64排CT冠脉成像与PET-CT心肌灌注显像对照分析的临床价值

目的:比较64排CT冠脉成像(CTCA)与PET-CT心肌灌注显像(MPI)对相关冠状动脉狭窄,及准确定位"罪犯"血管的价值。方法:回顾性分析内蒙古医科大学附属医院2009年3月到2014年12月,在四周内进行CTCA与MPI的临床确诊及可疑的冠心病(CAD)患者59例,由2名有经验影像与核医学医师进行图像及数据分析,按照冠状动脉节段性供血特点,分析冠状动脉供血区域和心肌节段对应关系,采用Spearman等级相关、Pearson相关和Kappa检验方法。结果:59例患者按照LAD、LCX、RCA三支冠状动脉支配心肌部位来统计,合计177支血管,冠脉血管0级58支;Ⅰ级24支;Ⅱ级33支;Ⅲ级40支;Ⅳ级22支。灌注0分63支;1分30支;2分45支;3分27支;4分12支。三支冠状动脉CTCA与MPI分别行相关性分析和吻合度分析,两者为正性相关,吻合率较高。LAD r=0.764,P=0.000;LCX r=0.593,P=0.000;RCA r=0.831,P=0.000。LAD k=0.666,P=0.000;LCX k=0.601,P=0.000;RCA k=0.589,P=0.000。结论:CTCA的解剖学信息和MPI生理学功能性信息相互结合,有效互补,两者结合能够准确定位CAD患者的"罪犯"血管,大大提高CAD诊断准确率,为临床治疗及预后判断提供有力依据。      

地震下双曲线冷却塔的响应分析

借助ANSYS软件建立双曲线冷却塔的有限元分析模型,讨论自重、风荷载和地震作用下冷却塔的力学性能,通过计算、分析探讨塔筒局部开洞对冷却塔整体及洞口局部强度的影响,主要考虑洞口尺寸和开洞高度对冷却塔整体及洞口局部应力分布规律的影响。结果表明:在一定尺寸范围内,开设洞口对冷却塔的整体强度影响较小,但在洞口局部出现明显的应力集中效应;90 m高度处洞口的应力集中效应低于15 m高度处洞口的应力集中效应,但应力集中效应不容忽视。分析结果为冷却塔结构抗震的设计、加固和施工提供了理论依据和实用的参考建议。     

Clay mineralogy of an Eocene fluvial-lacustrine sequence in Xining Basin,Northwest China,and its paleoclimatic implications

The Eocene was marked by significant cooling during which the global climate was transformed from greenhouse to icehouse conditions. Notable coeval events were the India-Asia collision and the retreat of the Paratethys Sea in Asia. The Eocene section of the long and continuous sedimentary succession of the Xining Basin in Northwest China is characterized by red mudstones with intercalated gypsum and muddy-gypsiferous layers. In this study, we conducted a semi-quantitative analysis of the mineralogy of bulk samples and the clay fraction using X-ray diffraction, with the aim of characterizing the Eocene climatic evolution of the northeastern margin of the Tibetan Plateau and inland Asia. We used a new pretreatment method to address the problem of extracting sufficient clay particles from the gypsum and gypsiferous layers. The bulk mineralogy is dominated by quartz, feldspar, calcite, gypsum and dolomite; and the clay mineralogy is dominated by illite, chlorite, and smectite(including irregular mixed-layer illite-smectite(I/S)). The variations of the clay mineral assemblages indicate the occurrence of alternations between warm humid conditions and hot dry conditions, with relatively high humidity during ～52–50,～41.5–39 and ～35–34 Ma. Comparison of the results with the timing of Tibetan Plateau uplift, transgressions and regressions of the Paratethys Sea, and the marine oxygen isotope record suggest that the Eocene climatic evolution of the study region was driven fundamentally by global climate change.     

孤岛工作面动力灾害预防控制方法研究

为研究孤岛工作面安全开采方法,理论分析其动力灾害多发的岩层运动及应力条件,并提出其安全开采的准则。认为只要合理设计开采参数,就可以避免孤岛工作面动力灾害的发生。分析表明:孤岛工作面长度大于相邻工作面支承压力影响范围之和时,孤岛工作面支承压力无法叠加,工作面较安全;相邻工作面长度大于关键层断裂步距时,覆岩关键层可充分塌垮,孤岛工作面无动压冲击危险;在稳定的内应力场开掘回采巷道时,回采巷道无冲击危险。     

A New Lycopsid, Zhenglia radiata gen. et sp. nov., from the Lower Devonian Posongchong Formation of Southeastern Yunnan, China, and Its Evolutionary Significance

A new plant, Zhenglia radiata gen. et sp. nov., from the Posongchong Formation （Early Devonian, Pragian age） of the Wenshan District of southeastern Yunnan Province, China is a small herbaceous lycopsid. The aerial branches divide into foliar and fertile stems. The arrangement of the leaf bases on the stem shows lepidodendroid-like phyllotaxy. Possibly the leaf base bears a ligulate pit. The microphyll consists of a swollen, decurrent base, and an entire, linear lamina. The fertile axis is composed of sporophylls arranged helically, forming a compact area similar to cone-like structure. Each sporophyll consists of a widened lateral extension and a distal lamina. The ovoid-elongate sporangia are attached adaxially on the surface of sporophylls. Based on morphological similarities, especially the undivided microphylls, the style of phyllotaxy, the form of the cone-like structures and sporangia, the new lycopsid Zhenglia radiata is placed in the order Protolepidodendrales and a possible evolutionary relationship with the arborescent lycopsids of the Late Devonian and Carboniferous is considered.     

南天山及塔里木北缘构造带西段地震构造研究

南天山及塔里木北缘构造带位于帕米尔地区东北侧,地震活动强烈。文中通过地质构造剖面、深部探测资料和地震震源机制解资料,综合研究了该区的地震构造模型。结果认为,该区的构造活动主要表现为天山地块逆冲于塔里木地块之上。天山构造系统包括迈丹断裂及其前缘推覆构造;塔里木构造系统包括深部的塔里木北缘断裂、基底共轭断层和浅部的推覆构造。塔里木北缘断裂是发育于塔里木地壳内部的高角度断裂,其形成原因在于塔里木和天山构造变形方向的差异。塔里木北缘断裂为研究区大地震的主要发震构造,天山推覆构造和塔里木基底断裂系统均具有不同性质的中强地震发震能力     

热带海温异常影响华北夏季降水的机制研究

利用正压涡度方程模式对赤道东太平洋和赤道西太平洋暖池区海温异常影响华北夏季降水的机制进行了研究,结果表明:(1)赤道东太平洋海温升高,西太平洋副高会前期加强,位置异常偏北,后期位置偏东;华东25°N以南多低槽活动,华北上空低槽活动少;华北东部盛行南风,长江中下游盛行北风扰动,不利于水汽向华北输送。这些形势都不利于华北降水。(2)西太平洋暖池区海温降低,副高减弱,不利于华北降水;华北上空多低槽活动,是有利于降水的形势;渤海、朝鲜半岛盛行北风,而贝加尔湖及其东南方向为强南风,冷暖空气不易交汇,华北降水稀少。(3)西太平洋暖池海温降低对华北降水的影响不象赤道东太平洋海温异常那样显著。(4)极涡变化和热带海温异常之间的对应关系不确定。     

X射线粉晶衍射-拉曼光谱法研究含甲烷双组分水合物结构及谱学特征

天然气水合物的晶体结构主要取决于客体分子种类与组成,目前单组分水合物的结构和谱学特征较为明确,但多组分水合物相关研究较少.为解决多组分水合物的结构识别问题,探讨其谱学特征,本文实验合成了甲烷-丙烷(CH4-C3 H8)和甲烷-四氢呋喃(CH4-THF)两种含CH4双组分水合物以及CH4、C3 H8和THF等三种单组分水...     

基于气象遥感Priestly-Taylor模型的蒸散发估算——以天津市蓟州区为例

基于Landsat-8数据,采用遥感Priestly-Taylor模型分别估算蓟州区的净辐射通量以及归一化植被指数,进一步计算蓟州区日蒸散发量.区域蒸散发的遥感反演主要解决以下两个问题:一是遥感地表温度的反演;二是估算各类遥感模型所需的地表参数(叶面积指数、NDVI、地表阻抗等),结合物理模型或者半经验公式估算区域蒸散...