Survey on Connectivity with Mobile Elements in WSNs

节点连通性是无线传感器网络研究的热点问题之一,然而由于节点能量耗尽、硬件故障以及通信链路失效等问题的存在,造成网络分割,因此如何确保网络连通成为; 无线传感器网络亟待解决的关键性问题.近年来,一个新的研究趋势是通过引入计算能力较强且能量较为充足的移动性节点来进行连通控制,提高无线传感器网络的; 整体性能.本文对目前利用移动性节点的主流连通控制方法进行了充分调研,通过对这些方法的详细分类和比较,归纳了移动式连通控制的各类方法的特点,分析了; 这些方法的性能和适用范围,总结了研究中存在的主要问题与挑战,并指出了未来可能的研究方向.The connectivity of sensors is one of the main research problems in; wireless sensor networks (WSNs).Data can be forwarded through connected; sensor nodes.However,becauseof energy depletion,hardware failure and; communication link failure,the network may be partitioned.How to; guarantee the connectivity becomes an urgent issue in wireless sensor; networks.Traditional work usually focuses on maximizing the connectivity; with minimum sensors.In recent years,a new research trend is to utilize; mobile elements for connectivity control.Since the mobile element is; more powerful than normal sensors,it improves the performance of many; aspectsin wireless sensor networks.In this paper,we makea comprehensive; investigation about the current major connectivity control methods with; mobile elements.We first summarize the characteristics of mobile; topology control methods via a new classification.Based on the; classification,these methods are compared to each other according to a; serial parameters.Finally,we analyze the performances and the; application scopes of these methods,summarize the main problems,and; point out the future research directions.国家"九七三"重点基础研究发展计划项目; 国家科技支撑计划项目; 国家自然科学基金项目; 福建省科技计划重点项目; 福建省自然科学基金计划项

Survey on Coverage Control with Mobile Elements in Wireless Sensor Networks

在无线传感器网络中,节点能量限制、硬件以及通信链路故障等问题,造成网络空洞的产生且影响了网络的正常运作,因此如何确保网络覆盖率成为传感器网络中需; 要解决的重要问题.近年来,通过引入移动节点来进行覆盖控制,提高传感器网络的覆盖率成为一个新的研究趋势.本文通过充分调研利用移动节点进行网络覆盖控; 制的方法,并对其进行了分类和比较,归纳了移动式网络覆盖的各种方法的特点,分析这些方法的性能和适用范围,总结存在的主要问题,并指出未来的研究方向.Due to the existence problems of energy depletion,hardware failure and; communication link failure and so on,which causes network holes and; affects the normal network operation. The insurance of coverage becomes; an urgent issue in wireless sensor networks. In recent years, a new; research trend is to utilize mobile nodes for coverage control, which; increases the coverage of wireless sensor networks. In this paper, we; have a comprehensive investigation about the current major topology; control methods with mobile nodes,and summarize the characteristics of; mobile topology control methods via classification and comparison of; these methods. Finally,we analyze the performances and the application; scopes of these methods, summarize the main problems,and point out the; future research directions.国家自然科学基金重点项目; 国家科技支撑计划项目; 国家自然科学基金项目; 福建省科技计划重点项

术前口服倍他乐克对于麻醉诱导丙泊酚的用量和血流动力学的影响

【目的】本研究探讨术前口服倍他乐克对麻醉诱导时丙泊酚的用量和血流动力学变化的影响。【方法】选择择期手术的全麻病人（ASAⅠ～Ⅱ）60例，随机分成两组，每组30例，第一组为实验组（B组），术前口服倍他乐克50mg，第二组为对照组（C组）给予安慰剂；以30mg·kg^-1·h^-1的恒速灌注丙泊酚至BIS达到50，记录病人入睡时和BIS=50时丙泊酚的用量以及插管前后血压、心率、中心静脉压和心输出量变化。【结果】两组病人入睡时丙泊酚的用量：B组是（1_35±0．22）mg·kg^-1；C组是（1．60±0．24）mg·kg^-1，组间差异P〈0．01；BIS=50时的丙泊酚的用量：B组是（1．71±0．27）mg·kg^-1；C组是（1．98±0．24）mg·kg^-1；组间差异P〈0．01；B组插管前、后血压和心率的变化程度较C组小（P〈0．05），插管过程中心静脉压和心输出量组间变化差异不大。【结论】术前口服倍他乐克50mg减少麻醉诱导丙泊酚的用量，插管时的血流动力学相对稳定

Electrochemical micromachining microstructure lattice on magnesium alloy surface

Micromachining of magnesium alloy by confined etchant layer technique (CELT) was investigated. The variation of hydrogen ion concentration on the electrode surface during the electrochemical process was explored for some thermodynamically available "etchant-scavenger" systems, and their corrosion rate to magnesium alloy was measured. An effective electrochemistry "etching-scavenging" system was selected. Using NaNO2 as precursor for electrochemically generating etchant HNO3, NaOH as scavenger, and small amount of Na2SiO3 as inhibitor, 3-D microstructure lattice on a mold was replicated onto the magnesium alloy surface. The microstructures processed were approximately the negative copy of the ones on the mold. Sub-micrometer scale resolution was reached. The result suggested that CELT could be applied to machine the 3-D microstructure on magnesium alloy surface, which had potential to be used for the fabrication of micro electromechanical systems (MEMS)

水文资料整编系统HDP（网络版）在基层工作中的推广与应用

水文资料整编系统HDP(网络版)突破了传统的整编工作流程,水文数据库具有唯一性、实时性。测验、整编人员在水文测验完成后及时录入整编系统网络数据库,技术管理人员实时完成审查工作,反馈审查意见,将整编与审查交叉进行。实时为昀严格水资源管理、防汛测报提供技术支撑。结合工作实际本文从该系统的组织结构、在线实时整编流程、整编工作管理及该系统的功能与扩展等多方面介绍该系统在基层工作中的推广与应用。</jats:p