双石英试板和二色试板原理及灵敏度

In this article the formula for brightness of biquartz plate and dichroiscope under various conditions is derived and the most sensitive conditions for its application are established. The theoretical calculation demonstrates that for biquartz plate, the difference of brightness between the two halves reaches its maximum when rotation angle ψ of biquartz plate is equal to oblique angle A of polars from the cross position or to the apparent rotation angle of anisotroption Ar. Therefore, it is advisable to use Mace de Lepinay half-shadow wedge in which rotation angle ψ is wriable. As for dichroiscope, the difference of brightness between the two halves reaches its maximum when its vibration direction is parallel to that of the polarizer. Thus, in preparing dichroiscope,one of its vibration directions should be parallel to the polarizer.     

基于Zernike矩的多时相遥感影像匹配方法研究

针对参与变化检测影像的特点,归纳多时相影像匹配方法应满足的条件,提出了一种基于Zernike矩的匹配策略。在进行多时相影像匹配时,该方法对灰度的线性变化不敏感,而且可以匹配存在较大旋转角度的影像。试验表明,该匹配策略具有较高的匹配正确率。     

Statistical moment-based structural damage detection method in time domain

A novel structural damage detection method with a new damage index,i.e.,the statistical moment-based damage detection(SMBDD) method in the frequency domain,has been recently proposed.The aim of this study is to extend the SMBDD method in the frequency domain to the time domain for building structures subjected to non-Gaussian and non-stationary excitations.The applicability and effectiveness of the SMBDD method in the time domainis verified both numerically and experimentally.Shear buildings with various damage scenarios are first numerically investigated in the time domain taking into account the effect of measurement noise.The applicability of the proposed method in the time domain to building structures subjected to non-Gaussian and non-stationary excitations is then experimentally investigated through a series of shaking table tests,in which two three-story shear building models with four damage scenarios aretested.The identified damage locations and severities are then compared with the preset values.The comparative results are found to be satisfactory,and the SMBDD method is shown to be feasible and effective for building structures subjected to non-Gaussian and non-stationary excitations.     

内蒙古"宝音图隆起"的归属讨论

对比研究表明,内蒙古"宝音图隆起"和狼山地区的古元古代宝音图岩群与新太古代色尔腾山岩群都是由中低级变质的各种片岩、大理岩组成,一致的岩石组合和变质相暗示二者可能是等同物而不是两个岩群.以物探资料为据的构造研究也证实,"宝音图隆起"与狼山地区之间并无槽-台级的大型断裂构造分开,二者实为统一的构造整体而不是分属槽台,只因两侧被两条近于平行的NE向断裂围限,使其总构造线方向呈NE或NNE向而与色尔腾山的构造线不同.结论认为,"宝音图隆起"仍是华北陆块的一部分,不属于内蒙古-大兴安岭地槽褶皱系.     

浙江省衢州市上方镇重钙方解石矿工艺指标影响因素

重质碳酸钙的白度和色相值(Lab)是最重要的工业指标,但影响因素尚不清楚.本文通过扫描电镜、粉晶X射线衍射(XRD)和电感耦合等离子体发射光谱(ICP-OES)等分析手段,对浙江衢州上方镇的重钙方解矿石进行了研究,以期阐明重质碳酸钙白度和色相的影响因素.结果表明,矿石随研磨粒度的减小白度逐渐增加,在100～400目,白...     

条形荷载作用下梯度饱和土的动力响应分析

根据Biot波动理论,研究了条形均布荷载作用下非均匀饱和土地基的动力响应问题。利用Fourier积分变换,通过Helmholtz矢量分解原理,建立了饱和土层在动荷载作用下的回传射线矩阵法计算列式,考虑饱和土的物理力学性质沿深度方向按幂函数连续变化,采用数值Fourier逆变换获得了饱和土地基的位移、应力和孔隙压力等物理量的数值解。分析讨论了材料非均匀性对饱和土介质动力特性的影响。结果表明,非均匀饱和土的动力行为与均匀饱和土有着明显的不同,当土体的非均匀程度越高,条形荷载中点下流体压力和应力幅值越大,而位移、流体压力以及应力等物理量在水平方向的振动频率均随着土体非均匀变化程度的增强而增大。     

基于优化组合权-模糊可变集的坝基岩体质量分级

为解决坝基岩体质量指标参数不确定性问题,特别是处于相邻等级分界线附近的岩体分类问题,本文提出基于优化组合权-模糊可变集的坝基岩体质量分级模型。首先选取岩石单轴饱和抗压强度(R_c)、结构面间距(J_d)、岩石质量指标(RQD)、完整性系数(K_v)、声波纵波速度(V_P)和地应力修正系数(Q)等6个主要影响指标,将每个指标划分为5个等级;然后利用改进的序关系分析法(G1法)和最大离差法分别确定指标的主客观权重,通过矩估计法优化指标的组合权值,同时借助单因素轮换法(OAT)分析指标的敏感性;最后以金沙江旭龙水电站坝基岩体的7个标准样本作为实例,应用模糊可变集模型进行坝基岩体质量分级评判,将分级结果与云模型的判定结果进行了对比。结果表明：7个样本中,除岩体样本N3的分级结果存在差异外,其余样本的分级结果均吻合;根据野外实地勘测结果,样本N3属于Ⅱ类的概率高达80%,与本文分级结果相吻合,验证了本文方法的可靠性,也弥补了云模型关于评判坝基岩体质量的不足。此外,指标的敏感性由高到低的排序为R_c...     

断层厚度的地震效应和非对称矩张量

近几十年来,震源的矩张量表示及其反演获得了巨大成功。在震源物理的研究中,地震矩张量作为一个二阶对称张量已被广泛接受并且得到了成功的应用,但非对称矩张量则鲜有提及。本文阐述了在震源理论中非对称矩张量在物理上的合理性及其重要性,指出断层厚度的地震效应需要用非对称矩张量来表示。     

安庆4.8级地震序列的地震波谱变化研究

采用安徽区域数字地震台网记录的安庆4.8级地震序列波形资料,开展地震波谱研究,求取了零频位移谱值、应力降和地震矩等震源参数。分析了纵、横波零频谱值比和应力降随时间的变化趋势,并讨论了震源参数之间的关系。结果表明,安庆4.8级主震后,纵、横波零频位移谱值比和应力降呈现一定的变化规律,可为主震—余震序列的最大余震的预测提供一定的参考依据,同时发现震源参数与震级有一定相关。