角钢插入式基础抗拔破坏机理研究

通过对角钢插入式基础抗拔试验,分析了角钢与混凝土之间的黏结性能及应力分布特点,探讨了角钢插入式基础抗拔破坏的影响因素,重点研究了插入式基础角钢与混凝土之间的摩擦系数的变化规律,给出了一个比较符合实际且又方便设计的平均摩擦系数。     

Seismotectonic database of Turkey

Turkey is located in one of the most seismically active regions in the world. Characterizing seismic source zones in this region requires evaluation and integration of geological, geophysical, seismological and geodetical data. This first seismotectonic database for Turkey presented herein was prepared, under the framework of the National Earthquake Strategy and Action Plan—2023. The geographic information system (GIS)-based database includes maps of active faults, catalogues of instrumental and historical earthquakes, moment tensor solutions and data on crustal thickness. On the basis of these data, 18 major seismotectonic zones were delineated for Turkey and the surrounding region. The compilation and storage of the seismotectonic data sets in a digital GIS will allow analyses and systematic updates as new data accrete over time.     

Distribution and release mechanism of heavy metals in sediments of Yelang Lake by DGT

Stochastic Environmental Research and Risk Assessment - The deposition and release of heavy metals in sediments often lead to their diffusion in lakes, especially for dispersed elements such as...     

基于Google Earth的果化示范区石漠化评估

充分挖掘Google Earth(GE)提供的免费数据,可以克服数据缺乏区域无图可用的困难。以典型峰丛洼地果化示范区为例,基于GE和GIS技术,建立了果化示范区数字高程模型。利用植被覆盖度和坡度两个指标对研究区域2003年石漠化进行定量评估。结果表明,2003年示范区石漠化面积为5.63km2,比重高达64.7%;研究区域以轻度石漠化为主,轻度石漠化面积为3.92km2。      

S型花岗岩中锆石U-Pb同位素体系的多阶段演化及其年代学意义─—以桂北三防岩体为例

S型花岗岩中含有残留锆石并经历过后期Pb丢失事件是一个较普遍的现象,这使得其钻石U－Pb体系呈现出复杂的多阶段演化特征。虽然离子探针对各种复杂锆石U－Pb体系定年最为有效,但因其昂贵的成本使其应用受到限制,目前较为常用的仍是常规化学－质谱分析方法。在现有实验室Pb本底水平上恰当地选择单颗或多颗粒锆石进行分析,是获得高质量U－Pb年龄数据的关键。桂北三防岩体含有残留锆石并经历过后期Pb丢失事件,使其锆石U－Pb体系具有三阶段演化的特征。离子探讨和多颗粒锆石化学－质谱两种分析方法得出了一致的207Pb／206Pb年龄为820±9Ma,代表了岩体的形成年龄。而过去用常规微量锆石化学－质谱法得到的年龄（899Ma）实际上是一个无地质意义的“上交点年龄”。     

咸阳机场一次阵风锋的探测和自动识别

利用西安多普勒雷达观测资料、NCEP再分析资料和自动气象站资料,对2016年6月4日发生在咸阳机场附近的一次阵风锋天气展开研究。这次过程是由蒙古低涡主导,低涡后部的冷空气南下触发对流引起的,阵风锋过境时咸阳机场产生了2.2mm降水和19.7m·s^(-1)的大风天气,多架次航班受到影响。从雷达回波的分析发现,这次阵风锋的特征表现为,生命史2h左右,回波强度5~25dBz,长度约70km,平均移速达49.7km·h^(-1),伴有明显的窄带回波和辐合线。对雷达基数据进行质量控制后,设计了自动识别软件,在强度场上利用双向梯度算法,以及速度场上使用Shear参量算法,根据窄带回波和辐合线的空间一致性,对该阵风锋的位置和强度进行识别。最后利用临界成功指数对这个软件进行评估,本次阵风锋的识别率达到83.33%,表明该软件能够识别阵风锋,可在业务中使用。     

固体降水自动化观测试验

介绍了2006年1～9月在吉林长春站、黑龙江通河站、新疆大西沟站进行的固体降水自动化观测仪器对比试验,共有6个厂家3种类型21套仪器参加了为期9个月的对比试验,本次对比采用WMO（1985）推荐的双栅式对比用标准器（DFIR）作为试验对比标准器。通过对比试验考察了融雪型雨雪量计、称重式降水计、激光式降水计测量不同形态降水的性能特点,为固体降水自动化观测仪器选型提供依据,推进固体降水业务化工作。     

华北地台五台、中条、集宁区前寒武系铀矿化与找矿方向的讨论

本文首先概述了寒武纪地质发展史。太古代早期只出现小面积古陆核,岩石含铀量低,硅铝壳演化晚。早元古代稳定性差,盖层形成晚。因此,对寻找澳北型铀矿床不利。但中生代地台活化对寻找花岗岩型铀矿床创造了条件。铀矿花分布在古陆核两侧,围绕古陆核划分三个分带:内带——太古代古陆核为钍矿化区,多为花岗伟晶岩型;中带——古陆核边缘凹陷为铀钍混合区,铀多为变质热液型,碱交代型,与硅化带、破碎带、混合岩化及岩体接触带有关;外带——中生代花岗岩分布区为铀矿化区。中生代化岗岩是本区主要成矿岩体。集宁区凤凰山岩体,铀矿化分布于岩体边缘顶盖相,属硅质脉型。五台区盘道岩体,铀矿化主要产于岩体外接触带,有萤石型与玉髓型两种。上述共同特点:富硅、富钾、铝过饱和岩石,成矿类型与岩石化学成分都可与华南花岗岩对比。铀矿找矿方向:主要在古陆核外带中生代花岗岩呈北东向展布区,特别是围绕花岗岩内外接触带,寻找硅质脉型是最有远景的。其次是在中条区西侧山前大断裂复背斜核部,特别是断裂拐弯处和混合岩化强烈地段,寻找变质热液型、碱交代型是比较有利的。     

石榴石单矿物阶段淋滤Pb-Pb同位素定年技术

利用阶段酸淋滤Pb-Pb同位素定年技术，获得了豫西蛇尾雪花沟黑云母石榴夕线石片岩中石榴石中单矿物427±63Ma的Pb-Pb等时线年龄，为揭示豫西东秦岭核部杂岩局部叠加加里东接触变质作用，提供了直接的同位素年龄证据。     

An exploratory spatial data analysis of low birth weight prevalence in Georgia

Low birth weight (LBW), defined as a live birth weighing less than 2500 g, is a significant public health problem in the United States, but the complex nature of the etiology of this problem is not fully understood. Moreover, significant disparities in LBW prevalence are well documented among certain populations, particularly in minority and underserved communities. The identification of spatial patterns of LBW prevalence is a critical first step in a more complete understanding of the epidemiology of this public health challenge and these techniques are instrumental in designing valid observational and analytical studies to more fully study the problem. This paper examines the spatial patterns of LBW prevalence, as well as the presence of spatial clusters in the State of Georgia at both the county and census tract levels. Unadjusted and empirical Bayes smoothed LBW rates were mapped to visualize the spatial variation of LBW rates, and the Moran’s I statistic and the Local Indicator of Spatial Association (LISA) statistic were computed to assess the degree of spatial dependence in the LBW rates. Results revealed marked geographical variation in LBW prevalence in Georgia in 2000. In addition, these data validate the significant disparity (two-fold difference) between white and black racial subgroups as documented in the literature. Trends associated with positive and negative spatial autocorrelations illustrated variation with respect to race. Limitations of data and methods, as well as plans for utility of the results of this study for further investigation were discussed.