HL-1M装置第一壁锂-硅复合涂层及其效果

在HL-1M装置上新开发出一种第一壁原位锂-硅复合涂覆技术。装置涂覆后，真空室内的真空度上升，杂质气体的分压强下降，低于单一的硅化或锂涂覆。在相同放电参数下，具有锂-硅涂层的放电与原位硅化放电相比；等离子体中的氧杂质浓度下降了30%，尤其是随着等离子体密度上升碳杂质下降得更显著；等离子体能量辐射损失降低了25%；等离子体边缘温度和密度有所降低，这表明等离子体内部约束得到改善，有原位锂-硅复合涂覆的放电结果略好于或同于单一原位锂涂覆放电的结果，但这种复合涂层能维持100余次托卡马克放电，较单一原位锂涂层维持的放电次数高一个数量级，这证明了锂-硅复合涂覆技术的优异性能。     

快速测定硅铁中的硅量

试样以硝酸、氢氟酸溶解，在3mol/L硝酸介质中，加入饱和硝酸钾，使硅酸生成氟硅酸钾沉淀，经过滤，洗涤，除去大部分游离酸，在硝酸钾－乙醇混合液存在下，用氢氧化钠中和残余游离酸，加入沸水使氟硅酸钾沉淀水解，以溴百里香粉蓝－酚红为指示剂，用氢氧化钠标准溶液滴定计算硅量，本方法操作简单，容易掌握，可大大节约分析时间，测定结果令人满意。     

Synthesis and Properties of Perfluoroalkyl Groups Containing Double Four-Ring Spherosilicate (Siloxysilsesquioxane) Precursors

Organically modified cage-like double four-ring spherosilicates have received considerable interest in the construction of nanosized hybrid materials, as well as building units for structural well-defined polymers. This group is extended by perfluoroalkyl ligands containing spherosilicates, synthesized by addition reaction of the octahydridodimethylsiloxyoctasilsesquioxane [H(CH₃)₂Si]₈Si₈O₂₀ and heptadecafluorodecyl methacrylate. The resultant liquid spherosilicate substituted with eight terminal perfluoroalkyl groups was characterized by ²⁹Si and ¹³C NMR spectroscopies and MALDI Time-of-Flight mass spectrometry. Partial substitution of perfluoroalkyl ligands by trimethoxysilyl containing groups provides condensable precursors for the synthesis of hydrophobic and oleophobic materials via the sol-gel process. This new spherosilicate, carrying on average four perfluoroalkyl groups and four trimethoxysilyl groups shows better hydrophobic and oleophobic properties compared with commonly used perfluoroalkyltrialkoxysilanes under identical concentration of perfluoroalkyl chains. In addition a comprehensive literature survey is given on structural well characterized, organically modified cage-like double four-ring spherosilicates.     

Surface SelectiveH/Si CP NMR by NOE Enhancement from Laser Polarized Xenon

The surface proton spin polarization created by the spin-polarization-induced nuclear Overhauser effect from optically polarized xenon can be transferred in a subsequent step by solid-state cross polarization to another nuclear spin species such as²⁹Si. The technique exploits the dipolar interactions of xenon nuclear spins with high γ nuclei such as¹H, and is experimentally simpler than direct polarization transfer from¹²⁹Xe to heteronuclei such as¹³C and²⁹Si.     

Si Micromachined Pinhole and Surrounding Photodiode for Incident Beam Position Sensing and Automatic Alignment

The spatial filter of a Si micromachined pinhole integrated with photodiodes is fabricated. The photodiode cells placed around the center pinhole can detect the relative position between the incident beam spot and the pinhole. The position signal obtained from a two or four cell type photodiode and position sensitive detector show the sensitivity even when the beam spot is near the center pinhole. Combined with the feedback control of the shape memory alloy actuator based on the obtained position signal, the pinhole is aligned automatically.     

A Si nano–micro-wire array on a Si(111) substrate and field emission device applications

A large number of Si wires on Si(111) can be fabricated selectively by the vapor–liquid–solid growth method with a high aspect ratio greater than 100. The diameter of the wire can be controlled from less than a micron to a few hundred microns. We propose a novel smart field electron emission device using silicon nano-wires fabricated by this vapor–liquid–solid growth method, and demonstrate field electron emission with a quite low operation voltage from a gated silicon nano-wire. The threshold voltage is about 13 V, and the value is similar to those for gated carbon-nanotube field emitters. The emission current reaches 10 nA at 15 V gate voltage.     

一种新的半导体材料和器件结构:COS

国际半导体技术发展进程表预期器件的特征尺寸不久将减小到0.1μm以下，SiO2作为MOS器件栅介质遇到不可克服的困难，人们在寻找新的栅介质材料时，提出一种新的结构，称为半导体上的晶态氧化物（COS），最近，COS被用作Si衬底上生长GaAs的过渡层，成为半导体材料和器件发展中一项新的突破，文章对这一结构的进展情况做一简要介绍。     

In-phase step wandering on vicinal Si(1 1 1) surfaces

The step structure transition between a regular step and a bunched step on vicinal Si(1 1 1) surfaces induced by DC is studied by the kinetic Monte Carlo simulation in a terrace-adatom-step-kink (TASK) model. In the TASK model, effective force due to DC is taken into account explicitly on the mass transport of Si adatoms. In the diffusion-limited regime corresponding to the experimental temperature range II, step bunching is induced by step-up force and in-phase wandering of a regular step is formed by step-down force. The in-phase wandering of a regular step is formed by nucleation growth mode and the amplitude of wandering grows with time in proportion to . The period of in-phase wandering decreases as the effective force increases, consistent with the recent experimental results.     

Electroluminescence from Si/SiGe quantum cascade emitters

Intersubband electroluminescence results are presented from Si/SiGe quantum cascade emitters at 3.2 THz and at temperatures up to 150 K. The effect of adding doping into the active quantum wells was studied in addition to reduced barrier widths from previous measurements. While the current through the sample is increased by the addition of doping, the emitted power is reduced through additional free carrier absorption and Coulombic scattering. Free electron laser measurements confirm the intersubband transitions in the quantum wells of the cascade devices and produce non-radiative lifetimes of 20 ps between 4 and 150 K.