检索结果-南通市图书馆

随机纤维膜过滤器捕集浮游生物颗粒的DPM数值模拟

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

湖南工业大学学报 2025年第2期39卷 15-21页

作者：邱显焱郑静湖南工业大学机械工程学院湖南株洲412007

目前常用的深海浮游生物取样方法,是采用水泵抽取海水,并通过过滤技术捕捉其中的浮游生物。因此,以浮游生物过滤器为研究对象,通过随机算法建立三维纤维膜微观模型,并基于相似准则对纤维膜模型进行数值模拟研究,同时,采用拉格朗日离散... 详细信息

目前常用的深海浮游生物取样方法,是采用水泵抽取海水,并通过过滤技术捕捉其中的浮游生物。因此,以浮游生物过滤器为研究对象,通过随机算法建立三维纤维膜微观模型,并基于相似准则对纤维膜模型进行数值模拟研究,同时,采用拉格朗日离散相模型(DPM)追踪浮游生物颗粒在过滤器内的运动轨迹。研究结果表明:入口速度的变化对流场的压力和速度分布有显著影响,随着入口速度增加,流场内部速度差增大,流场中的压力分布出现明显的分层现象,且压力损失随入口速度增大而增大。其孔隙较小的纤维模型具有更好的过滤性能,对浮游生物颗粒的过滤效率基本稳定在80%。

关键词：浮游生物纤维滤膜数值模拟 DPM 捕集效率

Sand particle dislodgement in windblown sand

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第6期30卷 910-916页

作者： Tian-Li Bo zheng Li Xiao-jing zheng Key Laboratory of Mechanics on Western Disaster and Environment Lanzhou University Department of Mechanics Lanzhou University School of Electronical and Machanical Engineering Xidian University

The incipient motion of sand particle from sand bed plays a very important role in the prediction of windblown *** this paper,we proposed a new method for predicting the incipient motion of sand particle based on wind speed fluctuation as follows,when the wind speed is larger than the critical wind speed,if the total impulse on sand particle is larger than the critical impulse,incipient motion of sand particle would take place,otherwise if ***,from the analysis of entrainment in the rolling and lifting modes,we come to the following *** the average wind speed is smaller than the critical wind speed,if the average wind speed is used to judge the incipient motion of sand particle,one will underestimate the number of sand particles jumping from the bed,if the instantaneous wind speed is used to judge incipient motion of sand particle,one will overestimate the number of sand particles jumping from the bed;When the average wind speed is larger than the critical wind speed,either the average or the instantaneous wind speeds is used to judge the incipientmotion of sand particles,one will overestimate the number of sand particles jumping from the bed.

关键词： Incipient motion Rolling mode Average wind speed Total impulse Windblown sand

Thermoelastic topology optimization for structures with temperature-dependent material properties

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第12期66卷 3488-3503页

作者： zheng jing RONG XuanPei JIANG Chao State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body School of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

A thermoelastic topology optimization is proposed for structures with temperature-dependent material *** from the common assumption of constant material properties in traditional thermoelastic topology optimization,the temperaturedependent material properties related to mechanical and thermal fields are taken into *** non-uniform temperature distribution of the structure is a design dependent field that may vary during the optimization,and the nonlinear heat transfer analysis is considered according to the large temperature *** on these,a thermoelastic topology optimization model considering temperature-dependent material properties is *** sensitivities with respect to the design variables are derived and the Method of Moving Asymptotes(MMA)algorithm is used to update the topological design variables.A cooperation platform based on MATLAB and ABAQUS is developed for the proposed thermoelastic topology optimization method to deal with problems with arbitrary domains for the design of complex engineering *** typical numerical examples are given to illustrate the effectiveness of the proposed method and show the important influence of the temperaturedependent material properties.

关键词： thermoelastic topology optimization nonlinear heat transfer temperature-dependent material properties

The Periodic Solutions of a Nonhomogeneous String with Dirichlet-Neumann Condition

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2014年第4期35卷 619-632页

作者： Changqing TONG jing zheng Department of Mathematics Hangzhou Dianzi University

This paper deals with the existence of periodic solutions of a nonhomogeneous string with Dirichlet-Neumann condition. The authors consider the case that the period is irrational multiple of space length and prove that for some irrational number, zero is not the accumulation point of the spectrum of the associated linear operator. This result can be used to prove the existence of the periodic solution avoid using Nash-Moser iteration.

关键词： Nonhomogeneous string Periodic solutions Weak solution Continuedfraction Lagrange constant

Dynamic Case Retrieval Method With Subjective Preferences and Objective Information for Emergency Decision Making

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2018年第3期5卷 749-757页

作者： jing zheng Yingming Wang Shengqun Chen Fuzhou University Fujian 350116 China Fujian Jiangxia University Fujian 350108 China School of Electronics Information Science Fujian Jiangxia University Fujian 350108 China

Case-based reasoning(CBR) is one of the best methods for generating an effective solution in an emergency. In recent years, some methods for generating emergency alternatives have been included in practical CBR applications, but there have been no in-depth studies of these processes. In this study,we propose a new method for dynamic case retrieval with subjective preferences and objective information, which considers the personal preferences of the decision makers and changes in the attributes of the emergency as the situation develops. First,we present a formula for calculating the case similarity and changing trends in the case considered, where similar cases are obtained. Next, we describe a method for measuring the overall assessment value with respect to similar historical cases, which is obtained by aggregating the case similarity, the utility case similarity, the first response time, and the implementation *** subjective preferences and objective information are also integrated in the decision-making process. Finally, we present a case study based on the emergency response to a fire in a highrise building, which illustrates the applicability and feasibility of the proposed method.

关键词： Case-based reasoning(CBR) dynamic case retrieval pairwise comparison matrix preference relation weight estimation

Expansion modelling of discrete grey model based on multi-factor information aggregation

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2014年第5期25卷 833-839页

作者： Naiming Xie Chaoyu Zhu jing zheng College of Economics and Management Nanjing University of Aeronautics and Astronautics

This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h variables grey forecasting model （GM （1, h））, always aggregate the main system variable and independent variables in a linear form rather than a nonlinear form, while a nonlinear form could be used in more cases than the linear form. And the nonlinear form could aggregate collinear independent factors, which widely lie in many multi-factor forecasting problems. To overcome this problem, a new approach, named as the Solow residual method, is proposed to aggregate independent factors. And a new expansion model, feedback multi-factor discrete grey forecasting model based on the Solow residual method （abbreviated as FDGM （1, h））, is proposed accordingly. Then the feedback control equation and the parameters＇ solution of the FDGM （1, h） model are given. Finally, a real application is used to test the modelling accuracy of the FDGM （1, h） model. Results show that the FDGM （1, h） model is much better than the nonhomogeneous discrete grey forecasting model （NDGM） and the GM （1, h） model.

关键词： multi-variable system Solow residual method dis crete grey forecasting model grey system theory (GST).

Effects of carnosine on the evoked potentials in hippocampal CA1 region

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第7期10卷 505-511页

作者： Zhou-yan FENG Xiao-jing zheng jing WANG Key Lab of Biomedical Engineering of Ministry of Education College of Biomedical Engineering and lnstrument Science Zhejiang University Hangzhou 310003 China

Objective： To directly examine the effects ofcarnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods： Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results： In both orthodromic and antidromic response potentials, carnosine transformed population spikes （PSs） with single spike into epileptiform multiple spikes. In addition, similar to the effect of 7-aminobutyric acidA （GABAA） antagonist picrotoxin, camosine decreased paired-pulse stimulating depression significantly. However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion： The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.

关键词： Carnosine Hippocampus Evoked potential Epileptic seizure

The Fractal Dimensions of the Level Sets of the Generalized Iterated Brownian Motion

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2013年第3期29卷 597-602页

作者： Chang-qing TONG zheng-yan LIN jing zheng Institute of applied mathematics Hangzhou Dianzi University Department of Mathematics Zhejiang University

Let{W1（t）, t∈R＋} and {W2（t）, t∈R＋} be two independent Brownian motions with W1（0） = W2（0） = 0. {H （t） = W1（｜W2（t）｜）, t ∈R＋} is called a generalized iterated Brownian motion. In this paper, the Ha... 详细信息

关键词： Hausdorff dimension packing dimension local time generalized iterated Brownian motion

GPU-acceleration 3D rotated-staggered-grid solutions to microseismic anisotropic wave equation with moment tensor implementation

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2023年第4期33卷 403-410页

作者： jing zheng Lingbin Meng Yuan Sun Suping Peng State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China College of Geoscience and Surveying Engineering China University of Mining and Technology-BeijingBeijing 100083China

To improve the accuracy of microseismic inversion,seismic anisotropy and moment tensor source should be carefully considered in the forward modelling *** this study,3D microseismic anisotropy wave forward modelling with a moment tensor source was *** modelling was carried out based on a rotated-staggered-grid(RSG)*** contrast to staggered-grids,the RSG scheme defines the velocity components and densities at the same grid,as do the stress components and elastic ***,the elastic moduli do not need to be *** addition,the detailed formulation and implementation of moment-tensor source loaded on the RSG was presented by equating the source to the stress ***,the RSG-based 3D wave equation forward modelling was performed in parallel using compute unified device architecture(CUDA)programming on a graphics processing unit(GPU)to improve its *** simulations including homogeneous and anisotropic models were carried out using the method proposed in this paper,and compared with other methods to prove the reliability of this ***,the high efficiency of the proposed approach was *** results show that the computational efficiency of proposed method can be improved by about two orders of magnitude compared with traditional central processing unit(CPU)computing *** could not only help the analysis of microseismic full wavefield records,but also provide support for passive source inversion,including location and focal mechanism inversion,and velocities inversion.

关键词： Microseismic Forward modelling Seismic anisotropy Moment tensor