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We investigated the dc magnetic field and temperature dependences of the microwave intrinsic surface resistance (Rsint) of YBa2Cu3Oy (YBCO) superconducting thin films with various thicknesses. We used YBCO films from 100, 200, and 300 nm thick YBCO films deposited on CeO2/Al2O3 substrates. The Rsint is means the surface resistance of YBCO film without the dielectric loss of the substrates. The Rsint was obtained from measured surface resistance (Rs) by using a phenomenological equation. The Rs was measured using the dielectric resonator method at 21.8 GHz. A dc magnetic field of up to 5.0 T was applied parallel to the c-axis of the superconducting thin films during the Rs measurements. The Rsint of the YBCO thin films increased when the dc magnetic field was applied. These relations could be explained with the two-fluid model for high-frequency and high-magnetic field limits. The Rsint ratio (defined as Rsint (5T)/Rsint (0T)) slightly decreased with the film thickness. These results indicate that the Rsint of HTS films depends on the film thickness in the dc magnetic field and the Rsint in a dc magnetic field may be related to the pinning center in the HTS films.

The eddy-current type proximity sensor is a noncontact type sensing device to detect the approach of a conductor by increase of coil resistance due to eddy-current loss. This paper proposes to add the cap-shaped magnetic flux shield at the top of the ferrite core for the actual sensor. In conventional proximity sensors, main magnetic flux path passes through the air between the target conductor and ferrite core. The proposed sensor, in contrast, has closed magnetic circuit geometry. This means that main magnetic flux path is almost completed by the core and the shield. Therefore, it is predicted that flux does not reach the target conductor and it causes debasement of sensing property. However, it is shown that the calculated results by finite element method and measured results of the sensing property of the proposed sensor is enhanced compared with the actual sensor. This paper quantitatively accounts the electromagnetisms of the proposed sensor from sensing property, flux distributions, and eddy-current loss in each part of the sensor body

Eddy-current-type proximity sensor is a noncontact-type sensing device to detect the approach of a conductor by an increase of coil resistance due to eddy current loss. This paper investigates electromagnetic (EM) characteristics of the actual proximity sensor by the finite-element method and provides knowledge to enhance sensing property. In particular, the influence of eddy current loss to sensing property is shown and quantitatively estimated. Furthermore, modified models of the actual sensor are proposed and calculated as numerical experiments. As a result, enhanced sensing properties of the proposed models are shown

The authors have discussed the numerical simulation method for transient electromagnetic fields using the boundary element method which is based on scalar and vector potentials. To use the BEM which is based on potentials to transient electromagnetic fields, a special gauge transformation has been performed to get an appropriate boundary condition for potentials. This paper discusses a restriction on the topological configuration of the considered region, that is necessitated by the use of the gauge transformation. The discussion is done using the four-dimensional space-time formulation. It is shown that the BEM which is based on potentials is almost free from a topological restriction on the considered region.

Many authors have been discussing numerical simulation methods of transient electromagnetic fields based on scalar and vector potentials and have shown that the Dirichlet type boundary conditions can be imposed on the potentials. Based on the gauge selection, some numerical simulations (BEM analysis) have been done. However, the numerical simulations often encountered numerical instabilities. To clarify the stable condition, this paper discusses numerical instabilities of the BE analysis of transient electromagnetic fields. Then, it is pointed out that there are two kinds of numerical instabilities, short and long range instabilities.

This paper presents a boundary element analysis of transmission-line parameters on the basis of the quasi-TEM assumption. Singular boundary elements are employed to adequately express the corner singularities at sharp conductor edges. The boundary integrals consisting of the Green's function and singular interpolation functions are regularized by a Taylor expansion technique, and are then evaluated using the standard Gaussian quadrature. The numerical results for test problems show the reliability of the present method.

This paper describes a two-dimensional analysis of magnetic fields with thin magnetic materials using hypersingular integral equations. In this analysis, the thin materials are modeled as infinitesimally thin sheets, on which hypersingular integral equations for the vector potential are formulated. The hypersingular integral equation is discretized by a boundary element method, on the basis of the Hadamard finite part integral, to numerically compute magnetic fields. The present method is shown to give an accurate magnetic field in a cylindrical magnetic shell with linear permeability. Moreover, numerical results for the shell with non-linear permeability are provided.

Stable levitation with a permanent magnet and a bulk high T/sub c/ superconductor (HTSC) is examined numerically by using the critical state model and the frozen field model. Differences between a permanent magnet and a trapped field magnet are discussed in terms of the levitation force property. The stable levitation region of the HTSC on a ring magnet and on a solenoid coil are calculated using numerical methods. The obtained results are discussed from the point of view of differences in magnetic field configuration. >

Levitation force between permanent magnets and high-T/sub c/ superconductors (HTSC's) is evaluated numerically based on the critical state model. The bulk HTSC is approximated to a thin plate multilayer model from its anisotropic structure. The thin plate eddy current code with the finite element method is applied to the analysis of the HTSC flywheel, where ring magnets and the HTSC are arranged in triple concentric circles. The size and the combination of the magnets are examined to obtain the large levitation force. It is shown that the levitation force of the HTSC flywheel depends strongly on the magnetic field configuration. >

The scalar Helmholtz equations are investigated by using the integral equation method (IEM). In the IEM analysis, the fundamental solution of the Laplace equation is used as a weighting function. Two IEM formulations are obtained: one is a standard formulation and the other is obtained from an elimination of the unknown boundary value. The accuracy and computational time of the IEM are compared with those of the finite element method in two dimensional scalar Helmholtz problems. The analysis of a resonant cavity is reduced to a simple eigenvalue problem. Resonant frequencies of the IEM agree well with those of the finite difference method. Usefulness of the IEM is confirmed through the analyses of the scalar Helmholtz equations. >

Dispersion relations of toroidal plasma-surface waves are studied by using the boundary element method for cold plasmas in a quasi-electrostatic state. When sinusoidal waves are assumed for the toroidal direction, a governing equation becomes the axisymmetric modified Helmholtz equation. Application of boundary conditions reduces the study to an analysis of an eigenvalue problem. Fundamental solutions that are used in the analysis depend on the toroidal mode number of the surface waves. Dispersion relations of circular cross-sectional plasmas are in good agreement with exact solutions for parameters of toroidal modes, poloidal modes, and the aspect ratio. Effects of the elongation ratio on the dispersion relations are also studied in the analysis of toroidal plasma with an oval cross section. >

Eleetroless plated CoB films were plated in a bath with dimethylamineborane (DMAB) as a reducing agent. The magnetic properties of films changed widely with changes in the concentration of the complexing agent in the bath, such as ammonium sulfate or sodium tartrate. Film with the lowest coercivity was obtained from the bath containing 0.3 mol/dm3 of sodium sulfate and 0.55 mol/dm3 of sodium tartrate. Structural analysis of this film by electron microscopy revealed that the film consists of fine, highly crystalline particles with the hep structure.

We investigated the effect of introducing artificial pinning centers (APCs) into YBa2Cu3O7-δ (YBCO) thin films to reduce the microwave surface resistance (Rs) in a high dc magnetic field for high-performance microwave devices with high-quality factor (Q). YBCO thin films with and without APCs were deposited on MgO(100) substrates by using the pulsed laser deposition technique. We used commercial 0, 1.5, 3.0 wt% BaMO3 (BMO, M = Zr, Hf) doped YBCO targets. The δω and δφ of the YBCO thin films increased as BMO doping increased, and the rate of increase appeared to be smaller for BHO doping than for BZO doping. The Rs of these thin films was measured at 21.8 GHz with the dielectric resonator method and a dc magnetic field of up to 5.0 T was applied parallel to the c-axis of the YBCO thin films during the Rs measurements. The Rs of the BMO doped films in the magnetic field was smaller than that of the pure YBCO films. In particular the Rs of the 1.5 wt% BHO doped films was the smallest among all of the films, about half compared with that of the Rs of the pure YBCO films at 4 T and 20 K. As a result, we found that introducing APCs into YBCO thin films is effective for decreasing Rs under a dc magnetic field.

An RFQ linac 'LITL' (Lithium Ion Test Linac) was constructed and accelerated ion beams of H+, H+2, H+3, 3He+, 6Li+ and 7Li+. The machine was designed to accelerate particles with charge to mass ratio (q/A) of 1 ~ 1/7 injected at 5 keV/u up to 138 keV/u. The acceleration cavity of four vane structure is 56 cm in diameter and 138 cm in length. Transmission exceeding 90 % has been obtained for proton beam of 80 ?A. The acceleration characteristics agree well with the computer simulation with PARMTEQ. For the acceleration of 7Li+, an rf power of 22 kW is fed with a loop coupler. In cw operation, an electric field of 205 kV/cm has been applied, which is required for 7Li+ acceleration and corresponds to 1.8 times the Kilpatrick's criterion. A maximum field of 2.0 times the criterion has been achieved, in pulse operation, with a duration width of 5 ms and repetition period of 25 ms. Operation of the machine is easy and stable.

The INS SF cyclotron is a multi-particle variable-energy accelerator and has been in operation since 1974. The maximum energy usable for experiments is 35 MeV for protons, 34 MeV for deuterons, 90 MeV for 3He and 68 MeV for ?-particles. Up to 8 ?A of these beams are extracted. A cold cathode PIG source for heavy ions was developed and extracted beams of 4.3 ?A 14N5+ and 1.5 ?A 20RNe6+ are obtained. Polarized protons are axially injected and about 15 nA are deflected. The beam transport system consists of low, medium and high resolution courses. Eleven target stations are available for experiments and eight of them are ready for use. The high resolution course is a double monochrometer system, which can also be operated in a non-dispersive mode. This paper describes the beam development since routine operation started.

Beam transport system from the INS-SF cyclotron to the TARN was designed and constructed. The system is composed of optical matching elements, beam monitoring devices and vacuum system. In the present paper, design conception and details of components in the system are described as well as the experimental results of the performance.

In applying a vacuum circuit breaker (VCB) in a nuclear power plant, the nuclear instrumentation equipment could be adversely affected by surges generated rated when the VCB is switched on and off, because the instrumentation cables are installed in a tray stack in parallel with the tray stack in which the high voltage cables are also installed.

This paper describes a new microwave relaying system using traveling-wave tubes (TWT), and utilizing its large inherent frequency bandwidth. In this system, the increased gain is obtained by amplifying the input signal through the TWT Amplifier, and reamplifying it in the same TWTA after heterodyning the frequency to the second frequency. The signal received could be amplified in the same TWTA more than once simultaneously, and the gain of the TWTA would be increased in proportion to the amplifying times. A 4,000-mc band television repeater using three TWT's, and its measured results are also described; we obtain the results that the over-all gain is above 100 db and is steady within ±0.5 db with the frequency bandwidth of 20 mc, and also, the noise figure is below 15 db. The actual test was carried out by putting the equipment in the TV long-distance relay line as a repeater. From this test it was proved that there is no defect of the operation of the amplifier in using TWT as a reflex amplifier. In this new system, the number of TWT's can be reduced one-half to one-third and the cost of a repeater with increased reliability can be lowered.

Mechanical typewriting translators have been widely used for monitoring of Kanji (Chinese character) teleprinter system in newspaper companies despite their substantial disadvantages such as slow typing speed, poor stability, difficult maintenance, and mechanical noise. These disadvantages were completely solved by our electrostatic Kanji teleprinter (Fig. 1) which features high printing speed, reliability, and stability of operation.

Light to heavy ions accelerated by a synchrotron TARN II are planned to be cooled by the electron cooling method. A device to cool these ions up to energies of 200 MeV/A is under construction. The electron energies are variable from 15 to 120 keV and the maximum current density is 0.5 A/cm2. The length of interaction region between electrons and ions is about 1.5 m. Design of the electron guiding coils and high voltage system is described as well as the calculated electron trajectories. The status and prospect for the cooling project are given.

By using a rapid quenching method, Fe-Go-Si alloy ribbons were prepared and their grain structure and magnetic properties were observed. The size of ribbons obtained are 50∼70 μm in thickness and 2 ∼4 mm in width and their average grain size is 2∼ 20 μm. By annealing ribbons in a vacuum atmosphere the grain grew to be about 1∼2 mm and the ribbons had