Fabry-Perot干涉仪用于托卡马克等离子体氢氘比测量

本文在国内首次将Fabry-perot干涉仪用于托卡马克等离子体诊断。实验采用一台压电驱动式Fabry-perot干涉仪通过对H_α和D_α谱线轮廓的测量来推算等离子体的氢氘含量比,从而避免了在传统的氢氘比测量中因重复放电所引起的不准确性。     

用H_α光谱测量方法研究简单磁镜装置中热电子等离子体的性质

本文描述了简单磁镜装置中微波加热的氢等离子体的Ｈ_α面发光度特性的实验结果。与Ｘ射线、反磁探针、朗缪尔探针等测量结果相结合，给出了ＭＭ－２简单磁镜装置中ＥＣＲ等离子体的一些基本特性。     

HL-1M托卡马克中的中子通量和辐射剂量当量测量

用5台带有慢化剂(聚乙烯)的BF3₃正比计数管中子探测器测量中子通量和剂量当 量.4台 置于HL_1M装置的四周,分别测量了在氘等离子体条件下,因欧姆加热和波加热产生的热核聚 变中子产额、中子通量和剂量,以及氢等离子体条件下因高能x射线引起的光致核反应而产生 的光致中子. 另一台流动于其他6个观察点,主要监测中子剂量当量. 在D_D聚变条件下,实测 中子产额与计算值作比较,两者在数量级上大体一致. 中子辐射剂量当量远低于国家和部颁 标准,更低于国际防护委员会推荐的中子辐射允许剂量当量 关键词： 3正比计数管')" href="#">BF3₃正比计数管 光致中子 氘_氘聚变中子 剂量当量     

用作超声接收器的共焦Fabry-Perot干涉仪

自行研制了一台用作超声接收器的共焦Ｆａｂｒｙ－Ｐｅｒｏｔ干涉仪。本文介绍了用该类干涉仪探测固体表面超声脉冲的原理，给出了干涉仪参数选择的依据及其具体结构形式，估价了共焦状态的精度要求，获得了干涉仪的干涉图样及锯齿波扫描透射曲线等实验结果。同时将该干涉仪成功地应用于探测激光脉冲在金属固体中激励的超声脉冲。     

稠密氘和氢氘混合等离子体辐射不透明度的研究

用强平面激波对氘和氢氘等摩尔混合气体进行冲击压缩 ,产生密度约为 3.7× 10 - 3 — 7.0×10 - 3 g/cm3 等离子体.由记录的等离子体发光过程的上升前沿 ,确定了氘和氢氘等离子体光谱吸收系数随光学波长变化. Plasma is generated by passage of strong planar shock wave through gas. Initial experiments in deuterium and equal mol mixture of hydrogen and deuterium have been performed to produce plasma with 3.7×10 -3-7.0×10 -3 g/cm 3density. The variation of the opacity of the plasma with wavelength is measured by recording the risetime of the emitted light.     

氘－氚聚变等离子体中高能α粒子的诊断

本文对于用电荷交换方法或低杂波涨落的方法测量高能α粒子作了简短的评述，建议用核反应１３Ｃ（α，ｎ）１６Ｏ测量氘－氚聚变等离子体中的高能α粒子，并提出了一种减少杂质污染，增加穿透深度的方法。     

转镜调制二氧化碳激光干涉仪

耦合腔干涉仪是在激光器出现后才发展起来的新型干涉仪。由于其光路简单,易于调整,对等离子体无干扰等优点,已成为稠密等离子体密度测量的常用工具。如所周知,耦合腔激光干涉仪对等离子体电子密度测量的灵敏度为:     

法布里－珀罗干涉仪的发明

法布里－珀罗干涉仪的发明艾宝勤，胡其图（郑州轻工业学院基础部，郑州４５０００２）郭奕玲（清华大学现代应用物理系，北京１０００８４）１９世纪末期，马赛大学两位年轻的法国物理学家法布里（ＣｈａｒｌｅｓＦａｂｒｙ）和珀罗（ＡｌｆｒｅｄＰｅｒｏｔ）描述了一个...     

氢氘比的测量和粒子再循环

利用多道光学分析仪测量了HT－7托卡马克的氢氘比。通过一个简化模型讨论了氢氘比和粒子再循环的关系,并分析了氢氘比不容易控制的原因。     

基于电感耦合等离子体源的CO2色散干涉仪搭建和测试

在电感耦合等离子体源(ICP)装置上成功地搭建了一套没有减震系统的水平单道测量的CO₂色散干涉仪,用以测量等离子体的弦积分电子密度,并且与HCN干涉仪结果作对比,证明了CO₂色散干涉仪的可行性。     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.