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LEAST-SQUARES GALERKIN PROCEDURE FOR SECOND-ORDER HYPERBOLIC EQUATIONS

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Journal of Systems Science & Complexity 2011年第2期24卷 381-393页

作者： hui guo Hongxing RUI Chao LIN School of Mathematics and Computational Science China University of Petroleum Dongying 257061 China. School of Mathematics and System Science Shandong University Jinan 250100 China. Network and Education Technology Center China University of Petroleum Dongying 257061 China.

This paper proposes the least-squares Galerkin finite dement scheme to solve secona-oraer hyperbolic equations. The convergence analysis shows that the method yields the approximate solutions with optimal accuracy in （L2 （Ω））2 × L2 （Ω） norms. Moreover, the method gets the approximate solutions with second-order accuracy in time increment. A numerical example testifies the efficiency of the novel scheme. Key words Convergence analysis, Galerkin finite element, hyperbolic equations, least-squares, nu- merical example.

关键词： Convergence analysis Galerkin finite element hyperbolic equations least-squares nu-merical example.

Elution of 17α 25-Norhopanes and Triaromatic Steroids from Weathered Soils by Mixed Triton X-100/Na_2SiO_3 Surfactant Solution

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Chemical Research in Chinese Universities 2012年第3期28卷 419-423页

作者： JI guo-dong ZHOU guo-hui Key Laboratory of Water and Sediment Sciences Ministry of EducationDepartment of Environmental EngineeringPeking UniversityBeo'ing 100871P.R.China

Sodium silicate（NazSiO3） was used to improve the elution of super heavy oil from weathered soil on an ultrasound-enhanced elution system by the solution containing 0-6000 mg/L surfactant Triton X-100. The removal extent of three markers[C26-34 17a 25-norhopanes, C26-28triaromatic steroids（TAS）, and C27-29methyl triaromatic steroids（MTAS）] was monitored. The average elution percentages of C26-34 norhopanes, C26-28 TAS, and C27-29 MTAS by Triton X-100/Na2SiO3 solutions were increased by 11%-13%, 9%-11% and 8%-13% with increasing Triton X-100 concentrations from 150 mg/L to 6000 mg/L. All the concentrations of Triton X-100 improved the elu- tion of TAS homologs containing fewer carbon atoms, whereas high concentrations improved the elution of larger 17a 25-norhopane and MTAS species. Addition of Na2SiO3 produced a noticeable increase in elution, particularly for lower-weight species. Scanning electron microscope（SEM） images and energy spectroscopy data reveal that surfac- rant solution of 6000 mg/L Triton X-100 and 4000 mg/L Na2SiO3 produced the greatest improvement in the elution of super heavy oil aggregates encapsulating the soil surface and the emulsification of particle dispersions. That is to say mixed solutions of Triton X-100 and Na2SiO3 in combination with ultrasound are a potential means of removing super heavy oil from weathered soils.

关键词： Triton X-100 surfactant solution Na2SiO3 17a 25-Norhopane Triaromatic steroid Biomarker

A case study of gas drainage to low permeability coal seam

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International Journal of Mining Science and Technology 2017年第4期27卷 687-692页

作者： Zhang Li Zhang hui guo Hao China Coal Strategies Research Center & China Center for Occupational Safety and Health Beijing 100713 China Institute of Public Safety Research/Department of Engineering Physics Tsinghua University Beijing 100084 China College of Resource and Safety Engineering China University of Mining & Technology Beijing 100083 China

Gas drainage at low gas permeability coal seam is a main barrier affecting safety and efficient production in coal mines. Therefore, the research and application of drainage technology at low permeability coal seam is a key factor for gas control of coal mine. In order to improve the drainage effect, this paper establishes a three-dimensional solid-gas-liquid coupling numerical model, and the gas drainage amounts of different schemes are examined inside the overburden material around the goaf. The Yangquan mine area is selected for the case study, and the gas movement regularity and emission characteristics are analyzed in detail, as well as the stress and fissure variation regularity. Also examinations are the released gas movement, enrichment range and movement regularity during coal extraction. Moreover, the gas drainage technology and drainage parameters for the current coal seam are studied. After measuring the gas drainage flow in-situ, it is concluded that the technology can achieve notable drainage results, with gas drainage rate increase by 30%–40% in a low permeability coal seam.

关键词： Gas drainage Low permeability Ground drilling holes Coupling model Abutment stress

Energy-Efficient coaromatization of methane and propane

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Journal of Natural Gas Chemistry 2009年第3期18卷 260-272页

作者： Jianjun guo hui Lou Xiaoming Zheng Institute of Catalysis Zhejiang University Hangzhou 310028 Zhejiang China Division of Functional Materials and Nano Devices Ningbo Institute of Material Technology and Engineering Chinese Academy of Sciences Ningbo 315201 Zhejiang China

Development of highly effective catalysts for one-stage conversion of methane with high selectivity to valuable products and energy efficiency will provide an efficient way to utilize natural gas and oil-associated gases and to protect environment. In recent years, there have been many efforts on direct catalytic transformations of methane into higher hydrocarbons by feeding additives together with methane under non-oxidative conditions. This paper reviewed the advances in recent research on non-oxidative aromatization of methane in the presence of propane over different modified HZSM-5 catalysts. The thermodynamic consideration, the isotope verification and the mechanism of the activation of methane in the presence of propane are discussed in the paper in detail.

关键词： methane propane non-oxidative aromatization

In situ anchoring in carbon matrix of Bi_(2)O_(2)CO_(3) as a high-performance anode material for Li-ion batteries

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Rare Metals 2024年第8期43卷 3634-3646页

作者： Pu-Qiang He Jun guo hui Huang Zhong-Cheng guo Faculty of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China Research Center of Metallurgical Electrode Materials Engineering Technology Kunming 650106China Kunming Hendera Science and Technology Co. Ltd.Kunming 650106China

Bismuth-based anode materials have been regarded as promising Li-ion batteries due to their high theoretical ***,their low conductivity and associated volume expansion inhabited their *** this work,Bi_(2)O_(2)CO_(3)@C composites were successfully synthesized by in situ anchoring of flower-like Bi_(2)O_(2)CO_(3) nanosheets on a carbon-based substrate via *** unique composited structure of Bi_2O_(2)-CO_(3)@C leads to a stable specific capacity of 547 mAh·g^(-1)after 100 cycles at a current density of 0.1 A·g^(-1).Notably,it demonstrates excellent rate capability with a specific capacity of 210 mAh·g^(-1)at 5 A·g^(-1).After 550 cycles at a current density of 0.5 A·g^(-1),a high reversible capacity of nearly 400 mAh·g^(-1)was ***,in situ X-ray diffraction measurements clearly demonstrate the conversion between Bi and Li_(3)Bi during alloying/dealloying,confirming the good electrochemical reversibility of the materials for Li *** reaction kinetics of Bi_(2)O_(2)CO_(3)@C were further investigated using galvanostatic intermittent titration ***,Bi_2O_(2)-CO_(3)@C exhibited excellent long-term stability,maintaining its high reversible capacity for over 200 cycles at a current density of 0.5 A·g^(-1)in a full cell configuration using Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) as the cathode *** result further underscores its promising potential for lithium-ion *** work may provide inspiration for the design of alloy-type negative electrode materials for high-performance rechargeable batteries.

关键词： Bi_(2)O_(2)CO_(3) Composite materials Anode materials Full batteries

Impact of Multi-Scale Oscillations at High and Low Latitudes on Two Persistent Heavy Rainfall Events in the Middle and Lower Reaches of the Yangtze River

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Journal of Meteorological Research 2016年第5期30卷 662-677页

作者： hui Pinhong FANG juan Key Laboratory of Mesoscale Severe Weather/MOE School of the Atmospheric Sciences Nanjing University Nanjing 210023 Jiangsu Climate Center Jiangsu Provincial Meteorological Bureau Nanjing 210009

To investigate the multi-scale features in two persistent heavy rainfall （PHR） events in the middle and lower reaches of the Yangtze River （MLRYR） in June of 1982 and 1998, this study examines the impact of multi-scale oscillations in the north and south of 30°N on the PHR events by performing sensitivity experiments with the Weather Research and Forecast （WRF） model. It is found that the 60-day low- pass perturbation made a trivial contribution to the MLRYR precipitation during the PHR event in 1982. This PHR event resulted mainly from the combined effects of 30-60-day oscillation at low latitudes and 10-30-day oscillation at both high and low latitudes. The southwesterly anomalies associated with the 30- 60-day anticyclonic anomaly over the northwestern Pacific facilitated moisture transport from the ocean to the MLRYR and enhanced the low-level convergence and ascending motion in the MLRYR. This similarly occurred in the 10-30-day oscillation as well. Moreover, the 10 30-day anomalies at high latitudes played a role in strengthening the large-scale low-level convergence over the MLRYR. The PHR event in 1998 was mainly related to the 60-day oscillation at both high and low latitudes and 30-60-day oscillation at low latitudes. The 60-day low-pass filtered anomalous cyclone at high latitudes in the north of 30°N contributed to the development of low-level convergence and ascending motion in northern MLRYR while the anomalous anticyclone at low latitudes in the south of 30°N not only increased the moisture in the MLRYR but also preconditioned the dynamical factors favorable for PHR over the whole area. The 30-60-day perturbations located north and south of 30°N worked together producing positive moisture anomaly in the MLRYR. In addition, the anomalous circulation in the south of 30°N tended to favor the development of ascending motion and low-level convergence in the MLRYR.

关键词： persistent heavy rainfall (PHR) middle and lower reaches of the Yangtze River (MLRYR) 60-day oscillation 30-60-day oscillation 10-30-day oscillation

A Note on List Edge and List Total Coloring of Planar Graphs without Adjacent Short Cycles

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Acta Mathematica Sinica,English Series 2014年第1期30卷 91-96页

作者： hui juan WANG Jian Liang WU School of Mathematics Shandong University

LetGbe a planar graph with maximum degreeΔ.In this paper,we prove that if any4-cycle is not adjacent to ani-cycle for anyi∈{3,4}in G,then the list edge chromatic numberχl（G）=Δand the list total chromatic number... 详细信息

关键词： List edge coloring list total coloring planar graph cycle

Influence of Cold-Rolling Reduction on Microstructure and Tensile Properties of Nuclear FeCrAl Alloy with Low Cr and Nb Contents

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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2101-2110页

作者： hui Wang Biao guo Xuguang An Yu Zhang Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610213China School of Materials Science and Engineering Xihua UniversityChengdu 610039China Interdisciplinary Materials Research Center Institute for Advanced StudyChengdu UniversityChengdu 610106China

FeCrAl alloy is one of the most promising candidates as an accident-tolerant fuel(ATF)cladding ***,the influence of cold-rolling(CR)reduction on microstructure and tensile properties of the as-annealed FeCrAl alloys,with low Cr and Nb contents,is systematically *** the increase in CR reduction,the grain size of FeCrAl alloy is obviously refined after annealing because the increase in stored deformation energy leads to enhanced ***,the large CR reductions result in a severe mixed-grain microstructure,significantly reducing the uniform deformability of the FeCrAl *** dislocation density of the as-annealed FeCrAl alloy decreases with the increase in CR reduction,except for the excessive CR reduction of 50%.Moreover,the Laves phases are crushed and dissolved during CR and annealing,as well as large amounts of refined Laves phases are found after large CR *** pinning effect of the Laves phases can significantly improve the strength of FeCrAl ***,the strengthening mechanisms of FeCrAl alloy consist of fine-grain strengthening,dislocation strengthening and precipitation ***,the FeCrAl alloy,with a CR reduction of 30%,achieves optimal tensile *** study can provide theoretical guidance for the industrial production of the FeCrAl alloy.

关键词： FeCrAl alloy Cold-rolling reduction Tensile properties Microstructure evolution Strengthening mechanism

High resolution spectroscopy of two young active late type stars within 20 parsecs of the Sun

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Chinese Journal of Astronomy and Astrophysics 2009年第3期9卷 315-322页

作者： hui-juan Wang Jian-Yan Wei National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

We present high-resolution optical echell spectroscopy of HIP 544 and HIP 46843, two nearby solar like stars. The discovery of these young stars at such a close distance to the Sun is really a surprising phenomenon. It will help us to have a better understanding of the structure and evolutionary history of the Milky Way. The radial velocities （RV） of HIP 544 and HIP 46843 are measured to be -6.88±0.13km s^-1 and 8.30±0.16km s^-1, respectively, which are more accurate than before. The equivalent widths （EW） of the Li I 6707.8A absorption line of HIP 544 and HIP 46843 are measured to be 110±5 mA and 195±5 mA respectively. Based on these properties, HIP 544 is estimated to be 100-800Myr old and HIP 46843 30-100Myr old using three relatively creditable methods.

关键词： stars late-type - stars individual (HIP544, HIP46843) - stars activity - techniques radial velocities - techniques spectroscopic