外腔任意反馈半导体激光器的频率调谐特性

根据半导体激光器外腔反射率的不同，系统地研究了外腔任意反馈半导体激光器的频率调谐特性，理论分析及数值模拟与实验结果基本一致。     

HL-2A装置偏滤器运行模式的探针测量

HL-2A装置是一个具有偏滤器位形的托卡马克装置，为我们开展先进偏滤器物理实验和改善主等离子体约束性能研究准备了良好的条件。等离子体的杂质含量由杂质源分布以及SOL和芯部等离子体中各种杂质输运过程确定。由于离子碰撞可导致狭窄的偏滤器入口部件处杂质溅射的增强，与起源于靶板处的杂质相比，偏滤器入口处的杂质更有效地污染芯部等离子体。     

Filter Performance of a Cesium Faraday Optical Filter at 852nm

We have investigated a cesium Faraday filter at 852nm in relatively weak and strong magnetic fields,theoretically and experimentally.with a cesium cell of 0.02m length in an axial magnetic field of 0.06T,the line-centre operation has been achieved.The calculated peak transmission reached 99% with a full width at half maximum (FWHM) bandwidth of only 3.9GHz.The measured FWHM bandwidth of the filter is 3.29GHz,which is in general agreement with the theoretical result.     

和静绿洲景观格局特征分析

基于景观生态学空间格局理论分析和静绿洲景观格局．选用和静县1999年LANDSAT TM影像，运用ARC／INFO对影像进行目视判读和数字化工作．利用景观统计软件Fragstats For Arcview分别计算一些常用的景观指数．通过运用景观空间理论对景观指数进行分析，得出和静绿洲总体景观格局特征．     

数学教学中应重视创新意识的培养

创新意识表现为:能理解新颖的信息、情境和设问,选择有效的方法和手段分析信息,综合与灵活地应用所学的数学知识、思想和方法,进行独立的思考、探索和研究,提出解决问题的思路,创造性地解决问题.……     

数学教学中应重视创新意识的培养

创新意识表现为:能理解新颖的信息、情境和设问,选择有效的方法和手段分析信息,综合与灵活地应用所学的数学知识、思想和方法,进行独立的思考、探索和研究,提出解决问题的思路,创造性地解决问题.……     

Self Mixing Fringes of Vertical-Cavity Surface-Emitting Lasers under Dual Reflector Feedback

The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed. Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensors has been improved by 10 times. The role of the each reflector has been discussed in detail.     

Superluminal Behaviour of Modified Bessel Waves

Much experimental evidence of superluminal phenomena has been available by electromagnetic wave propagation experiments, with the results showing that the phase time describes the barrier traversal time. Based on the extrapolated phase time approach and numerical methods, we show that, in contrast to the ordinary Bessel waves of real argument, the group velocities of modified Bessel waves are superluminal. We obtain the following results. The group velocities increase with the increase of propagation distance, which is similar to the evanescent plane- wave cases. For large wave numbers, the group velocities fall off as the wave numbers increase, which is similar to the evanescent plane-wave cases. For small wave numbers, the group velocities increase with the increase of wave numbers, this is different from the evanescent plane-wave cases.     

研究性课题的研究报告

一目标(1)深层次的了解有关线性规划的内容,从中掌握一定方法,提高分析问题和解决问题的能力. (2)通过掌握的知识为生活服务,做到学以致用.     

Pellet Enhanced Performance on the HL-2A Tokamak

Enhanced confinement has been achieved by the centre fuelling of pellet injection on the HL-2A tokamak. The energy confinement time increases from 50ms to 140ms after the pellet injection. Experimental results show that the improvement of the confinement is related to the decrease of the electron heat transport. Several phenomena which may lead to the improved confinement have been observed in the experiments. After the pellet injection the hollow electron temperature profile and the peaked electron density profile can be sustained for about 200ms, but the improved confinement remains at about 500ms. Sawtooth features and MHD modes have been observed by soft x-ray array and the Mirnov probes. The weak （or reversed） magnetic shear is thought to be an important cause of the low electron heat transport.