 江苏省交通规划设计研究院江苏南京210005

提出用迭代法分析大面积路堤荷载下带承台桩荷载传递特性的计算方法。将大面积路堤桩中的任意一根桩及其代表的桩间土看作一个存在相互作用力的柱杆系统,单个柱杆用荷载传递法分析,柱杆之间的相互影响用迭代法分析。该方法可简便地考虑... 详细信息

提出用迭代法分析大面积路堤荷载下带承台桩荷载传递特性的计算方法。将大面积路堤桩中的任意一根桩及其代表的桩间土看作一个存在相互作用力的柱杆系统,单个柱杆用荷载传递法分析,柱杆之间的相互影响用迭代法分析。该方法可简便地考虑桩、土、承台和路堤的相互作用,地基土的分层特性和桩身荷载传递函数的非线性。假定传递函数分别为线弹性全塑性和指数曲线的模型时,对双层地基中的路堤桩进行了算例分析,得到荷载分担比、等沉面、中性点、沉降、轴力、摩阻力等结果。讨论桩顶荷载分担比、中性点位置随填土高度、桩长和承台置换率的变化规律。计算桩顶荷载分担比与模型试验的中央桩实测结果大体一致,荷载传递特性与数值模拟结果也大体一致。

关键词：路堤带承台桩荷载传递函数桩顶荷载分担比

裂纹转子系统响应的阵发性混沌与时域分叉现象

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上海交通大学学报 2002年第6期36卷 824-828页

作者：秦卫阳孟光上海交通大学振动冲击噪声国家重点实验室西北工业大学振动工程研究所西安710072

建立了考虑摆振的 Jeffcott裂纹转子、双盘悬臂裂纹转子和支承在挤压油膜阻尼器上的裂纹转子的动力学模型 ,分析了这 3种裂纹转子系统响应的阵发性混沌与时域分叉现象 .结果表明 :这 3种模型中均出现了明显的阵发性混沌现象 ,且不仅存... 详细信息

建立了考虑摆振的 Jeffcott裂纹转子、双盘悬臂裂纹转子和支承在挤压油膜阻尼器上的裂纹转子的动力学模型 ,分析了这 3种裂纹转子系统响应的阵发性混沌与时域分叉现象 .结果表明 :这 3种模型中均出现了明显的阵发性混沌现象 ,且不仅存在着对应各种系统参数变化而产生的分叉与混沌行为 ,也存在着对应于时变参数而发生的时域分叉与混沌行为 ;转子系统的阵发性混沌是响应随时变参数的变化进入与退出混沌的行为 ,进入与退出的方式和时刻都具有随机性的特点 ;系统响应通向阵发性混沌的道路有通过拟周期响应 ,也有通过周期响应进入 ,且响应在进入阵发性混沌区前一般都有幅值增大的现象 ;裂纹转子的阵发性混沌中存在着倍周期分叉现象 ,并且有周期

关键词：裂纹转子系统阵发性混沌时域分叉挤压油膜阻尼器非线性响应转子动力学双盘悬臂裂纹转子

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一种基于空间分割前向竞争网络的性能探讨

四川大学学报（工程科学版） 2004年第4期36卷 83-86页

作者：徐晨曦陈光 电子科技大学自动化工程学院

在混合信号自动测试系统中,周期性模拟信号波形的识别是ATE自学习建库和自动测试、分析的关键。提出一种运用空间分割竞争网络结合Kohonen学习规则实现有规则模拟信号波形的识别方法,该方法用空间块归属的概念代替超平面分类,具有空间... 详细信息

在混合信号自动测试系统中,周期性模拟信号波形的识别是ATE自学习建库和自动测试、分析的关键。提出一种运用空间分割竞争网络结合Kohonen学习规则实现有规则模拟信号波形的识别方法,该方法用空间块归属的概念代替超平面分类,具有空间上离散分类的能力。重点讨论了通过软边界处理的Kohonen训练规则,该学习方法可将识别特征值分布特性通过软边界技术快捷地训练到寻址层隶属度矩阵中,克服由大样本训练实现空间块隶属度统计的不足,减少训练样本、提高学习速度。通过以信号十次谐波之和、信号一周面积及信号正负面积之比为特征,识别几类常见信号波形为例,表明该方法对波形识别的实用性。

关键词：空间分割竞争网络软边界处理识别特征

The Computer Aided Integrated Design and Analysis of Oil Tank in Vehicle

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厦门大学学报（自然科学版） 2002年第S1期41卷 269-页

作者： CHEN Xu 1. CHEN Yong-guang 2 (1. Mechanical Engineering Institute, Chongqing University, Chongqing 400044, China 2. Logistical Engineering University, Chongqing 40001., China)

This paper creates 3D solid model and assembly of U RJ 92-6 oil tank and analyses its strength by integrated CAD/CAE/CAM software I-D EAS. Through integrated simulation in computer, design efficiency and quality of oil tank is greatly improved. Adopting integrated CAD/CAE/CAM software to carry out integrated research to equ ipment and products, we will be able to take overall analysis in aspects of 3-D solid modeling, pre-assembly and strength, etc., to realize non-paper designi ng and parallel designing. Problems can be found and settled during designing, w hich will increase designing efficiency and one-time success rate and realize o ptimum designing for products.

关键词： oil tank solid modeling finite element analysis integrated design