Mechanism of silicon film deposition in the RF plasma reduction of silicon tetrachloride

Plasma-chemical reduction of SiCl₄ in mixtures with H₂ and Ar has been studied by optical emission spectroscopy (OES) and laser interferometry techniques. It has been found that the Ar:H₂ ratio strongly affects the plasma composition as well as the deposition (r _D) and etch (r _E) rates of Si: H, Cl films and that the electron impact dissociation is the most important channel for the production of SiCl_x species, which are the precursors of the film growth. Chemisorption of SiCl_x and the reactive surface reaction SiCl_x+H–SiCl_(x–1)0+HCl are important steps in the deposition process. The suggested deposition model givesr _D [SiCl_x][H], in agreement with the experimental data. Etching of Si: H, Cl films occurs at high Ar: H₂ ratio when Cl atoms in the gas phase become appreciable and increases with increasing Cl concentration. The etch rate is controlled by the Cl atom chemisorption step.     

激光引发二氟卡宾与烯烃的反应

近十年来,激光引发一氯二氟甲烷红外多光子解离和激光敏化反应的研究非常活跃,但大部分工作都集中于解离机制及同位素分离,而对CF_2HC(?)多光子解离产生的二氟卡宾     

In-gel deglycosylation of sodiumdodecyl sulfate polyacrylamide gel electrophoresis-separated glycoproteins for carbohydrate estimation by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Mass determination by mass spectrometric methods (electrospray ionization mass spectrometry (ESI-MS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS)) of sodiumdodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)-separated proteins is a well known procedure and reliable protocols are available. In our efforts to use the established methods to determine the molecular mass of the disulfide bridged, heterodimeric glycoprotein GP3 and to determine the carbohydrate content of each protein subunit we developed an in-gel chemical deglycosylation method. For this purpose we established experimental conditions that allow maximum extraction of the high molecular mass protein subunits and developed a routine method to apply the HF-pyridine deglycosylation protocol to proteins isolated from polyacrylamide gel pieces. The novel protocol and extraction procedure described can be used to analyze O-glycosylated proteins up to 150 kDa after SDS-PAGE separation.     

Degradation in gain for a free electron laser amplifier due to electron momentum spread

A finite spread in axial momentum for the electron beam in a free electron laser amplifier is shown to decrease the small-signal gain. For millimeter and sub-millimeter wave amplifiers, where exponential growth dominates the gain, it is shown that the gain is approximately 3 db below that for a cold beam if the relative momentum spread (u/u)_1/2 = (G_o/248)^1/2 (_o/L), where G_o1 is the gain in db for the cold-beam case, _o is the magnetic wiggler period, and L is the amplifier length. Exact numerical examples are given for representative FEL amplifiers at 35 and 550 GHz.This research was sponsored by the U.S. Office of Naval Research, and by the U.S.-Israel Binational Science Foundation.     

激光热致相变核-壳微胶囊的合成与性能

以甲基丙烯酸甲酯作为主要的核单体，甲基丙烯酸缩水甘油酯作为壳单体，叔胺盐作为壳的改性剂，合成了平均粒径为55nm具有激光热致相变性能的核壳微胶囊。用红外光谱对其结构进行了表征；用透射电镜观察了微胶囊形貌；用示差量热分析法、热重分析法测定了热性能、接触角仪测定了相变前后的亲水性，探讨了对相变效果的影响因素。核聚合物的玻璃化转变温度为56.2℃，壳聚合物的玻璃化转变温度为85.3℃；该微胶囊感激光后发生相变，接触角由初始的20°变为93°。     

四台单模激光的混沌强度和位相同步

运用数值模拟的方法对四台空间相互耦合的单模Nd：YAG激光器系统的动力学行为进行了研究，讨论了激光系统中的输出强度，并利用分析信号位相和高斯位相变换对激光系统中强度的位相进行了分析。数值研究表明，激光强度存在混沌同步，且强度的混沌同步是通过其位相同步来实现的。通过对功率谱和李雅普诺夫指数的分析，可以确信所研究的激光系统处于混沌状态。     

光子晶体光纤及其激光器

光子晶体光纤(PCF)与普通光纤相比有其优秀的特性，如单模特性、色散特性以及非线性特性等。简述了光子晶体光纤的基本结构及其优点，并介绍了利用光子晶体光纤制作光子晶体光纤激光器及大功率光纤激光器方面的进展。     

激光皮肤治疗技术研究

利用激光对病损组织进行修复的皮肤整形过程,激光对皮肤的治疗,不仅可治愈各种胎记,也能治疗雀斑、纹身、眼眉色斑及鲜红斑痣等多种皮肤病,可为不同年龄的患者,包括老年人与婴儿作治疗.能够解决色素增生类和血管类皮肤病,改善或恢复先天造成的容貌和外表缺陷.激光对皮肤的治疗技术与传统的疗法相比具有出血少、痛苦小、手术质量高、手术时间短、疤痕少和复发率少等优点,是一种科学、快速、安全有效的美容方法.     

多重命中弹药激光同步起爆技术探讨

该文提出一种新型火炮引信技术思想，阐述了研究弹药多重命中体制的意义。探讨激光同步起爆技术的优点，计算了激光发射器功率和点火火药的能量匹配关系，计算和实验工作为激光同步起爆技术的进一步研究奠定了基础，该命中体制的应用为提高小口径弹药的威力提供新的思路，也可应用于其它武器系统中。