数字地图制图中居民地和道路关系处理

为了解决数图转换过程中要素之间的关系,基于国家基础地理信息,根据现有居民地分类情况,总结了数字制图环境下居民地与道路之间的关系,主要包括依比例尺、半依比例尺及不依比例尺居民地和道路之间的关系;结合国家1:250000和1:50000基础地理信息及不同比例尺数据采集成果,详细给出了不同情况下居民地和道路之间关系的处理方法,主要包括调整图层显示顺序、删除重复采集数据及移位等;基于Vc++和Oracle数据库,就国家1:250000和1:50000中居民地和道路之间关系的自动处理进行了实验。实验表明,利用此方法,对同类问题的解决具有一定的参考价值。     

论公路施工进度计划安排及工期的保证体系和措施

在公路建设中,施工进度计划的合理与否往往是制约工期的关键。文章提出了施工进度计划的安排原则,即从工期的保证体系、组织管理措施、技术保证措施、经济保证措施、资源保证措施、合同保证措施等几个方面进行了论述。     

高校图书馆导读服务的实践与思考

提供优质服务是图书馆的核心价值,而导读则是其中一种主要的服务形式。介绍了导读服务的作用、意义和原则,论述了开展导读服务工作的举措,以期提高高校图书馆的服务质量。     

Microstructure of Ba0.615Sr0.35Mg0.035TiO3 dielectric ceramics via X-ray spectrum analysis

The compound Ba0.615Sr0.35Mg0.035TiO3 was analyzed by the X-ray dispersed spectroscopy analyzer (SEM-EDAX) with the spec-trum image method, a powerful tool for chemical phase identification. The method was first time applied on a ceramic material to collect spectrum image and was progressed to identify the Mg-enriched component with fine scale pocket shown in matrix. This result, together with the stoichiometry result obtained from spot mode spectrum analysis, strongly confirmed the microstructure and properties of dielectric materials.     

让历史重返自然——当代STS的本体论研究

从逻辑经验主义到社会建构的发展中,自然的历史性始终未能进入研究者的视野。认识论的鸡之争使拉图尔提出了广义对称性原则,这一原则使自然的历史性以一种全新的面貌再现,使STS走向了新自然辩证法的本体论研究,这种本体论表明客体之所以能成为科学的,是因为它是在辩证的实践过程中生成的;客观性与真理等一系列认识论范畴也不是对预先存在对象的表象性反映,也是在历史与时间进程中生成的东西;科学是一个人与物、自然与社会共同进化的过程。     

Receding horizon H∞ control for discrete-time Markovian jump linear systems

Receding horizon H∞ control scheme which can deal with both the H∞ disturbance attenuation and mean square stability is proposed for a class of discrete-time Markovian jump linear systems when minimizing a given quadratic performance criteria. First, a control law is established for jump systems based on pontryagin’s minimum principle and it can be constructed through numerical solution of iterative equations. The aim of this control strategy is to obtain an optimal control which can minimize the cost function under the worst disturbance at every sampling time. Due to the difficulty of the assurance of stability, then the above mentioned approach is improved by determining terminal weighting matrix which satisfies cost monotonicity condition. The control move which is calculated by using this type of terminal weighting matrix as boundary condition naturally guarantees the mean square stability of the closed-loop system. A sufficient condition for the existence of the terminal weighting matrix is presented in linear matrix inequality (LMI) form which can be solved efficiently by available software toolbox. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the proposed method.     

二级学院图书馆发展的机遇与挑战——以海南大学二级学院图书馆为例

介绍了海南大学二级学院图书馆的现状,并针对合并后的新海南大学15个二级学院图书馆在新的历史发展中遇到的问题,提出了一系列解决的办法。     

聚乙二醇支持的CuI催化Huisgen环加成反应合成三氮唑(英文)

我们发展了聚乙二醇(PEG4000)支持的CuI催化的Huisgen环加成反应合成三氮唑衍生物的新颖方法.在聚乙二醇(PEG4000)支持的CuI的催化下,芳基叠氮和末端炔的Huisgen环加成反应以较高的收率得到三氮唑衍生物.初步研究负载催化剂的回收使用情况.     

Ancient DNA sequences of rice from the low Yangtze reveal significant genotypic divergence

Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, such as the spikelet bases of ancient grains, has been used to speculate on the domestication process and domestication rate of rice. In this study, we sequenced 4 genomic segments from rice remains in Tianluoshan, a site of the local Hemudu Neolithic culture in the low Yangtze and two other archaeological sites (~2400 and 1200 BC, respectively). We compared our sequences with those of the current domesticated and wild rice (O. rufipogon) populations. At least two genotypes were found in the remains from each site, suggesting a heterozygotic state of the rice seeds. One ancient genotype was not found in the current domesticated population and might have been lost. The rice remains belonged to the japonica group, and most if not all were japonica-type, suggesting that the remains might be at an early stage of indica-japonica divergence or an indica-japonica mixture. We also identified sequences with significant similarity to those from species of Sapindales, Zygophyllales, and Brassicales, which is consistent with the identification of other plant remains in the Tianluoshan site and the common rice field weeds such as mustards in southern China.     

化矿实验室设计与施工

随着出入境商品的多元化、复杂化,很多地方的质检部门在不断加大设备投入的同时也对实验室进行了改造或重建。特别是实验室的重新规划设计和建设,是一项十分复杂的系统工程,做好这项工作需要创新,更需要经验积累。结合实验室基建工作实践,总结了经验、提出了看法。