多级染料激光放大器中激光增益与放大自发辐射强度的理论研究

利用激光增益和放大自发辐射 (ASE)理论 ,对不同条件下的染料激光放大器的激光增益和ASE强度进行了数值计算。分析了当入射光强远小于和大于有效饱和光强时 ,激光增益和ASE强度与入射光相对强度的关系 ,讨论了在两种条件下ASE系数以及染料池端面反射系数对激光增益和ASE成分的影响。最后利用这些结果 ,对连续激光的多级染料放大系统的优化设计进行了讨论。     

铜蒸气激光泵浦的染料激光器中的ASE分析

对铜蒸气激光器横向泵浦的染料激光器中的ASE特性进行了研究。在理论上,考虑染料光强的时间、空间变化关系和光谱分布以及上能级粒子数的时间、空间变化,用计算机进行差分求解,得到ASE光强、光谱分布随泵浦光强的变化,得出了不同波长ASE光的脉冲宽度的不同结果,对增益的空间分布也进行了计算。在实验上,用平均功率5W的铜蒸气激光器泵浦R6G的酒精溶液,染料在染料盒中快速流过泵浦区。测出ASE强度随泵浦光的变化关     

一种新型脉冲染料激光振荡器

本文提供了脉冲染料激光振荡器一种新的运转配置方式，其主要特点是：利用染料池入射窗内壁对振荡光束的反射和对输出光束的耦合，使它们偏离开染料激活区轴线方向，从而能有效地抑制激光输出中的ASE背景；同时，利用准环形振荡，提高了振荡器的效率。     

SCDL振荡放大系统单模及双模运转的特性

本文报道对短腔染料激光(SCDL)振荡放大系统单模工作及双模工作时输出的光谱特性和运转性能的研究,观测了放大器放大自发发射(ASE)及系统调谐特性,讨论了系统ASE及其不稳定性等问题及其解决的措施。     

CuCl激光器泵浦的高效率窄线宽波导染料激光器

报道一台效率高、线宽窄的波导染料激光器;线宽4GHz,效率12.5％,ASE宽带背景为4.7％,发散角为3mrad。对几种染料谐振腔的输出特性进行了比较。     

振放交叠独立调谐的双波长染料激光器

报道了一种新型的双被长染料激光器，它的两个波长的振荡和放大通过一块半反镜的耦合而相互交叠，具有压低ASE背景和提高激光效率等多方面的优点。     

行波放大自发辐射产生超短光脉冲的研究

我们采用泵浦能量具有梯度分布的横向泵浦方案,以N_2激光(700ps)为泵浦源,获得约50ps的染料光脉冲输出,以锁模Nd:YAG倍频光(46ps)作泵浦源,获得8～15ps光脉冲输出。用条纹照相机和光学多道分析器测量了脉冲波形和光谱。实验研究了激发长度、染料浓度和激发能量等参数对光脉冲宽度的影响,比较了行波ASE和非行波ASE的波形和光谱。     

一种新型结构的染料激光振荡器的优越性

本文提出一种新型结构的染料激光振荡器,它有效地抑制了激光输出中的ASE背景。振荡器采用准环形振荡,能获得高效率激光输出。     

窄带、高光谱纯度、高效率的染料激光器

我们研制了用XeCl准分子激光器泵浦的染料激光器振荡一放大系统,获得了700MHz的单纵模线宽,13％的能量转换效率,ASE噪声仅占激光成份的千分之几的优良性能。     

染料放大器的ASE和飞秒脉冲放大

分析了染料放大器(DLA)的放大的自发辐射(ASE)的分布、上能级以及三重态粒子数分布。用数学方法模拟计算了泵浦作用时非饱和情形下染料分子的储能和飞秒脉冲的放大。我们认为,设计一个染料放大器必须考虑三重态积累对分子储能的影响。用调Q倍频Nd∶YAG脉冲同步泵浦染料二级放大器放大飞秒脉冲,得到的第一、二级放大倍数分别为1000和60,对于第一级放大,计算结果与实验结果基本相符。     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

胆小管超微细胞酶学研究

以电镜细胞化学的方法,观察了小鼠胆小管酶的分布。观察的12种酶中,NDPase和G6Pase三种酶分布于胆小管微绒毛;AlPase、Na~+-K~+ATPase、Mg~(++)-ATPase、Ca~(++)-ATPase、CMPase、ACase和5＇-Nase等7种酶分布于胆小管微绒毛,也分布于肝细胞邻接面细胞膜和Disse间隙微绒毛;ACPase、细胞色素氧化酶以及线粒体ATPase不分布胆小管微绒毛,也不分布Disse间隙微绒毛和肝细胞膜。据信,胆小管微绒毛上的酶参与胆汁成份的转运,提供转运所需能量以及还可能与某些代谢过程有关。本实验中磷酸水解酶类使用的铈基法及亚铁氰化钾半还原的锇酸后固定法,效果优于铅法。     

应用伪随机码的EAS系统

在通信系统中，伪随机码应用十分广泛，其优点是抗干扰能力强，保密性好。在比较两种伪随机码产生方法的基础上，分析了应用伪随机码的EAS(Electronic Article Surveillance)系统的优点：抗干扰能力强和多系统协调工作性能好。同时，提出一种以伪随机特征码为纽带的多个EAS系统一起工作的协调方式。然后，通过对现有EAS系统不足点的分析，提出了新的检测信号有效性的判断依据，即信号的测量值与平均值的偏差是符合高斯分布的，以及相应的评判方法，即计算信号测量值与平均值的偏差，如果测量偏差大于某个城值，则触发一个报警。由此，进一步详细阐述了将伪随机码技术应用于EAS系统的具体方法及其抗干扰能力。     

电磁兼容检测实验室测试系统相符性比对研究

电磁兼容测试结果与检测实验室可靠性程度直接相关,检测实验室自身质量是保证电磁兼容测试结果准确性先决条件,检测实验室测试系统相符性则成为电磁兼容系统性能评估中需要考虑的关键内容和重要指标。因此,检测实验室测试系统相符性比对是实现电磁兼容系统评估研究的基础工作之一。本文首先针对电磁兼容检测实验室测试系统相符性比对的特点,结合自己几年来的测试实践论述了电磁兼容检测实验室测试系统相符性对比方案,然后提出了具体的案例同时进行了详细的分析,最后总结出了影响电磁兼容检测实验室测试系统相符性因素,整个案例和分析过程及结果可作为电磁兼容检测实验室测试系统相符性比对的手段和依据,具有重要的现实指导意义。     

大掺量矿渣复合胶凝材料的硬化浆体形貌特征

通过扫描电镜观察了大掺量矿渣复合胶凝材料在不同水化龄期的硬化浆体形貌,并与水泥硬化浆体形貌进行对比,研究了矿渣在复合胶凝材料中的水化性能与硬化浆体形貌特征的关系.结果显示:大掺量矿渣复合胶凝材料水化早期的浆体结构比水泥浆体结构疏松,28天的浆体结构比水泥浆体结构致密.水化早期,矿渣颗粒被水泥水化产物包裹,与水泥浆体界面薄弱;水化后期,矿渣颗粒的水化产物与水泥水化产物紧密结合,颗粒与水泥浆体的界面牢固.     

Towards Mobile Ubiquitous Service Environment

In this article we present a perspective on future vision of mobile communications and services which is referred to as Mobile Ubiquitous Service Environment (MUSE). Based on analysis of wireless communications and services, we exploit a conceptual model for MUSE via a top-down approach. The conceptual model consists of three major elements: Terminal Service Environment (TSE), Network Service Environment (NSE) and User Identity (UID). The concept of Always the Best Experience (ABE) is addressed as the hinge in design and development such that the user-centric services could be provided automatically and intelligently in the future diverse wireless world Based on these, we further discuss the issues on design and implementation of architecture of future wireless communication system. Requirements for architecture brought by the new features of MUSE are listed. Moreover, we also address several tradeoffs that should be taken into consideration in design. Finally, the deployment challenges for MUSE, such as reflectiveness of system, security and privacy, as well as peer-to-peer AAA are predicted.Ji Yang received PhD degree on Circuit and System, Bachelor degree on Telecommunication Engineering from Beijing University of Posts and Telecommunications (BUPT) in 2002 and 1993 respectively. Currently, he is an associate professor of BUPT, chief technical supervisor of Wireless Technology Innovation Institute, and vice manager of MTlab of Sino-Germany Software Institute. He leads the research on service and application in Future Forum in China. He also made much contribution to the China Communication Standardization Association (CCSA), including the vision of future Mobile Ubiquitous Service Environment, architecture of future B3G mobile terminal, etc. His research interests include architecture design for mobile ubiquitous networks, theory of self-organization, etc.Zhang Ping is now the professor of Beijing University of Posts and Telecommunications and director of Wireless Technology Innovation (WTI) Institute, BUPT. He has also served on the senior member of C3G Group, China MOST 863 future mobile communication FuTURE project, vice-chairman of China FuTURE Forum, and member of Vision Committee of World Wireless Research Forum(WWRF), he was vice chair of WWRF in 2005. He is also invited as the consultants for many domestic and oversea communication companies. He is very active on the international research activity on Beyond 3G area. He also participated in several European projects such as E2R and MOCCA. Until now, he has published 6 books, around 400 publications in journals and conferences in the area of telecommunications. His main research interests are theory and applications in wireless communication area. He was awarded by government, city of Beijing and Ministry of Information Industry several times for his great contribution to the industry and research activity in China.Hu Zheng is a PH.D candidate in mobile communications engineering in Wireless Technology Innovation Institute (WTI) at Beijing University of Posts and Telecommunications (BUPT). He received B.S degree from Nanjing University of Posts and Telecommunications in 2002, majoring in computer communications engineering. He currently works on serivce aspects of mobile ubiquitous communication system with focus on design and performance evaluation of interaction protocols and services in self-organized service environment.Wang Xu received the B.Tech. degree in electronic engineering from Beijing Polytechnic University (now named as Beijing University of Technology), Beijing, China, in 2002. Now he is working for his Ph.D. degree in Wireless Technology Innovation (WTI) Institute, Beijing University of Posts and Telecommunications (BUPT). His current interests include wireless communications in personal area, ad hoc networks and peer-to-peer system.Li Yinong received the BS degree major in Telecommunication Engineering in 1993 from Beijing University of Posts and Telecommunications, the MS degree and PhD degree major in Telecommunication and Electronic System in 1995 and 2003 from the Beijing University of Posts and Telecommunications. He is currently a lecture of STE (School of Telecommunication Engineering) of BUPT. His main research interests include service modeling, service composition approach, and intelligent service. In BUPT, he has given several lectures to both graduate and undergraduate students such as Information Theory, Speech Recognition, Pattern Recognition and Artificial Intelligence.     

Instantaneous envelope and phase extraction from real signals: Theory,implementation, and an application to EEG analysis

This paper presents a unified treatment of various important signal processing techniques for the extraction of the instantaneous envelope and phase of a real signal. These techniques include Complex Demodulation, Hilbert Transformation, In-Phase and In-Quadrature Filtering, Phase-Locked Loop Demodulation, and Peak Amplitude and Zero-Crossing Detection. The salient points in the mathematical theory and implementation of these techniques are outlined, as well as their interrelationships via the theory of analytic signals. The advantages and limitations of each of these techniques are elaborated upon, and Complex Demodulation is shown to be the most effective and flexible method from an implementation point of view. The relation of the above techniques to Fourier spectrum analysis is elucidated, and an example is presented of applying Complex Demodulation for the quantification of time nonstationarities in the electrographic morphology of an EEG waveform.     

米酵菌酸对小鼠肝和心肌细胞毒性作用的超微结构研究

目的：观察米酵菌酸对小鼠肝、心肌细胞毒性作用的超微结构改变，探讨米酵菌酸中毒的机理，方法：小鼠腹腔注射不同剂量的米酵菌酸，2h后取其肝和心肌组织，通过电镜观察其细胞超微结构的改变，结果：电镜下可见肝细胞和心肌细胞的线粒肿胀，内嵴断裂，模糊或消失，基质局部或全部空亮，呈囊泡样变，偶见其中含髓样小体，上述线粒体内嵴和膜结构的病变随米酵菌酸剂量的增加而加重，结论：米酵菌酸对小鼠肝、心肌细胞毒性作用以线粒体的损伤较为突出，因此我们认为，线粒体内膜的破坏造成线粒体的功能障碍，影响细胞呼吸，使细胞缺氧导致小鼠中毒死亡。