导弹水下潜射过程的流体—固体耦合仿真

导弹潜射是集高速流动、冲击、结构响应于一体的流体—固体—气体三态非线性耦合复杂过程,是决定潜射导弹发射成败的关键环节。本文应用LS-DYNA显式程序建立了三种包含水体、空气、导弹、发射井和筒盖的多物质耦合ALE网格模型,使用罚函数流体—固体耦合方法对导弹水下无攻角潜射过程进行了数值模拟,给出了弹体质心的轴向加速度、轴向流体阻力及阻力系数、空泡区压力分布。仿真结果表明,模型2的仿真过程与实际导弹潜射过程最为相符。同时总结介绍了LS-DYNA程序中流体—固体耦合计算的相关设定原则和方法。本文可为潜射导弹的水动力载荷设计和数值仿真提供有益的参考。

导弹潜射过程的流体动力载荷仿真

导弹潜射过程是流-固-气三态耦合的非定常复杂过程,更是决定导弹发射成败的关键．本研究运用ANSYS／LS-DYNA显式程序对导弹的水下发射过程进行了模拟,以期为导弹设计提供有益的技术参考．文中流体模型采用多物质ALE单元,使用罚函数流-固耦合方法进行导弹潜射过程仿真,流体初始静水压力应用动力学平衡方法进行初始化,最终仿真得到导弹的流体阻力及压力分布时程曲线．基于仿真所得数据,对导弹流体阻力系数进行了计算和讨论,为导弹的流体阻力系数提供了一种全新的校核方法．

纳米半导体技术

本书介绍了纳米半导体材料的定义、性质及其在未来信息技术中的地位的同时，主要介绍了纳米半导体材料制备的方法和共性关键技术，几种常用的纳米半导体材料的评价技术和应变自组装半导体量子点(线)的尺寸、密度分布、形貌、组分及结构特性的实验研究，纳米半导体材料的电子结构、光学和电学性质，基于子带跃迁的量子级联激光器的工作原理、特性和它的发展现状及其应用前景分析，最后重点介绍了纳米半导体器件及应用。本书适合于从事或对纳米半导体科学技术有兴趣的科研工作者、教师、研究生、本科生和工程技术人员阅读，有些章节可作为科普读物。

The effect of low temperature GaAs nucleation on the growth of GaN on Silicon (001) during MOVPE process

High quality cubic GaN was grown on Silicon (001) by metalorganic vapor phase epitaxy (MOVPE) using a GaAs nucleation layer grown at low temperature. The influence of various nucleation conditions on the GaN epilayers' quality was investigated. We found that the GaAs nucleation layer grown by atomic layer epitaxy (ALE) could improve the quality of GaN films by depressing the formation of mixed phase. Photoluminescence (PL) and X-ray diffraction were used to characterize the properties of GaN epilayers. High quality GaN epilayers with PL full width at half maximum (FWHM) of 130meV at room temperature and X-ray FWHM of 70 arc-min were obtained by using 10-20nm GaAs nucleation layer grown by ALE.

Poly(vinyl methyl ether) poly(methyl methacrylate) blends using diblock copolymer of styrene and methyl methacrylate as compatibilizer

Blends of poly(vinyl methyl ether) (PVME) and poly(methyl methacrylate) (PMMA) compatibilized by poly(styrene-block-methyl methacrylate) (P(S-b-MMA)) ale studied by FT-IR, DSC, excimer fluorescence spectrometry, and scanning electron microscopy (SEM). In FT-IR measurement the ratio of absorption intensity at 1107 cm(-1) to that at 1085 cm(-1) (I-1107/I-1085) reaches a minimum at about 10wt% block copolymer content. DSC results show that the glass transition temperature of PVME in the blends has a maximum at 10 wt% copolymer content. In plots of the ratio of excimer-to-monomer fluorescence emission intensities (I-E/I-M) VS block copolymer content, I-E/I-M increases rapidly above 10%. Ail these phenomena show that PS block chains penetrate into PVME: domains on addition of block copolymer. Above 10% copolymer content, block copolymer chains tend to form micelles in bulk phase.

基于动态混合网格的AUV水下发射与对接数值仿真研究

实现AUV水下发射和对接是解决AUV水下能源补充，水下数据交换和故障检测，实现AUV整个作业过程完全自主的必要前提。而AUV水下发射和对接运动的流场为多个物体运动的流场耦合叠加，对AUV的运动影响不同于无界流场中的单体运动，因此非常有必要研究多体相对运动的绕流场对AUV运动的影响，以实现AUV水下发射和对接的高精度控制，最终实现AUV水下发射和对接工程。 本文为获得AUV水下发射和对接过程数值模拟，针对水下单体、多体的三维大位移运动边界数值仿真问题提出了一种基于动态混合网格数值仿真的方法。主要解决了关键的三个方面问题：1)如何根据流场的特性划分网格拓扑结构，建立适合物体运动的网格；2)如何适应移动边界运动的任意性，建立相应的控制方程，并构建相应的运动区域方法和网格更新方法；3)如何实现移动网格的加速求解并保持计算精度。本文的主要研究内容为： 1) 针对复杂单一域提出一种基于八叉树、Delaunay三角化、层面推进法和前沿推进法的三维混合网格生成方法；对复杂多域提出块混合网格生成方法。数值结果表明，采用本文提出的这两种网格划分方法能适应复杂区域的网格划分，同时能满足流场分布特性，减少网格数量，提高网格划分的质量，提高数值求解精度。 2) 从提高ALE描述的控制方程计算精度方面，提出了三维动态混合网格方 法、改进动态混合网格方法和动态层混合网格方法分别适用于不同运动模式下的网格运动更新。这样不仅能描述任意形式的物体运动，而且能遵守ALE描述控制方程的守恒性，同时提高网格更新的速度，网格更新后的质量和数值求解的精度。 3) 针对多体非定常数值求解耗时，本文提出了动态混合网格并行计算模型，采用基于区域分解的分块耦合并行算法来加速数值求解速度。在不损失计算精度的前提下获得了很高的并行计算加速比。 4) 为了验证移动网格法数值求解的精度，本文首先对单个复杂形状的AUV进行了非定常直航和非定常回转运动的运动边界数值仿真，并用试验和定常求解结果和非定常附加动量源方法验证了移动网格法数值求解的精度。 5) 本文将混合网格方法、移动网格方法和并行计算方法应用到了AUV从发射管发射和对接发射管两个过程的三维大位移运动边界数值仿真中，并用理论值和定常结果验证了数值求解的精度，得到AUV发射过程和对接过程的流场水动力特性，并通过理论和数值试验，提出AUV水下发射和对接方案。

精神分裂症患者及其未患病一级亲属的面孔情绪知觉研究

Schizophrenia is a heritable disorder. However, molecular genetics and related research area have not unmasked the nature and mechanisms of this disorder. Therefore, many researchers begin to explore the pathology mechanism from other approaches. High-risk study is one of the promising approaches. In this study, we mainly focused on facial emotion perception in schizophrenia and their non-psychotic first-degree relatives, and attempted to explore whether facial emotion perception is the potential biological marker of schizophrenia. This dissertation comprises 4 studies. In the first study, we conducted a meta-analysis on behavioral data of facial emotion perception in schizophrenia. Our findings showed that patients demonstrated general deficits in both facial emotion perception and facial processing tasks. In the second study, sixty-nine patients with schizophrenia and 56 of their first-degree relatives (33 parents and 23 siblings), and 92 healthy controls (67 younger and 25 older healthy controls) completed a set of facial emotion perception tasks. The results validated that patients with schizophrenia displayed general deficits in facial emotion perception. Study two also demonstrated that siblings of patients performed equally well compared to the corresponding younger healthy controls in all the facial emotion perception tasks, while the parents of patients behaved significantly worse than the corresponding older healthy controls in the composite index of facial emotion perception tasks. The results suggest that relatives of patients display more severely declining in facial emotion perception with the increasing of age. In the third study, we used an automated voxel-wise technique, activation likelihood estimation (ALE) to provide an objective, quantitative evaluation of facial emotion processing in schizophrenia. Our findings demonstrated a marked under-recruitment of the amygdala, accompanied by a substantial limitation in activation in schizophrenia throughout a ventral temporal-basal ganglia-prefrontal cortex ‘social-brain’ system may be central to the difficulties patients experience when processing facial emotion. In the last study, we did an fMRI study about facial emotion perception in 12 patients with schizophrenia, 12 non-psychotic siblings of patients and 12 healthy controls. The results suggest that siblings of patients demonstrate abnormal activation in a variety of brain areas, including prefrontal gyrus, insula, parahippocampal gyrus and superior temporal gyrus. Taken together, the current findings suggest facial emotion perception may be a potential biological marker of schizophrenia.