Dynamic motion and tension of marine cables being laid during velocity change of mother vessels     

徐雪松  王盛炜  连琏 《中国海洋工程》2013,27(5):629-644

Flexible segment model （FSM） is adopted for the dynamics calculation of marine cable being laid. In FSM, the cable is divided into a number of flexible segments, and nonlinear governing equations are listed according to the moment equilibriums of the segments. Linearization iteration scheme is employed to obtain the numerical solution for the governing equations. For the cable being laid, the payout rate is calculated from the velocities of all segments. The numerical results are shown of the dynamic motion and tension of marine cables being laid during velocity change of the mother vessels.  相似文献   

Prediction of risk in submarine tunnel construction by multi-factor analysis: A collapse prediction model     

Maoxin Su  Peng Wang  Daohong Qiu  Zhiqiang Li  Teng Xia 《Marine Georesources & Geotechnology》2013,31(9):1119-1129

Abstract

Collapse is a major threat in tunnel construction. How to predict collapse risk accurately and timely is a complicated problem. In this paper, a non-linear mathematical model is applied to obtain the potential risk indices for a submarine tunnel using statistical analysis based on previous submarine tunnels, such as the Seikan tunnel and Xiang’an tunnel. Rough set theory is used to screen risk indices, determine each indicator value, and classify risk factors. Traditional weight calculation methods that are overly dependent on expert experience and other subjective factors are optimized and improved. Based on the frequency of each risk factor, the objective weight value of each risk index is determined according to weight back analysis theory. The ideal point method is used to calculate the collapse risk level. Predictions made by this new method are consistent with the actual tunnel collapse risk levels. This new method provides theoretical and technical basis for effectively predicting tunnel collapse.  相似文献   

基于Delaunay三角网矿体和采空区储量计算算法与实现     

李华  宁化展  丁希旺 《全球定位系统》2012,37(3):82-85

详细论述了矿体区域和采空区区域的Delaunay三角网生成方法,提出了一种基于矿体区域的采空区矿体储量计算方法,此方法为计算矿体已开采量和剩余储量提供了一种新途径。结合实例计算证明此算法是正确有效的。  相似文献   

基于OpenGL的规则格网地形法线计算优化研究     

韩李涛  孔巧丽  戴洪磊  牟乃夏 《测绘科学》2012,37(5):17-19

本文探讨了OpenGL的光照计算原理以及法线在光照计算中的作用,针对规则格网地形的几何结构特征提出了直接计算、方程法以及迭代法计算地形平均法线的3种方法,并分析了各自的优缺点。实验证明,迭代法由于用加法代替乘法计算,同时又避免了不必要的重复法线计算,计算效率具有明显优势。  相似文献   

辅助角法在坐标方位角反算中的应用     

郑平元  杨武年  杨容浩 《测绘与空间地理信息》2012,(7):44-45

坐标方位角反算是测量中最基本的计算之一,但传统的方位角计算方法涉及到象限问题,判断容易出错,尤其让一些初学者感到迷惘。为了使坐标方位角反算变得直观简单,提出了利用辅助角来计算坐标方位角的方法,并对其特点及应用进行了分析。  相似文献   

基于ArcGIS Server的自然保护区信息管理系统     

弥永宏  邢廷炎  周晟轩  沈赫  冯娴 《测绘与空间地理信息》2012,(7):130-133

传统的自然保护区管理方式,已经不能满足保护区管理决策部门对保护区日常管理的需求。文章运用ArcGIS Server空间分析及Asp.Net 2.0技术,设计了自然保护区系统功能结构,并在此基础上进行了系统地开发,实现了地理信息发布、生物多样性、巡护监测及巡护统计等保护区迫切需要的功能,为我国自然保护区的现代化管理进行了有益地探索。  相似文献   

高斯投影复变换的数值计算方法     

刘大海 《测绘科学技术学报》2012,(1):9-11

高斯投影复变换的数值计算简单快捷,具有重要的工程应用价值.从数值计算角度出发,使用计算机代数系统Mathcad,Matlab以及Mathematica对高斯投影复变换进行了改进:只需建立正算变换计算式而不再需要建立反算变换计算式.对于复方程,利用系统的求根函数直接求解.对于复积分,研究了积分级数分析法、椭圆积分函数法及...  相似文献   

人工神经网络在感热通量计算中的应用     

储凌  张乐坚  陈渭民 《气象科技》2012,40(3):474-480

感热通量计算方法的研究是边界层研究中最重要的内容之一。基于中日JICA计划项目中青藏高原东缘四川盆地温江站的边界层铁塔观测资料初步研究了使用人工神经网络(ANN)计算边界层感热通量的方法,并将ANN和经验公式法计算得到的感热通量分别和真值作相关和误差分析。对2009年4月和5月的两个个例研究的结果表明:ANN计算结果和真值的相关性都高于经验公式法且趋势变化和真值更加吻合,ANN计算的2009年4月的感热通量与真值的均方根误差(RMSE)稍大于经验公式法,但2009年5月的RMSE明显小于经验公式法。  相似文献   

GPS-RTK技术在高等级公路横断面测量中的应用     

李仕东 《测绘工程》2005,14(1):23-25

推出了在线路坐标系下任意中桩点的切线方位角和中桩点的坐标计算公式,求出了该中桩处横断面上任意点的坐标,提出了将GPS-RTK技术应用于路线横断面测量的基本思路和数据处理方法.  相似文献   

Adsorption of H<Subscript>2</Subscript>O,NH<Subscript>3</Subscript> and C<Subscript>6</Subscript>H<Subscript>6</Subscript> on alkali metal cations in internal surface of mordenite and in external surface of smectite: a DFT study     

Lubomir Benco  Daniel Tunega 《Physics and Chemistry of Minerals》2009,36(5):281-290

Adsorption of H₂O, NH₃ and C₆H₆ on H- and alkali metal-exchanged structures of mordenite and on corresponding cations on the smectite layer is investigated by ab initio density-functional calculations. Proton or an alkali metal cation compensates one Al/Si framework substitution and resides in the extra-framework position of zeolite or above flat smectite layer close to the Al/Si substitution. Pronounced similarities between zeolite and smectite are observed in changes of the adsorption energies and location of the external cation with changing character of the external cation. Calculated adsorption energies exhibit the following trend: E(NH₃) > E(H₂O) > E(C₆H₆). Because of looser contact with the framework, zeolitic cations are stronger adsorption centers and calculated adsorption energies of zeolites are by ~20–30% larger than cations of smectites. The highest adsorption energy is calculated for H-exchanged structures and down the group of alkali metal cations a decrease of the adsorption energy is observed. Deviations from the smooth variation of the adsorption energy are caused by: (1) formation of strong hydrogen bonds in H-exchanged structures, (2) adsorption induced migration of the external Li⁺ cation, and (3) steric hindrances of the flat C₆H₆ molecule adsorbed on the cation in the cage of zeolite.  相似文献