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Rupture process of the 2015 Pishan earthquake from joint inversion of InSAR, teleseismic data and GPS

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Science China Earth Sciences 2018年第10期61卷 1467-1481页

作者： Xun wang weimin wang Junmeng ZHAO Zhenxing YAO Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences College of Earth and Planetary Sciences University of Chinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences

An earthquake of Mw6.4 occurred in Pishan County in Xinjiang Province, northwestern Tibetan Plateau, on July 3,2015. The epicenter was located on an active blind thrust system located at the northern margin of the Western Kunlun Mountain Orogenic Belt southwest of the Tarim Basin. We constructed a shovel-shaped fault model based on the layered-crust model with reference to the seismic reflection profile, and obtained the rupture process of the earthquake from the joint inversion of Interferometric Synthetic Aperture Radar(InSAR) measurements, far-field waveform data, and Global Positioning System(GPS) data. The results show that the seismic fault dips southward with a strike of 109°, and the rupture direction was essentially northward. The fault plane rupture distribution is concentrated, with a maximum recorded slip of 73 cm. The main features of the fault are as follows: low inclination angle(25°–10°), thrust slip at a depth of 9–13 km, rupture propagation time of about 12 s, no significant slip in soft or hard sedimentary layers at 0–4 km depth and propagation from the initial rupture point to the surrounding area with no obvious directionality. The InSAR time-series analysis method is used to determine the deformation rate in the source region within 2 years after the earthquake, and the maximum value is ~17 mm yr-1 in the radar line-of-sight direction. Obvious post-earthquake deformation is evident in the hanging wall, with a similar trend to the coseismic displacement field. These results suggest that the Pishan earthquake has not completely released the accumulated energy of the region, given that the multilayer fold structure above the blind fault is still in a process of slow uplift since the earthquake. Post-earthquake adjustment models and aftershock risk analysis require further study using more independent data.

关键词： Pishan earthquake Source process Joint inversion Post-earthquake deformation

Strong earthquake clustering around the eastern Tibetan Plateau after the 2008 MW7.9 Wenchuan earthquake

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Science China Earth Sciences 2020年第7期63卷 999-1012页

作者： Duyuan XU Jie XIAO Jiankun HE weimin wang Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

After the 2008 M_W7.9 Wenchuan earthquake,the eastern Tibetan Plateau experienced a series of M_W>6.0 earthquakes,including the 2013 M_W6.6 Lushan,2014 M_W6.1 Kangding and 2017 M_W6.5 Jiuzhaigou *** on available constraints,we build a three-dimensional viscoelastic finite element model to calculate Coulomb failure stress caused by these strong *** this model,the geometry and slip vector of the initial rupture zone of each earthquake are used to better evaluate the earthquake-related stress *** reasonable ranges of viscosities for the crust and upper mantle in different tectonic units,numerical results show that after the Wenchuan earthquake,the coseismic Coulomb failure stress change at the hypocenters of the subsequent earthquakes increased to approximately+0.012–+0.040,+0.01–+0.03,and+0.008–+0.015 MPa,*** viscoelastic relaxation of the lower crust and upper mantle,the Coulomb failure stress change at the hypocenters of these earthquakes accumulated to about+0.014–+0.042,+0.016–+0.036,and+0.003–+0.007 MPa just before their *** suggests that the Wenchuan earthquake indeed triggered or hastened the occurrence of the Lushan,Kangding and Jiuzhaigou events,supporting that strong earthquake clustering around the eastern Tibetan Plateau could be related to stress interaction between the seismogenic ***,~94%and^6%of the stress increase around(and before the occurrence of)the Kangding earthquake were contributed by the Wenchuan event and the Lushan event,respectively;the positive Coulomb failure stress change at the Jiuzhaigou earthquake hypocenter was related to coseismic slip partitioning of the Wenchuan *** means that stress interaction among the earthquakes could be controlled by the combined effect of stress of the previous events and by the complexity of earthquake ***,in researches on the earthquake-triggering mechanism,special attentions should be paid on both details o

关键词： Earthquake clustering Viscoelastic stress triggering Finite element modeling Wenchuan earthquake Eastern Tibetan Plateau

Experimental Investigation on Vibration Control of Rotor-bearing System with Active Magnetic Exciter

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Chinese Journal of Mechanical Engineering 2011年第6期24卷 1013-1021页

作者： wang weimin GAO Jinji HUANG Liquan XIN Zhengqiu Diagnosis and Self-recovery Engineering Research Center Beijing University of Chemical TechnologyBeijing 100029China

Vibration control is an efficient way to minimize a rotating machine’s vibration level so that its vibration fault-free can be ***,several factors,such as unbalance,misalignment and instability,contribute to the serious vibration of rotating *** is necessary that one apparatus can depress vibration caused by two or more *** fault self-recovery(FSR) mechanism is introduced and *** of vibration control are investigated theoretically using numerical method *** magneticelectric exciter(AME) are selected as the actuator of a FSR device because it can provide suitable force by varying the control current in the exciters depending upon a proportional and derivative control *** numerical study,it is indicate that only a small control force is needed to improve stability margins of the compressor and prevent subsynchronous vibration fault *** synchronous vibration,three control strategies,searching in whole circle,fast optimizing control(FOC),and none mistaking control,are investigated to show which of the control strategy can realize the fault self-recovery in the shortest *** study is conducted on a test rig with variable rotating *** of the test indicate that the non-mistake control strategy can minimize synchronous vibration in less than three *** proposed research can provide a new insight for subsynchronous and synchronous vibration restraining about centrifugal compressor.

关键词： vibration control rotor-bearing system active magnetic exciter subsynchronous

Structural Evolution of Graphene Oxide and Its Thermal Stability During High Temperature Sintering

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Journal of Wuhan University of Technology(Materials Science) 2022年第3期37卷 342-349页

作者： HU Lanxin wang Aiyang wang weimin School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

The thermal reduction of graphene oxide(GO)was performed by a tube furnace at different temperatures,and its structure evolution was investigated in *** results showed that the oxygen-containing functional groups on the carbon plane surface of GO gradually decomposed as the temperature increase,and the reduced graphene oxide(rGO)powder was obtained at 800℃.Then,rGO powder was sintered under 30 MPa at 1800℃using spark plasma sintering(SPS)and hot-pressing(HP)to evaluate its structural stability at high *** defect densities of rGO were reduced after high-temperature *** edge flatness and sp^(2) hybrid carbon plane structure were reconstructed *** results demonstrate that the lamellar structure of rGO maintains the structural integrity during high-temperature sintering without obvious deterioration,which provides experimental and theoretical supports for GO reinforced ceramics.

关键词： graphene oxide ceramics structure evolution thermal stability sintering

Effect of Compression on the Crystallization Behavior and Corrosion Resistance of Al_(86)Ni_9La_5 Amorphous Alloy

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Journal of Materials Science & Technology 2012年第12期28卷 1102-1108页

作者： Yan Liu weimin wang Hongdi Zhang Haitian Ma Bang An Key Laboratory for Liquid-solid Structural Evolution and Processing of Materials Shandong University Jinan 250061 China Department of Materials Science and Engineering Shandong Jianzhu University Jinan 250101 China

The effect of compression on the crystallization behavior and corrosion resistance of Al（86）Ni9La5 amorphous ribbons was investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning elec-tron microscopy （SEM） and electrochemistry test. The XRD and TEM results reveal that the compressed Al（86）Ni9La5 ribbons spun with the circumferential speed （R） of 29.3 m/s are in fully amorphous state; however, the compressed ribbons spun with R=14.7 m/s have crystalline phases embedded in the amorphous matrix. The SEM images indicate that after compression, the toughness of the ribbons increases. Electrochemical results show that the compression decreases the stability of the passive film of the Al（86）Ni9La5 amorphous ribbons, because of the compression-introduced free volume, shear bands and crystalline phases; meanwhile, with R=14.7 m/s, the compression-induced crystalline phases in the Al（86）Ni9La5 ribbons increase the corrosion potential.

关键词： Compression Crystallization Corrosion resistance Quenched-in nuclei

5G Wideband Bandpass Filtering Power Amplifiers Based on a Bandwidth-Extended Bandpass Matching Network

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China Communications 2023年第11期20卷 56-66页

作者： weimin wang Hongmin Zhao Yongle Wu Xiaopan Chen School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China School of Integrated Circuits Beijing University of Posts and TelecommunicationsBeijing 100876China

In this paper,a 5G wideband power amplifier(PA)with bandpass filtering response is synthesized using a bandwidth-extended bandpass filter as the matching network(MN).In this structure,the bandwidth(θ_(C))is defined as a variable in the closedform equations provided by the microstrip bandpass *** can be extended over a wide range only by changing the characteristic impedances of the *** from the other wideband MNs,the extension of bandwidth does not increase the complexity of the structure(order n is fixed).In addition,based on the bandwidth-extended structure,the wideband design of bandpass filtering PA is not limited to the fixed bandwidth of the specific filter *** theoretical analysis of the MN and the design flow of the PA are provided in this *** fabricated bandpass filtering PA can support almost one-octave bandwidth(2-3.8 GHz),covering the two 5G bands(n41 and n78).The drain efficiency of 47%-60%and output power higher than 40 dBm are *** frequency selectivity in S-parameter measurements can be observed.

关键词： bandpass filtering bandwidth-extension fixed order power amplifier wideband

On Dynamic Channel Emulation in Sector MPAC for Over-the-Air Testing of Beamformed Massive MIMO Devices

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China Communications 2023年第4期20卷 41-56页

作者： Xiaochen Chen Heng wang weimin wang Zheng Liu Yuanan Liu China Academy of Information and Communications Technology Beijing 100191China Beijing Key Laboratory of Work Safety Intelligent Monitoring Department of Electronic EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China

In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel *** the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational *** the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading *** standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed *** simulation results show that more competent active probes are selected with the proposed method compared to the conventional ***,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical ***,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active *** satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.

关键词： beamforming channel emulation massive MIMO device multiple probe anechoic chamber(MPAC) over-the-air testing

A novel none once per revolution blade tip timing based blade vibration parameters identification method

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Chinese Journal of Aeronautics 2020年第7期33卷 1953-1968页

作者： weimin wang Xulong ZHANG Dongfang HU Dengpeng ZHANG Paul ALLAIRE Key Lab of Engine Health Monitoring-Control and Networking Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Health Monitoring Control and Fault Self-recovery for High-end Machinery Beijing University of Chemical TechnologyBeijing 100029China Rotor Bearing Solutions International LLCCharlottesvilleVA 22911USA

The vibration caused blade High Cycle Fatigue(HCF)is seriously affects the safety operation of turbomachinery especially for ***,it is crucial important to identify the blade vibration parameters and then evaluate the dynamic stress *** Tip Timing(BTT)method is one of the promising method to solve these ***,it need a high resolution Once Per Revolution(OPR)signal which is difficult to get for the ***,a Coupled Vibration Analysis(CVA)method for identifying blade vibration parameters by a none OPR BTT is *** method assumes that every real blade has its own vibration performance at a given ***,it can take any blade as the reference blade,and the other blades using the reference blade as the OPR for vibration displacement calculating and further parameter *** proposed method is validated by numerical ***,experimental studies are carried out on a straight blade and a twisted three dimensional blade test rig as well as a large industrial axial compressor *** results show that the proposed method can accurately identify the blade synchronous vibration parameters and quantitatively evaluate the mistuning in bladed disks,which lays a foundation for the reliability improvement of aero-engine.

关键词： Blade tip timing Blade vibration Parameter identification Turbomachinery blades Vibration analysis

Creating Distinctive Connections between Multifunctional Microwave Circuits and Mobile-Terminal Radio-Frequency Integrated Chips Using Integrated Passive Device Technology

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China Communications 2021年第8期18卷 121-132页

作者： Yongle Wu Mengdan Kong Zheng Zhuang weimin wang School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

In this review,the advanced microwave devices based on the integrated passive device(IPD)technology are expounded and discussed in detail,involving the performance breakthroughs and circuit ***,the development trend of IPD-based multifunctional microwave circuits is predicted further by analyzing the current research hot *** paper discusses a distinctive research area for microwave circuits and mobile-terminal radio-frequency integrated chips.

关键词： chips integrated passive device(IPD) multifunctional microwave circuit