分步法高速沉积微晶硅薄膜

为提高微晶硅薄膜的纵向结晶性能, 在甚高频等离子体增强化学气相沉积技术的基础上, 采用过渡参数缓变和两步法相结合的方法在普通玻璃衬底上高速沉积薄膜. 当功率密度为2.1 W/cm², 硅烷浓度在6%和9.6%之间变化时, 从薄膜方向和玻璃方向测算的Raman晶化率的差异维持在2%以内. 硅烷浓度为9.6%时, 薄膜沉积速率可达3.43 nm/s, 从薄膜方向和玻璃方向测算的Raman晶化率分别为50%和48%, 差异的相对值仅为4.0%. 合理控制过渡阶段的参数变化, 可使两个方向的Raman晶化率差值下降到一个百分点. 表明采用新方法制备薄膜, 不仅可以抑制非晶孵化层的形成, 改善微晶硅薄膜的纵向结构, 还为制备优质薄膜提供了较宽的参数变化空间. 关键词： 微晶硅薄膜 非晶孵化层 高速沉积 甚高频等离子体增强化学气相沉积     

112 Gbit/s信号混传多种速率信号的非线性效应影响

主要研究在波长间隔50GHz的密集波分复用系统中,112Gbit/s偏分复用差分四相移键控信号在不同速率的相邻信道影响下经过长距离传输后的非线性容忍度。实验结果表明,112Gbit/s信号结合43Gbit/s信号或者10Gbit/s信号传输时系统得到较好的非线性容忍度,验证了在严重的非线性效应存在的情况下同步传输系统的可行性。     

快速床动力学统一模型Ⅱ:上部稀相与下部浓相固含率的预报

在前文建立的分相共存快速床动力学模型的基础上,对分相模型中存在颗粒团聚物时的上升稀相进行了受力分析。以有限直径提升管中颗粒终端速度的修正,导出了上升稀相受力关于等效管径与浓稀相滑移速度的修正表达式。将本模型预报的上部稀相固含率与已有的实验数据经验关联式进行了对比,并根据所得结果初步优化了模型参数(k=8,n=6)。进而,根据所得模型参数计算了下部浓相固含率随曳力函数f(ε)的变化规律;与李佑楚经验关联式相比,同样具有合理的一致性。本文工作进一步验证了快速床动力学统一模型的整体合理性。     

结构层热扩散系数对超薄涂层热力性能的影响

将非傅立叶热传导模型(用于超薄热涂层)与傅立叶热传导模型(用于结构层)相结合 求解温度场,运用有限元法求解热涂层热应力和裂纹驱动力,并分析结构层材料热扩散系数 的变化对热涂层的热力学性能(温度场、应力场和断裂性能)的影响. 研究表明,结构层材 料性能变化对温度场的影响主要表现在热冲击后期,对热应力和裂纹尖端驱动力后期的变化 也有一定的影响.     

Effect of the liquid-like ionic structure on the electron–ion energy relaxation timescales in dense plasmas

In a recent publication [J. Daligault, D. Mozyrsky, Phys. Rev. E 75 (2007) 026402], we derived a general expression for the electron–ion energy relaxation rate in plasmas which, as a result of the small electron–ion mass ratio, expresses the relaxation rate in terms of the low-frequency electronic density fluctuations. Here we propose a practical model for the electronic density fluctuations in dense plasmas and apply this model to the calculation of the electron–ion energy relaxation rate. We find that the rate is only scarcely affected by the underlying liquid-like ionic disorder typical of dense matter. Relaxation rates obtained are systematically slightly larger than those predicted by the Fermi Golden Rule formula, in contradiction with the coupled-modes' theory that predicts values an order of magnitude lower. We also find that the discontinuity of the rate at melting is tiny, in contrast with the sharp increase of the electrical conductivity.     

Scheme for Implementing Quantum Dense Coding and Teleportation with Tripartite Entangled State in Cavity QED

In this paper, we present a peculiar tripartite entangled state that is inequivalent to both the GHZ state and the W state, and then propose to implement efficient quantum information processing such as quantum dense coding and teleportation with this entangled state in cavity QED. In this scheme the atoms interact with a highly detuned cavity field with the assistance of a strong classical driven field. It does not require the transfer of quantum information between the atomic system and the cavity, and then our scheme is insensitive to both the cavity decay and the thermal field.     

The Influence of the Renormalization Condition to the Equation of State of the Nuclear Matter

In the relativistic σ-ω model, the influences of the parameters b, c, d in the potential U(σ)=(1/2!)bσ²+(1/3!)cσ³+ (1/4!)dσ⁴ to the incompressibility, effective mass and binding energy of the nuclear matter are studied in detail. The calculation of equation of state of nuclear matter shows that the values of b, c, d depend on the renormalization condition, we also find that a soft equation of state of nuclear matter can be obtained in a suitable renormalization condition, and the experimental incompressibility coefficient can be reproduced. These results are also used to study the thermal properties of hot Δ-resonant nuclear matter.     

极低风速下热线测量的方向特性

在风速为6～30m/s的范围内,许多研究表明可近似认为热线探针的偏角因子K1和倾角因子K2不随风速变化,倾角θ对K1及偏角ψ对K2也近似认为没有影响,一般采用k1≈0.2,K2≈1.02.然而在极低风速下,特别是1m/s以下,由于热线的传热机理发生变化,所以K1和K2也出现了显著的变化.本文对单丝探针和双丝探针方向特性进行了探讨性的研究,实验表明,风速小于3m/s时,K1和K2随速度发生变化,且θ对K1以及ψ对K2都有影响.当取ψ和θ为90°时,K1和K2在整个角度范围内计算速度的误差较小.     

HOW GOOD IS A DENSE SHOP SCHEDULE?

In this paper, we study a class of simple and easy-to-construct shop schedules, known as dense schedules. We present tight bounds on the maximum deviation in makespan of dense flow-shop and job-shop schedules from their optimal ones. For dense open-shop schedules, we do the same for the special case of four machines and thus add a stronger supporting case for proving a standing conjecture. Support for the research by the first author is provided by the Management Research Fellowship of the ESRC (Economic & Social Research Council) of U.K., and this research is also partially supported by the National Natural Science Foundation of China.     

Wavelet-based Preconditioners for Dense Matrices with Non-Smooth Local Features

We present algorithms for the detection of local non-smooth features within a dense matrix and show how, by isolating such features, we are able to use wavelet compression to design preconditioners for the corresponding dense linear system. We illustrate our approach with examples from the solution of elastohydrodynamic lubrication problems and boundary integral equations.This revised version was published online in October 2005 with corrections to the Cover Date.