干涉检测数据抗振动影响的方法研究

在光学元件的抛光阶段,通常采用干涉仪检测光学元件的面形数据,对加工工作提供指导意见。移相干涉术易受环境振动的干扰,获得的波前相位的干涉图信息不完整,难以准确给出光学元件表面的干涉数据。为了利用干涉仪检测数据给出被测光学元件面形上的各点准确数据,采用等精度测量消除随机误差的方法,对多次检测数据求取平均值以获取被测光学元件面形的准确数据。针对一块Φ1200mm口径的圆形光学元件的实验表明这种方法可以较为有效地消除检测中振动因素的影响。     

基于模数的干涉相位自适应中值滤波法

为了改善对干涉相位噪声的抑制效果而又确保有用相位跳变信息不被滤除,该文首先研究了模数滤波算法,并提出了一种基于最短子区间搜索的干涉相位模数估计算子对其进行改进,在进一步分析模数估计参数与相位分辨率之间关系的基础上,提出了一种局部相位中心随干涉相位质量自适应变化的中值滤波方法。该方法不仅克服了模数滤波导致的条纹边缘模糊问题,还解决了传统空域滤波进行一致性处理所造成的过滤波和欠滤波问题,而且具有较高的运算效率。最后通过对仿真和实测TerraSAR–X数据的处理和分析,验证了该方法的有效性。     

基于离轴显微干涉术的单幅干涉图相位求解（英文）

提出一种用于测量微结构表面形貌的离轴显微干涉术。该技术的实验装置为一个优化的马赫-曾德尔干涉仪。其特点为参考波是具有一定载频的倾斜波。该技术中应用CCD记录离轴显微干涉图,并用傅里叶变换方法对记录的干涉图在傅里叶面进行频谱滤波求解相位。不同于经典显微干涉术,离轴显微干涉图的载频较高,仅需单幅干涉图即可得到相位信息。因此该技术在测量中具有防振、快捷有效的特点。利用一个标准微台阶以及微孔阵列的形貌检测结果验证该技术的有效性,同时与轮廓仪的测试结果进行对比,证明结果一致。被测物也应用Mirau干涉显微镜进行测试,实验结果表明经典显微干涉图干涉信息载频不足,仅使用单幅干涉图不能得到正确相位,该组实验证明了离轴显微干涉术相对于传统显微干涉术的优越性。     

用于圆形口径光学元件的功率谱密度检测

光学元件加工质量的检测和评价是保证整个光学系统安全、正常运行的关键.波前功率谱密度(Power Spectral Density,PSD)能给出光学表面的空间频谱分布,反映高精度光学元件加工质量的特殊要求.在总结现有功率谱密度指标基础上,提出由于圆形口径的旋转对称性,可以采用径向波前功率谱密度来表征圆形口径光学元件波前频谱分布特征的方法,并给出了采用三坐标仪作为测试仪器测量圆形口径光学元件的波前功率谱密度时相应的数值计算方法.     

利用声光调制器进行错位外差干涉测量

一、前言 外差干涉测量法能测量高精密透镜象差,表面形状和形变、振幅、速度等。其频率彼此靠扰的波前相干涉而产生一电差频信号,差频信号的相位与两波前之间的光程差成正比。山于信号相位与参考信号同步,因而测量精度约为2π/100rad。可用移动光栅、旋转波片或超声光调制器作为频移器件。 利用光栅的错位干涉测量法已在Ronchi试验中用于测量透镜象差。现在又提出了错位外差干涉测量法,它利用移动光栅使待测波前产生频移和空间错位。这些错位外差干涉计用于自适应光学元件中的波前校正和镜面的形状测量。     

单幅干涉条纹图的高精度波面重建技术

结合莫尔条纹、傅里叶变换和数字相移技术实现了对单幅干涉条纹图的高精度相位计算和波面重建.首先,用计算机生成与被处理干涉条纹频率相近的数字相移条纹图,与实际干涉条纹图叠加得到相移莫尔条纹图;然后,利用傅里叶变换、双频滤波、傅里叶反变换和相移技术得到干涉条纹图的相位数据;最后利用波面拟合技术重构原干涉条纹图对应的波面形状.研究结果表明,该技术不仅消除了干涉仪硬件相移产生的非线性误差和滤波时的频谱移中误差,高精度获得了单幅干涉条纹图对应的波前,而且简化了系统的机械结构.同时,对环境的要求明显降低,特别适用于生产现场的检测.     

基于光学干涉法的光学元件表面粗糙度检测技术

为实现光学元件表面微小粗糙度的精准、详细检测,研究基于光学干涉法的光学元件表面粗糙度检测技术。该技术采用基于集成光学干涉成像技术对光学元件表面干涉成像,通过改进的Niblack二值化算法提取元件表面干涉图像条纹信息,并基于节点迭代的去毛刺方法细化处理干涉条纹,利用最小二乘方法拟合干涉条纹,获取最小二乘拟合直线得出评定基准,建立评定表面粗糙度的高度参数和间距参数的数学模型,完成粗糙度检测。测试结果显示:该技术干涉成像能力较强,生成的光学透镜元件干涉图像弧度与边缘较为清晰,可有效去除干涉条纹毛刺,检测光学元件表面粗糙度时的真正类率最大数值已达到1.0。     

专利

美国加州Hughes Electronics公司的A.A.Betin等人提出一种环路4波混合相位共轭反射镜的设计方案。小型环路相位共轭器是由一个非线性元件、光电二极管和光学增益介质组成。非线性元件前表面透射光,后表面反射光。在前表面和后表面之间是非线性光学介质,信号光束入     

基于相位测量法测量透射式相位光栅的表面形貌

建立了一套基于马赫-曾德尔干涉仪的测量系统,获得了透射式相位光栅的相位信息并推算出光栅的表面形貌。给出了相位测量法的基本原理,运用傅里叶变换法和相位解包裹技术,对实验系统采集的干涉图的相位信息进行处理并计算出光栅的高度、周期和底角等结构参数。结果表明,该测量方法和系统能够精确地测量光学相位元件的表面形貌,具有较高的实用价值。     

宽光谱范围干涉检验术

点衍射干涉仪的一种新技巧可使劳仑斯·伯克利实验室X射线光学中心的研究人员在可见光到X射线波长的宽光谱范围里精确测量光学元件。对简单系统所作的试验已显示非常优良的可重夏性。在普通点衍射干涉仪中，针孔由于使相干照明衍射成球面参考波前（图1），消除了参考表面的需要。含有针孔的半透明拥模安装在待检光学元件焦点附近。直接通过该针孔膜的光对检验光学元件照明，产生检验波前，该波前又与球面参考波前干涉。以后的条纹分析给出了有关检验表面质量的信息。这种普通设计有两个特有缺点。产生的参考波前的针孔限制了参考波强度，这…     

X-ray metrology for high-k atomic layer deposited HfxZr1−xO2 films

Hafnium-based dielectrics are the most promising material for SiO₂ replacement in future nodes of CMOS technology. While devices that utilize HfO₂ gate dielectrics suffer from lower carrier mobility and degraded reliability, our group has recently reported improved device characteristics with a modified Hf_xZr_1−xO₂ [R.I. Hegde, D.H. Triyoso, P.J. Tobin, S. Kalpat, M.E. Ramon, H.-H. Tseng, J.K. Schaeffer, E. Luckowski, W.J. Taylor, C.C. Capasso, D.C. Gilmer, M. Moosa, A. Haggag, M. Raymond, D. Roan, J. Nguyen, L.B. La, E. Hebert, R. Cotton, X.-D. Wang, S. Zollner, R. Gregory, D. Werho, R.S. Rai, L. Fonseca, M. Stoker, C. Tracy, B.W. Chan, Y.H. Chiu, B.E. White, Jr., in: Technical Digest - International Electron Devices Meet, vol. 39, 2005, D.H. Triyoso, R.I. Hegde, J.K. Schaeffer, D. Roan, P.J. Tobin, S.B. Samavedam, B.E. White, Jr., R. Gregory, X.-D. Wang, Appl. Phys. Lett. 88 (2006) 222901]. These results have lead to evaluation of X-ray reflectivity (XRR) for monitoring high-k film thickness and control of Zr addition to HfO₂ using measured film density. In addition, a combination of XRR and spectroscopic ellipsometry (SE) is shown to be a fast and non-intrusive method to monitor thickness of interfacial layer between high-k and the Si substrate.     

Students’ thoughts about the importance and costs of their mobile devices’ features and services

In recent years, handheld devices have become one of the fastest growing communication gadgets. Mobile technology is becoming widespread and research in this area is urgently needed. Using a survey instrument, the thoughts of male and female students regarding the importance and costs of mobile devices were investigated. It was found that students tend to consider the following features important: battery life, mp3 player, video camera, photo camera, storage memory, Bluetooth, design and elegance, clock, calendar, organizer and reminder. Also, they are eager to spend an amount of money so as their mobile device to support them. On average, both genders would pay extra money for such features. However, the majority of females think less of the price than males do. On the contrary, most of the respondents do not consider the following important: touch screen, voice commands, chat, teleconference, encryption and cryptography, common use of files, printing. Therefore, they would not spend any money for these features. Interested decision makers would try to increase their interest on such features. Moreover, all respondents appear to own a mobile phone while most of them do not have Internet connection at home. In general, some gender differences are found in the importance and costs of the mobile devices, but they are not statistically significant.     

Job schedulers for Big data processing in Hadoop environment: testing real-life schedulers using benchmark programs

At present, big data is very popular, because it has proved to be much successful in many fields such as social media, E-commerce transactions, etc. Big data describes the tools and technologies needed to capture, manage, store, distribute, and analyze petabyte or larger-sized datasets having different structures with high speed. Big data can be structured, unstructured, or semi structured. Hadoop is an open source framework that is used to process large amounts of data in an inexpensive and efficient way, and job scheduling is a key factor for achieving high performance in big data processing. This paper gives an overview of big data and highlights the problems and challenges in big data. It then highlights Hadoop Distributed File System (HDFS), Hadoop MapReduce, and various parameters that affect the performance of job scheduling algorithms in big data such as Job Tracker, Task Tracker, Name Node, Data Node, etc. The primary purpose of this paper is to present a comparative study of job scheduling algorithms along with their experimental results in Hadoop environment. In addition, this paper describes the advantages, disadvantages, features, and drawbacks of various Hadoop job schedulers such as FIFO, Fair, capacity, Deadline Constraints, Delay, LATE, Resource Aware, etc, and provides a comparative study among these schedulers.     

Progress in ZnO materials and devices

ZnO is a wide-band-gap semiconductor material that is now being developed for many applications, including ultraviolet (UV) light-emitting diodes, UV photodetectors, transparent thin-film transistors, and gas sensors. It can be grown as boules, as thin films, or as nanostructures of many types and shapes. However, as with any useful semiconductor material, its electrical and optical properties are controlled by impurities and defects. Here, we consider various important donor-type impurities, such as H, Al, Ga, and In, and acceptor-type impurities, such as N, P, As, and Sb. We also examine the effects of a few common point defects, including Zn interstitials, Zn vacancies, O vacancies, and complexes of each. The main experimental techniques of interest here include temperature-dependent Hall-effect and low-temperature photoluminescence measurements, because they alone can provide donor and acceptor concentrations and donor energies. The important topic of p-type ZnO is also considered in some detail.     

Thyristor Input-Protection Device Suitable for CMOS RF IC’s

Based on simulation results and accompanying analysis, we suggest a thyristor-type ESD protection device structure suitable for implementation in standard CMOS processes to reduce the parasitic capacitances added to the input nodes, which is very important in CMOS RF ICs. We compare DC breakdown characteristics of the suggested device to those of a conventional NMOS protection device to show the benefits of using the suggested device for ESD protection. The characteristic improvements are demonstrated and the corresponding mechanisms are explained based on simulations. Structure dependencies are also examined to define the optimal structure. AC simulation results are introduced to estimate the magnitude of reduction in the added parasitic capacitance when using the suggested device for ESD protection. The analysis shows a possibility of reducing the added parasitic capacitance down to about 1/45 of that resulting with a conventional NMOS protection transistor, while maintaining robustness against ESD.Jin-Young Choi was born in Seoul, Korea in 1956. He received the B.S. degree in electrical engineering from the Seoul National University, Korea, in 1979, and the M.S. and Ph.D. degrees in electrical engineering from the University of Florida, USA, in 1986 and 1991, respectively. In 1991, he joined Samsung Electronics Memory Division, Korea, where he was engaged in high-speed SRAM development. In 1992, he moved to the Hongik University, Jochiwon, Korea, where he is now an associate professor. His recent research interests include the high-frequency modeling of CMOS devices, CMOS RF circuit design, and analysis & design for ESD protection.Woo Suk Yang was born in Seoul, Korea in 1957. He received the B.S. degree in electrical engineering from the Seoul National University, Korea, in 1979, and the Ph.D. degree in electrical and computer engineering from the North Calorina State University, USA, in 1990. His doctorial research was in the area of signal processing. In 1990, he joined LG Electronics Co. Korea. In 1991, he moved to the Hongik University, Jochiwon, Korea, where he is now a professor. His recent research interests include the high-frequency modeling and various topics in signal processing area.Dongmin Kim was born in Korea in 1956. He received the B.S. and M.S. degrees in electrical engineering from the Seoul National University, Korea, in 1979 and 1984, respectively and the Ph.D. degree in ECE from the University of Michigan, USA, in 1996. Now, he is an assistant professor of the Hongik University, Jochiwon, Korea. His recent research interests include circuit design and analysis.Youngju Kim was born in Seoul, Korea in 1957. He received the B.S. and M.S. degrees in electrical engineering from the Seoul National University, Korea in 1980 and 1985, respectively and the Ph.D. degree in electrical engineering from the Polytechnic University of New York, USA, in 1995, respectively. In 1996, he joined the Hongik University, Jochiwon, Korea, where he is now an assistance professor. His recent research interests include the RF circuit design and LIN wireless systems.     

智能语音操控在广电端到端的系统设计及应用

在数字化中国的大背景下,在公司个人宽带与互动电视在线交费用户均突破300万户的情况下,为解决我们的用户总找不到自己喜欢看的节目,记不住频道名称和喜欢的节目,提升公司竞争力。通过对前端的点播系统、AAA系统、EPG系统、PORTAL系统、ISMP系统、媒资系统、机顶盒终端的功能进行剥离、整合和详细设计,最后完成终端用户语音操控电视直播、点播、时移、回看、页面操控、系统设置,并支持普通话和四川话方言的目的。达到提升用户体验,增加公司竞争力,促进业务的发展。系统试运行后,用户体验效果得到很大提升,完全达到预期设计目的。     

谈对电子元器件企业设计开发过程中“六性”的审核

通过对电子元器件企业＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂的审核,帮助企业识别＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂,认识＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂在产品设计开发中的重要性,实现产品的＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂指标。     

卫星通信组呼业务MAC层研究

组呼通信在指挥调度中有着重要作用,而在一些地面没有基站的地方,就无法正常使用。卫星通信具有无视地形,通信范围广,不易受陆地灾害影响,易于建设等优点。把卫星通信和组呼通信结合在一起的卫星组呼通信技术兼顾两者的优点,能更好的发挥指挥调度这一作用。当前卫星组呼通信采用固定频率方式,组呼成员在一个频率下进行通信,这种方式实用性不好。本文研究的是移动卫星组呼,在GMR-1系统的基础上研究了卫星组呼通信中MAC层的功能,提出了MAC-Ready-Gcc、MAC-Dedicated-Gcc这两个为了支持组呼的状态,并针对在MAC层发生的PTT竞争提出了一种回退策略。     

A Progress Report on Metal–Sulfur Batteries

Nonaqueous conversion‐reaction sulfur chemistry has been attracting increasing attention over the past decade for the development of next‐generation lithium‐based batteries. Li–S batteries are currently approaching a nexus stage from lab‐scale experiments to possible pragmatic applications. Inspired by the success of Li–S chemistry, other metal–sulfur batteries with a variety of metallic anodes, such as sodium, potassium, magnesium, calcium, and aluminum, have also started to attract attention. In comparison to lithium, Na, Mg, Al, K, and Ca are naturally more abundant and affordable. The Na‐S, Mg‐S, Al‐S, K‐S, and Ca‐S battery systems provide a great potential for improving the volumetric energy density of sulfur‐based batteries. The multivalent metal‐sulfur systems, Mg‐S, Al‐S, and Ca‐S, offer better safety features as well. However, the research and development on Na‐S, Mg‐S, Al‐S, K‐S, and Ca‐S batteries is far behind the Li–S system due to many critical challenges. In this progress report, the fundamental principles of various metal–sulfur chemistries are first presented and compared. Then, the historical progress, recent advances, and key challenges of the Li–S, Na‐S, Mg‐S, Al‐S, K‐S, and Ca‐S systems are summarized and discussed. Finally, future efforts and directions for both the fundamental and practical research are prospected.     

VoIP技术--语音和数据的集成

介绍了VoIP(Voice over IP)的基本组成构件即网关(Gateway)、网守(Gatekeeper)的概念和用途。讲述了语音在IP网上传输的基本原理，语音和数据、数据和IP包之间的转换和传送过程。在H．323协议栈的基础上详细讲述了H．248，H．225，H．245等通信协议和语音编码G．729，G．23l，G．7ll等协议。最后对VoIP的语音服务质量作了较为详细的阐述。