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An adaptive finite-difference method for seismic traveltime modeling based on 3D eikonal equation

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Petroleum Science 2024年第1期21卷 195-205页

作者： Bao-Ping Qiao qing-qing Li Wei-Guang He Dan Zhao Qu-bo Wu CNNC Beijing Research Institute of Uranium Geology Beijing 100029China National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShangdongChina SINOPEC Geophysical Research Institute Nanjing211103JiangsuChina

3D eikonal equation is a partial differential equation for the calculation of first-arrival traveltimes and has been widely applied in many scopes such as ray tracing,source localization,reflection migration,seismic monitoring and tomographic *** recent years,many advanced methods have been developed to solve the 3D eikonal equation in heterogeneous ***,there are still challenges for the stable and accurate calculation of first-arrival traveltimes in 3D strongly inhomogeneous *** this paper,we propose an adaptive finite-difference(AFD)method to numerically solve the 3D eikonal *** novel method makes full use of the advantages of different local operators characterizing different seismic wave types to calculate factors and traveltimes,and then the most accurate factor and traveltime are adaptively selected for the convergent updating based on the Fermat *** with global fast sweeping describing seismic waves propagating along eight directions in 3D media,our novel method can achieve the robust calculation of first-arrival traveltimes with high precision at grid points either near source point or far away from source point even in a velocity model with large and sharp *** numerical examples show the good performance of the AFD method,which will be beneficial to many scientific applications.

关键词： 3D eikonal equation Accurate traveltimes Global fast sweeping 3D inhomogeneous media Adaptive finite-difference method

A Time-dependent Interaction Problem Between an Electromagnetic Field and an Elastic body

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Acta Mathematicae Applicatae Sinica 2020年第1期36卷 95-118页

作者： Chang-kun WEI Jia-qing YANG bo ZHANG Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Mathematics and Statistics Xi’an Jiaotong UniversityXi’an 710049China

This paper considers the scattering of a time-dependent electromagnetic plane wave by a bounded elastic *** appropriate decomposition of the coupling interface conditions is proposed according to the Voigt’s model between the electromagnetic and elastic *** original unbounded scattering problem is equivalently reduced into an initial-boundary value problem in a bounded domain by introducing an exact transparent boundary condition(TBC)on a sufficiently large *** use of the Lax-Milgram lemma,the abstract inversion theorem of Laplace transform and the energy method,we verify the well-posedness and stability for the reduced ***,a priori estimates are established for the electromagnetic field and elastic displacement by taking special test functions directly in the time domain variational formulation.

关键词： electromagnetic elastic Laplace transform Lax-Milgram lemma energy method well-posedness

Influence of Torsion Deformation on Textures of Cold Drawing Pearlitic Steel Wires

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 707-714页

作者： Ning Guo bo Song Bing-Shu Wang qing Liu Faculty of Materials and Energy Southwest University Department of Materials Science and Engineering Chongqing University Department of Materials Science and Engineering Fuzhou University

The influence of torsion deformation on textures of cold drawing pearlific steel wires was investigated by twisting the wires to different number of revolutions. Macro-texture （over the entire wire cross section） associated with torsion deformation was investigated by X-ray diffraction, while micro-texture （near the wire surface） was characterized by EBSD. The results show that the （110） macro-texture increases at the beginning of torsion and then decreases with increasing of torsion strain, while the （110） micro-texture decreases linearly with increasing of torsion strain. The relationships between the （110） fiber texture and the microhardness of the wires are also discussed.

关键词： Pearlite Cold drawing Torsion Texture

CONVERGENCE ANALYSIS OF PARAREAL ALGORITHM BASED ON MILSTEIN SCHEME FOR STOCHASTIC DIFFERENTIAL EQUATIONS

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Journal of Computational Mathematics 2020年第3期38卷 487-501页

作者： Liying Zhang Jing Wang weien Zhou Landong Liu Li Zhang School of Mathematical Science China University of Mining and TechnologyBeijing 100083China National Innovation Institute of Defense Technology Chinese Academy of Military ScienceBeijing 100101China Department of Foundation Courses Beijing Union UniversityBeijing 100101China

In this paper,we propose a parareal algorithm for stochastic differential equations(SDEs),which proceeds as a two-level temporal parallelizable integrator with the Milstein scheme as the coarse propagator and the exact solution as the fine *** convergence order of the proposed algorithm is analyzed under some regular ***,numerical experiments are dedicated to illustrate the convergence and the convergence order with respect to the iteration number k,which show the efficiency of the proposed method.

关键词： Stochastic differential equations Parareal algorithm Convergence Stochastic Taylor expansion Milstein scheme

Thermo-Hydraulic Characteristics of Non-Isothermal Batch Transportation Pipeline System with Different Inlet Oil Temperature

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Journal of Thermal Science 2023年第3期32卷 965-981页

作者： CHEN Zhimin YUAN qing JIANG Weixin LI Zongze YU bo School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an 710049China Faculty of Environment and Life Beijing University of TechnologyBeijing 100124China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

The batch transportation process of several kinds of crude oil is accomplished by an entire coupled pipeline system,which exhibits complex thermo-hydraulic *** on the coupled characteristics among soil,pipelines and devices(including pumps,heating furnaces and valves),a coupled simulation model of batch transportation for the crude oil pipeline system is established,and a novel coupled simulation algorithm is *** simulation results are in good agreement with the field data of an actual crude oil pipeline *** addition,based on the numerical simulation,thermo-hydraulic characteristics of pipeline system are investigated,and some new thermo-hydraulic characteristics are *** the batch transportation process with constant flowrate,the change trends of temperature at the outlet of each pipeline segment are hysteretic and the change ranges of temperature become small along *** the adjustment of devices influences thermohydraulic characteristics to some *** the batch transportation process with variable flowrate,the complex thermo-hydraulic characteristics are exhibited,which are induced by the comprehensive influence of the changes of oil type,flowrate and absorbed/released *** with the transportation process with constant flowrate,the high-viscosity oil exhibits similar minimum temperature and lower maximum pressure in the transportation process with variable flowrate,which means that the higher transportation safety of pipeline system is *** study can provide a scientific reference for making the safer batch transportation scheme of crude oil pipeline system.

关键词： crude oil pipeline system batch transportation coupled simulation variable flowrate thermo-hydraulic characteristics

Risk factors for Clostridioides difficile infection in children and adolescents with inflammatory bowel disease: a systematic review and meta-analysis

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World Journal of Pediatrics 2022年第1期18卷 27-36页

作者： Sheng-bo Fang Yan-qing Song Chun-Yan Zhang Li-bo Wang Department of Pharmacy First Hospital of Jilin UniversityChangchunChina Department of Pediatric Gastroenterology Unit First Hospital of Jilin University71 Xinmin StreetChangchun130021China

Background Risk factors and consequences associated with Clostridioides difficile infection(CDI)in children and adolescents with inflammatory bowel disease(IBD)are still *** conduct a systematic review and meta-analysis to assess risk factors and outcomes associated with CDI in children and adolescents with *** PubMed,EMBASE and Cochrane Library databases were searched from inception to 24th February,*** investigating risk factors,bowel surgery rate in pediatric IBD patients with and without CDI were ***-effects model was used for calculating summary ***–Ottawa scale(NOS)was used for quality *** Fourteen studies,comprising 17,114 patients,were *** was a significant association between 5-aminosalicylic acid(5-ASA)use and CDI[odds ratio(OR)=1.95,95%confidence interval(CI)1.26–3.03],with minimal heterogeneity(I^(2)=0.00%).Increased risk of active disease(OR=4.66,95%CI 2.16–10.07)were associated with CDI in those studies performed in high quality score(NOS>6)and significantly higher CDI rates in studies conducted outside USA(OR=2.94,95%CI 1.57–5.58).The bowel surgery rate in IBD with CDI was 3.8–57.1%,compared to that in IBD without CDI(0–21.3%).All studies were of moderate to high *** 5-ASA use and active disease might be risk factors associated with CDI in children and adolescents with *** surgery rates associated with CDI in IBD patients varied ***-scale clinical studies on CDI in children and adolescents with IBD are still needed to verify risk factors and outcomes.

关键词： Adolescent Children Clostridioides difficile infection Inflammatory bowel disease

Regioregular Asymmetric Diketopyrrolopyrrole Copolymers with Good Molecular Ordered Assembly Ability for High-performance Polymer Transistors

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Chinese Journal of Polymer Science 2023年第8期41卷 1215-1222,I0006页

作者： qing-qing Liu Jia-Xin Yang Man Zhao Can Gao bo Guan Huan-Li Dong Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

Introduction of asymmetric units into conjugated polymers is an important strategy to regulate the photophysical and electronic properties of polymers,as asymmetric units can not only regulate solubility and energy levels,but also molecular stacking and orientation,thus giving much higher optoelectronic ***,very few studies have been reported in this *** semiconducting properties of conjugated polymers could be regulated through regioregularity ***,we took the asymmetric thiophene/pyridine side group DPP as core and developed the regioregular monomer T-Py-DPP through three steps:alkyl chain introduction,tin monomer coupling and NBS double *** T-Py-DPP monomer was polymerized into reg-PPy TDPP-2FBT with a head-to-head *** regioregularity of T-Py-DPP unit endowed reg-PPy TDPP-2FBT with backbone planarity,self-assembly orientation,network-like morphology and high crystallinity in films,thus the superior bipolar transport *** highest hole and electron mobilities of reg-PPy TDPP-2FBT were 0.93 and 0.57 cm^(2)·V^(-1)·s^(-1),respectively,with 40%improvement relative to the regiorandom polymer.

关键词： Asymmetric copolymers Regioregularity Good orientation Organic field-effect transistor Enhanced performance

Near-infrared organic photosensitizers with aggregation-induced emission and switchable fluorescence for fungal infection therapy

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Science China Chemistry 2025年

作者： Xinzhe Yang Zixuan Huang Keke Ding Huili Yang Lirong Wang qing Xia Rong Hu Guang Shi Bingjia Xu Anjun Qin School of Chemistry South China Normal University State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates Center for Aggregation-Induced Emission AIE Institute South China University of Technology Department of Urology The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College) School of Chemistry and Chemical Engineering University of South China

The development of near-infrared (NIR) photosensitizers with aggregation-induced emission (AIE) properties,switchable luminescence colors,and satisfactory photodynamic therapy (PDT) effects on the treatment of fungal infection is of great importance but very ***,two ionic organic luminogens are constructed by employing diphenylamine,diphenylacrylonitrile/1,2-diphenylethene,and methylated quinoline cation as building *** is found that the resulting compounds TCQF and TQF show apparent AIE properties and produce intense fluorescence with high photoluminescence quantum yields of up to 31.2%in the solid *** the meantime,their emission colors can be switched between red and NIR and in the NIR region by mechanical force and solvent vapor,respectively,thereby enabling remarkable and reversible mechanochromism with emission variations of up to 104 *** excitingly,TCQF and TQF can efficiently generate ROS under the illumination of white light and show excellent antimicrobial activities and satisfactory PDT *** by the unique anti-fungus properties,TCQF is employed as a biocompatible NIR photosensitizer for treating wound infection with ***,and apparent PDT effects are *** work provides a new direction for the development of multifunctional NIR materials with AIE properties.

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Regulation of substrate surface topography on differentiation of mesenchymal stem cells

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Acta Mechanica Sinica 2020年第5期36卷 1158-1169,I0004页

作者： bo Huo Yang Zhao Xue Bai qing Sun Fei Jiao Biomechanics Lab Department of MechanicsSchool of Aerospace EngineeringBeijing Institute of TechnologyBeijing 100081China

Mesenchymal stem pells(MSCs)have been extensively used in the field of tissue engineering and regenerative *** effect of surface properties on the differentiation of MSCs is a very important issue for the design and fabrication of scaffolds or *** review is mainly focused on the morphological or topographic characteristics of cell adhesion substrate,*** area and shape for individual cell,cell density and cell-cell contact for multiple cells,substrate roughnessridge width,micropillar height,nanoparticle diameter and aspect ratio of *** results from different studies were quantitativcly analyzed using comparable or unified parameters and definitions under the specific experimental conditions such as cell source,culture time,induction medium,matrix material and differentiation *** interesting phenomena and properties were discovered by this integrated and systematic analysis,which might give insights into the regulatory mechanism of surface morphology or topography on MSCs differentiation.

关键词： Mesenchymal stem cell Adhesion morphology Surface topography Differentiation Biomaterial