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Measuring the mechanical properties of small body regolith layers using a granular penetrometer

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Astrodynamics 2023年第1期7卷 15-29页

作者： Bin Cheng Erik Asphaug Yang Yu Hexi Baoyin School of Aerospace Engineering Tsinghua UniversityBeijing 100084China Lunar&Planetary laboratory University of ArizonaTucsonAZ 85721USA School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Small bodies in the solar system are known to be covered by a layer of loose unconsolidated soil composed of grains ranging from dusty sands to rugged *** geophysical processes have modified these regolith layers since their ***,the landforms on regolith-blanketed surfaces hold vital clues for reconstructing the geological processes occurring on small ***,the mechanical strength of small body regolith remains unclear,which is an important parameter for understanding its dynamic ***,regolith mechanical properties are key factors for the design and operation of space missions that interact with small body *** granular penetrometer,which is an instrument that facilitates in situ mechanical characterization of surface/subsurface materials,has attracted significant ***,we still do not fully understand the penetration dynamics related to granular regolith,partially because of the experimental difficulties in measuring grain-scale responses under microgravity,particularly on the longer timescales of small body *** this study,we analyzed the slow intrusion ofa locomotor into granular matter through large-scale numerical simulations based on a soft sphere discrete element *** demonstrated that the resistance force of cohesionlessregolith increases abruptly with penetration depth after contact and then transitions to a linear *** scale factor of the steady-state component is roughly proportionalto the internal friction of the granular materials,which allows us to deduce the shearstrength of planetary soils by measuring their force depth *** cohesion is included,due to the brittle behavior of cohesive materials,the resistance profile is characterized by a stationary state at a large penetration *** saturation resistance,which represents the failure threshold of granular materials,increases with the cohesion strength of the *** positive correlation pr

关键词： small body regolith granular penetrometer small body exploration granular dynamics

Petrophysical properties of deep Longmaxi Formation shales in the southern Sichuan Basin, SW China

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Petroleum Exploration and Development 2020年第6期47卷 1183-1193页

作者： XU Zhonghua ZHENG Majia LIU Zhonghua DENG Jixin LI Xizhe GUO Wei LI Jing WANG Nan ZHANG Xiaowei GUO Xiaolong State key laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu 610059China College of Geophysics Chengdu University of TechnologyChengdu 610059China Research Institute of Petroleum Exploration&Development-Northwest(NWGI) PetroChinaLanzhou 730020China School of Geosciences and Technology Southwest Petroleum UniversityChengdu 610500China Research Institute of Well Logging and Remote Sensing PetroChina Research Institute of Petroleum Exploration&DevelopmentBeijing 100083China Sichuan Basin Research Center PetroChina Research Institute of Petroleum Exploration&DevelopmentBeijing 100083China

Deep shale layer in the Lower Silurian Longmaxi Formation,southern Sichuan Basin is the major replacement target of shale gas exploration in ***,the prediction of"sweet-spots"in deep shale gas reservoirs lacks physical basis due to the short of systematic experimental research on the physical properties of the deep *** on petrological,acoustic and hardness measurements,variation law and control factors of dynamic and static elastic properties of the deep shale samples are *** study results show that the deep shale samples are similar to the middle-shallow shale in terms of mineral composition and pore *** characteristics of organic-rich shale samples(TOC>2%)indicate that these shale samples have a framework of microcrystalline quartz grains;the intergranular pores in these shale samples are between rigid quartz grains and have mechanical property of hard *** lean-organic shale samples(TOCsoft pores in mechanical *** difference in microtexture of the deep shale samples results in an asymmetrical inverted V-type change in velocity with quartz content,and the organic-rich shale samples have a smaller variation rate in velocity-porosity and velocity-organic matter *** due to the difference in microtexture,the organic-rich shale and organic-lean shale can be clearly discriminated in the cross plots of P-wave impedance versus Poisson’s ratio as well as elasticity modulus versus Poisson’s *** shale samples with quartz mainly coming from biogenic silica show higher hardness and brittleness,while the shale samples with quartz from terrigenous debris have hardness and brittleness less affected by quartz *** study results can provide a basis for well-logging interpretation and"sweet

关键词： southern Sichuan Basin Silurian deep Longmaxi Formation shale rock physical properties elasticity velocity

A Nonhomogeneous Kinetic Model of Liquid Crystal Polymers and Its Thermodynamic Closure Approximation

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Communications in Computational Physics 2010年第2期7卷 383-402页

作者： Haijun Yu Guanghua Ji Pingwen Zhang LMAM School of Mathematical Sciences and CCSEPeking UniversityBeijing 100871China laboratory of Mathematics and Complex Systems Ministry of Education and School of Mathematical SciencesBeijing Normal UniversityBeijing 100875China

A general nonhomogeneous extension of the Doi’s kinetic theory with trans-lational diffusion and nonlocal potential is proposed to describe the microstructuresand defect dynamics of Liquid Crystal Polymer (LCP) solutions. The long-range elas-ticity of polymer molecules is depicted by a kernel type potential, from which onecan derive the well-known Marrucci-Greco potential with weak spatial distortion as-sumption. Applying quasi-equilibrium closure approximation, we get a second-ordermoment model for isotropic long-range elasticity, and this reduced moment modelmaintains the energy dissipation. Implemented by the invariant-based fitting method,the moment model is a decent tool for numerical simulations of defect dynamics andtexture evolution in LCP solutions. The numerical results of in-plane rotational caseshow that the reduced second-order moment model qualitatively predicts complicatednonhomogeneous director dynamics under moderate nematic potential strength, andthe translational diffusion plays an important role in defect dynamics.

关键词： LCP kinetic theory energy dissipation closure approximation defect dynamics

Editorial for the Special Issue on soft matter for Green Chemical Engineering

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Engineering 2021年第5期7卷 543-543页

作者： David A.Weitz Jian-Feng Chen School of Engineering and Applied Sciences&Department of Physics Harvard UniversityCambridgeMA 02138USA State key laboratory of Organic–Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China

soft matter refers to a class of materials that can be easily deformed,either by small forces or by thermal *** materials generally have both solid-like and liquid-like *** are typically characterized by some elastic coefficient whose value is many orders of magnitude less than most *** unit of an elastic constant is pressure or energy *** energies that characterize materials can vary by a few orders of magnitude,from thermal energies to several electron volts,the latter of which characterize a strong covalent ***,the elastic coefficients of soft materials can be as much as ten orders of magnitude less than those of *** range must reflect a change in the length scale or the density ***,the fundamental physics of soft matter always occurs at larger length scales,and it is the study of these larger length scales that gives the field its great fascination.

关键词： density. energy. orders

Tunable metallic-like transport in polypyrrole

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Materials Futures 2022年第1期1卷 3-8页

作者： Xiaoling Zang Yuqian Jiang Yuqiao Chai Fengwang Li Junhui Ji Mianqi Xue Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijingPeople’s Republic of China laboratory for Nanosystem and Hierarchy Fabrication National Center for Nanoscience and TechnologyBeijingPeople’s Republic of China School of Chemical and Biomolecular Engineering and The University of Sydney Nano Institute The University of SydneySydneyNew South WalesAustralia College of Chemistry and Materials Engineering Beijing Technology and Business UniversityBeijingPeople’s Republic of China Beijing National laboratory for Molecular Sciences BeijingPeople’s Republic of China

Conjugated polymers(CPs),organic macromolecules with a linear backbone of alternating C–C and C=C bonds,possess unique semiconductive properties,providing new opportunities for organic electronics,photonics,information,and energy *** the metallic or metallic-like,even superconducting properties beyond semiconductivity in CPs is always one of the ultimate goals in polymer science and condensed *** two metallic and semi-metallic transport cases—aniline-derived polyaniline and thiophene-derived poly(3,4-ethylenedioxythiophene)—have been reported since the development of CPs for four *** synthesis is a key challenge in discovering more *** we report the metallic-like transport behavior of another CP,polypyrrole(PPy).We observe that the transport behavior of PPy changes from semiconductor to insulator-metal transition,and gradually realizes metallic-like performance when the crystalline degree *** a generalized Einstein relation model,we rationalized the mechanism behind the *** metallic-like transport in PPy demonstrates electron strong correlation and phonon–electron interaction in soft condensation matter,and may find practical applications of CPs in electrics and spintronics.

关键词： conjugated polymers metallic-like polypyrrole transport behavior

材料、能源、机械工程中高效的电流变技术——从机理到应用

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Engineering 2023年第5期24卷 151-171,I0004页

作者： Yudai Liang Dongyang Huang Xuefeng Zhou Ziqiu Wang Quan Shi Yaying Hong Huayan Pu Mengying Zhang Jinbo Wu Weijia Wen Materials Genome Institute Shanghai UniversityShanghai 200444China Zhejiang laboratory Hangzhou 311100China Fok Ying Tung Research Institute The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511458China School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444China Department of Physics Shanghai UniversityShanghai 200444China Department of Physics The Hong Kong University of Science and TechnologyHong Kong 999077China The Advanced Material Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511458China

电流变(ER)技术是一种基于电流变效应的先进技术。电流变技术中最常见的材料是电流变液(ERF)。电流变液是一种软物质智能材料,其黏度可以通过施加电场来可逆地调节。电流变液的衍生物、一种新型的电响应软物质材料——电流变弹性体(ERE)... 详细信息

电流变(ER)技术是一种基于电流变效应的先进技术。电流变技术中最常见的材料是电流变液(ERF)。电流变液是一种软物质智能材料,其黏度可以通过施加电场来可逆地调节。电流变液的衍生物、一种新型的电响应软物质材料——电流变弹性体(ERE),由于其不沉降、易封装的优点也得到了越来越多的关注。电流变材料由于其可逆可调、快速响应、低能耗等特性在机械工程中有着广泛的应用。除了基础的电流变材料的合成和应用以外,电流变技术还应用在了能源材料制备、石油运输、储能等诸多领域。电流变技术在能源领域的应用为其在其他领域的潜在应用提供了一个很好的范例。本文结合最新的研究成果,从机理到应用,系统地综述了电流变技术在材料、能源和机械工程等领域的研究现状和未来发展前景。

关键词：电流变技术电流变弹性体电流变材料机械工程石油运输电流变液电流变效应智能材料