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Super-exchange effect induced by early 3d metal doping on NiFe_(2)O_(4)(001)surface for oxygen evolution reaction

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Journal of Energy Chemistry 2023年第3期78卷 21-29,I0002页

作者： Shuhao Wang Xinyan Liu Xiang Chen kamran dastafkan Zhong-Heng Fu Xin Tan Qiang Zhang Chuan Zhao School of Chemistry The University of New South WalesSydneyNSW 2052Australia Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina Integrated Materials Design Laboratory Department of Applied MathematicsResearch School of PhysicsThe Australian National UniversityCanberraACT 2601Australia

Understanding the intrinsic activity of oxygen evolution reaction(OER) is crucial for catalyst *** date,different metal-doping strategies have been developed to achieve this,but the involving mechanisms remain ***,the electronic structure of the transition metal-doped NiFe_(2)O_(4)(001) surface is scrutinized for OER intrinsic activity using density functional theory *** 3d-orbital filling metals(Ti,V,Cr,Mn,and Co) are introduced as dopants onto A-and B-layers of the NiFe_(2)O_(4)(001) surface,and variation of oxidation states over Fe sites is observed on *** the magnetic moment and charge transfer of surface cation sites reveals that the variation of Fe oxidation states originates from the super-exchange effect and is influenced by the t2g-electron configuration of 3d metal *** trend governs the generation of highly-active Fe3+sites on the B-layer,the adsorption strength of OER intermediates,i.e.,*O and*OH,and therefore the intrinsic *** finding of super-exchange mechanism induced by 3d early metal doping offers insights into electronic structure tailoring strategies for improving the intrinsic activity of OER electrocatalysts.

关键词： Oxygen evolution reaction NiFe spinel Oxidation states Super-exchange mechanism Density functional theory

Recent advances in spinel-type electrocatalysts for bifunctional oxygen reduction and oxygen evolution reactions

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Journal of Energy Chemistry 2021年第2期30卷 290-302,I0010页

作者： Xiao-Meng Liu Xiaoyang Cui kamran dastafkan Hao-Fan Wang Cheng Tang Chuan Zhao Aibing Chen Chuanxin He Minghan Han Qiang Zhang Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China School of Chemistry The University of New South WalesSydneyNSW 2052Australia AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory(ChEM-OIL) National Institute of Advanced Industrial Science and Technology(AIST)YoshidaSakyo-kuKyoto 606-8501Japan School of Chemical Engineering and Advanced Materials The University of AdelaideAdelaideSA 5005Australia College of Chemical and Pharmaceutical Engineering Hebei University of Science and TechnologyShijiazhuang 050018HebeiChina Shenzhen Key Laboratory of Functional Polymer College of Chemistry and Chemical EngineeringShenzhen UniversityShenzhen 518061GuangdongChina

The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electrolysers, fuel cells, and metal–air batteries emerge in response to the need for developing sustainable energy carriers, in which the oxygen evolution reaction and the oxygen reduction reaction play key roles. However, both reactions suffer from sluggish kinetics that restricts the reactivity. Therefore, it is vital to probe into the structure of the catalysts to exploit high-performance bifunctional oxygen electrocatalysts. Spinel-type catalysts are a class of materials with advantages of versatility, low toxicity, low expense, high abundance, flexible ion arrangement, and multivalence structure. In this review, we afford a basic overview of spinel-type materials and then introduce the relevant theoretical principles for electrocatalytic activity, following that we shed light on the structure–property relationship strategies for spinel-type catalysts including electronic structure, microstructure, phase and composition regulation,and coupling with electrically conductive supports. We elaborate the relationship between structure and property, in order to provide some insights into the design of spinel-type bifunctional oxygen electrocatalysts.

关键词： Spinel electrocatalyst Bifunctional energy electrocatalysis Oxygen evolution reaction Oxygen reduction reaction Structure–property relationship

Sea urchin‐like NiMoO_(4) nanorod arrays as highly efficient bifunctional catalysts for electrocatalytic/photovoltage‐driven urea electrolysis

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Chinese Journal of Catalysis 2022年第5期43卷 1267-1276页

作者： Chenxin Chen Suqi He kamran dastafkan Zehua Zou Qingxiang Wang Chuan Zhao Department of Chemistry and Environment Science Fujian Provincial Key Laboratory of Modern Analytical Science and Separation TechnologyMinnan Normal UniversityZhangzhou 363000FujianChina School of Chemistry and Materials&Manufacturing Futures Institute The University of New South WalesSydney 2052Australia

Developing multifunctional electrocatalysts with high catalytic activity,longterm stability,and low cost is essential for electrocatalytic energy ***,sea urchinlike NiMoO_(4) nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen *** NiMoO_(4)‐200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm^(–2).The NiMoO_(4)‐300/NF catalyst exhibits a prominent oxygen evolution reaction(OER)catalytic activity with an overpotential of 288 mV at 50 mA cm^(–2),as well as for urea oxidation reaction with an ultralow potential of 1.36 V at 10 mA cm^(–2).The observed difference in electrocatalytic activity and selectivity,derived by temperature variation,is ascribed to different lattice oxygen *** lattice oxygen of NiMoO_(4)‐300/NF is more than that of NiMoO_(4)‐200/NF,and the lattice oxygen is conducive to the progress of OER.A urea electrolyzer was assembled with Ni‐MoO_(4)‐200/NF and NiMoO_(4)‐300/NF as cathode and anode respectively,delivering a current density of 10 mA cm^(–2)at a cell voltage of merely 1.38 *** NiMoO_(4)nanorod arrays has also been successfully applied for photovoltage‐driven urea electrolysis and hydrogen production,revealing its great potential for solar‐driven energy conversion.

关键词： NiMoO4 nanorod Bifunctional electrocatalyst Urea electrolysis Photovoltage‐driven Lattice oxygen Sea urchin‐like

Design and Optimization of 3D Radial Slot Grain Configuration

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Chinese Journal of Aeronautics 2010年第4期23卷 409-414页

作者： Ali kamran School of Astronautics Beijing University of Aeronautics and Astronautics

Upper stage solid rocket motors （SRMS） for launch vehicles require a highly efficient propulsion system. Grain design proves to be vital in terms of minimizing inert mass by adopting a high volumetric efficiency with minimum possible sliver. In this arti- cle, a methodology has been presented for designing three-dimensional （3D） grain configuration of radial slot for upper stage solid rocket motors. The design process involves parametric modeling of the geometry in computer aided design （CAD） software through dynamic variables that define the complex configuration. Grain bum back is achieved by making new surfaces at each web increment and calculating geometrical properties at each step. Geometrical calculations are based on volume and change-in-volume calculations. Equilibrium pressure method is used to calculate the internal ballistics. Genetic algorithm （GA） has been used as the optimizer because of its robustness and efficient capacity to explore the design space for global optimum solution and eliminate the requirement of an initial guess. Average thrust maximization under design constraints is the objective function.

关键词： solid rocket motors 3D grains radial slot configuration internal ballistics computer aided design heuristic optimization genetic algorithm

Electro-optomechanical switch via tunable bistability and four-wave mixing

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Chinese Physics B 2019年第11期28卷 193-203页

作者： kamran Ullah Department of Physics Quaid-i-Azam University

We investigate the tunable bistable behavior of a hybrid nano-electro-optomechanical system(NEOMS) composed of S-shaped in the presence of two-level atoms, trapped inside a Fabry–Pérot cavity, and driven by a strong driving field and a weak probe field. The bistable behavior of the steady-state photon number and the mechanical steady-state positions are discussed. Further, we tune bistability by tuning all the coupling frequencies involved in the system and amplitude of the driving field. The present study provides the possibility of realization of a controllable optical switch depending on atom-field coupling, optomechanical coupling, electrostatic Coulomb coupling, and threshold power. In addition, we discuss that the non-linear effect of the hybrid NEOMS generates the four-wave mixing(FWM) process. Moreover, we show that the FWM process can be suppressed by the atom-field detuning and cavity-field detuning, which exhibits low photon transmission.

关键词： nano-electro-optomechanics nano-resonators two-level atom optical switch optical bistability four-wave mixing

An improved porous media model for nuclear reactor analysis

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Nuclear Science and Techniques 2016年第1期27卷 117-140页

作者： Roozbeh Vadi kamran Sepanloo Schools of Nuclear Safety Research and Radiation Protection Nuclear Science and Technology Research InstituteEnd of North Karegar Ave.P.O.Box:14359-836TehranIran

In this study, two modifications are proposed to mitigate drawbacks of the conventional approach of using the ‘‘Porous Media Model''(PMM) for nuclear reactor analysis. In the conventional approach, whole reactor core simplifies to a single porous medium and also, the resistance coefficients that are essential to using this model are constant values. These conditions impose significant errors and restrict the applications of the model for many cases,including accident analysis. In this article, the procedures for calculating the coefficients are modified by introducing a practical algorithm. Using this algorithm will result in obtaining each coefficient as a function of mass flow ***, the method of applying these coefficients to the reactor core is modified by dividing the core into several porous media instead of one. In this method, each porous medium comprises a single fuel assembly. PMM with these two modifications is termed ‘‘multi-region PMM'' in this study. Then, the multi-region PMM is introduced to a new CFD-based thermo-hydraulic code that is specifically devised for combining with neutronic *** CITVAP code, which solves multi-group diffusion equations, is the selected as the neutronic part for this study. The resulting coupled code is used for simulation of natural circulation in a MTR. A new semi-analytic method,based on steady-state CFD analysis is developed to verify the results of this case. Results demonstrate considerable improvement, compared to the conventional approach.

关键词：多孔介质模型模型分析反应器传统方法应用程序流体力学分析稳态计算 PMM

Influence of welding speed on corrosion behaviour of friction stir welded AA5086 aluminium alloy

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Journal of Central South University 2016年第6期23卷 1301-1311页

作者： kamran Amini Farhad Gharavi Department of Mechanical Engineering Tiran Branch Islamic Azad University

The plates of AA5086 aluminium alloy were joined together by friction stir welding at a fixed rotation speed of 1000 r/min various welding speeds ranging from 63 to 100 mm/*** behavior of the parent alloy(PA),the heat affected zone(HAZ),and the weld nugget zone(WNZ)of the joints were studied in 3.5%(mass fraction)aerated aqueous Na Cl solution by potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The corrosion susceptibility of the weldments increases when the welding speed increases to 63 and 100 mm/***,the value of corrosion rate in the weldments is lower than that in the ***,the corrosion current density increases with increasing the welding speed in the HAZ and the *** the contrary,the corrosion potential in the WNZ appears more positive than in the HAZ with decreasing the welding *** WNZ exhibits higher resistance compared to the HAZ and the PA as the welding speed *** results obtained from the EIS measurements suggest that the weld regions have higher corrosion resistance than the parent *** increasing the welding speed,the distribution and extent of the corroded areas in the WNZ region are lower than those of the HAZ *** the HAZ region,in addition to the pits in the corroded area,some cracks can be seen around the corroded areas,which confirms that intergranular corrosion is formed in this *** alkaline localized corrosion and the pitting corrosion are the main corrosion mechanisms in the corroded areas within the weld *** pits are observed within the weld regions.

关键词： friction stir welding aluminum alloy corrosion properties welding speed

Microstructural Evolution of NiTi47.7Cu6.3 Alloy during Hot Deformation

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Journal of Materials Science & Technology 2011年第10期27卷 951-960页

作者： Amir Etaati kamran Dehghani Mining and Metallurgical Eng.Dept. Amirkabir Univ.Tech.

In the present work, the hot workability and microstructural evolution of ***6.3 （at.%） shape memory alloy were investigated by using wedge-rolling test. The wedge specimens were subjected to hot rolling at the temperatures of 700-1000℃. The microstructural evolutions at the strains of 0.05, 0.15, 0.2, 0.25 and 0.3 were then characterized by optical microscopy and scanning electron microscopy （SEM） as well as energy dispersive spectrometry （EDS） technique. Depending on the deformation temperature and strain, the dynamic recrystallization （DRX） could occur, leading to the refining of the microstructure. At low temperatures of 700 and 800℃ there was no sign of DRX at all studied strains. At these temperatures, the formed fine needle-like precipitates pinned the grain boundaries and prevented them from bulging/migration. By contrast, at higher temperatures of 900 and 1000℃, the DRX took place at the critical strains lower than 0.25 and 0.15, respectively. However, at higher temperatures, strain-induced-boundary-migration （SIBM） mechanism resulted in the formation of DRX grains.

关键词： Deformation Wedge rolling test Dynamic recrystallization Ni-rich Nitinol NiTiCu

Numerical Modeling of the Stability of Horizontal Multidrain Oil Wells

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China Ocean Engineering 2015年第5期29卷 719-732页

作者： Ayub ELYASI kamran GOSHTASBI Faculty of Engineering Tarbiat Modares University

The stability of the horizontal multidrain wells is a crucial issue and several factors are involved in this matter, including in-situ stresses, magnitude and distribution as well as the mainbore trajectories. In this paper, this issue is evaluated by assuming different circumstances for the above mentioned factors, based on finite difference threedimensional modeling by using the finite difference numerical software, FLAC3 D. The stability of the mainbore and lateral branches is analyzed based on the Normalized Yielded Zone Area（NYZA） criterion, i.e. the ratio of the surrounding yielded cross-sectional area to the initial area of the well. Optimum mud pressures are obtained in the mainbore and lateral branches in different mainbore trajectories under three in-situ stress regimes. In addition, the stability of the junction where the lateral branches are bifurcated from the mainbore is assessed in those situations. The optimum trajectory of the mainbore, in which the junction has obtained the most stable condition, is selected in each stress regime. It was concluded that in the Normal Faulting（NF） stress regime, the mainbore and junction stability varies in relation to the mainbore trajectories, inversely. However, in the other two stress regimes, i.e. Strike Slip（SS） and Reverse Faulting（RF）, the variations of the mainbore and junction stability are in the same trend with respect to the mainbore trajectory deviations.

关键词： multidrain wells in-situ stresses NYZA mainbore lateral branches