Reduction of hydroelastic responses of a very-long floating structure by a floating oscillating-water-column breakwater system

The hydroelastic responses of a very-long floating structure (VLFS) placed behind a reverse T-shape freely floating breakwater with a built-in oscillating water column (OWC) chamber are analyzed in two dimensions. The Bernoulli–Euler beam equation is coupled with the equations of rigid and elastic motions of the breakwater and the VLFS. The interaction of waves between the floating rigid breakwater and the elastic VLFS is formulated in a consistent manner. It has been shown numerically that the structural deflections of the VLFS can be reduced significantly by a suitably designed reverse T-shape floating breakwater.     

三种类型烃-烃不混溶包裹体组合的特征和热力学条件的计算

在自然界广泛分布着烃-烃不混溶体系中捕获的流体包裹体,由于这些包裹体具有复杂的组成和相态,因此不混溶包裹体组合的判别和热力学参数的计算常常难以进行。根据烃-烃不混溶体系中两个端员组分流体包裹体室温下的相态特征和在温度-压力平面图上等容线交点显示的位置,划分成三种类型流体包裹体组合,本介绍了三种类型流体包裹体组合特征,叙述了不混溶烃-烃包裹体组合的测定和判别方法,并且阐述均一化包裹体相态方程和气-液平衡常数原理和方法与此同时列举了自然界简单的三种类型不混溶烃-烃包裹体组合的测定、判别和计算的几个实例,利用相态方程和气-液平衡常数,不但精确地计算出包裹体均一压力,并且精确地计算出流体密度和体积等热力学参数。最后,利用均一成气相和液相的两种包裹体在 p-T 平面图上等容线交点同样计算出流体包裹体组合的捕获温度和压力。     

基于边界积分方程的"准三极"法电阻率层析成像

基于边界积分方程,提出了依据二极采样数据、但利用电位差的某种线性组合的"准三极"电阻率层析成像方法.研究表明,该方法不仅较好地解决了对高阻异常体的成像问题,而且使低阻异常体的成像质量获得了明显改善和提高,因此增强了电阻率层析成像技术的实用性.     

UBV光电测光系统的转换方程和精度比较

根据对鬼星团中Ｊｏｈｎｓｏｎ测光标准星的观测，我们研究了北京天文台６０ｃｍ望远镜直流光电光度计ＵＢＶ测光系统的转换方程．应用该方程推算了对三颗变星观测得到的ＵＢＶ星等，讨论了所得光变曲线的精度，并与较差方法所得结果进行了比较     

非线性波动理论在地震勘探中的应用综述

从非线性科学入手,详细地分析了非线性波动场产生的物理机制及国内科学者对非线性波动理论的研究现状,对非线性波动问题的求解技术进行详细概述,并分析了各种算法的特点,最后对非线性波动现场今研究的一些物理现象进行了综合分析,并探讨了非线性波动理论在地震勘探中的应用前景。     

On derivation of EIH (Einstein–Infeld–Hoffman) equations of motion from the linearized metric of general relativity theory

The half-century old idea of Infeld to use the variational principle of the general relativity field equations is reminded to show that the commonly employed EIH (Einstein–Infeld–Hoffman) equations of motion may be derived from the linearized (weak-field) metric alone. Based on it, the linearized metric might be sufficient for post-Newtonian celestial mechanics and astrometry enabling one to derive the post-Newtonian equations of motion and rotation of celestial bodies as well as the post-Newtonian equations of light propagation within the general relativity framework.     

Transient electromagnetic field in magneto-viscous medium

When using Transient Geo-Electromagnetics (TEM) unusually slow decaying transients are sometimes observed in the absence of well-conductive objects. Many researchers explain this phenomenon by presence of material with magneto-viscous or superparamagnetic (SPM) properties. The analysis of electromagnetic (EM) field equations in conductive SPM medium is suggested in the present paper. It is shown that in a simplest case of small size single-domain magnetic particles with relative higher potential barrier energy, the SPM-medium is characterized by a very slow decaying exponential transient magnetic field, the level of which is much more as compared to that of due to non-magnetic medium of the same conductivity. This situation is traced up to the late transient time like 0.1 s and more. SPM and Induction fields are in the near zone additive. They depend in a different way on the superparamagnetic and electric properties of the SPM-medium. They also depend in different ways on the transient time and on the size of the transmitter–receiver configuration. These characteristics make it possible to recognize the presence of SPM-effect and to separate these fields.     

Hybrid three-dimensional finite-difference and finite-element analysis of seismic wave induced fluid–structure interaction of a vertical cylinder

The two-dimensional finite-difference scheme has been extended to three dimensions to solve nonlinear hydrodynamic pressures and structural responses of a deformable, vertical and circular surface-piercing offshore cylinder during earthquakes. A complete three-dimensional analysis has been made with both the three-dimensional equations of motion and the simultaneous action of three components of ground acceleration included in the analysis. Not only the magnitude but also the direction of the acting ground motion can be varied with time. The dynamic response of a cylinder is approximated by the displacements in the fundamental modes of vibration. A comparison of the dynamic displacement of the cylinder with and without surrounding sea water has been made. The flexibility of the offshore cylinder can significantly increase the hydrodynamic pressures acting on cylinder faces, that is, the fluid-structure interaction is necessary in offshore cylinder analysis. Although the hydrodynamic pressure induced by the vertical ground acceleration of the El Centro 1979 earthquake is significant, the calculated structural dynamic response of a cylinder is very small and the corresponding resultant hydrodynamic force is almost nil. The hydrodynamic force induced by two-horizontal ground acceleration is about the same as that by three simultaneous components of ground acceleration. For a solid and stubbier circular cylinder, the vertical component of ground acceleration may be neglected.     

用逐次面积矩法解简单超静定梁

本文用逐次面积矩法解超静定梁。这是一种简单的方法,只要画出多余未知力的单位弯矩图,计算出它的面积,一次矩,二次矩,三次矩,然后按照梁上的载荷建立变形协调方程,多余未知力即可算出。     

一种GPS网三维平差的数学模型

本文采用带约束条件的间接平差法，给出了取空间直角坐标（Ｘ，Ｙ，Ｚ）为未知参数的ＧＰＳ网三维平差的数学模型。这种模型既便于将ＧＰＳ网的平面部分与高程部分分别处理，又便于对一些理论和实际问题进行分析和研究，此外，文中还对求解方法作了必要的说明，并且简要地介绍了按这各模型研制的软件系统。