自适应抗干扰系统在引信中的应用

为了提高无线电引信的抗干扰性能,研究以自适应天线技术为基础的引信抗干扰系统.根据信号与干扰的具体环境,灵活地控制天线的参数,自动调节方向图,使其零点自适应地对准干扰方向,以实现在空间上对信号的最佳接收和对干扰的有效抑制.     

Effects of compressive and tensile stress on the growth mode of epitaxial oxide films

Oxide films were deposited on different substrates by laser molecular beam epitaxy. Reflection high-energy electron diffraction was performed to in situ investigate the change of growth mode and the lattice relaxation during the growth. An asymmetrical phenomenon was found in the two kinds of strain states, compressive stress and tensile stress of heterostructures with different lattice mismatch. In the case of BaTiO₃/SrTiO₃ (2.2%), 2D layer-by-layer growth mode without lattice relaxation can be maintained for a longer period for BTO films on STO with compressive stress, comparing to STO films on BTO with tensile stress. When MgO films were deposited on SrTiO₃ with a large mismatch of 7.8%, compressive stress leads to rapid lattice relaxation with a very thin wet layer, and 3D strained island were observed. As a comparison, SrTiO₃ films on MgO with tensile stress were configured. No RHEED patterns can be observed duo to a large tensile stress.     

氩等离子体辐照反相乳液接枝改性涤纶织物的研究

首次提出了在等离子体辐照后再用反相乳液接枝改性涤纶织物的新方法,探讨了接枝颗粒特征以及织物各项物理力学性能.接枝织物的结构及性能的测试结果表明:接枝物的尺寸远小于纤维的直径,在提高织物吸湿性的同时,对织物透气性能和强力等无明显影响;实验也证实了乳液中未接枝单体可以再次聚合.     

两种塑料纸芯管结构与性能比较分析

测试与分析了两种塑料管材的拉伸与弯曲性能、热变形温度、结晶性和化学组成,分析结果表明:管材B较管材A具有更高模量与热变形温度,但管材B较高的分子量与较小的分子量分布抑制管材产品内在的均匀性,且管材B中的α晶在高温下向β晶的转变可能会影响管材长期使用性能.     

无线局域网的安全解决方案

本文描述了无线局城网中的认证和密钥管理协议,CCMP认证加密协议。IEEE 802.11依赖于IEEE 802.1x 来支持认证和密钥管理服务,更进一步的,四次握手协议用来建立分组传输的数据加密密钥。IEEE 802.11i也定义了认证者更新一个组暂时密钥(GTK)给请求者的组密钥握手,这样请求者可以接收广播消息。     

Synthesis and Characterizations of Triphenylamine End-Functionalized Polymers via Reversible Addition-Fragmentation Chain Transfer Polymerization

A novel reversible addition-fragmentation chain transfer (RAFT) reagent bearing triphenylamine (TPA) group, 4-diphenylamino-dithiobenzoic acid benzyl ester (DDABE), was designed and synthesized. It was used in the RAFT polymerizations of styrene (St) and methyl acrylate (MA) to prepare end-functionalized polymers. The results of the polymerization showed that the RAFT polymerizations could be well controlled using DDABE as the RAFT agent. Number-average molecular weight (M_n,GPC) increased linearly with monomer conversion, and molecular weight distributions were relatively narrow (PDI< 1.50). The results of chain-extension reaction, ¹H NMR spectra and UV/Vis spectra confirmed that most of the polymers chains were end-capped by the functional triphenylamine (TPA) groups. The effect of feed molar ratios of St/DDABE/AIBN on polymerization was investigated.     

熟悉而又陌生

《Frame》总第46期向读者展示了许多有意思的想法和创意的细节下面是从中摘选出来的设计和空间方案他们都运用到了我们身边很熟悉的元素，在这里“腐朽”一下化神奇了。[编者按]     

小波包变换压缩与地震数据处理

探讨了地震数据经小波包变换压缩后对后续处理过程的影响,以及经过某些处理后的数据会对小波包变换压缩产生什么影响等问题。将小波包变换压缩地震数据的结果与快速傅里叶变换压缩地震数据的结果进行了对比,其结果表明:应用小波包变换压缩地震数据,有效信号的损失非常小,压缩比大于快速傅里叶变换的压缩比。在大批量地震数据处理中可以使用小波包变换压缩地震数据。     

提高常规色谱分析的速度,应对新法规的需求

珀金埃尔默公司新推出的Clarus 600型GC和GCMS采用全新柱温箱设计，能够缩短每次分析循环的时间，在有限的时间内可以完成更多的分析测试，从而提高分析效率和仪器的投资回报率。特别适合于需要大批量分析检测的实验室和需要测定挥发性有机物的分析工作。     

蓄热式均热炉生产中存在问题的分析及解决方案

介绍了高温空气燃烧技术在均热炉上的应用情况，对应用中出现的问题进行了分析，并提出了解决方案。