城市垃圾收运系统优化模型研究综述

在综述国内外城市生活垃圾收运现状的基础上，从收运设施规划、收运调度以及收运路线优化等三方面详细分析了当前国内外收运系统优化模型的研究进展，总结了研究成果，指出了研究缺乏系统性和实际应用性，并提出了建立中转站规划-调度一体化优化模型和在规划基础上的优化路线的优化模型的整体研究框架，为我国大城市和人口密集背景下的生活垃圾收运系统的研究及完善提出了前进方向。     

控制CO2排放的能源科技战略综合研究

探索符合我国国情的控制CO2排放的技术路线和政策，是本世纪能源、环境和管理三个学科领域共同关心的重要研究议题。在能源环境交叉领域寻求潜力和突破口，同时强调技术路线研究与政策决策研究之间的有机结合。通过分析控制CO2的科技难点，探索能量转化利用与CO2分离一体化原理、能源环境相容的系统集成理论，提出了低能耗甚至零能耗分离CO2的新型能源环境系统，给出了适用于控制CO2排放的技术路线和政策综合评价的方法学和模型体系框架。还构思了适合我国国情的控制CO2排放的全国能源网络和政策框架，试图开辟能源与温室气体控制协调发展的新方向。     

基于S3C2416的公交电子站牌系统设计

为了提高城市公交的运营效率和服务质量,让乘客及时了解公交车实时车况,设计了一种基于S3C2416微处理器的新型公交电子站牌系统,并对该系统的组成、工作原理、关键技术及主要模块的软硬件设计进行了详细的阐述.系统以ARM为嵌入式硬件平台,采用当前先进的嵌入式技术和GPRS无线网络通信技术,实现了车辆到站预报、车辆到站提示、公交站点查询、公交车次查询等功能.测试结果表明,该系统性能良好、实时性强、稳定性高,具有巨大的市场价值.     

带转向约束的城市垃圾收集车辆弧路径问题研究

考虑部分街道单行及转向限制等状况，采用带有转向禁忌条件的垃圾收集车辆弧路径问题模型对城市垃圾收运路线进行优化。建立将其转换为对应的点路径问题的求解模型，以减少问题规模；并使用聚类蚁群算法对该问题进行求解。成都市双楠辖区的实例优化结果表明，有/无转向约束的路线优化后，总路程分别减少了89984．96m和92330．04m，节约了31．1％和31．9％。效果明显。此外，优化后减少了需求车辆数，减少了车辆使用成本和人员雇佣成本。     

高速公路目标持续性评价研究

本文介绍了我国高速公路目标持续性评价的现状和目前存在的问题，提出高速公路可持续发展目标和目标可持续评价的内容体系。总结了高速公路目标持续性评价的特点，对目标持续性评价的原则方法、技术路线和方法进行了探讨与分析。     

2-氯丙酸的生产技术概况

2-氯丙酸是合成农药、染料和农林化学品的重要原料。本文缘述了国内外2-氯丙酸的合成方法及各种方法的工艺条件，分析了各种方法的优缺点，并展望了2-氯丙酸合成路线的发展趋势。     

3S技术在江汉平原湿地监测中的应用

文章以江汉平原湿地监测为例，就3S技术在湿地监测中的应用做了说明。文章在简述江汉平原自然地理概况、江汉平原湿地3S技术监测意义的基础上，分析了进行湿地3S监测的技术方法与流程路线，建立了相应的湿地类型解译标志，并就湿地监测过程中的一些技术问题进行了讨论。     

东台吉乃尔盐湖夏季卤水25℃等温蒸发实验研究

针对东台吉乃尔盐湖夏季卤水进行25℃等温蒸发实验研究，揭示卤水蒸发结晶路线和析盐规律。实验结果表明：夏季盐湖卤水蒸发析盐过程依次为石盐、石膏、软钾镁矾、泻利盐、钾石盐、六水泻盐、钾盐镁矾、光卤石、一水硫酸锂和水氯镁石，并将分阶段析盐序列绘制在相应的介稳相图上，结晶路线与介稳相图基本吻合。     

二氧化碳捕集技术研究现状与发展综述

为应对全球气候变暖，减少CO₂向大气排放，CO₂捕集成为全球重点研究的一项技术。本文基于国内外CO₂捕集技术研究现状，将CO₂捕集技术分为燃烧前捕集、燃烧后捕集、富氧燃烧和化学链燃烧4种技术路线，燃烧前捕集和燃烧后捕集技术又主要有吸收法、吸附法、膜分离法、低温分馏法等方法。首先，概述了这4种技术路线的不同方法的研究现状和应用进展，并提出了各技术方法的未来发展趋势。随后，对比了不同CO₂捕集技术的优缺点，总结发现各技术方法各有利弊，尚未有一种技术能独立满足高效、低成本、低能耗和大规模要求。最后，提出未来应当针对CO₂捕集技术存在的难题与挑战，重点开展研发攻关，突破现阶段瓶颈，推动CO₂捕集经济、高效和规模化。     

西调渤海水改造北方沙漠与遏制北京沙尘暴

从我国北京向西，一次分布着七大沙漠，它们是：浑善达克沙地，毛乌素沙漠，库不齐沙漠、乌蓝布和沙漠、腾格里沙漠，巴丹吉林沙漠，塔克拉玛干沙漠，空间上它们是呈纬向连续展布的，渤海深深迁入我国北方大陆500多公里，距离北方沙漠极近，本文提出以渤海为改造沙漠的水源；探讨了沙尘暴进入北京的路径与治理对策；论证了东方（渤海）西调路线与大致工程阶段；并对调水线路各段之地理环境特点与施工条件进行了科学分析。     

Use of the degeneracy of the genetic code by selective pressure to cut up genes of procaryote genomes

The DNA sequences of three bacteriophages are analysed in order to localise those parts coding for a protein. A weak stability on the DNA molecule allows us to characterize the beginning and the end of genes. A survey of the codons used shows that the cause for this weak stability is the systematic use of A-T bases in third position, which is made possible by the degeneracy of the genetic code.     

Short sequence repeats in microbial pathogenesis and evolution

Repetitive DNA is ubiquitous in microbial genomes. Different classes of short sequence repeats (SSRs) have been identified and demonstrated to be generally heterogeneous in a locus-dependent manner, reflected in variation in the number of repeat units present at a given genomic site or by sequence heterogeneity among individual units. Both types of variability can be used to assess intra-species genetic diversity. Repeat variability often affects the coding potential of the region in which the repetitive element is located. This implies that determination of the primary structure of variable numbers of tandem repeats can be used for epidemiological identification purposes, and also for the analysis of gene function. Precise assessment of SSR structure can also generate insight into the regulation of gene expression. Together, DNA repeat analysis in microbial species provides information on both functional and evolutionary aspects of genetic diversity among microbial isolates.     

The bacterial translocase: a dynamic protein channel complex

The major route of protein translocation in bacteria is the so-called general secretion pathway (Sec-pathway). This route has been extensively studied in Escherichia coli and other bacteria. The movement of preproteins across the cytoplasmic membrane is mediated by a multimeric membrane protein complex called translocase. The core of the translocase consists of a proteinaceous channel formed by an oligomeric assembly of the heterotrimeric membrane protein complex SecYEG and the peripheral adenosine triphosphatase (ATPase) SecA as molecular motor. Many secretory proteins utilize the molecular chaperone SecB for targeting and stabilization of the unfolded state prior to translocation, while most nascent inner membrane proteins are targeted to the translocase by the signal recognition particle and its membrane receptor. Translocation is driven by ATP hydrolysis and the proton motive force. In the last decade, genetic and biochemical studies have provided detailed insights into the mechanism of preprotein translocation. Recent crystallographic studies on SecA, SecB and the SecYEG complex now provide knowledge about the structural features of the translocation process. Here, we will discuss the mechanistic and structural basis of the translocation of proteins across and the integration of membrane proteins into the cytoplasmic membrane.Received 10 January 2003; received after revision 2 April 2003; accepted 4 April 2003     

基于多级编码的分布式信源编码

分布式信源编码是无线通信领域研究的新热点，本文阐述了分布式编码的基础理论，介绍了应用于分布式编码的LDPC编码方法和多级编码方案，最后提出一种基于多级编码的分布式编码方案，实验结果表明该方案在一定的信噪比下获得了较高的编码效率，灵活地控制了传输码率。     

软件无线电技术及其在WiMAX中的应用

软件无线电是通信领域继模拟到数字、固定到移动通信的第三次革命。本文介绍了软件无线电提出的背景，软件无线电技术在移动终端和基站中的应用以及适用于WiMAX802．16技术的软件无线电基站结构。     

山区道路选线及其相关的环境问题

在西部大开发中，山区道路选线问题突出，本文从地形选线、地质选线和环境选线的角度总结了山区道路选线的研究现状，在分析了山区道路选线中存在的问题的基础上，提出了今后的发展趋势及应该进一步深入研究的问题。为山区道路选线理论与方法的进一步研究提供服务。     

天宫一号与载人飞船组合体能源管理设计与验证

天宫一号和载人飞船构成组合体期间,载人飞船处于停靠状态,由天宫一号负责组合体能源管理.基于供电安全性和传输功率的要求,组合体进行了近端采样反馈电压控制的并网供电架构设计.经过仿真、地面测试和在轨飞行试验验证,表明天宫一号与载人飞船组合体供电并网设计正确,为载人空间站工程各组合体间供电并网设计提供了有力保证.     

Genetic code 1990. Outlook

The genetic code is evolving as shown by 9 departures from the universal code: 6 of them are in mitochondria and 3 are in nuclear codes. We propose that these changes are preceded by disappearance of a codon from coding sequences in mRNA of an organism or organelle. The function of the codon that disappears is taken by other, synonymous codons, so that there is no change in amino acid sequences of proteins. The deleted codon then reappears with a new function. Wobble pairing between anticodons and codons has evolved, starting with a single UNN anticodon pairing with 4 codons. Directional mutation pressure affects codon usage and may produce codon reassignments, especially of stop codons. Selenocysteine is coded by UGA, which is also a stop codon, and this anomaly is discussed. The outlook for discovery of more changes in the code is favorable, and open reading frames should be compared with actual sequential analyses of protein molecules in this search.     

Chromosomal organization at the level of gene complexes

Metazoan genomes primarily consist of non-coding DNA in comparison to coding regions. Non-coding fraction of the genome contains cis-regulatory elements, which ensure that the genetic code is read properly at the right time and space during development. Regulatory elements and their target genes define functional landscapes within the genome, and some developmentally important genes evolve by keeping the genes involved in specification of common organs/tissues in clusters and are termed gene complex. The clustering of genes involved in a common function may help in robust spatio-temporal gene expression. Gene complexes are often found to be evolutionarily conserved, and the classic example is the hox complex. The evolutionary constraints seen among gene complexes provide an ideal model system to understand cis and trans-regulation of gene function. This review will discuss the various characteristics of gene regulatory modules found within gene complexes and how they can be characterized.