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Biomechanical Models and Experi ments in Bone Tissue Engineering
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作者 Christian ODDOU Julien PIERRE +1 位作者 Karim OUDINA Hervé PETITE 《生物医学工程学杂志》 EI CAS CSCD 北大核心 2005年第S1期11-12,共2页
关键词 Biomechanical Models and Experi ments in Bone Tissue Engineering
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Anomalous crustal movements before great Wenchuan earthquake observed by GPS 被引量:10
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作者 Gu Guohua Meng Guojie Wang Wuxing 《Geodesy and Geodynamics》 2011年第2期13-22,共10页
Studies of GPS data carried out before and after the great Wenchuan earthquake of Ms8.0 on May 12, 2008 show that anomalous crustal movements occurred before the earthquake. Data from 4 pre-earthquake observation sess... Studies of GPS data carried out before and after the great Wenchuan earthquake of Ms8.0 on May 12, 2008 show that anomalous crustal movements occurred before the earthquake. Data from 4 pre-earthquake observation sessions at a dense network of stations show that there were prominent broad-ranged long- and midterm anomalies in horizontal displacements and strain and in vertical displacements. Data from the fewer-numbered reference stations of continuous GPS observations since 1999 in West and South China showed short-term preseismic anomalies in horizontal displacements. The detection of co-seismic horizontal displacements at these stations supports the existence of the pre-earthquake anomalies. Results of single-epoch solutions of data from continuous-observation stations near the epicenter also show large imminent anomalies in vertical displacements. Although the Wenchuan earthquake was not predicted, these results give a strong indication that GPS should be the main observation technique for long-term, mid-term, short-term and imminent earthquake predictions. 展开更多
关键词 Wenchuan earthquake earthquake prediction GPS crustal movement horizontal displace- ment vertical displacement
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Design of Collaborative Platform on Clustering Applications for Governments
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作者 Xuewang ZHANG Zhoujun LI Wei SHEN 《Intelligent Information Management》 2009年第1期30-35,共6页
Collaborative platform on clustering applications for governments consists of six large-scale systems, including the clustering Government Internet portal system, clustering public-mailboxes collaboration system, clus... Collaborative platform on clustering applications for governments consists of six large-scale systems, including the clustering Government Internet portal system, clustering public-mailboxes collaboration system, clustering government affairs portal system, clustering emergency information collaboration system, clustering office automation collaboration system, and clustering messages collaboration systems. The appli-cation and technology architectures of the collaborative platform are elaborated in this paper,and the major key technologies on the platform are also expounded, which includes realization of many governments ap-plications’ scale integration and collaborative application, business model driven software development plat-form based on SOA, SSO, tans-departmental and cross-level multi-engine clustering protocol. Based on the &quot;clustering application&quot;design, to maximize the utilization of hardware, software resources and administra-tive resources of the provincial government collaborative platform, rural districts and counties can build their own platforms based on the provincial platform. The platform having been running for over 2 years shows that planning of urban and rural e-governments’ construction and maintenance is achieved, thus reducing costs greatly and improving governments’ functions. 展开更多
关键词 CLUSTERING APPLICATIONS COLLABORATIVE APPLICATIONS single SIGN on COMPONENTS e-govern- ment
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On Higher Order Pyramidal Finite Elements
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作者 Liping Liu Kevin B.Davies +1 位作者 Michal Krızek Li Guan 《Advances in Applied Mathematics and Mechanics》 SCIE 2011年第2期131-140,共10页
In this paper we first prove a theorem on the nonexistence of pyramidal polynomial basis functions.Then we present a new symmetric composite pyramidal finite element which yields a better convergence than the nonsymm... In this paper we first prove a theorem on the nonexistence of pyramidal polynomial basis functions.Then we present a new symmetric composite pyramidal finite element which yields a better convergence than the nonsymmetric one.It has fourteen degrees of freedom and its basis functions are incomplete piecewise triquadratic polynomials.The space of ansatz functions contains all quadratic functions on each of four subtetrahedra that form a given pyramidal element. 展开更多
关键词 Pyramidal polynomial basis functions finite element method composite elements three-dimensional mortar elements.
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基于随机因子法的随机结构动力特性分析研究 被引量:2
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作者 王小兵 陈建军 +1 位作者 李金平 刘国梁 《振动与冲击》 EI CSCD 北大核心 2008年第2期4-7,共4页
将随机物理参数结构系统的质量矩阵和刚度矩阵均以随机因子的齐次形式表示,通过对QR变换法求解随机矩阵特征值过程的论述,证明了系统中各阶固有频率具有相同的随机因子,并导出了求解固有频率随机变量概率密度的公式;在此基础上,论述了... 将随机物理参数结构系统的质量矩阵和刚度矩阵均以随机因子的齐次形式表示,通过对QR变换法求解随机矩阵特征值过程的论述,证明了系统中各阶固有频率具有相同的随机因子,并导出了求解固有频率随机变量概率密度的公式;在此基础上,论述了系统正则振型矩阵中各元素亦具有相同的随机因子,并导出了求解正则振型随机因子概率密度的公式。通过算例及与Monte Carlo数值模拟结果的对比,验证了文中求解方法和所得结论的正确性。 展开更多
关键词 随机因子 动力特性 QR方法 Mente CARLO方法
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EFFICIENT NUMERICAL METHOD FOR DYNAMIC ANALYSIS OF FLEXIBLE ROD HIT BY RIGID BALL 被引量:1
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作者 徐春铃 王鑫伟 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第4期338-344,共7页
Impact dynamics of flexible solids is important in engineering practice. Obtaining its dynamic response is a challenging task and usually achieved by numerical methods. The objectives of the study are twofold. Firstly... Impact dynamics of flexible solids is important in engineering practice. Obtaining its dynamic response is a challenging task and usually achieved by numerical methods. The objectives of the study are twofold. Firstly, the discrete singular convolution (DSC) is used for the first time to analyze the impact dynamics. Secondly, the efficiency of various numerical methods for dynamic analysis is explored via an example of a flexible rod hit by a rigid ball. Three numerical methods, including the conventional finite element (FE) method, the DSC algorithm, and the spectral finite element (SFE) method, and one proposed modeling strategy, the improved spectral finite element (ISFE) method, are involved. Numerical results are compared with the known analytical solutions to show their efficiency. It is demonstrated that the proposed ISFE modeling strategy with a proper length of con- ventional FE yields the most accurate contact stress among the four investigated models. It is also found that the DSC algorithm is an alternative method for collision problems. 展开更多
关键词 impact dynamics finite element method discrete singular convolution algorithm spectral finite ele- ment method
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Variety Test on Low Temperature-resistant Pleurotus ostreatus Strains in Beijing Area
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作者 张玉铎 郭永杰 +2 位作者 张东雷 彭杏敏 李红红 《Agricultural Science & Technology》 CAS 2016年第5期1037-1040,1045,共5页
With 7 familiar Pleurotus ostreatus strains in Beijing region as the test materials,the randomized block design method was adopted to analyze the antagonistic effects,mycelial growth rate,yield of mushroom at low temp... With 7 familiar Pleurotus ostreatus strains in Beijing region as the test materials,the randomized block design method was adopted to analyze the antagonistic effects,mycelial growth rate,yield of mushroom at low temperature season,total biological efficiency and agronomic characteristics of fruit bodies.The results showed that there were antagonistic effects and differences in all the tested items between all the tested strains,of which the strain PL5 had the shortest spawn age,the strain PL3 showed the highest total biological efficiency,and the fructification of the strain PL7 tasted crisp and tender. 展开更多
关键词 Pleurotus ostreatus Low temperature resistance Comparative experi ment
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Monte Carlo方法在聚合物共混体系界面性质计算机模拟中的应用
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作者 杨浩 杨陟卓 《工程塑料应用》 CAS CSCD 北大核心 2016年第12期141-144,共4页
主要综述了Monte Carlo方法在均聚物共混界面性质、嵌段共聚物与其它聚合物共混界面性质、接枝共聚物与其它聚合物共混界面性质计算机模拟中的应用研究进展。增容剂与共混组分之间的相互作用在很大程度上影响着共混材料的相容性,合适的... 主要综述了Monte Carlo方法在均聚物共混界面性质、嵌段共聚物与其它聚合物共混界面性质、接枝共聚物与其它聚合物共混界面性质计算机模拟中的应用研究进展。增容剂与共混组分之间的相互作用在很大程度上影响着共混材料的相容性,合适的界面性质有助于共混材料应用性能,利用Mente Carlo方法对共混体系中的界面性质进行研究,可以大大简化研究过程,探寻最佳共混条件。 展开更多
关键词 聚合物共混 界面性质 二元共混 三元共混 Mente CARLO方法
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从“声音”到“supplément”
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作者 方向红 《现代哲学》 CSSCI 北大核心 2002年第4期96-100,108,共6页
“supplemént”(“充替”)是解构理论的重要支柱。本文试图从时间性和符号学理路出发完整地重构德里达从对“声音”的解构向“supplément”原理的过渡。同时本文也力求证明,德里达的这种过渡与对胡塞尔符号理论的挪用、引申... “supplemént”(“充替”)是解构理论的重要支柱。本文试图从时间性和符号学理路出发完整地重构德里达从对“声音”的解构向“supplément”原理的过渡。同时本文也力求证明,德里达的这种过渡与对胡塞尔符号理论的挪用、引申和误读是密不可分的。 展开更多
关键词 声音 supplément 超越 触发
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2012年庐江县居民主要死因Fulfillment指数分析
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作者 宋红兵 洪光烈 左登敏 《中国农村卫生》 2015年第7期67-67,69,共2页
目的:探讨庐江县2012年不同年龄组人群某死因对居民期望寿命的影响程度。方法:根据Prifhis Das Gupta等提出的Fulfilment指数法,对2012年庐江县居民死因监测资料进行分析。结果:2012年庐江县0岁组人群损伤与中毒和呼吸系统疾病对潜... 目的:探讨庐江县2012年不同年龄组人群某死因对居民期望寿命的影响程度。方法:根据Prifhis Das Gupta等提出的Fulfilment指数法,对2012年庐江县居民死因监测资料进行分析。结果:2012年庐江县0岁组人群损伤与中毒和呼吸系统疾病对潜在寿命的影响最大,其Fulfil ment指数分别为3.73和6.22;1~39岁年龄段去意外死亡的Fulfil ment指数较高;2012年庐江县居民去恶性肿瘤的Fulfil ment指数在40~60岁年龄段较高;脑血管病自35~岁组后Fulfillment指数大致呈现逐年升高趋势。结论:通过运用Fulfillment指数分析,可以说明各种死因对各年龄组段人口寿命的影响程度,提示某死因防治的重点时期,对提高居民寿命有积极作用。 展开更多
关键词 主要死因 Fulfil ment指数分析
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How Efficient Is China"s Industrial Relocation from East to West? - Evidence from 20 Manufacturing Industries
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作者 周勤 周世军 《China Economist》 2013年第5期109-125,共17页
With the acceleration of the rise of central China and the western development drive, industrial relocation from China's eastern region to the central and western regions is in full swing. However, does the relocatio... With the acceleration of the rise of central China and the western development drive, industrial relocation from China's eastern region to the central and western regions is in full swing. However, does the relocation demonstrate industrial clustering effect? Empirical studies based on twenty two-digit manufacturing industries in 27provinces from 2000 to 2009 demonstrate that industrial clustering effect appeared in central and western regions which had undertaken industrial relocation from eastern region; however, the studies do not show excessive administrative interference as evidenced by the significantly improved productivity of the relocated industries. Compared with non-labor- intensive manufacturing industries, labor-intensive manufacturing industries are easier to form cyclic accumulative effects. Studies also revealed that improvement in supporting infrastructure, industrial chain and higher labor quality in non-agriculture employment during urbanization are significant for central and western regions to undertake industrial relocation. 展开更多
关键词 industrial relocation AGGLOMERATION returns to scale Generalized Method of ments (GMM)
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The Impact of Diferent Vertical Difusion Schemes in a Three-Dimensional Oil Spill Model in the Bohai Sea 被引量:10
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作者 李燕 朱江 王辉 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第6期1569-1586,共18页
Vertical transport is critical to the movement of oil spills in seawater. Breaking waves play an important role by developing a well-defined mixing layer in the upper part of the water column. A three-dimensional (3-... Vertical transport is critical to the movement of oil spills in seawater. Breaking waves play an important role by developing a well-defined mixing layer in the upper part of the water column. A three-dimensional (3-D) Lagrangian random walk oil spill model was used here to study the influence of sea surface waves on the vertical turbulence movement of oil particles. Three vertical diffusion schemes were utilized in the model to compare their impact on oil dispersion and transportation. The first scheme calculated the vertical eddy viscosity semi-empirically. In the second scheme, the vertical diffusion coefficient was obtained directly from an Eulerian hydrodynamic model (Princeton Ocean Model, POM2k) while considering wave- caused turbulence. The third scheme was formulated by solving the Langevin equation. The trajectories, percentages of oil particles intruding into water, and the vertical distribution structures of oil particles were analyzed for a series of numerical experiments with different wind magnitudes. The results showed that the different vertical diffusion schemes could generate different horizontal trajectories and spatial distributions of oil spills on the sea surface. The vertical diffusion schemes caused different water-intruding and resurfacing oil particle behaviors, leading to different horizontal transport of oil particles at the surface and subsurface of the ocean. The vertical diffusion schemes were also applied to a realistic oil spill simulation, and these results were compared to satellite observations. All three schemes yielded acceptable results, and those of the third scheme most closely simulated the observed data. 展开更多
关键词 oil spill Lagrangian random walk Langeven equation oil particles vertical turbulence move- ment
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高亮度电子束相空间重建技术的实验研究
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作者 于清林 张猛 +1 位作者 谷端 赵明华 《核技术》 CAS CSCD 北大核心 2018年第3期13-19,共7页
束团相空间是描述加速器中束流运行状态的重要参数,了解相空间的真实分布对于加速器设计、束团操纵具有非常重要的意义,利用相空间重建技术能够直观地得到束团二维相空间分布。本文结合计算机断层扫描技术(Computer Tomography,CT)与归... 束团相空间是描述加速器中束流运行状态的重要参数,了解相空间的真实分布对于加速器设计、束团操纵具有非常重要的意义,利用相空间重建技术能够直观地得到束团二维相空间分布。本文结合计算机断层扫描技术(Computer Tomography,CT)与归一化相空间理论,在理论推导和模拟验证的基础上,分别利用MENT(Maximum Entropy)算法和FBP(Filtered Back Projection)算法在上海X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser facility,SXFEL)专用束测段(BI1)对电子束团的横向归一化相空间进行重建。通过重建算法变换得到电子束团的真实相空间分布,并对重建结果进行对比和误差分析。实验结果表明,MENT算法能够精确测量电子束团横向相空间分布。 展开更多
关键词 归一化相空间 相空间重建 MENT算法 上海X射线自由电子激光装置
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Effect of Nitrogen Application on Grain Filling in Maize with Different Nitrogen Efficiency
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作者 黄彦凯 申丽霞 李婷 《Agricultural Science & Technology》 CAS 2015年第7期1440-1446,共7页
There are significant differences in nitrogen absorption and utilization effi- ciency among different maize varieties. So it is very essential to determine nitrogen efficiencies of different maize varieties. The effec... There are significant differences in nitrogen absorption and utilization effi- ciency among different maize varieties. So it is very essential to determine nitrogen efficiencies of different maize varieties. The effect of nitrogen application on maize growth can be reflected at the grain filling stage. Many scholars have researched the differences in grain filling characteristics among different maize varieties under the same nitrogen application conditions, but there are reare reports on the differ- ences under different nitrogen application conditions. In this study, the grain filling dynamics of maize were observed so as to determine the differences in nitrogen efficiency and to further compare the differences in grain filling characteristics a- mong different maize varieties. The test was carried out with Tunyu 99, Luyu 19 and Xianyu 335 as the materials during May 1st to October 7th, 2013. Under the nitrogen application levels of NO (0 kg/hm2 of pure nitrogen), N1 (140 kg/hm2 of pure nitrogen) and N2 (210 kg/hm2 of pure nitrogen), the filling dynamics of upper- and middle- lower-part grains of spring maize were studied. The results showed that among the three nitrogen application level, the grain fresh weight and dry weight of Tunyu 99 ranked as N2〉NI〉N0; the grain fresh weight and dry weight of Luyu 19 ranked as N1〉N2〉N0; the grain fresh weight and dry weight of Xianyu 335 ranked as (N1, N2)〉N0, and there was no significant difference between N1 and N2. Un- der the nitrogen application level of N1, Luyu 19 showed the best growth; under the nitrogen application level of N2, Tunyu 99 showed the best growth, The growth ad- vantage of Xianyu 335 was unobvious under neither N1 nor N2 nitrogen application levels. The development-promoting effect of nitrogen application was more obvious in upper-part grains than that in middle-lower-part grains. 展开更多
关键词 Nitrogen fertilizer MAIZE Nitrogen efficiency Grain filling Grain develop- ment
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Resource allocation optimization of equipment development task based on MOPSO algorithm 被引量:8
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作者 ZHANG Xilin TAN Yuejin and YANG Zhiwei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第6期1132-1143,共12页
Resource allocation for an equipment development task is a complex process owing to the inherent characteristics,such as large amounts of input resources,numerous sub-tasks,complex network structures,and high degrees ... Resource allocation for an equipment development task is a complex process owing to the inherent characteristics,such as large amounts of input resources,numerous sub-tasks,complex network structures,and high degrees of uncertainty.This paper presents an investigation into the influence of resource allocation on the duration and cost of sub-tasks.Mathematical models are constructed for the relationships of the resource allocation quantity with the duration and cost of the sub-tasks.By considering the uncertainties,such as fluctuations in the sub-task duration and cost,rework iterations,and random overlaps,the tasks are simulated for various resource allocation schemes.The shortest duration and the minimum cost of the development task are first formulated as the objective function.Based on a multi-objective particle swarm optimization(MOPSO)algorithm,a multi-objective evolutionary algorithm is constructed to optimize the resource allocation scheme for the development task.Finally,an uninhabited aerial vehicle(UAV)is considered as an example of a development task to test the algorithm,and the optimization results of this method are compared with those based on non-dominated sorting genetic algorithm-II(NSGA-II),non-dominated sorting differential evolution(NSDE)and strength pareto evolutionary algorithm-II(SPEA-II).The proposed method is verified for its scientific approach and effectiveness.The case study shows that the optimization of the resource allocation can greatly aid in shortening the duration of the development task and reducing its cost effectively. 展开更多
关键词 resource allocation equipment development task multi-objective particle swarm optimization(MOPSO) develop ment task simulation.
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BeiDou Integrated Disaster Reduction Application Platform 被引量:3
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作者 Lü Xuefeng LIAO Yongfeng +1 位作者 LI Bo DENG Lan 《China Communications》 SCIE CSCD 2015年第8期169-182,共14页
To better improve the emergency communication and location-based services of disaster information reporting network for serious natural response and relieL disaster emergency the national natural disaster reduction ap... To better improve the emergency communication and location-based services of disaster information reporting network for serious natural response and relieL disaster emergency the national natural disaster reduction application platform based on BeiDou navigation satellite system is constructed. The administrative distributed platform is integrated with BeiDou positioning and multiple communication ways so as to achieve main disaster reduction application services, including disaster information acquisition and monitoring, emergency relief for trapped people, on-site emergency relief command service, relief supplies' transportation monitoring, and disaster information publishing service. By the platform, serious disaster information reporting time may be reduced to one hour and the emergency decision-making information service for serious natural disasters can be effectively improved, and it will be helpful to provide technical references for the industrial application and promotion of BeiDou inte- grated disaster reduction. 展开更多
关键词 beidou navigation satellite sys-tem disaster location service emergencycommunication disaster information manage- ment disaster emergency relief
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Energy consumption of electrooxidation systems with boron-doped diamond electrodes in the pulse current mode 被引量:2
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作者 Jun-jun Wei Xu-hui Gao +2 位作者 Li-fu Hei Jawaid Askari Cheng-ming Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2013年第1期106-112,共7页
A pulse current technique was conducted in a boron-doped diamond (BDD) anode system for electrochemical waste- water treatment. Due to the strong generation and weak absorption of hydroxyl radicals on the diamond su... A pulse current technique was conducted in a boron-doped diamond (BDD) anode system for electrochemical waste- water treatment. Due to the strong generation and weak absorption of hydroxyl radicals on the diamond surface, the BDD elec- trode possesses a powerful capability of electrochemical oxidation of organic compounds, especially in the pulse current mode. The influences of pulse current parameters such as current density, pulse duty cycle, and frequency were investigated in terms of chemical oxygen demand (COD) removal, average current efficiency, and specific energy consumption. The results demon- strated that the relatively high COD removal and low specific energy consumption were obtained simultaneously only if the current density or pulse duty cycle was adjusted to a reasonable value. Increasing the frequency slightly enhanced the COD re- moval and average current efficiency. A pulse-BDD anode system showed a stronger energy saving ability than a constant-BDD anode system when the electrochemical oxidation of phenol of the two systems was compared. The results prove that the pulse current technique is more cost-effective and more suitable for a BDD anode system for real wastewater treatment. A kinetic analysis was presented to explain the above results. 展开更多
关键词 diamond fihlls BORON doping electrochemical oxidation hydroxyl radicals energy consumption wastewater treat- ment
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MEASUREMENTAL RESEARCH ON THE MAGNETOMECHANICAL COUPLING PROPERTIES OF RARERARTH GIANT MAGNETOSTRICTION MATERIALS 被引量:2
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作者 C.Y. Li1) , H.Q. Yuan2) , F.X. Meng3) and Z. Zhou4) 1) Institute of Liaoning Technology,Jinzhou 121001 ,China 2) Northeastern University ,Shenyang 10006 ,China 3) Shenyang University ,Shenyang 110044 ,China 4) Xincheng Rare Earth Magnetostrictive Mate 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第4期357-360,共4页
The physical modelanditsequivalentcircuitoftestapparatusissetup by meansofimpedanceanalysis method. The magnetostriction coefficient, magnetomechanicalcoupling coefficient,frequency and anti- frequency of TbxDy1 - xFe... The physical modelanditsequivalentcircuitoftestapparatusissetup by meansofimpedanceanalysis method. The magnetostriction coefficient, magnetomechanicalcoupling coefficient,frequency and anti- frequency of TbxDy1 - xFe2 - z(0 27 ≤x ≤0 3 ,0 ≤z ≤0 1) rod are measured. Somecoupling problems with mechanicalstress and electromagnetic field such as flux leakage in magnetic path are discussed. The comparing calculated with tested resultsshowsthe accuracyof measurementand thesimplification of model. 展开更多
关键词 magnetostriction material magnetomechanicalcoupling properties experi ment
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THE INFLUENCE OF COMPOSITION AND TEMPERATURE OF BATH ANDAFTER-TREATMENT 0N COLORATION IN COLORING HOT DIPGALVANIZATION 被引量:3
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作者 Q. C. Le and J. Z. Cui School of Materials & Metallurgy , Northeastern University , Shenyang 110006 , China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第5期1217-1222,共6页
The 08 Al steel sheets were hot dip ped into Zn - Mn bath with 0 1 % Mn and 0 2 % Mn at600 ~420 ℃ bath tem perature , and then w ere treated in different w ays . The after - treat ments include cooling in t... The 08 Al steel sheets were hot dip ped into Zn - Mn bath with 0 1 % Mn and 0 2 % Mn at600 ~420 ℃ bath tem perature , and then w ere treated in different w ays . The after - treat ments include cooling in the air at room tem perature directly , holding at the upper part of thehot dip galvanizing furnace for 60 s an d then holding at 510 ±10 ℃for 90 s . The results in dicated that blue , yellow , and purple , w hose coloration varied with the co m position an d thetem perature of bath and the w ays of after - treat ment . Finally , the mechanism of coloredzinc coating w as discussed . 展开更多
关键词 coloring hot dip galvanization m anganese after - treat ment
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An ECT System Based on Improved RBF Network and Adaptive Wavelet Image Enhancement for Solid/Gas Two-phase Flow 被引量:3
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作者 陈夏 胡红利 +1 位作者 张娟 周屈兰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第2期359-367,共9页
Electrical capacitance tomography(ECT) is a non-invasive imaging technique that aims at visualizing the cross-sectional permittivity distribution and phase distribution of solid/gas two-phase flow based on the measure... Electrical capacitance tomography(ECT) is a non-invasive imaging technique that aims at visualizing the cross-sectional permittivity distribution and phase distribution of solid/gas two-phase flow based on the measured capacitance.To solve the nonlinear and ill-posed inverse problem:image reconstruction of ECT system,this paper proposed a new image reconstruction method based on improved radial basis function(RBF) neural network combined with adaptive wavelet image enhancement.Firstly,an improved RBF network was applied to establish the mapping model between the reconstruction image pixels and the capacitance values measured.Then,for better image quality,adaptive wavelet image enhancement technique was emphatically analyzed and studied,which belongs to a space-frequency analysis method and is suitable for image feature-enhanced.Through multi-level wavelet decomposition,edge points of the image produced from RBF network can be determined based on the neighborhood property of each sub-band;noise distribution in the space-frequency domain can be estimated based on statistical characteristics;after that a self-adaptive edge enhancement gain can be constructed.Finally,the image is reconstructed with adjusting wavelet coefficients.In this paper,a 12-electrode ECT system and a pneumatic conveying platform were built up to verify this image reconstruction algorithm.Experimental results demonstrated that adaptive wavelet image enhancement technique effectively implemented edge detection and image enhancement,and the improved RBF network and adaptive wavelet image enhancement hybrid algorithm greatly improved the quality of reconstructed image of solid/gas two-phase flow [pulverized coal(PC)/air]. 展开更多
关键词 electrical capacitance tomography.image reconstruction radial basis function network wavelet imageenhance ment
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