CT在新型冠状病毒肺炎诊断与鉴别诊断中的应用价值     

陈钊  王荣福 《CT理论与应用研究》2020,29(3):273-279

新型冠状病毒肺炎已在全世界多个国家暴发,如何提升早期筛查率成为疫情防控的重点。计算机断层扫描（CT）在中国新冠肺炎的早期筛查及疾病监测中发挥了重要作用,因此,提升广大影像医生对肺炎诊断的准确性尤其重要。本文旨在述评CT在新冠肺炎筛查中的应用价值、诊断及鉴别诊断要点,比较新冠肺炎与其他病毒性肺炎、细菌性肺炎等的CT表现差别,以期在今后的疫情防控中CT可以发挥更好的作用,帮助即早发现并隔离病患。   相似文献   

Ordovician Proto–basin in South China and its Tectonic Implications: Evidence from the Detrital Zircon U–Pb Ages of the Ordovician in Central Hunan, China     

ZHANG Jibiao  NI Jingbo  LIU Yanxue  ZHANG Heng  BU Ling 《《地质学报》英文版》2020,94(6):2115-2133

Caledonian orogeny is another important tectonic event in South China Block after the breakup of the Rodinia supercontinent. With a view to constrain the tectonic evolution and proto–basin in South China, this paper reports the geochemical and zircon U-Pb dating data of the Ordovician strata in central Hunan, South China. Geochemical features and paleocurrent directions suggest that the lower Ordovician deposited in a passive continental margin basin with a provenance of quartzose components and showing an affinity with the Yangtze Block. U-Pb age data for 260 detrital zircons from upper Ordovician identify three major age populations as: 900–1200 Ma, 1400–1800 Ma and 2400–2700 Ma. The detrital zircon age spectrum as well as the paleocurrent directions suggest that upper Ordovician deposited in a foreland basin and showing a close affinity with the Cathaysia Block. It is also suggest that the lower Ordovician continuously accepted the mineral from the Yangtze Block, whereas the provenance of the upper Ordovician sedimentary basin changed from the Yangtze Block to the Cathaysia Block. This change implies a tectonic movement, which caused the transformation of the proto–basin in the Hunan area in SCB from passive continental margin basin to foreland basin probably took place during late Ordovician. This fact also demonstrate that the Caledonian orogeny in South China Block began no later than 453 Ma, and a new crustal evolution model is proposed.  相似文献   

淮河上游干流径流量对不同气候要素变化的响应研究   总被引：1，自引：0，他引：1  

薛颖  高超  张勋  许莹  李鹏 《水文》2017,37(3):22-28

基于淮河流域上游地区8个气象站点1959~2008年日降水量与温度数据,通过改变降水量和温度建立25种气候情景,利用SWIM水文模型,对不同情景下的径流量进行模拟,分析了淮河上游地区径流量对不同气候要素变化的敏感性,有利于该地区旱涝灾害的及时预警。结果表明,淮河流域上游地区,降水量的变化对径流量的影响较大,在仅考虑降水量和温度的情况下,径流量对降水量变化的敏感性系数处在1.7012~2.1358范围内,而对温度变化的敏感性较弱,三个站点径流量对温度变化的敏感性系数处在-0.0499~0.1547范围内;研究区在研究期内降水量变化对径流量的变化贡献较小,由大坡岭向下游依次为-0.0014,-0.0052,-0.0009,温度变化对径流量的贡献较大,由大坡岭向下游依次为0.0828,0.0152,0.0039,径流量对气候要素的响应不仅由其对气候要素变化的敏感性决定,也受到气候要素变化幅度的影响。  相似文献   

南水北调西线一期工程调水区径流量与影响因子关系分析——以达曲为例   总被引：5，自引：2，他引：3  

门宝辉  刘昌明  夏军  刘苏峡 《地理科学》2006,26(6):674-681

以达曲为例,利用朱倭站1961~1996年的水文资料及东谷站的降水量资料,分析南水北调西线一期工程调水区径流量与影响因子的关系,结果表明:年平均气温呈上升趋势,其线性变率为0.24℃/10 a,36年共上升了0.864℃,以20世纪80年代以后上升趋势更为显著;年蒸发量呈增加趋势,其线性变率为+2.78 mm/10 a;年平均降水量及春、冬及非汛期降水逐年增加,其中年平均降水气候倾向率达+5.2 mm/10 a;调水区达曲的年平均径流及春、秋、汛期、非汛期流量呈逐年增加趋势,其中以春季和非汛期尤为明显。虽然气温升高、蒸发量增大,但这不是影响径流的直接因素,其增量还不足以抵消降水对径流的增加,降水是影响调水区径流量多少的主要气候因子。  相似文献