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Nonlinear analysis of pile load-settlement behavior in layered soil

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journal of central South University 2015年第9期22卷 3615-3623页

作者：吕述晖王奎华张鹏 c.j.LEO Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education (Zhejiang University) cccc Fourth Harbon Engineering Institute co. Ltd. School of computing Engineering and Mathematics University of Western Sydney Locked Bag 1797 Penrith Sydney NSW 2751 Australia

A simplified approach is presented to analyze the single pile settlement in multilayered soil. First, a fictitious soil-pile model is employed to consider the effect of layered soil beneath pile toe on pile settlement behavior. Two approximation methods are proposed to simplify the nonlinear load transfer function and simulate the nonlinear compression of fictitious soil-pile, respectively. On this basis, an efficient program is developed. The procedures for determining the main parameters of mathematical model are discussed. comparisons with two well-documented field experimental pile loading tests are conducted to verify the rationality of the present method. Further studies are also made to evaluate the practicability of the proposed approach when a soft substratum exists, and the results suggest that the proposed method can provide a constructive means for assessing the settlement of a single pile for use in engineering design.

关键词： pile load-settlement behavior fictitious soil-pile layered soil soft substratum sediment

Precipitation on stacking faults in Mg–9.8wt%Sn alloy

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journal of Materials Science & Technology 2020年第10期42卷 230-240页

作者： c.Q.Liu c.He H.W.chen j.F.Nie International joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Department of Materials Science and Engineering Monash UniversityVictoria3800Australia Electron Microscopy center Chongqing UniversityChongqing400044PR China

In this work,we have systematically investigated precipitation ofβ’-Mg3Sn phase on intrinsic stacking faults I1 and I2 in a Mg-9.8 wt%Sn alloy using aberration-corrected scanning transmission electron *** observed I1 faults are generated by the dissociation of c+a perfect dislocations and bounded by Frank partial dislocations having a Shockley *** ofβ’on I1 involves a shear of 1/3α,similar to its formation directly from theα-Mg ***β’phase often nucleates at one end of an I1 fault due to the interaction between shear strain fields ofβ’and the Shockley component of the Frank partial at that end,and subsequently grows towards the other end of the *** theβ’reaches to the other end,the Shockley partial bounding the lengthening end of theβ’reacts with the Frank partial bounding the fault,generating an a perfect dislocation that can glide away from the precipitate and the *** observed I2 faults are generated by the dissociation of a perfect dislocations and bounded by Shockley *** ofβ’on I2 does not need a shear of 1/3α,since the pre-existing I2 fault already provides an ABcA four-layer structure ofβ’.Thickening of theβ’that has already formed on the I2 involves the successive occurrence of three crystallographically equivalent shears of 1/3αon every second(0002)αplane of theα-Mg *** this thickening mechanism is similar to that of theβ’formed directly from theα-Mg matrix,an a perfect dislocation will be produced when theβ’is thickened to eight layers,and it can again glide away from the precipitate and the fault.

关键词： Heterogeneous precipitation HAADF-STEM Shockley partial dislocation Frank partial dislocation Dislocation reaction

conception of tooling adapted to thixoforging of high solid fraction hot-crack-sensitive aluminium alloys

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Transactions of Nonferrous Metals Society of china 2010年第9期20卷 1712-1718页

作者： G.VANEETVELD A.RASSILI j.c.PIERRET j.LEcOMTE-BEcKERS Thixo Unit B56University of Liège Special Metallic Materials B52University of Liège

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.7<φs<1), which involves the processing of alloys in the semi-solid *** has to be adapted to this particular process to benefit shear thi... 详细信息

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.7ch involves the processing of alloys in the semi-solid *** has to be adapted to this particular process to benefit shear thinning and thixotropic behaviour of such semi-solid *** parameters, such as the forming speed and tool temperature, have to be accurately controlled because of their influence on thermal exchanges between material flow and *** thermal exchanges influence the high-cracking tendency and the rheology of the semi-solid material during forming, which affects parts properties and therefore their *** tests show how thermal exchanges influence quality of thixoforged parts made of 7075 aluminium alloys at high solid fraction by modifying process parameters like forming speed, tool temperature and tool thermal *** an optimum in terms of thermal exchanges has to be found between surface quality and mechanical properties of the part.A direct application is the evaluation of surface quality of thixoforged thin wall parts made of 7075 aluminium alloy.

关键词： thixoforging solid fraction near-net-shaping tooling 7075 aluminium alloys

Manifestation of external field effect in time-resolved photo-dissociation dynamics of LiF

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chinese Physics B 2013年第7期22卷 140-147页

作者：孟庆田 A. j. c. Varandas Department of Physics Institute of Physics and ElectronicsShandong Normal University Departamento de Quimica Universidade de Coimbra

The photo-dissociation dynamics of LiF is investigated with newly constructed accurate ab initio potential energy curves （PEcs） using the time-dependent quantum wave packet method. The oscillations and decay of the wave packet on the adiabats as a function of time are given, which can be compared with the femtosecond transition-state （FTS） spectroscopy. The photo-absorption spectra and the kinetic-energy distribution of the dissociation fragments, which can exhibit the vibration-level structure and the dispersion of the wave packet, respectively, are also obtained. The investigation shows a blue shift of the band center for the photo-absorption spectrum and multiple peaks in the kinetic-energy spectrum with increasing laser intensity, which can be attributed to external field effects. By analyzing the oscillations of the wave packet evolving on the upper adiabat, an approximate inversion scheme is devised to roughly deduce its shape.

关键词： photo-dissociation dynamics time-dependent wave packet method photo-absorption spectra external field effect

Effects of adenosine triphosphate concentration on motor force regulation during skeletal muscle contraction

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Acta Mechanica Sinica 2017年第2期33卷 243-249页

作者： j. Wei c. Dong B. chen Department of Engineering Mechanics Zhejiang UniversityHangzhou 310058 China

We employ a mechanical model of sarcomere to quantitatively investigate how adenosine triphosphate (ATP) concentration affects motor force regulation during skeletal muscle contraction. Our simulation indicates that there can be negative cross-bridges resisting contraction within the sarcomere and higher ATP concentration would decrease the resistance force from negative cross-bridges by promoting their timely detachment. It is revealed that the motor force is well regulated only when ATP concentration is above a certain level. These predictions may provide insights into the role of ATP in regulating coordination among multiple motors.

关键词： Motor force regulation ATP Muscle contraction Myosin

How single-cell immunology is benefiting from microfluidic technologies

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Microsystems & Nanoengineering 2020年第1期6卷 728-741页

作者： Fabien c.jammes Sebastian j.Maerkl Institute of Bioengineering School of EngineeringEcole Polytechnique Federale de LausanneLausanneSwitzerland

The immune system is a complex network of specialized cells that work in concert to protect against invading pathogens and tissue *** in this network often result in excessive or absent immune responses leading to allergies,autoimmune diseases,and *** of the mechanisms and their regulation remain poorly *** cells are highly diverse,and an immune response is the result of a large number of molecular and cellular interactions both in time and *** bulk methods are often prone to miss important details by returning population-averaged *** is a need in immunology to measure single cells and to study the dynamic interplay of immune cells with their *** in the fields of microsystems and microengineering gave rise to the field of microfluidics and its application to *** systems enable the precise control of small volumes in the femto-to nanoliter *** controlling device geometries,surface chemistry,and flow behavior,microfluidics can create a precisely defined microenvironment for single-cell studies with spatio-temporal *** features are highly desirable for single-cell analysis and have made microfluidic devices useful tools for studying complex immune *** addition,microfluidic devices can achieve high-throughput measurements,enabling in-depth studies of complex *** has been used in a large panel of biological applications,ranging from single-cell genomics,cell signaling and dynamics to cell–cell interaction and cell migration *** this review,we give an overview of state-of-the-art microfluidic techniques,their application to single-cell immunology,their advantages and drawbacks,and provide an outlook for the future of single-cell technologies in research and medicine.

关键词： fluid network details

Role of inflammation and infection in the pathogenesis of human acute liver failure: clinical implications for monitoring and therapy

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World journal of Gastroenterology 2016年第26期22卷 5958-5970页

作者： Mhairi c Donnelly Peter c Hayes Kenneth j Simpson Department of Hepatology and Scottish Liver Transplant Unit Royal Infirmary of Edinburgh

Acute liver failure is a rare and devastating clinical condition. At present, emergency liver transplantation is the only life-saving therapy in advanced cases, yet the feasibility of transplantation is affected by the presence of systemic inflammation, infection and resultant multiorgan failure. The importance of immune dysregulation and acquisition of infection in the pathogenesis of acute liver failure and its associated complications is now recognised. In this review we discuss current thinking regarding the role of infection and inflammation in the pathogenesis of and outcome in human acute liver failure, the implications for the management of such patients and suggest directions for future research.

关键词： Inflammation Neuroinflammation Acute liver failure Biomarker Infection

Ground control monitoring of retreat room–and–pillar mine in central Appalachia

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International journal of Mining Science and Technology 2017年第1期27卷 65-69页

作者： Erik c.Westman Ryan j.Molka William j.conrad Mining and Minerals Engineering Department Virginia TechBlacksburgVA 24061USA

In order to study pillar and overburden response to retreat mining, a ground control program was conducted at a central Appalachian Mine. The program consisted of several monitoring methods including a seismic monitoring system, borehole pressure cells in the pillars, and time-lapse photogrammetry of the pillar ribs. Two parallel geophone arrays were installed, one on each side of the panel with the sensors mounted 3 m into the roof. A total of fourteen geophones recorded more than 5000 events during the panel retreat. A MIDAS datalogger was used to record pressure from borehole pressure cells(BPcs)located in two adjacent pillars that were not mined during retreat. A series of photographs were taken of the pillars that had the BPcs as the face approached so that deformation of the entire rib could be monitored using photogrammetry. Results showed that pillar stability and cave development were as expected. The BPcs showed an increase in loading when the face was 115 m inby and a clear onset of the forward abutment at 30 m. The photogrammetry results displayed pillar deformation corresponding to the increased loading. The microseismic monitoring results showed the overburden caving inby the face, again as expected. The significance of these results lies in two points,(1) we can quantify the safe manner in which this mine is conducting retreating operations, and(2) we can use volumetric technologies(photogrammetry and microseismic) to monitor entire volumes of the mine in addition to the traditional point-location geotechnical measurements(BPcs).

关键词： Retreat mining Stress measurement Microseismic monitoring Pillar stability

Slumping in the Upper jurassic Baisakhi Formation of the jaisalmer Basin, western India: Sign of synsedimentary tectonics?

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journal of Palaeogeography 2017年第4期6卷 321-332页

作者： Matthias Alberti Dhirendra K.pandey jitendra K.Sharma Narendra K.Swami Alfred Uchman Institut für Geowissenschaften Christian-Albrechts-Universitt zu Kiel Department of Geology University of Rajasthan Earth & Planetary Sciences Group/Palaeontology Manipal Center for Natural Sciences Manipal University Institute of Geological Sciences Jagiellonian University

A spectacularly exposed slump is described from a 120-m-long road cut between the villages of Kanod and Deva in the northeastern jaisalmer Basin of Rajasthan,*** Upper jurassic part of the sediments at the outcrop was formed in a near-shore setting and belongs to the Ludharwa Member of the Baisakhi *** 3-m-thick unit shows a number of asymmetric folds and thrust faults leading to an imbrication of partly lithified sandstone *** deformation structures allow the reconstruction of a movement towards the *** agrees well with the basin configuration that shows a deepening into this *** the determination of a specific trigger mechanism is difficult for soft-sediment deformation structures,an earthquake caused by synsedimentary tectonics in the basin seems to be the most likely explanation.

关键词： Sedimentology Mass movements Slumping Soft-sediment deformation structures jaisalmer Basin jurassic