CCD狭缝摄象

在过去的几十年中,各靶场已广泛应用狭缝摄影对种种飞行弹丸的多项重要技术参数进行测试,它在许多测试项目中应用的有效性、广泛性和经济性已被人们所肯定。据报道,在国外的一些靶场所进行的发射试验中,狭缝摄影机曾占全部测试设备中所使用的摄影仪器的百分之九十,这是因为狭缝摄影有其独特的、其它方法不可比拟的优点。     

基于LDAP协议实现统一的网络管理研究

基于网络上信息存储方式的不统一及其所面临的困难 ,结合复旦大学校园网的特点 ,在深入研究LDAP协议的基础上 ,给出了一套跨协议认证的解决方案 ,提出了关于同步问题的两个模型和基于CSN方法的实现办法     

Simplified analytic solutions and a novel fast algorithm for Yb-doped double-clad fiber lasers

In this paper, continuous wave Yb³⁺-doped double-clad fiber lasers (DCFLs) with linear-cavity are investigated theoretically and numerically using the rate equations. Under the steady state conditions, the simplified analytic solutions of Yb³⁺-doped DCFLs under considering the scattering loss are deduced in the strongly pump condition. Compared with the known analytic solutions in published literatures, our analytic solutions are more accurate, especially, at higher reflectivity of output mirror. In addition, a fast and stable algorithm based on the Newton-Raphson method is proposed to simulate numerically Yb³⁺-doped DCFLs. The results by simplified analytic solutions are in good agreement with those by the numerical simulation. Moreover, we have performed the optimization of an Yb³⁺-doped DCFL using the simplified analytic solutions and the numerical simulations, respectively.     

利用富铈混合稀土改善工业纯铝中富铁相形貌的研究

利用金相分析方法研究了富Ce混合稀土变质对含不同Fe量的工业纯铝的组织和其中富铁相形貌的影响。试验结果表明,随着Fe含量的增加,富铁相由弥散细小的颗粒状向短棒状、长针状转变;富Ce混合稀土变质使铝中的富铁相由长针状变为弥散细小的颗粒状。随着稀土含量的增加,-αAl晶粒逐渐细化,富铁相尺寸及数量逐渐减小。添加0.5%稀土时,-αAl晶粒细化效果最佳,而且富铁相呈细小颗粒状均匀分布在-αAl基体的晶界处。本文还对稀土改善富铁相的机制进行了分析。     

Homoclinic and Periodic Orbits Arising Near the Heteroclinic Cycle Connecting Saddle-focus and Saddle Under Reversible Condition

In this paper, we study the dynamical behavior for a 4-dimensional reversible system near its heteroclinic loop connecting a saddle-focus and a saddle. The existence of infinitely many reversible 1-homoclinic orbits to the saddle and 2-homoclinic orbits to the saddle-focus is shown. And it is also proved that, corresponding to each 1-homoclinic （resp. 2-homoclinic） orbit F, there is a spiral segment such that the associated orbits starting from the segment are all reversible 1-periodic （resp. 2-periodic） and accumulate onto F. Moreover, each 2-homoclinic orbit may be also accumulated by a sequence of reversible 4-homoclinic orbits.     

Eu3+离子在微晶玻璃研究中的探针作用

制备出单掺Eu3+离子的氟氧化物玻璃陶瓷系列样品,利用Eu3+离子作为荧光探针,通过热处理前后Eu3+离子发射光谱中电偶极子跃迁与磁偶极子跃迁强度比值的变化表征在玻璃材料中微晶是否形成,分析了Eu3+离子荧光发射谱中电偶极子跃迁与晶体场对称性的关系,进一步表征了稀土离子所处微晶晶格场的变化.     

由大学多媒体教学实践所引发的深入思考

多媒体技术是物理教学良好的辅助工具，多媒体技术的应用为大学物理教学开辟了一片广阔天地。它能大大增加物理教学的信息量，图形形象直观、生动活泼，有着传统教学无法比拟的优势，但是，多媒体技术使用不当也会给物理教学带来一些负面影响。     

High longitudinal selectivity of shifting multiplexing in volume holograms

High longitudinal selectivity of the shifting multiplexing with spherical reference wave is proposed and demonstrated. A simplified method based on wave optics is used for calculating the selectivity, and the result fits well the experimental measurement. Under the paraxial condition, a simple formula for the longitudinal selectivity is introduced. With use of an object lens with effective NA=0.817, we obtain that an FWHM of selectivity is as small as 1 μm.     

最有效的相容剂是两嵌段还是多嵌段聚合物？

采用Monte Carlo模拟方法研究了多嵌段聚合物在A／B／嵌段聚合物三组份体系作为相容剂使用的有效性．占总体积19％的A组份在体系中为分散相．模拟结果显示了两嵌段和多嵌段聚合物在界面上的聚集行为,以及如何影响这个不相容体系的相形为．两嵌段聚合物趋于直立在相界面上,而多嵌段聚合物更容易横跨在相界面上并占据较大的界面积．从而导致多嵌段聚合物更有效的阻止体系相分离的发生．