International Journal of Applied Electromagnetics and Mechanics - Volume 14, issue 1-4

Article Type: Editorial

Abstract: Preface to the Proceedings of the tenth International Symposium on Applied Electromagnetics and Mechanics ISEM-Tokyo

DOI: 10.3233/JAE-2002-524

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 1-2, 2002

Authors: Hantila, F. | Cranganu-Cretu, B. | Preda, G. | Miya, K.

Article Type: Research Article

Abstract: The aim is to report a very efficient approach to force calculation on ferromagnetic, rigid, movable parts of electromechanical systems. The constitutive relationships of the movable parts are nonlinear. Proof of the formula is based on the virtual work method for the co-energy of the system.

DOI: 10.3233/JAE-2002-365

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 3-8, 2002

Authors: Fujisaki, Keisuke

Article Type: Research Article

Abstract: 3-D magnetohydrodynamic calculation model taking into consideration of heat transfer and solidification as well as free surface is developed in order to evaluate the characteristics of molten metal using electromagnetic stirring (EMS). A shadow method that calculates electromagnetic force in consideration of free surface transition is proposed to reduce computing time and keep sufficient accuracy. A calculated free surface of Mercury under 200 Hz magnetic field shows an adequate agreement with experimental one. Calculation …results applied to continuous casting process taking into consideration of heat transfer and solidification are in good agreement with operation data. This model introduces that EMS makes the solidified shell uniform and dynamic deviation of temperature stable. Show more

DOI: 10.3233/JAE-2002-356

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 9-14, 2002

Authors: Igarashi, Hajime | Honma, Toshihisa

Article Type: Research Article

Abstract: This paper discusses properties of the second-order edge elements for the finite element analysis. It is shown that the condition number, which dominates the convergence of the ICCG method, can be different even for the equivalent second-order elements which have common basis vectors. Moreover the computed eigenvalues and condition numbers of the local and global stiffness matrices are shown to be consistent with the reported convergence of the ICCG method. It is suggested that the spectrum …of the local stiffness matrix is useful for prediction of the ICCG convergence. Show more

DOI: 10.3233/JAE-2002-359

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 15-18, 2002

Authors: Hano, Mitsuo | Miyamura, Takeshi | Hotta, Masashi

Article Type: Research Article

Abstract: Three-dimensional novel mixed-order tetrahedral elements are systematically constructed and applied to the finite element analysis of electromagnetic fields. The degree of freedoms of the shape functions assigned on the six edges are essentially independent with each other. The shape functions on the faces and in the volume are not orthogonal with those of the edges. So, the tetrahedral elements proposed in this paper have six parameters to define the shape functions. A smooth eddy current flow …in the conductor can be obtained, under the condition not to needlessly increase the total number of unknowns. Show more

DOI: 10.3233/JAE-2002-492

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 19-22, 2002

Authors: Fujioka, Takushi

Article Type: Research Article

Abstract: When Electromagnetic fields of Devices are analyzed using anisotropy, in some cases, Forces and Torques should be calculated by the Maxwell's Stress Tensor Method. Then a new anisotropic correction to the Forces and Torques in their cases is introduced and calculated.

DOI: 10.3233/JAE-2002-357

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 23-27, 2002

Authors: Gotoh, Yuji | Takahashi, Norio

Article Type: Research Article

Abstract: The signal of an alternating magnetic flux leakage testing is affected by several factors, such as the buried length from surface, depth of crack. In this paper, the effects of those factors on the flux distribution near a search coil are examined using 3-D nonlinear FEM. It is shown that the leakage flux is produced by the saturation of steel near the surface, if the distance from the surface to a crack is small.

DOI: 10.3233/JAE-2002-350

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 29-34, 2002

Authors: Kanai, Yasushi | Matsubara, Ryo | Muraoka, Hiroaki | Nakamura, Yoshihisa

Article Type: Research Article

Abstract: Finite-element modeling of single pole (SPT) write head with double-layered medium for perpendicular magnetic recording is investigated. In carrying out 3-D eddy current transient finite-element analysis, reducing the medium area is one key factor for computation time reduction while maintaining sufficient solution accuracy. It is also investigated the number of layer divisions for thin metallic under-layer. The results validate the modeling of SPT head with double-layered medium.

Keywords: perpendicular magnetic recording, write heads, high frequency recording, finite element methods, model validation

DOI: 10.3233/JAE-2002-353

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 35-42, 2002

Authors: Enokizono, Masato | Todaka, Takashi | Takahashi, Hideki

Article Type: Research Article

Abstract: The electromagnetic retarders are widespread in heavy vehicle and train industry. The electromagnet type and permanent magnet type retarders are developed at a variety of operating forces to reduce speeds. This paper describes the use of the finite element method with an upwind interpolation function in designing the permanent magnet type retarder. The equation of motion was solved for the analysis of the deceleration process of the conductive plate. The suitable permanent magnet anangements and the …yoke constructions are made clear in the obtained numerical results. Show more

DOI: 10.3233/JAE-2002-354

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 43-46, 2002

Authors: Mukhopadhyay, S.C. | Iwahara, M. | Yamada, S.

Article Type: Research Article

Abstract: For the last few years the authors have been involved in the design and development of different topologies of magnetic current limiter (MCL). The small scale laboratory models have been fabricated and experiments were conducted. The simulated performance obtained from the tableau approach based on lumped parameter model shows discrepancy with the experiment. This paper describes the necessity of electromagnetic field computation which clearly shows the discrepancy between the observed and the simulation results, which …can be attributed to a non uniform flux distribution in the core. Show more

DOI: 10.3233/JAE-2002-346

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 47-50, 2002

Authors: Kanayama, Hiroshi | Tagami, Daisuke | Matsumoto, Satoshi

Article Type: Research Article

Abstract: A large scale computation of three-dimensional eddy current problems is considered. Some techniques are introduced to compute large scale problems; their numbers of degrees of freedom are almost one million. A transformer model is considered as a numerical example.

DOI: 10.3233/JAE-2002-348

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 51-55, 2002

Authors: Mizutani, U. | Ikuta, H. | Oka, T. | Itoh, Y. | Yanagi, Y. | Yoshikawa, M.

Article Type: Research Article

Abstract: We synthesized the c-axis oriented single-domain Ag-bearing Sm123 superconductors with 36~mm in diameter and magnetized them by either static field or single pulsed-field. By using the Sm123 bulk superconductor magnetized by static field, we succeeded in fully magnetizing the Nd-Fe-B plate with 50 × 50 × 5 mm^3 in size by scanning the plate over the bulk superconductor. As another example, we present the construction and performance of a face-to-face superconducting permanent …magnet system, which is driven by magnetizing the Sm123 superconductor cooled to 35 K by the pulsed field technique we developed. Show more

DOI: 10.3233/JAE-2002-398

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 57-63, 2002

Authors: Mamalis, A.G.

Article Type: Research Article

Abstract: High-energy rate powder compaction techniques, like explosive and electromagnetic compaction, may be considered as a tool to produce superconductive ceramics with unique properties. A very great novelty is indicated from the subsequent mechanical processing of the densified high-Tc superconducting ceramics, employed to produce a sound final product. Wires, rods, plates, strips and forged parts with superconducting core and metal sheath can be produced by various techniques, like wire-drawing, extrusion, rolling and forging …and subsequent metal removal processing, e.g. machining and grinding. High temperature superconducting materials possess electrical/electronic and magnetic properties of utmost importance, one of which is the high-current carrying capability of superconductors with small cross sections. Thus, they can be used as power transmission cables or other functional elements in synchronous generators, levitated bearings, flywheels, fault current limiters and electrical switchgears for energy storage. An account of the above mentioned deformation processing of bulk superconductors and its applications is given in this report. Show more

DOI: 10.3233/JAE-2002-400

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 65-74, 2002

Authors: Mahel, Michal

Article Type: Research Article

Abstract: We present the experimental results of the AC susceptibility of YBaCuO. Presence of magnetic hysteretic features is analyzed and ascribed to granular nature of YBaCuO. We discuss the necessity of treating the high-temperature superconductor as a granular-like system with grains embedded in a weakly superconducting host.

DOI: 10.3233/JAE-2002-392

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 75-80, 2002

Authors: Hashizume, Hidetoshi | Suzuki, Manabu | Toda, Saburo

Article Type: Research Article

Abstract: A new two-dimensional model for electromagnetic field analysis is proposed to evaluate the current distributions in high critical temperature superconducting filament. The model is based on the results calculated by exact three-dimensional analysis. By using the new model, quench propagation is evaluated, which shows more robustness against the quench propagation.

DOI: 10.3233/JAE-2002-396

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 81-84, 2002

Authors: Ito, S. | Hashizume, H. | Kitajima, S.

Article Type: Research Article

Abstract: In the present design, the superconducting magnets can not be separated into several parts of the magnet, because of problems caused by heat generation and electromagnetic force. For the future commercial fusion reactor, however, the mountable magnets are desired to make the reactor maintenance and repair easy. In this research, therefore, a study on mechanical jointing of HTc S.C. will be performed to clarify its possibility. Two methods of the jointing are employed to compare the …results. In the first method a piece of S.C. tape is put on another tape where the stress between two tapes is controlled. In the second method cross sections of two S.C. tapes are directly jointed. The voltage drop is measured to estimate the resistance in those regions and the possibility of jointing is discussed. Show more

DOI: 10.3233/JAE-2002-397

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 85-88, 2002

Authors: Meerovich, V. | Sokolovsky, V. | Vajda, I.

Article Type: Research Article

Abstract: The paper presents the experimental results showing a specific behavior of high-temperature superconductors in various electric circuits. Self-oscillations of temperature and current in the superconductor manifest themselves as sharp peaks of voltage across the superconductor on the background of a basic signal. It is shown that these oscillations can also appear when a superconductor is in flux creep regime. In inhomogeneous superconducting samples, the oscillations are associated with cyclic movement of normal …or resistive zones. Show more

Keywords: high temperature superconductor, self-oscillation, superconducting thin film

DOI: 10.3233/JAE-2002-399

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 89-94, 2002

Authors: Fukuoka, Katsuhiro | Hashimoto, Mitsuo

Article Type: Research Article

Abstract: The magnetic shielding is used as one of applications of the high-T c superconductor (HTS). Magnetic characteristics of the HTS are not uniform, since it has grain boundaries and cracks (weak links). Thus, the evaluation of the magnetic flux invasion by the flux flow into the HTS is important. In this research, magnetic characteristics of the HTS on AC magnetic field from 1 to 250~Hz were evaluated. From these experiments, we were able to understand …that the polycrystal HTS had high magnetic shielding performance at the higher frequency, even if it contains a lot of weak links. Show more

DOI: 10.3233/JAE-2002-394

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 95-99, 2002

Authors: Kamijo, Hiroki | Fujimoto, Hiroyuki

Article Type: Research Article

Abstract: We have fabricated a 198 mm × 99 mm bulkmagnet consisting of arrayed melt-processed Y-Ba-Cu-O bulk superconductors that are 33 mm × 33 mm in size and 10 mm in thickness, and magnetized it by the field-cooling method. The magnetic field distribution of the bulkmagnet may be controlled by changing the bulk superconductor arrangement, because a number of bulk superconductors are arrayed in rows and columns. In this study, we performed flux-trapping experiments of the …mini-bulkmagnet for three different bulk superconductor arrangements. As a result, it was proved that the magnetic field distribution could be controlled by changing the bulk superconductor arrangement. Show more

DOI: 10.3233/JAE-2002-395

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 101-106, 2002

Authors: Tachi, Yasuharu | Nishikawa, Tsuyoshi | Sawa, Koichiro | Murakami, Masato | Iwasa, Yukikazu

Article Type: Research Article

Abstract: We have directly measured the levitation force of levitated bulk superconductors in an electromaglev system. The levitation force had a hysteresis loop during increasing and decreasing field processes. Such a hysteretic behavior can be explained in terms of hysteretic penetration of external field to the superconductor. Based on such magnetization, we performed numerical simulations of the levitation forces, which were in fairly good agreement with experimental data.

DOI: 10.3233/JAE-2002-393

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 107-113, 2002

Authors: Ishigohka, Takeshi | Ninomiya, Akira | Hayakawa, Kihachiro | Mitsuhashi, Tsukasa

Article Type: Research Article

Abstract: In order to examine the fundamental availability of a homopolar machine with laminated armature rotor disks, the authors fabricated and tested a small superconducting experimental homopolar machine with two rotor disks. The machine was tested as a generator. The obtained experimental data show that the output voltage of the 2-disk machine is about 2 times larger than that of the 1-disk machine. From this experimental result, we can conclude that the output voltage of a homopolar …generator with axially laminated rotor disks is proportional to the number of the disks. Show more

DOI: 10.3233/JAE-2002-390

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 115-120, 2002

Authors: Vajda, I. | Györe, A. | Porjesz, T. | Sokolovsky, V. | Meerovich, V.

Article Type: Research Article

Abstract: The concept of an all-superconducting (AS) mini power plant (MPP) model is presented. An experimental HTS fault current limiter (FCL) for the protection of the generator unit of the AS MPP model was designed. During its lifetime the HTS FCL can be activated thousands of times. Duration tests were performed on the HTS FCL to determine the dependence of the value of the limited current and the voltage of the FCL on the number of activations of the …device. The experiments have shown that the parameters of the HTS FCL are approximately constant after three thousand activations. This result indicates that the relevant parameters of the HTS ring used in the device are approximately constant, and that the FCL can be designed and used in the network with predictable parameters. Show more

Keywords: high temperature superconductor, fault current limiter, mini power plant

DOI: 10.3233/JAE-2002-493

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 121-126, 2002

Authors: Demachi, Kazuyuki | Miura, Akira | Sawada, Akihiko | Miya, Kenzo | Higasa, Hiromasa | Takahata, Ryoichi | Kameno, Hiroo

Article Type: Research Article

Abstract: The degradation of rotation speed is one of the most significant problems for the practical use of superconducting magnetic bearing (SMB) for flywheel energy storage system. This is called the rotation loss. This phenomena is caused by the AC magnetic field due to the inhomogeneous distribution of magnetic flux density on the permanent magnet (PM) rotor. In this research, our simulation method was improved so that the 3-dimensional rotational dynamics was taken into account.

DOI: 10.3233/JAE-2002-391

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 127-132, 2002

Authors: Weiland, Thomas | Schuhmann, Rolf

Article Type: Research Article

Abstract: The quality of particle beams depends strongly on the quality of the accelerator. The major components of particle accelerators are beam optics elements such as quadrupole magnets, bending magnets and accelerating structures such as RF-cavities. The numerical field analysis of magnetic elements is well advanced and has become a standard tool in virtually any accelerator design. In this area there is only little progress to report as only in very specialized areas remains some need for …new research. This is however not the case for the design procedures of accelerating structures. With the ever increasing demands for higher energy and very high quality beams the demands for electromagnetic design tools is drastically increasing. In this paper we focus on the latest developments in the area of high precision field computation and discuss new developments for the analysis of parasitic trapped modes. Show more

DOI: 10.3233/JAE-2002-368

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 133-142, 2002

Authors: Kobayashi, T. | Muroya, Y. | Watanabe, T. | Ueda, T. | Yoshii, K. | Uesaka, M. | Katsumura, Y. | Nakajima, K. | Zhu, X.

Article Type: Research Article

Abstract: For a sub-picosecond pump-and-probe-type radiation chemistry work, a new synchronized electron linac and laser system was installed in Nuclear Engineering Research Laboratory (NERL) of University of Tokyo. The new 0.3 TW laser system with a Ti:Sapphire oscillator (795 nm) and amplifiers generate 300 ps pulses at 10 Hz at first. The laser is splitted into the two beams. The first is compressed to 4 ∼ 11 ps so as to drive the RF-Gun and generate a …pump-electron-beam. The second is compressed to 100 fs and used for the probe-light. The drive laser is converted to the third harmonics (265 nm, < 250 μJ). Moreover, a new 15 MW klystron was installed for the linac RF system. The RF power is divided to the gun and the accelerating section. Finally the time jitter between the pump-electron-beam and the probe-laser is designed to be 320 fs (rms). By using the new drive laser system, the charge of 7 nC per bunch was observed at the exit of the gun. Improvement of the vacuum in the gun < 10^{-9} Torr) is most effective to obtain such a high charge beam. After two and a half years operation of the gun, no degradation of QE has been found for the Cu photo-cathode. Show more

DOI: 10.3233/JAE-2002-495

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 143-150, 2002

Authors: Takasago, Kazuya | Yada, Akira | Miura, Taisuke | Washio, Masakazu | Kannari, Fumihiko | Torizuka, Kenji | Endo, Akira

Article Type: Research Article

Abstract: Arbitrary shaping of a sub-milli joule femtosecond pulses has been demonstrated by manipulation of optical frequency phase components on the Fourier plane. The shaped pulses were pulse trains and picosecond square pulses for low emittance electron generation in a RF photocathode. Since the pulse shaping apparatus was placed between an oscillator and a pulse stretcher in order to avoid damage to the liquid crystal spatial light modulator, phase-only modulation was used for shaping to avoid damage …to optical elements in a regenerative amplifier. The phase modulation was designed by simulated annealing optimization method. Show more

DOI: 10.3233/JAE-2002-373

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 151-156, 2002

Authors: Kashiwagi, S. | Hama, Y. | Hara, S. | Ishikawa, H. | Kuroda, R. | Kobuki, T. | Oshima, T. | Sato, K. | Washio, M. | Yada, A. | Urakawa, J. | Hayano, H.

Article Type: Research Article

Abstract: At Waseda University, we have started a new research project named "High-Tech Research Center Project" which is supported by the Ministry of Education, Culture, Sports, Science and Technology. In this project, a laser photo-cathode rf-gun with 1.6 acceleration cells has been installed for production of low emittance and short bunched electron beam. The high quality electron beam is very powerful tool for the study on radiation physics, radiation chemistry, material science etc. Development of pulsed X-ray …generation by the inverse Compton scattering between high quality electron beam and laser pulse obtained from an all-solid-state Nd:YLF laser system will be started in 2001 fiscal year. The system will be applied to the pulse radiolysis experiments for the studies on radiation physics and chemistry. In this paper, we will describe the X-ray generation experiment at Waseda University. Show more

DOI: 10.3233/JAE-2002-388

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 157-162, 2002

Authors: Masuda, Kai | Kii, Toshiteru | Yamaguchi, Tomohiko | Toku, Hisayuki | Yoshikawa, Kiyoshi | Yamazaki, Tetsuo

Article Type: Research Article

Abstract: Aiming at production of high brightness electron beams with longer pulses than several μsec for applications to free electron lasers by use of an RF gun with a thermionic cathode, the adverse effect of back-streaming electrons onto the cathode surface were studied both experimentally and numerically. Temperature rises of the thermionic cathode surface due to the back-streaming electrons were observed directly by use of an infrared thermometer. From the measured temperature rises, powers of the …back-streaming electron beams were, then, evaluated by use of a 0-dimensional model taking into account heat transfer through thermal radiation and thermal contact to the gun body, and comparisons were made with numerical results by use of a 2-dimensional particle-in-cell simulation code we have developed. Both by the experimental evaluation and by the particle-in-cell simulation, the beam power onto the cathode surface was found to increase with the increasing RF input to the RF gun cavities, and reach a considerable power compared to the cathode heater power supply. Show more

DOI: 10.3233/JAE-2002-376

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 163-170, 2002

Authors: Hajima, Ryoichi | Nishimori, Nobuyuki | Nagai, Ryoji | Shizuma, Toshiyuki | Sawamura, Masaru | Kikuzawa, Nobuhiro | Minehara, Eisuke J.

Article Type: Research Article

Abstract: We present recent results and future plans of the JAERI free-electron laser driven by a superconducting linac. These are experimental results of high-power IR lasing, third harmonic lasing, design and construction of energy-recovery system, and future extension to shorter wavelength.

DOI: 10.3233/JAE-2002-375

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 171-175, 2002

Authors: Tanaka, Hirofumi | Pu, Yuehu | Kim, Tae Hyun | Makita, Yo | Tsukishima, Chihiro | Nakanishi, Tetsuya | Nakamura, Shiro

Article Type: Research Article

Abstract: A CW microtron with a 500~MHz RF cavity is proposed for industrial applications. The machine is of a racetrack type. The acceleration energy and the beam power of a prototype machine are 5 MeV and 30 kW, respectively. The RF cavity is a conventional normal-conducting 2-cell cavity with coupling slots. The injection energy is 80 keV, and a 500 MHz CW gun is used. The bending magnets are divided into two subsections to adjust the acceleration phases of …every turn. Beam tracking studies show that the longitudinal phase stable region is more than 20 degrees and the transverse beam stability can be obtained with fringe fields of the bending magnets and two QMs near the RF cavity. Show more

DOI: 10.3233/JAE-2002-380

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 177-184, 2002

Authors: Marquardt, Niels

Article Type: Research Article

Abstract: Electron storage rings have become very powerful sources of electromagnetic radiation covering a wide spectral range. In particular, the high-flux, long-wavelength infrared (IR) radiation from synchrotron light sources is increasingly used for spectroscopy in basic and applied research. Besides ordinary IR synchrotron radiation emitted from homogeneous magnetic dipole fields (i.e. dipole radiation DR), another high-brilliant source of IR radiation has been discovered recently, which is emitted by relativistic electrons traversing the inhomogeneous …edge fields of bending magnets (i.e. edge radiation ER). In this paper a comparison is made between the very different radiation characteristics of DR and ER. Plans for the construction of a high-brilliant IR beamline at the storage ring DELTA, dedicated to an investigation of ER and to its use as a sensitive tool for electron-beam diagnostics, are presented. Moreover, various experiments for ellipsometry, FT-IR micro-spectroscopy and photothermal IR radiometry, exploiting the well-focussed, broadband IR-photon flux of high intensities are discussed. Show more

DOI: 10.3233/JAE-2002-371

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 185-190, 2002

Authors: Watanabe, T. | Sugahara, J. | Yoshii, K. | Ueda, T. | Uesaka, M. | Yoshimatsu, T. | Kondo, Y. | Sugiyama, Y. | Sasaki, S. | Ishi, K. | Shibata, Y.

Article Type: Research Article

Abstract: Measurements of longitudinal bunch length of picosecond electron bunches have been performed by the femtosecond streak camera, the interferometer and the polychromator and their results were compared with one another. As regards the radiation, transition radiation and diffraction radiation were investigated through the diagnostics. As a result, the fine agreements between them within 200 fs were obtained and the reliability of the interferometer and the polychromator for the diagnostics of less than …picosecond electron bunch were verified. Furthermore, nondestructive diagnostics for subpicosecond bunches was performed utilizing coherent diffraction radiation (CDR) interferometry. Show more

DOI: 10.3233/JAE-2002-386

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 191-196, 2002

Authors: Bane, K.L.F. | Naito, T. | Okugi, T. | Qin, Q. | Urakawa, J.

Article Type: Research Article

Abstract: We present energy spread and bunch length measurements at the Accelerator Test Facility (ATF) at KEK, as functions of current, for different ring rf voltages, and with the beam both on and off the coupling resonance. We fit the on-coupling bunch shapes to those of an impedance model consisting of a resistor and an inductor connected in series. We find that the fits are reasonably good, but that the resulting impedance is unexpectedly large.

DOI: 10.3233/JAE-2002-389

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 197-202, 2002

Authors: Nakamura, Kei | Watanabe, Takahiro | Ueda, Toru | Yoshii, Koji | Uesaka, Mitsuru

Article Type: Research Article

Abstract: Numerical analysis and measurement of longitudinal bunch length of subpico- and picosecond electron beams by the fluctuation method has been carried out at the S-band twin linear accelerators at Nuclear Engineering Research Laboratory (NERL), University of Tokyo. The diagnostics method utilizes a statistical analysis of shot-noise-driven fluctuations in incoherent radiation. Measurements were performed on Cherenkov radiation emitted by ∼ 1.0 ps (FWHM), 20 MeV electron bunch. As a result, the fluctuation method …indicated 5 times longer than that by the streak camera. The discrepancy was caused by neglecting the influence of the transverse emittance. Then, the influence of the transverse profile upon the measurement was analyzed and discussed. Show more

DOI: 10.3233/JAE-2002-387

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 203-208, 2002

Authors: Drabik, A. | Drabik, W. | Rabinski, M.

Article Type: Research Article

Abstract: The thermal loading of thin metal foils used as extraction windows in high current electron accelerators is one of the most important processes which should be analysed during the design of such devices. Heat loads at metal surface are also of special interest in many other plasma applications. The distribution of heat loads at the surface of thin metal foil is evaluated from the energy absorption in the foil and forced cooling with air flow. Time dependence of temperature …distribution at the foil surface is calculated from the two-dimensional heat conduction equation. The simplified heat transient analysis is also given to determine the influence of scanning frequencies, electron beam size and shape ,shape of current impulses in scanning coils, energy loss in foil, the beam current and air cooling coefficient on time evolution of temperature for an arbitrary fixed point at the foil in first period of electron beam scanning. Show more

DOI: 10.3233/JAE-2002-372

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 209-213, 2002

Authors: Tomioka, Satoshi | Nisiyama, Shusuke | Enoto, Takeaki

Article Type: Research Article

Abstract: For the purpose of non-destructive measurement of the cross-sectional shape of an electron beam, we have studied a detection system that is composed of both a number of antennas and a current monitor. The antenna detects an electric field, and the current monitor detects an integral of beam currents. The signals acquired from these detectors are applied as the input of an inverse problem. We adopt the genetic algorithm to simulate the profile measurement as …an inverse problem analysis. The results showed that this detection system is partially effective, even though this system is an "ill-posed problem" (i.e. the number of input data parameters is less than the number of parameters to be estimated). We also found that the current monitor, which cannot acquire position-dependent information, is nevertheless useful to accelerate the convergence of sub-optimal beam profiles. Show more

DOI: 10.3233/JAE-2002-369

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 215-219, 2002

Authors: Fukasawa, Atsushi | Kobayashi, Tetsuya | Uesaka, Mitsuru | Urakawa, Junji | Higo, Toshiyasu | Akemoto, Mitsuo | Hayano, Hitoshi

Article Type: Research Article

Abstract: Compact inverse Compton scattering hard X-ray source based on the X-band linac is numerically designed. The theoretical scaling law for emittance vs. charge / RF frequency was confirmed by the numerical analysis. The 3.5 cell RF gun with the field strength at the cathode surface 140 MV/m can produce the 2.1 MeV, 240 pC electron bunch, although the energy spread, 8% only 10^{5} photons/shot in this system, we have proposed several schemes to …achieve 10^{11} photons/10ms based on state-of-the-art technologies. Show more

DOI: 10.3233/JAE-2002-496

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 221-226, 2002

Authors: Dobashi, K. | Fukuda, M. | Hirose, T. | Kamiya, Y. | Sakai, I. | Aoki, T. | Higurashi, A. | Oshima, T. | Washio, M. | Kurihara, Y. | Okugi, T. | Omori, T. | Urakawa, J.

Article Type: Research Article

Abstract: We performed an experiment of high brightness gamma(γ)-rays production through laser-electron(e^{-} ) collisions using an insertion device with a short focal length of laser optics. Number of generated γ-rays with the bunch length of 26 psec (r.m.s) was 0.92 × 10^5 /bunch, thus leading to brightness 2.5 × 10^{17} /(mm^2 · mrad^2 · 0.1% band-width · sec). Quantitative considerations on the basis of …numerical model permitted to elucidate how characteristics of ^{-} and laser beam influence collision mechanisms. Show more

DOI: 10.3233/JAE-2002-497

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 227-231, 2002

Authors: Kinoshita, Kenichi | Ohkubo, Takeru | Yoshii, Koji | Harano, Hideki | Uesaka, Mitsuru

Article Type: Research Article

Abstract: For ultrafast material analyses, we constructed the time-resolved X-ray diffraction system utilizing ultrashort X-rays from laser produced plasma generated by the 12TW-50fs laser at Nuclear Engineering Research Laboratory. Ultrafast transient changes in laser-irradiated GaAs crystals were observed as X-ray diffraction patterns. A subpeak appears in X-ray diffraction profiles and shifts its position gradually as time goes in the case of 1.3 mJ/mm^2 laser fluence. Experimental results were compared with numerical …analyses to infer the atomic arrangement during the transition. Show more

DOI: 10.3233/JAE-2002-385

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 233-236, 2002

Authors: van Rienen, Ursula | Glock, Hans-Walter | Hecht, Dirk | Rothemund, Karsten

Article Type: Research Article

Abstract: This paper presents results on the computation of Higher Order Modes (shortly HOMs) in the designs for the accelerating structures which have already been built in into the TESLA [1] Test Facility (TTF) or are presently being studied as final design for the TESLA collider. Depending on the complexity of the studied arrangement different computational strategies are followed: 1. the use of commercial software packages like MAFIA [2] or CST Microwave Studio (MWS) [2] on workstations, …and 2. a recently implemented tool for Coupled S-Parameter Calculation (CSC) which easily allows to calculate the scattering properties of rf-sections connected to each other with arbitrary topology or to determine eigenmodes of resonating structures. Show more

DOI: 10.3233/JAE-2002-374

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 237-242, 2002

Authors: Nisiyama, Shusuke | Tomioka, Satoshi | Enoto, Takeaki

Article Type: Research Article

Abstract: In this paper, a scattered field Finite-Difference Time-Domain (FD-TD) method is applied to wake-fields computation. In the ordinary FD-TD method or other methods based on the finite difference scheme, the trajectory of a traveling charged particle beam should be along the spatial grid. In the presented method, an arbitrary beam trajectory can be treated since the beam current is not placed on the spatial grid but is considered as an incident field source. Wake potentials of …a simple system with a slightly angled beam trajectory are calculated for a demonstration. Show more

DOI: 10.3233/JAE-2002-370

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 243-247, 2002

Authors: Krassilnikov, Mikhail | Novokhatski, Alexandre | Weiland, Thomas

Article Type: Research Article

Abstract: V-Code, based on the Ensemble Model [1], was elaborated as fast and efficient tool for the beam dynamics simulation. The Ensemble Model equations are derived from Vlasov equation and involve the second order moments of the distribution function. The structure of accelerators and the features of the Ensemble Model determine the choice of the object-oriented approach for the code elaboration. Such approach gives an essential advantage in further extension, as the code can be improved continuously …by introducing new element classes. The Ensemble Model is valid for any energy range and the V-Code can simulate the entire accelerator. The present beam line database has been developed for the TESLA Test Facility (TTF DESY) accelerator component description. The results of the beam dynamics on-line simulation for TTF injector are presented. Show more

DOI: 10.3233/JAE-2002-494

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 249-253, 2002

Authors: Kotaki, Hideyuki | Kando, Masaki | Hosokai, Tomonao | Kondo, Shuji | Masuda, Shinichi | Kanazawa, Shuhei | Yokoyama, Takashi | Matoba, Toru | Nakajima, Kazuhisa

Article Type: Research Article

Abstract: Laser wakefield acceleration (LWFA) experiment using 100TW laser is planned at JAERI-Kansai. High quality short pulse electron beams and the precise electron-laser synchronization are necessary to accelerate the electron beam by the laser. A microtron with a photocathode rf-gun was developed as a high quality electron injector. The quantum efficiency(QE) of the photocathode was measured to be 2 × 10^{-5} . Emittance and a pulse width of the electron beams were 6π mm-mrad and 10ps, …respectively. In order to produce a short pulse electron beam, and to synchronize between the electron beam and the laser pulse, the inverse free electron laser (IFEL) is planed. A gas jet was set up and a density of the gas was measured by Mach-Zehnder interferometer. In order to overcome a short acceleration length of the LWFA, the Z-pinch plasma waveguide has been developed for 1 GeV laser wakefield acceleration. Show more

DOI: 10.3233/JAE-2002-383

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 255-262, 2002

Authors: Koyama, Kazuyoshi | Hazama, Hisanao | Saito, Naoaki | Tanimoto, Mitsumori

Article Type: Research Article

Abstract: Self-focusing of the intense laser pulses as well as production of the well-collimated electron beams in the moderately underdense plasma of n_{e}/n_{c} ≥ 10% 7 ×10^{17} W/cm^{2} . Progresses of a relativistic self-focusing in the plasma of a gaussian density profile were observed by an ultra-fast optical probing. Even if the large gas-target of the quasi-uniform density was used, the self-focusing was terminated after traveling approximately 1.2 mm by …the abrupt transition of the propagation mode from the smooth channeling to the complex filamentation, which correlated with the emission of MeV-electron beams. High-energy electron beams have the power-law spectrum of E^{-3.5} reaching the maximum energy of 2 MeV. The maximum number of the electrons was (1.3 ± 0.6) × 10^{11} /sr/shot. Model calculations suggest that the most plausible mechanism of the production of high-energy electron beam in the moderately underdense plasma is that the phase of the electron oscillation in filaments of the laser beam randomly changes many times. Show more

DOI: 10.3233/JAE-2002-377

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 263-269, 2002

Authors: Hafz, Nasr A.M. | Hemker, R. | Zhidkov, A. | Okuda, H. | Ghaly, W. | Kinoshita, K. | Hosokai, T. | Yoshii, K. | Ueda, T. | Watanabe, T. | Uesaka, M.

Article Type: Research Article

Abstract: The generation of an ultrashort relativistic electron bunch from a strong laser-plasma interaction have been studied by particle-in-cell simulations and observed experimentally. The electron beam was generated from the plasma created by focusing 12 TW (tera watt) laser pulse at the edge of helium gas jet expanded into the vacuum from a pulsed supersonic nozzle. The laser pulse duration was 50~fs (femtosecond). In the interaction of 50 fs, 12 TW laser pulse with plasma of density …of 5 × 10^{19} cm^{-3} , the electron generation was observed in the simulation at the very beginning of the interaction region. The plasma electrons were gaining higher energies by the huge longitudinal electric fields (created by the laser pulse) as they move through the rest of the plasma following the laser pulse. In the experiment, the electron beam transverse profile and its total charge have been measured in the forward direction (the same direction of the laser pulse) by using imaging plate and Faraday-cup, respectively. Show more

DOI: 10.3233/JAE-2002-379

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 271-276, 2002

Authors: Namba, Shinichi | Kawachi, Tetsuya | Hasegawa, Noboru | Nagashima, Keisuke | Sukegawa, Kouta | Kado, Masataka | Tanaka, Momoko | Daido, Hiroyuki | Kato, Yoshiaki

Article Type: Research Article

Abstract: High-density nitrogen gas was irradiated with an ultrashort high-intensity pulse laser (pulse width: 1.5 ps, intensity: ≥ 10^{15} W/cm^{2} ). It was found that highly charged ions were produced effectively as the gas density became higher. From distribution of population densities of high-lying levels of lithium like nitrogen ions, the electron temperature in a recombining phase was estimated. This electron temperature together with a calculation using a collisional-radiative model, …in which doubly excited levels of beryllium like ions are included, indicated that the electron density was n_{e} = 3 × 10^{19} cm^{-3} . Moreover, the spectra also showed that population inversions between some excited states of hydrogen-, helium-, lithium like nitrogen ions were generated under this plasma conditions. Show more

DOI: 10.3233/JAE-2002-384

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 277-282, 2002

Authors: Ito, Kiyokazu | Ogata, Atsushi | Okamoto, Hiromi

Article Type: Research Article

Abstract: We describe a possible accelerator system to provide an ion beam of extremely low emittance and low current. It is possible to reduce the beam size down to nanometer order keeping the beam divergence of microradian order. It can be used as a nano beam source for single ion implantation onto semiconductors and for the systematic study of radiation damage in bio-molecules and semiconductors. The whole system basically has a radio-frequency quadrupole configuration with a Paul …ion trap as injector. Ions are confined and cooled in the trap section, and then accelerated to ∼ MeV through an RFQ linac. Design speculation is made assuming acceleration of ^7 Li^+ ions. Show more

DOI: 10.3233/JAE-2002-378

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 283-287, 2002

Authors: Nakamura, S. | Morita, A. | Iwashita, Y. | Shirai, T. | Noda, A. | Daido, H. | Kato, Y.

Article Type: Research Article

Abstract: A phase rotation scheme is investigated for the ion beam that is emitted from foil target irradiated by a high power (100 TW) short-pulse (20 fs) laser. By application of an RF electric field synchronized with the laser pulse, the ion beams in the energy range of ± 5% our goal. Assumed parameters are 144 MHz for RF frequency and 280 kV RF amplitude for C^{6+} with center energy of 2 MeV/u using ± …π/4 RF phase range. We think that a quarter wave resonator with double-gaps is a good candidate for the RF-cavity. The gap length is 2 cm. Show more

DOI: 10.3233/JAE-2002-382

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 289-294, 2002

Authors: Rizawa, Takahito | Tamura, Hitoshi | Sato, Kenji

Article Type: Research Article

Abstract: A new concept of a tuning free cavity for an ion synchrotron is described, which is based on an idea of applying an all-pass network to a ferrite LC resonator. Though the new type cavity has a smaller and simpler structure than bias-tuned one, it can produce comparably high RF voltage and a wide frequency range. After high power tests of newly developed ferrite materials and a proto-type cavity proved the concept practicable, beam acceleration tests …were performed at HIMAC successfully. The course of developing the cavity is described with its unique merits and further applicability. Show more

DOI: 10.3233/JAE-2002-517

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 295-300, 2002

Authors: Fadil, H. | Shirai, T. | Iwashita, Y. | Noda, A. | Noda, K. | Beutelspacher, M.

Article Type: Research Article

Abstract: We investigate a scheme for electron cooling of ion beams with large momentum spread of ± (1%) accelerator (IndAcc) is utilized to accelerate or decelerate the stored ion beam in order to shift its momentum distribution toward the sensitive region of the electron cooling force. This method will be applied for further cooling of phase rotated hot ion beams produced by a high-power short pulse laser, to be used as an injection beam for synchrotron. Also, …an induction accelerator has been designed for construction at the HIMAC ring, which will be used to test the feasibility of the present sweep scheme experimentally. Show more

DOI: 10.3233/JAE-2002-381

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 301-306, 2002

Authors: Harano, Hideki | Ito, Chikara | Watanabe, Kenichi | Iguchi, Tetsuo

Article Type: Research Article

Abstract: A series of experiments has been examined the applicability of RIMS to the trace xenon isotopic analysis needed for the tagging gas FFDL. The measurement of the JOYO cover gas equivalent clarified the existence of non-resonantly produced argon ions which could disturb the trace analysis. We proposed to apply the mass gating and solved the problem, which enabled us to succeed in demonstrating that RIMS satisfies the requirement for the FFDL at the MONJU.

DOI: 10.3233/JAE-2002-367

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 307-310, 2002

Authors: Tanimoto, Yoshifumi | Izumi, Syunsuke | Furuta, Koichi | Suzuki, Tomoe | Fujiwara, Yoshihisa | Fujiwara, Masao | Hirata, Toshifumi | Yamada, Sotoshi

Article Type: Research Article

Abstract: The effects of high magnetic field on Euglena gracilis Z were examined. When a horizontal magnetic field gradient (ca. 400 T^2 m^{-1} ) was applied, living E. gracilis moved to a higher field (positive magnetotaxis), whereas dead one gathered in a lower field. Magnetotaxis was not observed in a uniform magnetic field of 8 T. E. gracilis was oriented almost perpendicularly to the magnetic field regardless of life and death. Magnetotaxis of E. gracilis …would be explained by taking into account inhomogeneous magnetic forces on and magnetic orientation of E. gracilis. Show more

DOI: 10.3233/JAE-2002-401

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 311-316, 2002

Authors: Sakamoto, Naoya | Ohashi, Toshiro | Sato, Masaaki

Article Type: Research Article

Abstract: The effect of magnetic field on nitric oxide (NO) production of cultured human umbilical vein endothelial cells (HUVECs) was investigated. Static magnetic fields (30 mT, 300 mT) and an oscillating magnetic field (30 mT, 20 Hz) were applied to HUVECs for 0.5, 1 and 6 hours and intracellular NO was observed using a fluorescent indicator. There was no effect of the static magnetic field on the NO production of the HUVECs. In contrast, the NO production …increased with applying the oscillating magnetic field for 0.5 hour. However, such an increase of NO production was not observed for 1 and 6 hours. We performed a separate experiment to clarify the mechanism of NO synthesis by using an inhibitor of calcium-independent activation of NO synthase. The inhibitor suppressed the increase of NO production caused by the oscillating magnetic field. It can be concluded that oscillating magnetic field may activate calcium-independent pathway of activation for NO synthase. Show more

DOI: 10.3233/JAE-2002-403

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 317-322, 2002

Authors: Miyakawa, Tomokazu | Harada, Shin-ichi | Ishimori, Takayuki | Yamamoto, Hiroshi | Hosono, Ryuji | Yamada, Sotoshi

Article Type: Research Article

Abstract: Responses of the small heat shock protein gene, hsp-16, were examined in transgenic Caenorhabditis elegans exposed to extremly low frequency magnetic fields (ELFMFs). Expression of the hsp-16-lacZ gene was enhanced when transgenic animals were exposed to magnetic fields up to 0.5 T at 60 Hz. The hsp-16 promoter was more efficiently expressed at the embryonic than at the post-embryonic stage irrespective of exposure. Promoter activity was more sensitive to the stimulus in the intestine at the …post-embryonic stage. Evidence is presented that the induction occurs at the transcriptional step of hsp-16. Show more

DOI: 10.3233/JAE-2002-405

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 323-326, 2002

Authors: Iwasaka, M. | Ueno, S. | Shiokawa, K.

Article Type: Research Article

Abstract: In the present study, a possible influence of intense magnetic fields on cleavage patterns during the early embryonic development of frogs was studied. The early cleavages in Xenopus laevis were disordered by horizontal magnetic fields of 10 T order. However, the magnetic field effect did not remain until when they become tadpoles.

DOI: 10.3233/JAE-2002-412

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 327-330, 2002

Authors: Nafalski, Andrew | Roy, Nirmal | Göl, Özdemir

Article Type: Research Article

Abstract: Modelling and prediction of magnetic fields in the vicinity of electrical power lines is an important contribution of electrical engineering to the clarification of uncertainty of the effects of low intensity magnetic fields on the living environment. The paper reports on investigations that use neural networks for the prediction of magnetic fields from power lines. Additional consideration is given to the lateral profile of magnetic fields as a result of asymmetry of the load in transmission …and distribution lines. Results of both assessments can be used in epidemiological and other studies. Show more

DOI: 10.3233/JAE-2002-407

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 331-335, 2002

Authors: Kanda, Hiroyuki | Watanabe, Masami | Fujikado, Takashi | Yagi, Tohru

Article Type: Research Article

Abstract: In a visual prosthesis, the visual nervous system of blind people are stimulated electrically in order to reconstruct their sense of sight. However electrical power supply to an internal device is limited. Therefore, it is very important to study efficient electrical stimulation. In our study, various pulse types were applied to the lateral geniculate nucleus (LGN) to record the neural responses from the visual cortex (V1) of cats. Experimental results revealed that the inversion of polarity …of electric current pulse was effective in electrical stimulation to the LGN. Show more

DOI: 10.3233/JAE-2002-410

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 337-340, 2002

Authors: Huang, Shiann-fong | Iramina, Keiji | Yumoto, Masato | Ueno, Shoogo

Article Type: Research Article

Abstract: In this study, we are interested in the endogenous negativity of the earlier negative component (designated NA) for observing some aspects of cognitive processes. We recorded the visual NA magnetic field with a 204-channel whole-scalp SQUID gradiometer and estimated the equivalent current dipoles (ECD) to clarify the source localization of NA. Visual evoked magnetic fields (EMFs) were recorded during a simple response task (SRT) and a discriminative response task (DRT) to examine the endogenous negative …component, NA. The characters of the NA curves for all subjects were the same [1]. The ECD sources for one subject were localized in the parietal section of the brain. Our data suggest the possibility of visual NA research in evoked magnetic fields. Show more

DOI: 10.3233/JAE-2002-409

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 341-346, 2002

Authors: Ito, Yuichiro | Yagi, Tohru | Ohnishi, Yasushi | Kiuchi, Kazutoshi | Uchikawa, Yoshiki

Article Type: Research Article

Abstract: The purpose of this study is to develop an implantable micro-electrode array, which is made of the conductive polymer, polypyrrole (PPy). For that purpose, we tried to fabricate micro-patterns of PPy using the photochemical reaction of oxidative polymerization agents. Moreover, the conductivity of the micro-pattern was evaluated in terms of pattern width, length and polymerization time. Experimental results showed that we could fabricate the micro-patterns, which had a line width of 3 …μm. This size was small enough for the purpose mentioned above. In addition, the conductivities of the micro-patterns were proportional to their width and length, and could be improved by suitable polymerization time. These results showed that the micro-patterns seemed to be applicable to a neural stimulating electrode. Show more

DOI: 10.3233/JAE-2002-498

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 347-352, 2002

Authors: Funase, Arao | Yagi, Tohru | Barros, Allan K. | Kuno, Yoshiaki | Uchikawa, Yoshiki

Article Type: Research Article

Abstract: The purpose of our study is to analyze the relationship between the fast eye movements, i.e., "saccade", and the electroencephalogram (EEG). The recorded EEG during saccade was analyzed with the independent component analysis (ICA) method. During visually guided saccade experiments, we observed a sharp change of the ICA signals more frequently immediately before eye movement than at other peak point of reference signals, while this was not the case under the condition of no eye movement. …These results indicate that the phenomenon of signal change is possibly related to the motion processing of saccade, or to the attention to the visual stimulus. Show more

DOI: 10.3233/JAE-2002-518

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 353-358, 2002

Authors: Starzyński, Jacek | Sawicki, Bartosz | Wincenciak, Stanisław | Krawczyk, Andrzej | Zyss, Tomasz

Article Type: Research Article

Abstract: The paper attempts to create a mathematical model of the transcranial magnetic stimulation (TMS), the technique that aims at replacing the electro-convulsive treatment (ECT) in the therapy of deep depression. The magnetic field calculation is based on the T-Ω formulation, which, due to low electric conductivity and constant magnetic permeability of the brain tissue, allows us to build finite element model of the head only.

DOI: 10.3233/JAE-2002-413

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 359-364, 2002

Authors: Golovanov, Carmen | Urma, Daniela | Albu, Mihaela | Ioan, D.

Article Type: Research Article

Abstract: Transmission and distribution lines together with the power transformers produce electromagnetic fields that represent a subject for many controversial issues. A special problem is to evaluate the electric field induced in a human body, when this is exposed to low-frequency magnetic field. In this paper, a 3D human body model is proposed in order to determine the current densities induced by a 50~Hz magnetic field.

DOI: 10.3233/JAE-2002-406

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 365-368, 2002

Authors: Liu, Mai | Uchikawa, Yoshinori

Article Type: Research Article

Abstract: A wavelet transform based band pass filters were used to analyze the QRS complex in a three-dimensional magnetocardiogram (3-D MCG) recorded from normal subjects and a patient with anterior myocardial infarction (MI). The high frequency components of the QRS complex related to the ventricular late fields (LF) were detected from the patient with anterior MI at different scale. The weak magnetic signals were quantified by calculating root-mean-square (RMS) value at different scale. In order to discuss …the activities of the heart between the normal subject and the patient with anterior MI, the spatial energy distribution (SED) of the QRS complex was also evaluated by displaying isoenergy contour maps at different scale. Show more

DOI: 10.3233/JAE-2002-404

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 369-376, 2002

Authors: Čápová, Klára | Blazek, Vladimír | Čáp, Ivo | Bučkuliaková, Lýdia

Article Type: Research Article

Abstract: The paper deals with the modelling and the simulation of physiological fluid systems with the emphasis on the human vascular system. The presented simulation method has been developed as a helpful tool for the computer-aided non-invasive diagnostics of living bodies. Using the electromechanical analogy between physiological and electrical values the introduced method makes possible the description and 3D representation of the non-linear characteristics of the human haemodynamics as well. The simulation procedure …and the obtained results verified by the experiment enable to visualize all physiological and pathophysiological states of the human vascular system. Show more

DOI: 10.3233/JAE-2002-408

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 377-380, 2002

Authors: Tanaka, Mami | Sakamoto, Tetsushi | Wang, Feng | Namima, Takashige | Tanahashi, Yoshikatsu | Chonan, Seiji

Article Type: Research Article

Abstract: This paper presents the development of a mechanical SMA urethral valve driven by a portable transcutaneous energy transmission system, which is powered by batteries. Structure of the valve was improved by introducing a bite mechanism in order to prevent the pinch of urethra by the valve. The cycling characteristics and energy transmission efficiency were examined by laboratory tests. Experimental results show that the stable operation can be obtained by introducing a voltage regulating circuit to the …energy transmission system and utilizing the sinusoidal oscillation in the energy transmission system can enhance the transmission efficiency. Furthermore, the function of the valve system was tested by the in vitro and in vivo animal experiments. Show more

DOI: 10.3233/JAE-2002-402

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 381-390, 2002

Authors: Iwasaka, Masakazu | Ueno, Shoogo

Article Type: Research Article

Abstract: The diamagnetic torque energy of the smooth muscle cell, endothelial cell, and an extra-cellular matrix, such as collagen, which form blood vessel, exhibited a conformational change in cells under static magnetic fields of up to 14 T. As a tool to develop new medical applications of strong magnetic fields, the magnetic manipulations of cells by diamagnetic energy were discussed.

DOI: 10.3233/JAE-2002-411

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 391-396, 2002

Authors: Tanaka, Mami | Hiraizumi, Jun | Lévêque, Jean Luc | Chonan, Seiji

Article Type: Research Article

Abstract: The present paper is concerned with the development of a haptic sensor that evaluates the human skin conditions. The base of the sensor is an aluminum shell, around which a rubber sponge layer, PVDF film, a protective layer of acetate film and gauze are stacked in sequence. The sensor is attached on to the tip of an elastic cantilevered beam and pressed against an the surface of the skin. It is then slid over the skin to collect the surface …morphological features. Characteristics of data are examined by calculating the variance and the power intensity ration over several segmented frequency ranges. The sensor is applied to seeing the variation of skin conditions depending on ages. Show more

DOI: 10.3233/JAE-2002-415

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 397-404, 2002

Authors: Cherechukin, A.A. | Dikshtein, I.E. | Ermakov, D.I. | Glebov, A.V. | Koledov, V.V. | Shavrov, V.G. | Takagi, T. | Tulaikova, A.A.

Article Type: Research Article

Abstract: A reversible field-induced structural phase transition in shape-memory ferromagnetic alloys Ni_{2+x} Mn_{1-x} Ga has been observed at fixed temperature and pressure in magnetic fields about 100 kOe. The theoretical results are in qualitative agreement with experiment.

DOI: 10.3233/JAE-2002-421

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 405-410, 2002

Authors: Luo, Yun | Takagi, Toshiyuki | Matsuzawa, Kenichi

Article Type: Research Article

Abstract: An artificial sphincter using shape memory alloys (SMAs) has already been proposed by the authors [1]. Thermomechanical properties of the artificial sphincter have been evaluated experimentally. The main work of the present paper is to conduct numerical computation using finite element method (FEM) to simulate the thermomechanical behavior of SMA plates used in artificial sphincters, and to investigate the relation between the applied power and thermomechanical responses, for the design purpose.

DOI: 10.3233/JAE-2002-423

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 411-416, 2002

Authors: dell'Isola, Francesco | Henneke, Edmund G. | Porfiri, Maurizio

Article Type: Research Article

Abstract: This paper proves that it is possible to damp mechanical vibrations of some beam frames by means of piezoelectric actuators interconnected via passive networks. We create a kind of electromechanical wave guide where the electrical velocity group equals the mechanical one thus enabling an electromechanical energy transfer. Numerical simulations are presented which prove the technical feasibility of the proposed device.

DOI: 10.3233/JAE-2002-501

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 417-424, 2002

Authors: Komagome, Yuji | Matsumoto, Eiji

Article Type: Research Article

Abstract: The surface strain distribution of a plate can be measured from the electric potential on the piezoelectric film mounted on it. When the plate with a back surface defect is deformed, the resultant strain distribution on the front surface reflects the size and the shape of the defect. Instead of measuring the electric potential by the electrostatic voltmeter, this paper attempts to visualize the strain distribution by means of absorption of charged polymer powder to the …piezoelectric film. And also attempting this method to the various size of the defect, resolution of detecting the defects is discussed by the experiment. Show more

DOI: 10.3233/JAE-2002-418

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 425-428, 2002

Authors: Nowacki, J.P. | Alshits, V.I. | Radowicz, A.

Article Type: Research Article

Abstract: The 2D electro-elastic fields in the piezoelectric layer-substrate structure with the general line defect are found. The considered line source consists of the four coinciding straight sources: the line of forces, the charged line, the dislocation line and its electrostatic analogue. Electrically, the surface of the layer is supposed to be either metallized or adjoined to an isotropic dielectric medium. Mechanically, two boundary problems are also considered: the surface is free, and the surface is clamped. …The solutions obtained for a general case of unrestricted anisotropy are presented in a form of convergent Fourier integrals. The integrands are implicitly expressed in terms of the eigenvalues and the eigenvectors of the generalized Stroh matrix. Their finding needs additional computing. Show more

DOI: 10.3233/JAE-2002-416

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 429-433, 2002

Authors: Wakiwaka, Hiroyuki | Yamada, Yoji | Watanabe, Toshihiko | Umemoto, Yoshiyuki | Kiyomiya, Teruo | Makimura, Mika

Article Type: Research Article

Abstract: Giant magnetostrictive thin films are suitable to develop new micro-sensors and micro-actuators due to their superior characteristics. In this paper, the influence on magnetostriction characteristic of magnetron sputtered film by sputtering condition is described. The thin film shows large magnetostriction in Tb composition 40 at %, in anneal temperature 300°C.

DOI: 10.3233/JAE-2002-419

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 435-438, 2002

Authors: Tufescu, Florin Mihai | Chiriac, Horia | Óvári, Tibor-Adrian | Stancu, Alexandru

Article Type: Research Article

Abstract: Results on the FMR investigation of the effect of applied tensile stresses on the surface magnetic anisotropy of Co6_{8.25} Fe_{4.5} Si_{12.25} B_{15} amorphous glass-covered wires are reported. Axially applied stresses lead to a decrease of the resonance field and absorption intensity that correspond to the main resonance peak, indicating a reinforcement of the circumferential magnetoelastic anisotropy from the wire's surface region. The FMR spectra determined at 8.5 GHz …-- the lowest employed frequency of the microwave field -- display a compound aspect, i.e. a secondary resonance peak is observed at slightly larger values of the dc magnetic field. This fact indicates that one can detect a region with different anisotropy direction towards the wire's inner zone when the magnetic penetration depth is large enough. The obtained results are valuable as regards the sensor applications of such materials. Show more

DOI: 10.3233/JAE-2002-420

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 439-442, 2002

Authors: Tachibana, Toshihide | Kikura, Hiroshige | Matsuzaki, Mitsuo | Yamanaka, Gentaro | Aritomi, Masanori | Kobayashi, Yuji | Nakatani, Isao

Article Type: Research Article

Abstract: Thermal behavior and cluster formation of ferromagnetic particles in the water-based, kerosene-based and alkyl-naphthalene-based magnetic fluids were investigated using an optical microscope system. Real-time visualization of the Brownian motion and the chain-like cluster formation of three types of particles were carried out under a magnetic field. The influence of the magnetic field intensity and the temperature variation on cluster formation of ferromagnetic particles was investigated.

DOI: 10.3233/JAE-2002-422

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 443-446, 2002

Authors: Yamane, Ryuichiro | Togashi, Kazuo | Chinone, Yasuhiro | Park, Myeong-Kwan

Article Type: Research Article

Abstract: Method to induce and control the flow of the magnetic fluid using a double-decked linear motor is proposed and tested. The upper coil of the linear motor generates the basic traveling magnetic field, and the lower one the second harmonics. When the electric current is supplied to only one of the upper and the lower coils, the induced velocity of the magnetic fluid increases with the increase in the strength and the frequency of the applied electric …current. When applied simultaneously to the same or opposite direction, the induced velocity is approximated by the square root of the sum or the difference of the square of each velocity at independently applied electric current, respectively. Show more

DOI: 10.3233/JAE-2002-499

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 447-450, 2002

Authors: Sudo, S. | Ise, K. | Nishiyama, H. | Tani, J.

Article Type: Research Article

Abstract: The results of an experimental study of frequency characteristics of a permanent magnet-magnetic fluid element on a vertically vibrated table were presented and discussed in some detail. Some effects of excitation frequency on the motion of the magnet-magnetic fluid element were noted. The dynamic behavior of magnetic fluid surface was also revealed by two high speed digital cameras.

DOI: 10.3233/JAE-2002-414

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 451-454, 2002

Authors: Shimada, Kunio | Syuchi, Narimitsu | Kamiyama, Shinichi | Yamaguchi, Hiroshi

Article Type: Research Article

Abstract: Numerical analysis of a steady magnetic fluid flow in a straight pipe is made by taking into account nonuniform distribution of mass concentration and formation of prorate spheroids of magnetic particles under a steady nonuniform magnetic field. The local shear rate, number of aggregated particles as a prorate spheroid and fluid velocity distribution are obtained to be clarify that their large change exists at the down stream area of the magnetic field. The relation of wall …friction to Reynolds number shows good agreement with the experimental data. Show more

DOI: 10.3233/JAE-2002-417

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 455-458, 2002

Authors: Li, B.Q. | He, R.

Article Type: Research Article

Abstract: This paper discusses the numerical modeling of coupled electromagnetic and transport (fluid flow and heat and mass transfer) phenomena in materials processing systems under both terrestrial and microgravity conditions. Two types of magnetically induced transport phenomena are considered and both require iterative numerical computations. For the former, the flow is activated through Faraday's law and the computational methodology entails the use of the boundary element method to model the free space region …and of the finite element method to model the interior region of the liquid. Computations involve the iterative solution of magnetic fields, fluid flow and surface stress balance when free surface deformation occurs. For the later, the fluid motion is suppressed by an applied DC magnetic field and flow and magnetic fields are coupled so that iterative computational procedure is again required. For this later case, computational costs are substantially reduced by carefully designing the finite element global matrix structure. Show more

DOI: 10.3233/JAE-2002-500

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 459-466, 2002

Authors: Shoji, Tetsuo | Sato, Yasumoto | Minkov, Dorian | Yagi, Kenichi | Baba, Toshimitsu | Tamakawa, Kinji

Article Type: Research Article

Abstract: The objective of the Center of Excellence (COE) program is to provide a fundamental understanding of the physics and chemistry of fracture under combined environments and to apply this understanding to establish structural life prediction and control systems for high quality human safety. With this aim, we have developed analytical methods for the local measurement of materials chemistry, crack tip water chemistry, crack tip strain and defects. We summarize the research activity of COE program and …some recent progress using the electromagnetic NDE technique will be reviewed. Show more

DOI: 10.3233/JAE-2002-521

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 467-476, 2002

Authors: Reis, D. Dos | Lambert, M. | Lesselier, D.

Article Type: Research Article

Abstract: Diffusive fields in 3-D configurations, e.g., as those faced when searching for inclusions in conductive planar layered media (a metal slab, a half-space subsoil) at low frequencies, can be modeled via Green's integral formulations that require Green dyads. Such formulations make good use of extended Born approximations in order to express the secondary sources existing within the probed inclusion from the primary fields at same location. Here it is sketched how several such approximations perform in …cases of interest by comparison with full solutions and benchmark measurements. Show more

DOI: 10.3233/JAE-2002-424

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 477-481, 2002

Authors: Pávó, József

Article Type: Research Article

Abstract: A forward calculation method is presented for the analysis of the interaction of a pancake type eddy current testing (ECT) coil and an arbitrary shape thin metal deposit located on the reverse side of a plate specimen. The deposit is modelled as an infinitesimally thin layer where the impedance type boundary conditions are enforced. The given boundary conditions result an integral equation which solution provides the actual distribution of secondary sources modelling the presence of the …deposit. Knowing these secondary sources, the signal of the ECT probe is calculated. Based on the developed forward solution, a proposal for a method reconstructing the shape of the deposit from measured ECT signal is outlined. Show more

DOI: 10.3233/JAE-2002-431

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 483-488, 2002

Authors: Morabito, F.C. | Calcagno, S. | Versaci, M.

Article Type: Research Article

Abstract: Eddy current techniques (ECT) for Nondestructive Testing and Evaluation (NDT/NDE) of conducting materials is one of the most application-oriented field of research within electromagnetics. In this work, a fuzzy approach is proposed to estimate the presence of holes in metallic plates starting from a set of experimental eddy current measurements, carried out at the NDT Lab in Reggio Calabria. The above inverse problem is solved by means of a system that extracts information on the specimen …under test from the measurements and implements a priori constraints to facilitate the detection and characterization of the defect. The method utilizes the concepts of fuzzy inference in order to estimate the location of the defect from a reduced set of features. Show more

DOI: 10.3233/JAE-2002-435

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 489-494, 2002

Authors: Cheng, Weiying | Miya, Kenzo

Article Type: Research Article

Abstract: This paper presents a two-step algorithm to reconstruct parallel cracks from ECT (eddy current testing) signals. The number, the approximate locations and lengths of cracks are determined in the separation stage by employing the eddy current imaging, and the profiles of cracks are obtained in the reconstruction stage.

DOI: 10.3233/JAE-2002-436

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 495-502, 2002

Authors: Taniguchi, T. | Nakamura, K. | Yamada, S. | Iwahara, M.

Article Type: Research Article

Abstract: This paper presents an image processing method for eddy-current testing for the detection of the defects with a specific orientation. The method utilizes the fact that a line-shaped signal is, throught the Fourier transform, mapped onto a line passing through the origin and perpendicular to the orientation of the original signal. Hence, nonseparable fan filters is used to select the frequency components corresponding to the defects orientated in a specific direction. This approach enables more precise …control of the extraction characteristics of signals compared to the iterative application of one-dimensional (1-D) filtering in the vertical and horizontal directions, in which the shape of the pass band is restricted to a geometry made from squares. The effectiveness of the proposed method is shown by a demonstration using a metallic sample with a defect aligned in a number of directions. Show more

DOI: 10.3233/JAE-2002-520

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 503-506, 2002

Authors: Albanese, Raffaele | Rubinacci, Guglielmo | Tamburrino, Antonello | Villone, Fabio

Article Type: Research Article

Abstract: The paper presents the main features of a numerical model for the reconstruction of current sources, on the basis of the knowledge of a set of magnetic measurements. The problem, one of the key issues in biomagnetics research, is solved by extending a method developed in the frame of NDE, for the detection of volume cracks.

DOI: 10.3233/JAE-2002-434

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 507-512, 2002

Authors: Chen, Zhenmao | Preda, Gabriel | Mihalache, Ovidiu | Miya, Kenzo

Article Type: Research Article

Abstract: In this paper, a rapid forward scheme is proposed for simulation of the static magnetic flux leakage (MFL) signals arisen from an object of ferromagnetic material. By storing precalculated distribution data of the unflawed magnetic field into a database, the analysis region for solving the field perturbation due to a crack is greatly reduced by applying the feature that only the magnetic field in the vicinity of a crack can be significantly perturbed due to the …presence of a crack. Having implemented the new scheme into an FEM-BEM hybrid code of the polarization method, the validity of the proposed method is proved by comparing numerical results of the fast forward solver with those obtained by the FEM-BEM polarization code. Show more

DOI: 10.3233/JAE-2002-426

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 14, no. 1-4, pp. 513-520, 2002