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991.
利用传感技术为监测手段开发一套基于3G传输网络的道路气象预警系统,使道路管理部门精确掌握气象资料和天气预报,并根据各路段的地形及气候特点,结合路段交通状况,制定各自的应急预案,以保证道路的行车安全和顺畅。此系统对道路沿线气象状况进行监测、分析并采取有效的应急预案,对保障道路过往车辆和人身财产安全有着积极作用。 相似文献
992.
针对数字图书馆应用服务中的数据查询问题,提出了一种基于云计算的数据查询方法.首先,基于Random Walk方法找到查询请求的目标节点,然后,通过定义服务节点的相似节点集和等价节点集来进行二次搜索,返回具有最大评价值和最低负载的节点和数据作为所需的目标节点及数据.实验结果表明,在查询的数据质量、服务节点的负载能力以及查询的效率方法都优于传统的方法. 相似文献
993.
Effects of Copper Coating on the Crystalline Structure of Fine Barium Titanate Particles 总被引:1,自引:0,他引:1
Xinghua Liu Wan Y. Shih Wei-Heng Shih 《Journal of the American Ceramic Society》1997,80(11):2781-2788
We have investigated the effect of a metal coating—copper—on the tetragonal structure of fine barium titanate (BaTiO3 ) particles. The BaTiO3 particles were synthesized by a sol-gel method and heat treated at temperatures >900°C for various amounts of time before coating. The copper coating was achieved by an electroless coating technique. The transmission electron microscopy micrographs revealed that the coated powder contained fine BaTiO3 particles that were embedded in copper patches. The X-ray diffractometry patterns showed that the copper coating increased the c/a ratio of the fine BaTiO3 particles. For powders that were heat treated at 900°C for 10 h and were initially cubic, the copper coating changed the c/a ratio, from 1 to 1.0034. For powders that were calcined at 900°C for 20 h and were initially tetragonal, the copper coating further enhanced the c/a ratio, from 1.0028 to 1.0043. When the copper-coated BaTiO3 particles were oxidized, the c/a ratio was reduced to a value that was approximately equal to or below that of the uncoated powders. A conductive coating can eliminate the depolarization energy of an insulating polar particle. The fact that the copper coating promoted the polar tetragonal phase but the nonconductive copper-oxide coating did not was consistent with the interpretation that the presence of the cubic phase (nonpolar) in small BaTiO3 particles was caused by the depolarization effect. 相似文献
994.
An EGF-pseudomonas exotoxin A recombinant protein with a deletion in toxin binding domain specifically kills EGF receptor bearing cells 总被引:2,自引:0,他引:2
Lee Chi-Hon; Lee E-Ching; Tsai Shih-Tzer; Kung Hsing-Jien; Liu Yin-Chang; Hwang Jaulang 《Protein engineering, design & selection : PEDS》1993,6(4):433-440
We constructed two chimeric toxins; one composed of epidermalgrowth factor (EGF) and pseudomonas exotoxin A (PE), designatedEGF-PE and the other composed of EGF and PE with a deletionof the Ia domain (cell-binding domain), designated EGF-PE (Ia).Both chimeric toxins reacted with anti-EGF and anti-PE antibodies.The cell-killing experiments showed that EGF-PE, but not EGF-PE(Ia),was cytotoxic to the murine fibroblast cell line NR6, whichcarried the PE receptor, but not the EGF receptor. However,after NR6 was transfected with DNA for the expression of humanEGF receptor, the transfected cell line, designated NRHER5,overexpressed human EGF receptors and became sensitive to EGF-PE(IA).The cytotoxicity of EGF-PE(Ia), but not EGF-PE, to NRHER5 canbe completely blocked by an excess amount of EGF. To completelyreverse the cytotoxicity of EGF-PE on NRHER5, both the EGF receptorpathway and the PE receptor pathway need to be blocked. Theseresults suggest that EGF-PE exhibits both EGF and PE bindingactivities, while EGF-PE(IA) possesses only EGF binding activity.Thus, EGF-PE(Ia) may be a better chimeric toxin than EGF-PEin terms of target specificity to EGF receptor bearing cells.We, therefore, examined the cytotoxicity of EGF-PE(Ia) to varioushuman cancer cell lines. We find that human cancer cells containingmore EGF receptors are more sensitive to EGF-PE(Ia). 相似文献
995.
996.
本文报道Ni(naph)_2-n-C_4H_9Li-BF_3·OEt_2催化体系对丁二烯的聚合活性.发现.只有Ni(naph)_2与n-C_4H_9Li二元陈化方式有较好的聚合活性.聚合物的特性粘度[η]和5%苯乙烯的动力粘度(η_(c.p)均低.顺式-1,4结构含量约为94%.几乎不生成凝胶。 相似文献
997.
LIU Lin YANG Chen WANG JianMin YE XiaoJun LIU YingBo YANG HongJi LIU XiaoDong 《中国科学:信息科学(英文版)》2014,57(6):1-19
Today’s software systems need to support complex business operations and processes.The development of the web-based software systems has been pushing up the limits of traditional software engineering methodologies and technologies as they are required to be used and updated almost real-time,so that users can interact and share the same applications over the internet as needed.These applications have to adapt quickly to the diversified and dynamic changing requirements in the physical,technological,economical and social environments.As a consequence,we are expecting a major paradigm shift in software engineering to reflect such changes in computing environment in order to better address the fundamental needs of organisations in this new era.Existing software technologies,such as model driven development,business process engineering,online(re-)configuration,composition and adaptation of managerial functionalities are being repurposed to reduce the time taken for software development by reusing software codes.The ability to dynamically combine contents from numerous web sites and local resources,and the ability to instantly publish services worldwide have opened up entirely new possibilities for software development.In retrospect to the ten years applied research on Internetware,we have witnessed such a paradigm shift,which brings about many changes to the developmental experience of conventional web applications.Several related technologies,such as cloud computing,service computing,cyber-physical systems and social computing,have converged to address this emerging issue with emphasis on different aspects.In this paper,we first outline the requirements that the Internetware software paradigm should meet to excel at web application adaptation;we then propose a requirement model driven method for adaptive and evolutionary applications;and we report our experiences and case studies of applying it to an enterprise information system.Our goal is to provide high-level guidelines to researchers and practitioners to meet the challenges of building adaptive industrial-strength applications with the spectrum of processes,techniques and facilities provided within the Internetware paradigm. 相似文献
998.
Ke Xu Min Zhu GuangWu Hu Liang Zhu YiFeng Zhong Ying Liu JianPing Wu Ning Wang 《中国科学:信息科学(英文版)》2014,57(11):1-24
There is a general consensus about the success of Internet architecture in academia and industry. However, with the development of diversified application, the existing Internet architecture is facing more and more challenges in scalability, security, mobility and performance. A novel evolvable Internet architecture framework is proposed in this paper to meet the continuous changing application requirements. The basic idea of evolvability is relaxing the constraints that limit the development of the architecture while adhering to the core design principles of the Internet. Three important design constraints used to ensure the construction of the evolvable architecture, including the evolvability constraint, the economic adaptability constraint and the manageability constraint, are comprehensively described. We consider that the evolvable architecture can be developed from the network layer under these design constraints. What's more, we believe that the address system is the foundation of the Internet. Therefore, we propose a general address platform which provides a more open and efficient network environment for the research and development of the evolvable architecture. 相似文献
999.
数字技术的迅速发展和广泛应用,互联网、电信移动网络等新兴传输方式和手机、机顶盒、电脑等多媒体终端极大地拓展了数字内容的传输范围。数字内容版权保护的问题日益突出,本文从立法和技术角度阐释了数字内容的版权保护,并提出了数字内容版权保护的建议。 相似文献
1000.