一种实现高性能TCM的卷积编码器结构

本文提出了一种用于网格编码调制(TCM)技术的卷积编码器结构,并在三种不同的信号分配约束条件下对具有最大自由欧几里德距离的TCM码进行了搜索,结果表明:当状态数目较少时,Ungerboeck建议的规则是获得好码的前提条件,当状态增多时,可能存在有其它的信号分配形式达到最好的性能。     

广义沃尔什函数的构造与生成

本文对沃尔什函数的对称复制和平移复制概念进行了推广,提出了用循环右移复制和广义平移复制方式来构造或产生广义沃尔什函数(Chrestenson函数)的方法     

分子电子结构的造型系统

本文叙述了一个实用的分子电子结构的造型系统,用来辅助研究分子内部的微观状态(如电子波函数、电荷密度、静电势和空间的分布等)。该造型系统将在VAX-11/780上得到的分子轨道计算结果在微机仿真图形工作站用三维网格图和云雾状点图表示出来。它为研究分子内部电子结构以及新材料的设计提供了有效的辅助工具。本文以抗肿瘤药物分子为研究对象,取得了初步结果。     

单片式3.6μs pn结二极管存储相关器/卷积器

本文报道一种单片式金属氧化锌、二氧化硅(MZOS)结构存储相关器。在我国首次实现将参考信号“写入”(存储)二极管阵列中,然后用读信号将其“读出”,该器件也可用作卷积器。本文简叙了器件设计、结构、制作方法、工作模式和性能参数。     

高铜超纯铁素体不锈钢热变形行为研究

为研究高铜超纯铁素体不锈钢(21Cr-1.5Cu)热加工过程中变形温度和应变率对热变形行为影响,在变形温度为950、1000、1050、1100、1150、1200℃,应变率为0.01、0.1、1、10 s-1条件下对其进行热变形试验.结果表明:试验钢热变形方程为ε.=5.81×1013sinh(ασ)4.6825exp(-323000/RT).热加工图中流变失稳区主要有3处:变形温度为950～1060℃,应变率为0.15～1.1 s-1;变形温度为1050～1080℃,应变率为3～10 s-1;变形温度为1130～1180℃,应变率为1～10 s-1.分析可知,变形温度为1075～1200℃,变形率为0.01～0.1 s-1最适合热加工,能耗率达40％以上,且应变量增加,失稳区增大.     

横向过载对固体火箭发动机推进剂点火建压过程的影响

大过载下固体火箭燃烧与流动状态的剧烈变化会导致内弹道出现异常,严重时可能会引起发动机点火失败。为研究横向过载时点火内弹道特性,建立囊括流场惯性过载效应、过载燃烧效应和侵蚀燃烧效应的点火模型。对不同横向过载下燃烧室压力和侵蚀与过载效应燃速增速占比进行计算,并给出了推进剂火焰传播速度与升压速率的关系。结果表明：正向过载下压力峰值增加,负向过载下压力峰值降低;正向过载下,推进剂前段主要由过载效应影响,后段主要由侵蚀效应影响;正向过载加剧下游侵蚀效应,而负向过载对推进剂的燃烧起削弱作用,但程度较弱、持续时间较短;火焰传播速度峰值时刻、推进剂表面首次全部点燃时刻和升压速率峰值点时刻几乎一致,工程上可以用实验中获得的升压速率分析推进剂表面燃烧状况。     

汽油典型烃分子氧化生胶机理的分子模拟

为深入认识汽油在使用过程中氧化生胶的反应机理,选取汽油中相同碳数的典型烃分子作为模型化合物,采用基于密度泛函理论的量子化学从头计算方法,建立了不同结构的汽油分子通过氧化链式自由基反应生成相对分子质量较大、极性较高的沉积物分子的反应网络。通过对比不同反应路径的反应能垒大小,得出容易氧化生胶的汽油烃分子的结构特点以及贡献生成沉积物的关键控速步骤和关键中间体,从而为抑制该氧化生胶过程提出关键措施。结果表明,汽油分子结构中存在双键α位C-H、叔位C-H或苯基α位C-H时,容易引发链式自由基反应,但能否继续向沉积物的反应方向进行取决于相对分子质量增大后的产物中是否仍然存在双键α位C-H、叔位C-H、苯基α位C-H或者C=O这种使得相邻C-H键变弱的吸电子基团。另外,在氧化生胶反应过程中,氢过氧化物（ROOH）和过氧自由基（ROO·）是最关键的2个中间体,抑制氧化生胶反应的关键在于清除它们。     

Polyoxometalate-based silica-supported ionic liquids for heterogeneous oxidative desulfurization in fuels

With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman,UV–Vis, wide-angle XRD and N_2 adsorption–desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions.The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone.     

Study of the numerical simulation of tight sandstone gas molecular diffusion based on digital core technology

Diffusion is an important mass transfer mode of tight sandstone gas. Since nano-pores are extensively developed in the interior of tight sandstone, a considerable body of research indicates that the type of diffusion is mainly molecular diffusion based on Fick’s law. However, accurate modeling and understanding the physics of gas transport phenomena in nanoporous media is still a challenge for researchers and traditional investigation (analytical and experimental methods) have many limitations in studying the generic behavior. In this paper, we used Nano-CT to observe the pore structures of samples of the tight sandstone of western of Sichuan. Combined with advanced image processing technology, threedimensional distributions of the nanometer-sized pores were reconstructed and a tight sandstone digital core model was built, as well the pore structure parameters were analyzed quantitatively. Based on the digital core model, the diffusion process of methane molecules from a higher concentration area to a lower concentration area was simulated by a finite volume method. Finally, the reservoir’s concentration evolution was visualized and the intrinsic molecular diffusivity tensor which reflects the diffusion capabilities of this rock was calculated. Through comparisons, we found that our calculated result was in good agreement with other empirical results. This study provides a new research method for tight sandstone digital rock physics. It is a foundation for future tight sandstone gas percolation theory and numerical simulation research.     

钯合金扩散室微束等离子焊接

针对钯合金扩散室的结构及焊接特点,研究了钯膜与不锈钢的微束等离子焊接工艺,通过设计合理的夹具及在钯膜表面镀镍的方法得到了气密性优良的焊接件。产品的漏率小于1×10^-9 Pa.m³/s,满足扩散室低泄漏率的使用要求。