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Formulation and procedure for in situ stress back-analysis from borehole strain changes measured during nearby underground excavation

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第8期15卷 1931-1943页

作者： Cui Lin d.h.steve zou Mineral Resource Engineering Dalhousie UniversityHalifaxCanada

Estimation of in situ stresses based on back-analysis of measured stress changes and displacements has become an alternative to the direct stress measurement *** order to help users conduct own measurement and analysis,this paper presents in detail a field stress back-analysis approach directly from borehole strain changes measured during nearby underground *** formulations in major steps and the procedure for the entire analysis process are provided to allow users to *** instrument for borehole strain change measurement can be the CSIR or CSIRO stress cells and other borehole strain cells that can measure strains on borehole *** changes corresponding to the stress changes at a borehole location are calculated in borehole *** stress changes due to nearby excavation can be calculated by an analytical model for a single circular opening and simulated by a numerical model for non-circular and multiple *** models are based on isotropic,homogeneous and linear elastic *** analysis of borehole strain changes is accomplished by multiple linear regression based on error minimization and an integrated process provides the best-fit solution directly to the in situ stresses.A statistical technique is adopted for screening outliers in the measurement data,checking measurement compatibility and evaluating the reliability of analysis *** application example is included to demonstrate the practical application and the analysis procedure.

关键词： In situ stress field Back-analysis Borehole strain change Multiple linear regression Underground excavation data compatibility Result reliability

Analysis of Bingham fluid radial flow in smooth fractures

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第5期12卷 1112-1118页

作者： Liangchao zou Ulf håkansson Vladimir Cvetkovic division of Resources Energy and InfrastructureDepartment of Sustainable DevelopmentEnvironmental Science and EngineeringRoyal Institute of TechnologyStockholm10044Sweden division of Soil and Rock Mechanics Department of Civil and Architectural EngineeringRoyal Institute of TechnologyStockholm10044Sweden Skanska Sweden AB Stockholm11274Sweden

Solutions for radial flow of a Bingham fluid are analyzed in this *** aims to eliminate confusions in the literature concerning the plug flow region in different solutions for analysis and design of grouting in rock *** analyses based on the force balance equation reveal that the plug flow region in Bingham radial flow is independent of the fracture radius,and is not a growth function adapted from the solution of one-dimensional(1d)slit flow according to‘similarity’.Based on the shear stress distribution,we analytically proposed that a non-uniform plug flow region cannot *** Bingham fluid(grout)penetration and flowrate evolution as functions of grouting time are given using the correct expression for the plug flow *** radius-independent plug flow region and the presented flowrate evolution equation are also verified *** radial flow,the relative penetration length is equal to the relative wid.h.of plug flow region,which is the same as that for 1d channel *** in analytical solutions for grout penetration and flowrate evolution were also *** clarification of the plug flow region and evaluation of discrepancies in analytical solutions presented in this work could simplify modeling and design of grouting in rock engineering applications.

关键词： Rock grouting Radial flow of Bingham fluids Plug flow region Force balance Energy dissipation Analytical solution

destruction of the lower crust beneath the North China Craton recorded by granulite and pyroxenite xenoliths

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Science China Earth Sciences 2023年第2期66卷 190-204页

作者： dongya zou hongfu ZhANG School of Earth Sciences Zhejiang UniversityHangzhou310027China department of Geology Northwest UniversityXi’an710069China

The lower crust beneath the North China Craton(NCC)was transformed during the craton destruction in the Mesozoic,however,the transformation processes are yet to be fully *** and geochronological variations of granulite and pyroxenite xenoliths provided insights into the nature of the lower crust before and after the craton *** this study,we summarized the latest results of geochemistry and zircon geochronology coupled with hf-O isotopes from granulite and pyroxenite xenoliths hosted by Phanerozoic igneous rocks in *** previous studies on the granulite terranes and adakitic rocks of NCC,we aim to discuss the destruction processes of lower crust beneath the *** granulite and pyroxenite xenoliths of NCC were divided into two and three groups,respectively,based on the differences of geochemical *** I granulite xenoliths from the NCC have silicic-basic compositions,with metamorphic *** Group I granulite xenoliths show relatively lower Mg#values of pyroxenes and whole-rock than that of the Group II granulite xenoliths,and enrichments of light rare earth elements and Sr-Nd isotopic *** zircons display Archean-Phanerozoic ages with three peaks of Neoarchean,Paleoproterozoic,and ***,Group I granulite xenoliths show close affinities to the granulite terranes of the NCC in terms of the major and trace elements and Sr-Nd isotopic compositions,with a consistent Archean-Proterozoic evolutionary ***,Group I granulite xenoliths have abundant Phanerozoic zircons with variable hf isotopic compositions from depleted to enriched,which could be formed by modifications of magma ***,Group I granulite xenoliths represent the modified ancient lower crust beneath the *** Group II granulite and Group III pyroxenite xenoliths from the NCC have similar geochemical features and are basic in compositions,with metamorphic to magmatic *** Group II gran

关键词： North China Craton destruction of lower crust Granulite xenolith Pyroxenite xenolith

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Rapid Growth of TiNi intermetallic compound within undercooled Ti_(50)Ni_(50)alloy under electrostatic levitation condition

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Journal of Materials Science & Technology 2021年第18期77卷 82-89页

作者： P.F.zou C.h.Zheng L.hu h.P.Wang School of Physical Science and Technology Northwestern Polytechnical University.Xi'an710072China

The undercooling dependence of the solidification mechanism was systematically explored by the electrostatic levitation(ESL)*** the experiments,the maximum undercooling reached up to 406 K(0.26 T_L)and the growth velocity of the primary TiNi phase was in-situ determined at various *** the initial increase of alloy undercooling,the value of growth velocity sluggishly rose followed by a power *** this case,the primary TiNi phase preferentially developed as the equiaxed dendrite,then the remnant liquid participated as Ti_(2)Ni andα-Ti phases on the grain *** the undercooling exceeded the critical value of 350 K,the growth velocity of the primary phase displayed a sharply increase ***,the TEM results demonstrated that the precipitation of the intermetallic Ti_(2)Ni compound was gradually restrained during the rapid solidification and the R-phase existing in the TiNi matrix at large undercooling implied that the martensitic transformation was incomplete.

关键词： Undercooling Ti-Ni alloy Solidification Growth kinetics

Reply to discussion on “Analysis of Bingham fluid radial flow in smooth fractures”

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第4期13卷 945-946页

Recently,hoang et al.(2021)discussed our paper zou et al.(2020).In our paper,we made a statement that dai and Bird(1981)’s solution for two-dimensional(2 d)radial Bingham fluid flow between parallel plates violates mass *** et *** out that dai and Bird(1981)’s solution does not violate the mass balance because dai and Bird(1981)’s solution and our analysis are based on different assumptions,*** consideration of the vertical velocity component in the continuity equation or not,which leads to two different approximation *** this sense,the mass balance of dai and Bird(1981)’s solution should not be checked using our solution as a *** this reply,we add remarks on the two approximation models and their implication for rock grouting *** discussion by hoang et *** this reply are helpful to thoroughly eliminate the existing confusion regarding the two solutions in the rock grouting research community.

关键词： Rock grouting Radial flow Bingham fluid Approximation solution

Simultaneously Enhanced Mechanical Properties and damping Capacities of ZK60 Mg Alloys Processed by Multi-directional Forging

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Acta Metallurgica Sinica(English Letters) 2021年第2期34卷 265-277页

作者： L.B.Tong J.h.Chu d.N.zou Q.Sun S.Kamado h.G.Brokmeier M.Y.Zheng School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China School of Materials Science and Engineering.harbin Institute of Technology Harbin 150001China College of Materials Science and Engineering.Jilin University Changchun 130025China department of Mechanical Engineering Nagaoka University of TechnologyNagaoka 940-2188Japan Institute of Materials Science and Engineering Clausthal University of TechnologyAgricolastrasse 638678 Clausthal-Zellerfeld.Germany

In this study,the mechanical properties and damping capacities of cast Mg-5.5 Zn-0.6 Zr(weight percent,ZK60)alloys have been simultaneously improved by a facile multi-directional forging(MdF)processing,and the mechanisms of microstructure evolution and texture modification are systematically *** activation of tension twinning occurs during the initial MdF stage,due to the coarse-grained structure of the as-cast *** increasing MdF passes,the continuous dynamic recrystallization(CdRX)results in a fine equiaxed-grain *** typical non-basal texture is formed in the as-MdFed alloy for 6 passes,with the(0001)planes inclined 60°–70°to forged direction and 10°–20°to transverse direction,respectively.A good balance between the strength(~194.9 MPa)and ductility(~24.9%)has been achieved,which can be ascribed to the grain refinement,non-basal texture and fine precipitate *** damping capacity is remarkably improved after MdF processing,because the severe deformation increases the dislocation density,which effectively enlarges the sweep areas of mobile dislocations.

关键词： Mg alloy Multi-directional forging Microstructure Texture evolution Mechanical properties damping capacity

Amino Compounds in Poultry Litter,Litter-Amended Pasture Soils and Grass Shoots

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Pedosphere 2014年第2期24卷 178-185页

作者： Z.Q.hE Z.N.SENWO h.X.zou I.A.TAZISONG d.A.MARTENS USdA-ARS Southern Regional Research Center department of Biological and Environmental Sciences Alabama A&M University department of Chemical and Biological Engineering the University of Maine USdA-ARS Southwest Watershed Research Center

Amino compounds （ACs）, i.e., amino acids and amino sugars, are the major forms of organic nitrogen （N） in animal manure and soil. To increase our understanding on the effect of long-term poultry litter （PL） application on soil AC pools and turnover, in this study, we determined the contents of 21 ACs in 23 PL samples, i5 soil samples collected from 0-20, 20-40, and 40-60 cm layers of five pasture plots with 0, 5, 10, 15 and 20 years of PL applications, and 5 grass shoot samples grown on these pasture fields. The contents of 21 ACs were simultaneously determined by methanesulfonic acid.h.drolysis/extraction and anion chromatography-pulsed amperometry. PL application increased soil total and individual AC contents with a distribution pattern similar to that of AC in PL. The highest AC-N concentrations were observed in the soils with 10- or 15-year PL applications, inconsistent with the order of annual application rates or eunmlative applied PL amounts. Application of PL increased the AC contents in grass shoots whereby the highest increase of most ACs was with the shoots from the fields that received PL for 5 years. These observations suggested that both freshly applied and residual PL had contributions to the soil AC-N, and that PL application also accelerated AC-N transformation in soil.

关键词： amino acids amino sugars broiler feed soil nitrogen

Guest editorial: Machine Learning in Wireless Networks

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CAAI Transactions on Intelligence Technology 2021年第2期6卷 133-134页

作者： Anil Kumar Budati steve S.h.Ling department of Electronics and Communication Engineering Gokaraju Rangaraju Institute of Engineering and TechnologyHyderabadIndia School of Biomedical Engineering University of Technology SydneySydneyNew South WalesAustralia

This dedicated Special Section on Machine Learning in Wireless Networks aims to provide improved knowledge for state-of-the-art worldwide R&d communities in wireless networks and machine learning(ML)*** aims to do so by calling for novel formulations,innovative techniques,and optimised solutions to highlight the key issues related to these problems in a forum for shared research and ideas.

关键词： Wireless wireless formulation

A comparison study of Ce/La and Ca microalloying on the bio-corrosion behaviors of extruded Mg-Zn alloys

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Journal of Magnesium and Alloys 2020年第4期8卷 1269-1280页

作者： J.h.Chu L.B.Tong Z.h.Jiang d.N.zou Q.J.Wang S.F.Liu h.J.Zhang School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Key Lab of Automobile Materials College of Materials Science and EngineeringJilin UniversityNanling CampusChangchun 130025China

The influences of Ca and Ce/La microalloying on the microstructure evolution and bio-corrosion resistances of extruded Mg-Zn alloys have been systematically investigated in the current *** with single Ca or Ce/La addition,the Ca-Ce/La cooperative microalloying results in an outstanding grain refinement,because the fine secondary phase particles effectively hinder the recrystallized grain *** coarse Ca2Mg6Zn3 phases promote the formation of Ca3(PO4)2 or hydroxyapatite particles during the immersion process and accelerate the dissolution of the corrosion product film,which destroys its integrity and results in the deterioration of anti-corrosive *** Ce/La elements can be dispersed within the conventional Mg7Zn3 phases,which reduce the internal galvanic corrosion between Mg matrix and the secondary phases,leading to an obvious improvement of corrosion ***,the Ca-Ce/La cooperative microalloying achieves a homogenous fine-grained microstructure and improves the protective ability of surface film,which will pave a new avenue for the design of biomedical Mg alloys in the coming future.

关键词： Extruded Mg-Zn alloy Ca and Ce/La microalloying Microstructure evolution Bio-corrosion behaviors