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Oxygen vacancies enriched Ir/WOx catalysts for the directly chem-catalytic conversion of cellulose to ethanol

Tungsten 2025年第1期7卷 88-99页

作者： Yu-Jing Weng Zhao-Ying Ding Ying-Chao Li yuan-Feng Wu yuan-Yang xu Rui Chen Xiao-Lei Zhao Hai-Yong Wang Da-Lei Zhang Yu-Long Zhang Henan Key Laboratory of Coal Green Conversion and International Joint Laboratory of Coal Clean Utilization College of Chemistry and Chemical Engineering Henan Polytechnic University Key Laboratory of Renewable Energy Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Liaoning Institute of Energy Technology

Tungsten and its oxides are highly versatile catalysts with unique properties that hold great promise for a wide array of applications,including biological pathways and chemical *** chemo-catalysis of cellulose to ethanol presents a promising avenue for ethanol synthesis with the potential for enhanced efficiency compared to conventional methods,offering a sustainable and carbon-neutral alternative to existing petrochemical and biological ***,Ir/WOxcatalysts enriched with oxygen vacancies were meticulously prepared and demonstrated remarkable catalytic performance in converting cellulose to ethanol directly in the presence of tungstic *** catalyst achieved a high ethanol yield of 66.5%under optimal reaction conditions,approaching the theoretical yield limit of traditional ethanol *** results revealed the presence of oxygen defects,Bronsted/Lewis acidity,and Ir nanoclusters on the catalyst surface,working synergistically to facilitate the cascade catalysis of cellulose hydrolysis,sugar retro-aldol condensation reaction,and C2 intermediate hydrodeoxygenation to *** situ Fourier transform infrared spectrometer analysis confirmed the catalyst's ability to enhance the adsorption and activation of ethylene glycol for ethanol *** manipulating subtle structural features,this study offers a fresh perspective on tungsten group catalyst design and underscores the importance of synergistic effects among catalytic sites for the efficient production of ethanol from cellulose.

关键词： Cellulosic ethanol Chem-catalysis Hydrogenolysis Retro-aldol condensation Tungsten

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Negative Index Refraction in the Complex Ginzburg-Landau Equation in Connection with the Experimental CIMA Reaction

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Chinese Physics Letters 2012年第9期29卷 110-113页

作者： yuan xu-Jin Electromagnetic Scattering Key laboratory Beijing Institute of Environmental CharacteristicsBeijing 100854

In comparison with the phenomenon of negative index refraction observed in artificial meta-materials,it is interesting to ask if this type of behavior also exists or not in reaction-diffusion systems that support nonlinear chemical *** studies indicate that the negative index refraction could occur on a interface between a medium of a normal wave and a medium that supports *** we investigate the phenomenon in the complex Ginzburg–Landau equation(CGLE)in a close relationship with the quantitative model for the chlorite-iodide-malonic acid(CIMA)*** amplitude equation CGLE is deduced from the CIMA reaction,and simulations with mapped parameters from the reaction-diffusion equation reveal that the competition between normal waves and anti-waves on the interface determines whether the negative index refraction occurs or not.

关键词： reaction. refraction Landau

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Single-cell metagenomics： challenges and applications

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Protein & Cell 2018年第5期9卷 501-510页

作者： yuan xu Fangqing Zhao Computational Genomics Lab Beijing Institutes of Life Science Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China

With the development of high throughput sequencing and single-cell genomics technologies, many uncultured bacterial communities have been dissected by combining these two techniques. Especially, by simul- taneously leveraging of single-cell genomics and metagenomics, researchers can greatly improve the efficiency and accuracy of obtaining whole genome information from complex microbial communities, which not only allow us to identify microbes but also link function to species, identify subspecies variations, study host-virus interactions and etc. Here, we review recent developments and the challenges need to be addressed in single-cell metagenomics, including potential contamination, uneven sequence coverage, sequence chimera, genome assembly and annotation. With the development of sequencing and computational methods, single-cell metagenomics will undoubtedly broaden its application in various microbiome studies.

关键词： metagenomics bioinformatics single-celgenomics

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ACCELERATION METHODS OF NONLINEAR ITERATION FOR NONLINEAR PARABOLIC EQUATIONS

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Journal of Computational Mathematics 2006年第3期24卷 412-424页

作者： Guang-wei yuan xu-deng Hang Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P.O.Box 8009 Beijing 100088 China

This paper discusses the accelerating of nonlinear parabolic equations. Two iterative methods for solving the implicit scheme new nonlinear iterative methods named by the implicit-explicit quasi-Newton （IEQN） method and the derivative free implicit-explicit quasi-Newton （DFIEQN） method are introduced, in which the resulting linear equations from the linearization can preserve the parabolic characteristics of the original partial differential equations. It is proved that the iterative sequence of the iteration method can converge to the solution of the implicit scheme quadratically. Moreover, compared with the Jacobian Free Newton-Krylov （JFNK） method, the DFIEQN method has some advantages, e.g., its implementation is easy, and it gives a linear algebraic system with an explicit coefficient matrix, so that the linear （inner） iteration is not restricted to the Krylov method. Computational results by the IEQN, DFIEQN, JFNK and Picard iteration methods are presented in confirmation of the theory and comparison of the performance of these methods.

关键词： Nonlinear parabolic equations Difference scheme Newton iterative methods.

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Multivariate time delay analysis based local KPCA fault prognosis approach for nonlinear processes

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1413-1422页

作者： yuan xu Ying Liu Qunxiong Zhu College of Information Science and Technology Beijing University of Chemical Technology

Currently, some fault prognosis technology occasionally has relatively unsatisfied performance especially for in- cipient faults in nonlinear processes duo to their large time delay and complex internal connection. To overcome this deficiency, multivariate time delay analysis is incorporated into the high sensitive local kernel principal component analysis. In this approach, mutual information estimation and Bayesian information criterion （BIC） are separately used to acquire the correlation degree and time delay of the process variables. Moreover, in order to achieve prediction, time series prediction by back propagation （BP） network is applied whose input is multivar- iate correlated time series other than the original time series. Then the multivariate time delayed series and future values obtained by time series prediction are combined to construct the input of local kernel principal component analysis （LKPCA） model for incipient fault prognosis. The new method has been exemplified in a sim- ple nonlinear process and the complicated Tennessee Eastman （TE） benchmark process. The results indicate that the new method has suoerioritv in the fault prognosis sensitivity over other traditional fault prognosis methods.

关键词： Fault prognosis Time delay estimation Local kernel principal component analysis

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Squeeze flow of interstitial Herschel-Bulkley fluid between two rigid spheres

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Particuology 2010年第4期8卷 360-364页

作者： Chunhui xu Li yuan Yong xu Wenbin Hang College of Science China Agricultural University Beijing 100083 China

Interaction between two spheres with an interstitial fluid is crucial in discrete element modeling for simulating the behaviors of ＇wet＇ particulate materials. The normal viscous force of squeeze flow between two arbitrary rigid spheres with an interstitial HerscheI-Bulkley fluid was studied on the basis of Reynolds＇ lubrication theory, resulting in analytical integral expressions of pressure distribution and the viscous force between the two spheres. According to the variation of shear stress, the fluid was divided into yielding and unyielding regions, followed by a discussion on the thickness of the two regions. The result of this paper could be reduced to either the power-law fluid or the Bingham fluid case.

关键词： Wet granuleDiscrete element method Herschel-Bulldey fluid Viscous force

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Bifurcations of Exact Traveling Wave Solutions for(2+1)-Dimensional HNLS Equation

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Communications in Theoretical Physics 2012年第1期57卷 68-70页

作者： xu yuan-Fen Junior College Zhejiang Wanli UniversityNingbo 315101China

For the(2+1)-Dimensional HNLS equation,what are the dynamical behavior of its traveling wave solutions and how do they depend on the parameters of the systems? This paper will answer these questions by using the metho... 详细信息

关键词： planar dynamical system periodic wave solution solitary wave solution (2+1)-DimensionalHNLS equation

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Superconvergence Analysis of the Runge-Kutta Discontinuous Galerkin Method with Upwind-Biased Numerical Flux for Two-Dimensional Linear Hyperbolic Equation

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Communications on Applied Mathematics and Computation 2022年第1期4卷 319-352页

作者： yuan xu Qiang Zhang Department of Mathematics Nanjing UniversityNanjing 210093JiangsuChina

In this paper,we shall establish the superconvergence properties of the Runge-Kutta dis-continuous Galerkin method for solving two-dimensional linear constant hyperbolic equa-tion,where the upwind-biased numerical flux is *** suitably defining the correction function and deeply understanding the mechanisms when the spatial derivatives and the correction manipulations are carried out along the same or different directions,we obtain the superconvergence results on the node averages,the numerical fluxes,the cell averages,the solution and the spatial *** superconvergence properties in space are pre-served as the semi-discrete method,and time discretization solely produces an optimal order error in *** numerical experiments also are given.

关键词： Runge-Kutta discontinuous Galerkin method Upwind-biased flux Superconvergence analysis Hyperbolic equation Two dimensions

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Hydrologic Response to Future Climate Change in the Dulong-Irra-waddy River Basin Based on Coupled Model Intercomparison Project 6

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Chinese Geographical Science 2024年第2期34卷 294-310页

作者： xu Ziyue MA Kai yuan xu HE Daming Institute of International Rivers and Eco-security Yunnan UniversityKunming 650500China Yunnan Key Laboratory of International Rivers and Transboundary Eco-security Kunming 650500China

Within the context of the Belt and Road Initiative(BRI)and the China-Myanmar Economic Corridor(CMEC),the Dulong-Ir-rawaddy(Ayeyarwady)River,an international river among China,India and Myanmar,plays a significant role as both a valuable hydro-power resource and an essential ecological ***,the water resources and security exhibit a high degree of vulnerabil-ity to climate change *** research evaluates climate impacts on the hydrology of the Dulong-Irrawaddy River Basin(DIRB)by using a physical-based hydrologic *** crafted future climate scenarios using the three latest global climate models(GCMs)from Coupled Model Intercomparison Project 6(CMIP6)under two shared socioeconomic pathways(SSP2-4.5 and SSP5-8.5)for the near(2025-2049),mid(2050-2074),and far future(2075-2099).The regional model using MIKE SHE based on historical hydrologic processes was developed to further project future streamflow,demonstrating reliable performance in streamflow simulations with a val-idation Nash-Sutcliffe Efficiency(NSE)of *** showed that climate change projections showed increases in the annual precip-itation and potential evapotranspiration(PET),with precipitation increasing by 11.3%and 26.1%,and PET increasing by 3.2%and 4.9%,respectively,by the end of the century under SSP2-4.5 and *** changes are projected to result in increased annual streamflow at all stations,notably at the basin’s outlet(Pyay station)compared to the baseline period(with an increase of 16.1%and 37.0%at the end of the 21st century under SSP2-4.5 and SSP5-8.5,respectively).Seasonal analysis for Pyay station forecasts an in-crease in dry-season streamflow by 31.3%-48.9%and 22.5%-76.3%under SSP2-4.5 and SSP5-8.5,respectively,and an increase in wet-season streamflow by 5.8%-12.6%and 2.8%-33.3%,***,the magnitude and frequency of flood events are pre-dicted to escalate,potentially impacting hydropower production and food security *** res

关键词： climate change hydrologic response Coupled Model Intercomparison Project 6(CMIP6) MIKE SHE(Système Hydrologique Europeén) Dulong-Irrawaddy River Basin

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Distributed Kalman filter for UWB/INS integrated pedestrian localization under colored measurement noise

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Satellite Navigation 2021年第1期2卷 305-314页

作者： yuan xu Jing Cao Yuriy SShmaliy yuan Zhuang School of Electrical Engineering University of JinanJinanChina Department of Electronics Engineering Universidad de GuanajuatoSalamancaMexico State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Shandong Beiming Medical Technology Co. LtdJinanChina.

Colored Measurement Noise(CMN)has a great impact on the accuracy of human localization in indoor environments with Inertial Navigation System(INS)integrated with Ultra Wide Band(UWB).To mitigate its influence,a distributed Kalman Filter(dKF)is developed for Gauss-Markov CMN with switching Colouredness Factor Matrix(CFM).In the proposed scheme,a data fusion filter employs the difference between the INS-and UWB-based distance *** main filter produces a final optimal estimate of the human position by fusing the estimates from local *** effect of CMN is overcome by using measurement differencing of noisy *** tests show that the proposed dKF developed for CMN with CFM can reduce the localization error compared to the original dKF,and thus effectively improve the localization accuracy.

关键词： Distributed filtering Kalman filter Colored measurement noise Human localization

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