LSQRD及解的分辨分析

较详细地介绍了ＬＳＱＲＤ（Ｌｅａｓｔ Ｓｑｕａｒｅ ＱＲ Ｄｅｃｏｍｐｏｓｉｔｉｏｎ） 反演方法以及“检测版”分辨分析方法,并举实例检验其应用。对于大型稀疏方程组的求解,ＬＳＱＲＤ 是一种内存需求小、计算效率高和抗噪能力较强的算法。“检测版”试验表明,ＬＳＱＲＤ也可以对迭代解进行有效的可靠性估计,以指导对反演结果的利用。     

Flow Characteristics of Large-Scale Liquefaction-Slip of the Loess Strata in Shibei Tableland, Guyuan City, Induced by the 1920 Haiyuan M8 1/2 Earthquake

Based on the dynamic triaxial liquefaction test of the loess samples which are taken from Shibei tableland, Guyuan City, Ningxia, China, the characteristics of dynamic strain, dynamic stress and pore water pressure are studied under cyclic loading. Triaxial shear test is conducted immediately after the sample reaches liquefaction point. During the test, the property of the liquefied soil is analyzed through fluid mechanics method, whereby the fluidity of the liquefied soil is represented by apparent viscosity.The results show that the fluidity of liquefied loess changes from "shear thickening" to "shear thinning" as the shear force continues, and the fluidity of liquefied loess is closely related to its structure. In addition, in the process of forming a new stable state, the apparent viscosity and deviant stress change with axial strain in a similar approach. When the sample reaches its stable state, it meanwhile shows a relatively stable apparent viscosity. According to the fluid mechanics and the law of conservation of energy, the slip distance of the liquefied soil is estimated, and the results are in good agreement with the field investigation results.     

Estimation of PM_(2.5) Mass Concentration from Visibility

Aerosols in the atmosphere not only degrade visibility, but are also detrimental to human health and transportation. In order to develop a method to estimate PM_(2.5) mass concentration from the widely measured visibility, a field campaign was conducted in Southwest China in January 2019. Visibility, ambient relative humidity(RH), PM_(2.5) mass concentrations and scattering coefficients of dry particles were measured. During the campaign, two pollution episodes, i.e., from 4-9 January and from 10-16 January, were encountered. Each of the two episodes could be divided into two periods. High aerosol hygroscopicity was found during the first period, when RH was higher than 80% at most of the time, and sometimes even approached 100%. The second period experienced a relatively dry but more polluted condition and aerosol hygroscopicity was lower than that during the first period. An empirical relationship between PM_(2.5) mass concentration and visibility(ambient aerosol extinction) under different RH conditions could thus be established. Based on the empirical relationship,PM_(2.5) mass concentration could be well estimated from visibility and RH. This method will be useful for remote sensing of PM_(2.5) mass concentration.     

昆仑山口西8.1级地震后青藏高原北部地区地震活动初步研究

利用相关震例分析了昆仑山口西8．1级地震后青藏高原北部地区未来1～3年地震活动特征．结果表明,沿东昆仑构造带及邻近地区发生Ms≥7．0地震后青藏高原北部地区中强地震活动有增强的趋势,祁连山地震带和东昆仑地震带的地震活动具有交替发生的特征,未来1～3年中强地震主体活动区为大型走滑活动断裂上应力转换部位和挤压会聚构造区,如东昆仑断裂带中东段和祁连山地震带中东段和西段。     

Kinetic study of the hydrocarbon generation from Upper Paleozoic coals in Ordos Basin

When organic matter during geological processes is affected by a variety of factors such as paleotemperature, and time, complicated chemical reactions will occur, finally resulting in the generation of petroleum and natural gas. These reactions leading to…     

Potentiometric and F nuclear magnetic resonance spectroscopic study of fluoride substitution in the GaAl12 polyoxocation: implications for aluminum (hydr)oxide mineral surfaces

Fluoride replacement of oxygens in the GaO₄Al₁₂(OH)₂₄(H₂O)127+(aq) molecule [GaAl₁₂] was studied via ¹⁹F nuclear magnetic resonance (NMR) at 4 < pH < 5 and 278 K in order to elucidate similar reactions at the surfaces of clays. Peaks are identified in the ¹⁹F-NMR spectra that correspond to both terminal and bridging fluorides on the GaAl₁₂ molecule, with relative peak positions similar to those previously identified in fluoridated aluminum (hydr)oxide mineral surfaces (Nordin, J. P., Sullivan, D. J., Phillips, B. L., and Casey, W. H. [1999], “Mechanisms for fluoride-promoted dissolution of bayerite [β-Al(OH)₃(s)] and boehmite [γ-AlOOH(s)]-¹⁹F-NMR spectroscopy and aqueous surface chemistry,” Geochim. Cosmochim. Acta63, 3513-3524). Fluoride substitutes for oxygen at three different sites in the GaAl₁₂ molecule, but at dramatically different rates.The kinetics of fluoride substitution follow a rate law that includes parallel and reversible transfer of fluoride from nonbridging sites to the two bridging sites. The essential features of the rate law are as follows: (1) fluoride replaces bound water molecules (η-OH₂) within minutes at 278 K at rates that are quantitatively similar to fluoride uptake by Al(H₂O)63+(aq) to form AlF²⁺(aq) at similar conditions; (2) fluoride substitutes onto the two topologically distinct μ₂-OH sites at different rates, as was previously observed for oxygen exchange, but here, the reaction is complete in hours to days at 278 K. Most importantly, rates of fluoride substitution onto μ₂-OH sites are 10² times more rapid than the corresponding rates of oxygen exchange with bulk waters, indicating that fluoride considerably labilizes the molecule, as is also observed at the surfaces of minerals. The largest cause of this labilization is the reduced molecular charge on the GaAl₁₂ upon replacement of bound waters by fluoride, which for mineral surfaces corresponds to a reduction in surface charge density.     

基于遥感与GIS技术的城镇体系空间特征的分形分析--以绍兴市为例

在遥感技术与GIS技术的支持下,采用分形几何理论对绍兴市城镇体系空间结构特征和形态特征进行分析,探讨城镇体系的演化规律。研究表明,绍兴市城镇体系无论在空间结构上还是在空间形态上都具有分形特征。城镇分布密度由绍兴市区向周围逐渐衰减,且分布不均衡,具有向交通线集中的趋势,形成了优化的空间结构。但1984～1997年间,空间结构的演化趋向于围绕绍兴市在半径方向上均匀分布,分形特性减弱。此外,各城镇基本是以各自的中心逐渐向外扩展,空间关联性大致不变。空间形态则日趋复杂,稳定性越来越低,发展的随意性越来越大。绍兴市区这一特点更明显。     

香格里拉生态旅游资源的开发初探

1933年英国作家詹姆斯·希尔顿的小说《失去的地平线》出版 ,从此香格里拉 (Shangri-la)在人们心灵深处传播。香格里拉是迪庆藏族人民“心中的日月” ,它象征人神共有的自然和谐的美好境界 ,是天地人合一的意境。通过对香格里拉县的生态旅游资源进行梳理 ,总结了香格里拉生态旅游资源的组合特征 ,对生态旅游资源的现状进行了分析 ,并进一步探讨生态旅游产品开发过程中存在的问题 ,提出了香格里拉旅游可持续发展的对策和措施 ,以便更好地促进香格里拉旅游业的可持续发展。     

泥河湾保护区地貌特征与地质灾害

根据泥河湾保护区实地调查,黄土台地、黄土沟梁和河谷地貌是发育在“泥河湾层”及其覆地层上的主要地貌类型,其形态特征和形态测量反映了该区流水地貌的现代演化特征。伴随流水地质作用与地貌演化发生的水土流失、泥石流、崩塌和地面塌陷等地质灾害危及保护区的地层剖面。笔者认为该区域地质灾害是多种致灾因素造成的,其中的主导因素是气候、植被和人为因素,通过控制植被因素可以改变目前的地质环境状况。     

延河流域生态环境动态监测系统与应用

以遥感 (RS)、地理信息系统 (GIS)、全球定位系统 (GPS)为核心技术 ,采用 ETM/ TM卫星数据、航空机载对地观测数据 ,结合地面测试和综合调查方法 ,完成了延河流域面积 10 0 15 .797km₂的生态环境本底调查 ,建立了 1990～2 0 0 0年的生态环境动态监测系统。查明了区内主要物种和植被分布 ,土地利用 /土地覆盖现状及其动态变化 ,划分出 5个生态区 ,2 5个生态系统 ,提出了延河流域生态建设.