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Adiabatic shear instability in a titanium alloy:Extreme deformation-induced phase transformation,nanotwinning,and grain refinement

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journal of Materials Science & Technology 2023年第19期150卷 104-113页

作者： X.R.guan Q.Chen S.j.Qu g.j.cao H.Wang A.H.Feng D.L.Chen School of Materials Science and Engineering Tongji UniversityShanghai 201804China Southwest Technology and Engineering Research Institute Chongqing 400039China Shanghai Key Laboratory of D&A for Metal-Functional Materials School of Materials Science&EngineeringTongji UniversityShanghai 201804China Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjing 210009China Interdisciplinary Center for Additive Manufacturing School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 2000093China Department of Mechanical and Industrial Engineering Toronto Metropolitan University(formerly Ryerson University)TorontoON M5B 2K3Canada

Increasingly harsh service conditions place higher requirements for the high strain-rate performance of titanium *** shear band(ASB),a phenomenon prone to dynamic loading,is often accom-panied by catastrophic ***,it is unclear how the internal nanostructures are related to shear *** we report detailed microstructural evolution in the ASB of a titanium alloy via in-depth focused ion beam(FIB),transmission Kikuchi diffraction(TKD),and high-resolution transmission electron microscope(HRTEM)analyses,with the deformation instability phenomenon discussed from the energy *** ASB interior undergoes multifaceted changes,namely deformation-induced beta-to-alpha transformation and deformation-induced martensitic transformation to form substantially refined and heterogeneous ***,two types of extremely fine twins are identified to occur within both nano-sized martensite and alpha *** critical plastic work representing the onset of adiabatic shear instability and dynamic equilibrium is observed to be constant for a specific structure in the same deformation *** energy analysis could be extended to other materials subjected to high strain-rate dynamic deformation.

关键词： Adiabatic shear instability Deformation-induced phase transformation Deformation-induced nanotwinning Dynamic recovery Energy analysis

Applications of genetic code expansion technology in eukaryotes

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Protein & Cell 2024年第5期15卷 331-363页

作者： Qiao-ru guo Yu j.cao State Key Laboratory of Chemical Oncogenomic Guangdong Provincial Key Laboratory of Chemical GenomicsPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China

Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to *** eukaryotes,genetic code expansion(gCE)enables the incorporation of UAAs and facilitates posttranscriptional modification(PTM),which is not feasible in prokaryotic *** is also a powerful tool for cell or animal imaging,the monitoring of protein interactions in target cells,drug development,and switch ***,there is keen interest in utilizing gCE in eukaryotic *** review provides an overview of the application of gCE in eukaryotic systems and discusses current challenges that need to be addressed.

关键词： genetic code expansion unnatural amino acid eukaryotes basic research therapeutic applications

Interfacial stress engineering toward enhancement of ferroelectricity in Al doped HfO_(2)thin films

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Chinese Physics B 2024年第9期33卷 637-643页

作者： S X Chen M M Chen Y Liu D W cao g j Chen Department of Microelectronics Jiangsu UniversityZhenjiang 212013China Department of Physics Jiangsu UniversityZhenjiang 212013China guangdong–Hong Kong–Macao joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology Foshan UniversityFoshan 528225China

Ferroelectric HfO_(2)has attracted much attention owing to its superior ferroelectricity at an ultra-thin thickness and good compatibility with Si-based complementary metal-oxide-semiconductor(CMOS)***,the crystallization of polar orthorhombic phase(o-phase)HfO_(2)is less competitive,which greatly limits the ferroelectricity of the as-obtained ferroelectric HfO_(2)thin ***,the crystallization of o-phase HfO_(2)can be thermodynamically modulated via interfacial stress *** this paper,the growth of improved ferroelectric Al doped HfO_(2)(HfO_(2):Al)thin films on(111)-oriented Si substrate has been *** analysis has suggested that nonpolar monoclinic HfO_(2):Al grown on(111)-oriented Si substrate suffered from a strong compressive strain,which promoted the crystallization of(111)-oriented o-phase HfO_(2)in the as-grown HfO_(2):Al thin *** addition,the in-plane lattice of(111)-oriented Si substrate matches well with that of(111)-oriented o-phase HfO_(2),which further thermally stabilizes the o-phase HfO_(2).Accordingly,an improved ferroelectricity with a remnant polarization(2P_(r))of 26.7C/cm^(2) has been *** results shown in this work provide a simple way toward the preparation of improved ferroelectric HfO_(2)thin films.

关键词： improved ferroelectricity interfacial stress engineering compressive strain HfO_(2)

Zeros of Complete Symmetric Polynomials over Finite Fields

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journal of Systems Science & Complexity 2024年第4期37卷 1772-1788页

作者： cao Wei School of Mathematics and Statistics Minnan Normal UniversityZhangzhou 363000China

Wan and Zhang(2021) obtained a nontrivial lower bound for the number of zeros of complete symmetric polynomials over finite fields,and proposed a problem whether their bound can be *** this paper,the author improves Wan-Zhang's bound from three *** proposed results are based on the estimates related to the number of certain permutations and the value sets of non-permutation polynomials associated to the complete symmetric *** the author believes that there are still possibilities to improve the bounds and hence Wan-Zhang's bound.

关键词： Complete symmetric polynomial finite field permutation polynomial value set

Bioinspired Closed-loop CPg-based Control of a Robotic Manta for Autonomous Swimming

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journal of Bionic Engineering 2024年第1期21卷 177-191页

作者： Yiwei Hao Yonghui cao Yingzhuo cao Xiong Mo Qiaogao Huang Lei gong guang Pan Yong cao School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Unmanned Vehicle Innovation Center Ningbo Institute of NPUNingbo 315103China Key Laboratory of Unmanned Underwater Vehicle Technology of Ministry of Industry and Information Technology Xi'an 710072China

Fish in nature exhibit a variety of swimming modes such as forward swimming,backward swimming,turning,pitching,etc.,enabling them to swim in complex scenes such as coral *** is still difficult for a robotic fish to swim autonomously in a confined area as a real ***,we develop an untethered robotic manta as an experimental platform,which consists of two flexible pectoral fins and a tail fin,with three infrared sensors installed on the front,left,and right sides of the head to sense the surrounding *** generate multiple swimming modes of the robotic manta and online switching of different modes,we design a closed-loop Central Pattern generator(CPg)controller based on distance information and use a combination of phase difference and amplitude of the CPg model to achieve stable and rapid adjustment of yaw *** verify the autonomous swimming ability of the robotic manta in complex scenes,we design an experimental scenario with a concave *** experimental results show that the robotic manta can achieve forward swimming,backward swimming,in situ turning within the concave obstacle,and finally exit from the area safely while relying on the perception of external obstacles,which can provide insight into the autonomous exploration of complex scenes by the biomimetic robotic ***,the swimming ability of the robotic manta is verified by field tests.

关键词： Biomimetic robotic manta Central Pattern generator Closed-loop control Backward swimming

Effect of Active–Passive Deformation on the Thrust by the Pectoral Fins of Bionic Manta Robot

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journal of Bionic Engineering 2024年第2期21卷 718-728页

作者： Yang Lu Shaomin Meng Cheng Xing Yiwei Hao Yonghui cao guang Pan Yong cao School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Unmanned Vehicle Innovation Center Ningbo Institute of NPUNingbo315103China State Key Lab of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou310027China Zhejiang Key Laboratory of Advanced Manufacturing Technology School of Mechanical EngineeringZhejiang UniversityHangzhou310027China

Bionic manta underwater vehicles will play an essential role in future oceans and can perform tasks,such as long-duration reconnaissance and exploration,due to their efficient *** manta wings’deformation is evident during the swimming *** improve the propulsion performance of the unmanned submersible,the study of the deformation into the bionic pectoral fin is *** this research,we designed and fabricated a flexible bionic pectoral fin,which is based on the Fin Ray®effect with active and passive deformation(APD)*** APD fin was actively controlled by two servo motors and could be passively deformed to variable *** APD fin was moved at 0.5 Hz beat frequency,and the propulsive performance was experimentally verified of the bionic pectoral fins equipped with different extents of *** results showed that the pectoral fin with active–passive deformed capabilities could achieve similar natural biological deformation in the wingspan *** average thrust(T)under the optimal wingspan deformation is 61.5%higher than the traditional passive deformed pectoral *** obtained results shed light on the design and optimization of the bionic pectoral fins to improve the propulsive performance of unmanned underwater vehicles(UUV).

关键词： Manta ray Bionic pectoral fin Fin Ray®effect Active-passive deformation(APD)

Association of daily sitting time and leisure-time physical activity with body fat among ***

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journal of Sport and Health Science 2024年第2期13卷 195-203页

作者： jingwen Liao Min Hu Kellie Imm Clifton j.Holmes jie Zhu Chao cao Lin Yang guangdong Provincial Key Laboratory of Physical Activity and Health Promotion Guangzhou Sport UniversityGuangzhou 510500China Scientific Research Center Guangzhou Sport UniversityGuangzhou 510500China Division of Epidemiology&genetics Department of Population and Public Health SciencesKeck School of Medicine of the University of Southern CaliforniaLos AngelesCA 90033USA Program in Physical Therapy Washington University School of MedicineSt.LouisMO 63110USA Center for Human Nutrition Washington University School of MedicineSt.LouisMO 63110USA Department of Plastic and Reconstructive Surgery Shanghai East HospitalTongji UniversityShanghai 200070China Department of Cancer Epidemiology and Prevention Research Alberta Health ServicesCalgary T2S 3C3Canada Department of Oncology and Community Health Sciences University of CalgaryCalgary T2N 1N4Canada

Background:Prolonged sitting and reduced physical activity lead to low energy ***,little is known about the joint impact of daily sitting time and physical activity on body fat *** investigated the independent and joint associations of daily sitting time and physical activity with body fat among ***:This was a cross-sectional analysis of *** representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or *** sitting time and leisure-time physical activity(LTPA)were self-reported using the global Physical Activity *** fat(total and trunk fat percentage)was determined via dual X-ray ***:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past *** fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both *** stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently *** the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/***:Prolonged daily sitting time was associated with increased body fat among *** higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

关键词： Adults Body fat distribution Physical activity Sitting time

Experimental and Numerical Investigation of Non-synchronous Blade Vibration Excitation in a Transonic Axial Compressor

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journal of Thermal Science 2024年第2期33卷 602-610页

作者： WANg Songbai WU Yadong CHEN Yong cao Zhipeng School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China AECC Sichuan gas Turbine Establishment Chengdu610500China

The complex flow phenomenon of rotating instability(RI) and its induced non-synchronous vibration(NSV) have become a significant challenge as they continuously increase aerodynamic *** study aims to provide an understanding of the non-synchronous blade vibration phenomenon caused by the rotating instability of a transonic axial compressor *** this case,blade vibrations and non-synchronous excitation are captured by strain gauges and unsteady wall pressure transducer *** numerical simulations for a full-annulus configuration are used to obtain the non-synchronous flow *** results show that the first-stage rotor blade exhibits an NSV close to the first bending mode;NSV is accompanied by a sharp increase in pressure pulsation;amplitude can reach 20%,and unsteady aerodynamic frequency will lock in a structural mode frequency when the blade vibrates in a large-amplitude *** predicted NSV frequency aligns well with the experimental *** dominant mode of circumferential instability flow structure is approximately 47% of the number blades,and the cell size occupies 2-3 pitches in the circumferential *** full-annulus unsteady simulations demonstrate that the streamwise oscillation of the shedding and reattachment vortex structure is the main cause of NSV owing to the strong interaction between the tip leakage and separation vortices near the suction surface.

关键词： non-synchronous vibration transonic axial compressor rotor blade rotating instabilities unsteady flow

Reduced-order modeling and vibration transfer analysis of a fluid-delivering branch pipeline that consider fluid–solid interactions

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Frontiers of Mechanical Engineering 2024年第2期19卷 75-97页

作者： Wenhao jI Hongwei MA Wei SUN Yinhang cao School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion Systems(Ministry of Education) Northeastern UniversityShenyang 110819China College of Power and Energy Engineering Harbin Engineering UniversityHarbin 150001China

The efficient dynamic modeling and vibration transfer analysis of a fluid-delivering branch pipeline(FDBP)are essential for analyzing vibration coupling effects and implementing vibration reduction ***,this study proposes a reduced-order dynamic modeling method suitable for FDBPs and then analyzes the vibration transfer *** the modeling method,the finite element method and absorbing transfer matrix method(ATMM)are integrated,considering the fluid–structure coupling effect and fluid *** dual-domain dynamic substructure method is developed to perform the reduced-order modeling of FDBP,and ATMM is adopted to reduce the matrix order when solving fluid ***,the modeling method is validated by experiments on an H-shaped branch ***,transient and steady-state vibration transfer analyses of FDBP are performed,and the effects of branch locations on natural characteristics and vibration transfer behavior are *** show that transient vibration transfer represents the transfer and conversion of the kinematic,strain,and damping energies,while steady-state vibration transfer characteristics are related to the vibration *** addition,multiple-order mode exchanges are triggered when branch locations vary in frequency-shift regions,and the mode-exchange regions are also the transformation ones for vibration transfer patterns.

关键词： fluid-delivering branch pipeline vibration transfer analysis reduced-order modeling fluid-solid interactions finite element method absorbing transfer matrix method