贵州凯麻高等级公路峨山冲段新开石质边坡绿化调查

对贵州凯麻高等级公路峨山冲段新开石质边坡绿化进行了调查,并与边沿植被及未绿化地进行了比较,认为在陡峭山岩快速绿化的技术,在治理新开石质边坡生态方面具有好的效果,能在短期内快速绿化、改变边坡生态受破坏的状况,对同类型地段的生态治理及绿化有好的借鉴意义,值得大力推广.     

裂变碎片靶室在直接测量重Λ超核寿命中的应用

介绍了一种新的直接测量重超核寿命的方法. 并对其中用到的一个重要探测设备——裂变碎片靶室——在托马斯.杰斐逊国家实验室用²⁵²Cf放射源进行了测试. 该靶室的单模块时间分辨率为～163ns. 在此分辨率的基础上, 计算机模拟表明用此方法测到的超核寿命误差将在9.6ps左右.     

PKI技术在信息安全中的应用

介绍了PKI(PublicKeyInfrastructure,公钥基础结构)的基本概念、基本组成.根据PKI的基本原理,采用RSA算法对传输的信息进行加密,并利用公钥服务器来对公钥进行管理与维护,构建了完整的安全体系使得资源共享和信息传递安全得到充分保证.讨论了MicrosoftPKI的系统流程和程序实现,以及PKI技术在信息安全中的应用.     

ZrO2/SO2-4类固体超强酸在有机合成中的应用进展

简要介绍了ZrO2/SO2-4-类固体超强酸的制备及其改性;综述了近年来此类催化剂以其独特的不溶性、酸性、活性、选择性在有机合成反应中的广泛应用,参考文献40篇.佑     

Influence of the randomly varying domain length of quasi—phase—matched crystals on quadrature squeezing performance

During the fabrication of quasi-phase-matched(QPM) devices,errors of periodic structure are usually inevitable.The errors result in the deviation of the actual periodic domain length from the theoretical value.In this paper,we numerically analyse the influence of errors on the quadrature squeezing performance of a degenerate optical parametric amplifier consisting of QPM devices.It is shown that errors significantly degrade the squeezing degree of the quadrature squeezed light.Due to the presence of the errors,the relative phase between the signal and the pump field for obtaining the maximum squezing depends on the propagation distance of light in the crystal and the pump power.     

强化设备管理 创造运行佳绩

本篇主要介绍了安钢第一轧钢厂设备零故障管理的具体实施措施，促进了设备管理水平再上新台阶，保证了生产的顺利进行。     

Experimental measurement of radiation dose in a dedicated breast CT system

Radiation dose is an important performance indicator of a dedicated breast CT (DBCT). In this paper, the method of putting thermoluminescent dosimeters (TLD) into a breast shaped PMMA phantom to study the dose distribution in breasts was improved by using smaller TLDs and a new half-ellipsoid PMMA phantom. Then the weighted CT dose index (CTDI_w) was introduced to average glandular assessment in DBCT for the first time and two measurement modes were proposed for different sizes of breasts. The dose deviations caused by using cylindrical phantoms were simulated using the Monte Carlo method and a set of correction factors were calculated. The results of the confirmatory measurement with a cylindrical phantom (11 cm/8 cm) show that CTDI_w gives a relatively conservative overestimate of the average glandular dose comparing to the results of Monte Carlo simulation and TLDs measurement. But with better practicability and stability, the CTDI_w is suitable for dose evaluations in daily clinical practice. Both of the TLDs and CTDI_w measurements demonstrate that the radiation dose of our DBCT system is lower than conventional two-view mammography.     

开放的梯型三能级系统中自发辐射诱导相干对无粒子数反转激光的影响

研究表明,在开放的梯型三能级系统中,无论是否考虑非相干泵浦,考虑自发辐射诱导相干（SGC）时系统产生的无粒子束反转激光（LWI）总是明显大于不考虑SGC时的情况.并且,SGC的强度在一定范围内时,系统在无非相干泵浦场的情况下会产生比有非相干泵浦时更大的无反转增益,而相应的封闭系统在无非相干泵浦场时对任意强度的SGC都无法产生增益.     

激光二极管端面纵向泵浦Nd:YVO_4激光器的热效应研究

针对激光二极管端面纵向泵浦Nd:YVO4激光器,本文理论和实验详细研究了Nd:YVO4晶体的热透镜效应。在激光二极管的中心波长分别为808nm和880nm及分别采用单端端面纵向泵浦和双端端面纵向泵浦结构情况下,实验测量了Nd:YVO4晶体的热透镜焦距,实验结果和理论预测基本吻合。同时在泵浦功率60W时获得了18.8W的连续基横模激光输出。     

连续变量多模压缩态光场

连续变量压缩态光场的制备在量子光学和量子信息科学领域具有重要的地位,连续变量多模压缩态光场在多维量子信息传输、量子计算以及高精细度测量等方面存在着潜力巨大的应用前景。本文介绍了该方面的研究现状和国际动态。