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Use of bionic inspired surfaces for aerodynamic drag reduction on motor vehicle body panels

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第7期12卷 543-551页

作者： Xiao-wen SONG guo-geng ZHANG yun wang Shu-gen HU Department of Mechanical Engineering Zhejiang University Hangzhou 310027 China

Inspired by the successful applications of biological non-smoothness,we introduced bionic non-smooth surfaces as appendices into vehicle body design,aiming to further reduce aerodynamic *** size range of the non-smooth units with pits and grooves was determined according to our analysis with the mechanisms underlying non-smooth unit mediated aerodynamic drag *** bionic non-smooth units reported here were designed to adapt the structure of a given vehicle body from the point of boundary layer control that reduces the burst and the loss of turbulent kinetic *** engine cover lid and vehicle body cap were individually treated with the non-smooth units,and the treated vehicles were subjected to aerodynamic drag coefficient simulation tests using the computational fluid dynamics(CFD) analysis *** simulation results showed that,in comparison with smooth surfaces,properly designed non-smooth surfaces can have greater effects on drag *** mechanism underlying drag reduction mediated by non-smooth surfaces was revealed by further analyses,in which the effects of non-smooth and smooth surfaces were directly compared.

关键词： Computational fluid dynamics(CFD) Bionics Non-smooth surface Aerodynamic drag reduction Vehicle body

Synergistic effect of gradient Zn content and multiscale particles on the mechanical properties of Al-Zn-Mg-Cu alloys with coupling distribution of coarse-fine grains

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1392-1405页

作者： Liangliang Yuan Mingxing guo Yi wang yun wang Linzhong Zhuang Institute of Effectiveness Evaluation of Flying Vehicle Beijing 100085China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China

This study investigated the influence of graded Zn content on the evolution of precipitated and iron-rich phases and grain struc-ture of the alloys,designed and developed the Al–8.0Zn–1.5Mg–1.5Cu–0.2Fe(wt%)alloy with high strength and *** the increase of Zn content,forming the coupling distribution of multiscale precipitates and iron-rich phases with a reasonable matching ratio and dispersion distribution characteristics is *** phenomenon induces the formation of cell-like structures with alternate distribu-tion of coarse and fine grains,and the average plasticity–strain ratio(characterizing the formability)of the pre-aged alloy with a high strength is up to *** reveal the evolution and influence mechanisms of multiscale second-phase particles and the corresponding high formability mechanism of the *** developed coupling control process exhibits considerable potential,revealing remarkable improvements in the room temperature formability of high-strength Al–Zn–Mg–Cu alloys.

关键词： Al–Zn–Mg–Cu alloy iron-rich phase high formability microstructure mechanisms

Separation of gibberellin A4 from A4 and A7 mixture by selective complex

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Chinese Chemical Letters 2010年第10期21卷 1206-1208页

作者： Lai Wen Hu Yong Yao Zhang yun guo Cong wang Zhi Min Jin College of Pharmaceutical Sciences Zhejiang University of Technology Hangzhou 310014 China

Gibberellin A4 is effectively separated from mixture of gibberellin A4 and its analogue gibberellin A7, in the form of its crystalline complex with N,N,N＇,N＇-tetramethylethylenediamine. After removing the tetramethy... 详细信息

关键词： Separation Gibberellin A4 Complex

Theoretical study on the effect of H_(2)O on the formation mechanism of NO_(x) precursors during indole pyrolysis

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Frontiers of Chemical Science and Engineering 2024年第6期18卷 99-112页

作者： Ziqi wang Jun Shen Xuesong Liu Sha wang Shengxiang Deng Hai Zhang yun guo School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The incineration technology of kitchen waste is one of the effective technologies to achieve the resource utilization of municipal solid *** is an important stage of *** is a rich initial product in the pyrolysis process of kitchen waste,and the presence of H_(2)O has a significant impact on the decomposition of indole to form NO_(x) ***,this study uses density functional theory method to study the effect of H_(2)O on the thermal decomposition of indole to produce NH_(3),HNCO,and *** H_(2)O participates in the reaction,it can provide oxidative groups to generate a new product HNCO,which is different from the previous findings by indole pyrolysis without the presence of H_(2)***,this study theoretically proves that NH_(3) is easier to form than *** is consistent with the phenomenon that NH_(3) release is higher than HCN release in pyrolysis *** addition,compared with the individual pyrolysis of indole,the participation of H_(2)O reduces the energy barriers for the formation of NH_(3) and HCN during indole pyrolysis,thereby promoting the formation of NH_(3) and HCN.

关键词： indole pyrolysis H_(2)O NO_(x)precursors DFT

Solar-powered miniature robot for on-site oil spill treatment under magnetic steering

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Science China(Technological Sciences) 2024年第7期67卷 2164-2175页

作者： wang Ben CHEN yunRui wang yun JI FengTong LI HongYuan NIU ShiChao HAN ZhiWu ZHANG YaBin guo ZhiGuang College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Ministry of Education Key Laboratory of New Processing Technology for Nonferrous Metals and Materialsand School of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China Key Laboratory for Bionic Engineering Ministry of Education Jilin UniversityChangchun 130022China Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials Ministry of Education Key Laboratory for the Green Preparation and Application of Functional MaterialsHubei UniversityWuhan 430062China Wellcome Trust/Cancer Research UK Gurdon Institute University of CambridgeCambridge CB21QNUK Department of Physiology Development and NeuroscienceUniversity of CambridgeCambridge CB21QNUK State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceBeijing Innovation Center for Engineering Science and Advanced TechnologyCollege of EngineeringPeking UniversityBeijing 100871China

Walking on the water surface is an effective method for miniature robots to transport payloads with dramatically decreased interfacial drag. Current aquatic robots reported are generally actuated by a beam of focused light that can trigger asymmetrical deformation, enabling the directional movement through horizontal momentum transfer of photoinduced actuation force to the water. However, the operations are heavily dependent on manual manipulation of the focused light, making the long-term actuation and application of the aquatic robots in vast scenarios challenging. Herein, we developed a kind of water striderinspired robot that can autonomously manage the motion on the water surface under solar irradiation, with their direction steerable by a magnetic field. The motion of this bioinspired robot on the water surface was achieved by the use of a solar cell panel as a driving module to enable propulsive motion based on the conversion of light-electric-mechanical energies. The superhydrophobic design of its leg surfaces enables the aquatic robots with weight-bearing and drag-reducing abilities. With the assistance of magnetic navigation, the bioinspired robot can continuously and controllably locomote to the oily spill floating on the water body and collect them with high efficiency. For further demonstration, the treatment of oil spills in a campus pool with high efficiency has also been achieved. This on-site oil-spill treating strategy, taking advantage of a home-made bioinspired robot actuated by natural sunlight under magnetic steering, shows great potential applications in water-body remediation.

关键词： miniature robot superhydrophobic water strider interfacial friction magnetic actuation

Heterointerface engineering of assembled CoP_(2) on N-modified carbon as efficient trifunctional electrocatalysts for Zn-Air batteries and overall water splitting

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Nano Research 2024年第5期17卷 3801-3809页

作者： Yan Chen Zhenrui Yang Juan wang yun Yang Xuedong He Yang wang Jiadong Chen Yaqing guo Xin wang Shun wang Huile Jin Wenzhou Key Lab of Advanced Energy Storage and Conversion Zhejiang Province Key Lab of Leather EngineeringCollege of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China Zhejiang Engineering Research Center for Electrochemical Energy Materials and Devices Institute of New Materials and Industrial TechnologiesWenzhou UniversityWenzhou 325035China School of Chemical and Biomedical Engineering Nanyang Technological UniversitySingapore 637459Singapore

Enhancing catalytic activity through modulating the interaction between N-doped carbon and metal phosphides clusters is an effective ***,the electronic structure modulation of CoP_(2) supported N-modified carbon(CoP_(2)/NC)has been designed and prepared as efficient electrocatalysts for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER).Notably,CoP_(2)/NC-1 catalyst exhibits impressive performance in alkaline media,with an ORR half-wave potential of 0.84 V,as well as OER and HER overpotentials of 290 and 129 mV(at 10 mA·cm^(−2)),*** addition,CoP_(2)/NC-1 produces a power density as high as 172.9 mW·cm^(−2),and excellent reversibility of 100 h at 20 mA·cm^(−2) in home-made Zn-air *** experimental results demonstrate that the synergistic interactions between N modified carbon substrate and CoP_(2) material significantly enhance the kinetics of ORR,OER,and *** functional theory(DFT)calculations reveal the strong electrons redistribution of CoP_(2) induced by high-density N atoms at the interface,thus optimizing the key intermediates and significantly lower the energy barrier of *** electronic adjustments of CoP_(2) greatly enhance its kinetics of ORR/OER/HER,leading to faster *** study provides profound insights into the specific modification of CoP_(2) by N-doped carbon,enabling the construction of efficient catalysts.

关键词： two-dimensional(2D)carbon metal-organic framework cobalt phosphide zinc air battery water splitting

Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

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Acta Geochimica 2024年第4期43卷 661-676页

作者： Jie wang yun Liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,Mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and Earth-Moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

Alternating spin splitting of electronic and magnon bands in two-dimensional altermagnetic materials

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Chinese Physics B 2024年第9期33卷 194-198页

作者： Qian wang Da-Wei Wu Guang-Hua guo Meng-Qiu Long yun-Peng wang School of Physics Central South UniversityChangsha 410083China

Unconventional antiferromagnetism dubbed as altermagnetism was first discovered in rutile structured magnets,which is featured by spin splitting even without the spin–orbital coupling *** interesting phenomenon has been discovered in more altermagnetic *** this work,we explore two-dimensional altermagnetic materials by studying two series of two-dimensional magnets,including MF4 with M covering all 3d and 4d transition metal elements,as well as TS2 with T=V,Cr,Mn,*** the magnetic symmetry operation of RuF4 and MnS2,it is verified that breaking the time inversion is a necessary condition for spin *** on symmetry analysis and first-principles calculations,we find that the electronic bands and magnon dispersion experience alternating spin splitting along the same *** work paves the way for exploring altermagnetism in two-dimensional materials.

关键词： two-dimensional altermagnetic materials altermagnetism spin splitting first-principles calculations

Hydrogen Bonds in Perovskite for Efficient and Stable Photovoltaic

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Chinese Journal of Chemistry 2024年第11期42卷 1284-1306页

作者： Tian-yun wang Yang-yang Hao Ming-zhe Zhu guo-rui Cao Zhong-min Zhou College of Chemistry and Molecular Engineering Qingdao University of Science and TechnologyQingdaoShandong266042 China College of Chemical Engineering Qingdao University of Science and TechnologyQingdaoShandong266042 China

Owing to their distinctive optical and physical properties,organic-inorganic hybrid perovskite materials have gained significant attention in the field of electronic devices,especially solar *** achievement of high-performance solar cells hinges upon the utilization of top-notch perovskite thin ***,the fabrication process involving solutions and the polycrystalline nature of perovskite result in the emergence of numerous defects within the perovskite films,consequently exerting a deleterious influence on the overall performance and stability of the *** the performance and stability of perovskite solar cells by additive engineering to suppress/passivate defects is a viable approach,which involves hydrogen bond interactions in these device engineering *** review explores the intrinsic hydrogen bonds in methylammonium and formamidium lead triiodide,while also considering cation rotations,phase transitions,and ***,the review classifies additives into distinct categories,including organic small molecules,polymers,nanodots,classical salts,ionic liquids,and molten *** various forms and characterization techniques of hydrogen bonds are discussed,as well as their potential synergistic effects in conjunction with other chemical ***,this review offers insights into the potential utilization of hydrogen bonds to further enhance the performance and stability of devices.

关键词： Perovskite solar cells Hydrogen bond Additive Performance Stability Charge transfer Inhibition Cooperative effects