像平面式干涉成像光谱仪光程差分析与计算

像平面式干涉成像光谱仪的光程差(OPD)线性度与光谱及图像重建精度直接相关。分析了光程差产生原理,通过分别对单个像面的正离焦及负离焦部分光程差进行讨论,给出了像平面式干涉结构在单侧及双侧离焦模式下的光程差表达式,并对两者在不同波长满足奈奎斯特条件时的光程差及其非线性残差进行仿真,并通过实验验证。仿真结果表明:系统在两种工作模式下的光程差非线性残差均随像面夹角增加而增大,单侧离焦模式零级点两侧光程差不对称,且负离焦部分残差较小;双侧离焦模式零级点两侧光程差对称,但非线性残差大于前者。实验结果表明,当工作波长较短时(如紫外),单侧离焦模式负离焦部分在实际应用中可认为满足光程差线性分布关系。     

NUMERICAL INVESTIGATION OF EVOLUTION OF DISTURBANCES IN SUPERSONIC SHARP CONE BOUNDARY LAYERS

The spatial evolution of 2-D disturbances in supersonic sharp cone boundary layers was investigated by direct numerical simulation (DNS) in high order compact difference scheme. The results suggested that, although the normal velocity in the sharp cone boundary layer was not small, the evolution of amplitude and phase for small amplitude disturbances would be well in accordance with the results obtained by the linear stability theory (LST) which supposes the flow was parallel. The evolution of some finite amplitude disturbances was also investigated, and the characteristic of the evolution was shown. Shocklets were also found when the amplitude of disturbances increased over some value.     

张力结构的非线性有限元分析

张力结构中的索结构分析通常采用非线性二节点直线或二次曲线单元，但是在大跨度结构，尤其是索弯顶结构的分析中，常用的单元已不能满足精度的要求，本文提出了考虑自重作用下有初始垂度的五结点非线性空间曲线元模型，放弃了一些特殊的假定，考虑了应变表达式中高阶量的影响，推导出了适合于弹性大位移几何非线性分析的Ｌａｇｒａｎｇｄ方程及其切线刚度矩阵，编制了相应的计算程序。     

制造企业产品质量问题的信号博弈模型北大核心

基于制造企业产品质量信息不对称的特点,以制造企业和客户作为博弈方,以客户服务水平作为产品质量信号,建立信号博弈模型,分析信号博弈的三种贝叶斯均衡及其条件,得出了信息不对称情况下制造企业和客户的应对策略.     

脉冲激光作用下的量子定位实验方案的设计及分析

基于量子相干和量子空间定位的原理,设计了量子空间定位的实验方案.讨论了在脉冲激光作用下,由第二类自发参量下转换所产生的纠缠光子对的光谱特征、对应的相干函数特点以及对量子定位的影响.结果表明,随着激光脉冲宽度的增加,纠缠光子对的相干性减小,量子定位的测量准确度降低.     

Poor rich demarcation of Matthew effect on scale-free systems and its application

In a scale-free network,only a minority of nodes are connected very often,while the majority of nodes are connected rarely. However,what is the ratio of minority nodes to majority nodes resulting from the Matthew effect In this paper,based on a simple preferential random model,the poor-rich demarcation points are found to vary in a limited range,and form a poor-rich demarcation interval that approximates to k/m ∈ [3,4]. As a result,the (cumulative) degree distribution of a scale-free network can be divided into three intervals: the poor interval,the demarcation interval and the rich interval. The inequality of the degree distribution in each interval is measured. Finally,the Matthew effect is applied to the ABC analysis of project management.     

Approximating the CIECAM02 color appearance model by means of neural networks

An artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now axe widely used in calibration of digital camera, are chosen as samples to implement the forward and reverse color appearance models. When the predictive results are evaluated, for forward model, the output color appearance space is converted to the uniform color space based on CAM and is evaluated, while for reverse model, because the prediction precision is insufficient, we try to convert the color appearance space, which is the cylinder space, to the cube space similar to the red, green, and blue (RGB) space, and the results show that the precision is obviously improved.     

满足路径约束的最优路算法

满足路径约束的最优路问题已被证明是NP-hard问题。本针对源点到宿点满足两个QoS(服务质量)度量的路由问题，给出一种保证时延的最小费用路由启发式算法。这个算法的优点是计算较简单、占用内存小、时间短。算法的复杂度是多项式的，表明算法是有效的。     

恢复日立163型气相色谱仪灵敏度的方法

我单位使用的日立163型气相色谱仪是一九七八年开始使用的,一九八四年该机灵敏度明显下降,至使仪器不能正常工作。为此,对仪器、放大器的有关元器件(除组件310J 外)进行了彻底地清洗,干燥处理,都没有效果。进而检查如下项目:1.从外单位借一台放大器(同产品)装上试验,则该机工作正常,这说明仪器的放大器有问题;2.进行电路检查,反馈电阻器,输     

不等频两步激发Li蒸汽产生红外受激辐射特性研究

本文首次报道了利用不等频两步激发Li蒸汽,获得了五条红外受激辐射和串级辐射.并对受激辐射特性进行了研究.