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Thermal performance of cast-in-place piles with artificial ground freezing in permafrost regions

Journal of Mountain Science 2024年第4期21卷 1307-1328页

作者： WANG Xinbin CHEN Kun YU Qihao guo Lei YOU Yanhui jin Mingyang State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

During the construction of cast-in-place piles in warm permafrost,the heat carried by concrete and the cement hydration reaction can cause strong thermal disturbance to the surrounding *** the bearing capacity of the pile is quite small before the full freeze-back,the quick refreezing of the native soils surrounding the cast-in-place pile has become the focus of the infrastructure construction in *** solve this problem,this paper innovatively puts forward the application of the artificial ground freezing(AGF)method at the end of the curing period of cast-in-place piles in permafrost.A field test on the AGF was conducted at the Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment(34°51.2'N,92°56.4'E)in the Qinghai Tibet Plateau(QTP),and then a 3-D numerical model was established to investigate the thermal performance of piles using AGF under different engineering ***,the long-term thermal performance of piles after the completion of AGF under different conditions was *** experiment results demonstrate that AGF is an effective method to reduce the refreezing time of the soil surrounding the piles constructed in permafrost terrain,with the ability to reduce the pile-soil interface temperatures to below the natural ground temperature within 3 *** results further prove that AGF still has a good cooling effect even under unfavorable engineering conditions such as high pouring temperature,large pile diameter,and large pile ***,the application of this method is meaningful to save the subsequent latency time and solve the problem of thermal disturbance in pile construction in *** research results are highly relevant for the spread of AGF technology and the rapid building of pile foundations in permafrost.

关键词： Permafrost engineering Cast-in-place pile Artificial ground freezing Thermal performance.

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Experimental Study on Soot Suppression of Acetylene Diffusion Flame by Acoustic-Excited Oscillation in Rijke-Type Burner

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Journal of Thermal Science 2024年第1期33卷 235-248页

作者： zhu Yibin guo Hui SUO Yan'ge WU Minle YE Yanghui LI guoneng ZHANG Zhiguo School of Mechanical and Energy Engineering Zhejiang University of Science and TechnologyHangzhou 310023China

This work reports that the flame oscillation induced by acoustic excitation can effectively suppress soot generation in Rijke-type *** the acoustic frequency is close to the natural frequency of the burner system,it can produce resonance resulting in intense oscillation of the *** relationship between the soot suppression efficiency and the acoustic field of standing wave at different flame positions is *** with that under self-excited oscillation,when there is external forced acoustic force introduced to the flame,oscillation combustion occurred in a lager zone in the glass *** fundamental cause of different soot suppression efficiency at different positions is that the standing wave acoustic field causes the particles to move at different speeds in different positions of the glass *** axial particle velocity difference results in the formation of acoustic vortexes and the change of the flame *** high particle velocity causes the air in the glass tube to turn into the turbulent condition and make the flame temperature *** results show that the surface growth rate of soot is reduced,while the oxidation rate of soot is enhanced,which result in the soot suppression under acoustic *** study can provide some reference for the practical application of oscillate combustion in soot suppression.

关键词： soot suppression acetylene diffusion flame acoustic-excited oscillation standing wave

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Effect of heat treatment on corrosion behaviors of Mg-6Gd-3Y-0.5Zr alloy

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China Foundry 2024年第5期21卷 599-612页

作者： Fei Wang Bin-guo Fu Yu-feng Wang Tian-shun Dong guo-lu Li jin-hai Liu Hebei Key Laboratory of New Functional Materials School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Tianjin Institute of Aerospace Mechanical and Electrical Equipment Tianjin 300301China Tianjin Aerospace Long March Technology and Equipment Co. Ltd.Tianjin 300462China

The microstructures and corrosion behaviors of as-cast,T4-treated,and T6-treated Mg-6Gd-3Y-0.5Zr alloys were systematically investigated by SEM,TEM,immersion test,and electrochemical corrosion *** results show that the microstructure of the as-cast alloy is composed ofα-Mg and Mg_(24)(Gd,Y)_(5)eutectic phase,and in T4-treated alloy,Mg_(24)(Gd,Y)_(5)phase dissolves into theα-Mg matrix,leading to an increase in the(Y,Gd)H_(2)*** T6 treatment,nanoscale Mg_(24)(Gd,Y)_(5)phase dispersedly precipitates from theα-Mg matrix,and exhibits a specific orientation relationship with theα-Mg:(332)Mg_((24)(Gd,Y)_(5))//(1011)_(α-Mg),[136]Mg_((24)(Gd,Y)_(5))//[1210]_(α-Mg).The corrosion resistance of the Mg-6Gd-3Y-0.5Zr alloys can be ranked in the following order:T6-treated alloy exhibits the highest corrosion resistance,followed by the T4-treated alloy,and finally,the as-cast *** corrosion products of the alloys are all composed of MgO,Mg(OH)_(2),Gd_(2)O_(3),Y_(2)O_(3),and MgCl_(2).The corrosion behavior of Mg-6Gd-3Y-0.5Zr alloy is closely related to the precipitated *** establishing the relationship between corrosion rate,hydrogen evolution rate,and corrosion potential,it is further demonstrated that during the micro galvanic corrosion process,the coarse Mg_(24)(Gd,Y)_(5)phase in the as-cast alloy undergoes extensive dissolution,and(Y,Gd)H_(2)phase promotes the dissolution of theα-Mg matrix in the T4-treated alloy,intensifying the hydrogen evolution *** T6-treated alloy,with dispersive precipitation of nanoscale Mg_(24)(Gd,Y)_(5)phase,exhibits better corrosion resistance performance.

关键词： Mg-6Gd-3Y-0.5Zr alloy heat treatment microstructure precipitated phase corrosion resistance

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Catalytic Reaction Kinetics of Propylene Dimerization to 4-Methyl-1-Pentene Using Cu-K/K_(2)CO_(3) Solid Base Catalyst

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 78-87页

作者： jin Haibo Chai jing Yang Suohe He Guangxiang Ma Lei guo Xiaoyan College of New Materials and Chemical Engineering Beijing Institute of Petrochemical Technology/Beijing Key Laboratory of Fuel Cleaning and Efficient Catalytic Emission Reduction TechnologyBeijing102617China

The catalysis technology of propylene dimerization to form 4-methyl-1-pentene(4MP1)using a Cu-K/K_(2)CO_(3) solid base catalyst is a well-known heterogeneous catalytic *** this study,the intrinsic kinetics of propylene dimerization were studied in a fixed-bed continuous *** and external diffusion during the dimerization reaction experiments were eliminated by adjusting the flow rate of the carrier gas and the particle size of the catalyst ***,the concentration changes of each substance at the outlet of the catalyst bed under different residence times were ***,the suitable reaction kinetics equations was derived using the Langmuir Hinshelwood-Hougen-Watson kinetic ***,the activation energy for each reaction involved in the dimerization reaction was *** activation energies of 4MP1,branched by-products,and 1-hexene were 115.0,150.8,and 177.4 kJ/mol,*** effect of process conditions on propylene dimerization with solid base catalysts was studied through kinetic model *** comparing the theoretical values obtained from the simulation with the experimental results,the applicability and accuracy of the kinetic model were verified.

关键词： propylene dimerization 4-methyl-1-pentene intrinsic kinetics surface reaction

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MXene-based all-solid flexible electrochromic microsupercapacitor

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Microsystems & Nanoengineering 2024年第3期10卷 347-355页

作者： Shanlu guo Ruihe zhu jingwei Chen Weilin Liu Yuxiang Zhang Jianmin Li Haizeng Li College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Optics and Thermal Radiation Research Center Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237China Shenzhen Research Institute of Shandong University Shenzhen 518000China State Key Laboratory of Featured Metal Materials and Life Cycle Safety for Composite Structures Guangxi UniversityNanning 530004China

With the increasing demand for multifunctional optoelectronic devices,flexible electrochromic energy storage devices are being widely recognized as promising platforms for diverse ***,simultaneously achieving high capacitance,fast color switching and large optical modulation range is very *** this study,the MXenebased flexible in-plane microsupercapacitor was fabricated via a mask-assisted spray coating *** adding electrochromic ethyl viologen dibromide(EVB)into the electrolyte,the device showed a reversible color change during the charge/discharge *** to the high electronic conductivity of the MXene flakes and the fast response kinetics of EVB,the device exhibited a fast coloration/bleaching time of 2.6 s/2.5 s,a large optical contrast of 60%,and exceptional coloration *** addition,EVB acted as a redox additive to reinforce the energy storage performance;as a result,the working voltage window of the Ti_(3)C_(2)-based symmetric aqueous microsupercapacitor was extended to 1 ***,the device had a high areal capacitance of 12.5 mF cm^(−2)with superior flexibility and mechanical stability and showed almost 100%capacitance retention after 100 bending *** as-prepared device has significant potential for a wide range of applications in flexible and wearable electronics,particularly in the fields of camouflage,anticounterfeiting,and displays.

关键词： capacitance kinetics exceptional

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Effects of air damping on quality factors of different probes in tapping mode atomic force microscopy

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Chinese Physics B 2024年第9期33卷 506-519页

作者： Yu Zeng guo-Lin Liu jin-Hao Liu Zheng Wei School of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China

The AFM probe in tapping mode is a continuous process of energy dissipation,from moving away from to intermittent contact with the sample *** present,studies regarding the energy dissipation mechanism of this continuous process have only been reported sporadically,and there are no systematic explanations or experimental verifications of the energy dissipation mechanism in each stage of the continuous *** quality factors can be used to characterize the energy dissipation in TM-AFM *** this study,the vibration model of the microcantilever beam was established,coupling the vibration and damping effects of the microcantilever *** quality factor of the vibrating microcantilever beam under damping was derived,and the air viscous damping when the probe is away from the sample and the air squeeze film damping when the probe is close to the sample were *** addition,the mechanism of the damping effects of different shapes of probes at different tip–sample distances was *** accuracy of the theoretical simplified model was verified using both experimental and simulation methods.A clearer understanding of the kinetic characteristics and damping mechanism of the TM-AFM was achieved by examining the air damping dissipation mechanism of AFM probes in the tapping mode,which was very important for improving both the quality factor and the imaging quality of the TM-AFM *** study’s research findings also provided theoretical references and experimental methods for the future study of the energy dissipation mechanism of micro-nano-electromechanical systems.

关键词： TM-AFM quality factors air viscous damping air squeeze film damping

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Humanoid robot heads for human-robot interaction:A review

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Science China(Technological Sciences) 2024年第2期67卷 357-379页

作者： LI Yi zhu LiXiang ZHANG ZiQian guo MingFei LI ZhiXin LI YanBiao HASHIMOTO Minoru Key Laboratory of Special Purpose Equipment and Advanced Processing Technology of Ministry of Education Zhejiang University of TechnologyHangzhou 310023China Zhejiang Provincial Key Laboratoryof Special Purpose Equipment and Advanced Processing Technology Zhejang Universityof Technology Hangzhou 310023 China Faculy of Textile Science and Technology Shinshu UniversityUeda 386-8567Japan

The humanoid robot head plays an important role in the emotional expression of human-robot interaction(HRI).They are emerging in industrial manufacturing,business reception,entertainment,teaching assistance,and tour *** recent years,significant progress has been made in the field of humanoid ***,there is still a lack of humanoid robots that can interact with humans naturally and *** review comprises a comprehensive survey of state-of-the-art technologies for humanoid robot heads over the last three decades,which covers the aspects of mechanical structures,actuators and sensors,anthropomorphic behavior control,emotional expression,and human-robot ***,the current challenges and possible future directions are discussed.

关键词： humanoid robot head anthropomorphic behaviors emotional expression human-robot interaction

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Review of Electrical and Electronic Architectures for Autonomous Vehicles:Topologies,Networking and Simulators

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Automotive Innovation 2024年第1期7卷 82-101页

作者： Wenwei Wang Kaidi guo Wanke Cao Hailong zhu jinrui Nan Lei Yu National Engineering Research Center of Electric Vehicles Beijing Institute of Technology(BIT)Beijing 100081China Shenzhen Automotive Research Institute Beijing Institute of Technology(BIT)Shenzhen 518000China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationBeijing 100876China Purple Mountain Laboratories Nanjing 211111China Beijing Kawen New Energy Vehicle Co. LTDBeijing 102209China

With the rapid development of autonomous vehicles,more and more functions and computing requirements have led to the continuous centralization in the topology of electrical and electronic(E/E)*** certain Tier1 suppliers,such as BOSCH,have previously proposed a serial roadmap for E/E architecture development,implemented since 2015 with significant contributions to the automotive industry,lingering misconceptions and queries persist in actual engineering ***,there are concerns regarding the perspective of zone-oriented E/E architectures,characterized by zonal concentration,as successors to domain-oriented E/E architectures,known for functional *** these misconceptions and queries,this study introduces a novel parallel roadmap for E/E architecture development,concurrently evaluating domain-oriented and zone-oriented ***,the study explores hybrid E/E architectures,amalgamating features from both *** align with the evolution of E/E architectures,networking technologies must adapt *** networking mechanisms pivotal in E/E architecture design are comprehensively ***,the study delves into modeling and verification tools pertinent to E/E architecture *** conclusion,the paper outlines existing challenges and unresolved queries in this domain.

关键词： Autonomous vehicles Electrical and electronic architectures Topology Networking Domain-oriented Zone-oriented

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Enhanced electrical and mechanical properties of Bi_(2)Te_(3)-based thermoelectric thick films enabled by a practical dynamic regulation strategy

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Journal of Materiomics 2024年第2期10卷 480-489页

作者： Jie Zhou Wei zhu Qingqing Zhang Guangyu Han YuTong Liu Zhanpeng guo Siming guo Yue Huang Yuan Deng School of Materials Science and Engineering Beihang UniversityBeijing 100191China Research Institute for Frontier Science Beihang UniversityBeijing 100191China Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province Hangzhou Innovation Institute of Beihang UniversityHangzhou310051China

The application of high-density and high-performance micro thermoelectric devices is still in its infancy,mainly restricted by the low performance of Bi_(2)Te_(3)-based thick film as well as the limited device *** this study,we proposed a dynamic regulation strategy to simultaneously strengthen the thermoelectric and mechanical properties for n-type Bi_(2)Te_(3)-based thick *** effects of growth temperature and time on thermoelectric properties have been firstly *** the thermoelectric properties exhibit consistent degradation with increasing thickness at static growth temperature,an effective rising temperature method is introduced to dynamically regulate the nucleation rate and growing diffusion ***,the grain refinement with compact texture structure leads to a relatively large carrier mobility(77.1 cm^(2)·V^(-1)·s^(-1))and appropriate concentration(5.25×10^(19)cm^(-3))as well as further 12%improvement of power factor with an average value up to 12.0 mW·cm^(-1)·K^(-2)over a wide temperature ranging from 313 K to 453 ***,significant enhancement of mechanical property is also achieved with high elastic modules(56.03 GPa),hardness(0.63 GPa)and large energy dissipation capacity to prevent *** study provides a practical solution with dynamic temperature control to fabricate high-performance Bi_(2)Te_(3) thick films with enhanced mechanical property and pro-cessing feasibility for micro thermoelectric devices.

关键词： Bi_(2)Te_(3)material Thick film Magnetron sputter Dynamic temperature Thermoelectric property Mechanical property

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Pulsations of Three Rapidly Oscillating Ap Stars TIC 96315731,TIC72392575,and TIC 318007796

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Research in Astronomy and Astrophysics 2024年第8期24卷 157-168页

作者： Hai-Jian Zhong Dong-Xiang Shen Chun-Hua zhu He-Lei Liu Su-Fen guo guo-Liang Lü School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China Xinjiang Astronomical Observatory National Astronomical ObservatoriesChinese Academy of SciencesUrumqi 830000China

We analyze the frequencies of three known roAp stars,TIC 96315731,TIC 72392575,and TIC 318007796,using the light curves from the Transiting Exoplanet Survey *** TIC 96315731,the rotational and pulsational frequencies are 0.1498360 day^(-1)and 165.2609 day^(-1),*** the case of TIC 72392575,the rotational frequency is 0.25551 day^(-1).We detect a quintuplet of pulsation frequencies with a center frequency of135.9233 day^(-1),along with two signals within the second pair of rotational sidelobes of the quintuplet separated by the rotation *** two signals may correspond to the frequencies of a dipole *** TIC318007796,the rotational and pulsational frequencies are 0.2475021 day^(-1),192.73995 day^(-1),and196.33065 day^(-1),*** on the oblique pulsator model,we calculate the rotation inclination(i)and magnetic obliquity angle(b)for the stars,which provide the geometry of the pulsation *** the phases of the frequency quintuplets,the pulsation amplitude and phase modulation curves,and the results of spherical harmonic decomposition,we conclude that the pulsation modes of frequency quintuplets in TIC96315731,TIC 72392575,and TIC 318007796 correspond to distorted dipole mode,distorted quadrupole mode,and distorted dipole mode,respectively.

关键词： asteroseismology-techniques photometric-stars oscillations(including pulsations)-stars chemically peculiar

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