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Wavelet-based numerical methods and their applications in computational mechanics

Advances in Mechanics 2024年第3期54卷 427-476页

作者： Yang B. wang j. Liu x. Zhou Y. Feng Y. Key Laboratory of Mechanics on Disaster and Environment in Western China The Ministry of Education of China College of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 China

Mechanics research advances towards interdisciplinary research, cross-scale correlations, and extreme environmental impacts. Strong nonlinearity, strong discontinuity, significant multi-physics coupling, multiscale, and complex geometries have become common characteristics in solving various mechanics problems quantitatively. Long-term quantitative research indicates that one of the core ingredients for solving such problems effectively lies in constructing numerical methods that can accurately identify, locate, capture, and separate different scale characteristics especially small-scale local characteristics, under multiscale and nonlinearity circumstances. These numerical methods should also possess the capacity to isolate and decouple the large-scale lower-order approximation from the small-scale higher-order truncation error effectively. The intrinsic multiresolution analysis and time-frequency localization characteristics of wavelet theory, as well as the various selectivity of basis functions, align precisely with the demands of this mathematical feature. Therefore, they can provide fundamental theory and diverse approaches for developing efficient quantitative methods to address various complex mechanics problems. Based on this fact, this paper provides a comprehensive discussion of wavelet theory, focusing on the theoretical framework of biorthogonal multi-resolution analysis and the construction method of frequently used wavelet bases. Furthermore, wavelet approximation of the function defined on a finite domain is presented in detail. The fundamental principles, development, merits, and shortcomings of different wavelet-based numerical methods are systematically elucidated. Several novel wavelet-based methods with outstanding performance developed recently are elaborated especially, and their applications in solving typical mechanics problems are reviewed. Meanwhile, the present paper also points out challenges encountered by the existing wavelet-based num

关键词： computational mechanics multiresolution analysis numerical methods wavelet adaptive algorithms wavelet theory

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SEDIMENTARY, MAGMATIC AND TECTONIC CONSTRAINTS ON THE FORMATION OF THE YULONG SUPPER0-LARGE PORPHYRY COPPER POLYMETAL DEPOSIT, EAST TIBET

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地学前缘 2000年第S1期7卷 433-433页

作者： Tang j. x., wang C. S., Gu x. x., Chen j. P., Huang W. [WT5,5”Bx](Chengdu University of Technology, Chengdu 610059, China)

The Yulong supper\|large copper deposit is situated within the well\|known S\|N striking Yulong copper\|molybdenum ore belt. The ore\|bearing biotite\|monogranitic porphyry was emplaced within clastic rocks (mainly shales and siltstones) of the jiapila Formation (T 3 j ) and carbonate rocks of the Bolila Formation (T 3 b ) of the Upper Triassic. Five mineralization patterns have been recognized in the deposit, i.e., ①veinlet\|disseminated Cu\|Mo ore in the porphyry; ②skarn\|type Cu ore at the contact zone with carbonates (T 3 b ); ③stratiform\|like oxidized Cu ore between T 3 b carbonate rocks and T 3 j hornstones; ④brecciated Cu ore at the local periphery of porphyry; and ⑤vein Pb\|Zn\|Ag ore in the outer contact zone. They constitute a unique integrated polymetal mineralization series of epigenetic intermediate\|acid magmatic hydrothermal *** have shown that the Yulong deposit was the coupling product of sedimentation, magmatism, and tectonism. The Cu\|bearing sandstones in the japila Formation have provided partial ore\|bearing materials for the porphyry mineralization during the Himalayan period. The mineralized porphyry mass was passively emplaced and controlled by a nose\|like anticlinal trap opening to the north. The interlayered fractured zone formed during folding between the jiapila and Bolila Formations acted as favorable host space for stratiform\|like skarn and oxidized ores. A large number of cleavages and fissures developed during folding provided both conduits for the circulation of ore\|forming fluids and host spaces for Pb\|Zn\|Ag ore veins. The veinlet\|disseminated Cu\|Mo ore in the porphyry mass owns the characteristics of typical porphyry copper deposits in the world. The veinlet\|disseminated ore body and the stratiform\|like skarn\|type and/or oxidized ore body, the two main ore bodies in Yulong, are connected with each other and shown as “mushroom\|like" shape, in which the former occurs as “mushroom stem" and the latter as “mushr

关键词： copper polymetal deposit porphyry deposit geological constraints Yulong

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Natural forests exhibit higher organic carbon concentrations and recalcitrant carbon proportions in soil than plantations:a global data synthesis

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journal of Forestry Research 2024年第5期35卷 131-141页

作者： xiuqing Nie Hui wang jian wang Shirong Liu Ecology and Nature Conservation Institute Chinese Academy of ForestryKey Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationNo.2 DongxiaofuHaidian DistrictBeijing 100091People’s Republic of China

Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains *** synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution *** results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural ***-ever,SOC chemical compositions were appreciably more evenly distributed in *** on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under *** tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to *** factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical *** could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.

关键词： Global data synthesis Natural forest Plantations Soil organic carbon Soil organic carbon chemical composition

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Dynamic COVID Zero Strategy triggered a significant increase of chlorine-based disinfectant

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 73-80页

作者： xuhao wang Mai Su Chunyan wang Yi Liu School of Environment Tsinghua UniversityBeijing 100084China

Chlorine-based disinfectants(CBDs)have been widely used to prevent and control the spread of the COVID-19,which may lead to the formation of carcinogenic *** China,strict disinfection strategies by local governments/communities or volunteering by residents have been implemented to meet the Dynamic COVID Zero(DCZ)***,the amount of CBDs used has not been *** author proposed an urban-scale disinfectant consumption estimation(ALICE)model to quantify weekly CBD *** results show that the CBD consumption for the urban region of Beijing during the DCZ strategy was 3704.0 t(0.43 kg/(cap-yr)),equivalent to a monthly increase of 15 g/cap(70.5%)in CBD consumption compared with that in *** to the scenario analysis,a stricter strategy with a shorter response time toward new cases will decrease the total CBD consumption by 1.2% compared with the baseline estimation.A more precise prevention strategy with a smaller delineation of risk area and a less stringent strategy with a longer response time will lower the total CBD consumption by 0.42% and 0.35%,***,the more precise prevention strategy will reduce CBD consumption of close off and lockdown area(COLD area)by 16.9%,and the stricter strategy will reduce this consumption by 37.7%.This study highlights the impact of pandemic prevention and control strategies on chlorine-based disinfectant consumption and some implications for future environmental pollution and risk assessments.

关键词： COVID-19 Dynamic COVID Zero Strategy Disinfectants consumption Bottom-up approach Scenario analysis

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Effect of interplanetary magnetic field B_(x)on the polar electrojets as observed by CHAMP and Swarm satellites

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Earth and Planetary Physics 2024年第2期8卷 382-390页

作者： Hui wang ChengZhi wang YunFang Zhong Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China

Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEjs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEjs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEj when it is0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is0 in the Southern Hemisphere.

关键词： polar electrojet interplanetary magnetic field Bx local time asymmetry hemispheric difference

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Atomistic Investigation of Shock-Induced Amorphization within Micro-shear Bands in Hexagonal Close-Packed Titanium

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng K.G.wang T.Ali D.Li C.G.Bai D.S.xu S.j.Li A.H.Feng G.j.Cao j.H.Yao Q.B.Fan H.wang R.Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing(ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Engineering Tongji UniversityShanghai 201804China Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing 210009China National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The mechanical response of a single crystal titanium sample against(0001)α surface impact was investigated using molecular dynamics ***,non-uniform plastic deformation was observed in the *** high strain rates,amorphization occurred near the edge of the contact region where severe shear strain induced a large number of stacking faults(SFs)and *** contrast,the central part of the contact region underwent less deformation with significantly fewer ***,instead of amorphization by consuming SFs and dislocations,there was a gradual increase in the density of dislocations and SFs during the process of *** local amorphous regions eventually grew into shear bands.

关键词： Shock compression Amorphization Shear band Titanium Molecular dynamics

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Interactive mechanism and friction modelling of transient tribological phenomena in metal forming processes: A review

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Friction 2024年第3期12卷 375-395页

作者： xiao YANG Heli LIU Lemeng ZHANG Yiran HU Denis j.POLITIS Mohammad M.GHARBI Liliang wang Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Department of Mechanical and Manufacturing Engineering University of CyprusNicosia 1678Cyprus Quaker Houghton Deutschland GmbH Dortmund 44319Germany

The accurate representation of tribological boundary conditions at the tool–workpiece interface is crucial for analysis and optimization of formability,material flow,and surface quality of components during metal forming *** has been found that these tribological conditions vary spatially and historically with process parameters and contact *** time-dependent tribological behaviours are also known as transient tribological phenomena,which are widely observed during forming processes and many other manufacturing application ***,constant friction values are usually assigned to represent complex and dynamic interfacial conditions,which would introduce deviations in the relevant *** this paper,transient tribological phenomena and the contemporary understanding of the interaction between friction and wear are reviewed,and it has been found that these phenomena are induced by the transitions of friction mechanisms and highly dependent on complex loading conditions at the *** modelling techniques for transient behaviours for metal forming applications are also *** accurately describe the evolutionary friction values and corresponding wear during forming,the advanced interactive friction modelling has been established for different application scenarios,including lubricated condition,dry sliding condition(metal-on-metal contact),and coated system.

关键词： transient tribological phenomena interactive friction mechanism modelling techniques metal forming

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Evolution mechanism and quantitative characterization of initial micro-cracks in marble under triaxial compression

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 586-595页

作者： Zhiliang wang Songyu LI jianguo wang Ao LI Weixiang wang Chenchen FENG jingjing FU School of Civil Engineering Hefei University of TechnologyHefei230009China School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou221116China

The initial micro-cracks affect the evolution characteristics of macroscopic deformation and failure of rock but are often ignored in theoretical calculation,numerical simulation,and mechanical *** this study,we propose a quantitative analysis model to investigate the effects of initial micro-cracks on the evolution of marble deformation and *** relationship between the micro-crack propagation and the marble failure characteristics was comprehensively studied by combining theoretical analysis with a micro-computed tomography(micro-CT)scanning *** found that with the increase of confining pressure,the matrix elastic modulus of the marble first increased and then tended to be stable,while the micro-cracks increased *** sensitivity ranges of the marble sample matrix elastic modulus and micro-cracks to confining pressure were 0–30 MPa and 30–50 MPa,*** porosity and Poisson’s ratio decreased *** increasing proportion of internal micro-cracks led to an increase in the sample *** samples presented mainly shear failure under triaxial compression,and the failure angle decreased linearly with the increase of confining *** convergence direction of cracks decreased *** quantitative analysis model could accurately portray the relationship between the overall macroscopic deformation and the deviatoric stress of the samples at the compaction and the linear elastic stages,thus deepening the understanding of the stress–strain behavior of rocks.

关键词： Marble Initial micro-cracks Triaxial compression Constitutive relationship Crack evolution

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Ore Geology,H-O-C Isotopes and 40Ar-39Ar Dating of the Wutonggou Iron Deposit,Eastern Tianshan,NW China:Implications for the Source,Timing,and Genesis of Hydrothermal Mineralization in a Sedimentary Iron Deposit

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journal of Earth Science 2024年第4期35卷 1170-1185页

作者： Chun-Long wang Yi-Tian wang State Key Laboratory of Geological Processes and Mineral Resources Collaborative Innovation Center for Exploration of Strategic Mineral ResourcesSchool of Earth ResourcesChina University of GeosciencesWuhan430074China MNR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing100037China

The Wutonggou iron deposit is located in the well-known iron metallogenic belt in the eastern Tianshan,NW China,and has been regarded as a sedimentary iron *** hydrothermal overprinting could play indispensable roles in the formation of high-grade iron ores in sedimentary iron deposits,previous studies mainly focused on sedimentary-related iron mineralization,while the nature and contribution of hydrothermal fluids are poorly ***,an integrated study of ore geology,H-O-C isotopes and^(40)Ar-^(39)Ar dating,is conducted on the Wutonggou deposit,in order to reveal the features,source,and timing of hydrothermal *** studied deposit includes two mining sections namely the jianshan and ***δ^(18)O values of early magnetite from the jianshan section range from+3.0‰to+5.8‰that nearly consistent with classic magmatic magnetite,while increase to 6.3‰-8.0‰in the late *** from the two sections shows comparable H-O isotopic compositions and identical fractionation trends,and is plotted in or periphery to the primary magmatic water *** from the two sections are broadly similar in carbon and oxygen isotopic compositions,and siderite from the Wutonggou section is plotted in the same ***,comparable stable isotopic compositions and evolution trends indicate similar magmatic fluids contributed hydrothermal iron mineralization in the two mining ***,water-rock interactions of varying degrees generated distinct mineralization styles in the jianshan and Wutonggou sections,and caused the isotopic fractionation in late *** extracted from a hydrothermal siderite ore yielded a^(40)Ar-^(39)Ar plateau age of 299.5±2.0 Ma,indicates the timing of hydrothermal iron mineralization is corresponding to the emplacement of vicinity *** together,the hydrothermal mineralization in the Wutonggou iron deposit was the product of remobilization and upgrading of early sedimentary iron ores,a

关键词： iron deposits H-O-C isotopes 40Ar-39Ar dating sedimentary iron deposits Wutonggou iron deposit eastern Tianshan

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Structural characteristics and tectonic division of the Zambezi Delta basin in the offshore East Africa:evidences from gravity and seismic data

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Acta Oceanologica Sinica 2024年第4期43卷 105-118页

作者： Guozhang Fan Wen Li Liangbo Ding Wanyin wang Hongping wang Dingding wang Lin Li Hao wang Chaofeng wang Qingluan wang Ying Zhang Hangzhou Research Institute of Petroleum Geology PetroChinaHangzhou 310023China College of Geological Engineering and Geomatics Chang’an universityXi’an 710054China Key Laboratory of Marine Geology and Environment Chinese Academy of SciencesQingdao 266071China National Engineering Research Center of Offshore Oil and Gas Exploration Beijing 100028China Department of Earth Environment and Resources SciencesUniversity of Naples FedericoⅡNaples 80138Italy

The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration *** to the special geological evolutionary background of the Beira High in the Zambezi Delta basin,it has a low gravity anomaly,and the existing seismic survey lines do not cover the whole basin;therefore,it is difficult to interpret the structural characteristics of the whole basin based solely on gravity or seismic *** on satellite altimetry gravity anomaly data,this study infers the distribution characteristics of faults in the Zambezi Delta basin by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)***,constrained by seismic data,the gravity anomaly at the Moho interface is extracted by using the fast forward method of the double-interface model of the gravity anomaly,and this anomaly is then removed from the Bouguer gravity anomaly to obtain the sedimentary layer gravity *** thickness of the sedimentary strata is obtained by inversing the sedimentary basement depth of the whole ***,uplifts and depressions are divided based on a sedimentary layer thickness of 3 *** research demonstrates that the Zambezi Delta basin mainly features nearly SN-trending and NE-trending faults and that these faults exhibit east-west *** nearly SN-trending strike-slip faults controlled the sedimentary development of the basin,and the NE-trending tensile faults may have acted as migration channels for oil,gas and ***“overcompensation”effect of the Moho interface gravity anomaly on the gravity anomaly of the sedimentary layer is caused by the depression of the Moho interface beneath the Beira High,which results in a low gravity anomaly value for the Beira *** pattern of uplifts and depressions trends NE and has the structural characteristics of east-west blocks.

关键词： Zambezi Delta basin satellite altimetry gravity anomaly Beira High fault division uplift and depression pattern

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