This paper presents an operating analysis of ferrite orthogonal-core for high frequency power control and power conversion. The analysis is based on the three-dimensional magnetic circuit of the orthogonal-core, and is called reluctance network analysis. The magnetization characteristics of the ferrite orthogonal-core are calculated accurately by using the reluctance network analysis. On the basis of the obtained magnetization curves, we can analyze the operating characteristics of the various application circuits of the orthogonal-core. For an example, the control characteristics of high frequency variable inductor using the ferrite orthogonal-core are calculated in this paper.

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In the present paper, we have proposed an approach of the leakage magnetic field source searching of a micro processing unit (MPU)on a practical printed circuit board (PCB)from a locally magnetic field distribution. At first, the Fourier multi-resolution analysis was applied to locally measured magnetic field distributions. Secondly, we have calculated a current distribution by using a new approach based on the minimum norm method. Numerical simulations were carried out in order to verify our approach. As a result, the results have verified that the approach is capable of applying to the magnetic field source searching of the practical PCBs.

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The wavelet matrix transform approach, in combination with the conventional method of moments, is applied to solve the electromagnetic scattering problem by a dielectric cylinder. First, the problem is formulated by the integral equation for the field of a harmonic source in the presence of the cylinder. Then the equation is discretized to obtain a dense matrix equation by dividing the cylinder into square cells which are small enough so that the field intensity is nearly uniform in each cell. Finally, the wavelet matrix transform is applied to produce a sparse matrix equation which is treated effectively by a sparse linear system solver.

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Using the network analyzer, we investigated electrical characteristics of printed circuit boards (PCBs) which consist of a coil-shaped conductor and two ground planes (top and bottom). We compared S-parameters for various types of PCBs with different shapes of the coiled conductors with and without Ni-Zn ferrite composite material. From the measured S11s, the equivalent inductances of the coiled conductors were evaluated. Furthermore, using the measured S-parameters, we evaluated the effective relative permeability and permittivity of the insulator inside of PCBs. We found that for the measured frequency range, it is needed to consider PCBs investigated as transmission lines and the equivalent inductances of the coiled conductors hardly depend on their shapes. Power was more absorbed in a PCB with Ni-Zn ferrite composite material than that without the composite material.

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TDEM method is a popular used method in exploration geophysics. The method detects the underground resistivity structures by analyzing the transient phenomena of the EM field occurred when the source current is rapidly shut out. A problem that we often embarrassed is that the above surface measurements failed to detect the structures in the depth in case that the near surface layer were conductive. To solve this problem EM tomography measuring system is suggested, which, by putting the sensor through borehole into the subsurface, extended our measuring domain from two to three dimension. This is a leading edge in this field under its developing way.
Before we can make the EM tomography system a practical one in exploration, many questions have to be answered, such as where could we expect the most efficient measuring and in what span of the measuring time should we take to achieve that. These are all the basic matter for us in designing the system and should be clarified by numerical simulation. In this study, whole set of equations is derived by directly solving Maxwell's equation under correspondent boundary conditions. According to which the propagating behaviors of the EM field in layered earth are simulated. By summarizing the results in a series figures, the essences of equivalent-layer problems are discussed. The superiority of TDEM tomography system is clarified. To evaluate the measuring system's efficiency, a new concept called detectability is introduced. All these provided a convenient criterion in designing our new EM system.

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A new concept is introduced to extract the essential and distinct characteristics of the magnetic field distributions. A key idea is to calculate an eigen pattern, which can represent the characteristics of magnetic fields independent of their resolutions and space positions. The eigen pattern of a magnetic field distribution is obtained by projecting the three orthogonal magnetic field vector components at each of the space coordinates onto the x-, y- and z-magnetic field components coordinate system. Thereby, this projection is possible to remove the space coordinate information, and extract the essential vector characteristics of the target magnetic field distribution. As a result, we have succeeded in identifying and recovering the magnetic field distributions with high resolution.

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Recently, faulty operation by mutual interference among electric and electronic devices has become a social problem, which is caused by widely spread personal computers and cellular phones. A solution to overcome this difficulty is to estimate the current distributions from locally measured magnetic fields.
In this paper, we propose two methods, one is the direct inverse method and the other is the generalized vector sampled pattern matching (GVSPM in short) method, for estimating the current distributions in a square cubic box. First, we solve inverse source problems in order to estimate the 2D current distributions from locally measured 2D magnetic fields. Second, we combine the estimated 2D current distributions to obtain quasi-3D current distributions. Preliminary experimental results indicate the validity of the proposed methods.

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Dynamic images such as computer graphics animation, moving things captured by video camera are always composed of several images as frames. This paper proposes one of the mathematical formulations for such animations. The key idea of our formulation is that each of the pixels representing an image is regarded as a kind of potentials in vector fields. Based on the vector calculus in classical physics, any static and dynamic images can be represented by the Poisson- and Helmholtz- type partial differential equations, respectively. This makes it possible to handle any images as analytical and continuous quantity even though these are given in terms of the discrete ones.
Further, it is clarified that the animation technology is closely related with the simulation one. In the present paper, we carry out one of the simulations for magnetodynamic fields in ferro-magnetic material to show the relationship between the animation and simulation methodologies. As a result, it is demonstrated that our animation methodology reproduces the simulated magnetodynamic fields. Thus, it is found that our approach has versatile capability for analyzing the electric and electronic devices.

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Modern electronics are always composed of the printed circuit board (PCB). When the currents on the PCB are visualized without decomposing the electronic devices, the testing and inspecting of the electronic devices can be carried out in an extremely efficient manner.
This paper proposes one of the methodologies to visualize a current distribution on the PCB from the locally measured magnetic fields. The current visualization from the magnetic fields always results in a solution of the ill-posed inverse problem. This paper reveals that conventional least squares method gives a reasonable solution of the inverse problem. Thus, we have succeeded in realizing a nondestructive testing methodology with high reliability.

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Zinc Oxide (ZnO) elements which have non-linear current-voltage characteristic have a number of failure mechanisms when ZnO elements absorb surge energies. Failure mode at the edge of the metal sprayed electrode are among the most common failure mechanisms at high current surges. Such failures take the form of a melt pinhole from the electrode edge to the counter electrode or the side surface of the disk element. As a result of the measurement of the resistively-temperature characteristic at high current region and the computation of the electric and thermal field distribution, it was made clear that the failure at the electrode edge was caused by the partial melting by the current concentration and the local thermal runaway at the electrode edge. Moreover, the current concentration was reduced by the decreasing of the distance between the electrode edge and the sintered ZnO body.
We developed the metal sprayed electrode manufacturing process which could control the edge margin. And using this electrode process, the energy absorption capability of the ZnO elements was improved largely by reducing the current concentration at the electrode edge.

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This paper deals with the influence of interface between polyethylene and semiconducting electrode on the space charge formation and electrical breakdown. Low-density polyethylene (LDPE) films attached with different semiconducting electrodes were subjected to the DC breakdown test, and corresponding space charge distribution was measured.
A heat treatment to LDPE itself did not bring about a significant change in space charge profile, however, when a semiconducting electrode was hot-pressed, the impurities would migrate into LDPE at high temperature, leading to the change in space charge profile. Furthermore, it was suggested from the comparison between the results with degassed and asreceived semiconducting electrodes, that some carriers relating to impurities in the electrode would move into LDPE under the voltage. In addition, It was shown that the breakdown is not determined by the field at the cathode which can supply sufficient electrons, but by the maximum field across the specimen, suggesting that an increase in conduction current due to the generation and/or injection, rather than the electronic avalanche process, leads to the breakdown.

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Hydrogenated amorphous silicon-germanium (a-SiGe:H) alloys have been attracting much attention in application to solar cells. Plasma CVD technique is widely used to deposit the a-SiGe films. Thus it is very important to understand the relationship among the film deposition conditions, the properties of films and the plasma parameters. In this study, SiH₄-GeH₄-H₂ mixture gases were decomposed in a parallel plane electrode system with 13.56MHz radio frequency glow discharges. The plasma parameters such as electron temperature and density were measured by floating double probe method. We studied a-SiGe films with an optical gap of 1.6eV, and the following results were obtained:
a) Substrate temperature is the most important deposition parameter to improve the quality of a-SiGe film.
b) Plasma parameters affect the film deposition rate, but influence on film quality is not large.
c) "Ion damage" is small under the deposition conditions for obtaining device-grade a-SiGe films.

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Metal vapor plasma generated from a vacuum arc discharge expands into the surrounding space. The purpose of the present study is to know the basic physical properties and propagation characteristics of the metal vapor plasma generated from a short burning time impulse arc and to understand the relation between them. Here, lead cathode is used and lead ion plasma generated from an impulse arc with a burning time of 13 μs is taken as the research objective. The propagation velocity, electron temperature, electron density and potential of the expanding plasma are measured using an ordinary probe method. Spatial and time dependencies of the charge state distribution of lead ions in the expanding plasma are measured using Time of Flight method, and retarding effect of the grid potential against the propagation of the plasma is investigated.

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