分组网与ISDN互连的性能分析

本文研究分组交换数据网与ＩＳＤＮ互连的性能分析，文中考虑了分组肉与窄带ＩＳＤＮ和宽带ＩＳＤＮ互连时信关所应完成的功能，分别给出了两种情况下的信关排队模型；在信关存储容量分别为有限和无限的情况下，对两种模型进行了求解，给出了阻塞概率和平均延迟的表达式。对于与Ｂ－ＩＳＤＮ互连的情况，提出了用开关确定性过程来描述输出排队的分组到达流，并提出了一种小时隙方法分析ＳＤＰ／Ｄ／１排队。     

非均匀有耗媒质部分参数的重建

在高频部分，通过用Ｗｅｎｔｚｅｌ—Ｋｒａｍｅｒｓ—Ｂｒｉｌｌｏｕｉｎ—Ｊｅｆｆｅｒｙｓ（ＷＫＢＪ）解作为内场近似，本文证明了有耗非均匀媒质的反射系数在复平面上的轨迹是个圆。根据不同入射角度、不同极化的高频反射系数圆的圆心与半径，可以重建出有耗媒质的部分关键参数。本文方法同时适用于已知复反射系数谱和仅知反射系数振幅情况。文中给出具体重建实例。     

Nd：MgO：LiNbO3晶体的荧光光谱及其双晶体腔内互倍频实验

采用激光感生荧光技术测量了Ｎｄ：ＭｇＯ：ＬｉＮｂＯ３晶体的偏振荧光光谱，简要地说明了Ｎｄ：ＭｇＯ：ＬｉＮｂＯ３双晶体腔内互倍频的基本原理，并在实验中用染料激光作泵浦源实现了其双晶体腔内互倍频运转；得到５４３ｎｍ横模倍频绿光单端输出约ＹＭＷ，腔前泵浦阈值约３８ＭＷ，总转换效率约为１．３％。     

分散图象压缩的遗传算法

基于分形和PIFS函数的特点，提出一种改进的遗传算法用于分形压缩分块的定义域匹配搜索算法。该方法克服了原来分形图象压缩中分类匹配算法固有的局部最优性和随机搜索的缺点，是一种具导引的全局优化的搜索算法。分析和实验表明，该方法的图象压缩比高，解码质量好，若应用遗传算法的并行性，其编码速度也得到提高。     

荧光波长对共焦显微镜成像特性的影响

导出了共焦显微镜中不同荧光波长情况下的荧光功率传输函数、三维脉冲响应函数（3D－PSF）和三维光学传递函数（3D－OTF）。结果表明，不同的荧光波长对共焦显微镜的空间截止频率、分辨率、光学传递函数存在明显的影响。当激发波长与荧光波长的比值下降到一定程度时，可以看到明显的失锥现象。     

几种N-取代马来酰胺酸辅酶模型的核磁共振研究

我们对8种N-取代马来酰胺酸辅酶模型与不同类型的亲核试剂反应后生成的产物进行了¹H、¹³C NMR的研究, 测得¹H、¹³C谱化学位移,研 究探讨其规律性, 并测试了IR谱和元素分析.     

Influence of lattice self-heating and hot-carrier transport ondevice performance

As device technologies improve, the traditional drift-diffusion transport model becomes inadequate to predict the performance of state-of-the-art semiconductor devices. The reasons are believed to be the larger field and field gradient inside advanced devices which cause lattice heating and hot carrier nonlocal transport phenomena. For more accurate prediction on device performance, a new device simulator capable of full thermodynamic simulation was developed. The carrier and carrier energy transport equations are directly derived from the Boltzmann transport equation, and the energy transfer among electrons, holes and crystal lattice takes into account most of the possible mechanisms. This simulator was used to simulate the DC behavior of a BJT and a half-micron NMOS. The simulation results show that for advanced devices, not only the drift-diffusion model becomes inadequate, but including only one of the two thermal effects results in error in simulated device characteristics     

数字混沌扩频序列的盲估计

混沌序列具有非线性、宽带类噪声、大的码族、任意长的周期且容易产生的特性,因此在扩频通信系统中很有实用价值。本文将文献[1]中对伪随机扩频序列盲估计的方法推广应用到混沌扩频通信中,并对其不足提出了改进方法。在只知道扩频码周期而无其它任何先验知识的条件下,利用特征值分析的方法可以对数字混沌直扩序列进行盲估计,仿真实验证明了该方法的有效性。     

动态分组传输技术(DPT)性能分析

简要介绍动态IP光纤技术DPT的传输机制及相关的空间复用协议内容,同时分析DPT的主要特点,并与其他技术如ATM,POS等进行对比,说明DPT在大型IP网络应用中的优势.     

Synthesis of Nearly Monodisperse Iron Oxide and Oxyhydroxide Nanocrystals

Uniform magnetite, hematite, and goethite nanocrystals were prepared through an attractive method based on an oleic acid/alcohol/water system. By adjusting the synthetic parameters (base concentration, alcohol content, categories of alcohols, etc.), the controlled synthesis of uniform magnetite, hematite, and goethite nanocrystals can be easily achieved. Detailed investigations on the effect of the experimental parameters on the morphology of the final products and the phase transitions among the magnetite, hematite, and goethite phases were carried out. Finally, a method of doping other metal ions into magnetite was developed and the magnetic properties of magnetite doped with different metal elements were studied.