求解大样本核主成分分析模型的Lanczos算法

求解核主成分分析模型的技术关键是确定核矩阵端部的较大特征对。把求解大规模对称矩阵端部特征对问题的基本方法--Lanczos算法应用于核主成分分析模型的求解,设计了大样本核主成分分析模型求解的实用算法。在clapack和nu TRLan两个软件包的基础上,开发了大样本核主成分分析模型求解算法的VC++程序。用高光谱遥感图像数据进行模型求解算法的应用试验研究,证明了大样本核主成分分析模型求解算法的实用性。     

Identifying effects of local and nonlocal factors of soil water storage using cyclical correlation analysis

There are various factors governing the spatial and temporal variability of soil water storage including soil properties, topography and vegetation. Some factors act locally, whereas others act nonlocally, which means that a factor measured at one location has effect on soil water storage at another location. The objective of this study was to examine the effects of local and nonlocal controls of soil water storage in a hummocky landscape using cyclical correlation analysis. Soil water storage, soil properties and terrain indices were measured along a 128‐point transect of 576 m long from the semiarid, hummocky, prairie pothole region of North America. There are large coefficients of determination (r²) between soil water storage and sand content (r² = 0.32–0.53), organic carbon content (r² = 0.22–0.56), depth to carbonate layer (r² = 0.13–0.63), wetness index (r² = 0.25–0.45) and other variables at the measurement scale at different times, indicating strong local effects from these variables. The correlation coefficients were also calculated by physically shifting the spatial series of soil water storage with respect to that of controlling factors. The shifting improves the correlation between the spatial series, and the length of shifting indicated the difference in the response of soil water to its controlling factors. For example, the value of r² increased more than eightfold (r² = 0.47–0.64) after shifting the spatial series of soil water storage by 54 m, almost equal to the average length of existing slope, compared with the very weak correlation (r² = 0.02–0.08) at the measurement scale. This indicated the nonlocal effect from the relative elevation. The identification of nonlocal effects from factors improves the prediction of soil water storage. Copyright © 2011 John Wiley & Sons, Ltd.     

不同阻垢剂对方解石和磷酸钙表面电位的影响

采用微电泳法考察了１５种阻垢剂对方解石和磷酸钙颗粒表面电位的影响。实验结果表明,在各种药剂中,丙烯酸／２ 丙烯酰胺基 ２ 甲基丙磺酸／次磷酸调聚物对难溶盐表面电位影响最大,乙二胺四乙酸二钠盐的影响最小。乙二胺四甲叉膦酸的溶垢能力和对表面电位的影响都较强。各种药剂对两种难溶盐表面电位影响的排序差异不显著。根据配位化学和表面化学原理解释了实验结果。     

岩体破裂尺度与频率特征关系及其工程实证研究

将S变换时频分析技术引入微震信号波形分析领域,通过震源破裂尺度,研究微震信号频率特征与岩体变形破坏之间的联系。以西南地区3个水电工程作为研究对象,将大量微震监测数据作为统计样本以减小外部因素对参数计算的影响。在该基础上统计、分析岩体破裂尺度与微震信号频率之间的关系,结合大渡河猴子岩水电站地下厂房微震与多点位移计监测资料进行工程实证研究。研究结果表明,当岩体破裂尺度增大时微震信号高频成分减少,表现出低频特征;在围岩变形过程中微震信号高频成分呈现出先减少再增加的演化规律,围岩发生明显变形前微震信号出现由高频向低频转移的现象,因此,可将聚集区域内微震信号频率降低作为该区域岩体宏观变形破坏的前兆信息。研究结果可为基于微震监测的岩体工程稳定性分析及其灾害预测预报提供参考。     

宜良地热田水化学特征分析与研究

水化学特征不仅应用于分析地下水水质的时空变化规律,而且还提供地下水水动力环境信息。水化学分析方法已成为对探索地热田成因、地下水补给来源等常用的研究方法。基于近些年的研究资料,综合分析热储层结构特征和水化学特征,认为宜良地热田为层状热储型中低温地热田,其热储层为震旦系灯影组。研究热储层流体的化学分布特征以及热流体的化学成分与温度的关系等,用化学温标核算了热储层温度,认为K-Mg温标更适用于中低温地热田热储温度的估算。地热水水化学特征等基本地质特征可作为地热田规划和开发的理论基础。     

斜坡地基上高填方路堤极限承载力研究

结合山区高速公路建设的实践,采用大型室内模型试验,找出了荷载作用下斜坡地基上高填方路堤滑动破坏面出现的位置及形态,并确定了其极限承载力的大小。在通用条分法的理论基础上运用Visual Basic编程语言编制了斜坡地基上填方路堤极限承载力计算程序,并应用于该试验模型的计算分析,计算与试验结果的对比分析表明,利用极限平衡通用条分法不仅简单可行,且具有较高的计算精度。     

低温高压微地质体中微米纳米级矿物相研究——以大冶葡萄石中绿纤石和多硅白云母为例

低温高压地质体因与地壳碰撞、俯冲等构造活动密切相关,长期以来一直是国内外地学界关注的研究对象。但由于受研究手段、分辨能力所限,对于呈微米纳米级微粒形式存在于低温高压微地质体（即矿物）中的成分、物相及其成因等问题的研究,至今仍是地学研究中的薄弱环节。随...     

地学信息图谱时空维的诠释与应用

地学信息图谱所研究的地理空间规律和地理过程均具有一定的区域相似性, 故其在空间和时间上具有一定的区域特征,因此对地学信息图谱的研究均有空间和时间尺度方面的范畴。尺度是研究客体或过程的空间维和时间维。根据研究性质、研究对象的空间规模等方面的不同,地学信息图谱的空间尺度可分为大尺度、中尺度和小尺度;按研究的时间尺度不同,地学信息图谱的时间尺度可分为长时间尺度、中等尺度和短时间尺度。地学信息图谱的时空维是指地学信息图谱数据源的时空维或地学信息图谱可以表达的时空维,不同的时空维表达不同的特征和内容。     

A dynamic network model for two‐phase immiscible flow

A dynamic pore‐scale network model is formulated for two‐phase immiscible flow. Interfaces are tracked through the pore throats using a modified Poiseuille equation, whereas special displacement rules are used at the pore bodies. The model allows interfaces to move over several pore‐lengths within a time step. Initial computational results are presented for a drainage experiment to demonstrate some of the features of the model. This revised version was published online in July 2006 with corrections to the Cover Date.     

Weathering: Toward a Fractal Quantifying

Weathering occurs over a wide range of scales. To link features through these scales is a major challenge for interdisciplinary weathering studies. Fractal approach seems to be specially useful for this purpose. We introduce a multistep fractal weathering assessment scheme devoted to extract fractal weathering classifiers from texture analysis of the mineral's image. Our scheme enables to quantitatively estimate the global and local information about the geometry of the weathering pattern. This information is basic to develop geometrical indices of weathering, which can significantly enrich the common qualitative and semiquantitative weathering assessment schemes. To justify the fractal approach, a strong statistical self-similarity has been documented for both the weathering and fresh features of two common silica minerals: quartz and biogenic A-opal (phytolith) over four orders of length scales. The procedure is fast, drastically reduces thresholding bias, promises to be universal, it is valid for genetically different minerals and rock types, scale independent, and specially useful for monitoring the changes in the mineral's roughness during the alteration. Two of the proposed classifiers seem to be potentially useful for direct application in the field and be used by nonspecialist.