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利用红外相机对HL-2A装置外偏滤器靶板的表面温度进行了测量,得到了具有一定时空分辨的红外热图。用一维热传导模型对热点处的温升进行数据处理,得到了轰击点上的热负荷演变曲线。分别对辐射偏滤器、ECRH加热、中性束注入、破裂四种放电情况下的热负荷曲线进行了分析,并就辐射偏滤器和破裂两种放电的热负荷与靶板探针测得的结果进行了比较。     

Time-resolved radial uniformity of pulse-modulated inductively coupled O_2/Ar plasmas

Time-resolved radial uniformity of pulse-modulated inductively coupled O_2/Ar plasma has been investigated by means of a Langmuir probe as well as an optical probe in this paper. The radial uniformity of plasma has been discussed through analyzing the nonuniformity factor β(calculated by the measured n_e, lower β means higher plasma radial uniformity). The results show that during the active-glow period, the radial distribution of ne exhibits an almost flat profile at the beginning phase, but it converts into a parabola-like profile during the steady state. The consequent evolution for β is that when the power is turned on, it declines to a minimum at first, and then it increases to a maximum, after that, it decays until it keeps constant. This phenomenon can be explained by the fact that the ionization gradually becomes stronger at the plasma center and meanwhile the rebuilt electric field(plasma potential and ambipolar potential) will confine the electrons at the plasma center as well. Besides, the mean electron energy( ε_(on)) at the pulse beginning decreases with the increasing duty cycle. This will postpone the plasma ignition after the power is turned on. This phenomenon has been verified by the emission intensity of Ar(λ = 750.4 nm). During the after-glow period, it is interesting to find that the electrons have a large depletion rate at the plasma center. Consequently, ne forms a hollow distribution in the radial direction at the late stage of after-glow. Therefore, β exhibits a maximum at the same time. This can be attributed to the formation of negative oxygen ion(O~-) at the plasma center when the power has been turned off.     

SnO分子的X~1∑~+,a~3Π和A~1Π态的势能曲线与光谱性质

对O原子以aug-cc-pvTZ为基组,Sn原子以aug-cc-pvTZ-PP为基组,分别采用多参考组态相互作用方法(MRCI)及运用Davidson修正的多参考组态相互作用方法对SnO分子基态X~1Σ~+及两个激发态a~3Π和A~1Π态的势能曲线进行计算,进而得到了各态的平衡键长R_e,谐振频率w_2,非谐振常数ω_ex_e,转动常数B_r,垂直跃迁能T_e以及离解能D_e,通过群论原理确定了各电子状态和离解通道,计算结果表明:3个电子态有共同的离解通道,即Sn(~3p)+O(~3p);利用Level程序对势能曲线进行拟合得到的光谱数据表明,MRCI方法的计算结果与实验值符合更好;通过求解核运动的Schrodinger方程得到了J=0时这三个电子态的前30个振动态的B_v和D_v等分子常数和振动能级E。     

LiAl分子基态、激发态势能曲线和振动能级

利用单双激发多参考组态相互作用方法获得了LiAl分子基态X¹∑⁺及七个激发态a³∏, A¹∏, b³∑⁺, c³∑⁺, B¹∏, C¹∑⁺, d³∏的势能曲线, 通过势能曲线得到各态的平衡核间距R_e, 进而求得绝热激发能和垂直激发能.计算结果表明:c³∑⁺ 电子态是一个不稳定的排斥态, A¹∏态是一个较弱的束缚态, 其余6个电子态均为束缚态; b³∑⁺与 c³∑⁺态之间存在预解离现象; 8个电子态分别解离到两个通道, 即Li(²S)+Al(²P⁰)与Li(²P⁰)+Al(²P⁰). 接着将势能曲线拟合到Murrel-Sorbie解析势能函数形式, 据此获得各态的光谱数据:基态X¹∑⁺的平衡键长为0.2863 nm, 谐振频率为316 cm^-1, 解离能D_e为1.03 eV, 激发态a³∏, A¹∏, b³∑⁺, c³∑⁺, B¹∏, C¹∑⁺, d³∏的垂直激发能依次为0.27, 0.83, 1.18, 1.14, 1.62, 1.81, 2.00 eV; 解离能依次为1.03, 0.82, 0.26, 排斥态, 1.54, 1.10, 0.93 eV, 相应谐振频率 ω_e为339, 237, 394, 排斥态, 429, 192, 178 cm^-1. 通过求解核运动的薛定谔方程找到了J=0时 LiAl分子7个束缚电子态的振动能级和转动惯量. 关键词： LiAl 光谱常数 势能曲线 振动能级     

Pressure-induced solidifications of liquid sulfur below and above λ-transition

Two kinds of glassy sulfurs are synthesized by the rapid compression method from liquid sulfur at temperatures below and above the λ-transition point. The glassy sulfur has different colors and transparencies, depending on temperature, which may inherit some structural information from the λ-transition. Raman spectrum studies of these samples show that a large fraction of polymeric chains exist in the glassy sulfur, even in the one solidified from T T_λ. We find that a higher compression rate instead of a higher temperature of the parent liquid captures more polymeric chains. Pressure-induced glassy sulfur presents high thermal stability compared with temperature quenched glassy sulfur and could transform into liquid sulfur directly without crystallization through an abnormal exothermic melting course. High energy x-ray diffraction is utilized to study the local order of the pressure-induced glassy sulfur.     

Na_2~+离子较低电子态势能曲线和光谱常数的理论研究

通过多组态相互作用方法,结合原子有效芯势与极化势,利用非收缩的高斯基函数,计算了Na_2~+分子对应最低9个解离限的36个电子态的势能曲线.基于计算获得的束缚态势能曲线,拟合给出了相应的光谱常数,并与已有的实验和理论结果进行了比较.同时,给出了部分电子态的振动-转动能级和一些同类态避免交叉点的信息.计算获得的光谱信息对冷原子分子光谱与动力学的研究具有参考价值.     

Parallel propagating modes and anomalous spatial damping in the ultra-relativistic electron plasma with arbitrary degeneracy

The dispersion relations of parallel propagating modes(Langmuir mode, right and left handed circular polarized waves) in the weak magnetic field limit |ω-k·v| ? are considered for ultra-relativistic arbitrary degenerate electron plasma. The results are presented in terms of moments of Fermi-Dirac distribution. The increase in the electron equilibrium number density from negative large(weakly degenerate) to positive large(highly degenerate) values of μ/T_e is observed(where μ is the electron chemical potential and T_e is the electron thermal energy). As a result, shifting of the cutoff points in all the real dispersion branches towards the higher values and increasing in the band gap between unmagnetized longitudinal and transverse modes in k-space are examined. Also, the suppression of the weak magnetic field effects in weakly magnetized right handed and left handed circular polarized waves and a decrease in the longitudinal and transverse screening effects are observed in the graphical patterns due to an increase in the equilibrium number density.     

EAST辐射偏滤器充气系统改造及初步实验结果

介绍了EAST偏滤器充气系统的改进措施,压电阀与冷屏一起安装在EAST颈管中,以缩短充气管道,将充气系统的延迟时间减少约200ms。冷屏起冷却阀门并屏蔽电磁场的作用。讨论了在准稳态条件下,延迟时间给偏滤器热流反馈控制带来的负面效应。在中性束加热条件下,通过在外靶板注入Ar/D2(1:4)混合气体研究了靶板离子饱和流和热流分布的变化及充气对主等离子体的影响,得到了靶板离子饱和流显著降低、热流减少的结果。     

氙等离子体输运性质计算

采用基于将Chapman-Enskog方法扩展到高阶近似的方法计算获得了温度范围在300—40000 K,不同压力条件下氙等离子体的黏性、热导率和电导率.热力学平衡条件下的计算结果与文献报道的实验和计算结果符合良好,验证了计算方法和结果的合理性与准确性.在此基础上,计算获得了电子温度(T e)不等于重粒子温度(T h)的热力学非平衡和化学平衡条件下氙等离子体的输运性质,并分析了输运性质随压力和热力学非平衡程度变化的原因.     

EAST新型下偏滤器冷却结构 传热性能数值模拟

为实现EAST装置超400s长脉冲高约束模、10MW加热功率下的稳态运行，需对现有的下碳偏滤器进行升级改造，拟采用钨串结极水冷却系统，热通量控制在水冷钨铜第一壁材料允许的稳态的10MW·m^-2。在对下钨偏滤器的冷却结极传热性能进行数值模拟仿真研究的基础上，研究了多种以钨串单元为基础的冷却结极，提出了一种新型下钨偏滤器水冷结极设计，幵建立了满足传热要求的EAST装置新型下钨偏滤器单元结构模型。     

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介绍了EAST偏滤器充气系统的改进措施,压电阀与冷屏一起安装在EAST颈管中,以缩短充气管道,将充气系统的延迟时间减少约200ms。冷屏起冷却阀门并屏蔽电磁场的作用。讨论了在准稳态条件下,延迟时间给偏滤器热流反馈控制带来的负面效应。在中性束加热条件下,通过在外靶板注入 Ar/D2(1：4)混合气体研究了靶板离子饱和流和热流分布的变化及充气对主等离子体的影响,得到了靶板离子饱和流显著降低、热流减少的结果。     

Numerical study on the gas heating mechanism in pulse-modulated radio-frequency glow discharge

The gas heating mechanism in the pulse-modulated radio-frequency(rf) discharge at atmospheric pressure was investigated with a one-dimensional two-temperature fluid model. Firstly, the spatiotemporal profiles of the gas temperature(T_g)in both consistent rf discharge and pulse-modulated rf discharge were compared. The results indicated that T_gdecreases considerably with the pulse-modulated power, and the elastic collision mechanism plays a more important role in the gas heating change. Secondly, the influences of the duty cycle on the discharge parameters, especially on the T_g, were studied.It was found that T_gdecreases almost linearly with the reduction of the duty cycle, and there exists one ideal value of the duty cycle, by which both the T_gcan be adjusted and the glow mode can be sustained. Thirdly, the discharge mode changing from α to γ mode in the pulse-modulated rf discharge was investigated, the spatial distributions of T_gin the two modes show different features and the ion Joule heating is more important during the mode transition.     

PS自由基X2Π态的势能曲线和光谱性质

采用Davidson修正的内收缩多参考组态相互作用方法(icMRCI+Q) 结合Dunning等的相关一致基计算了PS自由基X²Π 态势能曲线. 利用三阶Douglas-Kroll Hamilton近似结合cc-pV5Z相对论收缩基进行了相对论修正计算. 利用aug-cc-pCV5Z基组对势能曲线进行了核价相关修正计算, 并将总能量外推至完全基组极限. 拟合得到了X²Π态的主要光谱常数R_e, ω_e, ω_ex_e, ω_ey_e, B_e, α_e 和D_e, 与实验结果符合较好. 利用Breit-Pauli算符, 研究了旋轨耦合效应对势能曲线的影响, 得到了两条Ω 态的势能曲线. 详细分析了在旋轨耦合计算中, 核电子相关与冻结核近似对电子结构和光谱性质的影响. 在icMRCI+Q/56+DK+CV+SO理论水平上得到了两个Ω 态的主要光谱常数T_e, R_e, ω_e, ω_ex_e, ω_ey_e, B_e 和α_e, 结果与实验结果一致. 在平衡位置处, 本文的X²Π态旋轨耦合能量分裂值为 323.73 cm^-1, 与实验结果321.93 cm^-1较为一致. 通过求解双原子分子核运动的径向Schrödinger方程, 找到了无转动PS自由基X²Π态及其两个Ω 态的全部振动态, 还分别计算了它们相应的振动能级和惯性转动常数等分子常数, 这些结果与已有的实验值一致. 关键词： 势能曲线 光谱常数 分子常数 旋轨耦合     

HL-2M装置常规偏滤器与雪花减偏滤器热工水力分析对比

采用SOLPS程序模拟预测HL-2M装置常规和雪花减偏滤器靶板上的热通量。当流入边缘等离子体区域的热功率约为10MW时,利用CFX/ANSYS软件分析这两类偏滤器各结构、冷却水温度分布及形变和热应力分布情况。结果表明:等离子体总功率相同,雪花减偏滤器靶板上的最高温度比常规偏滤器低169℃;雪花减偏滤器结构所承受的最大热应力和形变比常规偏滤器低约3/7。不改变热负载剖面分布,按一定比例提升热流密度或延长放电时间,雪花减偏滤器体现出比常规偏滤器靶板温升低、冷却水温均衡等优点。因此,雪花减偏滤器能处理更多流进偏滤器区域的热能,有效地降低偏滤器工程设计要求。     

Magnetostriction and spin reorientation in ferromagnetic Laves phase Pr(Ga_xFe_(1-x))_(1.9) compounds

The magnetostriction, magnetization, and spin reorientation properties in Pr(Ga_xFe_(1-x))_(1.9) alloys have been investigated by high-precision x-ray diffraction(XRD) step scanning, magnetization, and Mo¨ssbauer spectra measurements. Ga substitution reduces the magnetostriction(λ_(||)) with magnetic field H ≥ 8 kOe(1 Oe = 1.33322×10~2 Pa), but it also increases the λ|| value when H ≤ 8 kOe at 5 K. Spin-reorientations(SR) are observed in all the alloys investigated, as determined by the step scanned XRD, Mo¨ssbauer spectra, and the abnormal temperature dependence of magnetization. An increase of the spin reorientation temperature(T_(SR)) due to Ga substitution is found in the phase diagram, which is different from the decrease one in many R(T_x Fe_(1-x))_(1.9)(T = Co, Al, Mn) alloys. The present work provides a method to control the easy magnetization direction(EMD) or T_(SR) for developing an anisotropic compensation system.     

Dy3Al5O12磁热性质研究

用量子理论计算了Dy₃Al₅O₁₂的晶场能谱、Zeeman劈裂能级和波函数. 在外磁场H_e为0<H_e<9 T, 温度为3<T<42 K 范围内, 计算了该晶体的磁矩、磁熵变, 计算结果与相关实验数据吻合较好. 该计算结果表明, Dy₃Al₅O₁₂内磁性离子间的交换作用非常微弱, 可以忽略. 从理论上给出了绝热退磁过程中温度变化ΔT与T的关系, 并与Gd₃Ga₅O₁₂晶体进行了比较, 发现不同外磁场下, Dy₃Al₅O₁₂和Gd₃Ga₅O₁₂的低温制冷性能在不同温区有差别. 在进行低温(T<10 K)制冷时, 若外磁场较低, 选择Dy₃Al₅O₁₂作为磁制冷材料较好; 若外磁场较高, 选择Gd₃Ga₅O₁₂作为磁制冷材料较好.     

CFETR氦冷偏滤器初步设计与分析

基于中国聚变工程试验堆(CFETR)偏滤器位形,初步设计了指状、平板和 T 形三种氦冷偏滤器模型, 在 10MPa 入口氦压力、10MW⋅m⁻² 稳态热负荷下,分别对其进行传热数值分析。通过优化结构设计和氦入口参数, 降低了靶板工作温度,探索了三种单元结构靶板处理高热负载的能力。在 20MW⋅m⁻² 的稳态热负荷下,对优化后 的 T 形和指状单元结构进行了受热分析,并由此提出了混合型 CFETR 氦冷偏滤器初步结构。      

Electric biasing of the divertor tiles in compass-D

It has been suggested that by electrically biasing the divertor tiles in a tokamak, one could create a toroidally-asymmetric potential structure in the scrape-off layer (SOL) plasma. The resultingE×B convective motion should increase the plasma transport in the SOL and thereby reduce the heat load on the divertor plates. This paper describes plans for such experiments on COMPASS-D and preliminary theoretical modelling. The COMPASS-D divertor target consists of 24 graphite tiled toroidal segments. The inner and outer strike point tiles on all these segments will be insulated from each other, and cabling will be installed to allow for biasing of individual tiles in any combination. Theoretical analysis suggests that the electrostatic potential perturbations caused by the biasing will be confined to the divertor region below the X-point, and that substantial SOL broadening can be achieved by applying modest voltages. Aside from active control of SOL transport, it is hoped that the biasing will be useful to probe other divertor and SOL physics issues. Presented at the Workshop on the Role of Electric Fields in Plasma Confinement and Exhaust, Budapest, 18–19 June, 2000. This work was jointly funded by the UK Department of Trade and Industry and Euratom, and was supported by US DoE under contract W-7405-ENG-48 at LLNL.     

聚变堆熔盐冷却偏滤器靶板结构设计与分析

为提高偏滤器的抗中子辐照能力,兼顾高热承载能力和聚变堆经济性的需要,提出了基于熔盐冷却(MSC)的偏滤器靶板结构设计。它采用FLiNaK作为冷却剂,钨镧合金为热沉材料,钨为第一壁材料。通过数值计算评估了靶板的热负荷承载能力,并完成了偏滤器冷却剂回路设计,优化了偏滤器各模块之间的流量分配。此MSC偏滤器靶板设计可以有效去除10~15MW•m^-2热负荷,为适应未来聚变堆偏滤器靶板发展的需要提供了一种设计解决方案。     

Effective activation energy Ue(T,J,H) in textured Bi1.84Pb0.4Sr2Ca2Cu3Oy silver-clamped thick films

We have measured the resistivity of textured Bi_1.84Pb_0.4Sr₂Ca₂Cu₃O_y silver-clamped thick films as a function of temperature, current density ranging from 10 to 1×10³ A/cm² and magnetic field up to 0.3 T. We find that the effective activation energy U_e follows U_e(T,J,H)=U₀(1−T/T_p)^mln(J_c0/J)H⁻ with m=1.75 for Hab-plane and 2.5 for Hc-axis and =0.76 for Hab and 0.97 for Hc, for the current density regime above 100 A/cm², where T_p is a function of applied magnetic field and current density. This result suggests the effective activation energy U_e be correlated with the temperature, current density and magnetic field. The possible dissipative mechanisms responsible for the temperature, current density and magnetic field dependence of the effective activation energy are discussed.