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81.
中国地震前兆台网数据处理系统针对传统的“L”型地电场布极方式而开发的数据处理软件,不能对南京地震台地电场数据有效处理,考虑到地电场的矢量特性,南京地震台取消斜道观测,布设同方向3个测道的多极距地电场观测系统.  相似文献   
82.
Investigation of the deep geophysical structure of the Longmen Mountains tectonic belt and its relation to the Wenchuan Earthquake is important for the study of earthquakes. By using magnetotelluric sounding profiles of the Luqu–Zhongjiang and Anxian–Suining; seismic sounding profiles of the Sichuan Maowen–Chongqing Gongtan, the Qinghai Huashi Gorge–Sichuan Jianyang, and the Batang–Zizhong; and magnetogravimetric data of the Longmen Mountains region, the deep geophysical structure of the Songpan–Ganzi block, the western Sichuan foreland basin, and the Longmen Mountains tectonic belt and their relation was discussed. The eastward extrusion of the Qinghai–Tibet Plateau thrusts the Songpan–Ganzi block upon the Yangtze block, which obstructs the eastward movement of the Qinghai–Tibet Plateau. The Maoxian–Wenchuan, Beichuan–Yingxiu, and Anxian–Guanxian faults of the Longmen Mountains fault belt dip to northwest with different dip angles and gradually converge in the deeper parts. Geophysical structure suggests that an intracrustal low-velocity, low-resistivity, and high-conductivity layer is common between the middle and upper crust west of the Longmen Mountains tectonic belt but not in the upper Yangtze block. The Sichuan Basin has a thick low-resistance sedimentary layer on a stable high-resistance basement; moreover, there are secondary paleohighs and depression structures at the lower part of the western Sichuan foreland basin with characteristic of high magnetic anomalies, whereas the Songpan–Ganzi block has a high resisitivity cover of upper crust and continues to a low-resistance layer. Considering the Longmen Mountains tectonic belt as the boundary, there are Bouguer gravity anomalies of "one belt between two zones." Thus, we infer that there is a corresponding relation between the inferred crystalline basement of the Songpan block and the underlying basin basement of the Longmen Mountains fault belt. Furthermore, there may be an extensive ancient Yangtze block, which is west of the Ruoergai block. In addition, the crust–mantle ductile shear zone under the Longmen Mountains tectonic belt is the main fault, whereas the Beichuan–Yingxiu and Anxian–Guanxian faults at the surface are earthquake faults. The Wenchuan Ms 8.0 earthquake might be attributed to the collision of the Yangtze block and the Qinghai–Tibet Plateau. The eastward obduction of the eastern edge of the Qinghai–Tibet Plateau and eastward subduction of its deeper part under the influence of the collision of the Indian, Pacific, and Philippine Plates with the Eurasia Plate might have caused the Longmen Mountains tectonic belt to cut the Moho and extend to the middle and upper crust; thus, creating high stress concentration and rapid energy release zone.  相似文献   
83.
邵华胜  郑念 《地质论评》2024,70(3):1113-1120
地质学领域科研人员参与科普对地质学科发展、科普高质量发展和经济社会发展有着重要的推动作用。调查结果显示,大多数地质学领域科研人员认可科普的作用和意义,愿意积极参与科普活动。然而,保障力度不够、传播渠道不畅、科普内容不深入、科普能力不均衡问题相对突出。增强地质科研单位科普责任意识,强化相关科协和学会的职能,加强晋升激励、奖酬激励及考核激励体系建设,加大地质科普技能培训和经验交流,引导地质科研人员提升科普能力,是促进地质学领域科研人员参与科普的关键。  相似文献   
84.
采用从1988-1999年的现代技术测定的高精度极移序列EOP(IERS97C04)推导出激发函数χ^m)和美国国家环境预测中心和美国国家大气研究中心(CNEP/NCAR)提供的大气角动量激发函数χp和χib^p,使用几种数据分析方法,分析了大气对极移高频振荡(12-42cpy)激发贡献,复数小波变换和功率谱分析表明,χ^m和χ^p序列在高频段内呈现比较强的谱峰,它们具有相似的谱特征,比较而言,χib^p在这个频率段内比χ^p要弱些,χ^m和χ^p之间的相关系数分别为0.75(逆向)和0.6(顺向),两个序列之间的平方相关谱的估计值分别在0.5-0.9之间(负频)和0.4-0.6(正频),相位谱表明χ^p(AAM)超前x^m一天左右,这些大气是极移高频变化的主要激发源,特别是在逆向运动上具有更大的贡献,由于它们之间位相差和振幅变化的不稳定性,说明可能存在AAM以外的其他激发源,这个问题有待进一步深入研究。χ  相似文献   
85.
分析了单纯用地震波振幅作为报警阈值的缺点,通过数字地震仪与模拟地震仪报警机制的对比,提出用检测周期和振幅相结合的方法来实现地震报警.  相似文献   
86.
分析了单纯用地震波振幅作为报警阈值的缺点,通过数字地震仪与模拟地震仪报警机制的对比,提出用检测周期和振幅相结合的方法来实现地震报警。  相似文献   
87.
In this study, the authors use a political perspective to explore the relative global status of cities in China. Two questions are addressed. Firstly, by using international organizations as the subjects and quantitative analysis of the spatial distribution of their offices, the overall position of Chinese cities in the global distribution of international organizations is estimated. The results show that 22 Chi- nese cities are involved in international political affairs. Beijing, Shanghai and Guangzhou dominate these activities and have high po- litical global-city status. Secondly, through qualitative analysis of Guangzhou City, the authors explore how its status as a center for intemational organizations has been shaped in recent years. The locational decision-making process is analyzed and the factors are demonstrated at both national and city scales. The definition of international organizations as used in this study refers not only to those supranational bodies that have the ability to manage relations across states (such as the European Union), but also those in- ter-governmental organizations (IGOs), international non-governmental organizations (INGOs) and diplomatic representatives and delegations that today also manage and regulate relations between and among states.  相似文献   
88.
Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei (Pg) from Indo-Pacific, Holothuria vagabunda (Hv) from Norwegian Coast, Stichopus tremulu (St) from Western Indian Ocean, and Isostichopus badionotu (Ib) from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans (SC-Fucs). The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer (NMR) and room temperature 13C NMR. The results indicated that Fuc-Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc-Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc-St from the frigid zone and Fuc-Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.  相似文献   
89.
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???ü???????2013??12?°??Ms5.1???????????????????????????????????????о??????????о?300 km??Χ???????????·??????????????仯??????????????2012??????????????????????????????·??????????????????????????????????·????????????????????????????????  相似文献   
90.
南扶273-平253井是大庆油田一口重点实验井,采用全过程欠平衡技术钻进,钻探目的层位是F15油层。在全过程欠平衡钻井作业过程中,通过井下套管阀开关,保证井底始终处于欠平衡状态,成功地进行了欠平衡钻进、不压井起下钻等作业,有效地保护了储层。介绍了应用于该井的全过程欠平衡技术、井眼轨迹控制技术、设备选择以及现场出现过的问题和解决方法等。  相似文献   
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