期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
Theoretical investigation of band-gap and mode characteristics of anti-resonance guiding photonic crystal fibres 被引量:1
1
作者 苑金辉 桑新柱 +5 位作者 余重秀 忻向军 张锦龙 周桂耀 李曙光 侯蓝田 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第2期302-310,共9页
With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM), the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in an... With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM), the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in anti- resonance guiding photonic crystal fibres (ARGPCFs) are sufficiently analysed. An ARGPCF operating in the near- infrared wavelength is shown. The influences of the high index cylinders, glass interstitial apexes and silica structure on the characteristics of band-gaps and modes are deeply investigated. The equivalent planar waveguide theory is used for analysing such an ARGPCF filled by the isotropic materials, and the resonance and the anti-resonance characteristics r:~n h~ w~|] r^r~dlrtpd 展开更多
关键词 anti-resonance guiding photonic crystal fibres full-vector plane-wave method full-vector beam propagation method band-gap and mode characteristics
下载PDF
Design of a Metasurface Antenna Based on Characteristic Mode Theory
2
作者 HE Huan 《电讯技术》 北大核心 2024年第10期1561-1568,共8页
A novel metasurface antenna consisting of 5×5 rectangular patch elements is presented.Thestructure with and without the central element are both analyzed by the Characteristic Mode Theory(CMT).The developed mutua... A novel metasurface antenna consisting of 5×5 rectangular patch elements is presented.Thestructure with and without the central element are both analyzed by the Characteristic Mode Theory(CMT).The developed mutually orthogonal principal modes of the optimized periodic patch structure areexcited by a center-feed dipole.A differential feeding network is employed to realize impedance matching.Prototype with profile height of 0.07λ_(0)(λ_(0)is the wavelength in free space at the lowest operatingfrequency)is fabricated and assembled to verify the simulation results.The measured results show that thereflectance coefficient of proposed matesurface antenna is less than-10 dB in the whole operating bandrange from 4.2 GHz to 5.5 GHz,a relative bandwidth of 26.8%is achieved,and the maximummeasured realized gain is more than 9 dBi with a maximum radiation efficiency of 90%.The designprovides a guideline on the application of characteristic modes(CMs)to radiation problems. 展开更多
关键词 metasurface antenna characteristic mode theory dipole antenna realized gain
下载PDF
Study of Mode Characteristics for Equilateral Triangle Semiconductor Microlasers 被引量:2
3
作者 Qiao-Yin Lu, Xiao-Hong Chen, Wei-Hua Guo, Li-Juan Yu, Yong-Zhen Huang State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China, Tel: 010-82304524, E-mail: luqy@redsemi.ac.cnJian Wang and Yi LuoState Key Laboratory of Integrated Optoelectronics, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China 《光学学报》 EI CAS CSCD 北大核心 2003年第S1期329-330,共2页
InGaAsP semiconductor ETR microlasers with side length of 5 and 10 um are fabricated by ICP etching. The peaks in photoluminenscent spectra corresponding to longitudinal modes are observed with the interval consisting... InGaAsP semiconductor ETR microlasers with side length of 5 and 10 um are fabricated by ICP etching. The peaks in photoluminenscent spectra corresponding to longitudinal modes are observed with the interval consisting with the theoretical formulae. 展开更多
关键词 for in on with ICP Study of Mode Characteristics for Equilateral Triangle Semiconductor Microlasers of
原文传递
Characteristic mode analysis of wideband high-gain and low-profile metasurface antenna
4
作者 Kun Gao Xiang-Yu Cao +2 位作者 Jun Gao Huan-Huan Yang Jiang-Feng Han 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第6期275-281,共7页
A wideband high-gain and low-profile metasurface antenna is proposed by analyzing characteristic quantities and parameters in the characteristic modes(CMs). The detailed modal current and modal weighting coefficient a... A wideband high-gain and low-profile metasurface antenna is proposed by analyzing characteristic quantities and parameters in the characteristic modes(CMs). The detailed modal current and modal weighting coefficient are analyzed to explain the broadband operation and high gain. A dominant characteristic mode is well excited, leading to a broadband operation. The mode behaviors of the excitation are changed to suppress the unwanted higher-order modes and improve the radiation performance by changing the widths of two patches. The measured impedance bandwidth for-10 dB is 39.8%(5.3 GHz–7.94 GHz) with a gain of 7.8 dBi–10.04 dBi over the operating bandwidth. 展开更多
关键词 characteristic mode analysis WIDEBAND high gain metasurface antenna
下载PDF
A comprehensive comparison on vibration and heat transfer of two elastic heat transfer tube bundles 被引量:7
5
作者 闫柯 葛培琪 翟强 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期377-385,共9页
Elastic heat transfer tube bundles are widely used in the field of flow-induced vibration heat transfer enhancement. Two types of mainly used tube bundles, the planar elastic tube bundle and the conical spiral tube bu... Elastic heat transfer tube bundles are widely used in the field of flow-induced vibration heat transfer enhancement. Two types of mainly used tube bundles, the planar elastic tube bundle and the conical spiral tube bundle were comprehensively compared in the condition of the same shell side diameter. The natural mode characteristics, the effect of fluid-structure interaction, the stress distribution, the comprehensive heat transfer performance and the secondary fluid flow of the two elastic tube bundles were all concluded and compared. The results show that the natural frequency and the critical velocity of vibration buckling of the planar elastic tube bundle are larger than those of the conical spiral tube bundle, while the stress distribution and the comprehensive heat transfer performance of the conical spiral tube bundle are relatively better. 展开更多
关键词 planar elastic tube bundle conical spiral tube bundle mode characteristics heat transfer performance
下载PDF
Extraction of Basic Trends of Urban Expansion in China over Past 40 Years from Satellite Images 被引量:4
6
作者 WEN Qingke ZHANG Zengxiang +10 位作者 SHI Lifeng ZHAO Xiaoli LIU Fang XU Jinyong YI Ling LIU Bin WANG Xiao ZUO Lijun HU Shunguang LI Na LI Minmin 《Chinese Geographical Science》 SCIE CSCD 2016年第2期129-142,共14页
If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and th... If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and this is presently lacking. In this study, remotely sensed images with approximately 30 m spatial resolution were used to quantitatively assess the spatial and temporal patterns of urban expansion of 60 Chinese cities(1973–2013). Urban-expansion-process curves of the cities studied were drawn using annual expansion area as an indicator. Curve similarity analysis generated four basic process modes of urban expansion in China. These included cities that: 1) peaked around 2004 and then decelerated; 2) peaked around 2010 and then decelerated; 3) showed sustained acceleration, and 4) showed continued deceleration. Four basic process modes represented cities under different levels of development stage. Geographic location was found to be the most related characteristic to urban expansion process. Regional development policies at the national level in each region also showed highly temporal consistency with fluctuation characteristics of urban expansion process. Urban characteristic such as population size and administrative level were not found to be significantly related to urban expansion-process modes. Understanding the basic process-mode categories well is extremely important for future regional-balance planning and development of macroeconomic policies. 展开更多
关键词 urban expansion urbanization expansion-process mode long term urban development stage curve similarity urban characteristic
下载PDF
Construction of Transgenic Crop Germplasm Effective Function and Characteristic Analysis
7
作者 DING Guangzhou WANG Xiaowei 《Journal of Northeast Agricultural University(English Edition)》 CAS 2008年第2期68-75,共8页
Germplasm effect reflects the quantitative relation between production ability of germplasm elements and yield (quality) of a certain crop, which can be shown by mathematic function, namely, germplasm effect functio... Germplasm effect reflects the quantitative relation between production ability of germplasm elements and yield (quality) of a certain crop, which can be shown by mathematic function, namely, germplasm effect function. Germplasm effect of a crop variety is an aggregation of many effective factors, and is restrained by different effective factors; constant increase of any one effect of germplasm elements would lead to law of effect decline, therefore, possible modes of transgenic crops effect function were deduced according to the law of effect decline. The possible modes of single transgenic germplasm effect function and multi-transgenic germplasm effect regression equation were discussed, and the characteristics of germplasm effect regression equation were analyzed in this paper. 展开更多
关键词 transgenic crops germplasm effect function mode and characteristic germplasm operation
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部