离子刻蚀全息光栅的研究     

沈邦兴  李开新  张谊萍 《武汉大学学报(信息科学版)》1987,(1)

利用国产的光刻胶和国产离子刻蚀机在蒸镀的铝基衬底上进行刻蚀全息光栅,在国内是一项较新的技术。本文介绍和论述了该试验工作的工艺过程、参数计算和测试方法,得出了试验结果和参数计算值基本吻合的结论,并指出了进一步改善质量的方向。  相似文献   

三山岛金矿矿柱的稳定分析     

凌荣华  丁恩保 《工程地质学报》1995,3(2):42-46

本文基于三山岛金矿工程地质条件，针对设计所提出的采场和矿柱的尺寸，提出了分析矿柱稳定性的一种新的方法，并应用该方法分析了矿柱的稳定性；同时，提出了提高矿柱承载能力的一种有效途径。另外，还详细讨论了矿柱顶点的深度与长度之间存在的关系。  相似文献   

钢梁阻尼器的最佳延性率及其控制     

陆顺永 《地震工程与工程振动》1995,15(4):85-92

基于双线性和三线性的力－位移滞回线假设，导出了钢梁阻尼器隔震系统等效阻尼比与阻尼器延性率的关系；为了获得大阻尼比隔震系统，以尽量减小隔震系统的地震反应，求得了使系统阻尼比为最大的阻尼器相应延性率（即最佳延性率）所需满足的条件；给出了在给定地震地面运动输入条件下，使系统阻尼器变形位移达到最佳延性率的阻尼器初始刚度和屈服位移的确定方法。  相似文献   

滑坡钢筋砼格构防治"倒梁法"内力计算研究   总被引：2，自引：0，他引：2  

殷跃平 《水文地质工程地质》2005,32(6):52-56

格构锚固技术能有效地控制滑坡深部和浅表破坏,提高锚固体系的整体刚度。目前在格构 锚杆体系的设计中,大多采用经验设计钢筋砼格构,常导致配筋不合理,不仅造成浪费,而且可能埋下工程隐患。本文采用“倒梁法”对格构梁的内力计算方法进行研究,对滑坡防护钢筋格构进行如下简化:(1)锚杆对格构梁的作用以垂向力为主,轴向力可以忽略不计。(2)纵向格构梁的刚度大于横向格构梁的刚度,因而横向格构梁的内力计算可以简化,钢筋砼格构可以作为在锚杆施力下的超静定连续梁。结合三峡工程库区巫山新城秀峰寺滑坡格构防护工程设计,通过“三弯矩方程”进行了格构梁内力实例计算,为格构梁的合理设计提供了依据。  相似文献   

Gaussian beams in inhomogeneous media: A review     

Yu. A. Kravtsov  P. Berczynski 《Studia Geophysica et Geodaetica》2007,51(1):1-36

The paper outlines the most important results of the paraxial complex geometrical optics (CGO) in respect to Gaussian beams diffraction in the smooth inhomogeneous media and discusses interrelations between CGO and other asymptotic methods, which reduce the problem of Gaussian beam diffraction to the solution of ordinary differential equations, namely: (i) Babich’s method, which deals with the abridged parabolic equation and describes diffraction of the Gaussian beams; (ii) complex form of the dynamic ray tracing method, which generalizes paraxial ray approximation on Gaussian beams and (iii) paraxial WKB approximation by Pereverzev, which gives the results, quite close to those of Babich’s method. For Gaussian beams all the methods under consideration lead to the similar ordinary differential equations, which are complex-valued nonlinear Riccati equation and related system of complex-valued linear equations of paraxial ray approximation. It is pointed out that Babich’s method provides diffraction substantiation both for the paraxial CGO and for complex-valued dynamic ray tracing method. It is emphasized also that the latter two methods are conceptually equivalent to each other, operate with the equivalent equations and in fact are twins, though they differ by names. The paper illustrates abilities of the paraxial CGO method by two available analytical solutions: Gaussian beam diffraction in the homogeneous and in the lens-like media, and by the numerical example: Gaussian beam reflection from a plane-layered medium.  相似文献   

Rank-Defect Adjustment Model for Survey-Line Systematic Errors in Marine Survey Net     

LIU  Yanchun  LI  Mingsan 《地球空间信息科学学报》2002,5(4):14-20

In this paper,the structure of systematic and random errors in marine survey net are discussed in detail and the adjustment method for observations of marine survey net is studied,in which the rank-defect haracteristic is discovered first up to now.On the basis of the survey-line systematic error model,the formulae of the rank-defect adjustment model are deduced according to modern adjustment theory.An examle of calculations with really observed data is carried out to demonstrate the efficiency of this adjustment model.Moreover,it is proved that the semi-systematic error correction method used at present in marine gravimetry in China is a special case of the adjustment model presented in this paper.  相似文献   

Delaunay三角网内插特征点算法研究   总被引：8，自引：2，他引：8  

刘少华  程朋根  陈红华  吕开云 《华东地质学院学报》2002,25(3):254-257

在Delaunay三角剖分网的基础上，对内插特征点算法进行了研究，提出了一种快速内插点算法。根据本算法的特点，提出了一种快速确定点所在的三角形的方法。  相似文献   

堆载地基与邻近桩基的相互作用分析   总被引：9，自引：0，他引：9  

杨敏  朱碧堂 《水文地质工程地质》2002,29(3):1-5,9

本文在分析堆载条件下邻近桩基与土体的相互作用时，提出了改进弹性地基梁模型，采和最小势能原理推导了改进弹性地基梁的有限杆系法平衡方程，并编制了相应的分析程序EFBMPP，对影响桩基变位和弯矩的影响因素进行了计算分析。  相似文献   

A review of algebraic constraints in terrestrial reference frame datum definition     

P. Sillard  C. Boucher 《Journal of Geodesy》2001,75(2-3):63-73

 Station coordinates are combined with velocities estimated by space geodesy techniques to produce the International Terrestrial Reference System. The input is sets of coordinates and velocities calculated by International Earth Rotation Service analysis centers using space geodesy techniques. The working reference system of individual analysis centers is generally conventionally defined. However, the implications of such processing can have an effect on the resulting combined set. The problem of datum definition as a function of coordinate combinations is reviewed. In particular, the problem of minimum constraints is clearly emphasized and the reference system effect is defined. The goal is to build a process that could be used generally to remove uncertainties in the underlying coordinate system without disturbing the underlying information with additional unnecessary information. Received: 25 January 1999 / Accepted: 20 September 2000  相似文献   

利用卫星资料试作青藏高原地表净辐射场的气候反演   总被引：3，自引：1，他引：3  

翁笃鸣  高歌 《气象科学》2001,21(2):162-168

利用 ERBE和 ISCCP卫星辐射及总云量资料 ,结合已提出的地表短波吸收辐射 ,大气逆辐射以及地表长波辐射的气候反演方法 ,计算出 2 5°～ 4 0°N,75°～ 95°E间 2 .5°× 2 .5°经纬度网络点及高原 63个站点的各月平均地表净辐射 ,绘制出其在高原的分布图 ,揭示其时空分布特征。  相似文献