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从目标函数的线性化出发,采用奇异值分解法求广义逆矩阵并适当加阻尼,用迭代法直接解超定方程实现改进广义逆矩阵反演。进一步从理论与实际结合上阐明改进广义逆矩阵反演法的灵活、稳定,它涵盖了多种反演方法的优点,又具有自身特点,在实际应中适应性强,并能提供一些辅助信息,可更好地评价解释结果。 相似文献
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鄂尔多斯盆地西缘发育南北向展布的逆冲推覆构造带,通过求其地层的缩短量和正确估计应变的分布,可以定量地揭示岩层的变形特征,从而对逆冲推覆构造形成的动力学机制做出客观的判断。由于小尺度褶皱和断层的发育,采用传统的平衡地质剖面方法计算其缩短量往往存在较大的误差,因此,采用非线性的方法--分形几何学求取逆冲推覆构造的缩短量,将剖面中某一地层界线作为二维平面中的一条复杂曲线,求其分维数D,进而计算构造变形的总缩短量。以鄂尔多斯盆地西缘北段桌子山地区AB地质剖面为例进行了应用研究。计算结果表明,桌子山AB地质剖面的缩短量为8 km,应变为22.2%,其中由小尺度褶皱和断层引起的的缩短量为1 km。 相似文献
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在数学地质和地质测绘的计算工作中,常常遇到解算高阶方程组的问题。以往只能应用中小型计算机来解题。目前,我国引进为数较多的PC—1500和PC—1501袖珍计算机。应用这类计算机,据笔者初步探索,在巧妙安排内存时,可解算高达70阶(具有16K模块时)或44阶(具有8K模块时)的方程组。内客包括正规方程组的组成、求逆阵、求待定参数。现提供一份程序供实算使用。 相似文献
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在建立地下水流模型的过程中,模型验证一直是较为复杂的步骤之一,具体难点包括寻优方法的选用,为保持总体平衡所引起的参数峰值异常以及总体寻优需要大量的计算机时等问题。本文运用区域分解法中D-N交替法的基本思想,在计算目标函数值时,将整体求解水文地质模型的过程分解为计算各参数分区内的子模型的过程,并在双核计算机上实现了并行计算。理想算例的计算结果证明了该方法用于水文地质逆问题求解的可行性,它不仅减少了求解过程中所需要的计算机时,而且提高了参数的拟合度。最后将这种方法应用到山东鹏山水源地的水文地质参数求解问题中,由结果可以看出,运用该方法反求水文地质参数是可行的,具有很好的应用前景。 相似文献
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修正γ辐射取样结果用的等效射气系数值,野外通常采用积累平板法测定。该方法用于矿石结构较紧密的地段是有效的,对于矿石破碎严重,充填物无法与矿体表面紧密贴在一起的地段,该法误差较大。为此,我们在7903地区10个矿体上,用γ辐射取样和刻槽取样结果进行对比,用逆推法求等效射气系数值,其结果令人满意,现简介如下。 相似文献
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曾绍炳 《华东地质学院学报》2007,30(1):51-54
在测量平差计算中,相当多的计算工作是矩阵转置、求逆、相乘等,人工解算容易出错,且现有各种平差软件一般均为过程隐含式的,不利于测量初学者掌握测量平差原理。探讨利用电子表格软件(Excel2003)的内置函数中的矩阵运算功能处理测量平差计算的方法,并以水准网条件平差的解算为例,介绍其使用方法及使用技巧,得到一些有益的结论。 相似文献
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地下水模型的Neumann展开Monte-Carlo随机有限元法 总被引:1,自引:0,他引:1
讨论了求解地下水模型(水流模型和水质模型)的Neumann展开Monte-Carlo随机有限元法。从基本的随机变量入手,避免了过程中随机变量的增多问题,给出结点水头(浓度)的均值、方差和水头在某区间的概率计算方法;改进了矩阵求逆的效率,对输入随机变量较多、随机变量变异较大的非稳定地下水问题特别有效。同时选取二维承压地下水水流问题(有解析解)作为例子,进行了随机数值模拟实验。 相似文献
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G. V. Gibbs D. F. Cox K. M. Rosso A. Kirfel T. Lippmann P. Blaha K. Schwarz 《Physics and Chemistry of Minerals》2005,32(2):114-125
Generalized X-ray scattering factor model experimental electron density distributions and bond critical point, bcp, properties generated in recent studies for the earth materials stishovite, forsterite, fayalite and cuprite with high energy single crystal synchrotron X-ray diffraction data and those generated with high resolution diffraction data for coesite and senarmonite were found to be adequate and in relatively good agreement, ~5% on average, with those calculated with quantum chemical methods with relatively robust basis sets. High resolution low energy single crystal diffraction data, recorded for the molecular sieve AlPO4-15, were also found to yield model electron density distribution values at the bcp points for the AlO and PO bonded interactions that are in relatively good to moderately good agreement with the theoretical values, but the Laplacian values of the distribution at the points for the two bonded interactions were found to be in relatively poor agreement. In several cases, experimental bcp properties, generated with conventional low energy X-ray diffraction data for several rock forming minerals, were found overall to be in poorer agreement with the theoretical properties. The overall agreement between theoretical bcp properties generated with computational quantum methods and experimental properties generated with synchrotron high energy radiation not only provides a basis for using computational strategies for studying and modeling structures and their electron density distributions, but it also provides a basis for improving our understanding of the crystal chemistry and bonded interactions for earth materials. Theoretical bond critical point properties generated with computational quantum methods are believed to rival the accuracy of those determined experimentally. As such the calculations provide a powerful and efficient method for evaluating electron density distributions and the bonded interactions for a wide range of earth materials.Dedicated to Professor Robert F. Stewart of Carnegie Mellon University on his retirement for his brilliant and original work modeling electron density distributions. 相似文献
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站队结合流量测次精简分析方法的研究 总被引:1,自引:1,他引:1
Hydrological Service of Hunan Provinee 《水文》1995,(2):11-18
为适应站队结合的需要,必须对流量测次作精简分析。本文以湖南省株洲站队结构区为研究实例,在测站特性分析的基础上,根据水力因素和环境因素对水位流量关系的影响,将区内测站按水位关系稳定,较稳定、不稳定进行分类。 相似文献
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Pyrolysis kinetics are determined for a series of asphaltene samples associated with different types of kerogens. The activation energy distributions obtained for asphaltenes related to type I kerogens cover a wide range, with significant hydrocarbon generation with activation energies above 350 kJ/mol. The ranges of activation energy distributions are relatively narrow for asphaltenes associated with type II and III kerogens, with little hydrocarbons generated with activation energies above 350 kJ/mol. If the type of associated kerogen can be reasonably constrained, the pyrolysis kinetics of the asphaltenes is potentially a very useful tool for assessing the maturity levels of reservoired oils. The results of pyrolysis kinetics indicate that there is still significant potential for asphaltenes to regenerate hydrocarbons. 相似文献
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泡塑富集-硫代米蚩酮萃取微珠比色法在野外测金的应用 总被引:5,自引:0,他引:5
在野外交通不便和无电力条件下,应用泡塑富集-硫代米蚩酮微珠萃取比色法,实现了5~1200ng/g金的测定,结果与室内化学光谱法比较,无明金样品的相对误差可控制在60%以内,含明金样品的相对误差基本在100%~500%,可以满足化探找金及异常查证的要求。方法能有效地指导化探找金工作。 相似文献
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S. I. Grachev 《Astronomy Reports》2001,45(12):960-966
The paper formulates the standard theory for the transport of polarized radiation in the presence of resonance scattering in an atmosphere with a weak magnetic field, so that the Zeeman splitting is small compared to the Doppler line width. For an atmosphere with conservative scattering, this reduces to the Milne problem, which consists of computing a polarized radiation field in a medium with sources lying in infinitely deep layers. In the approximation of complete frequency redistribution, the problem reduces to solving a Wiener-Hopf integral equation for a (6×6)-matrix source function. Asymptotic and numerical solutions for the standard problem are obtained, including solutions for the Milne problem, for the case of a Doppler absorption profile. The line polarization profiles for the emergent flux at various angular distances from the disk center are derived, and the dependence of the limiting degree of polarization (at the line center at the disk edge) on the direction of the magnetic field is computed. For nearly conservative scattering with photon destruction probability ε?1, the limiting degree of polarization varies with ε in accordance with a simple empirical law similar to that found earlier for a medium with zero magnetic field. 相似文献
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基于流溪河模型构建了不同空间分辨率的新丰江水库入库洪水预报模型,采用粒子群算法优选模型参数进行洪水模拟,对比实测资料验证了模型性能。结果表明,建立的新丰江水库入库洪水预报流溪河模型模拟效果优良,符合新丰江水库入库洪水预报的精度要求,可用于新丰江水库入库洪水预报:90 m空间分辨率的模型模拟效果最好,200 m空间分辨率的模型也具有良好的模拟性能,500 m空间分辨率的模型模拟性能有明显降低。模型计算工作量随分辨率的提高呈指数增加,90 m空间分辨率的参数优选时间是200 m空间分辨率参数优选时间的7.04倍,而200 m空间分辨率的参数优选时间是500 m空间分辨率参数优选时间的3.53倍。 相似文献
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针对浅埋暗挖洞桩法理论分析落后于工程实践的实际情况,依据地下结构设计计算理论的地层--结构法,以有限单元法作为分析手段,建立三维计算模型,系统开展了浅埋暗挖洞桩法施工过程的数值模拟,以及参数变化对洞周围岩稳定性和位移场的影响分析。结果表明:浅埋暗挖洞桩法用于大断面洞室或超浅埋洞室暗挖施工时,洞周围岩稳定性良好,并可有效控制地表沉降。洞室跨度为14 m左右时控制地表沉降的效果最好;在不同埋深条件下控制地表沉降的效果基本相同;洞室高度的影响则不明显。研究的结论对今后浅埋大断面单跨洞室暗挖施工方案比选和采用浅埋暗挖洞桩法施工具有指导 作用。 相似文献
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A routine method for the direct determination of Au and associated trace metals in sulfides has been developed for use with a low-flux nuclear reactor (SLOWPOKE II Reactor Facility, University of Toronto). Small samples (100–200 mg) are analysed simultaneously for Au, Ag, As, Sb, Mo, Co, Se, Cd, Fe, and Zn. Sulfides containing finely divided gold can be analysed with a high degree of precision and yield results which agree closely with commercial fire assay-atomic absorption analyses for Au. Favourable comparisons with other analytical techniques (flameless atomic absorption and emission spectrometry) are also indicated for Ag, As, and Sb. Neutron activation has the advantage of providing precise and accurate results for these elements without chemical separation or preconcentration. Analyses of 10 sulfide-bearing reference materials from CANMET, Ottawa are compared with published best values for selected trace metals including Au. 相似文献