SDS/正戊醇/水体系的液晶研究

在 2 5℃测定了十二烷基硫酸钠 (SDS) /正戊醇 /水三元体系的相平衡 ,确定了液晶区域的边界范围。在液晶区域内选取一系列样品点 ,用差示扫描量热法 (DSC)和2 HNMR与液晶照片对照 ,研究了该体系的液晶结构特点。结果表明 :在恒定温度下 ,该体系存在着两个液晶区域 ,并且随含水量的增加 ,液晶结构发生变化。当组成固定时 ,体系的液晶相结构随温度升高也发生变化     

The Region 1 & 3 Broadcasting‐Satellite Service Plan after WRC‐03

The 1977 Broadcasting‐Satellite Service (BSS) Plan for Region 1 & 3 had been widely acknowledged to be out‐of‐date by the late 1980s. Development of digital modulation in the early 1990s provided an opportunity to update the technical provisions of the Plan to make it more economically viable. After a decade of work and three World Radiocommunication Conferences (WRCs), the revision of Region 1 & 3 BSS Plan was finally completed in 2003. The new Plan increased channel assignments from 5 to 10 analog‐equivalent channels for each country in Region 1, and from 4 to 12 channels for each country in Region 3. Yet, despite the increase in capacity, the new Plan is surprisingly similar to the original one in terms of the technical parameters. It is still based on national coverage, and the channel plan, orbital location, orbital spacing, and polarization are also the same. As a result, the new Plan is no more economically viable to implement than the old. To create economically viable BSS systems would most likely require modifications to the assignment in the Plan. Yet, modification procedures were made more difficult to apply after replanning. Less future implementation of BSS networks than would otherwise have occurred can be expected, and an inefficient usage of these frequency bands will likely result. On the other hand, less implemented systems will mean more capacity set aside for future use. This is important for countries that currently do not have satellite operations. In the end, BSS replanning reflects the eternal conflict between efficient usage and guaranteed future access. Copyright © 2005 John Wiley & Sons, Ltd.     

超分子主体化合物在分析化学中的应用研究进展

综述了近年来超分子主体化合物在分析化学领域的应用研究与进展。分别以冠醚、环糊精、杯芳烃、卟啉4类超分子为主体功能化合物的研究进行了详细的评述，并对这几类主体化合物在分析化学中的应用研究进行了展望。     

中间馏分油型加氢裂化催化剂用沸石的研究

通过水热处理法制备了3个不同脱铝深度的改性Y沸石，再经浸渍法制成中间馏分油型加氢裂化催化剂，在200mL小型加氢裂化装置上进行了催化性能评价。试验结果表明，除了沸石的酸性外，其孔结构和比表面积对催化剂的活性、中间馏分油选择性和液体收率都有很大的影响，为最大幅度提高催化剂的中间馏分油选择性并保持较好活性，要求沸石具有较低的酸量、较高的比表面积和较多的二次孔及适量的L酸量。     

一种探测二维电磁目标的新方法

电磁目标的探测对通信而言有着十分重要的意义。本文描述一种收敛迅速、结果准确、抗强随机噪声的探测二维电磁目标的新方法。首先从体等效原理出发得到一个积分方程组，此方程组可求解散射问题。随后，对此方程组求变分，变形后得到散射场变化与介电参数变化之间关系的矩阵方程，即反演方程。文中列举了几个例子，通过数值实验结果证明本法收敛速度快、反演精度高、适应复杂目标的能力强，能抗强随机噪声干扰     

3D optical interconnects for high-speed interchip and interboardcommunications

Metal-based communications between subsystems and chips has become the limiting factor in high-speed computing. Maturing optics-based technologies offer advantages that may unplug this bottleneck. Optical interconnects offer high-speed computers key advantages over metal interconnects. These include (1) high spatial and temporal bandwidths, (2) high-speed transmission, (3) low crosstalk independent of data rates, and (4) high interconnect densities. Although faster device switching speeds will eventually be necessary for future massively parallel computing systems, the deciding factor in determining system performance and cost will be subsystem communications rather than device speed. Free-space optical interconnects, by virtue of their inherent parallelism, high data bandwidth, small size and power requirement, and relative freedom from mutual interference of signals, already show great promise in replacing metal interconnects to solve communication problems     

新型超微晶软磁合金FePCCuMoSi微观结构缺陷的正电子湮没研究

用正电子湮没方法研究了新型超微晶软磁合金的微观结构缺陷，样品选用的是在不同温度下退火的Ｆｅ８１Ｐ１２Ｃ３Ｃｕ１Ｍｏ０．５Ｓｉ２．５合金，结果表明，合金的微观结构构陷大小，密度随退火温度有规律地变化，这种现象可能与非晶的晶化过程有关。     

A novel proof of the Souriau-Frame-Faddeev algorithm

A simple and elegant proof is given for a recurrence relation that computes the coefficients of the characteristic polynomial of a linear system used in the Souriau-Frame-Faddeev algorithm     

Matrix unit cell scheduler (MUCS) for input-buffered ATM switches

This paper presents a novel matrix unit cell scheduler (MUCS) for input-buffered asynchronous transfer mode (ATM) switches. The MUCS concept originates from a heuristic strategy that leads to an optimal solution for cell scheduling. Numerical analysis indicates that input-buffered ATM switches scheduled by MUCS can utilize nearly 100% of the available link bandwidth. A transistor-level MUCS circuit has been designed and verified using HSPICE. The circuit features a regular structure, minimal interconnects, and a low transistor count. HSPICE simulation indicates that using 2-μm CMOS technology, the MUCS circuit can operate at clock frequency of 100 MHz     

AFA 3G燃料棒下端塞电子束焊产生气胀的分析

宜宾核燃料元件厂在AFA 3G燃料棒首次产品合格性鉴定中发现，大批下端环缝焊产生了气胀的焊接缺陷。本文分析了产生气胀缺陷的原因，并介绍了针对其原因进行的各种试验。结果表明，改变焊接参数，即提高焊接速度和适当控制电子束流强度，是解决燃料棒焊接气胀缺陷的最好途径。