共查询到20条相似文献，搜索用时 31 毫秒
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三维旋转式自动进样器的研制 总被引：1，自引：0，他引：1
介绍了自行研制的三维旋转式自动进样器的结构和特点，提出了三维模式、气动升降臂、旋转定位的自动进样器解决方案，并成功地用于自动进样器的研制。文章中给出了三维旋转式自动进样器的组成，气动式升降臂控制原理和系统的软件流程。 相似文献
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INTRoDUCTIoNTostudythefigureanddensityoftheearthisthebasicmissionofgravimetry.Themethodapplyingthetheoryofgravitypotentialfieldtostudytheearthfigurehassufficientlydeveloped,bycontrastwiththiscase,thesamemethodusedinthestudyoftheearthdensityisratherweak.Traditionalearthgravimetryisonintimatetermswiththetheoryoftheearthfigurebutseemstobecomeestrangedfromtheearthdensity.UndertheclassicalStokes'theoryandMolodensky'stheorythestudyontheearthfigurehasalwaysavoidedcon-sideringtheearthdensitydistr… 相似文献
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支护结构作用的箱基沉降计算新方法 总被引：1，自引：0，他引：1
现行规范在计算箱基沉降时,没有考虑支护结构的作用,使得理论计算与实际沉降之间存在误差。通过物理模拟、理论分析和数值模拟,研究箱基与支护结构结合、分离下,不同墙体材料、不同墙体厚度、不同插入深度比等工况下侧摩阻力对箱型基础沉降的影响,试验结果显示,摩擦力在箱基沉降中的作用很明显,它与墙体与土体之间的摩擦系数、墙体与土体的接触面积密切相关。在此,提出了一种计算箱基沉降的新方法,该法将箱基沉降分为3部分：箱型基础底上段回弹再压缩变形带来的地基变形、箱型基础底上段压缩变形、箱型基础的下段土体变形。以青岛中银大厦为实例,应用FLAC3D对基础沉降进行了数值分析。数值分析中按文中方法以及按前人方法的计算结果与实测数据进行了对比,结果表明文中的方法具有更好的可行性,对修订规范具有借鉴意义。 相似文献
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WINSURF二次开发在瑞雷波频散曲线正演模拟中的应用 总被引：1，自引：0，他引：1
WINSURF二次开发是物化探数据处理的一种强有力工具,以其在瑞雷波频散曲线正演模拟中的应用为例,阐述了WINSURF二次开发的基本原理、方法和技巧,并给出了源代码。正演模拟试算结果表明,该程序稳定性好、通用性强,可直接作为工具来使用,从而大大缩短了程序开发周期,避免了重复缟程和资源浪费,提高了科研和工作效率。 相似文献
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针对强震下高速铁路桥梁桩基础抗震设计中存在的问题,对桩基础的抗震性能提出了多级设防目标并给出了相应的评价指标与合理取值.借鉴FEMA440考虑桩-土三种相互作用效应的能力谱法,采用p-y、t-z及q-z曲线模拟桩周土的柔性效应,用PMM铰模拟桩身的非线性,通过Pushover分析得到桥墩的能力曲线.引入FEMA440对地基运动学效应、地基阻尼效应的地震动需求谱修正算法,对需求谱进行了修正.探讨了应用性能点轨迹法求解桩基础的延性需求及性能点的过程.以高速铁路32 m简支箱梁桥墩为研究对象,通过实例验证了该法的可行性. 相似文献
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A genetic algorithm (GA)-based neuro-fuzzy approach is used for identification of geochemical anomalies by implementing a Takagi, Sugeno and Kang (TSK) type fuzzy inference system in a 5-layered feed-forward adaptive artificial neural network. This paper investigates the effectiveness of GA-based neuro-fuzzy for separating zone dispersed mineralization (ZDM) from blind mineralization, and its application for identification of geochemical anomalies in the arid landscape of the Lut metallogenic province in eastern Iran. Other classification algorithms such as metallometry, zonality, criteria, and back-propagation artificial neural network classifiers are also used for comparison. The genetic operators are carefully designed to optimize the artificial neural network, avoiding premature convergence and permutation problems. The results show that the GA-based hybrid neuro-fuzzy model can provide accurate results in comparison with those results obtained by other techniques. Neuro-fuzzy and GA-based neuro-fuzzy techniques appear to be well-suited for routine exploration geochemistry applications. In conjunction with statistics and conventional mathematical methods, hybrid approaches can be developed and may prove a step forward in the practice of applied geochemistry. 相似文献
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Delaunay三角网嵌入约束线段算法的研究及三维可视化 总被引：3，自引：0，他引：3
研究了约束Delaunay三角网生成算法，并在无约束数据的Delaunay三角网基础上，提出了一种快速嵌入约束线段的算法，同时借助OpenGL开放式三维环境，对三角网进行光照渲染等处理，实现了地形三维可视化，更好地满足了实际应用的需要。 相似文献
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井间电磁波层析成像中的高精度时间域正演计算 总被引：1，自引：0，他引：1
为提高井间电磁波层析成像的分辨率, 正演计算中需保持较高的计算精度.本文正演计算中采用时间域伪谱(PSTD) 法模拟井间电磁波的传播.该算法在时间域有限差分(FDTD) 法的基础上采用快速傅立叶变换(FFT) 计算麦克斯韦方程中的空间导数.该算法除了具备时间域有限差分法的优点外, 在计算条件完全相同的情况下, 计算精度明显高于时间域有限差分法.时间域伪谱法的正演计算为井间电磁波高分辨率层析成像奠定了重要基础. 相似文献
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地震波旅行时计算是射线追踪方法的核心问题,其精度直接影响着路径的精度和正演模拟的准确程度。在简要分析目前最典型的几种地震波旅行时计算方法(如有限差分法、线性插值法等)局限性的基础上,提出了一种基于非线性插值的地震波旅行时计算方法,并推导了其计算公式。通过模型的对比试算,不仅验证了所提出的旅行时非线性插值算法的正确性,而且还表明本算法计算旅行时的精度,比Asakawa[5]提出的线性插值算法的精度更高。 相似文献
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利用二次场算法研究了可控源音频大地电磁法二维正演问题。采用有限单元法进行正演模拟,将矩阵压缩存储和共轭梯度解方程方法应用到正演算法中,加快了正演算法的速度,并且将地形因素考虑到正演算法中。通过不同的模型验算,检验了算法的精度。 相似文献
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This article describes a method that determines the position of a point relative to a fixed boundary. Its advantage over the other existing algorithms described below is that in most cases it is necessary that only part of the algorithm be executed to determine the position of the point. A possible inconvenience of using this algorithm is that the contour boundary has to be entered as data. For problems where the boundary often changes the algorithm is not suitable in its present form. The applications envisaged here are to cases where the position of a very large number of points have to be determined relative to one fixed polygonal boundary whose shape is known in advance, for example, blanking out of contours in automatic contouring, or selecting drill holes which lie in the particular part of a mineral deposit. 相似文献
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To improve the resolution of crosshole electromagnetic tomography, high precision of forward modeling is necessary. A pseudo-spectral time domain (PSTD) forward modeling was used to simulate electromagnetic wave propagation between two boreholes. The PSTD algorithm is based on the finite difference time domain (FDTD) method and uses the fast Fourier transform (FFT) algorithm for spatial derivatives in Maxwell's equations. Besides having the strongpoint of the FDTD method, the calculation precision of the PSTD algorithm is higher than that of the FDTD method under the same calculation condition. The forward modeling using the PSTD method will play an important role in enhancing the resolution of crosshole electromagnetic tomography. 相似文献
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An algorithm for the solution of a nonlinear problem of phase boundary movement and evolution of temperature distribution
due to the perturbation in the basal heat flux has been discussed. The reduction of the problem to a system of nonlinear ordinary
differential equations with the help of a Fourier series method leads to a stiff system. This stiffness is taken care of by
the use of a modified Euler’s method. Various cases of basal heat flow variation have been considered to show the performance
and stability of the technique for such a nonlinear system. The first case of step-wise function is taken to analyse the performance
of the technique, and the study has been extended to other general cases of linear increase, periodic variation, and box and
triangular function type variations in the heat flux. In the step-wise case the phase boundary attains a constant position
rapidly if the supplied heat flux is sufficiently large. The effect of periodicity in the heat flow is clearly depicted in
the phase boundary movement, where the phase boundary oscillates about the mean position at large times. The absence of any
constant level in the case of linear increase in heat flux is due to a very large value of heat flux. In the cases of box
car and triangular heat flux the boundary starts moving downward after the cessation of excess heat flux but does not immediately
return to its original preperturbation state, instead approaches it at large times. This technique may be applied to more
general cases of heat flow variation. 相似文献
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利用反问题新算法—时间域正演反演法研究非线性抛物型方程的逆时反问题。该方法处理反问题的主要思路是先求解相对应的正问题,获得解在特定时间网格处的近似值;然后构造一个合适的全纯映射,在象空间中获得解在时间网格对应点处的近似值;最后利用解析函数的唯一延拓性质实现反问题的逆时间反演。数值模拟例子说明了方法的有效性。 相似文献
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An automated strategy for calculation of phase diagram sections and retrieval of rock properties as a function of physical conditions 总被引：9，自引：0，他引：9
We formulate an algorithm for the calculation of stable phase relations of a system with constrained bulk composition as a function of its environmental variables. The basis of this algorithm is the approximate representation of the free energy composition surfaces of solution phases by inscribed polyhedra. This representation leads to discretization of high variance phase fields into a continuous mesh of smaller polygonal fields within which the composition and physical properties of the phases are uniquely determined. The resulting phase diagram sections are useful for understanding the phase relations of complex metamorphic systems and for applications in which it is necessary to establish the variations in rock properties such as density, seismic velocities and volatile‐content through a metamorphic cycle. The algorithm has been implemented within a computer program that is general with respect to both the choice of variables and the number of components and phases possible in a system, and is independent of the structure of the equations of state used to describe the phases of the system. 相似文献