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Stochastic dynamic model of SARS spreading

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Chinese Science Bulletin 2003年第13期48卷 1287-1292页

作者： SHI Yaolin Computational geodynamics Laboratory of Graduate School of Chinese Academy of Sciences, Beijing 100039, China (e-mail: shiyl@***) Computational geodynamics Laboratory of Graduate School of Chinese Academy of Sciences 100039 Beijing China.

Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte Carlo test. The preliminary results indicate that the time-dependent infection rate is the most important control factor for SARS spreading. The model can be applied to prediction of the course with fluctuations of the epidemics, if the previous history of the epidemics and the future infection rate under control measures are known.

关键词： SARS 非典型肺炎随机过程传染病模型疫情控制

Stress,strain and earthquake activity

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Earthquake Science 2009年第6期22卷 575-578页

作者： Yaolin Shi Laboratory of Computational geodynamics Graduate University of Chinese Academy of Sciences

There are 13 papers in this special issue on stress field, crustal deformation and seismicity. The great Wenchuan earthquake is a grievous disaster, but Chinese scientists are trying to learn more from the event in order to understand better the physics of earthquakes for future hazard mitigation planning. Rapid development of GPS technology provide the possibility in the first time in history to monitor the crustal deformation in a wide range and high accuracy, however, it is an important lesson learned from the Wenchuan earthquake,

关键词： Stress,strain and earthquake activity

Characteristic of Gravity and Magnetic Anomalies in the Daba Shan and the Sichuan basin, China: Implication for Architecture of the Daba Shan

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Acta Geologica Sinica(English Edition) 2013年第4期87卷 1154-1161页

作者： ZHANG Jisheng GAO Rui LI Qiusheng GUAN Ye WANG Haiyan LI Wenhui Institute of geology Chinese academy of geological sciences Earthprobe and geodynamics open laboratory Ministry of land and resources

The Dabashan nappe structural belt links the Hannan block to the west with the Huangling block to the east between Yangxian and Xiangfan. The Dabashan arc-shaped fold belt formed during late Jurassic and was superposed on earlier Triassic folds. To achieve an improved understanding of the deep tectonics of the Dabashan nappe structural belt, we processed and interpreted the gravity and magnetic data for this area using new deep reflection seismic and other geophysical data as constraints. The results show that the Sichuan basin and Daba Mountains lie between the Longmenshan and Wulingshan gravity gradient belts. The positive magnetic anomalies around Nanchong-Tongjiang-Wanyuan-Langao and around Shizhu result from the crystalline basement. Modeling of the gravity and magnetic anomalies in the Daba Mountains and the Sichuan basin shows that the crystalline basement around Nanchong-Tongjiang-Wanyuan-Langao extends to the northeast underneath the Wafangdian fault near Ziyang. The magnetic field boundary in the Zhenba-Wanyuan-Chengkou-Zhenping area is the major boundary of the Dabashan nappe thrusting above the Sichuan Basin. This boundary might be the demarcation between the south Dabashan and the north Dabashan structural elements. The low gravity anomaly between Tongjiang and Chengkou might be partly caused by thickened lower crust. The local low gravity anomaly to the south of Chengkou-Wanyuan might result from Mesozoic strata of low density in the Dabashan foreland depression area.

关键词： Daba Mountains nappe structural belt Sichuan basin gravity anomaly magneticanomaly crystalline basement

Formation of diamond powders from melamine under high pressure and high temperature

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Chinese Physics C 2013年第8期37卷 80-83页

作者：房雷鸣陈喜平 H. Ohfuji T. Irifune 孙光爱陈波彭述明 Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics geodynamics Research Center Ehime University

High pressure pyrolysis of melamine has been attracting great interest recently, due to it being considered as a suitable precursor to realize the g-C3N4 and even superhard C3N4. In this work, we studied the detailed pyrolysis behavior of melamine at 22 GPa. Melamine was stable at 800℃, and decomposed to diamond in the form of powder at 1500-2000 ℃ under this pressure condition. At 2000℃, the pure cubic diamond powders with 0.1 0.5 μm grain size were obtained. The diamond particles exhibited euhedral forms and dispersed to each other, we proposed that these novel features were caused by the presence of liquid N2 and NH3 during diamond formation. The high pressure pyrolysis of melamine may provide a new means of producing micrometer-sized diamond powders.

关键词： melamine decomposition high pressure diamond powder

A VARIATIONAL METHOD FOR COMPUTING POTENTIAL COEFFICIENTS USING DIFFERENT TYPES OF GRAVIMETRIC DATA

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Geo-Spatial Information Science 1998年第1期1卷 60-62页

作者： GUO Junyi[a] [a]Laboratory for Modern geodynamics WTUSM Wuhan China 430079

In this paper,a variational method is presented for solving theclassical gravimetric,satellite gravimetric and satellite altimetric mixed typeboudary value problem to obtain the potential *** to thisprinciple,classical gravimetric data（height measured by geometric levelling orheight triangulation）,satellite gravimetric data（height measured by satellitegeodesy technique）and satellite altimetric data can be used jointly to calculate thepotential coefficients.

关键词： boundary value problem potential coefficient variational method

Recent advances of computing coseismic deformations in theory and applications

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Earthquake Science 2014年第2期27卷 217-227页

作者： Wenke Sun Key Laboratory of Computational geodynamics University of Chinese Academy of Sciences

This paper reviews the recent advances in computing coseismic deformations,and their contributions to seismology and geodesy. At first,an overview on the history of the dislocation theory development is given in the introduction section. Then,emphasis are given on some new developments through few examples in the following sections,such as the new dislocation theory for a 3D Earth model,a new computing scheme on coseismic deflection change of vertical,the relation of dislocation Love number and the conventional Love numbers,the application of dislocation theory applied in satellite gravity observations,the coseismic deformations observed by GRACE,and a new method to determine dislocation Love numbers by GRACE. Furthermore,some advanced theoretical and cases studies are introduced to illustrate how dislocation theory is important in interpret geodetic data,or invert seismic slip for co- and post-seismic processes,using seismic and geodetic data. Final remarks are given in the last section,with discussions,conclusions,comments on existing problems,and expected methods to solve them.

关键词： Dislocation theory Coseismic deformations Earthquake Displacement Gravity Modern geodesy

Dynamics of thinning and destruction of the continental cratonic lithosphere: Numerical modeling

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Science China Earth Sciences 2018年第7期61卷 823-852页

作者： Mingqi LIU Zhonghai LI Key Laboratory of Computational geodynamics College of Earth and Planetary Sciences University of Chinese Academy of Sciences Institute of Geology Chinese Academy of Geological Sciences

Thinning of the cratonic lithosphere is common in nature, but its destruction is not. In either case, the mechanisms for both thinning and destruction are still widely under debate. In this study, we have made a review on the processes and mechanisms of thinning and destruction of cratonic lithosphere according to previous studies of geological/geophysical observations and numerical simulations, with specific application to the North China Craton(NCC). Two main models are suggested for the thinning and destruction of the NCC, both of which are related to subduction of the oceanic lithosphere. One is the "bottom-up" model, in which the deeply subducting slab perturbs and induces upwelling from the hydrous mantle transition zone(MTZ). The upwelling produces mantle convection and erodes the bottom of the overriding lithosphere by the fluid-meltperidotite reaction. Mineral compositions and rheological properties of the overriding lithospheric mantle are changed, allowing downward dripping of lithospheric components into the asthenosphere. Consequently, lithospheric thinning or even destruction occurs. The other is the "top-down" model, characterized by the flat subduction of oceanic slab beneath the overriding cratonic lithosphere. Dehydration reactions from the subducting slab would significantly hydrate the lithospheric mantle and decrease its rheological strength. Then the subduction angle may be changed from shallow to steep, inducing lateral upwelling of the asthenosphere. This upwelling would heat and weaken the overriding lithospheric mantle, which led to the weakened lithospheric mantle dripping into the asthenosphere. These two models have some similarities, in that both take the subducting oceanic slab and relevant fluid migration as the major driving mechanism for thinning or destruction of the overriding cratonic lithosphere. The key difference between the two models is the effective depth of the subducting oceanic slab. One is stagnation and flattening in t

关键词： Lithospheric thinning Cratonic destruction Big mantle wedge Plate subduction Fluid migration Numericalmodeling

Characteristics of gravity signal and loading effect in China

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Geodesy and geodynamics 2015年第4期6卷 280-285页

作者： Yi Shuang Sun Wenke Key Laboratory of Computational geodynamics University of Chinese Academy of Sciences

The complex geographical environment in China makes its gravity signals *** work gives a comprehensive representation and explanation in secular trend of gravity change in different regions,the key features of which include positive trend in inner Tibet Plateau and South China and negative trend in North China plain and high mountain Asia（HMA）.We also present the patterns of amplitudes and phases of annual and semiannual *** mechanism underlying the semiannual period is explicitly *** displacement in three directions expressed in terms of geo-potential spherical coefficients and load Love numbers are given.A case study applied with these equations is *** results show that Global Positioning System（GPS） observations can be used to compare with Gravity Recovery and Climate Experiment（GRACE） derived displacement and the vertical direction has a signal-noise-ratio of about one order of magnitude larger than the horizontal directions.

关键词： Gravity change Loading effect Gravity Recovery and Climate Experiment (GRACE)Load love number Global Positioning System (GPS) Seasonal variation Gravity trend in China Comparison of GRACE and GPS

Using large dynamite shots to image the structure of the Moho from deep seismic reflection experiment between the Sichuan basin and Qinling orogen

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Earthquake Science 2016年第6期29卷 321-326页

作者： Hongqiang Li Rui Gao Haiyan Wang Wenhui Li Xiaosong Xiong Key Laboratory of Earthprobe and geodynamics MLRInstitute of GeologyChinese Academy of Geological Sciences

The Qinling orogen was formed as a result of the collision between the North and South China blocks. The Qinling orogen represents the location at which the southern and northern parts of the Chinese mainland col- lided, and it＇s also the intersection of the Central China orogen and the north-south tectonic belt. There is evidence of strong deformation in this orogen, and it has had a long and complex geological history. We investigated the structure of the Moho in the southern Qinling orogen using large dynamite shot imaging techniques. By integrating the analysis of the single-shot and the move-out corrections profile, we determined the structure of the Moho beneath the northern Dabashan thrust belt and the southern Qinling orogen, including the mantle suture beneath Fenghuang mountain. The Moho is divided into two parts by the mantle suture zone beneath Fenghuang mountain：（1） from Ziyang to Hanyin, the north-dipping Moho is at about 45-55 km depth and the depth increases rapidly; and （2） from Hanyin to Ningshan, the south-dipping Moho is at about 40-45 km depth and shallows slowly. The mantle suture is located beneath Fenghuang mountain, and the Moho overlaps at this location： the shallower Moho is connected to the northern part of China, and the deeper Moho is connected to the southern part. This may indicate that the lithosphere in the Sichuan basin subducts to the Qinling block and that the subduction frontier reaches at least as far as Fenghuang mountain.

关键词： Moho . Deep seismic reflection profiles . Largedynamite shots .Qinling Orogen China