张广才岭五道岭组火山岩的锆石U——Pb 年代学及地球化学特征     

于倩  葛文春  杨浩  邢德和  张彦龙 《世界地质》2013,32(4):707-716

对张广才岭五道岭组火山岩进行锆石U--Pb LA--ICP--MS 年代学和岩石地球化学研究,以确定该组火山岩形成的时代和构造背景。选取样品中的锆石均呈自形--半自形晶,具有清晰的振荡生长环带和较高的Th /U 比值( 0. 52 ～ 2. 28) ,暗示其岩浆成因。测年结果显示,五道岭组火山岩形成于289 ± 3 Ma,是早二叠世岩浆活动的产物。火山岩的岩石组合为玄武岩--流纹岩,显示双峰式火山岩的特点,属于高钾钙碱性--钾玄岩系列,玄武岩具有富集Ｒb、K 等大离子亲石元素( LILE) ,亏损Nb、Ta 等高场强元素( HFSE) 的特征; 流纹岩呈负铕异常,富集Ｒb、Th、U 和K 等大离子亲石元素( LILE) ,亏损Nb、Ta 和Ti 等高场强元素( HFSE) 及Sr、P 元素,并显示A 型流纹岩的特点。结合该时期区域构造演化史,火山岩地球化学特征揭示了五道岭组火山岩的形成与岛弧环境下的局部伸展作用有关,这种构造背景是古亚洲洋板块俯冲于松嫩-张广才岭-佳木斯陆块之下造成的。  相似文献   

高校“地图学”课程思政元素挖掘与课堂融入     

黄翌  陈建伟  刘潇潇  王梦琦 《测绘与空间地理信息》2022,45(1):19-21

高校专业课的课程思政建设是高校思想政治工作的基本载体。“地图学”是测绘工程、遥感科学与技术、地理信息科学、地理科学等本科专业的基础课,在测绘、地理等学科的课程思政建设中具有基础性地位。本文依据教学实践,归纳了地图学课程中与课程思政相结合的知识点,并介绍了在教学中如何巧妙、潜移默化地融入思政元素,在地图学课程教学过程中做到能力培养和素质提升共同进步。  相似文献   

256层多排螺旋CT小肠成像(MDCTE)对小肠疾病的诊断价值     

窦娅芳  唐颖  解骞  朱全东  祝瑞江  梁宗辉 《CT理论与应用研究》2013,(1):137-146

目的:探讨256层多排螺旋CT小肠造影(MDCTE)扫描技术在小肠疾病诊断中的临床应用价值。材料和方法:对118例临床怀疑小肠疾病患者,男53例,女65例,平均年龄48.5岁。行256-MDCTE平扫及增强扫描,通过横断面及多平面重建,观察病变部位、大小、形态、周围侵犯及转移情况,结果与最终临床诊断对照分析。结果:本组118例患者中,56例MDCTE诊断为小肠病变,并与最终临床诊断相符。另外62例MDCTE诊断为阴性,其中47例符合,9例漏诊,6例误诊。并且通过统计分析得出MDCTE对小肠疾病诊断的灵敏度为78.87%(56/71),特异度为100%(47/47),正确率为87.29%((56+47)/118),阳性预测值为100%(56/56),阴性预测值为75.80%(47/62)。结论:小肠肿瘤、炎症、肠梗阻等病变在MDCTE上具有特征性的表现,MDCTE对小肠疾病的临床诊治具有重要价值。  相似文献   

摩擦钢板接触面对软钢耗能节点工作性能影响     

董宏英  沈松  曹万林  张建伟  王立长 《世界地震工程》2013,(1):114-119

根据大连国际会议中心结构的设计特点,设计了2个带弧形接触板的软钢耗能节点试件,并进行了该类型试件在低周反复荷载下的抗震性能试验研究,试验模型为原型。在试验基础上,探讨了2个试件软钢耗能节点的承载力、刚度及其退化过程、延性、滞回特性和破坏特征。给出了软钢板耗能节点的承载力计算方法,计算结果与试验结果符合较好。研究表明,采用18mm厚软钢连接板节点试件具有较好的变形能力和耗能能力。  相似文献   

我国标贯液化判别方法对黄土适用性研究     

董林  王峻  夏坤  王谦 《地震工程与工程振动》2013,33(2)

鉴于我国20世纪50年代以来,地震液化现场很少有黄土液化的实例,而饱和黄土甚至高含水率的黄土也具有很高的液化势和流态破坏势.为工程设计准确预测饱和黄土在设计地震动的作用下是否会液化,本文用Seed-Idriss简化判别法对兰州某民用机场的饱和黄土和砂土进行液化判别,并以此结果为依据检验规范判别式对黄土液化判别的适用性.结论证实用Seed-Idriss简化判别法结果检验规范方法对黄土的适用性是可行的,规范方法对于黄土液化判别过于保守.  相似文献   

Investigating the uncertainty and transferability of parameters in SWAT model under climate change     

Qian Zhu  Xujie Zhang  Chong Ma  Chao Gao 《水文科学杂志》2013,58(5):914-930

ABSTRACT

There is an implicit assumption in most work that the parameters calibrated based on observations remain valid for future climatic conditions. However, this might not be true due to parameter instability. This paper investigates the uncertainty and transferability of parameters in a hydrological model under climate change. Parameter transferability is investigated with three parameter sets identified for different climatic conditions, which are: wet, intermediate and dry. A parameter set based on the baseline period (1961–1990) is also investigated for comparison. For uncertainty analysis, a k-simulation set approach is proposed instead of employing the traditional optimization method which uses a single best-fit parameter set. The results show that the parameter set from the wet sub-period performs the best when transferred into wet climate condition, while the parameter set from the baseline period is the most appropriate when transferred into dry climate condition. The largest uncertainty of simulated daily high flows for 2011–2040 is from the parameter set trained in the dry sub-period, while that of simulated daily medium and low flows lies in the parameter set from the intermediate calibration sub-period. For annual changes in the future period, the uncertainty with the parameter set from the intermediate sub-period is the largest, followed by the wet sub-period and dry sub-period. Compared with high and medium flows/runoffs, the uncertainty of low flows/runoffs is much smaller for both simulated daily flows and annual runoffs. For seasonal runoffs, the largest uncertainty is from the intermediate sub-period, while the smallest is from the dry sub-period. Apart from that, the largest uncertainty can be observed for spring runoffs and the lowest one for autumn runoffs. Compared with the traditional optimization method, the k-simulation set approach shows many more advantages, particularly being able to provide uncertainty information to decision support for watershed management under climate change.