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Science China Chemistry 2020年第6期63卷 850-859页

作者： yu mao P.Hu School of Chemistry and Chemical Engineering The Queen’s University of BelfastBelfastUK

To make methane a suitable energy carrier and transport less costly,it is an urgent and challenging task for us to convert methane to liquid under mild conditions *** this study,we explored partial methane oxidation to methanol by density functional theory(DFT)calculations using a hybrid functional(HSE06)with van der Waals(vdW)*** stabilities of different active sites over SSZ-13 and SAPO-34,two CHA type zeolites,are thoroughly investigated by ab initio molecular dynamics(AIMD)simulations and ab initio thermodynamics *** possible active sites,namely[CuOHCu]2+,[Cu(OH)2Cu]2+,[CuOCu]2+and[CuOH]+,are identified ***-to-methanol reaction mechanisms are further studied upon these most stable active sites,among which[CuOCu]2+and[CuOH]+are proved to be *** migration of species among zeolite pores are also discussed,which accounts for the activity on[CuOH]+*** concept may represent a more complete picture of catalytic reactions over zeolites in general.

关键词： DFT heterogeneous catalysis methane-to-methanol CHA zeolites

Prioritizing chemicals for environmental management in China based on screening of potential risks

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Frontiers of Earth Science 2014年第1期8卷 104-114页

作者： Xiangyi yu Yan mao Chemical Registration Center of Ministry of Environmental Protection Beijing 100012 China

The rapid development of China＇s chemical industry has created increasing pressure to improve the environmental management of chemicals. To bridge the large gap between the use and safe management of chemicals, we performed a comprehensive review of the international methods used to prioritize chemicals for environmental management. By comparing domestic and foreign methods, we confirmed the presence of this gap and identified potential solutions. Based on our literature review, we developed an appropriate screening method that accounts for the unique characteristics of chemical use within China. The proposed method is based on an evaluation using nine indices of the potential hazard posed by a chemical： three environmental hazard indices （persistence, bioaccumulation, and eco-toxicity）, four health hazard indices （acute toxicity, carcinogenicity, mutagenicity, and reproductive and developmental toxi- city）, and two environmental exposure hazard indices （chemical amount and utilization pattern）. The results of our screening agree with results of previous efforts from around the world, confirming the validity of the new system. The classification method will help decision- makers to prioritize and identify the chemicals with the highest environmental risk, thereby providing a basis for improving chemical management in China.

关键词： chemicals screening risk environmental management priority definition

Achieving accuracy and efficiency at the same time: a new kinetic Monte Carlo approach for complicated catalytic systems

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Science China Chemistry 2018年第12期61卷 1479-1480页

作者： yu mao P.Hu School of Chemistry and Chemical Engineering The Queen's University of Belfast

Rational design/screening of more active,more selective,and less expensive catalysts has long been an important target in heterogeneous catalysis [1].In recent decades,the advances of density functional theory (DFT)calculations allow us to theoretically evaluate the activity of *** shown in Figure 1(a),kinetics serves as the link between the atomic-scale properties obtained by DFT and turnover frequency (TOF)of catalysts.

关键词： Achieving accuracy efficiency kinetic Monte Carlo complicated catalytic systems

Non-Fourier heat conduction in a thin gold film heated by an ultra-fast-laser

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Science China(Technological Sciences) 2015年第4期58卷 638-649页

作者： mao yu Dong XU Ming Tian Department of Engineering Mechanics School of Civil Engineering Shandong University School of Energy and Power Engineering Shandong University

Based on the dual-phase-lagging(DPL)heat conduction model,the Cattaneo-Vernotte(CV)model and the improved CV model we investigate the one-dimensional heat conduction in gold films with nano-scale thickness exposed to an ultra-fast laser *** influence of system parameters on the temperature field is *** find that for all the non-Fourier heat conduction models considered in this work,a larger Knudsen number normally leads to a higher *** the DPL model,the large ratio of the phase lag of temperature gradient to the phase lag of heat flux reduces the maximum temperature and shortens the time for the system to reach its steady *** CV model and the improved CV model lead to the similar thermal wave behavior of the temperature field,but the thermal wave speeds for these two models are different,especially for large Knudsen *** the phase lag of temperature gradient is smaller,the difference between the DPL model and the improved CV model is not significant,but for the large phase lag of temperature gradient the difference becomes quite significant,especially for the large Knudsen *** addition,the effect of the surface accommodation coefficient,which is a parameter in the slip boundary condition,on the temperature field of the gold film heated by ultra-fast laser pulses is investigated based on the DPL model.

关键词： Nano-scale heat conduction ultrafast laser heating thin film Knudsen number

Hybrid ionic thermoelectric and photocatalytic materials(i-TEPC):a new choice for energy harvesting

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Science China Chemistry 2024年第7期67卷 2127-2129页

作者： Qikai Li mao yu Weishu Liu Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

Ionic thermoelectric(i-TE)material is a kind of new functional material that can convert heat energy into electric energy,which is of great significance for renewable energy technologies and sustainable development[1].The fundamental constitution of i-TE material mainly comprises an electrolyte matrix,ion providers and redox pairs.

关键词： energy harvesting convert

Adaptive Local Linear Quantile Regression

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Acta Mathematicae Applicatae Sinica 2011年第3期27卷 509-516页

作者： yu-nan Su mao-zai Tian Center for Applied Statistics School of Statistics Remin University of China Beijing 100872 China

In this paper we propose a new method of local linear adaptive smoothing for nonparametric conditional quantile regression. Some theoretical properties of the procedure are investigated. Then we demonstrate the performance of the method on a simulated example and compare it with other methods. The simulation results demonstrate a reasonable performance of our method proposed especially in situations when the underlying image is piecewise linear or can be approximated by such images. Generally speaking, our method outperforms most other existing methods in the sense of the mean square estimation （MSE） and mean absolute estimation （MAE） criteria. The procedure is very stable with respect to increasing noise level and the algorithm can be easily applied to higher dimensional situations.

关键词： quantile regression local linear regression adaptive smoothing automatic choice of window size Robustness

Hydraulic resistance of river ice jams

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Journal of Hydrodynamics 2019年第3期31卷 504-511页

作者： Lin Fan Ze-yu mao Hung Tao Shen Department of Hydraulic Engineering Tsinghua University Beijing 100084 China Development Research Center of the Ministry of Water Resources Beijing 100036 China Department of Civil and Environmental Engineering Clarkson University Potsdam NY 13676 USA

The hydraulic resistance of the river ice jams consists of the resistances due to the seepage flow through the jam and the shear stress on the undersurface of the jam. Existing empirical formulations consider only the the undersurface resistance of the jam, and come up with relations between the jam resistance and the jam thickness with very slight theoretical basis. Based on the analysis of the seepage flow resistance and the flow resistance of the undersurface of the jam, it is shown that the resistance due to the seepage flow is a dominating part of the jam resistance, except for the portion of the jam where the thickness is very small. This analysis also shows that the total jam resistance can be approximated by a linear function of the jam thickness or the ratio of the jam thickness to the flow depth under the jam.

关键词： River ice hydraulic resistance ice jam friction factor Manning's coefficient

A novel machine learning approach(svm Somatic) to distinguish somatic and germline mutations using next-generation sequencing data

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Zoological Research 2021年第2期42卷 246-249页

作者： yu-Fang mao Xi-Guo yuan yu-Peng Cun School of Computer Science and Technology Xidian UniversityXi'anShaanxi 710071China iFlora Bioinformatics Center Germplasm Bank of Wild SpeciesKunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China

DEAR EDITOR,Somatic mutations are a large category of genetic variations,which play an essential role in tumorigenesis. Detection of somatic single nucleotide variants(SNVs) could facilitate downstream analysis of tumorigenesis. Many computational methods have been developed to detect SNVs, but most require normal matched samples to differentiate somatic SNVs from the normal state, which can be difficult to obtain.

关键词： data A novel machine learning approach svm Somatic

An improvement to the simulation of phase-change heat-transfer during soil freezing and thawing

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Mining Science and Technology 2009年第2期19卷 262-268页

作者： YANG Tao ZHENG mao-yu School of Municipal and Environment Harbin Institute of Technology Harbin Heilongjiang 150090 China

A new variable time step method,which is called the backwards calculating time step method,is presented in this *** allows numerical simulation of soil freezing and thawing while avoiding "phase change missing and overflowing".A sensitive heat capacity model is introduced through which the calculation errors are *** the equation using the self-adjusted time step is presented and solved using finite *** this equation,the time needed for a space cell to reach the phase change point temperature is *** this time allows the time step to be adjusted so that errors caused by "phase change missing and overflowing" are successfully *** all,the obvious features of this method are an accelerated rate for adjusting the time step and simplifing the *** actual example proves that this method can accurately calculate the temperature fields during soil freezing and *** is an improvement over traditional methods and can be widely used on complicated multi-dimensional phase change problems.

关键词： backwards calculating time step method phase change missing phase change overflowing

Scalable Preparation of SrTiO_3 Submicro-wires from Layered Titanate Nanowires

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Chinese Journal of Aeronautics 2007年第2期20卷 177-180页

作者： TANG mao-yu JI Tian-hao XIE Jian School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

SrTiO3 submicro-wires were prepared by the reaction of layered titanatc nanowircs with Sr（OH）2 powder in an autoclave. The wires were investigated using X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM）, Ultra-violet visible （UV-vis）, photoluminescence （PL） and Raman spectroscopy. The XRD measurement shows that the prepared SrTiO3 submicro-wircs hardly have impurity phases. The SEM and TEM images demonstrate that the scalable wires, which need to be processed at the reaction temperature of 180℃ for about 48 hours, are not composed of single crystals. The PL shows that the wire-like SrTiO3 has emission peaks at the wavelengths of 568 and 585 nm. Further, the Raman spectroscopy reveals structural changes in the products through different reaction time.

关键词： oxide titanate nanowires strontium titanate SrTiO3 wires