检索结果-南通市图书馆

A VIRTUAL MESH METHOD FOR THE OPTIMIZED DESIGN OF COMPLEX STRUCTURES

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 Mechanica Solida Sinica 2003年第3期16卷 220-230页

作者： Du Taisheng Huang Rongjie Song Tianxia Chen Chuanyao (College of Civil Engineering and mechanics,huazhong University of {2. and {3.,wuhan 43.074,china) CollegeofCivilEngineeringandmechanics HuazhongUniversityofScienceandTechnologyWuhan430074China

Concepts for a virtual 3. space and a hyper-sphere are proposed and the formulae for determining the computable nodes of the mesh are *** a new optimization design method('Virtual Mesh Method'or V.M.M)is *** examples are given,showing that the method proposed is especially suitable for the optimized design of complex structures,and that the global approximate optimal solution can be searched with remarkably reduced computational work.

关键词： virtual 3. space computable nodes n-D hyper-sphere optimization design virtual mesh method

Terahertz radiation sources based on free electron lasers and their applications

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2012年第1期55卷 1-15页

作者： TAN Ping1,HUANG Jiang2.LIU KaiFeng2.XIONG YongQian2.FAN MingWu1,2.1department of Electronic and Information Engineering,huazhong University of {2. and technology,wuhan 43.074,china 2.ollege of Electrical and Electronic Engineering,State Key Laboratory of Advanced Electromagnetic Engineering and technology,huazhong University of {2. and technology,wuhan 43.074,china 1. department of Electronic and Information Engineering Huazhong University of Science and Technology Wuhan 430074 China2. College of Electrical and Electronic Engineering State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

The tunability,high power and flexible picoseconds-pulse time structure of terahertz(THz)radiation make the THz free-electron laser(FEL)a very attractive THz source of coherent *** paper focuses on the development and perspectives of THz radiation sources based on the *** principles of the low gain THz FEL oscillator,the SASE THz FEL amplifier and the supperradiant THz FEL are reviewed briefly,and the key technologies of THz FEL,such as injector,accelerator,undulator and optical cavity,are discussed,*** current status of and future prospects for THz radiation sources based on the FEL are emphasized in this *** research and development have shown bright future in free-electron laser(FEL)THz radiation *** potential applications can be carried out in the field of imaging,material research,biology medicine,communication,diagnostics and many others.

关键词： terahertz source terahertz applications free electron laser

Positive Periodic Solution for a Nonautonomous Delay Differential Equation

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 Mathematicae Applicatae Sinica 2003年第2期19卷 307-316页

作者： Bing Liudepartment of Mathematics, huazhong University of {2. and {3., wuhan 43.074, china department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China

Abstract In this paper, by using the Krasnoselskii fixed point theorem, we study the existence of one or multiple positive periodic solutions of a nonautonomous delay differential equation. We also give some examples ... 详细信息

关键词： Positive periodic solution delay differential equation Krsnoselskii fix point theorem

PARALLEL LATTICE BGK SIMULATION OF NATURAL CONVECTION IN A CAVITY

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2005年第5期17卷 564-570页

作者： SHI Bao-chang LIU Hong-juan Parallel Computing Institute Huazhong University of Science and Technology Wuhan 430074 China department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China

A Coupled Lattice Bhatnagar Gross Krook （CLBGK） model was proposed with a robust boundary scheme to model the Bossinesq incompressible flows. The LBGK method is a powerful approach, but is also computationally demanding. Therefore, parallel computing was implemented, and the codes were run on the parallel computer “Lenovo DeepComp 1800” with 2. nodes written in C＋＋ using the Message Passing Interface （MPI） library. Numerical results for natural convection in a cavity with the Rayleigh number （ Ra ） ranging from 10^6 to 4× 10^10 were presented, and found to agree well with the previous work. And with the increase of the resolution rate, the accuracy has been greatly improved. In addition, new models were set up by applying different equilibriums to the CLBGK model to simulate the same problem, which all yield sound results.

关键词： Lattice Bhatnagar Gross-Krook ( LB( K )model, Lattice Boltzmann Method (LBM), natural convection, parallel computing, high resolution

Electrical Measurement to Assess Hydration Process and the Porosity Formation

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan University of technology(Materials {2.) 2008年第5期23卷 761-766页

作者：魏小胜 department of Civil Engineering Huazhong University of Science and Technology

The change of electrical resistivity with time at early ages was used to investigate the hydration process and the porosity development. Porosity reduction process of cement-based materials hydration was developed by a proposed method. The porosity reduction is fast at the setting period. The results find that the pore discontinuity occurs faster at lower water/cement ratios than at higher water/cement ratios which is similar to the results of the Percolation method.

关键词： electrical resistivity hydration setting time percolation

Direct CP violation in hadronic B decays

在线全文

学校读者我要写书评

暂无评论

science china(Physics,{2. & Astronomy) 2006年第3期49卷 357-366页

作者： HONG Bihai1,2.& Lü Caidian3.1. department of Physics, Lishui University, Lishui 3.0}000,{3. 2. department of Physics, Shanghai Jiaotong University, Shanghai 2.003., {3. 3. Institute of High Energy Physics, Beijing 100049,{3. department of Physics Lishui University Lishui 323000 China department of Physics Shanghai Jiaotong University Shanghai 200030 China Institute of High Energy Physics Beijing 100049 China

There are different approaches for the hadronic B decay calculations, recently. In this paper, we upgrade three of them, namely factorization, QCD factorization and the perturbative QCD approach based on kT factorization, using new parameters and full wave functions. Although they get similar results for many of the branching ratios, the direct CP asymmetries predicted by them are different, which can be tested by recent experimental measurements of B factories.

关键词： CP violation hadronic B decay factorization.

Ferroelectric properties of Bi_4Zr_(0.5)Ti_(2.5)O_(12. thin films prepared on LaNiO_3.bottom electrode by sol-gel method

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2007年第4期50卷 472-477页

作者： GUO DongYun1, LI MeiYa1, LIU Jun1, PEI Ling1, YU BenFang1, ZHAO XingZhong1, YANG Bin2. WANG YunBo2.& YU Jun2.1 {3. of Physics, wuhan University, wuhan 43.072. china 2.{3. of Electronic science and technology, huazhong University of science and technology, wuhan 43.074, china 1. department of Physics Wuhan University Wuhan 430072 China 2. department of Electronic science and {2. Huazhong University of Science and Technology Wuhan 430074 China

The Bi4Zr0.5Ti2.5O12.(BZT) thin films were fabricated on the LaNiO3.bottom electrode using sol-gel method. The structure and morphology of the films were character-ized using X-ray diffraction, AFM and SEM. The results show that the films have a perovskite phase and dense microstructure. The 2.r and 2.c of the Pt/BZT/LaNiO3.capacitor are 2..2.μC/cm2.and 14.7 V respectively at an applied voltage of 2. V. After the switching of 1×1010 cycles, the Pr value decreases to 87% of its pre-fatigue val-ues. The dielectric constant (ε) and the dissipation factor (tanδ) of the BZT thin films are about 2.4 and 0.02. at 1 kHz, respectively. The films show good insulating behavior according to the test of leakage current. The clockwise C-V hysteresis curve observed shows that the Pt/BZT/LaNiO3.structure has a memory effect be-cause of the BZT film’s ferroelectric polarization.

关键词： Bi_4Zr_(0.5)Ti_(2.5)O_(12. thin film sol-gel method LaNiO_3.bottom electrode ferroelectric properties

Secure, dependable and publicly verifiable distributed data storage in unattended wireless sensor networks

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第5期53卷 964-979页

作者： REN Wei 1 , REN Yi 2.& ZHANG Hui 3.1 School of Computer science, china University of Geosciences (wuhan), wuhan 43.074, china 2.department of Information and Communication technology, University of Agder (UiA), Norway 3.department of Electronics, Politecnico di Torino (POLITO), Italy 1. School of Computer science China University of Geosciences (Wuhan) Wuhan 430074 China2. Department of Information and Communication Technology University of Agder (UiA) Kristiansand Norway3. Department of Electronics Politecnico di Torino (POLITO) Torino Italy

In unattended wireless sensor networks (UWSNs), sensed data are stored locally or at designated nodes and further accessed by authorized collectors on demand. This paradigm is motivated by certain scenarios where historical or digest data (e.g., average temperature in a day), instead of real-time data, are of interest. The data are not instantly forwarded to a central sink upon sensing, thereby saving communication energy for transmission. Such a paradigm can also improve data survivability by making use of distributed data storage in cheap flash memory on nodes. However, the security and dependability of such data storage are critical for the future data accessibility in UWSNs. To address this issue, we propose a secure and dependable distributed storage scheme for UWSNs. Our scheme takes advantages of both secret sharing and Reed-Solomon code, which can achieve computational security and maintain low communication overhead in terms of shortened data dispersing size. We also propose a general coding method to publicly verify data integrity in a distributed manner, with low communication and storage overhead, and without the need of holding original data. The extensive analysis justifies that our scheme can provide secure, dependable and publicly verifiable distributed data storage in UWSNs even in the presence of node compromise and Byzantine failure.

关键词： secure storage dependability data integrity wireless sensor networks wireless network security

Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons

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(Physics,{2. & Astronomy) 2010年第4期53卷 672-679页

作者： MA Jun 1,2. TANG Jun 2., ZHANG AiHua 3.& JIA Ya 2.1 {3. of Physics, Lanzhou University of technology, Lanzhou 73.050, {2. 2.{3. of Physics, Central {2. Normal University, wuhan 43.079, {2. 3.College of Electrical and Information Engineering, Lanzhou University of technology, Lanzhou 73.050, {2. 1. department of Physics Lanzhou University of Technology Lanzhou 730050 China2. Department of Physics Central China Normal University Wuhan 430079 China3. College of Electrical and Information Engineering Lanzhou University of Technology Lanzhou 730050 China

The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.

关键词： spiral wave factor of synchronization breakup multiplicative noise robustness