期刊文献+
共找到28篇文章
< 1 2 >
每页显示 20 50 100
Economos公司无模法密封制品生产技术简介
1
作者 李波 《橡胶工业》 CAS 北大核心 1996年第6期362-363,共2页
Economos公司无模法密封制品生产技术简介李波(山东枣庄橡胶厂27103)Econornos公司1988年研制成世界上首台由计算机控制的密封件车削加工机床,用于车削加工各种断面形状的环形密封件。1992年又研制成... Economos公司无模法密封制品生产技术简介李波(山东枣庄橡胶厂27103)Econornos公司1988年研制成世界上首台由计算机控制的密封件车削加工机床,用于车削加工各种断面形状的环形密封件。1992年又研制成高压射水技术,即以350MPa的高... 展开更多
关键词 密封制品 无模法 热塑性弹性体 制备
在线阅读 下载PDF
无模法生产文化石的研究
2
作者 闫振甲 何艳君 《福建建材》 2002年第1期26-27,共2页
人工合成文化石一直采用有模产生,投资大,折旧费高,速度馒。为克服现有技术的弱点,我们研究成功了无模生产文化石的新技术。这种新技术将生产投资降低95%,模具折旧降为零,生产速度快,制品精度高。本技术的研究成功,对推动文化石发展将... 人工合成文化石一直采用有模产生,投资大,折旧费高,速度馒。为克服现有技术的弱点,我们研究成功了无模生产文化石的新技术。这种新技术将生产投资降低95%,模具折旧降为零,生产速度快,制品精度高。本技术的研究成功,对推动文化石发展将起到积极的作用。 展开更多
关键词 无模法 文化石 装饰材料
在线阅读 下载PDF
无模拉丝法在Ti—Ni合金丝拉拔及锥形钢丝制造中的应用
3
作者 Kawag.,Y 肖敬兰 《湘钢译丛》 1992年第4期45-52,54,共9页
关键词 钢丝 钛镍合金 拉拔 无模拉丝
在线阅读 下载PDF
无模上铸法生产异形铝棒
4
作者 佐滕彰 邓福刊 《铝加工技术》 1992年第1期3-10,共8页
关键词 异形 铝棒 无模上铸 铸造
在线阅读 下载PDF
MARC在厚板回弹分析中的应用 被引量:3
5
作者 张亚岐 杨仁康 +1 位作者 成振坤 周副权 《锻压技术》 CAS CSCD 北大核心 2016年第11期38-42,共5页
由于高强板的应用使厚板回弹更加难以精确控制,而传统冲压分析软件的壳单元对厚板回弹基本失效,为此,利用具有强大非线性分析功能的MARC软件对厚板回弹进行分析。通过分析厚板相对于薄板的成形性特点,归纳出厚板回弹分析的控制要点,并... 由于高强板的应用使厚板回弹更加难以精确控制,而传统冲压分析软件的壳单元对厚板回弹基本失效,为此,利用具有强大非线性分析功能的MARC软件对厚板回弹进行分析。通过分析厚板相对于薄板的成形性特点,归纳出厚板回弹分析的控制要点,并依据相应的控制要点梳理出MARC回弹分析的一般流程。为最大限度降低有模法人为拉应力的形成以及计算成本,提出有模法与无模法相结合的混模回弹分析方法。最后以某车架纵梁为例,对该算法进行验证,结果表明所提及的算法在减少计算成本的同时有效降低人为拉应力的产生,且实体单元的回弹更加逼近实测值。 展开更多
关键词 厚板 回弹 MARC 无模法
原文传递
Numerical analysis of coupled finite element with element-free Galerkin in sheet flexible-die forming 被引量:7
6
作者 王忠金 袁斌先 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期462-469,共8页
A numerical method for coupled deformation between sheet metal and flexible-die was proposed. Based on the updated Lagrangian (UL) formulation, the elastoplastic deformation of sheet metal was analyzed with finite e... A numerical method for coupled deformation between sheet metal and flexible-die was proposed. Based on the updated Lagrangian (UL) formulation, the elastoplastic deformation of sheet metal was analyzed with finite element method (FEM) and the bulk deformation of flexible-die was analyzed with element-free Galerkin method (EFGM). The frictional contact between sheet metal and flexible-die was treated by the penalty function method. The sheet elastic flexible-die bulging process was analyzed with the FEM-EFGM program for coupled deformation between sheet metal and bulk flexible-die, called CDSB-FEM-EFGM for short. Compared with finite element code DEFORM-2D and experiment results, the CDSB-FEM-EFGM program is feasible. This method provides a suitable numerical method to analyze sheet flexible-die forming. 展开更多
关键词 sheet flexible-die forming finite element method element-free Galerkin method coupling aluminum alloy
在线阅读 下载PDF
Combined method for fast 3-D finite element modeling of nondestructive testing signal 被引量:1
7
作者 林鹤云 《Journal of Southeast University(English Edition)》 EI CAS 2004年第2期195-199,共5页
A combined method for the fast 3-D finite element modeling of defect responses in nondestructive testing of electromagnetics is presented. The method consists of three numerical techniques: zoom-in technique, differen... A combined method for the fast 3-D finite element modeling of defect responses in nondestructive testing of electromagnetics is presented. The method consists of three numerical techniques: zoom-in technique, difference field technique and iterative solution technique. Utilizing the zoom-in technique, the computational zone focuses on a relatively small domain around the defect. Employing the difference field technique, the axisymmetrical field solution corresponding to the case with no defect can be used to simplify the mesh generation and obtain the modeling results quickly. Using the iterative solution technique, the matrix equation system in the 3-D finite element modeling of nondestructive probe signals can easily be solved. The sample calculation shows that the presented method is highly effective and can consequently save significant computer resources. 展开更多
关键词 Electromagnetic fields Finite element method Iterative methods Probes
在线阅读 下载PDF
Template-free hydrothermal synthesis and gas-sensitivity of hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres 被引量:2
8
作者 TIAN Li LIU Qiang +1 位作者 WU Jie-ling YI Yi-tao 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第7期1946-1954,共9页
Hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres have been synthesized by a simple one-pot template-free hydrothermal method with copper sulfate,cobalt acetate and ammonia as raw materials.The products were charac... Hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres have been synthesized by a simple one-pot template-free hydrothermal method with copper sulfate,cobalt acetate and ammonia as raw materials.The products were characterized by powder X-ray diffraction,energy dispersive X-ray analysis,selected area electron diffraction,high-resolution transmission electron microscopy,scanning electron microscopy and BET measurements.The research results show that the hollow Cu_(0.3)Co_(2.7)O_(4) microspheres consist of single-crystalline nanocubes with the diameter of about 20 nm.The formation mechanism of hollow Cu_(0.3)Co_(2.7)O_(4) microspheres is suggested as Ostwald ripening in a solid-solution-solid process,and Cu_(0.3)Co_(2.7)O_(4) microspheres are mesoporous containing two pore sizes of 3.3 and 5.9 nm.The as-prepared Cu_(0.3)Co_(2.7)O_(4) sensors have optimal gas responses to 50×10^(−6) mg/m^(3) C_(2)H_(5)OH at 190℃. 展开更多
关键词 Cu_(0.3)Co_(2.7)O_(4)oxides MICROSPHERE inorganic compounds nanostructures template-free hydrothermal method
在线阅读 下载PDF
Radio-map Establishment based on Fuzzy Clustering for WLAN Hybrid KNN/ANN Indoor Positioning 被引量:9
9
作者 Zhou Mu Xu Yubin Ma Lin 《China Communications》 SCIE CSCD 2010年第3期64-80,共17页
A novel radio-map establishment based on fuzzy clustering for hybrid K-Nearest Neighbor (KNN) and Artifi cial Neural Network (ANN) position algorithm in WLAN indoor environment is proposed. First of all, the Principal... A novel radio-map establishment based on fuzzy clustering for hybrid K-Nearest Neighbor (KNN) and Artifi cial Neural Network (ANN) position algorithm in WLAN indoor environment is proposed. First of all, the Principal Component Analysis (PCA) is utilized for the purpose of simplifying input dimensions of position estimation algorithm and saving storage cost for the establishment of radio-map. Then, reference points (RPs) calibrated in the off-line phase are divided into separate clusters by Fuzzy C-means clustering (FCM), and membership degrees (MDs) for different clusters are also allocated to each RPs. However, the singular RPs cased by the multi-path effect signifi cantly decreases the clustering performance. Therefore, a novel radio-map establishment method is presented based on the modifi cation of signal samples recorded at singular RPs by surface fitting. In the on-line phase, the region which the mobile terminal (MT) belongs to is estimated according to the MDs firstly. Then, in estimated small dimensional regions, MT's coordinates are calculated byKNN positioning method for efficiency purpose. However, for the regions including singular RPs, ANN method is utilized because ofits great pattern matching ability. Furthermore, compared with other typical indoor positioning methods, feasibility and effectiveness of this hybrid KNN/ANN method are also verified by the experimental results in static and tracking situations. 展开更多
关键词 WLAN indoor location fuzzy clustering principal component artificial neural network radio-map
在线阅读 下载PDF
A DERIVATIVE-FREE ALGORITHM FOR UNCONSTRAINED OPTIMIZATION 被引量:1
10
作者 Peng Yehui Liu Zhenhai 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2005年第4期491-498,共8页
In this paper a hybrid algorithm which combines the pattern search method and the genetic algorithm for unconstrained optimization is presented. The algorithm is a deterministic pattern search algorithm,but in the sea... In this paper a hybrid algorithm which combines the pattern search method and the genetic algorithm for unconstrained optimization is presented. The algorithm is a deterministic pattern search algorithm,but in the search step of pattern search algorithm,the trial points are produced by a way like the genetic algorithm. At each iterate, by reduplication,crossover and mutation, a finite set of points can be used. In theory,the algorithm is globally convergent. The most stir is the numerical results showing that it can find the global minimizer for some problems ,which other pattern search algorithms don't bear. 展开更多
关键词 unconstrained optimization pattern search method genetic algorithm global minimizer.
在线阅读 下载PDF
Numerical Simulation of Independent Advance of Ore Breaking in the Non-pillar Sublevel Caving Method 被引量:22
11
作者 ZHOU Chuan-bo YAO Ying-kang +3 位作者 GUO Liao-wu YIN Xiao-peng FAN Xiao-feng SHANG Ying 《Journal of China University of Mining and Technology》 EI 2007年第2期295-300,共6页
The mechanism of stress generation and propagation by detonation loading in five separate independent advance of ore breaking patterns is discussed in the paper. An elastic numerical model was developed using AN- SYS/... The mechanism of stress generation and propagation by detonation loading in five separate independent advance of ore breaking patterns is discussed in the paper. An elastic numerical model was developed using AN- SYS/LS-DYNA 3D Nonlinear Dynamic Finite Element Software. In this package ANSYS is the preprocessor and LS-DYNA is the postprocessor. Numerical models in the paper to actual were l:10 and the element mesh was dissected in scanning mode utilizing the symmetry characteristics of the numerical model. Five different advance rates were studied. Parameters, such as the time required to maximum stress, the action time of the available stress, the maximum velocity of the nodes, the stress penetration time, the magnitude of the stress peak and the time duration for high stress were numerically simulated. The 2.2 m advance appeared optimum from an analysis of the simulation results. The results from numerical simulation have been validated by tests with physical models. 展开更多
关键词 non-pillar sublevel caving method independent advance of ore breaking numerical simulation model test
在线阅读 下载PDF
Deriving Vibration Modes of Semi-infinite Chain Model by “Invariant Eigen-operator”Method
12
作者 FAN Hong-Yi WU Hao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第1期50-52,共3页
For the first time, we introduce a fully quantum mechanical Hamiltonian for a semi-infinite chain model of atoms. We then derive the vibration modes of this model by virtue of the "invariant eigen-operator" method i... For the first time, we introduce a fully quantum mechanical Hamiltonian for a semi-infinite chain model of atoms. We then derive the vibration modes of this model by virtue of the "invariant eigen-operator" method in two different cases, which is concise and revealing. 展开更多
关键词 semi-infinite chain vibration modes IEO method
在线阅读 下载PDF
Collision avoidance planning in multi-robot system based on improved artificial potential field and rules 被引量:4
13
作者 原新 朱齐丹 严勇杰 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第3期413-418,共6页
For real-time and distributed features of multi-robot system,the strategy of combining the improved artificial potential field method and the rules based on priority is proposed to study the collision avoidance planni... For real-time and distributed features of multi-robot system,the strategy of combining the improved artificial potential field method and the rules based on priority is proposed to study the collision avoidance planning in multi-robot systems. The improved artificial potential field based on simulated annealing algorithm satisfactorily overcomes the drawbacks of traditional artificial potential field method,so that robots can find a local collision-free path in the complex environment. According to the movement vector trail of robots,collisions between robots can be detected,thereby the collision avoidance rules can be obtained. Coordination between robots by the priority based rules improves the real-time property of multi-robot system. The combination of these two methods can help a robot to find a collision-free path from a starting point to the goal quickly in an environment with many obstacles. The feasibility of the proposed method is validated in the VC-based simulated environment. 展开更多
关键词 artificial potential field simulated annealing avoiding rules collision avoidance planning multirobots
在线阅读 下载PDF
New Compacton Solutions and Solitary Pattern Solutions for Modified Nonlinearly Dispersive mK(m,n,a,b) Equation
14
作者 YU Ya-Xuan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第10期637-640,共4页
In this paper exact solutions of a new modified nonlinearly dispersive equation (simply called inK(m, n, a, b) Ua Ub equation), u^m-1 ut + α( u^n)x +β(u^a(u^b)xx)x = 0, is investigated by using some dir... In this paper exact solutions of a new modified nonlinearly dispersive equation (simply called inK(m, n, a, b) Ua Ub equation), u^m-1 ut + α( u^n)x +β(u^a(u^b)xx)x = 0, is investigated by using some direct algorithms. As a result, abundant new compacton solutions (solitons with the absence of infinite wings) and solitary pattern solutions (having infinite slopes or cusps) are obtained. 展开更多
关键词 mK(m n a b) equation compacton solution solitary pattern solution
在线阅读 下载PDF
The study of perfectly matched layer absorbing boundaries for SH wave fields 被引量:5
15
作者 Liu Jiong Ma Jian-wei Yang Hui-zhu 《Applied Geophysics》 SCIE CSCD 2009年第3期267-274,300,301,共10页
When modeling wave propagation in infinite space, it is necessary to have stable absorbing boundaries to effectively eliminate spurious reflections from the truncation boundaries. The SH wave equations for Perfectly M... When modeling wave propagation in infinite space, it is necessary to have stable absorbing boundaries to effectively eliminate spurious reflections from the truncation boundaries. The SH wave equations for Perfectly Matched Layers (PML) are deduced and their Crank-Nicolson scheme are presented in this paper. We use the second-, sixth-, and tenth-order finite difference and pseudo-spectral algorithms to compute the spatial derivatives. Two numerical models, a homogeneous isotropic medium and a multi-layer model with a cave, are designed to investigate how the absorbing boundary width and the algorithms determine PML effects. Numerical results show that, for PML, the low-order finite difference algorithms have fairly good absorbing effects when the absorbing boundary is thin, whereas, high-order algorithms always have good absorption when the boundary is thick. Finally, we discuss the reflection coefficient and point out its shortcomings, which is why we use the SNR to quantitatively scale the PML effects, 展开更多
关键词 absorbing boundary PML SH wave fields
在线阅读 下载PDF
An element-free Galerkin method for ground penetrating radar numerical simulation 被引量:2
16
作者 冯德山 郭荣文 王洪华 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期261-269,共9页
An element-free Galerkin method(EFGM) is used to solve the two-dimensional(2D) ground penetrating radar(GPR)modelling problems, due to its simple pre-processing, the absence of elements and high accuracy. Different fr... An element-free Galerkin method(EFGM) is used to solve the two-dimensional(2D) ground penetrating radar(GPR)modelling problems, due to its simple pre-processing, the absence of elements and high accuracy. Different from element-based numerical methods, this approach makes nodes free from the elemental restraint and avoids the explicit mesh discretization. First, we derived the boundary value problem for the 2D GPR simulation problems. Second, a penalty function approach and a boundary condition truncated method were used to enforce the essential and the absorbing boundary conditions, respectively. A three-layered GPR model was used to verify our element-free approach. The numerical solutions show that our solutions have an excellent agreement with solutions of a finite element method(FEM). Then, we used the EFGM to simulate one more complex model to show its capability and limitations. Simulation results show that one obvious advantage of EFGM is the absence of element mesh, which makes the method very flexible. Due to the use of MLS fitting, a key feature of EFM, is that both the dependent variable and its gradient are continuous and have high precision. 展开更多
关键词 element-free Galerkin method moving least-squares method ground penetrating radar forward simulation
在线阅读 下载PDF
Phase Diagram of XY Model with Nematic Coupling on the Simple Cubic Lattice
17
作者 吕建平 陈庆虎 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第1期166-168,共3页
Using cluster Monte Carlo method, we numerically investigate the coupling on the simple cubic lattice. We determine critical lines belong to the criticality in the XY model with nematic three-dimensional XY universali... Using cluster Monte Carlo method, we numerically investigate the coupling on the simple cubic lattice. We determine critical lines belong to the criticality in the XY model with nematic three-dimensional XY universality class in variable of θ (2θ) between the XY-ferromagnetic (nematic) and disordered states. Fhrthermore, the phase transition between the XY-ferromagnetic and the nematie states is found to be in the three-dimensional Ising universality class. The critical points are determined from the intersections of Binder ratios for various system sizes. With two sets of critical points obtained, we finally construct the phase diagram on the A-J plane. 展开更多
关键词 nematic phase phase diagram scaling analysis
在线阅读 下载PDF
Ranging Error Correction Based on a Prior Error Model
18
作者 Xiaofei Wang Hongkun He +1 位作者 Yan Xu Yang Lei 《China Communications》 SCIE CSCD 2018年第3期91-99,共9页
Wireless technology provides accurate positioning in indoor environments using time of arrival(TOA) based ranging techniques. However, the positioning accuracy is degraded due to the ranging errors caused by multipath... Wireless technology provides accurate positioning in indoor environments using time of arrival(TOA) based ranging techniques. However, the positioning accuracy is degraded due to the ranging errors caused by multipath and non-line-of-sight(NLOS) propagation. In this paper, a ranging error correction method is proposed to improve positioning performance. A TOA ranging error model(TREM) is built to provide the prior information for ranging error correction first. The mean value of TREM within a certain interval is used as the ranging error correction value(RECV). As the RECV may be unreasonable sometimes, we adjust it according to the actual positioning situation and then exploit the final RECV to correct ranging data. The experimental results show that the proposed method could well reduce ranging errors and the positioning performance is obviously improved when using corrected ranging data. 展开更多
关键词 time of arrival (TOA) TOA rang-ing error model (TREM) ranging error cor-rection value (RECV) the adjustment of theRECV
在线阅读 下载PDF
Numerical simulation of land subsidence and verification of its character for an iron mine using sublevel caving 被引量:12
19
作者 Cao Shuai Song Weidong +2 位作者 Deng Dan Lei Yuankun Lan Jianqiang 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第2期327-332,共6页
Combined with a digital bored photography system and in-situ statistics concerning the joints and fissures of both ore-body and surrounding rock,a 2D discrete model was constructed using UDEC.The stress field and disp... Combined with a digital bored photography system and in-situ statistics concerning the joints and fissures of both ore-body and surrounding rock,a 2D discrete model was constructed using UDEC.The stress field and displacement field changes of different sublevel stoping systems were also studied.Changes in the overlying rock strata settlement pattern has been analyzed and validated by in-situ monitoring data.The results show that:in the caving process,there exists an obvious delay and jump for the overlying rock strata displacement over time,and a stable arch can be formed in the process of caving,which leads to hidden goafs.Disturbed by the mining activity,a stress increase occurred in both the hanging wall and the foot wall,demonstrating a hump-shaped distribution pattern.From the comparison between simulation results and in-situ monitoring results,land subsidence shows a slow-development,suddenfailure,slow-development cycle pattern,which leads eventually to a stable state.This pattern validates the existence of balanced arch and hidden goafs. 展开更多
关键词 Block caving Joint survey UDEC model Ground settlement Balanced arch Hidden goafs
在线阅读 下载PDF
Influence of Blurred Ways on Pattern Recognition of a Scale-Free Hopfield Neural Network
20
作者 常文利 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第1期195-199,共5页
We investigate the influence of blurred ways on pattern recognition of a Barabasi-Albert scale-free Hopfield neural network (SFHN) with a small amount of errors. Pattern recognition is an important function of infor... We investigate the influence of blurred ways on pattern recognition of a Barabasi-Albert scale-free Hopfield neural network (SFHN) with a small amount of errors. Pattern recognition is an important function of information processing in brain. Due to heterogeneous degree of scale-free network, different blurred ways have different influences on pattern recognition with same errors. Simulation shows that among partial recognition, the larger loading ratio (the number of patterns to average degree P/ (k) ) is, the smaller the overlap of SFHN is. The influence of directed (large) way is largest and the directed (small) way is smallest while random way is intermediate between them. Under the ratio of the numbers of stored patterns to the size of the network PIN is less than O. 1 conditions, there are three families curves of the overlap corresponding to directed (small), random and directed (large) blurred ways of patterns and these curves are not associated with the size of network and the number of patterns. This phenomenon only occurs in the SFHN. These conclusions are benefit for understanding the relation between neural network structure and brain function. 展开更多
关键词 scale-free neural network pattern recognition blurred ways
在线阅读 下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部