动态WSN下生命周期最优化方法

探索复杂环境下动态无线传感器网络中生命周期优化模型与优化方法,对由此引出的理论问题及关键技术开展深入研究.首先突破传统静态网络模型在刻画事件能力的局限性,通过时间轴扩展的方式,将静态模型扩展成动态网络模型.在此基础上,引入网络流理论,对动态无线传感器网络中生命周期优化问题进行数学建模.最后,引入Linear Programming计算方法,对优化方程进行求解,突破此问题在计算复杂度方面的制约,创建了一种新型的路由调度优化算法.     

From defects creation to circuit reliability - A bottom-up approach (invited)

This paper presents a theoretical framework about interface states creation rate from Si-H bonds at the Si/SiO₂ interface. It includes three mains ways of bond breaking. In the first case, the bond can be broken thanks to the bond ground state rising with an electrical field. In the two others cases, incident carriers will play the main role either if there are very energetic or very numerous but less energetic. This concept allows us physically modeling the reliability of MOSFET transistors, and particularly NBTI permanent part, and Channel Hot Carrier (CHC) to Cold Carrier (CCC) damage. Finally, the translation of these physical models into reliability spice models is discussed. These models pave the way to Design-in Reliability (DiR) approach which seeks to provide a quantitative assessment of reliability - CMOS device reliability in this case - at design stage thereby enabling judicious margins to be taken beforehand.     

LED的寿命,你真正理解了吗?

LED技术起始于半导体行业,却带给照明行业应用上的大发展。作为一个新兴事物,有很多问题都在探索当中。LED一个显著的特点就是超长寿命。但没有确切的试验,这超长寿命是如何得来的?它与传统照明理解的寿命有什么不同吗?本文将从LED寿命这个看似简单的问题作为出发点,来系统的分析和梳理LED元件及系统的寿命问题。通过比较与传统照明的异同点,分析当今最新标准来帮助LED的使用者和系统制造商理解和推导真正的LED的寿命。     

基于联合节点行为策略的WSN覆盖控制算法

针对无线传感器网络在对移动目标节点覆盖过程中出现网络能量快速消耗问题，提出了一种基于联合节点行为策略的覆盖算法。根据网络模型建立传感器节点与目标节点从属关系，确定覆盖关联模型；利用概率理论求解邻居节点冗余覆盖度，确定最少传感器节点数量；给出了邻居节点覆盖期望值的求解方法；仿真实验表明，该算法与其他算法在网络覆盖率和网络生存周期两个性能指标上均提升了12.39%和15.01%，从而验证了算法的有效性。     

一种基于Ad Hoc网络的协作MAC方案

在 IEEE 802.11b MAC层协议的研究基础上,提出了一种基于无线Ad Hoc网络的最佳中继选择策略,该策略综合考虑瞬时信道信息和节点剩余能量,能够有效防止信道条件好的节点的过度使用,并能保证系统高吞吐量。文中以饱和吞吐量和网络生存时间为性能指标,对新算法和以往协作MAC算法进行仿真和比较,结果表明新算法在网络吞吐量下降不明显的情况下,能大大增加网络生存时间。     

电子装备加速实验中的故障预测方法

现代电子装备结构复杂,故障规律难以掌握。而通过对装备组成单元故障规律的研究可推导出装备整体故障规律并进行故障预测。本文着手于对装备组成单元故障规律和故障预测方法的研究。首先利用加速试验来缩短装备组成单元试验时间,获取大量故障规律信息;对加速试验的数据进行了处理;然后基于灰色预测理论,将加速试验中获得的故障规律外推,推测出装备组成单元在正常应力水平下的故障规律并进行故障预测;最后利用相似度和“年老”隶属函数给出了预测结果的可信度。     

碳剥离膜寿命的研究

碳剥离膜用交流电弧法或者直流电弧法来制备,也可用交直流电弧来做多层膜.对不同制备方法和结构的碳剥离膜寿命进行了测量,所测膜的厚度为19μg/cm2.对影响膜寿命的一些因素进行了讨论,尤其是制备方法和碳膜结构.测量结果表明用直流电弧所做的碳膜寿命比交流电弧所做的长.     

Field effect surface passivation of SiO2/Si interfaces by heat treatment with high-pressure H2O vapor

We investigated a simple field effect passivation of the silicon surfaces using the high-pressure H₂O vapor heating. Heat treatment with 2.1×10⁶ Pa H₂O vapor at 260°C for 3 h reduced the surface recombination velocity from 405 cm/s (before the heat treatment) to 38 cm/s for the thermally evaporated SiO_x film/Si. Additional deposition of 140 nm-SiO_x films (x<2) with a high density of fixed positive charges on the SiO₂/Si samples further decreased the surface recombination velocity to 22 cm/s. We also demonstrated the field effect passivation for n-type silicon wafer coated with thermally grown SiO₂. Additional deposition of 210 nm SiO_x films on both the front and rear surfaces increased the effective lifetime from 1.4 to 4.6 ms. Combination of thermal evaporation of SiO_x film and the heat treatment with high-pressure H₂O vapor is effective for low-temperature passivation of the silicon surface.