检索结果-内蒙古大学图书馆

Nanjing Youdian Xueyuan Xuebao/Journal of Nanjing Institute of Posts and Telecommunications 2005年第6期25卷 12-16页

作者： Qin, Wei-Ping Ding, Sheng-Gao Zhang, Ye-Rong College of Mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing 210003 China College of Communication and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China

The short path propagation of an electromagnetic pulse generated numerically from a wideband conical monopole antenna through reinforced concrete wall of buildings has been studied in the time-domain using the finite-difference time-domain (FDTD) method. Computational results demonstrated the effects of the reinforced concrete wall on pulse signal propagation including the pulse waveform distortion made of transmitting antenna, field distribution when pulse propagating through wall, reflection of pulse peak and pulse waveform reflected from and transmitted through reinforced concrete wall.

关键词： Electromagnetic pulse propagation finite-difference time-domain method Reinforced concrete wall Ultra-wideband communication

来源：评论

学校读者我要写书评

暂无评论

Analysis of guided modes in photonic crystal fibers using the finite-difference time-domain method

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2001年第5期30卷 327-330页

作者： Qiu, M Royal Inst Technol Dept Electromagnet Theory S-10044 Stockholm Sweden

An efficient finite-difference time-domain method is proposed for the full-wave analysis of guided modes in photonic crystal fibers. The three-dimensional hybrid guided modes can be calculated by a two-dimensional mesh, if one assumes that the propagation constant along the z-direction (propagation direction) is fixed. Furthermore, only real variables are used in the present method. Therefore, the computation time and computer memory are significantly reduced. The results for a honeycomb-based silica-air photonic crystal fiber are in very good agreement with the results from the plane-wave expansion method. (C) 2001 John Wiley & Sons, Inc.

关键词： photonic crystal fibers finite-difference time-domain method photonic crystals

来源：评论

学校读者我要写书评

暂无评论

Numerical modelling of multi-dimensional liquid crystal optics: finite-difference time-domain method

引用

MOLECULAR CRYSTALS AND LIQUID CRYSTALS 2001年第1期359卷 609-619页

作者： Kriezis, EE Elston, SJ Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

Light wave propagation within complex liquid crystal structures is undertaken by the FDTD method, a purely numerical method that explicitly solves Maxwell's equations in space and time. A specific FDTD arrangement suitable for liquid crystal applications is described, allowing for efficient space termination, oblique angles of illumination, and correct phasor representation. Two application examples are considered: a two-domain twisted pixel formed by two oppositely twisted sub-domains, and a helical ferroelectric liquid crystal material. In each case comparison is also made with the optical prediction obtained by the Berreman method.

关键词： finite-difference time-domain method LC optics

来源：评论

学校读者我要写书评

暂无评论

Novel method for analyzing the transient behavior of grounding systems based on the finite-difference time-domain method

Novel method for analyzing the transient behavior of groundi...

引用

Winter Meeting of the IEEE-Power-Engineering-Society

作者： Tanabe, K CRIEPI Elect Insulat Dept Cent Res Inst Elect Power Ind Tokyo 2018511 Japan

ISBN: (纸本)0780366727

When lightning strikes bulk transmission lines or electric substations, large currents flow through towers or in substations and equipment structures before dissipating in the ground through the grounding systems. The electromagnetic fields generated by such lightning surges cause large currents and voltages, which may result in damage to equipment and serious accidents, such as failure of electrical transmission, and furthermore may be dangerous to personnel working nearby. Moreover, the immunity level of recent electronic equipment that contains semiconductors and LSI devices is low, and such equipment is sensitive to various types of electromagnetic stimuli. Therefore, it is important to analyze the transient behavior of grounding systems of power systems in order to study lightning protection and improve human safety. However. the transient behavior of grounding systems has so far been difficult to evaluate. In this paper, we propose a novel method in which the transient behavior is analyzed based on the finite-difference time-domain method, and confirm its validity through comparison between experimental results of the transient behavior and analytical results.

关键词： lightning protection human safety EMC grounding resistance transient phenomena simulation finite-difference time-domain method

来源：评论

学校读者我要写书评

暂无评论

Numerical modelling of multi-dimensional liquid crystal optics: finite-difference time-domain method

Numerical modelling of multi-dimensional liquid crystal opti...

引用

VIIIth International Topical Meeting on Optics of Liquid Crystals (OLC 99)

作者： Kriezis, EE Elston, SJ Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

关键词： finite-difference time-domain method LC optics

来源：评论

学校读者我要写书评

暂无评论

finite-difference time-domain analysis of band structures in one-dimensional Kerr-nonlinear photonic crystals

引用

OPTICS COMMUNICATIONS 2004年第1-3期239卷 213-222页

作者： Maksymov, IS Marsal, LF Pallarès, J Univ Rovira & Virgili Dept Engn Electron Elect & Automat Tarragona 43007 Spain

We present a new approach for analyzing band structures in one-dimensional Kerr-nonlinear photonic crystals. It combines the finite-difference time-domain method, based on the numerical simulation of oscillating dipole radiation, with the Kerr-nonlinear model. The approach is applied to analyze the band structures in Kerr-nonlinear one-dimensional photonic crystals as a function of the intensity of the oscillating dipole. We find that these bands are dynamically red-shifted with regard to the bands in linear one-dimensional photonic crystals. The proposed approach will help to understand such phenomena as intensity-driven optical limiting and all-optical switching with Kerr-nonlinear photonic crystals. (C) 2004 Elsevier B.V. All rights reserved.

关键词： one-dimensional nonlinear photonic crystal finite-difference time-domain method oscillating dipole band structure dynamic red-shift

来源：评论

学校读者我要写书评

暂无评论

finite-difference time-domain simulation of low-F# Fresnel zone plates coupled to IR antennas

Finite-difference time-domain simulation of low-F# Fresnel z...

引用

Conference on Electro-Optical and Infrared Systems

作者： Rico-García, JM López-Alonso, JM Lail, B Boreman, G Alda, J Univ Complutense Madrid Sch Opt Madrid 28037 Spain

ISBN: (纸本)0819455652

Fresnel Zone Plate Lenses (FZPLs) have been successfully coupled to infrared (IR) antennas producing a responsivity enhancement of about two orders of magnitude. However, their lateral extension may compromise their applicability in focal-plane-arrays (FPA) IR imagers, where the dimensions of the pixel are constrained by the FPA spacing. When designing optimum-gain FZPLs for FPAs, we are lead to the requirement of FZPLs operating at very low F/#s (marginal rays propagating at a large angle in image space). In this case, finite-difference time-domain techniques (FDTD) are used to refine the physical-optics modelling results, producing a result closer to the actual case encountered in a high-fill-factor FPA. In this contribution, we analyze the FZPL designs by using FDTD techniques. The main result of the FDTD computation is the gain factor defined as the ratio of the response of the IR antennas coupled with the FZPL, compared to the same antennas without the FZPL.

关键词： Antennas finite-difference time-domain method Silicon Computer generated holography Infrared imaging Staring arrays Semiconducting wafers Zone plates Computer simulations Infrared radiation

来源：评论

学校读者我要写书评

暂无评论

finite-difference time-domain analysis of ultrashort laser pulse propagation in a fiber with nonlinear effects

引用

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 2004年第5期87卷 1-10页

作者： Nakamura, S Koyamada, Y Karasawa, N Sone, H Morita, R Yamashita, M Ibaraki Univ Dept Media & Telecommun Engn Hitachi Ibaraki 3168511 Japan Japan Sci & Technol Corp Core Res Evolut Sci & Technol Promot Kawaguchi 3320012 Japan Chitose Inst Sci & Technol Fac Photon Sci Chitose 0668655 Japan Kitami Inst Technol Fac Engn Kitami Hokkaido 0908507 Japan Hokkaido Univ Dept Appl Phys Sapporo Hokkaido 0618628 Japan

As a method of analyzing the nonlinear propagation of light, the Sellmeier equation for fused silica with three resonant frequencies is used and a finite-difference time-domain method taking the Raman response into account is proposed. The numerical results are compared with experimental results for optical pulses with a pulse width of 12 fs passing through a fused silica fiber. By this method of analysis, the numerical results are compared with those obtained by the conventional split-step Fourier method and it is found that these results are closer to the experimental results. (C) 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1 ,87(5): 1-10, 2004;Published online in Wiley InterScience (***). DOI 10.1002/ ecja.10166.

关键词： finite-difference time-domain method optical fiber nonlinear optics femtosecond Raman Sellmeier equation

来源：评论

学校读者我要写书评

暂无评论

Numerical investigation of the effective dimensions of perfect electric conductor (PEC) in FDTD simulation

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2004年第2期40卷 107-109页

作者： Zhou, BX Wang, SC Yu, WH Nanjing Normal Univ Coll Elect & Elect Engn Nanjing 210042 Peoples R China Penn State Univ Electromagnet Commun Lab University Pk PA 16802 USA

In this communication, we present all improvement technique for the finite-difference time-domain (FDTD) method, in which an accurate solution call be achieved using a very coarse mesh if a weighted factor of the simulated PEC object dimension is properly selected. A uniform microwave stripline is used to validate the proposed scheme. (C) 2004 Wiley Periodicals, Inc.

关键词： finite-difference time-domain method stripline numerical methods

来源：评论

学校读者我要写书评

暂无评论

Axial focusing characteristics of diffractive micro-lenses based on a rigorous electromagnetic theory

引用

JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS 2004年第12期6卷 1067-1071页

作者： Feng, D Yan, YB Jin, GF Fan, SS Tsing Hua Univ State Key Lab Precis Measurement Technol & Instru Dept Precis Instruments Beijing 100084 Peoples R China Tsing Hua Univ Dept Phys Tsinghua Foxconn Nanotechnol Res Ctr Beijing 100084 Peoples R China

In order to determine the assembling error at the receiving plane and to obtain the maximum energy efficiency, it is necessary to study the axial focusing characteristics of diffractive micro-lenses such as the focal depth and the focal shift. When the diffractive optical elements' features are of the order of or smaller than the wavelength of the incident illumination, their electromagnetic characteristics must be considered. By using a two-dimensional finite-difference time-domain (FDTD) method, we present a rigorous electromagnetic analysis of diffractive micro-lenses that are finite in extent, in the case of a normally incident light wave. Compared with the scalar theory, the axial intensity distributions of diffractive micro-lenses are analysed rigorously, for different incidence polarizations (TE polarization and TM polarization), different profile structures (continuous profile, 16-level profile, 8-level profile, and 2-level profile) and different f-numbers of lenses. The numerical results show that the focal shifts calculated by the electromagnetic theory are larger than those made by the scalar theory, and the focal depths calculated by these two methods are basically consistent. The focal depth and the focal shift will increase when the f-number increases, for both the rigorous electromagnetic theory and the scalar theory.

关键词： diffractive micro-lenses electromagnetic theory finite-difference time-domain method axial focusing characteristics

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：