恒星化学元素丰度研究新进展     

张华伟  赵刚 《天文学进展》2000,18(1):56-66

介绍了银河系中各种化学元素丰度随金属丰度的变化规律。结合恒星核合成理论,可以了解银河系的形成和演化过程。另外,某些化学元素丰度存在的弥散可能是恒星形成时银河系环境的不均匀性造成的。  相似文献   

浙南岛屿岩相潮间带大型底栖动物优势种生态位研究          下载免费PDF全文

彭欣  张华伟  唐久  仇建标  陈少波 《海洋学研究》2021,39(1):79-85

本研究利用1990年、2006年、2010年和2016年11月在南麂列岛、北龙-北麂列岛和洞头列岛的调查结果和历史资料,分析了浙南岛屿岩相潮间带大型底栖动物优势种的时空变化及生态位.结果显示:4次调查数据中主要优势种有15种,前4位优势种分别为日本笠藤壶、条纹隔贻贝、疣荔枝螺和小结节滨螺;30 a来日本笠藤壶有逐渐被条...  相似文献   

一种新型电镀法制备的Ir/Ir(OH)_x pH电极及其在加州纽波特港海域的应用研究     

张潇  叶瑛  阚雅婷  黄元凤  贾健君  赵玥  陈镇东  秦华伟 《海洋学报(英文版)》2017,36(5):99-104

Resulting from the rising levels of atmospheric carbon, ocean acidification has become a global problem. It has significant impacts on the development, survival, growth and physiology of marine organisms. Therefore, a highprecision sensor is urgently needed to measure the pH of sea-water. Iridium wire with a diameter of 0.25 mm is used as the substrate, and an Ir/Ir(OH)_x pH electrode is prepared by a one-step electrochemical method in a Li OH solution at the room temperature. A scanning electron microscope(SEM) observation reveals that it is coated with nanoscale particles. In laboratory tests, the electrode exhibits a very promising pH response, with an ideal Nernst slope(56.14–59.52), fast response, good stability and long life-span in tested pH buffer solutions. For a sea trial,four pH electrodes and one Ag/Ag Cl reference electrode are integrated with a self-made chemical sensor, and a profile detection of nearly 70 m is implemented near Newport Harbor, California on August 3, 2015. The results reflect that the pH value measured by the sensor is very close to the data given by Sea-Bird 911 plus CTD, with a difference value ranging from 0.000 075 to 0.064 719. And the sensor shows a better data matching degree in 0–40m water depth. In addition, the high precision and accuracy of the sensor make it possible to use in the ocean observation field.  相似文献   

The Upper Jurassic–Lower Cretaceous of eastern Heilongjiang, northeast China: stratigraphy and regional basin history     

Jingeng Sha  Masaki Matsukawa  Huawei Cai  Baoyu Jiang  Makoto Ito  Chengquan He  Zhiwei Gu 《Cretaceous Research》2003,24(6):715-728

In eastern Heilongjiang, the Upper Jurassic is marine and restricted to the Suibin and Dong’an areas, where it is characterized faunally by Callovian–Volgian (Tithonian) bivalves and florally by dinoflagellates. The Lower Cretaceous is widely distributed in eastern Heilongjiang, and characterized faunally by Berriasian–Valanginian bivalves, Barremian–Albian ammonites and Aucellina, and florally by dinoflagellates. To the west, the marine facies grade into non-marine beds. Thus, in the east, for example in the Dong’an and Dajiashan areas, near the northwestern Palaeo-Pacific, the Lower Cretaceous is marine; westward, in the Yunshan, Longzhaogou, Peide, and Zhushan areas, marine and non-marine deposits alternate, whereas further west still, e.g. in the Jixi Basin, non-marine facies are intercalated with marine beds. This regional distribution is indicative of a large, shallow embayment opening eastwards to the Palaeo-Pacific; during the Early Cretaceous successive transgressive-regressive events influenced the climate and biota of eastern Heilongjiang and northeastern China. Many of the Lower Cretaceous sections contain abundant coals, demonstrating that in this region the Early Cretaceous was an important coal-forming period. Some non-marine bivalve species are common to the Lower Cretaceous Jixi Group of eastern Heilongjiang, the Jehol Group of western Liaoning and the Transbaikalian Group of Siberia, suggesting that these groups are of comparable Early Cretaceous age.  相似文献   

北部湾盆地涠西南凹陷与海中凹陷古近纪沉积关系探讨     

李上卿  牛华伟  郑军  江平  黄建军 《海洋地质译丛》2012,(1):1-6

涠西南凹陷与海中凹陷相邻,油气勘探成果及石油地质条件认识程度不同。通过对地层原始产状的恢复,讨论了涠西南低凸起对两凹陷古近纪沉积环境的阻隔作用,并对古新世和始新世沉积可容空间原型进行了恢复,认为古新世两凹陷局部连通,始新世和渐新世两凹陷全部连通;3号断层作为两凹陷区划边界的一部分,其活动强度控制了沉积可容空间的分布和容积的大小,始新世3号断层活动强度最大,其形成的沉积可容空间也最大,由于两凹陷沉积连通,因此两凹陷始新统生烃能力可以进行类比分析。  相似文献   

Best-Practice Principles of Seismic Imaging for Resource Exploration     

ZHOU Huawei  ZOU Zhihui  ZHANG Jianzhong 《《地质学报》英文版》2019,93(Z2):338-338

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冀北五凤楼煌斑岩年代学、地球化学特征及其成因     

董朋生  董国臣  孙转荣  李华伟  王树树  翟天雷  王伟清  耿建珍 《现代地质》2018,32(2):305

燕山地区中生代花岗岩类侵入体中发育煌斑岩,呈脉状产于冀北寿王坟—五凤楼一带,岩石类型主要为云煌岩。岩石化学属基性,富钠,富碱,高Mg#,高钛,属高钛、钠质钙碱性煌斑岩。岩石中富集LREE、Ba等大离子亲石元素和P,亏损HREE和Nb、Zr、Ta等高场强元素,基本无Eu异常。其LA ICP MS锆石U Pb年龄为(1352±13) Ma, 侵位于早白垩世,与寿王坟杂岩体是同一时期岩浆活动的产物。五凤楼煌斑岩锆石εHf(t)值为-193~-133,模式年龄远老于其成岩年龄,表明岩浆起源于富集地幔。较高的Ba/Th值(12309~43634)和Sr值(9154×10-6~1 257×10-6),暗示源区在一定程度上受到了俯冲带流体的改造;较低的Rb/Sr值(002~011)及较高的Ba/Rb值(108~809)证明其源区含有角闪石。岩石地球化学特征显示,五凤楼煌斑岩由俯冲的古太平洋壳富钠流体交代形成的石榴石角闪二辉橄榄岩富集地幔的低程度(05％~15％)部分熔融上侵而成,起源深度为75~100 km。  相似文献   

地层压力和产水对低渗透气藏气井产能的影响     

汪周华  王子敦  郭平  邓丹  廖华伟 《地质科技情报》2016,(4):133-138

通常情况下,随着地层压力降低,储层渗透率及流体性质的变化会导致气井产能方程随之发生变化。对于低渗透产水气藏,由于应力敏感、紊流效应、滑脱效应等非线性渗流效应及后期产水的影响,气井产能急剧降低。为了定量评价以上因素对气井产能的影响,基于常规二项式产能方程,建立了综合考虑地层压力变化、非线性渗流效应及产水对气井产能影响的产能方程。通过实例计算表明,由于应力敏感、紊流效应、滑脱效应等非线性渗流效应的综合影响,二项式系数A随地层压力的降低而减小,而系数B随地层压力的降低而增大;此外,由于后期产水影响,含水饱和度不断上升,气相相对渗透率随水气比的上升而减小,使二项式系数A、B均随水气比的上升而增大;因此,气井的产能下降幅度随地层压力下降呈线性升高趋势,随水气比下降呈对数降低趋势。该研究成果对于低渗透产水气井的产能预测及分析具有指导作用。  相似文献