自由边界螺旋对称磁流体平衡的数值研究

用自洽平衡方程数值求解了自由边界螺旋对称平衡,并未发现如非自洽方法计算所得到的磁岛结构。在存在l=2螺旋绕组时,等离子体截面呈椭圆变形,与解析结果定性一致。     

托卡马克理想导体壁与磁流体不稳定性

为了探索等离子体磁流体力学(MHD)不稳定性的导体壁效应以及壁设计思想,研究了基于HL-2A托卡马克偏滤器位形的、自由边界和多种形式的理想导体壁条件下的等离子体MHD不稳定性与装置MHD运行β极限.在稳定性计算中,考虑的是n=1扭曲模,该模对托卡马克等离子体MHD不稳定性有决定性的影响.研究着眼于验证多种形状导体壁抑制内、外扭曲模的有效性,观察运行β极限的变化,并讨论分析相关物理.研究发现在离等离子体适当距离处放置一个理想导体壁,可有效抑制外扭曲模.在壁与等离子体表面的平均距离相同、且足够小的条件下,圆截面壁并不一定是最佳选择,设置一个经过优化的多边形导体壁能更有效地抑制MHD不稳定性,它使本装置的理想MHD运行β极限β_N提高到2.73,比自由边界条件下(即假设壁设置在无穷远处的)装置的运行β极限值(～2.56)提高了约6.5%.这暗示需要根据有拉长、有变形的等离子体的极向截面形状,优化制作一个离等离子体表面平均距离尽可能近的多边形导体壁,才能取得抑制外扭曲模、提高β极限的最佳效果.     

Effects of trapped electrons on off-axis lower hybrid current drive in tokamaks

The effects of trapped electrons on off-axis lower hybrid current drive （LHCD） in tokamaks are studied, A computer code for solving the Fokker-Planck equation in a toroidal geometry is developed and employed. The code is suitable for various auxiliary heating and current drive schemes in tokamak plasmas. The influence of the resonance regime on the current drive efficiency as well as the influence of trapped particle fraction on the current drive efficiency are emphasized. It is shown that, as an electrostatic force, the lower hybrid wave causes some of the trapped electrons to be untrapped and lose their energy, which can cut the LHCD efficiency by about 30%. The ITER scaling law is also used to estimate the trapped electron effects.[第一段]     

添加Fe对Pt/KL沸石芳构化及抗硫性能的影响

Pt／KL沸五催化剂对正己烷的芳构化反应具有特别高的活性和选择性，但是它对原料中硫的存在非常敏感，要求合硫量小平川’，而工业催化剂的硫含量允许10’．这使得Pt／KL佛石催化剂一直未能工业化山．近年来，文献上开始出现了一些KL佛石上负载双金属的研究工作［’－’1．通过     

Exact surface energy and elementary excitations of the XXX spin-1/2 chain with arbitrary non-diagonal boundary fields

We study the physical properties of the XXX spin-1/2 chain with arbitrary non-diagonal boundary fields. By using a combination of numerical analysis and analytical method, we obtain the surface energy and elementary excitations of the model. It shows that the contributions of the two boundary fields to the surface energy are additive. We also find that there exists a kind of excitations related to the boundary string.     

Ce(Ⅲ),Dy(Ⅲ)与四异丙基亚甲基双膦酸酯配合物的合成与光谱表征

在乙腈溶液中合成了三种镧系金属三氟甲基磺酸盐Ln(OTf)3(Ln=Ce,Dy)与四异丙基亚甲基双膦酸酯[L=(iPrO)2P(O)CH2P(O)(iPrO)2]配合物[CeL4](OTf)3.2H2O,[Dy(OTf)2L2(H2O)2](OTf)(CH3CN)和[DyL4](OTf)3.L.2H2O。荧光分析发现,[CeL4](OTf)3.2H2O在波长249和300 nm激发下,测得641 nm处有明显的发射峰,Dy3 的两种配合物中[Dy(OTf)2L2(H2O)2](OTf)(CH3CN)中有水参与配位,使得其发射和激发峰的强度均弱于没有水参与配位的[DyL4](OTf)3.L.2H2O。另外,通过元素分析,热重分析,红外光谱和核磁共振等手段对配合物进行了组成确定和光谱学表征,并初步确定了膦氧配体与稀土离子的配位模式。这三种配合物均是八配位模式,[CeL4](OTf)3.2H2O和[DyL4](OTf)3.L.2H2O呈现高的对称性,4个L配体作为双齿配体全部参与配位,而[Dy(OTf)2L2(H2O)2](OTf)(CH3CN)中Dy3 周围除两个L和两个OTf外,还有2个配位水。     

Observation of E×B Flow Velocity Profile Change Using Doppler Reflectometry in HL-2A

A broadband, O-mode sweeping Doppler reflectometry designed for measuring plasma E×B flow velocity profiles is operated in HL-2A. The main feature of the Doppler reflectometry is its capability to be tuned to any selected frequency in total waveband from 26-40 GHz. This property enables us to probe several plasma layers within a short time interval during a discharge, permitting the characterization of the radial distribution of plasma fluctuations. The system allows us to extract important information about the velocity change layer, namely its spatial localization. In purely Ohmic discharge a change of the E×B flow velocity profiles has been observed in the region for 28 〈 r 〈 30cm if only the line average density exceeds 2.2×10^19 m^-3. The density gradient change is measured in the same region, too.