基于双簇头非均匀分簇的LEACH协议的改进

在无线传感器网络中的LEACH协议是一种自适应聚类路由算法．由于LEACH协议存在着无法控制簇首在网络中的分布位置、簇首选择方式限制条件不够等缺点导致能量消耗太大．基于簇头能量限制和双簇头路由方式,对LEACH协议进行了改进,设计了一种降低能耗的双簇头非均匀分簇路由协议．双簇头非均匀分簇路由协议采用NS2进行网络仿真实验,通过仿真结果的分析以及与LEACH协议的对比,证明双簇头非均匀分簇路由协议有效提高了网络能耗的均衡性．     

UCRP—一种能量有效的WSN非均匀分簇路由协议

提出了一种新的能量有效的非均匀分簇路由协议—UCRP.根据距离基站的远近将网络分为大小不同的簇;簇内数据传输根据簇范围的大小采用单跳或多跳;簇间数据传输构建多跳路由,簇首选择下一跳节点时将能量与最小跳数路由算法相结合;最后在能量有效的前提下对LEACH协议易受到HELLO flooding攻击提出了安全设想.仿真结果表明:该协议能够有效地均衡簇首和全网能耗,延长网络生存时间.     

无线传感器网络能量均衡分簇路由协议

LEACH是无线传感器网络(Wireless Sensor Network,WSN)中一种经典的分层式路由协议,在此基础上通过对LEACH成簇算法及簇间路由的改进,提出了一种新的均衡能量消耗分簇路由协议。该协议在无线传感器网络成簇过程中充分考虑了传感器节点的能量状态,同时簇首向基站的通信采用基于能量的簇间路由。理论分析及仿真结果表明,改进的协议能够均衡传感器节点的能量消耗,有效地延长网络寿命。     

基于数据融合的无线传感器网络路由算法

在分簇协议LEACH和链状协议PEGASIS的基础上,提出一种新的基于数据融合的分簇路由算法.簇首节点采用多跳方式传输数据,并根据周围节点的密集程度构造不同大小的簇;簇内节点计算上行和下行节点构造数据融合树,采用时分复用调度算法进行多跳路由.NS2仿真结果表明该路由算法均衡了各个节点的能量消耗,延长了网络存活时间,并降低了网络延迟.     

基于最小生成树的LEACH协议改进

LEACH(Low Energy Adaptive Clustering Hierarchy)是一种被广泛应用于无线传感网络的路由协议.本文针对LEACH协议中,远距离节点作为簇首时能量消耗过多的缺点,提出了一种改进的无线传感网络路由协议.多跳传输LEACH改进协议在节点选出簇首之后,采用最小生成树中Prim算法,在簇首与基站间采用多跳传输.为克服多跳传输时距基站第一跳的簇首能量消耗较多的缺点,阈值需要采用节点距基站的距离和节点距簇首的平均距离来调整,已达到平衡节点能量消耗的目的.仿真结果表明,改进的算法可减少和均衡能量消耗,提高能量的使用,以及延长整个网络寿命方面具有很大的优势.     

基于环形搜索的WSN簇间最优路由选择

为了解决LEACH协议中由单跳路由算法造成的节点能量消耗不均衡的问题,首先,计算分析得出簇间多跳的最优跳数,得到簇头节点到基站的一条理想路径;然后,提出一种环形搜索方法去寻找与理想路径最接近的最优路径;最后,提出了簇头到基站的多跳路由算法。仿真实验结果表明,簇头到基站的多跳路由算法较LEACH协议在均衡节点能量消耗和延长网络生命时间方面的性能有明显的提高。     

无线传感器网络功率路由算法研究

无线传感器网络的应用越来越广泛,主要是军事、工业、医疗等方面。然而无线传感器网络具有节点能量、存储和计算能力非常有限等特点,文中在传统的LEACH（低功耗自适应集簇分层型）协议的基础上进行了改进,并提出了一种新的无线传感器网络路由算法LEACH-N。新算法沿用了LEACH协议簇的结构,在簇头选择方法上基于传统DCHS算法的簇头选择算法,簇内成员与簇头之间直接通信,簇头与基站之间轮流进行单跳和多跳通信;多跳通信则是采用一种改进的MTE（最小传输能量）路由算法。通过NS2仿真软件对LEACH-N协议与LEACH协议分别进行了性能测试。实验结果表明,相比LEACH协议,LEACH—N协议系统能耗低、网络生命周期长,且具有更好的规模可扩展性。     

基于二跳信息的分簇算法

对于低功耗自组织的无线传感器网络,其路由协议和拓扑控制受到了很多学者的关注,且已成为国际的研究热点.在分析了LEACH,FSR算法的基础上,提出了一种基于二跳信息的分簇算法,以有效提高网络生命期.着重对算法的设计思想和工作过程,包括簇首选择与簇建立,簇成员通信等进行了分析和论述.仿真结果表明本文中的算法对于LEALCH能有效提高网络生命期.     

WSN中一种基于LEACH的协同通信算法的研究

近年来,协同通信在无线传感器网络中取得了很大的应用,重点分析和研究了一种基于低功耗自适应集簇分层型协议（LEACH）的协同通信算法;在该算法中,通过选择合适的协同节点来发送数据可以有效的减少簇头节点的能量消耗,并且与多跳传输相比,又节省了路由更新耗费的能量,实验仿真证明基于LEACH的协同算法（LEACH-COOP）在能量消耗上与LEACH和基于LEACH的簇头多跳算法（LEACH-MH）相比表现出了更优的性能。     

一种基于LEACH路由协议的改进算法

无线传感器网络的生存时间受传感器节点软硬件条件的限制,改进传感器网络路由协议是延长网络生存时间的有效途径。LEACH协议是最早提出的经典分层路由协议,文中基于LEACH协议提出改进,应用K-medoids算法改进LEACH协议的簇首分簇机制,并通过Matlab仿真实验,证实了改进后的LEACH算法在均衡化网络能耗,延长网络的生命周期方面具有优越性。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.