共查询到20条相似文献,搜索用时 0 毫秒
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The equations governing two-dimensional flux and potential fields in nonlinear soft magnetic materials can be converted into a pair of linear conditions by means of a Legendre transformation. On this basis and for certain classes of constitutive equations, exact solutions are found that describe configurations such as plane multipole fields and fields near corners and edges. In case of perfectly saturable materials the formation of perfectly permeable domains is observed, and their shapes are determined 相似文献
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Olivier Guillon Christian Elsässer Oliver Gutfleisch Jürgen Janek Sandra Korte-Kerzel Dierk Raabe Cynthia A. Volkert 《Materials Today》2018,21(5):527-536
The use of external electric and magnetic fields for the synthesis and processing of inorganic materials such as metals and ceramics has seen renewed interest in recent years. Electromagnetic energy can be utilized in different ways to improve or accelerate phase formation and stabilization, chemical ordering, densification and coarsening of particle-based materials (pore elimination and grain growth), and mechanical deformation (plasticity and creep). In these new synthesis and processing routes, the resulting microstructures and macroscopic material behavior are determined by the interaction of the applied fields with defects such as single or clustered point defects, dislocation networks, and interfaces. Multiscale experimental investigations and modeling are necessary to unveil the mechanisms underlying this field-assisted manipulation of matter. 相似文献
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Radically different effects on materials by separated microwave electric and magnetic fields 总被引:2,自引:0,他引:2
Using a 2.45 GHz wave-guided cavity, in a single mode TE103 excitation, we were able to physically locate compacted 5 mm pellets of samples separately at the H (magnetic) node (where the E field is nearly zero), or the E (electric) node (where H field is nearly zero). A preliminary survey of a variety of metals, (Cu, Fe, Co..) ceramics (ZnO, etc.), and composites,
(WC-Co, ZnO-Co) showed remarkable differences in their heating behaviors. The results establish conclusively that the magnetic
field interaction contributes greatly to microwave heating of common materials in a manner, previously neglected in most theories
of microwave heating, albeit still to be understood.
Received: 15 June 2001 / Accepted: 15 June 2001 相似文献
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AbstractAn in situ microscopic observation of the magnetic orientation process of feeble magnetic fibers was carried out under high magnetic fields of up to 10 T using a scanning laser microscope. In the experiment, carbon fibers and needle-like titania fibers with a length of 1 to 20 μm were used. The fibers were observed to gradually orient their axes parallel to the direction of the magnetic field. The orientation behavior of the sample fibers was evaluated on the basis of the measured duration required for a certain angular variation. As predicted from the theoretical consideration, it was confirmed that the duration required for a certain angular variation normalized by the viscosity of the fluid is described as a function of the fiber length. The results obtained here appear useful for the consideration of the magnetic orientation of materials suspended in a static fluid. 相似文献
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A procedure for analyzing moiré fringe patterns using boundary elements is presented. The kernels of the boundary integrals are based on anisotropic elastic Green's functions developed for bimaterial problems. The interfacial boundary conditions are incorporated in the Green's functions so the interface does not require discretization. The bimaterial kernels are also appropriate for homogeneous problems as well as degenerate isotropic problems. The moiré fringe data provide full-field displacement information and are analyzed in a least-squares sense. The numerical procedure is shown to be a logical extension of the local collocation method developed for linear elastic fracture mechanics. An example is given to investigate convergence of the method, predictions of stress, and to investigate factors influencing the analysis. It is shown that moiré fields associated with both displacement components are needed for an accurate analysis. 相似文献
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John A. Macbain 《International journal for numerical methods in engineering》1983,19(7):1033-1045
The nonlinear diffusion equation as applied to two-dimensional time-dependent magnetic fields is solved with a finite element algorithm. This algorithm permits the analysis of problems possessing complex geometries, induced eddy currents, permanent magnets, and nonperiodic excitation currents. The numerical procedure utilizes implicit time stepping with an iterative scheme to solve the resulting set of equations. Two examples of applications of this program are presented. 相似文献
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Eddy current effects in nonlinear ferromagnetic materials in the presence of a supplementary DC magnetic field are analyzed. The analysis is for a one-dimensional configuration, a semi-infinite plate magnetized homogeneously in a direction parallel to its surface. The nonlinear magnetization characteristic of the ferromagnetic plate material is assumed to be of a step-function form. Solutions of the electric field intensity on the plate surface, the penetration depth of eddy currents in the plate, the eddy current losses, and surface impedance in the presence of a DC magnetic field are obtained. A connection is found between the values obtained in simultaneous DC and AC magnetization conditions and the values obtained in the case of only AC magnetic field excitation.<> 相似文献
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为了确定磁场对铝合金凝固过程的影响,利用双电桥测试了Al-21%Cu、Al-22Si合金分别在无磁场、直流磁场和交流磁场作用下从液态到固态的电阻变化.分析了Al-Cu合金与Al-Si合金电阻-温度曲线的差别,研究了磁场对合金凝固过程中液、固相线温度及微观结构的影响.结果表明,Al-21%Cu合金的电阻-温度曲线呈单调下降趋势,且有两个明显的转折点,而Al-22%Si合金的电阻-温度曲线不再是单调下降,两个转折点也很不明显,在直流磁场作用下,Al-21%Cu、Al-22%Si合金的液相线、固相线温度均有所降低,在交流磁场作用下,两种铝合金的液、固相线温度均有所升高.在Al-Si合金凝固过程中施加外磁场时,抑制了初生β-Si的生成. 相似文献
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A solution of the heat transfer equation for polymer heat-protective materials is presented for the case where three characteristic zones are established. The calculation includes the variation of thermophysical characteristics as a function of temperature and porosity of the material.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 25, No. 5, pp. 827–836, November, 1973. 相似文献
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V. L. Strakhov N. G. Chubakov 《Journal of Engineering Physics and Thermophysics》1983,45(3):1054-1060
A method is outlined for calculating the nonsteady temperature fields in polymer materials swelling on heating and passing through a plastic state in the region of thermal decomposition. 相似文献
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B. L. Mordike 《Progress in Materials Science》1997,42(1-4):357-372
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