检索结果-南通市图书馆

A novel supercapacitor-fuel cell hybrid cell

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第Z1期25卷 12-18页

作者： WANG Y ZHENG Jim p Department of Electrical and Computer Engineering Florida A&M University and Florida State University Tallahassee FL 32310 USA Department of Electrical and Computer Engineering Florida A&M University and Florida State University Tallahassee FL 32310 USA

A monolithic hybrid fuel cell (MHFC) with a novel configuration was proposed in an effort to improve the fuel cell performance during instantaneous power changes. A modified direct methanol fuel cell (DMFC) with a layer of hydrous ruthenium dioxide (RuO2·xH2O) sandwiched between the anode catalyst layer and membrane was used to demonstrate the principle of the MHFC. Experimental results indicate that the RuO2·xH2O layer is equivalent to a resistor-capacitor transmission line and functions similar to a capacitor in parallel with the anode electrode. The improvement in dynamic response of the MHFC was experimentally confirmed under step current change and square current pulse operating. The ionic conductivity of the RuO2·xH2O layer was also obtained.

关键词： hybrid devices direct methanol fuel cells hydrous ruthenium dioxide dynamic response

A Chicken's Egg as a Reaction Vessel to Explore Biomineralization

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2007年第3期4卷 133-141页

作者： Tanmay Bera p. Ramachandrarao Department of Metallurgical Engineering Institute of TechnologyBanaras Hindu UniversityVaranasi 221005India International Advanced Research Centre for powder Metallurgy and other New Materials(ARCI)-Balapur Hyderabad 500005India

Natural composites, formed through biomineralization, have highly ordered structures which have been aptly explored for functional applications. Though the role of organic phases has been well understood in biomineralization, not enough attention has been paid to the role of bio-membranes which are often found encapsulating the chamber in which mineralization occurs. We have used the natural protein and semi-permeable membrane of chicken eggs to grow different materials such as ceramics, semi-metals and metals to understand the role of bio-membranes in biomineralization. We here report the successful biomimetic synthesis of calcite, cadmium sulphide, and silver having homogeneous morphologies. We have found that the membrane operates like a tuned gateway, playing a significant role in controlling the morphology of the inorganic crystals formed during biomineralization.

关键词： biomimetics biomineralization bio-membranes proteins organic-inorganic interface eggs

Abrasion of ultrafine WC-Co by fine abrasive particles

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2007年第6期17卷 1287-1293页

作者： p. V. Krakhmalev Department of Mechanical and Materials Engineerin g Karlstad University SE-651 88 Karlstad Sweden

Abrasive wear of a series of WC-(5%-14%, mass fraction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used. The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage. This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

关键词： WC-Co合金耐磨性边缘磨损微观效应

Identifying the general trend of activity of non-stoichiometric metal oxide phases for CO oxidation on pd(111)

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第6期62卷 784-789页

作者： Ziyun Wang p.Hu School of Chemistry and Chemical Engineering Queen's University Belfast

Oxidation state changes under reaction conditions are very common in heterogeneous catalysis. However, due to the limitation of experiment and computational methods, the relation between oxidation state and catalytic activity is not clear. Herein, we obtain the most stable structures of palladium oxide films with different oxidation states on palladium metal surfaces using density functional theory calculations and a state-of-the-art optimization method, namely the particle swarm optimization. These structures clearly show the process of palladium oxide film formation on metallic surfaces. Using CO oxidation as a model reaction, we find that the activities increase first and then decrease with the increase of oxidation states, peaking at pd_4O_3. Our findings offer an understanding of the phase transformation and the activity of non-stoichiometric phases.

关键词： DFT non-stoichiometric oxide CO oxidation

The theory of interaction between wave and basic flow

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2008年第3期17卷 1138-1146页

作者：冉令坤 John p.Boyd Laboratory of Cloud-precipitation physics and Severe Storms (LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences Department of Atmospheric Oceanicand Space ScienceUniversity of MichiganAnn ArborMichiganUSA

This paper investigates the interaction between transient wave and non-stationary and non-conservative basic flow. An interaction equation is derived from the zonally symmetric and non-hydrostatic primitive equations in Cartesian coordinates by using the Momentum-Casimir method. In the derivation, it is assumed that the transient disturbances satisfy the linear perturbation equations and the basic states are non-conservative and slowly vary in time and space. The diabatic heating composed of basic-state heating and perturbation heating is also introduced. Since the theory of wave-flow interaction is constructed in non-hydrostatic and ageostrophic dynamical framework, it is applicable to diagnosing the interaction between the meso-scale convective system in front and the background flow. It follows from the local interaction equation that the local tendency of pseudomomentum wave-activity density depends on the combination of the perturbation flux divergence second-order in disturbance amplitude, the local change of basic-state pseudomomentum density, the basic-state flux divergence and the forcing effect of diabatic heating. Furthermore, the tendency of pseudomomentum wave-activity density is opposite to that of basic-state pseudomomentum density. The globally integrated basic-state pseudomomentum equation and wave-activity equation reveal that the global development of basic-state pseudomomentum is only dominated by the basic-state diabatic heating while it is the forcing effect of total diabatic heating from which the global evolution of pseudomomentum wave activity results. Therefore, the interaction between the transient wave and the non-stationary and non-conservative basic flow is realized in virtue of the basic-state diabatic heating.

关键词： wave flow interaction pseudomomentum wave activity diabatic heating Momentum Casimir method

Graphene-driving novel strain relaxation towards AlN film and DUV photoelectronic devices

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2022年第7期11卷 1318-1319页

作者： Hieu.p.T.Nguyen New Jersey Institute of Technology Department of Electrical&Computer EngineeringNewarkNJ 07102USA

Graphene-driving strain-pre-store engineering enables the epitaxy of strain-free AlN film with low dislocation density for DUV-LED and the unique mechanism of strain-relaxation in QvdW epitaxy was demystified.

关键词： driving relaxation strain

Spin switching in antiferromagnets using Néel-order spin-orbit torques

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

Chinese physics B 2018年第10期27卷 88-95页

作者： p Wadley K W Edmonds School of physics and Astronomy University of Nottingham

Antiferromagnets offer considerable potential for electronic device applications. This article reviews recent demonstrations of spin manipulation in antiferromagnetic devices using applied electrical currents. Due to spin–orbit coupling in environments with particular crystalline or structural symmetries, the electric current can induce an effective magnetic field with a sign that alternates on the lengthscale of the unit cell. The staggered effective field provides an efficient mechanism for switching antiferromagnetic domains and moving antiferromagnetic domain walls, with writing speeds in the terahertz regime.

关键词： spintronics antiferromagnetic current-induced torques magnetic domains

Three-dimensional electric potential induced by a point singularity in a multilayered dielectric medium

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2019年第9期40卷 1327-1334页

作者： Xu WANG p. SCHIAVONE School of Mechanical and power Engineering East China University of Science and Technology Shanghai 200237 China Department of Mechanical Engineering University of Alberta 10-203 Donadeo Innovation Centre for Engineering Edmonton Alberta T6G 1H9 Canada

A simple and effective method is proposed to derive the three-dimensional electric potential induced by a point singularity of any type in an N-phase dielectric medium composed of N-2 intermediate dielectric layers of equal thickness encased in two semi-infinite dielectric media. The point singularity can include a point charge or a point electric dipole. The original boundary value problem for the N-phase medium is reduced to the determination of a single unknown three-dimensional harmonic function through satisfaction of the continuity conditions across all of the N-1 perfect planar interfaces. The single harmonic function can be completely determined after analytically solving the resulting linear recurrence relations, which are independent of the type and the specific location of the singularity. When the singularity is a point charge, we obtain the self-energy of the point charge expressed in terms of a single function and the Coulomb force on the point charge expressed in terms of the negative derivative of this function.

关键词： multilayered dielectric medium point charge point electric dipole linear recurrence relation analytical solution

The applicability of soil flushing technology in a metallurgical plant

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2018年第1期5卷 70-77页

作者： p. p. Manca p. Caredda G. Orru DICAAR Department of Civil Engineering Environmental and Architecture University of Cagliari Cagliari Italy

Soil flushing technology is an ＇in situ＇ remediation technique involving the injection of a liquid solution. Applications of the soil flushing technique depend on the leachability of the pollutants and the environmental compatibility and total volumes of the solutions used. Therefore, experiments should consider these aspects by simulating the real phenomenon and using the most suitable reagents for the leachability of the different mineralogical forms present. Thirty- one laboratory tests were carried out （in batch and becker） to the complete exhaustion of the leaching capacity according to pH measurements. The reaction kinetics were studied by producing more than 300 solution samples during which the principal heavy metal concentrations, pH and Eh were measured. Leaching solutions containing various concentrations of hydrochloric, sulphuric, nitric and acetic acids were used. Mercury was leached using potassium iodide and acetic acid （pH 2）. Analytes such as arsenic, cadmium, mercury, lead, selenium and zinc proved to be leachable in the investigated soil layer. However, high removal efficiencies could be obtained using different typological solutions, concentrations and volumes. The paper discusses the applicability of the soil flushing technique for different heavy metal contents and pH conditions of the flushing solution.

关键词： Soil flushing Metallurgical plant Heavy metal leaching