检索结果-南通市图书馆

EXPERIMENTAL STUDIES ON DYNAMIC PROPAGATION OF CRACKS UNDER BIAXIAL COMPRESSION

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1994年第3期7卷 211-220页

作者： Yu, Hengwen Song, jinliang Feng, Deyi Jian, Chun Univ of Science & Technology of China Hefei China

This paper deals with the initiation and non-coplaner propagation of cracks under biaxial compression. The running process of the propagating cracks is successfully recorded with the method of dynamic photoelasticity. A series of important fracture parameters such as cracks propagating velocity, critical opening loading and initial angle of cracks growth under biaxial compression is calculated. Results show that the stress field in front of the non-closed crack tip under biaxial compression is a mixed-mode singular field, the dynamic propagation of the new tensile cracks is just stable and shows distinct stages, but the unstable crack appears under high loads and results in the rupture of the matrix.

关键词： Failure (mechanical) Fracture Fracture mechanics Loads (forces) Photoelasticity Stability Stresses Velocity

Dynamical analysis of a diffusive malaria model with fixed latent period in the human and vector populations

在线全文

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2023年第1期16卷 209-234页

作者： Hao Qu Tianli Jiang jinliang Wang Jiantao Zhao School of Mathematical Science Heilongjiang University Harbin 150080P.R.China

To investigate the impact of the fixed latent periods in the human and vector populations on the disease transmission in heterogenous environment,we formulate a nonlocal and time-delayed reaction-diffusion(NLTD-RD)*** appealing to the next generation operator(NGO),we define the basic reproduction number(BRN)Ro,and prove it as a threshold parameter for indicating whether disease persists or ***,if o1,the disease is shown to be uniformly *** the homogeneous case that all parameters are assumed to be constants,the explicit expression of o is *** further achieved the global attractivity of the constant equilibria by utilizing Lyapunov *** simulations are performed to verify the theoretical results and the effects of the diffusion rate on disease transmission.

关键词： Nonlocal delays spatial heterogeneity basic reproduction number uniform persistence Lyapunov functionals

DYNAMIC ANALYSIS OF AN SIR MODEL WITH STOCHASTIC PERTURBATIONS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2013年第6期6卷 63-77页

作者： ZHENJIE LIU jinliang WANG YALAN XU GUOQIANG LI Department of Mathematics Harbin University Harbin Heilongjiang 150086 P. R. China School of Mathematical Science Heilongjiang University Harbin Heilongjiang 150080 P. R. China

In this paper, we present a differential infectivity SIR epidemic model with modified saturation incidences and stochastic perturbations. We show that the stochastic epidemic model has a unique global positive solutio... 详细信息

关键词： Epidemiological model Ito's formula stochastic Lyapunov function asymptotic behavior.

How do the non-linear I-V curves of ZnO-based adaptive composites behave with electrodes placed on the opposite sides with a series of horizontal distances?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2024年第5期9卷 981-988页

作者： Ya Sun Zhikang Yuan Zhiwen Huang Jun Hu jinliang He Qi Li State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijingChina 2School of Electronic and Information EngineeringTongji UniversityShanghaiChina

Recently,ZnO-based composites have been widely applied in the field of electric *** meet the diverse application requirements,it is necessary to figure out the I-V characteristics of ZnO composites whose high-voltage and ground-voltage electrodes are arranged on the opposite sides with a certain horizontal distance.30 vol%,40 vol%and 50 vol%ZnO-based silicone rubber composites were *** horizontal distance between their electrodes was set as 50,100,500μm,1 and 2 mm,*** showed that with the increase of ZnO fillers volume fraction under a fixed horizontal distance of 100μm,from 30 vol%to 50 vol%,the I-V curves shifted left,the leakage current increased and the switching voltage *** the horizontal distance between electrodes increased from 50μm to 1 mm under a fixed doping concentration of 40%,the I-V curves shifted to the right,the leakage current dropped and the switching voltage *** mathematical and physical models were established to explain the *** work provides a referential significance for the practical application of ZnO composites,such as 5G folding mobile phones and power electronic modules.

关键词： composites rubber linear

Prediction method for energy con sumption per ton of fused magnesium furnaces using data driven and mechanism model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Control Theory and Technology 2019年第1期17卷 24-36页

作者： Dan GUO Zhiwei WU Tianyou CHAI Jie YANG jinliang DING State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang Liaoning 110819 China National Engineering Research Center of Metallurgical Automation (Shenyang) Shenyang Liaoning 7 70879 China

The electric energy consumed in every ton of acceptable product, namely energy consumption per ton (ECT), is an important overall index for the production process of a fused magnesium furnace. The furnace is the equipment for producing the fused magnesia. The ECT value depends on the current in the smelting process. The optimal operation for a fused magnesium furnace is supposed to have the ECT as low as possible, where the key is to predict ECT accurately. By introducing an unknown high-order non linear term, this paper builds a dynamic ECT model for differe nt production batches based on the static ECT model for one batch. The average current is taken as the input of the dynamic ECT model, which is composed of the unknown high-order nonlinear term and a nonlinear model with unknown parameters. The order of the nonlinear term is determined by the distance correlatio n and the nonlinear term is estimated by the stochastic con figuration n etwork, while the parameters of the non linear model is ide ntified by the least square method. The estimation of the nonli near term alter nates with the parameter identification. This paper proposes a prediction method for ECT, which is composed of the order identification of the non linear term, the alternating identification of the model and the ECT prediction model. The simulation experiments are conducted by the on-site data, and the results verify the effectiveness of the proposed prediction method.

关键词： Fused magnesia energy consumption per ton alternating identification stochastic configuration network distance correlation

Effect of flapping trajectories on the dragonfly aerodynamics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2006年第7期51卷 777-784页

作者： XU jinliang ZHAO Chuangxin ZHANG Yongli ZHANG Yang Micro Energy System Laboratory Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 510640 China Graduate School of Chinese Academy of Sciences Beijing 100039 China Department of Mechanical Engineering Aerospace and Manufacturing Division University of Manchester 561000 UK

The effects of translational, figure-eight and double-figure-eight flapping trajectories on the dragonfly aerodynamics were numerically studied by solving the Navier-Stokes equations. There is a common characteristic regarding the lift/drag force coefficients that the downstroke flapping provides the lift forces while the upstroke flapping creates the thrust forces for different flapping trajectories. The maximum lift force coefficient exceeds five for the translational trajectory. It is greater than six for the figure-eight and double-figure-eight flapping trajecto- ries, which is sufficiently larger than unity under the steady state flight condition. The ellipse and dou- ble-figure-eight flapping trajectories yield the de- crease of the lift force, while the figure-eight flapping trajectory yields higher lift force as well as the thrust force than the translational flapping one. During the insect flight, the wing flapping status should be changed instantaneously to satisfy various require- ments. Study of the flapping trajectories on the insect aerodynamics is helpful for the design of the Mi- cro-air-vehicles (MAVs).

关键词：蜻蜓升力曳力空气动力学 CFD 计算流体力学

Rational synthesis of chitin-derived nitrogen-doped porous carbon nanofibers for efficient polysulfide confinement

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第6期16卷 8478-8487页

作者： Shanfeng Yang Shuiping Luo Xinji Dong Li Tian Pei Kang Shen jinliang Zhu School of Resources Environment and MaterialsCollaborative Innovation Centre of Sustainable Energy MaterialsCollege of Chemistry and Chemical EngineeringGuangxi UniversityNanning 530004China Department of Chemistry and Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology(SUSTech)Shenzhen 518055China Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion Hunan University of Science and TechnologyXiangtan 411201China

Principles of inexpensive biotechnology are being increasingly used to address the problems posed by the use of lithium-sulfur *** used chitin,a low-cost marine biowaste product,as a precursor for the in-situ preparation of chitin-derived nitrogendoped hierarchical porous carbon fibers(CNHPCFs)containing abundant *** materials are characterized by varying morphologies and high specific surface areas and present a hierarchical porous *** adsorb polysulfides,exhibit good ionic conductivity,and can be potentially used to generate green *** properties help address the problems of volume expansion and slow *** CNHPCF-1@S cathode exhibits excellent cycling performance and high capacity(1368.80 mAh·g^(−1)at 0.2 C;decay rate:0.011%per turn at 5 C).The high electrochemical reversibility recorded for CNHPCF-1@S and the stepwise reaction mechanism followed were studied using the in-situ X-ray diffraction and in-situ Raman spectroscopy *** results reported herein can potentially help develop new ideas for the recycling and treatment of marine *** results can also provide a platform to improve the application prospects of lithium-sulfur batteries.

关键词： chitin carbon fiber Li-S battery in-situ Raman in-situ X-ray diffraction

Analysis of rainfall runoff characteristics from a subtropical urban lawn catchment in South-east China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2012年第4期6卷 531-539页

作者： jinliang HUANG Zhenshun TU Pengfei DU Qingsheng LI Jie LIN Environmental Science Research Center Xiamen UniversityXiamen 361005China Department of Environmental Science and Engineering Tsinghua UniversityBeijing 100084China Fujian Institute of Oceanography Xiamen 361012China

Characteristics of rainfall runoff from a 3.26 hm^2 urban catchment with predominant land-use as lawn in Xiamen City, South-east China were investigated and analyzed. Water quality and quantity measurements of rainfall runoff were conducted for ten rainfall events over the period March, 2008 to April, 2009. The results indicated that chemical oxygen demand （COD） and total phosphorus （TP） were the major pollutants with event mean concentrations of 56.09 and 0.44mg.L^-1. From hydrograph and pollutograph analysis of two typical rainfall events, it was clear that the peak rainfall preceded the peak flowrate by about 15-20 min. Meanwhile, concentrations of major pollutants showed multiple peaks and these peaks usually preceded peak flowrate. There were no distinctive first-flush effects except for the rainfall events with the longest rainfall duration and largest runoff volume, which was verified by the fact that the first 30% runoff volume （FF30） carried 39.36% of the total suspended solids （TSS） load, 35.17% of the COD load, 28.13% of the TP load and 39.03% of the nitrate nitrogen load. Multivariate regression analysis further demonstrated that the total runoffvolume had a positive correlation with the FF30 of TSS and COD.

关键词： rainfall runoff first flush pollution characteristics urban lawn catchment

Fractal model of lightning channel for simulating lightning strikes to transmission lines

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第11期52卷 3135-3141页

作者： HE jinliang ZHANG XueWei DONG Lin ZENG Rong LIU ZeHong Department of Electrical Engineering Tsinghua UniversityBeijing 100084China Department of UHV Construction State Grid Corporation of ChinaBeijing 100031China

How to accurately evaluate the direct-strike lightning protection is one of the key issues in the design of transmission lines. In this paper, three important issues in applying the fractal simulation to the lightning protection of transmission lines were discussed, including the criteria and implementation of upward leader inception, the connection with the magnitude of lightning current, and the calculation and control of fractal dimensions. Then we conducted the simulation iterately, leading to statistical results, which indicate that even if the transmission line satisfies the perfect shielding condition, shielding failure fault remains possible. Furthermore, we calculated the shielding failure fault rates of an EHV line with different ground obliquities and distribution of strike points over the interval between two neighboring towers along a UHV-DC line to find out the weak point of transmission-line lightning protection. This work provides a promising approach for improving the lightning protection property of transmission lines by optimizing the configuration of shielding wires and phase or pole conductors.

关键词： lightning shielding failure transmission line fractal theory dielectric breakdown model electrogeometric model