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PM2.5 over North china based on MODIS AOD and effect of meteorological elements during 2003-2015

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Frontiers of environmental Sc.ence & engineering 2020年第2期14卷 27-40页

作者： Youfang c.en yimin Zhou Xinyi Zhao college of Urban and environmental Sc.ences Peking UniversityBeijing 100871China Key Laboratory for earth Surface Processes of the Ministry of education Peking UniversityBeijing 100871China

Over the past 40 years,PM2.5 pollution in North china has become inc.easingly serious and progressively exposes the densely populated areas to ***,due to limited ground data,it is challenging to estimate accurate PM2.5 exposure levels,further making it unfavorable for the prediction and prevention of PM2.5 *** paper therefore uses the mixed effect model to estimate daily PM2.5 concentrations of North china between 2003 and 2015 with ground observation data and MODIS AOD satellite *** tempo-spatial charac.eristics of PM2.s and the influence of meteorological elements on PM25 is discussed with eOF and canonical correlation analysis *** show that overall R2 is 0.36 and the root mean squared predic.ed error was 30.1μg/m^3 for the model *** time series analysis showed that,the Taihang Mountains ac.ed as a boundary between the high and low pollution areas in North china;while the northern part of Henan Province,the southern part of Hebei Province and the western part of Shandong Province were the most polluted ***,in 2004,2009 and dates after 2013,PM25 concentrations were relatively ***/topography conditions,that include high surface humidity of area in the range of 34°-40°N and 119°-124°e,relatively low boundary layer heights,and southerly and easterly winds from the east and north area were common factors attributed to haze in the most polluted ***,the spatial distribution of inc.easingly concentrated PM2.5 pollution in North china are consistent with the local emission level,unfavorable meteorological conditions and topographic changes.

关键词： Aerosol optical depth PM2.5 MODIS Mixed effect model canonical correlation analysis

Synergetic strengthening mechanism of ultrasound combined with calcium fluoride towards vanadium extraction from low-grade vanadium-bearing shale

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International Journal of Mining Sc.ence and Technology 2021年第6期31卷 1095-1106页

作者： Bo c.en Shenxu Bao yimin Zhang School of Resources and environmental engineering Wuhan University of TechnologyWuhan 430070China Hubei Key Laboratory of Mineral Resources Processing and environment Wuhan 430070China State environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution control Wuhan University of Science and TechnologyWuhan 430081China Hubei collaborative Innovation center for High effic.ent Utilization of Vanadium Resources Wuhan University of Science and TechnologyWuhan 430081China

The effect and mechanism of ultrasound and caF_(2) on vanadium leaching from vanadium-bearing shale were investigated *** consideration of the enhancement for vanadium recovery,the combination of ultrasound and caF_(2)(66.28%) exerts more evident effects than ultrasound(26.97%) and caF_(2)(60.35%) alone,demonstrating the synergetic.effect of ultrasound and caF_(2).Kinetic analysis manifests that the product layer diffusion controls vanadium leaching in ultrasound system without caF_(2),however product layer diffusion and interfacial reaction is the rate-controlling step for vanadium leaching in other three leaching *** combination of ultrasound and caF_(2) notably dec.eases the activation energy(e_(a)) from 62.03 to 27.61 kJ/mol,nevertheless individual caF_(2) only reduces the e_(a) to 50.70 kj/mol.X-ray diffraction and fourier transform infrared spectrometer analyses show that the decomposition degree of the vanadium-bearing mica structure is the most significant in ultrasound and caF_(2) system,proving the highest release degree of *** surface area and pore distribution combined with scanning electron microscope analyses reveal that the action of ultrasound and caF_(2) would provide higher specific surface area,more abundant pores structure and cracks for the partic.es,which further prompts the rapid diffusion of H^(+),F^(-)and HF,and achieves the conspicuous improvement of vanadium leaching recovery.

关键词： Vanadium-bearing shale Ultrasound caF_(2)addition Synergetic.effect Leaching kinetics

AN INTeGRO-DIFFeReNTIAL PARABOLIc VARIATIONAL INeQUALITY ARISING FROM THe VALUATION OF DOUBLe BARRIeR AMeRIcAN OPTION

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Journal of Systems Sc.ence & complexity 2014年第2期27卷 276-288页

作者： SUN Yudong SHI yimin GU Xin Department of Applied Mathematics Northwestern Polytechnical University Department of Methodology and Statistics Utrecht University

This paper studies the nonlinear variational inequality with integro-differential term arising from valuation of American style double barrier option. First, the authors use the penalty method to transform the variational inequality into a nonlinear parabolic initial boundary problem(i.e., penalty problem). Second, the existence and uniqueness of solution to the penalty problem are proved by using the Sc.eafer fixed point theory. Third, the authors prove the existence of variational inequality' solution by showing the fact that the penalized PDe converges to the variational inequality. The uniqueness of solution to the variational inequality is also proved by contradiction.

关键词： American style barrier option existence integro-differential uniqueness variational inequality.

e-Bayesian estimation for competing risk model under progressively hybrid censoring

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Journal of Systems engineering and electronics 2016年第4期27卷 936-944页

作者： Min Wu yimin Shi Yan Wang Department of Applied Mathematics Northwestern Polytechnical University

This paper considers the Bayesian and expec.ed Bayesian（e-Bayesian） estimations of the parameter and reliability function for competing risk model from Gompertz distribution under Type-I progressively hybrid censoring sc.eme（PHcS）. The estimations are obtained based on Gamma conjugate prior for the parameter under squared error（Se） and Linex loss functions. The simulation results are provided for the comparison purpose and one data set is analyzed.

关键词： Bayesian estimation expec.ed Bayesian(e-Bayesian) estimation Gompertz distribution Type-I progressively hybrid censoring

On intersections of independent anisotropic Gaussian random fields

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Sc.ence china Mathematics 2012年第11期55卷 2217-2232页

作者： c.eN ZhenLong XIAO yimin School of Statistics and Mathematics Zhejiang Gongshang UniversityHangzhou 310018China Department of Statistics and Probability Michigan State UniversityEast Lansing:MI 48824USA

Let X^H = {X^H（8）,8∈ R^N1} and XK = {X^K（t）,t ∈R^2} be two independent anisotropic Gaussian random fields with values in R^d with indices H = （H1,... ,HN1） ∈ （0, 1）^N1, K = （K1,..., KN2）∈ （0, 1）^N2, respectively. existence of intersections of the sample paths of XH and XK is studied. More generally, let e1 R^N1, e2 R^N2 and F R^d be Borel sets. A necessary condition and a suffic.ent condition for P{（X^H（e1） ∩ X^K（e2）） ∩ F ≠ Ф} 〉 0 in terms of the Bessel-Riesz type capacity and Hausdorff measure of e1 x e2 x F in the metric space （R^N1＋N2＋d, ρ） are proved, whereρ is a metric defined in terms of H and K. These results are applicable to solutions of stochastic heat equations driven by space-time Gaussian noise and fractional Brownian sheets.

关键词： intersection anisotropic Gaussian fields hitting probability Hausdorff dimension stochastic heatequation fractional Brownian sheet

An insight on the mechanism of effic.ent leaching of vanadium from vanadium shale induced by microwave-generated hot spots

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International Journal of Minerals,Metallurgy and Materials 2023年第2期30卷 293-302页

作者： Sheng Li yimin Zhang Yizhong Yuan Pengc.eng Hu School of Resource and environmental engineering Wuhan University of Science and TechnologyWuhan 430081China State environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution control Wuhan University of Science and TechnologyWuhan 430081China collaborative Innovation center of Strategic Vanadium Resources Utilization Wuhan 430081China Hubei Provincial engineering Technology Research center of High effic.ent c.eaning Utilization for Shale Vanadium Resource Wuhan University of Science and TechnologyWuhan 430081China School of Resource and environmental engineering Wuhan University of TechnologyWuhan 430070China

Microwave heating can rapidly and uniformly raise the temperature and ac.elerate the reaction *** this paper,microwave heating was used to improve the acid leaching,and the mechanism was investigated via microscopic morphology analysis and numerical simulation by cOMSOL Multiphysics *** effects of the microwave power,leaching temperature,caF_(2) dosage,H_(2)SO_(4) concentration,and leaching time on the vanadium recovery were investigated.A vanadium recovery of 80.66%is obtained at a microwave power of 550 W,leaching temperature of 95℃,caF_(2) dosage of 5wt%,H_(2)SO_(4) concentration of 20vol%,and leaching time of 2.5 *** with conventional leaching technology,the vanadium recovery inc.eases by 6.18%,and the leaching time shortens by 79.17%.More obvious pulverization of shale partic.es and delamination of mica minerals happen in the microwave-assisted leaching *** simulation results show that the temperature of vanadium shales inc.eases with an inc.ease in electric field(e-field).The distributions of e-field and temperature among vanadium shale partic.es are relatively uniform,except for the higher content at the contact position of the *** analysis results of scaleup experiments and leaching experiments indicate high-temperature hot spots in the process of microwave-assisted leaching,and the local high temperature destroys the mineral structure and ac.elerates the reaction rate.

关键词： vanadium shale microwave-assisted leaching hot spots numerical simulation

experimental and MD simulation of 3-dodecyloxypropanamine and 3-tetradecyloxypropylamine adsorbed onto quartz(101) surface

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International Journal of Mining Sc.ence and Technology 2021年第6期31卷 1033-1042页

作者： Zhouyueyang c.eng yimin Zhu Yanjun Li Stephen Butt a college of Resource and civil engineering Northeastern UniversityShenyang 110819China b National-Local Joint engineering Research center of Refractory Iron Ore Resources effic.ent Utilization Technology Shenyang 110819China c Faculty of engineering and Applied Sc.ence Memorial University of NewfoundlandSt.John’s A1C 5S7Canada

In this paper,two surfactants,3-dodecyloxypropanamine(DOPA) and 3-tetradecyloxypropylamine(TOPA),were synthesized and used as collectors in the quartz micro-flotation in the *** tests,FT-IR,XPS measurements,and ab initio Molecular Dynamics(MD) simulations were conduc.ed to research DOPA,TOPA,and dodecylamine(DDA)'s adsorption mechanisms onto quartz(101)*** results of micro-flotation show that the adsorption of DOPA and TOPA onto quartz surface is more robust than that of *** zeta-potential result shows that the DOPA/TOPA was adsorbed on quartz through electrostatic ***,MD simulation adsorption models were built to compare the computational properties of the three surfactants,such as the radial distribution function,and the interaction energies between the collectors and the quartz c.eavage *** interaction energies of surfactants(RNH_(3)^(+) or RNH_(2)) on the quartz surface explained why the pH range of DOPA/TOPA is wider than that of *** analyses and MD simulations confirmed that DOPA bonded with the(101) surface of quartz through three types of hydrogen bonds between the-NH_(2) of DOPA and the O atom of *** hydrogen bonds of type A and type c were the most likely type and more potent than those of type B.

关键词： Quartz(101)surface Flotation Molecular dynamics 3-Dodecyloxypropanamine Adsorption

Investigation on emissive properties of peroskite-type oxide LSMO with grating surface

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Sc.ence china(Technological Sc.ences) 2011年第1期54卷 220-225页

作者： HUANG JinGuo XUAN yimin LI Qiang School of Power engineering Nanjing University of Science & Technology Nanjing 210094 China

This paper aims to investigate thermal radiative charac.eristics of thermochrornic material La0.825Sr0.175MnO3（LSMO） with one-dimensional grating structured surfaces. The dielectric function of LSMO was calculated by K-K approach. Numerical calculation was conduc.ed to obtain spectral emittance distribution of such surfaces with different structural parameters using the finite difference time domain （FDTD） method. It was found that the spectral emittance of LSMO structured surface exhib- ited the feature of selective enhancement due to the excitation of microcavity effect. The effects of structural parameters on spectral emittance indicated that the desired radiative enhancement could be achieved by the rational design of the structural parameters of grating. The temperature dependence of averaged emittance of LSMO was also calculated, The results showed that LSMO with grating structured surface had a better thermochromic performance compared with LSMO with smooth surface.

关键词： grating thermochromic materials emission

Splitting Method for Support Vector Machine in Reproducing Kernel Banach Space with a Lower Semi-continuous Loss Function

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chinese Annals of Mathematics,Series B 2024年第6期45卷 823-854页

作者： Mingyu MO yimin WeI Qi Ye Academy for Advanced Interdisciplinary Studies Peking University School of Mathematical Sc.ence South China Normal University School of Mathematical Sc.ence Key Laboratory of Mathematics for Nonlinear Sciences Fudan University corresponding author.School of Mathematical Sc.ence South China Normal University

In this paper, the authors employ the splitting method to address support vector machine within a reproducing kernel Banach space framework, where a lower semicontinuous loss function is utilized. They translate support vector machine in reproducing kernel Banach space with such a loss function to a finite-dimensional tensor optimization problem and propose a splitting method based on the alternating direction method of multipliers. Leveraging Kurdyka-Lojasiewicz property of the augmented Lagrangian function,the authors demonstrate that the sequence derived from this splitting method is globally convergent to a stationary point if the loss function is lower semi-continuous and subanalytic. Through several numerical examples, they illustrate the effectiveness of the proposed splitting algorithm.

关键词： 46e22 68P01 68Q32 68T05 Lower semi-continuous loss function Reproducing kernel Banach space Splitting method Support vector machine Tensor optimization problem