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A flexible multiscale algorithm based on an improved smoothed particle hydrodynamics method for complex viscoelastic flows

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1387-1402页

作者： Jinlian REN Peirong lu Tao JIANG Jianfeng LIU weigang lu College of Mathematical Science Yangzhou UniversityYangzhou 225002Jiangsu ProvinceChina College of Hydraulic Science and Engineering Yangzhou UniversityYangzhou 225002Jiangsu ProvinceChina

Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic ***,traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time,and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic *** this paper,a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH)and multiscale universal interface(MUI)library is presented for viscoelastic *** proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping *** test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic *** the first example,the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial *** effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping *** the second example,the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD)*** numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping ***,transferring different physical quantities has an important effect on the numerical results.

关键词： multiscale method improved smoothed particle hydrodynamics(SPH) dissipative particle dynamics(DPD) multiscale universal interface(MUI) complex viscoelastic flow

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Numerical Prediction and Performance Experiment in a Deep-well Centrifugal Pump with Different Impeller Outlet Width

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Chinese Journal of Mechanical Engineering 2013年第1期26卷 46-52页

作者： SHI Weidong ZHOU Ling lu weigang PEI Bing LANG Tao National Research Center of Pumps and Pumping System Engineering and Technology Jiangsu UniversityZhenjiang 212013China

The existing research of the deep-well centrifugal pump mainly focuses on reduce the manufacturing cost and improve the pump performance, and how to combine above two aspects together is the most difficult and important topic. In this study, the performances of the deep-well centrifugal pump with four different impeller outlet widths are studied by the numerical, theoretical and experimental methods in this paper. Two stages deep-well centrifugal pump equipped with different impellers are simulated employing the commercial CFD software to solve the Navier-Stokes equations for three-dimensional incompressible steady flow. The sensitivity analyses of the grid size and turbulence model have been performed to improve numerical accuracy. The flow field distributions are acquired and compared under the design operating conditions, including the static pressure, turbulence kinetic energy and velocity. The prototype is manufactured and tested to certify the numerical predicted performance. The numerical results of pump performance are higher than the test results, but their change trends have an acceptable agreement with each other. The performance results indicted that the oversize impeller outlet width leads to poor pump performances and increasing shaft power. Changing the performance of deep-well centrifugal pump by alter impeller outlet width is practicable and convenient, which is worth popularizing in the engineering application. The proposed research enhances the theoretical basis of pump design to improve the performance and reduce the manufacturing cost of deep-well centrifugal pump.

关键词： deep-well centrifugal pump impeller outlet width performance numerical simulation

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Metal-organic frameworks as photocatalysts for aerobic oxidation reactions

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Science China Chemistry 2023年第6期66卷 1634-1653页

作者： Kun Wu Xin-Yi Liu Pei-Wen Cheng Mo Xie weigang lu Dan Li College of Chemistry and Materials Science Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and ApplicationsJinan UniversityGuangzhou 510632China

Metal-organic frameworks(MOFs)are emerging as one of the most intriguing classes of heterogeneous photocatalysts owing to their abundant structures,tunable porosity,and versatile *** advantages of bottom-up design and reticular synthesis render MOF materials with desired photocatalytic properties for targeted *** this review,we discussed the design and synthesis of MOF-based photocatalysts as well as strategies for enhancing photocatalytic *** progress on MOFs as platforms for photocatalytic aerobic oxidation reactions was summarized and categorized according to the types of bond *** hope this review will give an in-depth insight into MOF-based photocatalytic systems for not only aerobic oxidation reactions but also other organic transformations.A brief outlook on the challenges and opportunities of MOFs as heterogeneous photocatalysts is provided at the end of the review.

关键词： metal-organic frameworks heterogeneous photocatalyst reactive oxygen species aerobic oxidation organic synthesis

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Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water

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Frontiers of Environmental Science & Engineering 2012年第2期6卷 171-176页

作者： Xiaoyan MA Shifei HU Hongyu WANG Jun LI Jing HUANG Yun ZHANG weigang lu Qingsong LI Municipal Department of Architecture Engineering College Zhejiang University of TechnologyHangzhou 310014China National Water Quality Monitoring Net of City Water Supply Hangzhou Station Hangzhou 310014China Water Resources and Environmental Institute Xiamen University of TechnologyXiamen 361005China

Metabolites of algae such as geosmin, 2- methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientifc attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. Reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also dis- cussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg. L~ and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant k -- 0.00213 L.（***）-1. Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO4 dosage, but dramatically dropped with the increasing levels of humic acid （1.8-4.5 mg. L-1） and other odor-causing compounds （e.g. fl-cyclocitral, 0-1886.0 pg.L-1）. Solution pH （5.2- 9.0） and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demon- strates that KMnO4 oxidation is an effective option to remove dimethyl trisulfide from water.

关键词： odor and taste oxidation reaction reactionkinetics water treatment

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Polarization engineering in porous organic polymers for charge separation efficiency and its applications in photocatalytic aerobic oxidations

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Science China Chemistry 2024年第3期67卷 1000-1007页

作者： Kun Wu Pei-Wen Cheng Xin-Yi Liu Ji Zheng Xiao-Wei Zhu Mo Xie Puxin Weng weigang lu Dan Li College of Chemistry and Materials Science Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and ApplicationsJinan UniversityGuangzhou 510632China Guangdong Rare Earth Photofunctional Materials Engineering Technology Research Center School of Chemistry and EnvironmentJiaying UniversityMeizhou 514015China

Photocatalytic aerobic oxidation reactions are largely governed by the efficiency of charge separation and subsequent reactive oxygen species(ROS) generation. Herein, we report a polarization engineering strategy to promote the charge separation and ROS generation efficiency by substituting the benzene unit with furan/thiophene in porous organic polymers(POPs). Benefiting from the extent of local polarization, the thiophene-containing POP(JNU-218) exhibits the best photocatalytic performance in aerobic oxidation reactions, with a yield much higher than those for the furan-containing POP(JNU-217) and the benzenecontaining POP(JNU-216). Experimental studies and theoretical calculations reveal that the increase of local polarization can indeed reduce the exciton binding energy, and therefore facilitate the separation of electron-hole pairs. This work demonstrates a viable strategy to tune charge separation and ROS generation efficiency by modulating the dipole moments of the building blocks in porous polymeric organic semiconductors.

关键词： porous organic polymer local polarization photocatalytic aerobic oxidation charge separation reactive oxygen species exciton binding energy

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面向增强现实的点云配准算法

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激光与光电子学进展 2019年第19期56卷 255-261页

作者：陆卫刚周治平江南大学物联网工程学院江苏无锡214122 江南大学物联网技术应用教育部工程研究中心江苏无锡214122

针对增强现实中基于目标点云的跟踪与注册问题,提出一种稳健Z分数混合树的配准算法。通过局部邻域内的点至拟合平面的垂直距离以及沿平面法线点的分布来识别噪点,运用绝对中位差增强Z分数的稳健性,同时,采用混合树算法提高最近点的搜索... 详细信息

针对增强现实中基于目标点云的跟踪与注册问题,提出一种稳健Z分数混合树的配准算法。通过局部邻域内的点至拟合平面的垂直距离以及沿平面法线点的分布来识别噪点,运用绝对中位差增强Z分数的稳健性,同时,采用混合树算法提高最近点的搜索效率。将上述算法应用于增强现实的成像原理中,以对其进行理论论证。分别利用斯坦福大学某研究组的点云数据集和真实采集数据对该算法进行验证。结果表明,在含噪点云集中,该算法能在保持一定精度的同时有效提高配准效率,其用时约为对比算法的5%~10%。

关键词：图像处理点云配准增强现实 Z分数模糊近邻

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非对称性电信网络竞争性均衡的存在性与实践含义

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管理评论 2014年第9期26卷 109-127页

作者：陆伟刚西安邮电大学产业经济研究所西安710061

电信网络非对称是一种常见的市场结构,这也是导致市场频频受到各种管制的原因。本文在标准的LRT1998模型里导入非对称性市场构造的几个基本决定因素并运用双边市场平台的用户需求协调对模型进行拓展性分析,对电信网络非对称竞争均衡的... 详细信息

电信网络非对称是一种常见的市场结构,这也是导致市场频频受到各种管制的原因。本文在标准的LRT1998模型里导入非对称性市场构造的几个基本决定因素并运用双边市场平台的用户需求协调对模型进行拓展性分析,对电信网络非对称竞争均衡的存在性进行了研究。发现,终端接入价格与网络安装基础正向变动关系不明显;用户选择偏好与顾客保留价值直接作用于终端价格与零售价格;呼叫模式与网络外部性间接作用于竞争性均衡的结果;市场两边中单边拥有竞争优势的网间竞争的价格水平等于网间成本。依据这些研究结论,本文给出了在运营商竞争策略设计与政府管制方面的若干应用建议。

关键词：非对称性网络选择偏好竞争性均衡

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水泵及泵装置效率换算方法

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排灌机械工程学报 2012年第6期30卷 677-682,689页

作者：陆伟刚严登丰甄峰扬州大学水利科学与工程学院江苏扬州225009

分析了传统效率换算公式的理论依据和有关标准推荐的效率换算方法,发现传统水泵效率换算式理论具有表达不完整、经验性重、通用性缺乏等问题;比较了由不同换算公式计算得到的最优工况点泵水力损失比,发现Medici式、Fromm式及两种Moody... 详细信息

分析了传统效率换算公式的理论依据和有关标准推荐的效率换算方法,发现传统水泵效率换算式理论具有表达不完整、经验性重、通用性缺乏等问题;比较了由不同换算公式计算得到的最优工况点泵水力损失比,发现Medici式、Fromm式及两种Moody式原模型效率差值较大,其他各式较小,Ackeret式最小.研究提出了泵及泵装置'分部效率换算方法',从流体流动特性出发,介绍了3种不同流动区摩阻系数表达式,提出经数学处理的便于应用的简化公式;从泵内流动特性出发,分析和论证了摩阻系数的确定依据,研究了泵比例系数和摩阻系数对水泵效率换算的影响;推导提出了另一种效率常数计算方法;针对相同的原、模型水泵及泵装置实例,给出不同方法的效率换算结果,分析不同方法差异的原因及适用性.研究结果表明:相较于Ackeret式和Hutton式,泵比例系数对'分部效率换算法'的影响较小;采用'分部效率换算法'时,以任何流动区的公式计算摩阻系数其总效率并无明显差异.

关键词：水泵效率泵装置效率效率常数效率换算

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基于数值模拟的深井离心泵导叶性能分析

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农业工程学报 2011年第9期27卷 38-42页

作者：周岭施卫东陆伟刚江苏大学流体机械工程技术研究中心镇江212013

针对一典型的150QJ20型深井离心泵,分别设计了三维曲面导叶与圆柱形导叶,基于FluENT 6.2软件,采用标准k-ε模型、SIMPLEC算法对分别装配两种导叶的两级深井泵全流场模型进行了数值模拟,获得了导叶内的压力分布和泵的外特性参数。对两种... 详细信息

针对一典型的150QJ20型深井离心泵,分别设计了三维曲面导叶与圆柱形导叶,基于FluENT 6.2软件,采用标准k-ε模型、SIMPLEC算法对分别装配两种导叶的两级深井泵全流场模型进行了数值模拟,获得了导叶内的压力分布和泵的外特性参数。对两种导叶内部的静压变化进行了分析,比较了导叶的压力转换能力。结果显示,三维曲面导叶流道内流动损失较小,具有较高的压力转换能力,装配了三维曲面导叶的泵性能较优。将数值模拟结果与试验结果对比,分析了两者的差异,进而证实了数值模拟结果的准确性,为优化导叶水力性能提供了参考。

关键词：离心泵静力分析计算机模拟导叶静压分布

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运营商用户响应性预期的影响因素分析

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经济与管理研究 2015年第3期36卷 120-126页

作者：常蕾陆伟刚西安邮电大学经济与管理学院硕士研究生西安市710061 西安邮电大学产业经济研究所教授

消费者在选择运营商前会对几个运营商在价格、服务、用户感知等方面做一定的了解,从而形成自己的预期并做出选择。不同的用户预期在不同的市场竞争环境中对平台的定价行为、平台均衡配置及获利能力都有一定影响。本文采用网上发布问卷... 详细信息

消费者在选择运营商前会对几个运营商在价格、服务、用户感知等方面做一定的了解,从而形成自己的预期并做出选择。不同的用户预期在不同的市场竞争环境中对平台的定价行为、平台均衡配置及获利能力都有一定影响。本文采用网上发布问卷与街头随机发放问卷的方法,对380名手机用户做了预期影响因素的问卷调查,应用SPSS与SmartPLS软件对数据进行了信效度分析、路径分析与显著性分析,得出了影响用户预期的因素及影响程度。结合本文分析的结论,为移动互联网运营商进行预期管理提供了建议。

关键词：响应性预期结构方程模型影响因子

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