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highly Efficient and Stable hydrogen Production in All ph Range by Two-Dimensional Structured Metal-Doped Tungsten Semicarbides

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Research 2019年第1期2019卷 991-1004页

作者： Edison h.ang Khang N.Dinh Xiaoli Sun Ying h.ang Jun Yang Zhili Dong Xiaochen Dong Wei h.ang Zhiguo Wang hua Zhang Qingyu Yan Energy Research.institute Interdisciplinary Graduate SchoolNanyang Technological University637553Singapore Centre for Programmable Materials School of Materials Science and EngineeringNanyang Technological University639798Singapore institute of Advanced Materials Nanjing Tech UniversityNanjing 210000China School of Physical Electronics University of Electronic Science and Technology of ChinaChengdu 610054China Department of Chemistry City University of Hong KongKowloonHong Kong

Transition-metal-doped tungsten semicarbide nanosheets(M-doped W_(2)C NSs,M=Fe,Co,and Ni)have been synthesized through carburization of the mixture of tungsten trioxide,polyvinylpyrrolidone,and metal *** nanosheets grow directly on the W mesh and have the lateral dimension of several hundreds of nm to a few�m with a thickness of few tens *** is demonstrated that the M-doped W_(2)C NSs exhibit superior electrocatalytic activity for hydrogen evolution reaction(hER).impressively,the Nidoped W_(2)C NSs(2 at%Ni)with the optimized hER activity show extremely low onset overpotentials of 4,9,and 19 mV and modest Tafel slopes of 39,51,and 87 mV dec−1 in acidic(ph=0),neutral(ph=7.2),and basic(ph=14)solutions,respectively,which.is close to the commercial Pt/C *** functional theory(DFT)calculations also demonstrate that the Gibbs free energy for h adsorption of Ni-W_(2)C is much closer to the optimal valueG_(h∗)=-0.073 eV as compared to-0.16 eV of W_(2)***,nearly 100%Faradaic efciency and long-term stability are obtained in those *** realization of highly tolerant metal semicarbide catalyst performing on par with commercial Pt/C in all range of ph ofers a key step towards industrially electrochemical water splitting.

关键词： highly closer realization

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A micromechanical model based on hypersingular integro-differential equations for analyzing micro-crazed interfaces between dissimilar elastic materials

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Applied Mathematics and Mechanics(English Edition) 2020年第2期41卷 193-206页

作者： X.Wang W.T.ang h.FAN School of Mechanical and Aerospace Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

The current work models a weak(soft) interface between two elastic materials as containing a periodic array of micro-crazes. The boundary conditions on the interfacial micro-crazes are formulated in terms of a system of hypersingular integro-differential equations with unknown functions given by the displacement jumps across opposite faces of the micro-crazes. Once the displacement jumps are obtained by approximately solving the integro-differential equations, the effective stiffness of the micro-crazed interface can be readily computed. The effective stiffness is an important quantity needed for expressing the interfacial conditions in the spring-like macro-model of soft interfaces. Specific case studies are conducted to gain physical insights into how the effective stiffness of the interface may be influenced by the details of the interfacial micro-crazes.

关键词： micromechanical modeling micro-crazed interface effective stiffness coefficient hypersingular integro-differential equation

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Gradient Structured Copper by Rotationally Accelerated Shot Peening

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Journal of Materials Science & Technology 2017年第7期33卷 758-761页

作者： X.Wang Y.S.Li Q.Z.ang Y.h.Zhao Y.T.Zhu Nano Structural Materials Center School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing 210094 China Department of Materials Science and Engineering North Carolina State University Raleigh NC 27695 USA

A new technology-rotationally accelerated shot peening（RASP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RASP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RASP was utilized to refine the surface layer in pure copper（Cu） with an average grain size of 85 nm. The grain size increases largely from surface downwards the bulk, forming an800 ？m thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RASP technology and other established tech.iques in preparing gradient structured materials is discussed. The RASP technology exhibits a promoting future for large-scale manufacturing of gradient materials.

关键词： Microstructure Rotationally accelerated shot peening Gradient structure hardness Copper

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Validation of CFD-DEM simulation of a liquid-solid fluidized bed by dynamic analysis of time series

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Particuology 2022年第9期20卷 75-87页

作者： Julia Picabea Mauricio Maestri Miryan Cassanello Gabriel Salierno Cataldo De Blasio María angélica Cardona Daniel hojman héctor Somacal Departamento de industrias Facultad de Ciencias Exactas y NaturalesUniversidad de Buenos AiresCiudad UniversitariaIntendente Güiraldes 2160C1428EGABuenos AiresArgentina CONiCET-Universidad de Buenos Aires Instituto de Tecnología de Alimentos y Procesos Químicos-ITAPROQCiudad UniversitariaIntendente Güiraldes 2160 C1428EGABuenos AiresArgentina Faculty of Science and Engineering Abo Akademi UniversityRantakatu 265100 VaasaFinland Laboratorio de Diagnósticos por Radiaciones Dep.Física ExperimentalComisión Nacional de Energía AtómicaBKNA1650 San MartínBuenos AiresArgentina CONiCET C1033AAJ Buenos AiresArgentina Escuela de Ciencia y Tecnología Universidad de San MartínBKNA 1650 San MartínBuenos AiresArgentina

Liquid-solid fluidized beds(LSFB)modeling validation is crucial for establishing design rules and monitor-ing ***,it generally relies on comparing global variables,which overlook dynamic features that influence reaction *** work aims to implement time series analysis tools to compare Radioactive Particle Tracking data with a simulation consisting of Computational Fluid Dynamics cou-pled with Discrete-Element *** have been performed in a pilot-scale LSFB of calcium alginate spheres fluidized with a calcium chloride *** Diks'test indicates that the simulation can capture the LSFB *** also allows diagnosing flow regime transitions from the *** of solid dispersion coefficients and mixing times predicted by the simulation are in good agreement with the experiments.

关键词： Liquid-solid fluidization CFD-DEM Dynamic comparison Radioactive particle tracking

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Refining constitutive relation by integration of finite element simulations and Gleeble experiments

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Journal of Materials Science & Technology 2019年第6期35卷 1039-1043页

作者： D.J. Yu D.S. Xu h. W ang Z.B. Zhao G.Z. Wei R. Yang College of Sciences Northeastern University Shenyang 110004 China institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Thermo-mechanical coupled finite element calculations were carried out to simulate the Gleeble compression of the samples of a titanium alloy(Ti60), and the results are analyzed and compared with the actual compression tests conducted on a Gleeble 3800 thermo-mechanical simulator. The changes in temperature, stress and strain distribution in the samples and the source of error on the constitutive relations from Gleeble hot compression test were analyzed in detail. Both simulations and experiments showed that the temperature distribution in the specimen is not uniform during hot compression, resulting in significant deformation inhomogeneity and non-ignorable error in the flow stress strain relation,invalidating the uniform strain assumption commonly assumed when extracting the constitutive relation from Gleeble tests. Based on the finite element simulations with.iterative corrections, we propose a scheme to refine the constitutive relations from Gleeble tests.

关键词： Titanium alloy Constitutive relation Finite element Compression Temperature distribution

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Precise asymptotics in the law of the logarithm for random fields in hilbert space

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 651-659页

作者： FU Ke-ang Zhang Li-xin Department of Mathematics Zhejiang University Hangzhou 310027 China

Consider the positive d-dimensional lattice Z^d（d≥2） with partial ordering ≤, let {XK; K∈Z＋^d} be i.i.d, random variables taking values in a real separable hilbert space （h, ｜｜·｜｜） with mean zero and covariance operator ∑ and set partial sums SN =∑K≤nXK,K,N∈Z＋^d. Under some moment conditions, we obtain the precise asymptotics of a kind of weighted infinite series for partial sums SN as ε↓ by using the truncation and approximation methods. The results are related to the convergence rates of the law of the logarithm in hilbert space, and they also extend the results of （Gut and Spataru, 2003）.

关键词： The law of the logarithm Random field hilbert space. Tail probabilitv. Truncation method

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Precise Rates in the Law of the Logarithm for the Moment Convergence in hilbert Spaces

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Acta Mathematica Sinica,English Series 2009年第2期25卷 191-208页

作者： Ke ang FU Li Xin Zhang Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China School of Statistics and Mathematics Zhejiang Gongshang University Hangzhou 310035 P. R. China

Let （X, Xn; n ≥1） be a sequence of i.i.d, random variables taking values in a real separable hilbert space （h, ｜｜·｜｜） with covariance operator ∑. Set Sn = X1 ＋ X2 ＋ ... ＋ Xn, n≥ 1. We prove that, for b 〉 -1, lim ε→0 ε^2（b＋1） ∞ ∑n=1 （logn）^b/n^3/2 E{｜｜Sn｜｜-σε√nlogn}=σ^-2（b＋1）/（2b＋3）（b＋1） B｜｜Y｜^2b＋3holds if EX=0,and E｜｜X｜｜^2（log｜｜x｜｜）^3bv（b＋4）〈∞ where Y is a Gaussian random variable taking value in a real separable hilbert space with mean zero and covariance operator ∑, and σ^2 denotes the largest eigenvalue of ∑.

关键词： the law of the logarithm moment convergence tail probability strong approximation

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Development of a Compact Photoacoustic Tomography imaging System with Dual Single-Element Transducers for image Enhancement

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Current Medical Science 2021年第6期41卷 1151-1157页

作者： Yong-jian ZhAO Xiao-long ZhU Pei-yu LUO ang Li Wei XiAO Xiao XiAO Li LiU Max Q.-h.MENG Department of Electronic and Electrical Engineering the Southern University of Science and TechnologyShenzhen 518055China Department of Electronic Engineering The Chinese University of Hong KongHong Kong 999077China Shenzhen Research.institute of The Chinese University of hong Kong in Shenzhen Shenzhen 518172China

Objective:This paper proposes a new photoacoustic computed tomography(PACT)imaging system employing dual ultrasonic transducers with different *** imaging complex biological tissues,photoacoustic(PA)signals with multiple frequencies are produced simultaneously;however,due to the limited bandwidth of a single-frequency transducer,the received PA signals with specific frequencies may be missing,leading to a low imaging ***:in contrast to our previous work,the proposed system has a compact volume as well as specific selection of the detection center frequency of the transducer,which can provide a comprehensive range for the detection of PA *** this study,a series of numerical simulation and phantom experiments were performed to validate the efficacy of the developed PACT ***:The images generated by our system combined the advantages of both high resolution and ideal brightness/***:The interchangeability of transducers with different frequencies provides potential for clinical deployment under the circumstance where a single frequency transducer cannot perform well.

关键词： photoacoustic tomography dual transducers image enhancement signal responding range

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Contributions of adsorption, bioreduction and desorption to uranium immobilization by extracellular polymeric substances

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Frontiers of Environmental Science & Engineering 2023年第9期17卷 125-135页

作者： Chen Zhou Ermias Gebrekrstos Tesfamariam Youneng Tang ang Li Biodesign Swette Center for Environmental Biotechnology Arizona State UniversityTempeAZ 85281USA Department of Civil and Environmental Engineering FAMU-FSU College of EngineeringFlorida State UniversityTallahasseeFL 32310USA State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

hexavalent uranium(U(Vi))can be immobilized by various *** role of extracellular polymeric substances(EPS)in U(Vi)immobilization has not been *** work provides a model framework to quantify the contributions of three processes involved in EPS-mediated U(Vi)immobilization:adsorption,bioreduction and *** associated EPS was extracted from a pure bacterial strain,Klebsiella sp.J1,and then exposed to h_(2) and O_(2)(no bioreduction control)to immobilize U(Vi)in batch experiments.U(Vi)immobilization was faster when exposed to h_(2) than O_(2) and stabilized at 94%for h_(2) and 85%for O_(2),*** non-equilibrium data from the h_(2) experiments were best simulated by a kinetic model consisting of pseudo-second-order adsorption(ka=2.87×10^(−3) g EPS·(mg U)^(−1)·min^(−1)),first-order bioreduction(kb=0.112 min−1)and first-order desorption(kd=7.00×10^(−3) min^(−1))and fitted the experimental data with R^(2) of *** adsorption was dominant in the first minute of the experiments with h_(2),bioreduction was dominant from the second minute to the 50th *** 50 min,adsorption was negligible,and bioreduction was balanced by *** work also provides the first set of equilibrium data for U(Vi)adsorption by EPS *** equilibrium experiments with O_(2) were well simulated by both the Langmuir isotherm and the Freundlich.isotherm,suggesting multiple mechanisms involved in the interactions between U(Vi)and *** thermodynamic study indicated that the adsorption of U(Vi)onto EPS was endothermic,spontaneous and favorable at higher temperatures.

关键词： Adsorption Bioreduction Desorption Kinetics isotherm Uranium

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大型基础设施系统设计中的风险及概率(英文)

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重庆交通大学学报（自然科学版） 2011年第A2期30卷 1084-1089,1232页

作者： A.h-S.ang 加利福尼亚大学埃文校区美国加利福尼亚

在大型基础设施系统中,不可避免地会出现重大的不确定性,因而,无法确保已建系统的安全性和可靠性。有功能失效甚至破坏的可能,同时也有相应的规避风险的措施。从实用角度出发,不确定性可以分为两大类:数据型(又称偶然型)不确定性和知识... 详细信息

在大型基础设施系统中,不可避免地会出现重大的不确定性,因而,无法确保已建系统的安全性和可靠性。有功能失效甚至破坏的可能,同时也有相应的规避风险的措施。从实用角度出发,不确定性可以分为两大类:数据型(又称偶然型)不确定性和知识型(又称认知型)不确定性。前者可以通过对数据的观察来评估,而后者则需要主观判断。系统地分析了这两类不确定性,得到有关风险预测的信息,为大型基础设施设计提供基于安全(即规避风险)的建议;对在地震荷载下大型基础设施进行了安全设计;以韩国某斜拉桥为例,对其进行了数值化评估及最低生命周期成本设计。

关键词：风险概率不确定性安全性可靠性基础设施桥梁设计

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