各种视听会议终端的互通

本文介绍基于Ｈ．３２０．Ｈ．３２１．Ｈ．３２２，Ｈ．３２３，Ｈ．３１０等Ｈ系列建议的视听会议终端之间的互通以及各建议适用的网络互连使用的网关的功能和结构。     

低相噪,低杂波数字锁相环路滤波器的设计

较详细地分析数字锁相频率合成器的相位噪声，着重用控制论方法对低相噪、低杂波锁相环的环路滤波器进行设计，并用某Ｓ波段频率合成器的实验结果进行了验证。     

钼还原过程相变化研究

采用钼酸铵直接氢还原及钼酸铵先焙解然后再分段氢还原两种不同的还原方法进行了钼粉还原。通过Ｘ射线衍射方法分析了两种工艺还原过程中的反应序列及相变化规律，并讨论了不稳定相Ｍｏ４Ｏ１１对于钼粉还原过程的影响。     

Effects of thymectomy and glucocorticoid therapy on peripheral lymphocytes in myasthenia gravis

Clinical manifestations and peripheral blood lymphocyte subset changes were studied in patients with myasthenia gravis (MG) to elucidate the mechanism of clinical improvement following treatment, with thymectomy (Tx) or glucocorticoid (GC) therapy. The changes found were: 1. There was a significant increase in percentages of CD3+, CD29+ CD4+ cells and CD4/CD8 ratio and a significant decrease in percentages of CD8+ and CD16,56+ cells in patients who had never been treated with any immune therapy. 2. After Tx or GC therapy, CD3+ and CD4+, CD29+ cells were decreased, but the number CD19+ and CD16, CD56 cells did not change. 3. Tx had a special effect on CD8+ cells. In most of the patients who showed clinical improvement after Tx, CD8+ cells were increased and CD4/CD8 ratio wad decreased. 4. Anti-acetylcholine receptor (AChRAb) titers were markedly decreased after GC therapy. These results indicate that there were obvious abnormalities in cell-mediated immunity in addition to those in humoral immunity in myasthenia gravis. These abnormalities tended to be normalized after Tx or GC therapy.     

含微量元素铜焊锡丝的研制

在６０／４０的锡铅焊料中加入０．２％左右的铜，凝固后具有均匀细小的共晶组织，其熔点为１８３℃，焊点强度和扩展率均高于未加铜的６０／４０锡铅焊料，并且含铜的锡铅焊料在焊接时，对铜烙铁头和微细铜线了小的熔蚀性。     

无线数据通信网发展趋势

无线数据通信具有两大发展趋势，即低速的广域移动数据网及高速的局域无线数据网。本文介绍了其技术特点、应用情况和市场前景，分析了无线数据通信传输技术、网络结构和媒质接入控制等问题。     

交联型聚醚聚氨酯的表征、力学性能及其碱金属盐络合物的导电性能

采用三羟甲基丙烷（ＴＭＰ）作交联剂与聚乙二醇（ＰＥＯ－１５４０）和甲苯二异氰酸酯（ＴＤＩ）反应，得到了具有较好力学性能的交联型聚醚聚氨酯（ＰＥＵ），该聚合物与ＬｉＣｌＯ４的结合物具有较高的室温电导率（σ３０℃＝１．８７×１０￣（－４）Ｓ／ｃｍ）。采用全反射红外光谱（ＡＴＲ－ＩＲ）对聚合物的结构进行了表征。对聚合物的组成、不同ＴＤＩ类型及络合盐浓度对聚合物力学性能及其络合物电导率的影响进行了探讨。低度交联聚合物的络合物，其电导率与温度的关系符合建立在自由体积理论上的ＶＴＦ方程，表明络合物中离子的传导主要是在无定形区域进行，与自由体积有关。     

Characterization of mutated transforming growth factor-beta s which possess unique biological properties

Transforming growth factor-beta (TGF-beta) is a potent regulator of cell growth and differentiation. On the basis of the crystal structure of TGF-beta 2, we have designed and synthesized two mutant TGF-beta s, TGF-beta 1 (71 Trp) and TGF-beta 1 (delta 69-73). Although both of these molecules inhibited the growth of Mv1Lu mink lung epithelial cells and LS1034 colorectal cancer cells, which are affected equally by TGF-beta 1 and TGF-beta 2, TGF-beta 1 (delta 69-73) was much less potent than TGF-beta 1 or TGF-beta 1 (71 Trp) at inhibiting the growth of LS513 colorectal cancer cells which are growth-inhibited by TGF-beta 1 but not TGF-beta 2. Both TGF-beta 1 (71 Trp) and TGF-beta 1 (delta 69-73) increased levels of mRNAs for fibronectin and plasminogen activator inhibitor with Mv1Lu cells, whereas only TGF-beta 1 (71 Trp) and not TGF-beta 1 (delta 69-73) up-regulated the mRNA level of carcinoembryonic antigen in LS513 cells. The expression level of carcinoembryonic antigen mRNA in LS1034 cells was not altered by either wild-type or mutant TGF-beta s. Receptor labeling experiments demonstrated that TGF-beta 1 (71 Trp) bound with high affinity to the cell-surface receptors of Mv1Lu, LS1034, and LS513 cells while TGF-beta 1 (delta 69-73) bound effectively to the receptors of Mv1Lu and LS1034 cells but much less to the receptors on LS513 cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

DCS的评价与选择

本文综述了ＤＣＳ（集散控制系统）三代产品的总体水平评价，介绍了ＤＣＳ的总体性能、评价指标和它的选择准则。     

Design model and guidelines for n-well guard ring in epitaxial CMOS

This work reports the development of design model for n-well guard rings in a CMOS process utilizing a low-doped epitaxial layer on a highly doped substrate. The validity of the model has been judged by a wide range of experimental data measured from the fabricated n-well guard ring structures with guard ring width as parameter. From the model developed, guidelines have been drawn to minimize the guard ring width while critically suppressing the amount of electrons escaping from the guard ring