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The configuration of Au^(δ+)-ZrO_(2)^(δ−)species induced activation enh.nces electrocatalytic CO_(2)to formate conversion

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nano Research 2024年第7期17卷 6006-6015页

作者： Yongjian Jia Yadi Zh.ng Mengque Lin Yangyang Ch.ng Yanjie xu national Engineering Research Center for Technology and Equipment of Environmental Deposition Lanzhou Jiaotong UniversityLanzhou 730070China Key Lab of Opt-Electronic Technology and Intelligent Control of Ministry of Education Lanzhou Jiaotong UniversityLanzhou 730070China School of Environmental Engineering and Chemistry Luoyang Institute of Science and TechnologyLuoyang 471023China

Electrochemical CO_(2)conversion into value-added chemicals is a promising technology to solve the greenhouse effect and recycle chemical ***,the electrochemical CO_(2)reduction reaction(e-CO_(2)RR)is seriously compromised by weak CO_(2)adsorption and a rough CO_(2)activation process based on the chemical inertness of the CO_(2)molecule and the formed fragile metal–C/O *** this paper,we designed and fabricated Au particles embedded in ZrO_(2).The configuration of Au particles being of positive charge and ZrO_(2)with.negative charge is induced and generated by metal–support interactions(MSIs).As a result,Au/ZrO_(2)@C presents a big difference in the CO_(2)conversion compared with the known work,affording a formate yield of 112.5μmol·cm^(−2)·h^(−1)at−1.1 V *** hydrogen electrode(RhE),and a max formate Faradaic efficiency of up to 94.1%at−0.9 V *** superior performance was attributed to the activated Au–ZrO_(2)interface to form the Au^(δ+)*** insitu Fourier transform infrared(FTIR)spectroscopy and theoretical calculations show that the MSIs configuration can be inclined to the*OCO intermediate generation on Au^(δ+)species activating CO_(2)molecules and th.n accelerate the formation of the*OChO intermediate in e-CO_(2)RR,thereby favoring the CO_(2)conversion to formate.

关键词： electrochemical CO_(2)reduction reaction(e-CO_(2)RR) Au_(δ+)species formic acid *OChO intermediate metal-support interactions

A new high-Precision and Lightweight Detection Model for Illegal Construction Objects Based on Deep Learning

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Tsinghua Science and Technology 2024年第4期29卷 1002-1022页

作者： Wenjin Liu Lijuan Zhou Shudong Zh.ng ning Luo Min xu School of Cyberspace Security(School of Cryptology) Hainan UniversityHaikou 570228China School of Information Engineering Capital Normal UniversityBeijing 100048China

Illegal construction has caused serious harm around the world. however, current methods are difficult to detect illegal construction activities in time, and the calculation complexity and the parameters of them are large. To solve these challenges, a new and unique detection method is proposed, which detects objects related to illegal buildings in time to discover illegal construction activities. Meanwhile, a new dataset and a high-precision and lightweight detector are proposed. The proposed detector is based on the algorithm You Only Look Once (YOLOv4). The use of Densenet as the backbone of YDhnet enables better feature transfer and reuse, improves detection accuracy, and reduces computational costs. Meanwhile, depthwise separable convolution is employed to lightweight the neck and head to further reduce computational costs. Furthermore, h-swish is utilized to enh.nce non-linear feature extraction and improve detection accuracy. Experimental results illustrate that YDhnet realizes a mean average precision of 89.60% on the proposed dataset, which is 3.78% higher th.n YOLOv4. The computational cost and parameter count of YDhnet are 26.22 GFLOPs and 16.18 MB, respectively. Compared to YOLOv4 and other detectors, YDhnet not only has lower computational costs and higher detection accuracy, but also timely identifies illegal construction objects and automatically detects illegal construction activities.

关键词： object detection lightweight illegal buildings illegal construction objects high-precision

Exploring multiple phases and first-order phase transitions in Kármán Vortex Street

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Science Ch.na(Physics,Mech.nics & Astronomy) 2024年第11期67卷 47-54页

作者： xu Li Xing Xiang Tingting xue Limin Wang Xiaosong Ch.n School of Systems Science and Institute of nonequilibrium Systems Beijing Normal UniversityBeijing 100875China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy ofSciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Kármán Vortex Street, a fascinating ph.nomenon of fluid dynamics, has intrigued the scientific community for a long time. Many researchers have dedicated their efforts to unraveling the essence of this intriguing flow pattern. here, we apply the lattice Boltzmann method with curved boundary conditions to simulate flows around a circular cylinder and study the emergence of Kármán Vortex Street using the eigen microstate approach, which can identify phase transition and its order-parameter. At low Reynolds number, there is only one dominant eigen microstate W_(1) of laminar flow. At Re_(c)^(1)= 53.6, there is a phase transition with the emergence of an eigen microstate pair W^(2,3) of pressure and velocity fields. Further at Re_(c)^(2)= 56, there is another phase transition with the emergence of two eigen microstate pairs W^(4,5) and W^(6,7). Using the renormalization group theory of eigen microstate,both phase transitions are determined to be first-order. The two-dimensional energy spectrum of eigen microstate for W^(1), W^(2,3) after Re_(c)^(1), W^(4-7) after Re_(c)^(2) exhibit-5/3 power-law behavior of Kolnogorov's K41 theory. These results reveal the complexity and provide an analysis of the Kármán Vortex Street from the perspective of phase transitions.

关键词： Kármán Vortex Street first-order phase transition eigen microstate approach renormalization group theory of eigen microstate

Biomimetic soft robotic wrist with 3-DOF motion and stiffness tunability based on ring-reinforced pneumatic actuators and a particle jamming joint

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Science Ch.na(Technological Sciences) 2024年第3期67卷 774-790页

作者： hU TeTe LU XinJiang YI Jian WAnG Yuhui xu Du State Key Laboratory of Precision Manufacturing for Extreme Service Performance School of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China

The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom(3-DOF) orienting tasks and regulating stiffness according to variations in interaction forces. however, few soft robotic wrists simultaneously demonstrate dexterous 3-DOF motion and variable stiffness;in addition, they do not fully consider a soft-rigid hybrid structure of integrated muscles and two carpal *** this study, we developed a soft-rigid hybrid structure to design a biomimetic soft robotic wrist(BSRW) that is capable of rotating in the x and y directions, twisting around the z-axis, and possessing stiffness-tunable capacity. To actuate the BSRW, a lightweight soft-ring-reinforced bellows-type pneumatic actuator(SRBPA) with large axial, linear deformation(η_(lcmax)=70.6%,η_(lemax)=54.3%) and small radial expansion(η_(demax)=3.7%) is designed to mimic the motion of skeletal muscles. To represent the function of two-carpal rows, a compact particle-jamming joint(PJJ) that combines particles with a membrane-covered ballsocket mech.nism is developed to achieve various 3-DOF motions and high axial load-carrying capacity(>60 n). By varying the jamming pressure, the stiffness of the PJJ can be adjusted. Finally, a centrally positioned PJJ and six independently actuated SRBPAs, which are in an inclined and antagonistic arrangement, are sandwiched between two rigid plates to form a flexible,stable, and compact BSRW. Such a structure enables the BSRW to have a dexterous 3-DOF motion, high load-carrying ability,and stiffness tunability. Experimental analysis verify 3-DOF motion of BSRW, producing force of 29.6 n and 36 n and torque of2.2 nm in corresponding rotations. Moreover, the range of rotational angle and stiffness-tuning properties of BSRW are studied by applying jamming pressure to the PJJ. Finally, a system combining a BSRW and a soft enclosing gripper is proposed to demo

关键词： pneumatic soft actuators particle jamming robotic wrist soft robotics stiffness-tunable

Effect of icosahedral phase formation on the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li(in wt.%)based alloys

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Journal of Magnesium and Alloys 2024年第1期12卷 225-236页

作者： Shuo Wang Daokui xu Dongliang Wang Zhiqiang Zh.ng Baojie Wang Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang110819China Key Laboratory of nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Engineering Research Center of Advanced Materials Preparing Technology Ministry of EducationNortheastern UniversityShenyang110819China School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Binzhou Institute of Technology BinzhouShandong Province256606China Sh.ndong Key Laboratory of Advanced Aluminium Materials and Technology BinzhouShandong Province256606China

Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M naCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC *** regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li ***,the SCC of the two alloys was concerned with hydrogen embrittlement(hE)mech.nism.

关键词： Magnesium-lithium alloy Stress corrosion cracking I-phase Fracture analysis

Optically levitated micro gyroscopes with an Mhz rotational vaterite rotor

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Microsystems & nanoengineering 2024年第3期10卷 219-227页

作者： Kai Zeng Xiangming xu Yulie Wu xuezh.ng Wu Dingbang Xiao College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China College of Information and Communication National University of Defense TechnologyWuhan 430000China Key Laboratory of Satellite navigation Technology National University of Defense TechnologyChangsha 410073China

The field of levitated optomech.nics has experienced significant advancements in manipulating the translational and rotational dynamics of optically levitated particles and exploring their sensing *** concept of using optically levitated particles as gyroscopes to measure angular motion has long been explored but has not yet been proven either theoretically or *** this study,we present the first rotor gyroscope based on optically levitated high-speed rotating *** gyroscope is composed of a micrometer-size ellipsoidal vaterite particle that is driven to rotate at Mhz frequencies in a vacuum *** an external angular velocity is input,the optical axis deviates from its initial position,resulting in ch.nges in the frequency and amplitude of the rotational *** analyzing these ch.nges,the angular velocity of the input can be accurately detected,making it the smallest rotor gyroscope in the *** angular rate bias instability of the gyroscope is measured to be 0.08°/s and can be further improved to as low as 10^(−9)°/h theoretically by cooling the motion and increasing the angular moment of the levitated *** work opens a new application paradigm for levitated optomech.nical systems and may pave the way for the development of quantum rotor gyroscopes.

关键词： particles rotational angular

Exact satisfiability and phase transition analysis of the regular(k,d)-CnF formula

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Frontiers of Computer Science 2024年第1期18卷 263-265页

作者： Guoxia nIE Daoyun xu Xi WAnG Zaijun Zh.nG College of Computer Science and Technology Guizhou UniversityGuiyang 550025China School of Mathematics and Statistics Qiannan Normal University for NationalitiesDuyun 558000China Key Laboratory of Industrial Automation and Mach.ne Vision of Qiannan Duyun 558000China

1Introduction The satisfiability(SAT)problem has been considered the"seed"of other nP-complete *** regular partial exact(k,d)-SAT problem is an important extension of the SAT *** any(k,d)-CnF formula with a variable set V,V'is a proper subset of V,the problem involves determining whether a truth assignment set on V'exists such that only a literal in each clause is *** V'=V,it is a regular exact(k,d)-SAT ***,both experimental verifications and theoretical analyses of k-SAT problem have shown that the ratioα(clause constraint density)of the number of clauses m to the number of variables n is an important parameter affecting the satisfiability of the formula[1].however,the regular(k,d)-SAT problem has the same clause constraint density d/k.

关键词： formula constraint exact

new strategy for boosting cathodic performance of low temperature solid oxide fuel cells via chlorine doping

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nano Research 2024年第9期17卷 8086-8094页

作者： Shaohua xu hao Qiu Sh.nsh.n Jiang Jingjing Jiang Wei Wang Xiaomin xu Wei Kong Tanaka Dennis Chivurugwi Arkadii Proskurin Daifen Ch.n Chao Su School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212100China Institute of Analysis and Testing Beijing Academy of Science and TechnologyBeijing 100089China State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China WA School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityPerthWA6102Australia Admiral Makarov national University of Shipbuilding Heroiv Ukrainy av.9Mykolaiv54025Ukraine

To enh.nce the performance and widespread use of solid oxide fuel cells(SOFCs),addressing the low-temperature(<650℃)electrochemical performance and operational stability issues of cathode materials is ***,we propose ... 详细信息

To enh.nce the performance and widespread use of solid oxide fuel cells(SOFCs),addressing the low-temperature(hemical performance and operational stability issues of cathode materials is ***,we propose an innovative approach to enh.nce oxygen ion mobility and electrochemical performance of perovskite oxide by substituting some oxygen sites with chlorine *** designed SrTa_(0.1)Fe_(0.9)O_(3-δ-x)Clx(x=0.05 and 0.10)exhibits improved performance compared to SrTa_(0.1)Fe_(0.9)O_(3-δ)(STF).SrTa_(0.1)Fe_(0.9)O_(2.95-δ)Cl_(0.05)(STFCl0.05)shows the lowest area-specific resistance(ASR)value on Sm0.2Ce0.8O1.9(SDC)*** 600℃,STFCl0.05 achieves an ASR value of 0.084Ω·cm^(2),and a single cell with STFCl0.05 reaches a higher peak power density(PPD)value(1143 mW·cm^(-2))th.n that with STF(672 mW·cm^(-2)).Additionally,besides exhibiting excellent oxygen reduction reaction(ORR)activity at lower temperatures,the STFCl0.05 cathode demonstrates good CO_(2)tolerance and operational *** cell operation lasts for 150 h,and single cell operation endures for 720 h without significant performance *** chlorine doping approach effectively enh.nces ORR activity and stability,making STFCl0.05 a promising cathode material for low-temperature SOFCs.

关键词： low-temperature solid oxide fuel cells(LT-SOFCs) oxygen reduction reaction(ORR) CO_(2)tolerance chlorine doping

Bioinspired supramolecular macrocycle hybrid membranes with enh.nced proton conductivity

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nano Research 2024年第2期17卷 797-805页

作者： Pengfei Yang Linlin xu Panagiotis Trogadas Marc-Olivier Coppens Yang Lan Centre for nature Inspired Engineering Department of Chemical EngineeringUniversity College LondonLondon WC1E 7JEUK

Enh.ncing the proton conductivity of proton exch.nge membranes(PEMs)is essential to expand the applications of proton exch.nge membrane fuel cells(PEMFCs).Inspired by the proton conduction mech.nism of bacteriorhodopsin,cucurbit[n]urils(CB[n],where n is the number of glycoluril units,n=6,7,or 8)are introduced into sulfonated poly(ether ether ketone)(SPEEK)matrix to fabricate hybrid PEMs,employing a nature-inspired chemical engineering(nICE)*** carbonyl groups of CB[n]act as proton-conducting sites,while the host–guest interaction between CB[n]and water molecules offers extra protonconducting ***,the molecular size of CB[n]aids in their dispersion with.n the SPEEK matrix,effectively bridging the unconnected proton-conducting sulfonic group domains with.n the SPEEK ***,all hybrid membranes exhibit significantly enh.nced proton ***,the SPEEK membrane incorporating 1 wt.%CB[8](CB[8]/SPEEK-1%)demonstrates the highest proton conductivity of 198.0 mS·cm^(−1) at 60°C and 100%relative humidity(Rh),which is 228%greater th.n that of the pure SPEEK membrane under the same ***,hybrid membranes exhibit superior fuel cell *** CB[8]/SPEEK-1%membrane achieves a maximum power density of 214 mW·cm^(−2),representing a 140%improvement over the pure SPEEK membrane(89 mW·cm^(−2))at 50°C and 100%*** findings serve as a foundation for constructing continuous proton-conducting pathways with.n membranes by utilizing supramolecular macrocycles as fuel cell electrolytes and in other applications.

关键词： supramolecular macrocycle proton conductivity cucurbit[n]uril proton exch.nge membrane fuel cell