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pn-wave velocity and anisotropy of the western Sichuan and Longmen Mountain region,China

Science China Earth Sciences 2010年第11期53卷 1665-1670页

作者： Xu Yi Li ZhiWei Huang RunQiu Liu JianHua Liu JinSong Chinese Acad Sci Inst Geol & Geophys Key Lab Petr Resources Res Beijing 100029 Peoples R China Chengdu Univ Technol State Key Lab Geohazard Prevent & Geoenvironm Chengdu 610059 Peoples R China

pn-wave velocity and anisotropy beneath the western Sichuan and adjacent region are inverted by a tomography method using arrival data from earthquakes recorded by the Sichuan Earthquake Network. It is followed by an analysis of the uppermost mantle structure of the Longmen Mountain region and the deep tectonics of the Ms8.0 earthquake in Wenchuan. Our results reveal a prominent velocity contrast across the Longmenshan fault: low velocities in the Songpan-Ganzi mountain range and high velocities in the Sichuan basin. They indicate that the Songpan-Ganzi mountain range is underlain by a weak uppermost mantle, which is easy to create ductile flow, whereas the Sichuan basin has a mechanically strong uppermost mantle. These features reflect a difference of the lithospheric mantle beneath tectonically active mountain range and stable basin. The boundary between the high and low velocities is coincident with the Longmenshan fault. Bordered by Wenchuan, the northern part of the boundary is parallel to the fault belt and aftershock distribution, but the southern part of the boundary deviates from the fault belt and is bent toward the Sichuan basin. The Ms8.0 earthquake in Wenchuan is located at the flexural part between them, where a strong heterogeneity is shown in the velocity variation across and parallel to the boundary. This area is reasonably believed as a potential location for regional stress accumulation and release in the Longmen Mountain region, reflecting a prominent character in the deep structure around Wenchuan. pn-wave anisotropy reveals the mantle flow that is consistent with the eastward movement of the Tibetan Plateau. This process provided deep dynamic sourse for tectonic deformation in the Longmen Mountain region and for the occurrence of the Wenchuan Ms8.0 earthquake, but it is clearly affected by the strong lithosphere of the Sichuan basin. There is no correlation between the pn-wave anisotropy and the Longmenshan fault, hence, this fault system is on

关键词： western Sichuan Longmen Mountain pn velocity anisotropy Wenchuan earthquake

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Fine structure of pn velocity beneath Sichuan-Yunnan region

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Science China Earth Sciences 2003年第Z2期46卷 201-209页

作者： HUANG Jinli (黄金莉) SONG Xiaodong (宋晓东) WANG Suyun (汪素云) Center for Analysis and Prediction China Seismological Bureau Beijing 100036 China Center for Analysis and Prediction China Seismological Bureau Beijing 100036 China Department of Geology University of Illinois Urbana IL 61801 USA Institute of Geophysics China Seismological Bureau Beijing 100081 China

We use 23298 pn arrival-time data from Chinese national and provincial earthquake bulletins to invert fine structure of pn velocity and anisotropy at the top of the mantle beneath the Sichuan-Yunnan and its adjacent region. The results suggest that the pn velocity in this region shows significant lateral variation; the pn velocity varies from 7.7 to 8.3 km/s. The pn-velocity variation correlates well with the tectonic activity and heat flow of the region. Low pn velocity is observed in southwest Yunnan , Tengchong volcano area, and the Panxi tectonic area. These areas have very active seismicity and tectonic activity with high surface heat flow. On the other hand, high pn velocity is observed in some stable regions, such as the central region of the Yangtze Platform; the most pronounced high velocity area is located in the Sichuan Basin, south of Chengdu. pn anisotropy shows a complex pattern of regional deformation. The pn fast direction shows a prominent clockwise rotation pattern from east of the Tibetan block to the Sichuan-Yunnan diamond block to southwest Yunnan, which may be related to southeastward escape of the Tibetan Plateau material due to the collision of the Indian Plate to the Eurasia Plate. Thus there appears to be strong correlation between the crustal deformation and the upper mantle structure in the region. The delay times of events and stations show that the crust thickness decreases from the Tibetan Plateau to eastern China, which is consistent with the results from deep seismic sounding.

关键词： Sichuan-Yunnan region, pn velocity, Seismic tomography.

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Discussion on origin of pn velocity variation in China and adjacent region

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Acta Seismologica Sinica(English Edition) 2004年第1期17卷 1-11页

作者： PEI Shun-ping(裴顺平) XU Zhong-huai(许忠淮) WANG Su-yun(汪素云) Computational Geodynamics Laboratory Department of Geophysics Peking University Beijing 100871 China Institute of Geophysics China Seismological Bureau Beijing 100081 China Institute of Geophysics China Seismological Bureau Beijing 100081 China

pn velocity lateral variation and anisotropy images were reconstructed by adding about 50 000 travel times from the regional seismic networks to the datum set of near 40 000 travel times from National Seismic Network of China used by WANG, et al. We discussed the relation of pn velocity variation to Moho depth, Earths heat flow, distribution of Cenozoic volcanic rock and the result of rock experiment under high pressure and high temperature. The result of quantitative analysis indicates that pn velocity is positively correlated with the crust thickness and negatively correlated with the Earths heat flow. Two linear regression equations, one between pn velocity and crust thickness, and the other between pn velocity and heat flow, were obtained. The rate of variation of pn veloc-ity vP with pressure P, Pv/p, estimated from the velocity variation with crust thickness Hv/p, is close to the result obtained from the rock experiment under high pressure and high temperature. If the effect of crust thick-ness on pn velocity is deducted from the velocity variation, then the low pn velocity beneath Qinghai-Xizang pla-teau is more notable. The low pn velocity regions well agree with the Cenozoic volcanic rock. In the several re-gions with significant anisotropy, the direction of fast pn velocity is consistent with the orientation of maximum principal crustal compressive stress, and also with the direction of present-day crustal movement. It indicates that the fast pn velocity direction may be related to the deformation or flow of top mantle material along the direction of maximum pressure.

关键词： pn tomography anisotropy China and adjacent region

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Vector grammars and pn machines

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Science China(Technological Sciences) 1996年第1期39卷 50-60页

作者：蒋昌俊 Department of Computer Science Shandong Institute of Mining and TechnologyTaian 271019 Institute of Automation Chinese Academy of SciencesBeijing 100080China

The concept of vector grammars under the string semantic is *** dass of vector grammars is given,which is similar to the dass of Chomsky *** regular vector grammar is divided *** strong and weak relation between the vector grammar and scalar grammar is discussed,so the spectrum system graph of scalar and vector grammars is *** equivalent relation between the regular vector grammar and Petri nets (also called pn machine) is *** hybrid pn machine is introduced,and its language is proved equivalent to the language of the context-free vector *** the perfect relation structure between vector grammars and pn machines is formed.

关键词： vector grammar pn machine language.

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Velocity structure of uppermost mantle beneath North China from pn tomography and its implications

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Science China Earth Sciences 2003年第Z2期46卷 130-140页

作者： WANG Suyun (汪素云) XU Zhonghuai (许忠淮) PEI Shunping (裴顺平) Institute of Geophysics China Seismological Bureau Beijing 100081 China Institute of Geophysics China Seismological Bureau Beijing 100081 China Institute of Geophysics China Seismological Bureau Beijing 100081 China

20301 pn arrival time data are collected from the seismological bulletins of both national and regional seismic networks. pn travel time residuals are tomographically inverted for the pn velocity structure of uppermost mantle beneath North China. The result indicates that the average pn velocity in North China is 7.92 km/s, and the velocity varies laterally from ?0.21 to +0.29 km/s around the average. The approximately NNE trending high and low velocity regions arrange alternatively west-eastward. From west to east we can see high velocity in the middle Ordos region, the Shanxi graben low, the Jizhong depression high, the west Shandong uplift and Bohai Sea low, and the high velocity region to the east of the Tanlu fault. In the southern boundary zone of the North China block, except for the high velocity in the Qingling Mountains region, the velocity is generally lower than the average. Obvious velocity anisotropy is seen in the Datong Cenozoic volcanic region, with the fast velocity direction in NNE-SSW. Notable velocity anisotropy is also seen around the Bay of Bohai Sea, and the fast velocity directions seem to show a rotation pattern, possibly indicating a flow-like deformation in the uppermost mantle there. The pn velocity variations show a reversed correlation with the Earth's heat flow. The low pn velocity regions generally show high heat flow, e.g., the Shanxi graben and Bohai Sea region. While the high pn velocity regions usually manifest low heat flow, e.g., the region of Jizhong depression. This indicates that the pn velocity variation in the study region is mainly aroused by the regional temperature difference in the uppermost mantle. Strong earthquakes in the crust tend to occur in the region with the abnormal low pn velocity, or in the transition zone between high and low pn velocity regions. The earthquakes in the low velocity region are shallower, while that in the transition zone are deeper.

关键词： North China, pn velocity, seismic tomography, Earth's heat flow, earthquake focal depth.

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Spatial and temporal variation of particulate organic carbon in the pn section of East China Sea

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Acta Oceanologica Sinica 2005年第5期24卷 89-99页

作者： ZHU Zhuoy WU Ying ZHANG Jing WEI Hao State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China College of Chemistry and Chemical Engineering Ocean University of China Qingdao 266003 China Physical Oceanography Laboratory Ocean University of China Qingdao 266003 China

Variations of the particulate organic carbon and nitrogen （POC/pn） along the pn section in the East China Sea （ECS） were examined based on POC/pn data obtained in September 2002. A comparison with others work indicates that POC is the highest in summer, followed by autumn and spring, and the lowest in winter. Generally, POC concentration decreases seawards, and the in situ productivity in September plays an important role in POC distribution. POC in the pn section is composed of terrestrial, resuspended, in situ produced carbon and carbon originated fi＇om the Kuroshio waters. The Changjiang River effects the ECS in the pn section, but the influence is mainly minimiged beyond 123.5° E because of barrier effect. The impact of Kuroshio subsurface water （KSSW） over shelf break can also effect POC distribution, with high POC concentration there.

关键词： POC pn East China Sea pn section

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＂periodic Table" Classification Method Using Three Parameters"Z1/ZT/pn" for Organic Compounds

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Chinese Chemical Letters 1996年第11期7卷 1065-1066页

In this paper, the 'perlodic table(PT) classification method (PTCM)using three parameters'N1/Zr/Pa' for organic compounds has been presented. About 640 classes of compounds have been classified by PTCM.

关键词： pn ZT

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pn结带-带隧道电容的理论与实验研究

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红外研究(A辑) 1987年第2期6 A卷 81-86页

作者：林和汤定元中国科学院上海技术物理研究所

由pn结带-带隧道电流理论出发推导出隧道电容的理论表达式,采用这一表达式对强简并窄禁带Hg1-xCdxTepn结的电容特性进行了拟合计算,计算结果在正偏压及反向小偏压范围内与实验结果拟合得较好。

关键词：电容表达式 pn 隧道效应隧道电流价带能带结构

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Electrical nonlinearity in silicon modulators based on reversed pn junctions

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Photonics Research 2017年第2期5卷 124-128页

作者： SHENG YU TAO CHU State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences College of Information Science and Electronic Engineering Zhejiang University

The electrical nonlinearity of silicon modulators based on reversed pn junctions was found to severely limit the linearity of the *** effect,however,was inadvertently neglected in previous *** the electrical nonlinearity in simulation,a 32.2 dB degradation in the CDR3(i.e.,the suppression ratio between the fundamental signal and intermodulation distortion)of the modulator was observed at a modulation speed of 12 GHz,and the spurious free dynamic range was simultaneously degraded by 17.4 *** was also found that the linearity of the silicon modulator could be improved by reducing the series resistance of the pn *** frequency dependence of the linearity due to the electrical nonlinearity was also investigated.

关键词： pn Electrical nonlinearity in silicon modulators based on reversed pn junctions SFDR CDR MZM IMD EN

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Effect of the Transient Response in Si/Ge Parallelizing pn Junction

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Journal of Materials Science & Technology 1999年第4期15卷 383-383页

作者： Weiqi HUANGt and Chaogang CHEN(Department of Physics, Guizhou Educational College, Guiyan 550003, China)Ergang CHEN(Department of Physics, Yunnan University, Kunming 650091, China)To whom correspondence should be addressed Department of Physics Guizhou Educational College Guiyan 550003 China Department of Physics Yunnan University Kunming 650091 China

There are some new results about photovoltaic transient response in the new effect. We suggest a theoretical model to explain the effect reasonably. The theoretical calculation results agree with that in experiments.

关键词： pn Si Ge Effect of the Transient Response in Si/Ge Parallelizing pn Junction

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