检索结果-南通市图书馆

Earthquake Engineering and Engineering Vibration 2015年第2期14卷 189-201页

作者： Zhang Ning Gao Yufeng Yang Jie xu changjie Geotechnical Research Institute Hohai University Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Nanjing Hydraulic Research Institute Research Center of Coastal and Urban Geotechnical Engineering Zhejiang University

The earth’s surface irregularities can substantially affect seismic waves and induce amplifi cations of ground motions. This study investigates whether and how the source characteristics affect the site amplifi cation effects. An analytical model of a line source of cylindrical waves impinging on an alluvial valley is proposed to link the source and site. The analytical solution to this problem proves one aspect of the strong effect of source on site amplifi cation, i.e., the wave curvature effect. It is found that the site amplifi cation depends on the source location, especially under conditions of a small source-to-site distance. Whether the displacement is amplifi ed or reduced and the size of the amplifi cation or reduction may be determined by the location of the source. It is suggested that traditional studies of site responses, which usually ignore the source effect, should be further improved by combining the source with site effects.

关键词： site effects source effects wave function expansio

Influence of the penetration of adjacent X-section cast-in-place concrete(XCC)pile on the existing XCC pile in sand

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 557-572页

作者： Peng ZHOU Jianhui xu changjie xu Guangwei CAO Jie CUP xuanming DING School of Civil Engineering and Architecture State Key Laboratory of Performance Monitoring and Protecting of Rail Transit InfrastructureEast China Jiaotong UniversityNanchang330013China Guangdong Key Laboratory of Earthquake Engineering and Application Technology Earthquake Engineering Research&Test CenterGuangzhou UniversityGuangzhou510006China Key Laboratory of New Technology for the Construction of Cities in Mountain Areas College of Civil EngineeringChongqing UniversityChongqing400045China Zijin School of Geology and Mining Fuzhou UniversityFuzhou350116China

A series of small-scale 1g X-section cast-in-place concrete(XCC)pile-penetration model tests were conducted to study the effects of soil density and pile geometry on the lateral responses of an existing pile and the variations in surrounding soil *** results showed that the bending patterns of existing XCC piles varied with penetration *** lateral response of the existing pile was sensitive to the change in relative density and pile *** example,the bending moment of the existing pile increased along with these *** development of the radial stressσ′r/σ′v0 of the soil around an existing pile showed different trends at various depths during the penetration of the adjacent ***,the change in radial stress during the penetration of the XCC pile did not exhibit the“h/R effect”that was observed in the free-field soil,due to the shielding effect of the existing *** peak value of radial stressσ′r_max/σ′v0 decreased exponentially as the radial distance r/R *** attenuation ofσ′r_max/σ′v0 with r/R in the loose sand was faster than in the medium-dense or dense ***σ′r_max/σ′v0 at the same soil location increased with the cross-section geometry parameter.

关键词： X-section cast-in-place concrete(XCC)pile Test Penetration Sand Lateral response Radial stress

Earth Pressure of the Trapdoor Problem Using Three-Dimensional Discrete Element Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2023年第5期135卷 1503-1520页

作者： Qizhi Chen Chulixu Baoping Zou Zhanyou Luo changjie xu xu Long School of Civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou310023China School of Civil and Environmental Engineering Ningbo UniversityNingbo315211China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang330013China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China

Load transformation from the yielding part of the soil to the adjacent part is known as the soil arching effect,which plays an important role in the design of various geotechnical ***’s trapdoor test was an importantmilestone in the development of theories on soil *** research on earth pressure of the trapdoor problem is presented in this paper using the three-dimensional(3D)discrete element method(DEM).Five 3D trapdoor models with different heights are established by 3DDEMsoftware PFC *** variation of earth pressure on the trapdoor with the downward movement of the trapdoor,the distribution of vertical earth pressure along the horizontal direction,the distribution of vertical earth pressure along the vertical direction,the distribution of lateral earth pressure coefficient along the depth direction,the magnitude and direction of contact force chain are studied,*** research results show that the earth pressure on the trapdoor decreases rapidly after the downward movement of the trapdoor,and then reaches the minimum earth *** that,the earth’s pressure will rise slightly,and whether this phenomenon occurs depends on the depth *** the bottom soil,due to the stress transfer caused by the soil arching effect,the ratio of earth pressure in the loose area decreases,while the ratio of earth pressure in the stable area *** the trapdoor moving down,the vertical earth pressure along the depth in the stable zone is basically consistent with the initial state,which shows an approximate linear *** the trapdoor moves down,the distribution of earth pressure along with the depth in the loose area changes,which is far less than the theoretical value of vertical earth pressure of its *** of the compression of the soil on both sides,the lateral earth pressure coefficient of most areas on the central axis of the loose zone is close to the passive earth pressure coefficient ***

关键词： Soil arching effect three dimensional discrete element earth pressure contact force chain

Approximation approach to the SRM based on root decomposition in the simulation of spatially varying ground motions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2013年第3期12卷 363-372页

作者： Wu Yongxin Gao Yufeng Li Dayong xu changjie Ali H Mahfouz Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Institute of Engineering Safety and Disaster Prevention Hohai University Geotechnical Research Institute Hohai University Department of Civil Engineering Shandong University of Science and Technology Research Center of Coastal and Urban Geotechnical Engineering Zhejiang University College of Engineering Jazan University

The spectral representation method （SRM） is widely used to simulate spatially varying ground motions. This study focuses on the approximation approach to the SRM based on root decomposition, which can improve the efficiency of the simulation. The accuracy of the approximation approach may be affected by three factors： matrix for decomposition, distribution of frequency interpolation nodes and elements for interpolation. The influence of these factors on the accuracy of this approach is examined and the following conclusions are drawn. The SRM based on the root decomposition of the lagged coherency matrix exhibits greater accuracy than the SRM based on the root decomposition of the cross spectral matrix. The equal energy distribution of frequency interpolation nodes proposed in this study is more effective than the counter pith with an equal spacing. Elements for interpolation do not have much of an effect on the accuracy, so interpolation of the elements of the decomposed matrix is recommended because it is less complicated from a computational efficiency perspective.

关键词： ground motions simulation spectral representation method spatially varying approximation root decomposition

Water retention behavior and shear strength of artificially cemented granite residual soil subjected to free drying

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第11期16卷 4697-4710页

作者： Xinxin Dong Xiaohua Bao Hongzhi Cui changjie xu Xiangsheng Chen MOE Key Laboratory of Coastal Urban Resilient Infrastructures(Shenzhen University) College of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060China State Key Laboratory of Intelligent Geotechnics and Tunnelling Shenzhen UniversityShenzhen518060China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang330013China

Artificially cemented soils have been widely used as filling materials in highway and railway *** shear strength evolution of filling materials upon moist variation can determine the stability of subgrade and *** study conducted water retention tests,MIP tests,and multi-stage triaxial shear tests on cement-treated granite residual soil(GRS)to determine its water retention curve(WRC)upon free drying,pore structure,and peak shear strength qf,*** water retention behavior and shear strength evolution upon free drying were modeled based on the dual-porosity structure of cement-treated GRS and the effective stress principle,*** show that the drying-WRC is bimodal and higher cement dosage yields a more severe decrease in the water retention capacity within a specific suction *** a given confining pressure,the peak shear strength qf increased with increasing cement dosage or suction value *** peak shear strength qf also solely depends on the suction value in the peak stress *** addition,the cement-treated GRS has a bimodal pore size distribution curve,and its macro-and micro-void ratios remain almost unchanged after free *** bimodal drying-WRC of the cement-treated GRS can be modeled by differentiating the water retention mechanisms in macro-and ***,using the macro-pore degree of saturation as the effective stress parameterχ=S_(rM),the q_(f)–p′_(f)relationship(where p′_(f)is the effective mean pressure at failure)under various suction and stress conditions can be unified,and the q_(f)–s relationships at various net confining pressuresσ_(3),net can be well *** findings can help design subgrade and embankments constructed by artificially cemented GRS and assess their safe operation upon climate change.

关键词： Granite residual soil Cement treatment Dual-porosity Water retention behavior Unsaturated shear strength

Study of the approximate approaches to the POD based spectral representation method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2013年第4期56卷 970-979页

作者： WU YongXin GAO YuFeng LI DaYong xu changjie MAHFOUZ Ali Hasson Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Institute of Engineering Safety and Disaster Prevention Hohai University Geotechnical Research Institute Hohai University Department of Civil Engineering Shandong University of Science and Technology Research Center of Coastal and Urban Geotechnical Engineering Zhejiang University College of Engineering Jazan UniversityJazanSaudi Arabia

The spectral representation method (SRM) is most widely used in simulating the stochastic *** proper orthogonal decomposition (POD) based SRM is an important *** paper investigates the approximate approaches to the POD-based SRM in simulating two typical problems,i.e.,the seismic ground motion and wind velocity fields ***,the accuracy resulting from the power spectral density matrix-based POD method (PSRM) is compared to that of the coherency matrix-based POD method (CPSRM).It is concluded that the CPSRM maintains a much higher accuracy than the *** the CPSRM,the linear interpolation of eigenvectors and third-order polynomial interpolation of eigenvalues can be accepted to attain high accuracy;the linearly distributed interpolation nodes are effective in the ground motions simulation;however,the exponentially distributed interpolation nodes are effective in the wind velocity simulation.

关键词： stochastic field simulation coherency matrix based spectral representation method proper orthogonal decomposition approximation

Negative Poisson’s ratio locally resonant seismic metamaterials vibration isolation barrier

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2024年第8期40卷 239-252页

作者： Haibin Ding Nianyong Huang Muhammad changjie xu Lihong Tonog State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure Nanchang330013China Institute of Geotechnical Engineering School of Civil Engineering and ArchitectureEast China Jiaotong UniversityNanchang330013China Department of Mechanical Manufacturing and Biomedical EngineeringTrinity College DublinDublinD02PN40Ireland Department of Mechanical Engineering University of GalwayUniversity RoadGalwayH91 HX31Ireland

In recent decades,the application of seismic metamaterials to protect civil infrastructures being free of the damage of earthquakes has been attracting extensive ***,the proposed locally resonant seismic metamaterials provide the probability of isolating the low-frequency seismic wave using a small-size isolation ***,in previous studies,the energy absorption properties of locally resonant seismic metamaterials remain one of the least understood aspects of *** from the fascinating energy absorption characteristic of negative Poisson ratio(NPR)metamaterial,we creatively design a new seismic metamaterial structure by assembling the locally resonant seismic metamaterial and NPR metamaterial,to isolate seismic *** sound cone technique combining the transmission spectrum is employed to identify the surface wave from the hybrid *** generation mechanism of frequency bandgap and the isolation effectiveness of the proposed seismic metamaterial are discussed in *** results indicate that the generation of ultra-low and ultra-wide frequency bandgap with the range of 0.65 Hz–18.9 Hz is attributed to the locally resonant and energy absorption of the proposed seismic metamaterial structure and the excellent isolation effect is achieved by transforming the surface wave into the bulk *** frequency bandgap narrows as the distance increases between each *** addition,the mechanical properties of the NPR bearing,such as the Poisson ratio,mass density,and elastic modulus,have remarkable impact on the frequency bandgap,especially on the upper bound *** practical engineering,the NPR bearing with a low Poisson ratio,small mass density,and high elastic modulus is suggested for the design of the NPR locally resonant seismic metamaterial *** domain analysis for the practical seismic wave verifies that the proposed seismic metamaterial has a promising application in isolating ultra-low and ultra-wi

关键词： Seismic metamaterials Locally resonant Negative Poisson ratio(NPR) Seismic waves Frequency bandgap Vibration isolation barrier

MYB41,MYB107,and MYC2 promote ABA-mediated primary fatty alcohol accumulation via activation of AchnFAR in wound suberization in kiwifruit

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Horticulture Research 2020年第1期7卷 1666-1675页

作者： Xiaopeng Wei Linchun Mao Xiaobo Wei Ming Xia changjie xu College of Biosystems Engineering and Food Science Zhejiang Key Laboratory of Agro-Food ProcessingKey Laboratory of Agro-Products Postharvest Handling of Ministry of Agriculture and Rural AffairsZhejiang University310058 HangzhouChina Ningbo Research Institute Zhejiang University315100 NingboChina Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology Zhejiang University310058 HangzhouChina

Wound damage triggers the accumulation of abscisic acid(ABA),which induces the expression of a large number of genes involved in wound suberization in *** acyl-CoA reductase(FAR)catalyzes the generation of primary fatty alcohols by the reduction of fatty acids in suberin ***,the regulatory effects of transcription factors(TFs)on AchnFAR in response to ABA are *** this study,kiwifruit AchnFAR displayed a biological function analogous to that of FAR in transiently overexpressed tobacco(Nicotiana benthamiana)*** positive role of TFs,including AchnMYB41,AchnMYB107,and AchnMYC2,in the regulation of AchnFAR was *** three TFs could individually bind to the AchnFAR promoter to activate gene transcription in yeast one-hybrid and dualluciferase *** overexpression of TFs in tobacco leaves resulted in the upregulation of aliphatic synthesis genes(including FAR)and the increase in aliphatics,including primary alcohols,α,ω-diacids,ω-hydroxyacids,and fatty ***,exogenous ABA treatment elevated TF-mediated AchnFAR expression and the accumulation of primary ***,fluridone,an inhibitor of ABA biosynthesis,suppressed the expression of AchnFAR and TF genes and reduced the formation of primary *** results indicate that AchnMYB41,AchnMYB107,and AchnMYC2 activate AchnFAR transcription to promote ABA-mediated primary alcohol formation in wound suberization in kiwifruit.

关键词： wound mediated elevated

Naringin,neohesperidin and their corresponding dihydrochalcones as bioactive substances:a symphony of bitter–sweet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Quality and Safety 2023年第4期7卷 525-540页

作者： Ruoqi Wang Wenwen You Heng Lin Yunlin Cao changjie xu Kunsong Chen Yilong Liu Xian Li Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology Zhejiang UniversityHangzhouChina Shandong(Linyi)Institute of Modern Agriculture Zhejiang UniversityLinyiChina

Bitter is generally undesirable,although it is an important part of *** substances exhibit diverse health-promoting activities,which is in line with the famous Chinese saying‘a good medicine tastes bitter’.Naringin(NAG)and neohesperidin(NHP),two important flavanones that give bitterness to citrus fruits,show various pharmacological ***,their hydrogenation products,*** dihydrochalcone(NDC)and neohesperidin dihydrochalcone(NHDC),undergo a dramatic taste shift from bitter to intensely sweet,which can be 300 and 1000 times sweeter than sucrose,*** sweeteners not only provide a sweet taste without the burden of increased calorie intake and glycemia,but also may exert multiple *** review summarizes common dietary bitter and sweet compounds with sensory *** conversions induced by structural changes from bitter NAG and NHP to sweet NDC and NHDC are particularly *** addition,the taste-sensing mechanisms,pharmacological characteristics,dietary distribution,synthesis,and food industry applications of these bitter–sweet interchangeable compounds are *** conclusion,the bitter NAG and NHP are promising therapeutic candidates for management of diverse etiologically complex diseases while their corresponding dihydrochalcones NDC and NHDC are promising sweeteners,which might be a blessing for those who need to control sugar intake.

关键词： Naringin neohesperidin bitter compounds sweeteners bioactivities

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

预切缝辅助TBM滚刀破岩贯入荷载演化规律

土木与环境工程学报（中英文） 2025年第1期47卷 63-70页

作者：蒋亚龙徐彭楚璇曾建军徐长节熊扶阳华东交通大学土木建筑学院南昌330013 江西省交通科学研究院有限公司南昌330200

基于全断面隧道掘进机(Tunnel Boring Machine,TBM)滚刀贯入室内模型试验,研究了3种不同破岩模式(完整岩样破岩、同轨迹破岩和异轨迹破岩)在不同围压条件下高强度花岗岩样贯入荷载演化特征,重点揭示贯入荷载-贯入度特征曲线、峰值荷载... 详细信息

基于全断面隧道掘进机(Tunnel Boring Machine,TBM)滚刀贯入室内模型试验,研究了3种不同破岩模式(完整岩样破岩、同轨迹破岩和异轨迹破岩)在不同围压条件下高强度花岗岩样贯入荷载演化特征,重点揭示贯入荷载-贯入度特征曲线、峰值荷载、最大跌落幅值变化规律,获取不同破岩模式在不同围压条件下TBM滚刀受力特性。结果表明:1)高围压组贯入荷载-贯入度特征曲线较低围压组先跌落,跌落幅度较小,但其对应的贯入荷载并非峰值荷载,而低围压组初次跌落荷载为峰值荷载,且跌落幅值较大;2)在中高围压10~15 MPa时,峰值荷载及贯入荷载最大跌落幅值均最小,表明此围压范围较利于TBM的掘进;3)低围压条件下选用异轨迹破岩模式较同轨迹破岩模式能更有效地降低TBM滚刀贯入荷载,但同轨迹破岩模式的岩样发生楔裂破坏,其最大跌落幅值最小,更能减少刀具所受冲击荷载,减少刀具磨损。

关键词：高强度超硬岩全断面隧道掘进机预切缝破岩模式贯入荷载