检索结果-南通市图书馆

Nonlinear Optical Loop MirrorUsed to Compensate the Second Order Distortion in Analog Link

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 1997年第1期B6卷 49-52页

作者： HE Huajie HAN Yuguo GU Wuanyi LEE Guorui XU Daxiong(beijing university of Posts and Telecommunications,beijing 100088,{3.) beijing Univ of Posts and Telecommunications Beijing China

The change of the slope of the tansmissivity of a nonlinear optical loop mirror(NOLM) at given wavelength by adjusting the polarization in the loop is reported. The interaction between the transmissivity of NOLM and laser chirping can compensate the total second order distortion produced by all elements in the link dramatically under certain conditions.

关键词： nonlinear optical loop mirror second order distortion Er-doped fiber amplifier

Average Widths of Sobolev-Wiener Classes with Mixed Smoothness in L_q(R^d)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2001年第2期17卷 305-312页

作者： He Ping WANG Department of Mathematics, Capital Normal university. beijing, 10003., P. R. china Department of Mathematics Capital Normal University Beijing 100037 P. R. China

In this paper, the average σ-K width of Sobolev-Wiener classes Spqr W with mixed smooth- ness in Lq（Rd） is studied for 1

关键词： Sobolev-Wiener classes with mixed smoothness Average σ-K width Step hyperbolic crosses

NOTES　ON　FINITE　ELEMENT　METHOD　AND　ITS　GENERALIZATION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1996年第3期8卷 97-101页

作者： L. Tao (Institute of Mechanics, Chinese academy of sciences, beijing 100080, P. R. {3.)G. Q. Chen (Center for Environmental sciences, Peking university, beijing 100871, P. R. {3.)K. R. Rajagopal (Department of Mechanical Engineering, university of Pit

This paper generalizes the finite element method and discusses the issues of weighting functions, residual and realization of the integral conservation laws.

关键词： Finite element conservation laws

Application of the wavelet transforms on axial strain calculation in ultrasound elastography

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第9期16卷 942-947页

作者： LUO Jianwen, BAI Jing and SHAO Jinhua (Department of Biomedical Engineering, School of Medicine, Tsinghua university, beijing 100084, china) [a]Department of Biomedical Engineering School of Medicine Tsinghua University Beijing China

In ultrasound elastography, the axial strain distribution within biological tissues is calculated as the numerical derivative (differentiation) of the estimated axial displacement field. Unfortunately, the numerical derivative is unstable because it can greatly amplify the noises, especially at high frequencies. This work focuses on the axial strain calculation from the estimated axial displacements using wavelet transforms (WTs), including continuous wavelet transforms (CWTs) and discrete wavelet transforms (DWTs). The feasibility of the WT-based method using the quadratic spline function is verified by computer simulations and some phantom data. Results indicate that the WT-based method can effectively reduce the noise amplification in axial strain calculation.

关键词： ultrasound elastography axial strain differentiation wavelet transforms.

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

转辙机动作杆中光纤应力传感器的研究

铁道学报 2004年第6期26卷 120-122页

作者：孙强周虚北京交通大学电子信息工程学院北京100044 北京邮电大学电信工程学院北京100876

研究了非对称刻蚀光纤应力传感器的基本原理,将其应用在转辙机中,为转辙机动作杆应力的检测提供了一种新的测试方法。

关键词：光纤传感器转辙机动作杆应力

Stability of fMRI activation:evidence from fusiform face area

在线全文

学校读者我要写书评

暂无评论

Stability of fMRI activation:evidence from fusiform face are...

Isolation and Characterization of Novel Variants of HMW Glutenin Subunits Genes from the St Genome of Pseudoroegneria Stipifolia and Elytrigia Stipifolia

中国神经科学学会第九届全国学术会议暨第五次会员代表大会

作者： Bing CHEN~(1,2),Wei LEI~3.Jie XI~4,Xu-Chu WENG~(2,*) 1 Xiamen university,Xiamen 3.1005,china 2 Hangzhou Normal university,Hangzhou 3.0015,china 3.Southwest university,Chongqing 400715,china 4 Institute of Psychology,Chinese academy of sciences,beijing 10010,china

＜正＞Objective Fusiform face area（FFA） is highly specialized for faces and independent of task modulation. This study was to test the stability of FFA response to face information across 4 fMRI scans spanning one year in the same group of *** Block design was adopted and the stimuli included English words,Chinese characters,and *** Linear Model（GLM） was performed to define the ROI（region of interested）,i.e.,the FFA,in each *** stability of space coordinates of activation voxels within the ROI was analyzed by within-subject *** The coordinates of the voxels in the FFA ROI were highly reproducible across the 4 scans whether the ROI was defined by face *** or face *** The position of the FFA measured by fMRI is remarkably *** is feasible to use the FFA as a reference region in fMRI studies on the visual system.

关键词： Fusiform face area General Linear Model within-subject

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Isolation and Characterization of Novel Variants of HMW Glut...

Exact Periodic-Wave Solutions for(2+1)-Dimensional Boussinesq Equation and (3.1)-Dimensional KP Equation

植物分子生物学与现代农业——2010全国植物生物学研讨会

作者： Li Zhixin~1 Cao Shuanghe~2 Zhang Xiangqi~(2*) Zhang Huaigang~3.1 Institute of Crop Genetics and Breeding,Yangtze university,Jingzhou City,Hubei Province.china 2 Institute of Genetics and Developmental Biology,Chinese academy of {3.,beijing,china 3.Northwest Institute of Plateau Biology,Chinese academy of {3.,Xining,china

The x- and y-type high molecular weight(HMW) glutenin subunits are conserved seed storage proteins in wheat and related *** we characterized the HMW glutenin subunits from Pseudoroegneria stipifolia(StSt genomes) and Elytrigia stipifolia (StStStSt genomes) *** electrophoretic mobilities of the HMW glutenin subunits from *** and *** were much faster than those of

关键词： HMW glutenin subunit Pseudoroegneria stipifolia Elytrigia stipifolia phylogenetic analysis evolution

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2004年第8期42卷 239-241页

作者： ZHAO Qiang LIU Shi-Kuo FU Zun-Tao School of Physics, Peking university, beijing 100871, china School of Physics Peking University Beijing 100871 China

The(2+1)-dimensional Boussinesq equation and(3.1)-dimensional KP equation are studied by using theextended Jacobi elliptic-function *** exact periodic-wave solutions for the two equations are obtained.

关键词： Jacobi elliptic-function method (2+l)-dimensional Boussinesq equation (3.l)-dimensional KP equation periodic-wave solutions

A heuristic algorithm for cube packing with time schedule

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Information sciences) 2010年第1期53卷 18-29页

作者： LI Wei1, HUANG WenQi2, JIANG DongChen1 & LIU XiangLong1 1State Key Laboratory of Software Development Environment, Beihang university, beijing 100191, china 2School of Computer Science and Technology, Huazhong university of Science and Technology, Wuhan 43.074, china 1. State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China2. School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

Packing problem has been proved to be an NP-hard problem. Many algorithms such as simulation annealing algorithm, genetic algorithm and other heuristic algorithms have been proposed to solve twodimensional and three-dimensional packing problem. To solve the cube packing problem with time schedule, this paper first introduces some concepts such as packing level, space distance and average neighbor birth order and then proposes a greedy algorithm. The algorithm tries every feasible corner greedily to calculate the space utilization, packing level, space distance, average neighbor birth order of this placement, and chooses the best placement according to these criteria. Theoretical analysis indicates that the time complexity of this algorithm is O(A2B2C2T 2n5). The experiments show that the average space utilization of non-guillotine cutting test cases is 98.81%, and the average space utilization of guillotine cutting test cases achieves 99.87%. Furthermore, optimal solutions of more than half cases are achieved by this algorithm. The experimental results show that this algorithm can solve the problem of cube packing with time schedule effectively and effciently.

关键词： cube packing problem time schedule packing level space distance average neighbor birth order