分子束外延HgCdTe材料生长参数的实时监测研究

报道了用椭圆偏振技术和红外辐射测温技术对ＨｇＣｄＴｅ生长关键参数实时监测的结果，建立了ＨｇＣｄＴｅ材料在生长温度下的标准光学常数数据库，在研究中对生长过程中材料的发射率以及红外辐射强度进行了理论分析，为生长温度的实时精确控制提供了理论依据，并在实验上获得了小于±１℃的生长温度控制精度．     

无人值守MMDS机房设备运行状态遥控监视装置

我局的MMDS机房设在高山上,无人值守。信号源取自局内,与市区有线系统共用,通过无线方式传至山上。为了实时监视设备的运行状态、机房室内温度、电源供给等情况,我们设计制作了一套遥控监视装置。 本装置的特点一是不增加专用通道,而是利用正常的传输通道,在其空闲时间将摄取到监视画面下传,因而大大地节约资金,实际投资不足千元;二是操控简单方便,当需要监看时,只需将     

HT-6B TOKAMAK装置利用低混杂波驱动电流实现约束改善

在HT-6B TOKAMAK装置上,利用低混杂波驱动电流实现了等离子体约束改善,粒子约束时间增加2～6倍,等离子体内能增加一倍,低混杂波驱动电流改善约束存在一密度窗口:n_e=(0.3～1.5)×10¹³cm^-3,约束改善时伴随着边界快扰动的抑制和边界电子温度梯度的增大,此约束改善的功率阈值较低,最后讨论了此约束改善的物理机制,分析表明此约束改善现象可能是低混杂波在等离子体内产生一定数量具有一定能量的高能电子所造成.     

核聚变研究的发展历史

当代物理学重要前沿领域之一的受控核聚变研究近年来取得了重要进展.预计今后几年内能够从实验上证明其科学可行性并实现热核点火,这将会在科学史上写下光辉的一页. 早在 1919年,阿斯顿(F.W.Aston)在实验中发现[1]氦-4的质量比组成氦的 4个氢原子的质量之和大约小l%左右.根据爱因斯坦质能关系,其质量差恰好等于四个氢原子核聚合成一个氦-4时释放的能量.卢瑟福也几乎在同一时期证明了足够大能量的轻原子核相互碰撞可以发生核反应.天体物理学家也提出设想:太阳这样的恒星其能量来源于原子核的聚变反应.1920年,英国天体物理学家爱丁顿(Eddi-n…     

可探测眼底压力的植入式传感器

最近，德国杜伊斯堡（Duisburg）的科学家发明了一种集成传感器，该传感器可以作为永久性植入人体器件，长期监测诸如眼底、血管、膀胱或者脑部等部位可能产生的高压危害。     

The Analysis and Calculation on ECRH Anode Circuit on the HL-2A Tokamak

In the last year, ECRH system has been built in the HL-2A and the testing of gyrotron is also finished. In the project testing, one of the problems is current-peak occurring in the anode circuit of gyrotron. The current-peak is much larger than that of the value set in protection circuit. The frequent current-peak frequently occurring in the rising of anode-voltage often caused the protection circuit to mistaken trigger. The mistaken triggering often halted the normal gyrotron-testing. A set of equations of anode circuit are derived for analysis the phenomena of the current-peak. The calculation based on the deduced formula shows that value of the current-peak strongly depends on the inductance L, capacitance C and the ramp-time of anode voltage in the anode circuit. The conductance L and capacitance C are the characteristic inductance and capacitance of the cable that is used for anode HV power supply. The numerical calculation is exactly consistent with waveform of the current peak recorded by oscillograph, that means the derived formula are correct. In order to decrease the value of the current-peak, we should decrease capacitance C, and increase inductance L and ramp-time of anode voltage.     

Spectral Characteristics of Edge Electrostatic Turbulence in the HL-2A Tokamak

A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used to analysis the turbulence structure. It is found that the drift wave turbulence mainly is composed of low-frequency and long wavelength wave packets. The poloidal propagation is mainly in electron-diamagnetic direction, sometimes it propagates in ion-diamagnetic direction, which is influenced by Doppler-frequency shift. The radial propagation velocity is outward and the sizeable fraction of the poloidal velocity, implying that the radial mode plays an important role in the cross field transport.