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A meshless algorithm with the improved moving least square approximation for nonlinear improved Boussinesq equation

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Chinese Physics B 2021年第1期30卷 126-133页

作者： Yu Tan xiao-lin li School of Mathematical Sciences Chongqing Normal UniversityChongqing 400047China

An improved moving least square meshless method is developed for the numerical solution of the nonlinear improved Boussinesq equation. After the approximation of temporal derivatives, nonlinear systems of discrete algebraic equations are established and are solved by an iterative algorithm. Convergence of the iterative algorithm is discussed. Shifted and scaled basis functions are incorporated into the method to guarantee convergence and stability of numerical results. Numerical examples are presented to demonstrate the high convergence rate and high computational accuracy of the method.

关键词： meshless improved moving least square approximation nonlinear improved Boussinesq equation convergence and stability

You Are How You Behave-Spatiotemporal Representation Learning for College Student Academic Achievement

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Journal of Computer Science & Technology 2020年第2期35卷 353-367页

作者： xiao-lin li li Ma Xiang-Dong He Hui Xiong School of Business Nanjing UniversityNanjing 210093China Information Technology Services Center Nanjing UniversityNanjing 210093China School of Business Rutgers UniversityNewarkNJ 07102U.S.A.

Scholarships are a reflection of academic achievement for college *** traditional scholarship assignment is strictly based on final grades and cannot recognize students whose performance trend improves or declines during the *** paper develops the Trajectory Mining on Clustering for Scholarship Assignment and Academic Warning(TMS)approach to identify the factors that affect the academic achievement of college students and to provide decision support to help low-performing students attain better ***,we first conduct feature engineering to generate a set of features to characterize the lifestyles patterns,learning patterns,and Internet usage patterns of *** then apply the objective and subjective combined weighted k-means(Wosk-means)algorithm to perform clustering analysis to identify the characteristics of different student *** the difficulty in obtaining the real global positioning system(GPS)records of students,we apply manually generated spatiotemporal trajectories data to quantify the direction of trajectory deviation with the assistance of the PrefixSpan algorithm to identify low-performing *** experimental results show that the silhouette coefficient and Calinski-Harabasz index of the Wosk-means algorithm are both approximately 1.5 times to that of the best baseline algorithm,and the sum of the squared error of the Wosk-means algorithm is only the half of the best baseline algorithm.

关键词： academic achievement spatiotemporal trajectory feature engineering student segmentation

Influence of cooling rate on phase transformation and precipitation behavior of Ti-bearing steel in continuous cooling process

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Journal of Iron and Steel Research International 2022年第1期29卷 165-174页

作者： xiao-lin li Chi Jin Hao-zhe li xiao-xiao Hao Yi He Xiang-tao Deng Zhao-dong Wang State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072ShaanxiChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

The influence of cooling rate on microstructural evolution and precipitation behavior in Ti,Ti–Nb and Ti-Mo low-carbon steels during the continuous cooling process was studied by dilatometer method,optical microscopy,and transmission electron *** results indicated that austenite transformation temperature decreased with the increasing cooling rate in three *** addition of Nb and Mo promoted bainite and martensite transformation and improved the hardenability of *** addition,precipitates formed in deformed austenite and ferrite can be observed *** in the austenite non-recrystallization zone can introduce a large number of deformation bands,and then,the precipitates preferentially nucleated in these deformation *** the following process,randomly distributed precipitates and interphase precipitates will be formed in *** precipitates formed in deformed austenite obey Kurdjumov-Sachs orientation relationship with the matrix,while the precipitates formed in ferrite obey Baker-Nutting orientation relationship with the *** addition of Nb and Mo in Ti-bearing steels decreased the precipitates size and increased the number density of precipitates and then improved the precipitation *** the effect of Mo addition is more obvious than that of Nb addition.

关键词： Ti-microalloyed steel Continuous cooling transformation Precipitation behavior Precipitate-free zone Orientation relationship

Influence of plasma peening on oxidation of H13 hot work steel in water vapor

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 305-309页

作者： MIN Yong-an XU xiao WU xiao-chun li lin XU Luo-ping School of Materials Science and Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai University Shanghai 200072 China School of Materials Science and Engineering Shanghai University Shanghai 200072 China

The surface oxidation films on H13 steel samples, obtained by different oxidation processes were observed by optical microscope. It is shown that the oxidation speed of H13 steel is increased remarkably due to the surface modification of plasma peening. Further researches were made by XRD, SEM and EDS. The activation of H13 surface caused by plasma peening and the subsequent higher oxygen diffusion rate into the steel seem to be the main reasons of higher oxidation speed. The nitride layer, generally formed on the steel surface under plasma nitriding process, can be substituted by oxide in subsequent oxidation process, which can reduce the risk of heat cracking in some hot work applications. Therefore, the plasma nitriding plus oxidation process is a proper choice for some hot work dies, which demands high hardness to avoid indentation as well as high toughness to avoid cracks.

关键词： oxidation hot work tool steel plasma nitriding surface treatment

Nonuniform Approach to Terminal Velocity for Single Mode Rayleigh-Taylor Instability

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Acta Mathematicae Applicatae Sinica 2002年第1期18卷 1-8页

作者： James Glimm xiao-lin li An-Der lin Department of Applied Mathematics and Statistics University at Stony BrookStony BrookNY 11794-3600USA Center for Data Intensive Computing Brookhaven National LaboratoryUpton NY 11973USADepartment of Applied Mathematics and StatisticsUniversity at Stony BrookStony BrookNY 11794-3600USADepartment of Applied Mathematics and StatisticsUniversity at Stony BrookStony BrookNY 11794-3600USA

The temporal development of a single mode Rayleigh-Taylor instability consists of three stages: the linear, free fall and terminal velocity regimes. The purpose of this paper is to report on new phenomena observed in the approach to terminal velocity. Our numerical study shows an unexpected nonuniform approach to terminal velocity. The nonuniformity applies especially to the spikes, which are fingers of heavy fluid falling into the light fluid, but it also applies to the rising bubbles of light fluid. For spikes especially, our results call into question the meaningfulness of a terminal velocity for moderate values of the Atwood number A. After a short time period of pseudo-terminal plateau, the spike velocity increases to a significantly higher maximum, followed by a decrease. This phenomena appears to be due to a slow evolution in the shape of the spike and bubble. We find a relation between the spike (bubble) acceleration and the tip curvature. In correlation with an increase in the spike velocity, the main body of the spike becomes narrower and the tip curvature increases. Our numerical results are by the Front Tracking method. The very late time simulations considered here required stabilization by a small value for the viscosity, so that the compressible Navier-Stokes equations govern the dynamics.

关键词： Rayleigh-Taylor instability terminal velocity

Manipulating transition of a two-component Bose–Einstein condensate with a weak δ-shaped laser

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Chinese Physics B 2019年第10期28卷 263-268页

作者： Bo li xiao-Jun Jiang xiao-lin li Wen-Hua Hai Yu-Zhu Wang Key Laboratory for Quantum Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Department of Physics and Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education Hunan Normal UniversityChangsha 410081China

We theoretically study the transition dynamics of a two-component Bose-Einstein condensate driven by a train of weak δ-shaped laser pulses. We find that the atomic system can experience peculiar resonant transition even under weak optical excitations and derive the resonance condition by the perturbation method. Employing this mechanism, we propose a scheme to obtain an atomic ensemble with desired odd/even atom number and also a scheme to prepare a nonclassical state of the many-body system with fixed atom number.

关键词： two-component Bose-Einstein condensate quantum kicked top model nonclassical state

Ni-Catalyzed Enantioselective Difunctionalization of Alkynes to Azepine Derivatives Bearing a Quaternary Center and an Unprotected Imine

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Chinese Journal of Chemistry 2024年第8期42卷 873-878页

作者： Jian Long Zhiwu Lu xiao-lin li Peng Xue Wen-Bo liu Engineering Research Center of Organosilicon Compounds&Materials(Ministry of Education)and College of Chemistry and Molecular Sciences Wuhan UniversityWuhanHubei430072 China

Comprehensive Summary,The azepine ring is a prominent structural scaffold in biologically significant molecules. In this study, we present a Ni(II)-catalyzed asymmetric difunctionalization of alkynes, involving intermolecular regioselective arylation and intramolecular nitrile addition, enabling the synthesis of enantioenriched azepine derivatives. This reaction simultaneously installs an all-carbon quaternary stereocenter and introduces an unprotected imine functionality, showing great promise for subsequent transformations. The reaction exhibits good tolerance toward various functional groups, resulting in high yields and enantioselectivities. The synthetic utility of this methodology is further demonstrated through gram-scale synthesis and product derivatization. This research offers an efficient approach to the synthesis of seven-membered nitrogen heterocycles.

关键词： Nickel Asymmetric catalysis N-Heterocycles Alkyne functionalization Quaternary centers

Gastric cancer cell lines induced by trichostatin A

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World Journal of Gastroenterology 2008年第30期14卷 4810-4815页

作者： xiao-Ming Zou Yun-Long li Hao Wang Wu Cui xiao-lin li Song-Bin Fu Hong-Chi Jiang Department of General Surgery the Second Clinical College Harbin Medical University Harbin 150086 Heilongjiang Province China Laboratory of Medical Genetics Harbin Medical University Harbin 150081 Heilongjiang Province China Department of General Surgery the First Clinical College Harbin Medical University Harbin 150081 Heilongjiang Province China

AIM： To explore the effect of trichostatin A （TSA） on apoptosis and acetylated histone H3 levels in gastric cancer cell lines BGC-823 and SGC-7901. METHODS： The effect of TSA on growth inhibition and apoptosis was examined by MTT, fluorescence microscopy and PI single-labeled flow cytometry. The acetylated histone H3 level was detected by Western blot. RESULTS： TSA induced apoptosis in gastric cancer cell lines BGC-823 and SGC-7901 was in a dose and time-dependent manner. Apoptotic cells varied significantly between TSA treated groups （37.5 ng/mL 72 h for BGC-823 cell line and 75 ng/mL 72 h for SGC-7901 cell line） and control group （0.85 ± 0.14 vs 1.14 ± 0.07, P = 0.02; 0.94 ± 0.07 vs 1.15 ± 0.06, P = 0.02）. Morphologic changes of apoptosis, including nuclear chromatin condensation and fluorescence strength, were observed under fluorescence microscopy. TSA treatment in BGC-823 and SGC-7901 cell lines obviously induced cell apoptosis, which was demonstrated by the increased percentage of sub-G1 phase cells, the reduction of Gl-phase cells and the increase of apoptosis rates in flow cytometric analysis. The result of Western blot showed that the expression of acetylated histone H3 increased in BGC-823 and SGC-7901 TSA treatment groups as compared with the control ***： TSA can induce cell apoptosis in BGC-823 and SGC-7901 cell lines. The expression of acetylated histone H3 might be correlated with apoptosis.

关键词： BGC-823 SGC-7901 Trichostatin A Apoptosis Acetylated histone H3 Gastric cancer

Investigation on hydrogen absorption/desorption properties of as-cast La(1-x)Mg_xNi4.25Al0.75(x=0.0, 0.1, 0.2, 0.3) alloys for tritium storage

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Nuclear Science and Techniques 2016年第2期27卷 26-34页

作者： li-Jun Lu Hong-Hui Cheng Xing-Bo Han Guan-Hong Lei Wei liu xiao-lin li Shanghai Institute of Applied Physics Chinese Academy of Sciences Jiading Campus Shanghai 201800 China College of Mechanical Engineering Yangzhou UniversityYangzhou 225127 China University of Chinese Academy of Sciences Beijing 100049China

La_((1-x))Mg_xNi_(4.25)Al_(0.75)(x = 0.0, 0.1, 0.2, 0.3)alloys for tritium storage were prepared by a method of electromagnetic induction melting. The crystal structure and hydrogen storage performance of the as-cast alloys were investigated. The results showed that a single phase of La Ni_4Al was in the alloys with x = 0.0 and 0.1 and that LaNi_4Al and second phase of(La,Mg)Ni)_3 and AlNi_3 were in the alloys with x = 0.2 and 0.3. On the other hand, the plateau pressures of P–C isotherms of the alloys were increased with the rise of the x value from 0.2 to 0.3 and the hydrogen storage capacity was obviously degraded simultaneously. It was found that the alloy had faster absorption kinetics as the proportion of Mg increased from 0.1 to 0.3.

关键词：储氢合金铸态合金吸放氢性能 La 氚吸收动力学感应熔炼制备方法