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10篇 您的检索式:作者名="Junwu Bai"
    题名 作者 年代 出处 被引量
1Experimental and analytical studies on multiple tuned mass dampers for seismic protection of porcelain electrical equipment显示文摘Porcelain electrical equipment(PEE),such as current transformers,is critical to power supply systems,but its seismic performance during past earthquakes has not been satisfactory.This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers(MTMD).An MTMD damping device involving three mass units,named a triple tuned mass damper(TTMD),is designed and manufactured.Through shake table tests and finite element analysis,the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified.The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived.MTMD robustness is verified through adjusting TTMD control frequencies.The damping effectiveness of TTMD,when the peak ground acceleration far exceeds the design value,is studied.Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses.TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.Bai Wen Dai Junwu Zhou Huimeng Yang Yongqiang Ning Xiaoqing 2017Earthquake Engineering and Engineering Vibration2017,16,4:8
2Non-limit passive soil pressure on rigid retaining walls显示文摘This paper aims to reveal the depth distribution law of non-limit passive soil pressure on rigid retaining wall that rotates about the top of the wall(rotation around the top(RT) model). Based on Coulomb theory, the disturbance degree theory, as well as the spring-element model, by setting the rotation angle of the wall as the disturbance parameter, we establish both a depth distribution function for sand and a nonlinear depth distribution calculation method for the non-limit passive soil pressure on a rigid retaining wall under the RT model, which is then compared with experiment. The results suggest that under the RT model: the non-limit soil pressure has a nonlinear distribution; the backfill disturbance degree and the lateral soil pressure increase with an increase in the wall rotation angle; and, the points where the resultant lateral soil pressure acts on the retaining wall are less than 2/3 of the height of the wall. The soil pressure predicted by the theoretical calculation put forward in this paper are quite similar to those obtained by the model experiment, which verifies the theoretical value, and the engineering guidance provided by the calculations are of significance.Dou Guotao Xia Junwu YU Wenjie Yuan Fang Bai Weigang 2017International Journal of Mining Science and Technology2017,27,3:7
3Sedimentary Evolution and Transgressions of the Western Subei Basin in Eastern China since the Late Pliocene显示文摘Sedimentary sequences in the Subei Basin are complex and have been affected by interactions between the ocean and rivers since the Late Pliocene, including the Yellow River, Huaihe River, and the Yangtze River. This sedimentary evolution, in particular the timing of Pleistocene transgressions, has long been a matter of controversy owing to the lack of precise chronological evidence. The aim of this study is to explore the evolution of the sedimentary environment throughout the past 3.00 Ma in this region on the basis of a comprehensive analysis of particle size and foraminifera and ostracods collected in the TZK9 core from the Subei Basin combined with geochronological studies of magnetostratigraphy, AMS^(14)C and optically stimulated luminescence(OSL). The results show that fluvial facies in the sedimentary environment from 3.00 to 1.01 Ma. There were fluvial facies and reflects six sea-level high stands from 1.01 to 0.25 Ma. The study area was affected by four large-scale transgressions since 0.25 Ma. The four marine sedimentary layers known as DU7(buried at 48–52 m), DU5(buried at 35–41 m), DU3(buried at 16–23 m), and DU1(buried at 2–4 m) are recorded in the MIS7(210–250 ka), MIS5, MIS3, and Holocene, respectively. The magnitude of the DU5 transgression was identical to that of the DU3 transgression, both were larger than the DU7 transgression, and the DU1 transgression was the weakest. The variation of transgression strength reflects the influence of global changes in sea level, tectonic subsidence, shell ridges, and sand dams. In the TZK9 core, we found evidence of seven sea-level high stands from the Early–Middle Pleistocene, and the first one caused by regional rapid subsidence and could be traced back to 0.83-0.84 Ma. The sea-level high stands and the age of the first one recorded above was different from other cores in eastern China, this was caused by the lack of absolute age control and the differences in paleotopography during this period. This study reconstructs sedimentary evolution, determines the transgression and its age, establishes the chronology since the Late Pliocene, and provides a scientific framework for further paleoenvironmental and tectonic studies. The results of this study highlight the important role that local tectonics and global sea level play in the sedimentary evolution and transgressions that have occurred in the western Subei Basin.CHENG Yu LI Xiangqian SHU Junwu BAI Shibiao ZHAO Zengyu ZHANG Xiangyun GUO Gang ZHANG Ping LIN Jingxing 2019Acta Geologica Sinica(English Edition)2019,93,1:7
4Infective viruses produced from full-length complementary DNA of swine vesicular disease viruses HK/70 strain显示文摘The full-length cDNA clone of swine vesicular disease virus HK/70 strain named pSVOK12 was constructed in order to study the antigenicity, replication, maturation and pathogenicity of swine vesicular disease virus. In vitro transcription RNA from pSVOK12 transfected IBRS-2 cells and the re- covered virus RNA were isolated and sequenced, then indirect hemagglutination test, indirect im- munofluorescence assays, eleectron microscope test, 50% tissue culture infecting dose (TCID50) assays and mouse virulence studies were performed to study the antigenicity and virulence of the recovered virus. The result showed that the infectious clones we ob- tained and the virus derived from pSVOK12 had the same biological properties as the parental strain HK/70. The full-length infectious cDNA clone, pSVOK12, will be very useful in studies of the anti- genicity, virulence, pathogenesis, maturation and replication of SVDV.ZHENG Haixue LIU Xiangtao SHANG Youiun WU Jinyan BAI Xingwen JIN Ye SUN Shiqi GUO Huichen TIAN Hong FENG Xia YIN Shuanghui GUO Jianhong CONG Guozheng LIU Zaixin CHANG Huiyun MA Junwu XIE Qingge 2006Chinese Science Bulletin2006,51,17:6
5Duration of hypertension is associated with cognitive function: a cross-sectional study in Chinese adults显示文摘Li Tuo Bai Yu Xiang Junwu Wang Rui Bai Jie Tuo Xiping Zhao Zhongxin 2014Chinese Medical Journal2014,,11:5
6Study of a new-type of steel buckling-restrained brace显示文摘The rectangle core plate of all-steel buckling-restrained braces(BRBs) usually exhibit obvious local buckling, due to the lack of longitudinal restraint from the encasing tube. To eliminate the undesirable effects, a novel steel BRB is proposed. In this new-type steel BRB, two T-shaped steels are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar. Meanwhile, the ingot-iron material with low yielding strength and high elongation is applied to the steel core to study the mechanical properties of steel BRBs. To validate the theoretical requirements for the width-to-thickness ratio of the steel core and the thickness of angle steel, quasi-static tests of eight specimens were conducted. The tests focused on the energy dissipation capacity and failure modes of the proposed steel BRBs. Nonlinear finite element analysis was also carried out to validate the experimental results. Both the aforementioned results imply that appropriately designed steel BRBs can meet the performance requirements for BRB components.Jiang Tao Dai Junwu Yang Yongqiang Liu Yongbin Bai Wen 2020Earthquake Engineering and Engineering Vibration2020,19,1:2
7Numerical simulation on the seismic performance of retrofitted masonry walls based on the combined finite-discrete element method显示文摘Due to the long construction life,improper design methods,brittle material properties and poor construction techniques,most existing masonry structures do not perform well during earthquakes.The retrofitting method using an external steel-meshed mortar layer is widely used to retrofit existing masonry buildings.Assessing the seismic performance of masonry walls reinforced by an external steel-meshed mortar layer reasonably and effectively is a difficult subject in the research field of masonry structures.Based on the combined finite-discrete elements method,the numerical models of retrofitted brick walls with four different masonry mortar strengths by an external mortar layer are established.The shear strength of mortar and the contact between the retrofitted mortar layer and the brick blocks are discussed in detail.The failure patterns and load-displacement curves of the retrofitted brick walls were obtained by applying low cycle reciprocating loads to the numerical model,and the bearing capacity and the failure mechanism of the retrofitted walls were obtained by comparing the failure patterns,ultimate bearing capacity,deformability and other aspects with the tests.This study provides a basis for improving the seismic strengthening design method of masonry structures and helps to better assess the seismic performance of masonry structures after retrofitting.Wu Biye Dai Junwu Jin Huan Bai Wen Chen Bowen 2023Earthquake Engineering and Engineering Vibration2023,22,3:1
8Triaxial elastoplastic damage constitutive model of unreinforced clay brick masonry wall显示文摘Due to differences in the properties of composition materials and construction techniques,unreinforced masonry is characterized by low strength,anisotropy,nonuniformity,and low ductility.In order to accurately simulate the mechanical behavior of unreinforced brick masonry walls under static and dynamic loads,a new elastoplastic damage constitutive model was proposed and the corresponding subroutine was developed based on the concrete material constitutive model.In the proposed constitutive model,the Rankine strength theory and the Drucker-Prager strength theory were used to define the tensile and compressive yield surface function of materials,respectively.Moreover,the stress updating algorithm was modified to consider the tensile plastic permanent deformation of masonry materials.To verify the accuracy of the proposed constitutive model,numerical simulations of the brick masonry under monotonic and cyclic uniaxial tension and compression loads were carried out.Comparisons among the numerical and theoretical and experimental results show that the proposed model can properly reflect the masonry material mechanical properties.Furthermore,the numerical models of four pieces of masonry walls with different mortar strengths were established.Low cyclic loadings were applied and the results show that the proposed constitutive model can properly simulate the wall shear failure characteristics,and the force-displacement hysteretic curves obtained by numerical simulation are in good agreement with the tests.Overall,the proposed elastic-plastic damage constitutive model can simulate the nonlinear behavior of unreinforced brick masonry walls very well,and can be used to predict the structural response of masonry walls.Wu Biye Dai Junwu Bai Wen Yang Yongqiang 2023Earthquake Engineering and Engineering Vibration2023,22,1:0
9Finite element analysis of an all-steel buckling-restrained brace显示文摘Typical all-steel buckling-restrained braces(BRBs)usually exhibit obvious local buckling,which is attributed to the lack of longitudinal restraint to the rectangle core plate.To address this issue,all-steel BRBs are proposed,in which two T-shaped steel plates are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar.In order to investigate the factors that characterize the hysterical responses of this device,different finite element(FE)models are developed for the specific context.The FE models are developed based on nonlinear finite element software,which incorporate continuum(shell or brick)elements,large displacement,and deformation formulations.In these FE models,two different steel constitutive models are adopted to precisely reproduce the cyclic response of the BRB component.Meanwhile,comparisons between the numerical and experimental results are conducted to validate the effectiveness and accuracy of the robust FE model.The agreements between experimental observations and numerical predictions demonstrate that the FE method could be utilized for in depth parametric analysis.Furthermore,BRBs with detailed configurations can provide excellent hysteretic behavior and seismic performance through the optimal design process.Jiang Tao Dai Junwu Yang Yongqiang Bai Wen Pang Hui Liu Rongheng 2022Earthquake Engineering and Engineering Vibration2022,21,4:0
10Digitally programmable organic light‐emitting tetrodes显示文摘Limited to the structure of traditional light‐emitting devices,electronic devices that can directly convert machine language into human visual information without introducing any back‐end circuit are still not easy to achieve.Based on a specially designed three‐phase co‐planar electrode structure,a new type of three‐phase alternating current driven organic light‐emitting device with the integration of emission and control functions,full‐color tunability and simple device structure is demonstrated in this study.We integrate the light‐emitting function of color‐tunable light‐emitting devices and the switching of three triodes in a single three phase organic light‐emitting device.The state control of luminous color and luminance intensity merely requires the introduction of a kind of machine language,that is an easy‐to‐program 6‐bit binary number coded digital signals.The color adjustable area covers 66%of the color triangle of the National Television System Committee.Such simple and easy‐to‐integrate light‐emitting system has great potential applications in the next‐generation man‐machine interface.Junpeng Ji Biao Yang Chaohong Zhang Yulu Cai Jingwei Chen Changbin Zhao Tao Wang Lijie Wu Ming Liu Junwu Bai Jiangfeng Wang Zhongbin Wu Shufen Chen Haifeng Ling Zhongfu An Yonghua Chen Jianpu Wang Wei Huang Hong Meng 2023SmartMat2023,4,2:0
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