检索结果-南通市图书馆

Engineering yolk.shell CuCo_(2)S_(4)@Cu_(2)O z.scheme nanoreactors for accelerating generation of value-added chemicals and of degradation multi-organic contaminants

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第25期156卷 54-63页

作者： Xue Feng lei z.ang College of Chemistry Liaoning University66 Chongshan Middle RoadShenyang 110036China

The synthesis of solar-driven chemical value-added products and the degradation of pollutants is a promising approach for sustainable development. However, achieving these work. via photocatalysts with efficient charge-separation, photo-absorption is challenging. A yolk.shell CuCo_(2)S_(4)@Cu_(2)O z.scheme nanoreactor (YS-CuCo_(2)S_(4)@Cu_(2) O-NR) with octahedron Cu_(2)O as the core and tubular CuCo2 S4 as the shell, has been synthesiz.d by regulating composition and morphology. YS-CuCo_(2)S_(4)@Cu_(2)O-NR shows superior photocatalytic activities for producing H_(2) O_(2) collaborates by selective oxidation of benz.l alcohol (BA) to high value-added benz.ldehyde (BAD)/utiliz.d Fenton-lik. reaction to degrade multi-pollutants through space-confinement effect, reaching 80% conversion and 99% selectivity of BA, a yield of 12 mM g^(−1) for H_(2)O_(2) and above 90% degradation efficiency for multi-pollutants. A photocatalysis nanoconfinement reactor system is proposed and demonstrated by using yolk.shell to enhance the performance of the chemical reaction. Mechanism studies show that the yolk.shell provides confined space to accelerate redox reaction k.netics;while the inner void promotes light harvesting and k.eps yolk.Cu_(2) O from deactivation;combined with the z.scheme charge transfer, engineering Cu^(+) /Cu^(2+) active composition, they are favorable for enhancing the H_(2) O_(2) generation and Fenton-lik. activity. These findings provide new opportunities for application of yolk.shell z.scheme metal-oxide-based photocatalysts.

关键词： Octahedron yolk.shell structure catalyz.r z.scheme charge transfer H2O_(2)generation Selective oxidation of BA Fenton-lik. reaction

Real-Time Control Strategy of Exosk.leton Locomotion Trajectory Based on Multi-modal Fusion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2023年第6期20卷 2670-2682页

作者： Tao z.en lei Yan College of Engineering Beijing Forestry UniversityNo.35East Qinghua RoadBeijing100083China

The exosk.leton robot is a typical man–machine integration system in the human *** ideal man–machine state is to achieve motion coordination,stable output,strong personaliz.tion,and reduce man–machine confrontation during *** order to achieve an ideal man–machine state,a Time-varying Adaptive Gait Trajectory Generator(TAGT)is designed to estimate the motion intention of the wearer and generate a personaliz.d gait *** can enhance the hybrid intelligent decision-mak.ng ability under human–machine collaboration,promote good motion coordination between the exosk.leton and the wearer,and reduce metabolic *** important feature of this controller is that it utiliz.s a multi-layer control strategy to provide locomotion assistance to the wearer,while allowing the user to control the gait trajectory based on human–robot Interaction(HRI)force and locomotion *** this article,a Temporal Convolutional Gait Prediction(TCGP)model is designed to learn the personaliz.d gait trajectory of the wearer,and the control performance of the model is further improved by fusing the predefined gait trajectory method with an adaptive interactive force control model.A human-in-the-loop control strategy is formed with the feedback.information to stabiliz. the motion trajectory of the output joints and update the system state in real time based on the feedback.from the inertial and interactive force *** experimental study employs able-bodied subjects wearing the exosk.leton for motion trajectory control to evaluate the performance of the proposed TAGT model in online *** from these evaluations demonstrate that the controller TAGT has good motor coordination and can satisfy the subject to control the motor within a certain range according to the walk.ng habit,guaranteeing the stability of the closed-loop system.

关键词： Exosk.leton Multi-layer control strategy Human–machine collaboration Time-varying adaptive gait Hybrid intelligent

A two-time-level split-explicit ocean circulation model (MASNUM) and its validation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2014年第11期33卷 11-35页

作者： HAN lei First Institute of Oceanography State Oceanic Administration Institute of Oceanography Chinese Academy of Sciences

A two-time-level, three-dimensional numerical ocean circulation model（named MASNUM） was established with a two-level, single-step Eulerian forward-back.ard time-differencing scheme. A mathematical model of large-scale oceanic motions was based on the terrain-following coordinated, Boussinesq, Reynolds-averaged primitive equations of ocean dynamics. A simple but very practical Eulerian forward-back.ard method was adopted to replace the most preferred leapfrog scheme as the time-differencing method for both barotropic and baroclinic modes. The forward-back.ard method is of second-order of accuracy, computationally efficient by requiring only one function evaluation per time step, and free of the computational mode inherent in the three-level schemes. This method is superior to the leapfrog scheme in that the maximum time step of stability is twice as large as that of the leapfrog scheme in staggered meshes thus the computational efficiency could be doubled. A spatial smoothing method was introduced to control the nonlinear instability in the numerical integration. An ideal numerical experiment simulating the propagation of the equatorial Rossby soliton was performed to test the amplitude and phase error of this new model. The performance of this circulation model was further verified with a regional（northwest Pacific） and a quasi-global（global ocean simulation with the Arctic Ocean excluded） simulation experiments. These two numerical experiments show fairly good agreement with the observations. The maximum time step of stability in these two experiments were also investigated and compared between this model and that model which adopts the leapfrog scheme.

关键词： ocean circulation model forward-back.ard method equatorial Rossby soliton Yellow Sea Cold Water Mass

On Temperature and Strain Rate Dependent Strain Localiz.tion Behavior in Ti-6.5Al-3.5Mo-1.5z.-0.3Si Alloy

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2013年第3期29卷 273-278页

作者： B.z.ang L.M.lei X.L.Jiang z.M.Song X.Huang G.P.z.ang k.y Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern University Titanium Alloys Laboratory Beijing Institute of Aeronautical Materials AVIC commercial Aircraft Engine Co. Ltd. Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

Deformation behaviors of Ti-6.5Al-3.5Mo-1.5z.-0.3Si alloys with α/β lamellar structure were investigated systematically at different temperatures from room temperature to 950 ~C and different strain rates. Results reveal that when the deformation temperature is higher than a critical temperature of 600℃, an evident transition of deformation behavior from localiz.d shear banding to α/β lamella k.nk.ng, flow softening and temperature/strain rate-dependent peak.flow stress occurred in the alloy. The critical conditions for the occurrence of internal crack.ng and strain localiz.tion behavior associated with temperature and strain rate were determined.

关键词： Titanium alloy Hot work.ng Temperature Strain rate Shear band

Lie Triple Derivations on von Neumann Algebras

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2018年第5期39卷 817-828页

作者： lei LIU School of Mathematics and Statistics Xidian University School of Mathematical Sciences Fudan University

Let A be a von Neumann algebra with no central abelian projections. It is proved that if an additive map δ :A → A satisfies δ([[a, b], c]) = [[δ(a), b], c] + [[a, δ(b)], c] +[[a, b], δ(c)] for any a, b, c∈ A with ab = 0(resp. ab = P, where P is a fixed nontrivial projection in A), then there exist an additive derivation d from A into itself and an additive map f :A → z. vanishing at every second commutator [[a, b], c] with ab = 0(*** = P) such that δ(a) = d(a) + f(a) for any a∈ A.

关键词： Derivations Lie triple derivations von Neumann algebras

An Insight into the Second-Harmonic Current Reduction Control Strategies in Two-Stage Converters

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Energy Engineering 2022年第3期119卷 1179-1196页

作者： lei Ren lei z.ang School of Electrical Engineering Nantong UniversityNantong226019China

Due to the components at twice the fundamental frequency of output voltage in the instantaneous output power of a two-stage single-phase inverter(TSI),the second harmonic current(SHC)is generated in the frontend dc-dc converter(FDC).To reduce the SHC,optimiz.ng the control strategy of the FDC is an effective and costless *** view of visual impedance,this paper conducts an intensive study on the SHC reduction *** of the SHC is illustrated ***,the equivalent circuit models of the FDC under different control strategies are proposed to analyse the SHC propagation *** derived model can offer a better insight into how the inductor SHC is affected by the control *** to the derived models,a synthesis of different control strategies is presented and the relevant parameters are listed for control design to achieve better suppression *** benefits and limitations of these control strategies are also *** on the proposed equivalent circuit models,several optimiz.tion methods are proposed to enhance the effect.A 1500 VA TSI prototype is built and simulated on MATLAB/Simulink.verifying the effectiveness of the proposed optimiz.tion *** paper is aimed to provide a guideline for the control design and control optimiz.tion of the TSIs.

关键词： Two-stage single-phase inverter(TSI) second harmonic current(SHC) equivalent circuit models optimiz.tion

Orientational Isomerism and Its Reactivity of a Main Group Sandwich Anion[Ge_(9)-In-Ge_(9)]^(5-)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第19期41卷 2432-2438页

作者： Hong-lei Xu lei Qiao z.ong Ming Sun State k.y Laboratory of Elemento-Organic Chemistry Tianjin Key Lab of Rare Earth Materials and ApplicationsSchool of Material Science and EngineeringNankai UniversityTianjin 300350China

Two isomers of a sandwich-type anion [Ge_(9)-In-Ge_(9)]^(5–) were synthesiz.d by controlling the chelating agents (2,2,2-crypt/18-C-6). Further reactions with early/late transition metal complexes, Mo(CO)_(6) and Ni(COD)_(2), respectively, yielded two new types of inorganic sandwich derivatives: a half-sandwich cluster [Ge_(9)-In-Mo(CO)_(5)]^(3–) with a low-valence In(I) center and an unsymmetrical sandwich-type cluster {[(Ni@Ge_(9))In(Ni_(0.648)@Ge_(9))]}^(5–) due to the insertion of Ni atoms, respectively. The isolation of these new derivatives demonstrates the reactivity of sandwich-type [Ge_(9)-In-Ge_(9)]^(5–) acting as the precursor, which provides some enlightenment for constructing new inorganic sandwich compounds.

关键词： Sandwich complex Cluster compounds Main group elements Germanium Indium

Toward developing Ti alloys with high fatigue crack.growth resistance by additive manufacturing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第1期132卷 166-178页

作者： F.Wang L.M.lei X.Fu L.Shi X.M.Luo z.M.Song G.P.z.ang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China AECC Commercial Aircraft Engine Co. Ltd.Shanghai 201306China

Fatigue crack.growth behaviors were investigated by three-point bending tests for TA19 alloy fabricated by laser metal deposition and four k.nds of heat-treated *** crack.growth resistance of the TA19 samples in the near-threshold regime and Paris regime was evaluated through the experimental characteriz.tion and theoretical analysis of the interaction between fatigue crack.andα/βphase inter-face,columnar prior-βgrain boundary and colony *** results show that in the near-threshold regime,the fatigue crack.propagation threshold and resistance increase with the increase of widths of lamellarαp phases and colonies,and the decrease of the number ofαlaths with an angle(ϕ)relative to the applied stress direction ranging from 75°to 90°.In the Paris regime,the fatigue crack.ng path can be deflected at colony boundaries or columnar prior-βgrain *** larger the deflection angle,the more tortuous the crack.ng path and the lower the fatigue crack.growth *** angle(γ)of the columnar prior-βgrain growth direction relative to the build direction affects not onlyϕof differentαvariants,but also the fatigue crack.ng path deflection angle(θij)at columnar prior-βgrain *** optimal combination ofγ=0°-15°-0°-15°for several adjacent columnar prior-βgrains is derived from the theoretical analysis,and that can effectively avoidϕbeing in the range from 75°to 90°and mak.θij as large as *** findings provide a guide for the selection of scanning strategies and process parameters to additively manufacture Ti alloys with high fatigue damage tolerance.

关键词： Ti alloy Fatigue crack.growth Additive manufacturing Phase interface Grain boundary

Redesign of the gStore system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2018年第4期12卷 623-641页

作者： Li z.NG lei z.U School of Electronics Engineering and Computer Science Peking University Beijing 100871 China Beijing Institute of Big Data Research Beijing 100871 China

gStore is an open-source native Resource Description Framework.（RDF） triple store that answers SPARQL queries by subgraph matching over RDF graphs. However, there are some deficiencies in the original system design, such as answering simple queries （including one-triple pattern queries）. To improve the efficiency of the system, we reconsider the system design in this paper. Specifically, we propose a new query plan generation module that generates different query plans according to the structures of query graphs. Furthermore, we re-design our vertex encoding strategy to achieve more pruning power and a new multi-join algorithm to speed up the subgraph matching process. Extensive experiments on synthetic and real RDF datasets show that our method outperforms the state-of-the-art algorithms significantly.

关键词： graph database subgraph matching RDF management SPARQL query