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.     

螺旋波激发氢等离子体光谱诊断

利用一套螺旋波激发等离子体化学气相沉积（HWP—CVD）发生装置及发射光谱采集装置，原位诊断了不同入射功率、气压、氢气流量下氢等离子体光谱，研究了激发态氢原子的变化情况、氢分子振动温度的变化和激发态氢分子的相对分布。结果表明：     

Simulation of polarization-insensitive multiple-quantum-well superluminescent diodes

The 1.3-μm polarization-insensitive superluminescent diodes (SLDs) with weak tensile strained multiplequantum-well (MQW) and complex strained MQW were demonstrated theoretically based on the simulation of energy band structure and gain spectra at different injected carrier densities. Compared with the weak tensile strained MQW, the complex strained MQW gets higher modal gain and better modal gain matching between TE and TM modes, and the polarization sensitivity of TE and TM optical spectra can remain less than 1.0 dB over a bandwidth of 200 nm.     

大学物理实验教学内容与方法改革探索

面对科学技术的飞速发展和现代社会对人才的要求,针对现阶段大学物理实验教学中普遍存在的问题,结合我校在大学物理实验教学改革的实际情况,提供了一系列大学物理实验教学改革的新思路和新方法。     

驻波法测定超声波声速实验的探究

本文推导了驻波法测超声声速实验中合成声场的位移波动方程、声压波动方程及两者之间的关系。进一步剖析合成声场的性质,从而获得对合成声场更加客观的认识。     

浅议物理实验教学改革

本文在指出物理实验教学中存在问题的同时，对实验教学的管理和教学方法的改革问题进行了探讨。     

基于uCLinux的网络驱动程序开发

本文论述了Linux下网络设备驱动程序的基本原理、实现过程，并介绍在uCLinux中网络驱动程序的开发方法。     

HL-2A装置边缘等离子体参数测量

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。HL-2A装置主真空室的活动马赫／雷诺协强／朗缪尔10探针阵列具有很高的时间和空间分辨能力，能够直接测量边缘等离子体参数并研究边缘扰动和相关特性。大量的实验表明：约束的改进与旋转速度的增加和边缘涨落的下降密切相关。