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组装中低速磁浮缓和曲线轨排线型理论及应用
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作者 储华 《安装》 2016年第6期31-33,共3页
本文介绍了中低速磁浮缓和曲线轨排的结构形式,曲线公式计算,组装技术和组装方法的理论分析。并针对组装过程中的问题和难点进行描述和解决。
关键词 中低速磁浮 缓和曲线轨排 结构形式 组装线型理论分析
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纤维缠绕机出现线型误差的原因分析 被引量:3
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作者 韩晓军 《武汉理工大学学报》 EI CAS CSCD 2001年第10期63-66,共4页
纤维缠绕机由于诸方面的原因 ,包括机械系统设计制造的原因、控制系统的原因、工艺参数的选定及运行操作方面的原因等 ,实际的排线精度与所设计线型之间难免存在一定的误差。
关键词 纤维缠绕机 排线精度 线型误差 原因分析 理论线型 缠绕线型
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舌簧阀升程限制器线型设计方法 被引量:2
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作者 丁兴宇 米小珍 王枫 《化工机械》 CAS 2016年第2期178-182,共5页
为了对升程限制器的线型设计方法进行系统分析,对比了悬臂梁法、振动力学法和有限元法3种理论线型设计方法。为了保证理论线型的精度,同时又便于实际加工,对比分析了直线型和单曲率直线型升程限制器理论线型拟合方法。实验结果表明:单... 为了对升程限制器的线型设计方法进行系统分析,对比了悬臂梁法、振动力学法和有限元法3种理论线型设计方法。为了保证理论线型的精度,同时又便于实际加工,对比分析了直线型和单曲率直线型升程限制器理论线型拟合方法。实验结果表明:单曲率直线拟合的有限元法升程限制器理论线型既能保证理论线型的精度,又能有效减小应力集中,提高阀片使用寿命。 展开更多
关键词 舌簧阀 升程限制器 理论线型设计 线型拟合
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HVAC系统多变量热力过程的自适应控制研究及应用 被引量:1
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作者 刘贤坤 《制冷与空调(四川)》 2003年第3期11-14,共4页
本文在热动力学分析的基础上,利用自适应控制和线型系统理论,设计出一种适用于多控制区域、多输入/输出、多扰动HVAC系统的自适应控制器。仿真结果显示出:这种了控制器的反应速度和稳定性大大高于固定增益控制器。
关键词 自适应控制 线型系统理论 自适应控制器 反应速度 稳定性 HVAC系统
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ON THE DESIGN OF A NEW HUMAN COMFORT INDEX 被引量:2
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作者 冯业荣 王安宇 林镇国 《Journal of Tropical Meteorology》 SCIE 2004年第1期106-112,共7页
In designing the human comfort index (CI) used in Guangzhou, a Gaussian curve was adopted as the fundamental profile to develop a traw hat?model of comfort index. The model projects low or high temperatures into low i... In designing the human comfort index (CI) used in Guangzhou, a Gaussian curve was adopted as the fundamental profile to develop a traw hat?model of comfort index. The model projects low or high temperatures into low index values and the moderate temperatures into high index values. Air temperature was chosen as a basic factor in the model. Other factors such as humidity, sunshine and wind speed were introduced by considering them as temperature departures to an equivalent apparent temperature (EAT). Since the index is a relative index, 25C was chosen as an ideal apparent temperature (the most comfortable state) and a maximum CI value of 100 was assigned at this temperature. While in other circumstances, the index would be lower than 100. By utilizing this model, the daily comfort index values had been calculated for Guangzhou city for 1998-1999, using mean temperature, mean humidity, mean wind speed and total hours of sunshine. Results show that the new model was reasonable and practicable. Not only could it reflect the monthly variation of human comfort in Guangzhou, but also was sensitive to short-term changes of weather conditions. 展开更多
关键词 equivalent apparent temperature (EAT) human comfort index (CI) Gaussian function
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Initial pre-stress finding procedure and structural performance research for Levy cable dome based on linear adjustment theory 被引量:4
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作者 ZHANG Li-mei CHEN Wu-jun DONG Shi-lin 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第9期1366-1372,共7页
The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented here... The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented herein for the initial pre-stress finding procedure of complete cable-strut assembly. This method is based on the linear adjustment theory and does not take into account the material behavior. By using this method,the initial pre-stress of the multi self-stress modes can be found easily and the cal-culation process is simplified and efficient also. Finally,the initial pre-stress and structural performances of a particular Levy cable dome are analyzed comprehensively. The algorithm has proven to be efficient and correct,and the numerical results are valuable for practical design of Levy cable dome. 展开更多
关键词 Linear adjustment theory Cable-strut structure Initial pre-stress Levy cable dome Structural performances analysis
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Modeling and control for hydraulic transmission of unmanned ground vehicle 被引量:1
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作者 王岩 张泽 秦绪情 《Journal of Central South University》 SCIE EI CAS 2014年第1期124-129,共6页
Variable pump driving variable motor(VPDVM) is the future development trend of the hydraulic transmission of an unmanned ground vehicle(UGV).VPDVM is a dual-input single-output nonlinear system with coupling,which is ... Variable pump driving variable motor(VPDVM) is the future development trend of the hydraulic transmission of an unmanned ground vehicle(UGV).VPDVM is a dual-input single-output nonlinear system with coupling,which is difficult to control.High pressure automatic variables bang-bang(HABB) was proposed to achieve the desired motor speed.First,the VPDVM nonlinear mathematic model was introduced,then linearized by feedback linearization theory,and the zero-dynamic stability was proved.The HABB control algorithm was proposed for VPDVM,in which the variable motor was controlled by high pressure automatic variables(HA) and the variable pump was controlled by bang-bang.Finally,simulation of VPDVM controlled by HABB was developed.Simulation results demonstrate the HABB can implement the desired motor speed rapidly and has strong robustness against the variations of desired motor speed,load and pump speed. 展开更多
关键词 unmanned ground vehicle HYDRAULIC nonlinear system high pressure automatic variables bang-bang
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Risk assessment model of tunnel water inrush based on improved attribute mathematical theory 被引量:9
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作者 YANG Xiao-li ZHANG Sheng 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第2期379-391,共13页
Tunnel water inrush is one of the common geological disasters in the underground engineering construction.In order to effectively evaluate and control the occurrence of water inrush,the risk assessment model of tunnel... Tunnel water inrush is one of the common geological disasters in the underground engineering construction.In order to effectively evaluate and control the occurrence of water inrush,the risk assessment model of tunnel water inrush was proposed based on improved attribute mathematical theory.The trigonometric functions were adopted to optimize the attribute mathematical theory,avoiding the influence of mutation points and linear variation zones in traditional linear measurement functions on the accuracy of the model.Based on comprehensive analysis of various factors,five parameters were selected as the evaluation indicators for the model,including tunnel head pressure,permeability coefficient of surrounding rock,crushing degree of surrounding rock,relative angle of joint plane and tunnel section size,under the principle of dimension rationality,independence,directness and quantification.The indicator classifications were determined.The links among measured data were analyzed in detail,and the objective weight of each indicator was determined by using similar weight method.Thereby the tunnel water inrush risk assessment model is established and applied in four target segments of two different tunnels in engineering.The evaluation results and the actual excavation data agree well,which indicates that the model is of high credibility and feasibility. 展开更多
关键词 tunnel water inrush risk assessment model attribute mathematical theory nonlinear measurement function similar weight method
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A novel finite element model for single-layered wire strand 被引量:2
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作者 周伟 田红旗 《Journal of Central South University》 SCIE EI CAS 2013年第6期1767-1771,共5页
A new finite element model for single-layered strand was investigated for accurate and efficient mechanical behavior analysis.Mathematical model was created by sectional path-nodes sweeping and dynamic node-beam mappi... A new finite element model for single-layered strand was investigated for accurate and efficient mechanical behavior analysis.Mathematical model was created by sectional path-nodes sweeping and dynamic node-beam mapping.Geometric relations between nodes in center core wire and helical wires were deduced in tension and bending incorporating material elasticity theory and deformation geometrical compatibility.Based on Timoshenko beam theory,strand of a pitch length was modeled with specific material,geometric parameters and synthesized constraint equations defined in ANSYS software,and predetermined load cases were performed.The obtained results show that discrepancies between suggested method and Costello theory do not exceed 1.51% in tension and 6.21% in bending,which verifies the correctness and accuracy of the suggested finite element model in predicting mechanical behavior of single-layered wire strand. 展开更多
关键词 wire strand finite element analysis nodal constraint equation geometrical compatibility Timoshenko beam theory
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Numerical analysis on coal-breaking process under high pressure water jet 被引量:7
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作者 CHEN Jin-hua LIANG Yun-pei CHENG Guo-qiang 《Journal of Coal Science & Engineering(China)》 2009年第3期289-294,共6页
Based on the theory of nonlinear dynamic finite element,the control equation ofcoal and water jet was acquired in the coal breaking process under a water jet.The calculationmodel of coal breaking under a water jet was... Based on the theory of nonlinear dynamic finite element,the control equation ofcoal and water jet was acquired in the coal breaking process under a water jet.The calculationmodel of coal breaking under a water jet was established;the fluid-structure couplingof water jet and coal was implemented by penalty function and convection calculation.The dynamic process of coal breaking under a water jet was simulated and analyzed bycombining the united fracture criteria of the maximum tensile strain and the maximal shearstrain in the two cases of damage to coal and damage failure to coal. 展开更多
关键词 numerical analysis coal breaking high pressure water jet fluid-structure coupling DAMAGE DRILL
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Research on Stream Cipher Model Based on Chaos Theory
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作者 Sun Wenjie 《International Journal of Technology Management》 2013年第2期91-93,共3页
Chaos is a similar and random process which is very sensitive to initial value in deterministic system. It is a performance of nonlinear dynamical system with built-in randomness. Combined with the advantages and disa... Chaos is a similar and random process which is very sensitive to initial value in deterministic system. It is a performance of nonlinear dynamical system with built-in randomness. Combined with the advantages and disadvantages of the present chaos encryption model, the paper proposes a chaotic stream cipher model based on chaos theory, which not only overcomes finite precision effect, but also improves the randomness of chaotic system and output sequence. The Sequence cycle theory generated by the algorithm can reach more than 10600 at least, which completely satisfies the actual application requirements of stream cipher system. 展开更多
关键词 chaos theory stream cipher ALGORITHM
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Research on Compress or Modeling Methods
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作者 Zhao Xincun Wang Lei Zhang Hailun Li Zhen Wang Shanshan 《Review of Global Academics》 2014年第5期389-392,共4页
This article describes some of the common modeling method on compressor: black-box model, theoretical model, hybrid model and so on. It compares them, pointing out its advantages and disadvantages. In order to improv... This article describes some of the common modeling method on compressor: black-box model, theoretical model, hybrid model and so on. It compares them, pointing out its advantages and disadvantages. In order to improve the design of the compressor and its performance, this paper proposes a new modeling theory. In this model, when you make the curve fitting between multiple variables, variables can be divided into many groups. Firstly, looking for the relationship between the variables in groups, and then you can find the relationship between aggregated group. 展开更多
关键词 co mpressor MODELING OPTIMIZATION CONTROL mathematical modeling promotion
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微积分的再思考 被引量:5
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作者 米哈伊·列夫舍茨 《数学的实践与认识》 CSCD 北大核心 2009年第11期211-216,共6页
基于代数和显式一致估计的微积分思想可以追溯到前牛顿时代,或者欧拉和拉格朗日.由于所涉及的数学非常简单,新的方法可以从一些简单的例子出发,直接、自然却严格地建立微分和积分的流线型理论,并不需要连续性、极限和紧性的概念.
关键词 微积分 简化 代数 线型理论
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The Complexity and Application Research of Several Attractors About Economic System Time Series 被引量:1
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作者 Tao Sun Junhai Ma 《Journal of Systems Science and Information》 2006年第3期571-579,共9页
In this paper, time series with stable convergence, saddles, Hopf bifurcations and chaotic points in one kind of complicated systems have been studied in respects of: fractal characteristic and fractal dimension. By ... In this paper, time series with stable convergence, saddles, Hopf bifurcations and chaotic points in one kind of complicated systems have been studied in respects of: fractal characteristic and fractal dimension. By using phase space reconstruction technology of chaotic time series, work of reconstruction has been done respectively on these four different conditions and further by applying wavelet network models, work of modeling and prediction have been done accordingly. The results indicate: treatment of zero mean value in the identification of the chaotic models has no obvious influence on precision and length of predictions, while the treatment by Fourier Filter can damage effectiveness of prediction. 展开更多
关键词 stable convergence SADDLE BIFURCATION FRACTAL chaos models of non-linear technology of reconstruction
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ASYMPTOTICS OF MEAN TRANSFORMATION ESTIMATORS WITH ERRORS IN VARIABLES MODEL 被引量:1
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作者 CUI Hengjian 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2005年第4期446-455,共10页
This paper addresses estimation and its asymptotics of mean transformation θ = E[h(X)] of a random variable X based on n lid. observations from errors-in-variables model Y = X+ v, where v is a measurement error wi... This paper addresses estimation and its asymptotics of mean transformation θ = E[h(X)] of a random variable X based on n lid. observations from errors-in-variables model Y = X+ v, where v is a measurement error with a known distribution and h(.) is a known smooth function. The asymptotics of deconvolution kernel estimator for ordinary smooth error distribution and expectation extrapolation estimator are given for normal error distribution respectively. Under some mild regularity conditions, the consistency and asymptotically normality are obtained for both type of estimators. Simulations show they have good performance. 展开更多
关键词 Deconvolution kernel estimator ERRORS-IN-VARIABLES CONSISTENCY asymptotic normality.
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THE PERIODIC VOLTERRA MODEL WITH MUTUAL INTERFERENCE AND IMPULSIVE EFFECT 被引量:2
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作者 YUJUAN ZHANG LANSUN CHEN 《International Journal of Biomathematics》 2012年第3期77-91,共15页
In this paper, a periodic Volterra model with mutual interference and impulsive effect is proposed and analyzed. By applying the Floquet theory of impulsive differential equa- tion, some conditions are obtained for th... In this paper, a periodic Volterra model with mutual interference and impulsive effect is proposed and analyzed. By applying the Floquet theory of impulsive differential equa- tion, some conditions are obtained for the linear stability of semi-trivial periodic solution. Some sufficient conditions are also given for the permanence of the system. Further, stan- dard bifurcation theory is used to show the existence of coexistence state which arises near the semi-trivial periodic solution. Finally, theoretical results are confirmed by some special cases of the system. 展开更多
关键词 Mutual interference impulsive effect EXTINCTION BIFURCATION permanence.
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Existence results for degenerate p(x)-Laplace equations with Leray-Lions type operators 被引量:1
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作者 HO Ky SIM Inbo 《Science China Mathematics》 SCIE CSCD 2017年第1期133-146,共14页
We show the existence and multiplicity of solutions to degenerate p(x)-Laplace equations with Leray-Lions type operators using direct methods and critical point theories in Calculus of Variations and prove the uniquen... We show the existence and multiplicity of solutions to degenerate p(x)-Laplace equations with Leray-Lions type operators using direct methods and critical point theories in Calculus of Variations and prove the uniqueness and nonnegativeness of solutions when the principal operator is monotone and the nonlinearity is nonincreasing. Our operator is of the most general form containing all previous ones and we also weaken assumptions on the operator and the nonlinearity to get the above results. Moreover, we do not impose the restricted condition on p(x) and the uniform monotonicity of the operator to show the existence of three distinct solutions. 展开更多
关键词 p(x)-Laplacian weighted variable exponent Lebesgue-Sobolev spaces multiplicity a priori bound Leray-Lions type operators
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The instability of an elastic planet with a liquid core
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作者 Shengjun Fan Yanju Liu Fei Jia 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2022年第12期101-110,共10页
Considering a spherical planet with a liquid core surrounded by a solid shell,we developed a quasi-static model to investigate the deformation of the double-layered planet with self-gravity and obtained the boundary v... Considering a spherical planet with a liquid core surrounded by a solid shell,we developed a quasi-static model to investigate the deformation of the double-layered planet with self-gravity and obtained the boundary value problem about radial equilibrium,which is solved by the numerical methods.The effects of governing parameters about geometry,density and bulk modulus on the deformation of the planet with self-gravity were discussed.In addition,we also developed the incremental equation theory to investigate the stability of the double-layered planet under its own gravity.It is concluded that instability is more likely to occur on the planet with smaller liquid cores when the outer radius and density of the planets are constant.Although we only study special double-layered planets,these methods can be conveniently extended to complex multi-layered planets. 展开更多
关键词 INSTABILITY Double-layered PLANET GRAVITY DEFORMATION
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A PERTURBED SOLUTION OF SEA-AIR OSCILLATOR FOR THE ENSO MECHANISM
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作者 MOJiaqi LINWantao WANGHui 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2005年第2期219-223,共5页
A class of coupled system of the El Nino/La Nino-Southern Oscillation (ENSO)mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSOmodel are obtained and the asymptotic beh... A class of coupled system of the El Nino/La Nino-Southern Oscillation (ENSO)mechanism is studied. Using the perturbed theory, the asymptotic expansions of the solution for ENSOmodel are obtained and the asymptotic behavior of the solution for corresponding problem isconsidered. And it is pointed out that the solution tends to the corresponding attractor as t → ∞. 展开更多
关键词 NONLINEAR perturbation theory El Nino/La Nino-Southern Oscillation model
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Optical Conductivity of Graphene Sheet Including Electron-Phonon Interaction
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作者 Hamze Mousavi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第3期482-484,共3页
Using an expression of optical conductivity,based on the linear response theory,the Green's function technique and within the Holstein Hamiltonian model,the effect of electron-phonon interaction on the optical con... Using an expression of optical conductivity,based on the linear response theory,the Green's function technique and within the Holstein Hamiltonian model,the effect of electron-phonon interaction on the optical conductivity of graphene plane is studied.It is found that the electron-phonon coupling increases the optical conductivity of graphene sheet in the low frequency region due to decreasing quasiparticle weight of electron excitation while the optical conductivity reduces in the high frequency region.The latter is due to role of electrical field's frequency. 展开更多
关键词 GRAPHENE optical conductivity Holstein model electron-phonon interaction Green's function
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