无线收、发信机的设计

主要讲述移动通信中收、发信机的工作原理、基本结构和组成.在给出收、发信机原理框图的同时,着重分析了锁相环路的设计.     

α-蒎烯催化加氢反应的研究

以FYX - 2G型高压搅拌釜为加氢反应器 ,测定了在不同搅拌器型式和搅拌转速下高压釜的持气量和反应效果 ,认识到α 蒎烯催化加氢是外扩散控制的反应 ,当搅拌转速为 6 0 0r/min时 ,基本上能消除外扩散的影响。考察了Raney镍和Pd/C催化剂、反应温度在 35 3～ 499K ,压力在 4 0～ 10MPa的条件下对α 蒎烯加氢转化率和选择性的影响 ,结果表明Raney镍更适宜于α 蒎烯催化加氢 ,其转化率随温度、压力增加而提高 ,但选择性下降。采用温度 35 3～ 433K、压力 4 0～ 7 0MPa的操作序列 ,克服了α 蒎烯加氢转化率与选择性互为逆向的缺点 ,缩短了反应时间 ,制得了顺反比高达 18 2∶1的蒎烷 ,并且发现加氢反应从温度 433K开始有副产物对烷生成 ,当温度超过 45 6K时 ,加氢过程还出现飞温现象。     

NBR/PP热塑性弹性体研究进展

阐述了NBR／PP共混热塑性弹性体动态硫化胶的国内外研究进展、微观相态结构、性能、应用及展望。     

Trace elements in particles of motor vehicle exhaust in Shanghai

A nuclear microprobe with high spatial resolution and high analytical sensitivity was applied to analyze trace elements,especially lead,in vehicle exhaust of Shanghai city.The result shows that the chemical composition and its corresponding x-ray relative intensity are different among different vehicle exhausts.There are many kinds of metal elements in particles of vehicle exhaust.most are harmful to people,such as Ti,Cr,Mn,Pb,etc.We found that the lead concentration was 6820μg/g and the bromine concentration was 5300μg/g in the exhaust from Santana using leaded gasoline(SULG).which is higher than any other kinds of vehicle exhausts.We have also detected the minimum lead in the particles of unleaded gasoline and its content varies from one to another.Its mean concentration was 450μg/g and the highest reached 6210μg/g.The unleaded gasoline‘s Pb existed in the whole particle while the leaded gasoline‘s enriched in the surface of the particle and was more harmful to the human beings.     

河道治理工程水土保持设计

河道治理工程的实施会对工程区域内的自然生态环境和水土保持带来负面影响。以独流减河左堤治理工程为例 ,分析工程建设中可能造成的水土流失影响 ,从工程和生物两方面提出水土保持的防治措施 ,并对其投资进行了初步估算。     

数字电视传输流的实时码率变换系统

数字视频压缩后通常是打包成传输流的形式进行传送，年个传输流有其固定的发送码率，在某些应用场合，比如信道调制前端，需要对输入传输流码率进行改变以适应该信道要求，描述了一种全硬件实现，双路输出，实时，节目可选择的码率变换系统的原理及具体实现。     

舰船水声隐身技术(二)

本文探讨了水声隐身性能对舰船战技术性能的影响 ,舰船水噪声的主要噪声源、水噪声的治理措施及其展望。     

High-resolution electron microscopy of the twinning and intergrowth in Ca4Al6SO16 and Ca3SrAl6SO16

The microstructures of unhydrated calcium aluminosulphate Ca₄Al₆SO₁₆ and Ca₃SrAl₆SO₁₆ have been studied by high-resolution electron microscopy (HREM). The results showed that twinning and twinned slabs could be introduced taking the [1 1 2] direction as the twin axis so that it seems to be coincident with the law of twinning formed in body-centred cubic structures. A previously reported superlattice with a repeat period twice that of the fundamental structure along the 〈1 1 0〉 direction has also been found in both matrix and twin variants. The close intergrowth of Ca₃SrAl₆SO₁₆ and another phase, possibly Sr₃Al₂O₆ existing as an inclusion between these two twin variants, was determined and clearly revealed by electron diffraction and HREM images. The coherent interphase boundaries and orientation relationship between them can also be deduced.     

论坛消息的语义漂移分析

引入多维文档模型来组织论坛消息的描述性特征和语义性特征，并在多维索引的基础上，提出了加窗分析技术。目的在于分析论坛站点中语义漂移现象，进而发现论坛中的完整语义信息单元。     

Viable：设计折射生活体验

从上个世纪九十年代中期开始，无定型的造型在设计中占据了主导。十年之后，人们的审美和设计标准发生了变化。几何原理的广泛应用使得生活物品的设计出现了“硬边”（产品的棱线和轮廓）与“精确”之风的回潮。也许是人们渴望在这个不稳定的世界中寻求稳定的元素，也许是为了用简单直白的设计来掩饰以往设计中复杂计算的造型。总之，设计师对成熟稳重的几何形式表现得情有独钟。这种席卷而来的感觉体现了一种设计的成熟，而Viable工作室的设计就是其中的代表；不仅如此，他们的设计还反映出了每个人对生活的不同理解。[编者按]