检索结果-南通市图书馆

Energy Stable Nodal DG Methods for Maxwell’s Equations of Mixed-Order Form in Nonlinear Optical Media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第1期6卷 30-63页

作者： Maohui Lyu Vrushali A.Bokil yingda cheng Fengyan Li State Key Laboratory of Scientific and Engineering Computing(LSEC) Academy of Mathematics and System SciencesChinese Academy of SciencesBeijing100190China Department of Mathematics College of ScienceOregon State UniversityCorvallisOR97331USA Department of Mathematics Michigan State UniversityEast LansingMI48824USA Department of Computational Mathematics Science and EngineeringMichigan State UniversityEast LansingMI48824USA Department of Mathematical Sciences Rensselaer Polytechnic InstituteTroyNY12180USA

In this work,we develop energy stable numerical methods to simulate electromagnetic waves propagating in optical media where the media responses include the linear Lorentz dispersion,the instantaneous nonlinear cubic Kerr response,and the nonlinear delayed Raman molecular vibrational *** the first-order PDE-ODE governing equations considered previously in Bokil et al.(J Comput Phys 350:420–452,2017)and Lyu et al.(J Sci Comput 89:1–42,2021),a model of mixed-order form is adopted here that consists of the first-order PDE part for Maxwell’s equations coupled with the second-order ODE part(i.e.,the auxiliary differential equations)modeling the linear and nonlinear dispersion in the *** main contribution is a new numerical strategy to treat the Kerr and Raman nonlinearities to achieve provable energy stability property within a second-order temporal discretization.A nodal discontinuous Galerkin(DG)method is further applied in space for efficiently handling nonlinear terms at the algebraic level,while preserving the energy stability and achieving high-order *** with d_(E)as the number of the components of the electric field,only a d_(E)×d_(E)nonlinear algebraic system needs to be solved at each interpolation node,and more importantly,all these small nonlinear systems are completely decoupled over one time step,rendering very high parallel *** evaluate the proposed schemes by comparing them with the methods in Bokil et al.(2017)and Lyu et al.(2021)(implemented in nodal form)regarding the accuracy,computational efficiency,and energy stability,by a parallel scalability study,and also through the simulations of the soliton-like wave propagation in one dimension,as well as the spatial-soliton propagation and two-beam interactions modeled by the two-dimensional transverse electric(TE)mode of the equations.

关键词： Maxwell’s equations Kerr and Raman Discontinuous Galerkin method Energy stability

An Adaptive Multiresolution Ultra-weak Discontinuous Galerkin Method for Nonlinear Schrödinger Equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2022年第1期4卷 60-83页

作者： Zhanjing Tao Juntao Huang Yuan Liu Wei Guo yingda cheng School of Mathematics Jilin UniversityJilin 130012China Department of Mathematics Michigan State UniversityEast LansingMI 48824USA Department of Mathematics Statistics and PhysicsWichita State UniversityWichitaKS 67260USA Department of Mathematics and Statistics Texas Tech UniversityLubbockTX 70409USA Department of Mathematics Department of Computational MathematicsScience and EngineeringMichigan State UniversityEast LansingMI 48824USA

This paper develops a high-order adaptive scheme for solving nonlinear Schrödinger *** solutions to such equations often exhibit solitary wave and local structures,which make adaptivity essential in improving the simulation *** scheme uses the ultra-weak discontinuous Galerkin(DG)formulation and belongs to the framework of adaptive multiresolution *** numerical experiments are presented to demon-strate the excellent capability of capturing the soliton waves and the blow-up phenomenon.

关键词： Multiresolution Sparse grid Ultra-weak discontinuous Galerkin method Schrödinger equation Adaptivity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于时空关系的高速公路交通流量预测

工程科学学报 2024年第9期46卷 1623-1629页

作者：田俊山曾俊铖丁峰徐劲江龑周成李英达王歆远福建省高速公路科技创新研究院有限公司福州350000 龙岩东环高速公路有限责任公司福州364000 福建省高速公路集团有限公司福州管理分公司福州350001 北京百度网讯科技有限公司北京100085 北京理工大学北京100081

高速公路交通流量预测对于交通拥堵预警、分流诱导和智慧高速公路建设具有重要意义.交通流具有复杂的时空依赖性,各个交通节点之间的空间关系随时间动态变化,时空关系的融合也缺乏高效的手段,因此对交通流量进行准确的预测具有挑战性.对... 详细信息

高速公路交通流量预测对于交通拥堵预警、分流诱导和智慧高速公路建设具有重要意义.交通流具有复杂的时空依赖性,各个交通节点之间的空间关系随时间动态变化,时空关系的融合也缺乏高效的手段,因此对交通流量进行准确的预测具有挑战性.对此,提出一种基于动态图卷积网络与时空特征提取模块的高速公路交通流量预测方法.首先,通过动态图调节模块,提取交通流量序列的空间关系,根据提取到的空间特征,计算不同路网节点的道路相似性,并调整交通路网图结构;其次,通过时空特征提取模块,利用更新后的空间结构,结合时序处理方法,对交通流量数据的时空依赖关系进行建模.为检验模型效果,在美国加州高速公路性能测量系统(Performance measurement system,PeMS)所制作的数据集PeMS03、PeMS04、PeMS08和福州京台线高速公路数据集中进行实验对比,平均绝对误差分别为15.6、19.7、16.8和5.21,结果表明,本文提出的方法在高速公路交通流量预测中具有较好的表现.

关键词：交通工程交通流预测时空预测图神经网络图卷积高速路网交通流

在线全文

学校读者我要写书评

暂无评论

治疗带状疱疹药物的临床应用

天津药学 1997年第1期9卷 25-26页

作者：张澄义程英达天津医科大学总医院天津300052

本文对治疗带状疱疹的药物，从有效性、安全性方面进行了选择和介绍。便于临床合理用药，提高疗效。

关键词：带状疱疹阿昔洛韦治疗临床应用

Improving the activity of electrochemical reduction of CO_(2) to C_(1) products by oxidation derived copper catalyst

在线全文

学校读者我要写书评

暂无评论

Materials Reports(Energy) 2023年第1期3卷 107-114,I0004页

作者： Lingxue Diao yingda Liu Feifei Chen Hong Pan David Perez de Lara Hui Liu Yahui cheng Feng Luo Department of Electronic Science and Engineering and Tianjin Key Laboratory of Process Control and Green Technology for Pharmaceutical Industry Nankai UniversityTianjin300350China Department of Basic Science Tianjin Agricultural UniversityTianjin300392China IMDEA Nanosci Faraday 9Ciudad Univ CantoblancoMadrid28049Spain Tianjin Key Lab for Rare Earth Materials and Applications Center for Rare Earth and Inorganic Functional MaterialsSchool of Materials Science and EngineeringNankai UniversityTianjin300350China

Cu-based electrocatalysts have become the focus in the field of electrochemical CO_(2) reduction reaction(ECO_(2) RR)due to their ability to produce multicarbon ***,the research on generating single carbon products with higher economic feasibility via ECO_(2) RR based on Cu-based electrocatalysts is rather rare,and the roles of the surface architecture and oxides of the electrocatalysts have not been explained *** this work,a two-step method including thermal oxidation and electroreduction is proposed to introduce Cuþinto pure Cu foil to form Cu_(2)O/Cu *** regulating the surface composition and morphology of the electrocatalyst in this way,the activity of ECO 2 RR to C_(1) products has been greatly *** Faradaic efficiency of carbon products of the Cu_(2)O/Cu electrode reaches 84%at?0.7 V *** with good selectivity for HCOOH and *** current density of Cu_(2)O/Cu electrode reaches-12.21 mA cm^(2) at-0.8 V ***,which is much higher than that of the Cu foil electrode(?0.09 mA cm?2).In-situ Raman characterization shows that Cuþin Cu_(2)O/Cu electrode could inhibit hydrogen generation and promote ECO_(2) RR by stabilizing the adsorption of CO_(2).

关键词： Cu-based electrocatalyst Electroreduction of CO_(2) In-situ Raman spectra C_(1)product

Bandgap prediction by deep learning in configurationally hybridized graphene and boron nitride

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2019年第1期5卷 915-922页

作者： Yuan Dong Chuhan Wu Chi Zhang yingda Liu Jianlin cheng Jian Lin Department of Mechanical&Aerospace Engineering University of MissouriColumbiaMO 65211USA Department of Electrical Engineering&Computer Science University of MissouriColumbiaMO 65211USA

It is well-known that the atomic-scale and nano-scale configuration of dopants can play a crucial role in determining the electronic properties of ***,predicting such effects is challenging due to the large range of atomic configurations that are ***,we present a case study of how deep learning algorithms can enable bandgap prediction in hybridized boron–nitrogen graphene with arbitrary supercell configurations.A material descriptor that enables correlation of structure and bandgap was developed for convolutional neural *** calculated by ab initio calculations,and corresponding structures,were used as training *** trained networks were then used to predict bandgaps of systems with various *** 4×4 and 5×5 supercells they accurately predict bandgaps,with a R^(2) of >90% and root-mean-square error of~0.1 *** transfer learning was performed by leveraging data generated from small supercells to improve the prediction accuracy for 6×6 *** work will pave a route to future investigation of configurationally hybridized graphene and other 2D ***,given the ubiquitous existence of configurations in materials,this work may stimulate interest in applying deep learning algorithms for the configurational design of materials across different length scales.

关键词： materials configuration boron

壁面温度和撞壁距离对柴油喷雾燃烧特性的影响

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

燃烧科学与技术 2023年第4期29卷 373-380页

作者：杨灿李庆旗龚涛成晓北王英达华中科技大学能源与动力工程学院武汉430074 东风商用车技术中心武汉430074

根据撞壁距离L与自由喷雾液相贯穿距L_(liquid)之比,将喷雾撞壁模式分为严重湿壁、轻微湿壁、临界湿壁、未湿壁.通过高温高压定容弹试验和OpenFOAM仿真,研究了高、低壁温条件下,4种喷雾撞壁模式对着火特性、火焰发展特性以及燃油分布特... 详细信息

根据撞壁距离L与自由喷雾液相贯穿距L_(liquid)之比,将喷雾撞壁模式分为严重湿壁、轻微湿壁、临界湿壁、未湿壁.通过高温高压定容弹试验和OpenFOAM仿真,研究了高、低壁温条件下,4种喷雾撞壁模式对着火特性、火焰发展特性以及燃油分布特性的影响.结果表明:提高壁面温度可以促进喷雾着火及燃烧过程,且其促进作用随L/L_(liquid)增大而减小;高壁温条件下,一定程度的喷雾撞壁有利于油气混合和燃烧,低壁温条件下则相反.

关键词：壁面温度撞壁距离燃烧特性定容弹 OpenFOAM

压头角度对点载荷作用下煤岩体内的应力分布影响研究

在线全文

学校读者我要写书评

暂无评论

矿业安全与环保 2023年第3期50卷 1-5,11页

作者：程豪杰邱守强谭桠杰翟英达张玉江太原理工大学矿业工程学院山西太原030024 山东能源临沂矿业集团有限责任公司山东临沂276017 阳城县阳泰集团实业有限公司山西晋城048100 山东能源集团博士后科研工作站山东济南250014

为研究压头角度造成点载荷试验结果差异的原因,采用理论分析和数值模拟方法研究压头角度不同时点载荷作用下煤岩体内部的应力分布规律。研究发现:在不同角度压头作用下煤岩体内部均产生压应力和拉应力;在垂直和水平剖面上,垂直应力分别... 详细信息

为研究压头角度造成点载荷试验结果差异的原因,采用理论分析和数值模拟方法研究压头角度不同时点载荷作用下煤岩体内部的应力分布规律。研究发现:在不同角度压头作用下煤岩体内部均产生压应力和拉应力;在垂直和水平剖面上,垂直应力分别呈现“倒置双峰形”和“圆环状”;加载点附近煤岩体受到各个方向的压应力作用,且随着与加载点距离的增大而减小,在加载点一定距离内受到垂直加载轴方向的水平拉应力和竖直拉应力,水平拉应力区呈圆球状。研究不同角度压头作用下煤岩体的应力状态,发现压头角度对应力分布形式影响较小,但在小角度压头作用下煤岩体内应力集中更加强烈,进而影响煤岩体试样破坏时应力值。

关键词：点载荷压头角度应力分布理论分析数值模拟

固体废物中重金属的固化/稳定化技术研究进展

在线全文

学校读者我要写书评

暂无评论

环境化学 2023年第6期42卷 2032-2047页

作者：曾映达程银汉瞿广飞吴缓缓解若松杨玉益李应丽陈伊婷徐尤枭昆明理工大学环境科学与工程学院昆明650500

含重金属固体废物的大量堆存不仅占用了大量的土地资源,且其中的重金属元素将会在地表径流冲刷、雨水淋溶、风化等作用下浸出从而对周遭环境生态造成巨大威胁.固化;稳定化处理技术能够降低固体废物中重金属的浸出毒性或是生物有效性,是... 详细信息

含重金属固体废物的大量堆存不仅占用了大量的土地资源,且其中的重金属元素将会在地表径流冲刷、雨水淋溶、风化等作用下浸出从而对周遭环境生态造成巨大威胁.固化;稳定化处理技术能够降低固体废物中重金属的浸出毒性或是生物有效性,是应对固体废物重金属环境污染的重要技术手段.本文首先简要介绍了固化;稳定化技术的概念及效果评价方法,再结合近年来相关研究总结了现阶段常用的固化;稳定化技术的研究进展,包括水泥基固化;稳定化技术,地质聚合物基固化;稳定化技术,化学药剂稳定化技术以及微生物诱导矿化稳定化技术.总结了各项技术的优点及存在的不足,并针对未来重金属固化;稳定化技术的发展提出了一定的看法.

关键词：固体废物重金属浸出毒性固化稳定化

维普期刊数据库博看期刊