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Resolving rupture processes of great earthquakes: Reviews and perspective from fast response to joint inversion

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Science China Earth Sciences 2020年第4期63卷 492-511页

作者： Han YUE yong ZHANG Zengxi ge Teng WANG Li ZHAO School of Earth and Space Sciences Peking UniversityBeijing 200871China

Resolving rupture processes of great earthquakes has fundamental importance to the study of earthquake physics,rupture dynamics, fault zone structure, and evolving processes. It also plays an essential role in earthquake hazard estimation,emergency response and seismic hazard mitigation. This paper reviews the major progress of the earthquake rupture process studies in the last decades, with an emphasize on the research directions of the department geophysics of Peking University including real-time response, back-projection techniques, geodetic data analysis, joint inversion and inversion in complex earth medium. We discussed the advantages and limitations of tradition methods;proposed a systematic and integrated approach from fast-response to detailed study. We also raised perspectives of using source models for ground motion prediction and the possibility of full-dynamic inversion.

关键词： Finite fault model Backprojection Joint inversion Strong motion Simulation

Soil Microbial Community Structure in Diverse Land Use Systems:A Comparative Study Using Biolog,DGge,and PLFA Analyses

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Pedosphere 2008年第5期18卷 653-663页

作者： XUE Dong YAO Huai-Ying ge De-yong HUANG Chang-yong Key Laboratory of Polluted Environment Remediation and Ecological Health Ministry of Education College of Environmental and Resource Sciences Zhejiang University Huajiachi Campus Hangzhou 310029 （China）. Department of Environmental and Chemical Engineering Luoyang Institute of Science and Technology Luoyang 471023 （China）

Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGge）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems （8-, 50-, and 90- year-old tea gardens）, an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development （AWCD） of all carbon sources and the functional diversity based on the Shannon index decreased （P 〈 0.05） in the following order： wasteland 〉 forest 〉 tea garden. For the DCCE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Cram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.

关键词： Biolog DCCE microbial community structure PLFA tea garden soil

Load Dependence of Nanohardness in Nitrogen Ion Implanted Ti6Al4V Alloy and Fractal Characterization

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Journal of China University of Mining and Technology 2007年第3期17卷 363-367页

作者： LUO yong ge Shi-rong Institute of Trlbology and Rehability Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China School of Mechanical and Electrical Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

Three different nitrogen ion doses were implanted into a Ti6A14V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy （XPS）. Nano-indentation tests were carried out on the surface of the Ti6A14V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6A14V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6A14V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6A14V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.

关键词： nanohardness nano-indentation ion implantation

Study on jet formation behavior and optimization of trunconical hypercumulation shaped charge structure

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Defence Technology（防务技术） 2023年第3期21卷 196-206页

作者： Chao ge Zhuojun Qu Jin Wang Die Hu yong Zhang School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China

Combining the methods of theoretical,numerical and experimental,this research focuses on the jet formation behavior and optimization of trunconical hypercumulation shaped charge *** the three-stage division,formation theory of trunconical hypercumulation shaped charge jet is established based on micro element *** dimensional analysis,main control parameters are identified and their effect on jet formation are *** numerical modelling and orthogonal optimization method,influence of the factors and their levels over the indicators of jet tip velocity and jet length as well as order of the significance of each factor and level are *** experiments of trunconical hypercumulation shaped charge based on the orthogonal optimization reveals its advantage over traditional conical shaped charge structure,and finally determines the optimal influence factor level *** research and results would provide useful guide for the design and application of trunconical hypercumulation shaped charge structure.

关键词： structure shaped charge

Human-induced pluripotent stem cell-derived neural stem cell exosomes improve blood-brain barrier function after intracerebral hemorrhage by activating astrocytes via PI3K/AKT/MCP-1 axis

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Neural Regeneration Research 2025年第2期20卷 518-532页

作者： Conglin Wang Fangyuan Cheng Zhaoli Han Bo Yan Pan Liao Zhenyu Yin Xintong ge Dai Li Rongrong Zhong Qiang Liu Fanglian Chen Ping Lei Department of geriatrics Tianjin Medical University General HospitalTianjinChina School of Medicine Nankai UniversityTianjinChina Tianjin Neurological Institute TianjinChina

Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor ***-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)have shown potential for brain injury repair in central nervous system *** this study,we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying *** results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits,enhanced blood-brain barrier integrity,and reduced leukocyte infiltration in a mouse model of intracerebral ***,hiPSC-NSC-Exos decreased immune cell infiltration,activated astrocytes,and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1,macrophage inflammatory protein-1α,and tumor necrosis factor-αpost-intracerebral hemorrhage,thereby improving the inflammatory *** sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion,thereby improving blood-brain barrier *** with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these *** summary,our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity,in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.

关键词： AKT astrocyte blood-brain barrier cerebral edema exosomes human-induced pluripotent stem cells intracerebral hemorrhage neural stem cells neuroinflammation PI3K

Structural Damage Detection Method Based on Decomposition of the Operating Deflection Shapes

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Chinese Journal of Mechanical Engineering 2011年第3期24卷 480-486页

作者： zang Chaoping College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Full-field measurement techniques such as the scanning laser Doppler vibrometer （LDV） and the electronic speckle pattern interferometry systems can provide a dense and accurate vibration measurement on structural operating deflection shape （ODS） on a relatively short period of *** possibility of structural damage detection and localization using the ODS looks likely more attractive than when using traditional measurement techniques which address only a small number of discrete *** paper discusses the decomposition method of the structural ODSs in the time history using principal component analysis to provide a novel approach to the structural health monitoring and damage *** damage indicator is proposed through comparison of structural singular vectors of the ODS variation matrixes between the healthy and damaged stages.A plate piece with a fix-free configuration is used as an example to demonstrate the effectiveness of the damage detection and localization using the proposed *** simulation results show that：（1） the dominated principal components and the corresponding singular vectors obtained from the decomposition of the structural ODSs maintain most of all vibration information of the plate,especially in the case of harmonic force excitations that the 1st principal component and its vectors mostly dominated in the system;（2） the damage indicator can apparently flag out the damage localization in the case of the different sinusoidal excitation frequencies that may not be close to any of structural natural *** successful simulation indicates that the proposed method for structural damage detection is novel and *** also indicates the potentially practical applications in industries.

关键词： damage detection decomposition operating deflection shape (ODS) principal component

ROBUST DESIGN OF A TWO DEGREE FREEDOM *** TO THE PARAMETER UNCERTAINTY

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Chinese Journal of Mechanical Engineering 2008年第6期21卷 30-35页

作者： zang Chaoping College of Energy and Power Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

A method based on the robust design optimization is presented to handle the structural uncertainty problems. The variations caused in dynamic performance can be expressed by the mean response and the standard deviation of the performance. The robust optimization approach, based on a multi-objective and non-deterministic method, attempts to both optimize the mean performance and minimize the variance of the performance simultaneously. The best possible design optimization is chosen by a trade-off decision. An example of robust design of a two degree freedom system is used to effectively illustrate the application in dynamics. The mass and stiffness uncertainty in the main system as well as the uncertainty of the mass, stiffness and damping in the absorber are considered all together in order to minimize the displacement response of the main system within a wide band of excitation frequencies. The robust optimization results show a significant improvement in performance compared with the conventional solution recommended from vibration textbooks. It is indicated that robust design methods have great potential for application in structural dynamics to deal with uncertainty problems.

关键词： Robust design Optimization Dynamics

Method of GIL partial discharge localization based on natural neighbour interpolation and ECOC‐MLP‐SVM using optical simulation technology

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High Voltage 2021年第3期6卷 514-524页

作者： Yiming zang yong Qian Hui Wang Antian Xu gehao Sheng Xiuchen Jiang Department of Electrical Engineering Shanghai Jiao Tong UniversityShanghaiChina Department of Light Sources and Illuminating Engineering Fudan UniversityShanghaiChina

Partial discharge(PD)is one of the main causes rendering the deterioration of the insulation state in gas‐insulated transmission line(GIL).Accurate and timely localization of the PD source is essential to ensure the safe and stable operation of the *** present,optical PD detection technology shows advantages in terms of high sensitivity and strong anti‐inter-ference ***,an optical PD localization method based on optical simulation fingerprint database is *** introduction of simulation conquers the difficulty of obtaining a PD fingerprint database in field *** method con-structs a simulation fingerprint database by performing PD simulation in a GIL simulation model of the same size as the actual *** natural neighbour interpolation algorithm is applied to expand the simulation fingerprint database to cover all locations in the *** two‐level localization method proposed is to match the PD fingerprint to be tested with the expanded fingerprint database,which can reduce the amount of calculation while main-taining the localization *** experimental results show that the average localiza-tion error of this method is only 9.7 mm,and the localization time is reduced by about 11 times compared with the normal one‐level localization method.

关键词： database interpolation rendering

Multifractal filtering method for extraction of ocean eddies from remotely sensed imagery

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Acta Oceanologica Sinica 2006年第5期25卷 27-38页

作者： ge yong DU Yunyan CHENG Qiuming LI Ce State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences ＆ Natural Re-sources Research Chinese Academy of Sciences Beijing 100101 China Department of Earth and Space Science and Engineering York University Toronto M3J 1P3 Canada State Key Laboratory of geo-Processes and Mineral Resources China University of Geosciences Beijing 100083 China

Traditional methods of extracting the ocean wave eddy information from remotely sensed imagery mainly use the edge detection technology such as Canny and Hough operators. However, due to the complexities of ocean eddies and image itself, it is sometimes difficult to successfully detect ocean eddies using these methods. A mnltifractal filtering technology is proposed for extraction of ocean eddies and demonstrated using NASA MODIS, SeaWiFS and NOAA satellite data set in the typical area, such as ocean west boundary current. Results showed that the new method has a superior performance over the traditional methods.

关键词： remotely sensed imagery extraction of ocean eddies multifractal filtering