检索结果-南通市图书馆

Reynolds-number scaling analysis on lift generation of a flapping and passive rotating wing with an inhomogeneous mass distribution

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 259-269页

作者： Suyang QIN Haotian HANG Yang xiang Hong liu J.C.Wu center for aerodynamics school of aeronautics and astronauticsshanghai jiao tong universityshanghai 200240china

Insects usually fly by passively rotating wings,which has been applied to the design of flapping-wing Micro-Air Vehicles(MAVs)to reduce mechanical *** this paper,a robotic passive rotating-wing model is designed to investigate wing kinematics and lift generation,which are measured by a high-speed camera and a force transducer,*** addition,flow fields are measured using the Particle Image Velocimetry(PIV).Experimental results demonstrate that passive rotating motion has a coordinative relationship with actively stroking *** the stroke amplitude or frequency increases,the rotating amplitude is *** characterize the active stroking motion,a driving Reynolds number Redrivingis defined,which varies from 68 to 366 in this *** the gravity center of the wing towards trailing ed ge induces the increase of additional torque M,which decreases the wing rotating amplitude and promotes the advance of wing *** find that the timing of wing rotation is gradually delayed and the mean lift coefficient C^(-)_(L)monotonously decreases as *** increasing the additional torque M,C^(-)_(L)is slightly improved and approaches to the lift coefficient of a real fruit fly at driving Re approximately equal to *** instantaneous lifts combined with the vortical structures further demonstrate that the lift generation associated with wing rotation is mainly attributed to the growth of the LeadingEdge Vortex(LEV)and the passive wake capture *** wake capture is influenced by LEV,reversal stroke motion and wing additional torque together,which can only maintain the lift at a high level for a considerable *** high-lift generation mechanisms of flapping and passive rotating flight could shed light on the simplified design of MAVs and the improvement of their aerodynamic performance.

关键词： Flapping flight Unsteady lift Passive rotation Vortex flow Leading-edge vortex

Superhydrophobic magnetic Fe_(3)O_(4) polyurethane sponges for oil-water separation and oil-spill recovery

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第5期139卷 160-169页

作者： Shiyu Wu Yunjie xiang Yaqi Cai Jingfu liu Sino-Danish College University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environment Hangzhou Institute for Advanced StudyUCASHangzhou 310024China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

The effective and affordable separation of oil and water,a crucial process in the safe han dling of environmental disasters such as crude oil spills and recovery of valuable resources is a highly sought-after yet challenging ***,superhydrophobic PU sponge was fab ricated for the fast and cost-effective adsorptive separation of oil and different organic sol vents from ***(OTS)-functionalized Fe_(3)O_(4)@SiO_(2)core-shell mi crospheres were dip-coated on the surface of porous materials via a dip-coating process thereby endowing them with *** to the hydrophobic interaction between OTS molecules and oil and increased capillary force in the micropores,the result ing superhydrophobic sponge served as a selective oil-sorbent scaffold for absorbing oil from oil-water mixtures,including oil-water suspensions and ***,after the recovery of the adsorbed oil via mechanical extrusion,these superhydrophobic materials could be reused multiple times and maintain their oil-water separation efficacy even afte 10 oil-water separation cycles.

关键词： Fe_(3)O_(4)@SiO_(2)-OTS polyurethane sponge Oil-water separation Adsorption capacity Oil-spill recovery

Hierarchical In_(2)S_(3)microflowers decorated with WO_(3)quantum dots:Sculpting S-scheme heterostructure for enhanced photocatalytic H_(2)evolution and nitrobenzene hydrogenation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第7期174卷 218-225页

作者： Yuan Lin Lv Chen Jianhua Zhang Yunyun gui Lijun liu Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile UniversityWuhan 430200China

Solar energy conversion and high-value chemical production are of utmost ***,the de-velopment of efficient photocatalysts with strong redox ability remains *** we report a unique 3D/0D In_(2)S_(3)/WO_(3)S-scheme heterojunction photocatalyst obtained by depositing WO_(3)quantum dots(QDs)onto hierarchical In_(2)S_(3)*** In_(2)S_(3)/WO_(3)composite exhibits outstanding visible light absorption,with a maximum optical response of up to 600 *** electronic interaction and charge separation at interfaces are explored by in situ X-ray photoelectron spectroscopy(XPS)and density func-tional theory(DFT)*** difference in work function causes In_(2)S_(3)to donate electrons to WO_(3)upon combination,leading to the formation of an internal electric field(IEF)at the *** to the IEF and bent energy bands,the transfer and separation of photogenerated charge carriers follow an S-scheme pathway within In_(2)S_(3)/WO_(3).Owing to the strong redox ability,spatial charge separation and lower H 2-generation barrier of S active sites,the optimized In_(2)S_(3)/WO_(3)heterojunctions show enhanced photocatalytic hydrogen evolution of 0.39 mmol h^(-1)g^(-1),6.7 times that of pristine In_(2)S_(3).In addition,the In_(2)S_(3)/WO_(3)S-scheme heterojunctions afford a remarkable activity for photocatalytic nitrobenzene hydro-genation with nearly 98%conversion and 99%selectivity of aniline within 1 *** work might present new insights into developing efficient S-scheme heterojunctions for various photocatalytic applications.

关键词： S-scheme heterojunctions In_(2)S_(3)microflowers WO_(3)quantum dots H_(2)production Electron transfer

Transition metal clusters with precise numbers of atoms anchored on graphdiyne as multifunctional electrocatalysts for OER/ORR/HER:a computational study

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 3107-3117页

作者： Xin-Yang liu Jing-Wei liu Gang Li Jing-xiang Zhao College of Chemistry and Chemical Engineering Harbin Normal UniversityHarbin 150025China

Subnanometer metal clusters play an increasingly important role in heterogeneous catalysis due to their high catalytic activity and *** this work,by means of the density functional theory(DFT) calculations,the catalytic activities of transition metal clusters with precise numbers of atoms supported on graphdiyne(TM_(1-4)@GDY,TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Pd,Ir,Pt) were investigated for oxygen evolution reactions(OER),oxygen reduction reactions(ORR) and hydrogen evolution reactions(HER).The computed results reveal that the Pd_(2),Pd_(4) and Pt_(1) anchored graphdiyne can serve as trifunctional catalysts for OER/ORR/HER with the overpotentials of 0.49/0.37/0.06,0.45/0.33/0.12 and 0.37/0.43/0.01 V,respectively,while Pd_(1) and Pt_(2)@graphdiyne can exhibit excellent catalytic performance for water splitting(OER/HER) with the overpotentials of 0.55/0.17 and 0.43/0.03 *** addition,Ni_(1) and Pd_(3) anchored GDY can perform as bifunctional catalysts for metal-air cells(OER/ORR) and fuels cells(ORR/HER) with the overpotentials of 0.34/0.32 and 0.42/0.04 V,***,by precisely controlling the numbers of atoms in clusters,the TM_(1-4) anchored graphdiyne can serve as promising multifunctional electrocatalysts for OER/ORR/HER,which may provide an instructive strategy to design catalysts for the energy conversation and storage devices.

关键词： Density functional theory Graphdiyne Single-cluster catalysts Multifunctional electrocatalysts Overpotential

Applying dynamic light scattering to investigate the self-assembly process of DNA nanostructures

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 316-320页

作者： Wei Yuan gui-Zhi Dong Hui Ning xiang-xiang Guan Jia-Feng Cheng Zi-Wei Shi Xiu-Ji Du Si-Wen Meng Dong-Sheng liu Yuan-Chen Dong CAS Key Laboratory of Colloid Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Dandong Bettersize Instruments Ltd. Dandong 118000China Key Laboratory of Organic Optoelectronics&Molecular Engineering of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084China Department of Chemistry Renmin University of ChinaBeijing 100872China

Understanding the dynamic assembly process of DNA nanostructures is important for developing novel strategy to design and construct functional *** this work,temperature-controlled dynamic light scattering(DLS)strategy has been applied to study the global assembly process of DNA origami and DNA *** the temperature dependent size and intensity profiles,the self-assembly process of various DNA nanostructures with different morphologies have been well-studied and the temperature transition ranges could be *** advantage of the DLS information,rapid preparation of the DNA origami and the brick assembly has been realized through a constant temperature *** results demonstrate that the DLS-based strategy provides a convenient and robust tool to study the dynamic process of forming hieratical DNA structures,which will benefit understanding the mechanism of self-assembly of DNA nanostructures.

关键词： Dynamic light scattering Self-assembly process DNA nanostructures Temperature transition ranges Rapid preparation

Flexible electrochemical capacitor based NiMoSSe electrode material with superior cycling and structural stability

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第7期35卷 456-460页

作者： Jingxuan liu Shiqi Zhao xiang Wu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

Constructing composited electrode material is considered to be an efficient strategy to improve their electrochemical *** can accelerate the charge transfer speed of ions and enhance the conductivity of ***,the formation of the hybrid structure can largely avoid the aggregation of two dimensional materials and increase the electrochemical active area of the *** this work,we synthesize NiMoSSe electrode materials on nickel foam by a facile hydrothermal *** prepared composite shows a specific capacitance of 1035 C/g at 1 A/g due to the synergistic effect between MoS_(2) and MoSe_(2) *** addition,the devices are assembled with NiMoSSe samples,which offers an energy density of 82.71 Wh/kg at a power density of 2700 W/kg.

关键词： Supercapacitors NiMoSSe Energy density Power density Cycling life

Multi-Timescale Distributed Approach to Generalized-Nash-Equilibrium Seeking in Noncooperative Nonconvex Games

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 791-793页

作者： Banghua Huang Yang liu Kit Ian Kou Weihua gui the School of Mathematical Sciences Zhejiang Normal UniversityJinhua 321004China IEEE the Key Laboratory of Intelligent Education Technology and Application of Zhejiang Province Jinhua 321004China the Faculty of Science and Technology University of MacaoMacaoChina the School of Automation Central South UniversityChangsha 410083China

Dear Editor,The distributed generalized-Nash-equilibrium(GNE)seeking in noncooperative games with nonconvexity is the topic of this *** by the sequential quadratic programming(SQP)method,a multi-timescale multi-agent system(MAS)is developed,and its convergence to a critical point of the game is *** illustrate the qualities and efficacy of the theoretical findings,a numerical example is elaborated.

关键词： letter seeking programming

Achieving Negatively Charged Pt Single Atoms on Amorphous Ni(OH)_(2)Nanosheets with Promoted Hydrogen Absorption in Hydrogen Evolution

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第10期16卷 213-224页

作者： Yue liu gui liu xiangyu Chen Chuang Xue Mingke Sun Yifei liu Jianxin Kang Xiujuan Sun Lin Guo School of Chemistry Beijing Advanced Innovation Center for Biomedical EngineeringKey Laboratory of Bio-inspired Smart Interfacial Science and TechnologyBeihang UniversityBeijing 100191People's Republic of China School of Chemistry Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of EducationXiangtan UniversityXiangtan 411105HunanPeople'Republic of China

Single-atom(SA)catalysts with nearly 100%atom utilization have been widely employed in electrolysis for decades,due to the outperforming catalytic activity and ***,most of the reported SA catalysts are fixed through the strong bonding between the dispersed single metallic atoms with nonmetallic atoms of the substrates,which greatly limits the controllable regulation of electrocatalytic activity of SA *** this work,Pt-Ni bonded Pt SA catalyst with adjustable electronic states was successfully constructed through a controllable electrochemical reduction on the coordination unsaturated amorphous Ni(OH)_(2)nanosheet *** on the X-ray absorption fine structure analysis and first-principles calculations,Pt SA was bonded with Ni sites of amorphous Ni(OH)_(2),rather than conventional O sites,resulting in negatively charged Pt^(δ-).In situ Raman spectroscopy revealed that the changed configuration and electronic states greatly enhanced absorbability for activated hydrogen atoms,which were the essential intermediate for alkaline hydrogen evolution *** hydrogen spillover process was revealed from amorphous Ni(OH)_(2)that effectively cleave the H-O-H bond of H_(2)O and produce H atom to the Pt SA sites,leading to a low overpotential of 48 mV in alkaline electrolyte at-1000 mA cm^(-2)mg^(-1)_(Pt),evidently better than commercial Pt/C *** work provided new strategy for the control-lable modulation of the local structure of SA catalysts and the systematic regulation of the electronic states.

关键词： Hydrogen evolution reaction Amorphous Pt single atoms Hydrogen spillover

LLM4CP:Adapting Large Language Models for Channel Prediction

在线全文

学校读者我要写书评

暂无评论

Journal of Communications and Information Networks 2024年第2期9卷 113-125页

作者： Boxun liu Xuanyu liu Shijian Gao xiang Cheng liuqing Yang State Key Laboratory of Advanced Optical Communication Systems and Networks School of ElectronicsPeking UniversityBeijing 100871China Internet of Things Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Internet of Things Thrust and Intelligent Transportation Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Department of Electronic and Computer Engineering and Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

Channel prediction is an effective approach for reducing the feedback or estimation overhead in massive multi-input multi-output (m-MIMO) systems. However, existing channel prediction methods lack precision due to model mismatch errors or network generalization issues. Large language models (LLMs) have demonstrated powerful modeling and generalization abilities, and have been successfully applied to cross-modal tasks, including the time series analysis. Leveraging the expressive power of LLMs, we propose a pre-trained LLM-empowered channel prediction(LLM4CP)method to predict the future downlink channel state information (CSI) sequence based on the historical uplink CSI sequence. We fine-tune the network while freezing most of the parameters of the pre-trained LLM for better cross-modality knowledge transfer. To bridge the gap between the channel data and the feature space of the LLM,preprocessor, embedding, and output modules are specifically tailored by taking into account unique channel characteristics. Simulations validate that the proposed method achieves state-of-the-art (SOTA) prediction performance on full-sample, few-shot, and generalization tests with low training and inference costs.

关键词： channel prediction massive multi-input multi-output(m-MIMO) large language models(LLMs) fine-tuning time-series