Analysis of the microseismicity characteristics in landslide dam failure flume tests: implications for early warning and dynamics inversion

Landslides - Determining the premonitory and dynamic characteristics of landslide dam failures can provide an early warning as well the identification of the evolution of the failure process, and...     

Numerical simulation of deep-hole resistivity anomaly caused by drilling construction in Xinfengjiang geoelectric station

The Xinfengjiang reservoir in Guangdong Province, is one of the large reservoirs that have triggered earthquakes of magnitude greater than 6. Numerous earthquakes have occurred since the impoundment of the reservoir, making it one of the most active seismic zones in south China. In 2015, a set of deep-hole resistivity anomalies was observed in the Heping geoelectric station in Dongyuan county, located near the Xinfengjiang reservoir. After a field investigation, we found that a planned well drilling construction of new measuring channels was being carried out during that corresponding period of time. After careful comparison and analysis on the basis of the collected raw data, we had a reason to believe that drilling construction, rather than the inducement of the Xinfengjiang reservoir, was the main culprit for those unusual georesistivity values. So as to verify the above conjecture, we constructed a series of 3D finite element models based on the geological and hydrological information around Heping station and analyzed the drilling disturbances, respectively. Some significant conclusions were finally drawn according to the precise numerical simulation. This study gives a good example by combining numerical simulation with engineering practice as a way to understand the root cause of georesistivity anomalies in reality.     

影响海相烃源岩热解生烃过程的地质条件

热解生烃实验是研究油气生成机理与定量评价烃源岩生烃潜力的重要方法.烃源岩热解生烃模拟结果不仅与温度、压力和时间等因素有关,而且与地层孔隙水及压实成岩作用等地质因素密切相关.采用高压流体和高压釜(低压水蒸气)两种生烃热模拟方法对低成熟海相二叠统大隆组(P₂d)黑色泥岩进行了热解生烃实验模拟.对比分析两组实验结果表明地层孔隙热解实验有利于液态油的生成,不利于液态油向气态烃的转化,并极大地提高了干酪根的生油气潜力,显示了高压液态水、流体压力和孔隙空间等地质因素对烃源岩中有机质热成熟生烃反应的重要影响.这种影响可能与高压液态水的近临界特性有关,近临界特性地层水的参与改变了干酪根热力生烃反应的物理化学行为.推断在实际地质温压(100~200 ℃,30~120 MPa)条件下,烃源岩孔隙中的地层水是一种相对低温高压液态水,具有水的近临界物理化学特性,因此高压流体生烃热模拟实验与实际地层情况更为接近,能更有效地评价烃源岩生烃潜力.      

Poleward expansion of the hadley circulation in CMIP5 simulations

Observational analyses have demonstrated that the Hadley circulation has expanded poleward in recent decades. Important issues are what caused the widening of the Hadley circulation and whether the observed widening is related to anthropogenic forcing. In the present study, we use currently available simulations of the Coupled Model Intercomparison Project Phase-5 (CMIP5) to analyze changes in the width of the Hadley circulation. It is found that CMIP5 historical simulations with greenhouse gas (GHG) forcing generate a total widening of ～0.15o0.06o in latitude (10 yr)-1 for the period 1979--2005, and the widening in CMIP5 historical simulations with all forcings is ～0.17o0.06o per decade. Similar to that in CMIP3, the simulated poleward expansion in CMIP5 is much weaker than the observational reanalyses. In CMIP5 projection simulations for the 21st century, magnitudes of widening of the Hadley circulation increase with radiative forcing. For the extreme projected radiative forcing of RCP8.5, the total annual-mean widening of the Hadley circulation is ～0.27o0.04o(10 yr)-1 in the 21st century. Although CMIP5 underestimates observed poleward expansion of the Hadley circulation, the results of this study suggest that the observed trends in the width of the Hadley circulation are caused by anthropogenic forcing and that increasing GHGs play an important role in the observed poleward expansion of the Hadley circulation, in addition to other forcings emphasized in previous studies.     

往复活塞式制冷压缩机性能系数的曲面回归方程

采用非线性二乘法对国产１２．５系列往复活塞式制冷压缩机的实测性能数据进行拟合，得出描述该系列制冷压缩机性能系数与运行工况之间相关关系的曲面回归方程，为制冷系统的数值计算、动态特性模拟和优化设计提供数学模型。     

北京风沙若干问题的讨论

本文在实地调查研究的基础上提出对北京风沙一些问题的看法:1)北京风沙物质来源为本地超沙,尘的来源复杂,以外来成分最多;2)分析35午风沙资料得出这些年北京平原风沙趋于成少。     

关于地理环境的理解和运用问题

本文借助语言、逻辑知识,从“偏正结构”、“相关词义”、“派生概念”三方面,阐明了地理环境的确切含义和实际运用问题。笔者在分析、探讨地理环境问题时,提出了一些与当今辞书和重要著述相悖的定义。作者认为,长期以来,围绕地理环境及其派生概念“决定论”所开展的一切无端之争,除立场、观点和历史局限外,无不与下列问题的认识、理解不一有关:关于历史与现代决定论问题;关于决定与决定论问题;关于内外环境决定论问题。     

Ab initio prediction of 29Si-NMR chemical shifts

The ability of several ab initio models to predict experimental ²⁹Si-NMR chemical shift is examined. The shielding values of trimethylsilyl chloride (A), t-butyldimethylsilyl chloride (B) and allytrimethylsilane (C) are calculated by GIAO, CSGT and IGAIM methods, using HF/6–31G^*, B3LYP/6-31G^*, HF/6–311+G^**, B3LYP/6–311+G^** and MPW1PW91/6–311+G^** models respectively. The ²⁹Si chemical shifts calculated by GIAO method using HF/6–311+G^** model are highly in agreement with those obtained experimentally. All of the models above reproduce the trends of chemical shifts in all cases studied, suggesting that the models are of practical value.     

遥感图象的马尔柯夫随机场模型的纹理识别方法

本文讨论了马尔柯夫随机场图象模型及邻域选择方法,提出了8邻域5特征参数的马尔柯夫随机场图象模型以及一套完整而有效的特征参数的估计算法,将这些特征参数变成可视图象从而实现了视算。对8类不同纹理的标准图象进行分类试验,其识别(分类)的平均正确率达97.57％。