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Seismic modeling by combining the finite-difference scheme with the numerical dispersion suppression neural network

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Petroleum Science 2024年第5期21卷 3157-3165页

作者： hong-Yong yan Key Laboratory of Petroleum Resources Research Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China

Seismic finite-difference(FD) modeling suffers from numerical dispersion including both the temporal and spatial dispersion, which can decrease the accuracy of the numerical modeling. To improve the accuracy and efficiency of the conventional numerical modeling, I develop a new seismic modeling method by combining the FD scheme with the numerical dispersion suppression neural network(NDSNN). This method involves the following steps. First, a training data set composed of a small number of wavefield snapshots is generated. The wavefield snapshots with the low-accuracy wavefield data and the high-accuracy wavefield data are paired, and the low-accuracy wavefield snapshots involve the obvious numerical dispersion including both the temporal and spatial dispersion. Second, the NDSNN is trained until the network converges to simultaneously suppress the temporal and spatial ***, the entire set of low-accuracy wavefield data is computed quickly using FD modeling with the large time step and the coarse grid. Fourth, the NDSNN is applied to the entire set of low-accuracy wavefield data to suppress the numerical dispersion including the temporal and spatial *** modeling examples verify the effectiveness of my proposed method in improving the computational accuracy and efficiency.

关键词： Finite difference Seismic modeling Numerical dispersion suppression Computational accuracy Computational efficiency

Unified gas-kinetic particle method for dilute granular flow and its application in a solid jet

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Acta Mechanica Sinica 2020年第1期36卷 22-34页

作者： Zhao Wang hong yan yangtze River Delta Research Institute of NPU Northwestern Polytechnical UniversityTaicang215400JiangsuChina Shaanxi Key Laboratory of Internal Aerodynamics in Aero-Engine Xi’an710072China

Because of its complexity,the problem of multiscale structure in granular flow has been receiving increasing *** this work,in order to conduct an in-depth exploration of the multiscale structure,a unified gas-kinetic particle(UGKP)method suitable for granular flow is constructed,in which the collision damping term and return-to-isotropy term are added to characterize the collision between *** the above two collision terms,the former characterizes the inelastic collision of particles,while the latter emphasizes the importance of the isotropic distribution of particles,which makes the results more reliable and *** construction of unified gas-kinetic schemes(UGKS)for granular flow has been reported in previous ***,because of the need for discrete velocity space,the calculation size is quite large,making it impossible to use UGKS directly to investigate the multiscale ***,for UGKP,the flux contributed by particle free transport is calculated by free-streaming particles instead of discrete velocity space so that the corresponding calculation is much smaller than *** validity of the method is verified by numerical simulation of the solid jet compared with the particle-in-cell(PIC)*** addition,since the sampled particles are used to obtain the flux contributed by the free transport,UGKP is more efficient than UGKS for solving multiscale problems.

关键词： Granular flow UGKP Multiscale Return-to-isotropy

Density Functional Theory Study of Infrared and Ultraviolet Spectra of Urea L-Malic Acid

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Chinese Journal of Chemical Physics 2008年第6期21卷 535-540页

作者： yan-lan Zhang hong-yan Wang Dong-sheng Jiao Yong-hong Hu Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China College of Sciences Southwest Jiaotong University Chengdu 610031 China College of Life Science and Pharmaceutical Engineering Nanjing University of Technology Nanjing 210009 China

Urea L-malic acid, a new second order nonlinear optical crystal, was studied using density functional theory （DFT）. PBEPBE/6-31＋G（d,p） method, the optimal method for comparing the results from the several DFT methods, was chosen to study the molecular structure. Infrared and ultraviolet-visible spectra were obtained and compared with experiments. The ultraviolet-visible spectrum was also analyzed by the molecular orbital population. The geometries, and the infrared and ultraviolet-visible spectra in water were studied using DFT methods in combination with the polarized continuum model to predict the perturbations by the solvent effect.

关键词： Urea L-malic acid Density functional theory Molecular structure Infrared spectrum Ultraviolet-visible spectrum

热塑性纤维素与PVA混溶性的分子动力学模拟

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原子与分子物理学报 2025年第3期42卷 149-158页

作者：冯彦洪陈帅杰孙航华南理工大学机械与汽车工程学院聚合物新型成型装备国家工程研究中心聚合物成型加工工程教育部重点实验室广东省高分子先进制造技术及装备重点实验室广州510000

首次提出了将氧化还原改性纤维素(Oxidation-reduction modified cellulose,ORC)与聚乙烯醇(Poly(vinyl alcohol),PVA)共混进行制备复合材料,并采用分子动力学模拟研究了ORC与PVA的混溶性.对分子链间相互作用能和氢键数量分析发现,随着... 详细信息

首次提出了将氧化还原改性纤维素(Oxidation-reduction modified cellulose,ORC)与聚乙烯醇(Poly(vinyl alcohol),PVA)共混进行制备复合材料,并采用分子动力学模拟研究了ORC与PVA的混溶性.对分子链间相互作用能和氢键数量分析发现,随着改性程度增加,ORC与PVA会产生更强烈的相互作用,这促进了组分间的混溶.当ORC的改性程度达到40%后,ORC与PVA的溶解度参数差值为2.02(J/cm^(3))^(1/2),达到混溶条件.根据Flory-Huggins理论确定了醇解度为88%和99%的PVA与ORC的混溶性,结果表明PVA(88%)与ORC的混溶性更好.对共混体系中形成氢键原子的径向分布函数分析发现,醋酸乙烯酯重复单元上的羰基更倾向与ORC形成分子链间氢键,而乙烯醇重复单元上的羟基更倾向形成分子链内氢键,这促使PVA(88%)/ORC共混体系中形成更多的分子链间氢键,从而混溶性更好.研究结果可为ORC/PVA复合材料的制备提供理论指导.

关键词：混溶性氧化还原改性纤维素分子动力学聚乙烯醇

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Impact of community public health care on treatment effect,health cognition,and self-management in patients with type 2 diabetes

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World Journal of Clinical Cases 2025年第5期13卷 22-29页

作者： hong Shi Chun Liu hong-yan Luo Department of Infrastructure Operation West China Hospital of Sichuan UniversityChengdu 610041Sichuan ProvinceChina Department of Public Health Minzu Street Community Health Service CenterWuhan 430000Hubei ProvinceChina Caotang Community Health Service Center Chengdu 610031Sichuan ProvinceChina

BACKGROUND At present,China has become the country with the largest number of individuals with diabetes mellitus(DM)in the world,with a total of approximately 140 million patients,the majority of whom have type 2 DM(T2DM).Based on conven-tional nursing methods,community home care has important clinical significance in controlling blood sugar and disease *** To explore the impact of community public health nursing on treatment effect,health cognition,and self-management in patients with *** One hundred patients with T2DM were selected as the research *** patients were divided into either a conventional nursing group or community nursing(CN)group using the random number table *** conventional nursing group(50 cases)received routine care,while the CN group(50 cases)received community public health care in addition to routine care as that for the conventional nursing *** rate of excellent and good blood glucose control,fasting blood glucose before and after care,2-h postprandial blood glucose,health cognition,and self-management ability,and patient satisfaction were compared between the two *** The CN group had a higher rate of excellent blood sugar control than the conventional nursing group(88%vs 70%,P0.05).After nursing,fasting blood glucose and 2-h postprandial blood glucose were reduced to varying degrees in both groups,and both blood glucose levels in the CN group were lower than those of the conventional nursing group(P<0.05).Compared with the scores before care,the cognitive level score for diabetes and self-management ability score improved after care in both *** cognitive level and self-management ability of patients in the CN group were higher than those of the conventional nursing group(P<0.05).The overall satisfaction of the CN group was better than

关键词： Community public health care Type 2 diabetes Blood sugar control Self-management ability Cognition level

Recent advances in radical-mediated fluorination through C-H and C-C bond cleavage

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Science China Chemistry 2017年第2期60卷 214-222页

作者： hong yan Chen Zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China

The C-H and C-C bonds are abundant in organic compounds,yet generally inert in chemical ***,direct functionalization of inert chemical bonds remains *** fluorine-containing compounds are of special interest for their uses in medicinal *** fluorination of C-H and C-C bonds undoubtedly represents one of the most ideal and attractive approaches to incorporate fluorine atom into complex ***,we summarize the recent advances in radical-mediated C-H and C-C bond *** types of transformations are discussed:(1)direct C-H abstraction/fluorination of alkanes;(2)decarboxylative fluorination of alkyl carboxylic acids;(3)ring-opening fluorination.

关键词： fluorination C-H functionalization decarboxylation ring-opening radical

THE DATA ENVELOPMENT ANALYSIS MODEL WITH INTERSECTION FORM PRODUCTION POSSIBILITY SET

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Journal of Systems Science & Complexity 2010年第6期23卷 1086-1101页

作者： Quanling WEI hong yan Institute of Operations Research and Mathematical Economics Renmin University of China Beijing 100872 China. Department of Logistics The Hongkong Polytechnic University Hongkong China.

The data envelopment analysis （DEA） model is used to evaluate the relative economic efficiency of a given set of decision making units （DMUs）. In this paper, the DEA production possibility set is transferred from the conventional sum form into the intersection form which is represented by a linear inequality system. Although it is time consuming to obtain the intersection form of the production possibility set, it suggests a new angle to investigate the properties of DMUs and to extend the DEA research further beyond the efficiency measurement. Following the intersection form, the analytical formula of the efficiency indicator and projection is given. Various aspects of technical efficiency, returns to scale and evidence of congestion of the DMUs are studied. The relationship between the weak DEA efficiency and the weak Pareto solution is discussed. Finally, a procedure for DMU grouping is proposed to help the decision makers for better resource reallocation and strategy adjustment.

关键词： Data envelopment analysis intersection form production possibility set.

A Central Limit Theorem for Branching Brownian Motion with Random Immigration

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Acta Mathematica Sinica,English Series 2014年第1期30卷 69-78页

作者： hong yan SUN School of Mathematical Sciences Beijing Normal University

We establish a central limit theorem for a branching Brownian motion with random immigration under the annealed law,where the immigration is determined by another branching Brownian *** limit is a Gaussian random measure and the normalization is t3/4for d=3 and t1/2for d≥4,where in the critical dimension d=4 both the immigration and the branching Brownian motion itself make contributions to the covariance of the limit.

关键词： Branching Brownian motion random immigration central limit theorem occupation time

Microstructure and properties of mullite-based porous ceramics produced from coal fly ash with added Al_2O_3

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International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 309-315页

作者： Jian-bin Zhu hong yan Department of Materials Processing Engineering School of Mechanical Electrical EngineeringNanchang University School of Mechanical Electrical Engineering Nanchang Institute of Technology

Using coal fly ash slurry samples supplemented with different amounts of Al2O3, we fabricated mullite-based porous ceramics via a dipping-polymer-replica approach, which is a popular method suitable for industrial application. The microstructure, phase composition, and compressive strength of the sintered samples were investigated. Mullite was identified in all of the prepared materials by X-ray diffraction analysis. The microstructure and compressive strength were strongly influenced by the content of Al2O3. As the Al/Si mole ratio in the starting materials was increased from 0.84 to 2.40, the amount of amorphous phases in the sintered microstructure decreased and the compressive strength of the sintered samples increased. A further increase in the Al2O3content resulted in a decrease in the compressive strength of the sintered samples. The mullite-based porous ceramic with an Al/Si molar ratio of 2.40 exhibited the highest compressive strength and the greatest shrinkage among the investigated samples prepared using coal fly ash as the main starting material. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

关键词： Aluminum Amorphous materials Ceramic materials Coal Coal ash Fly ash Microstructure Mullite Porous materials Silicate minerals Sintering Strength of materials X ray diffraction analysis