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51.
52.
A novel method of computing the nonlinear differential equations relating to the transient behaviour of an induction motor using a polynomial series, is presented. The stator and rotor currents and the angle of rotation are expressed as polynomial series dependent on time. These are then substituted into the differential equations of the induction motor to compute the polynomial coefficients and, consequently, the transient quantities. Since the equations are nonlinear, the computations are carried out using the step-by-step method. The stator and rotor currents, speed and torque are calculated for acceleration and braking conditions. The results are compared both analytically and experimentally. 相似文献
53.
An in-depth investigation is made on the problem of an arc-shaped interface insulating crack in a three-phase concentric circular
cylindrical piezoelectric composite constitutive model. An exact solution in series form is derived by employing the complex
variable method. In addition, the distribution of physical quantities such as stresses, strains, electric displacements and
electric fields in the whole field and along the interface is also presented. Explicit expressions for crack opening displacement,
jump in electric potential on the crack surface and the electro-elastic field intensity factors at the crack tips are obtained.
Specific calculations demonstrate that the convergence of the series form solution is satisfactory and that the outer phase
(composite phase) will exert a significant effect on the electro-mechanical coupling response of the composite system. Owing
to the fact that stresses and electric displacements still possess conventional inverse square root singularities, the oscillating
singularities near the crack tip under plane strain conditions will be absent and, as a result, no unphysical interpenetration
phenomenon of the two crack surfaces will occur. In conclusion, the elastic solution obtained is also based on a solid physical
foundation.
Project supported by the National Natural Science Foundation of China (No.59635140), and the Doctorate Foundation of Xi'an
Jiaotong University. 相似文献
54.
Kinesin is a two-headed biological molecular motor that can walk processively on microtubule via consumption of ATP molecules. The central issue for the molecular motor is how the chemical energy released from ATP hydrolysis is converted to the kinetic energy of the mechanical motion, namely the mechanism of chemomechanical coupling. To address the issue, diverse experimental methods have been employed and a lot of models have been proposed. This review focuses on the proposed models as well as the qualitative and quantitative comparisons between the results derived from the models and those from the structural, biochemical and single-molecule experimental studies. 相似文献
55.
HL-2M 装置供电系统研制 总被引:2,自引:0,他引:2
为满足 HL-2M 装置的供电需求,须配套建设相应的供电系统。通过仿真计算 HL-2M 装置的总体供 电需求,考虑到 HL-2A 装置现有的供电系统设备,提出了兼顾 HL-2A 和 HL-2M 装置供电需求的总体配置方案。介绍了国内首台 300MVA 立式交流脉冲发电机组、磁体电源、高压电源和电源控制系统的研制情况。 相似文献
56.
Luis Amezquita-Brooks Eduardo Liceaga-Castro Jesus Liceaga-Castro 《Applied Mathematical Modelling》2014
The stator currents subsystem is a vital element of many high-performance induction motor control schemes. While there are several control techniques available for this subsystem, traditional linear controllers are still widely used because of its simplicity and proven effectiveness. However, the traditional simplified design-model lacks important information, necessary for the design of high-performance and robust controllers. In this article a novel design-model intended for linear controller formulation and evaluation is developed. This new mathematical representation captures several elements which are missing in the traditional representation, maintaining at the same time a similar level of simplicity. Along the derivation of this new representation several models of decreasing complexity and comprehensiveness are also presented together with a critical classification. This classification is intended to aid the designer in choosing the appropriate mathematical representation for specific purposes. Finally, the article is accompanied with experimental findings which illustrate the use of the proposed model. 相似文献
57.
针对固体火箭发动机环境载荷的诸多不确定性,提出了环境载荷FHW量化评估算法.对比分析了火箭发动机的典型环境条件及其影响,采用熵值法确定了指标权重,基于FHW方法建立了火箭发动机的环境载荷评估模型,根据环境因素的分布特征给出评估指标的隶属函数,并获取其相应的灰色关联系数.算例验证了不同环境载荷因素对火箭发动机的影响程度,结果表明FHW评估策略和算法简单易行、精度高,在装备环境载荷量化评估中具有参考和应用价值. 相似文献
58.
Frommer's nonlinear multisplitting methods for solving nonlinear systems of equations are extended to the asynchronous setting. Block methods are extended to include overlap as well. Several specific cases are discussed. Sufficient conditions to guarantee their local convergence are given. A numerical example is presented illustrating the performance of the new approach. 相似文献
59.
The electric field of the microtubule is calculated according to its dipole distribution. The conformationalchange of a molecular motor is described by the rotation ofa dipole which interacts with the microtubulc. The mricalsimulation for the particle current shows that this interaction helps to produce a directional motion along the microtubule.And tte average displacement executes step changes that resemble the experimental result for kinesin motors. 相似文献
60.
Molecular motor cycles are studied in the framework of stochastic ratchets in which the motor moves along a 1-dimensional track, can attain M internal states, and can undergo transitions between these levels at K spatial positions. These ratchets can be mapped onto a stochastic network of KM discrete states. The network is governed by a Master equation, fulfills a vertex rule, and satisfies detailed balance in the absence of enzymatic activity and external force. Any pathway of the motor cycle which leads to a forward or backward step of the motor corresponds to a certain sequence of transitions spanning this network. The dependence of the motor velocity on the transition rates can be determined for arbitrary values of K and M and exhibits some simple and universal features. 相似文献