We consider selective reflection of electromagnetic fields based on the biomechanism called structural coloration. The selective reflection mechanism proposed in this paper has the property that only electromagnetic fields with specified frequencies are reflected and those with other frequencies are transmitted. We show that the proposed mechanism can selectively reflect electromagnetic fields with specified frequencies near 1 GHz.

抄録全体を表示

The purpose of the present study is to evaluate the physiological effects of pulsed magnetic stimulation of the brain in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. We observed and compared changes in heart rate, arterial blood pressure, the coefficient of variation, and two frequency components reflecting cardiac sympathetic and parasympathetic activities and vasomotor sympathetic tone from autoregressive (AR) power spectra of pulse interval (PIV) and systolic blood pressure variabilities (SPV) in three periods, i. e. control, pulsed magnetic stimulation-response, and recovery. We also calculated the baroreflex sensitivity (BRS) from spontaneous changes in blood pressure and pulse interval. In our results, SHR showed a decrease in arterial blood pressure and sympathetic activity compared with those in the control group, but no changes in WKY rats. Our conclusion is that pulsed magnetic stimulation may be used as an effective control tool for essential hypertension.

抄録全体を表示

A time series reflecting human brain activities was detected by using a sensitive micro-acceleration · inclined-angle sensor composed of a CoSiB magnetostrictive amorphous wire connected to a CMOS IC circuit with a resolution of about 0.1 Gal and 0.2°. A small sensor head using a glass specimen of 0.16 mm thick, 3 mm wide, and 15 mm long to which were attached a CoSiB amorphous wire of 20 μm diameter and 5 mm length and an inertia mass of 0.1 g was fixed to the center of a subject’s forehead.
The detected waveforms of the sensor output for subjects with both eyelids closed differ from the microvibration would be classified into the following four kinds of states:
(1) An almost flat waveform indicates that the subject is in a resting state or a sleeping state.
(2) Passively stressful states such as recalling sad memories, being obliged to perform an unpleasant task, or performing a mental calculation generate a large stepwise wave with some irregular pulsing waves.
(3) Actively stressful states such as finding a good idea and focusing on inventing something are indicated by high-frequency pulsing waves.
(4) Pleasant states such as recalling happy memories of childhood or thinking about a favorite hobby are indicated by rhythmical waves without pulses.
These signals reflecting a subject’s mental and emotional states (which we call a mechano-encephalogram) are considered to be due to micro-deformation and acceleration of the measurement position with some movement of eyeball muscles, arrector pili muscles and muscles corrugator supercilii. Microvibrations of small amplitude were also detected.

抄録全体を表示

High-temperature hyperthermia is proposed as a means of reliably necrotizing malignant tumors in cancer therapy. Consideration of the temperature distributions of two kinds of hybrid heaters showed that a hybrid heater with two metal rings attached is superior to a hybrid heater with one metal ring attached.

抄録全体を表示

Hyperthermia is a therapy for cancer. The soft heating method is a kind of inductive heating method that uses thermosensitive magnetic material with a short circuit ring as a heating element. The heating sources are hysteresis loss and eddy current loss generated in a high-frequency alternating magnetic field. This study discusses handy excitation coils for the soft heating method on the basis of simulation.

抄録全体を表示

We carried out a 3D vector measurement of magneto-cardiograms (MCGs) of normal subjects and a patient with a right bundle branch block (RBBB), using a 3D second-order gradiometer connected to 39-channel SQUIDs, which can detect the magnetic field components perpendicular to the chest wall (Bz) and tangential to the chest wall (Bx,By) simultaneously. In order to compare the propagation pathway of the excitation in the heart for normal subjects and a patient with RBBB, a source estimation to the QRS complex was performed using the single-equivalent-current-dipole (ECD) method. It was found that, in both the normal subjects and the patient with RBBB, the ECD traced nearly the same pathway from the onset of the QRS complex to 50 ms (R-wave). But, for 60 to 150 ms, the trajectories of the ECD location in the patient with RBBB, which moved from the left to the right ventricle at a depth of about 4.5 to 7.5 cm from the body surface, clearly differed from those of the normal subjects, which stayed at the center of the heart. These differences were also confirmed by visual inspection of the movement of the extreme value of By in isofield contour maps.

抄録全体を表示

Wavelet packets (WPs) was applied to detect the high frequency components of the QRS complex in magnetocardiogram (MCG) signals recorded by a 3-D second-order gradiometer connected to three rf-SQUIDs. By using a quadrature mirror filter (QMF) bank in the WPs implementation, we performed the MCG waveform analysis for a normal subject and a patient with myocardial infarction (MI). The high frequency components of the QRS complex related to the ventricular late potential (LP) were observable from a patient with MI at different scale. By computing its root-mean-square (RMS), the ventricular LP extended a mean of about 40 ms after termination of the QRS complex. The amplitude had about 0.33 pT, 0.46 pT, 0.49 pT respectively for Bx, By, Bz components, the bandwidth was about from 625 to 125 Hz. It is useful to use the WPs for signal processing to 3-D MCG signals.

抄録全体を表示

The effect of ac electromagnetic fields (EMFs) was studied on the expression of the hsp-16-lacZ fusion gene in Caenorhabditis elegans. An alternating and a rotating EMFs at 60 Hz were compared under high-precision temperature control. The expression of the fusion gene was assessed by the extent of positive animals on lacZ after exposure to heat or heat-magnetic field stress. Expression of the fusion gene was enhanced when transgenic animals were exposed to an alternating EMF up to 0.5T. The expression was not detected in transgenic animals defective in the hsp promoter region. Thus, the enhancement of the fusion gene was dependent on the strength of the alternating EMFs. The significant induction of hsp-16 was also observed when animals was exposed to a rotating EMFs.

抄録全体を表示

We carried out a 3D vector measurement of magnetocardiograms (MCGs) of normal subjects and a patient with a right bundle branch block (RBBB), using a 3D second-order gradiometer connected to 39-channel SQUIDs, which can detect the magnetic field components perpendicular to the chest wall (Bz) and tangential to the chest wall (Bx, By) simultaneously. In order to compare the frequency distribution on the body surface between normal subjects and a patient with RBBB, a short-term spectrum of these MCG data was calculated by using an autoregressive (AR) model, and a time change in the power spectrum was analyzed (time-frequency analysis).

抄録全体を表示

There are no reported studies of the effects of magnetic fields on osteoblast collagen secretory processes during osteoblast differentiation. We hypothesized that a mixture of collagen and osteoblasts, an adherent cell, would orient perpendicular to a magnetic field, since collagen fibers are known to orient perpendicular to magnetic fields. We tested this hypothesis by comparing the magnetic orientation of osteoblasts and the magnetic orientation of an osteoblast and collagen mixture after long-term exposure to 8 T magnetic fields, which were produced by a superconducting magnet, or without exposure to magnetic fields (control). We observed that osteoblasts oriented parallel to the magnetic fields, but a mixture of osteoblasts and collagen oriented perpendicular to the magnetic fields. The magnetic control of osteoblast orientation will help the developement of potential medical and engineering applications.

抄録全体を表示

A large increase in the efficiency of a step motor for driving the hands of a wristwatch is reported Two main methods are used: strengthening the magnetic combination of a rotor magnet and a one-piece stator by narrowing the gap between them, and adjusting the detent torque by introducing a new structure that reduces the thickness of the rotor hole part of the stator, which generates the detent torque.

抄録全体を表示

Basic swimming properties of a bending-type in-pipe micro-machine were investigated. The micro-machine consists of a permanent magnet attached to an elastic plate, and can be remotely driven by an external alternating magnetic field. The swimming velocity depends on the excitation conditions and the shape of the elastic plate. First, we examined the frequency dependence of the swimming velocity and found that two peaks occurred due to the mechanical resonance and a lack of the power required for swimming. Next, we examined the effect of the shape of the elastic plate, and found that the shape suitable for higher velocity changed markedly according to the intensity of the magnetic field.

抄録全体を表示

A multispeed, single-plane magnetic gear can be designed compactly and used in a confined space. However, a magnetic connection occurs between the pinion and each gear train during meshing, and influences the performance characteristics.
Performance characteristics testing of magnetic gears with various teeth profiles was carried out to eliminate undesirable magnetic connections and increase the gears ’ load-carrying capacity.
As a result, a desirable gear pair with good performance characteristics was developed. A new mechanism for magnetic planetary and differential gearing was obtained, in which the gear trains are separated to allow free rotation.

抄録全体を表示

Mechanical technology makes wide use of the separation and transfer of non-magnetic materials in various production manufacturing processes. This paper describes the fundamentals of projection, separation, and transfer of aluminum sheets as non-magnetic materials (for example aluminum disc), using a magnetic repulsion force, by means of a solenoid-type electromagnetic launcher.
The key points of this paper are as follows:
(1) Linear projection of Al discs.
(2) Nonlinear projection of Al discs.
(3) Nonlinear guide projection of Al discs.

抄録全体を表示

Camcorders would be more compact, lighter, and lower-priced if their drive motors were built into their lens barrels. We propose a new direct-drive motor built into a lens barrel. The characteristics of motors with 10 rotor magnet poles reported in previous papers were studied. Analysis by the effects of the number of rotor magnet poles on characteristics of the motors is important for optimum design of these motors. The air-gap magnetic flux densities of ring magnets linked with armature windings are not increased or saturated even when the magnet pole angles are increased by more than 60 degrees (this means that there are fewer than 6 poles). On the other hand, position errors of motors with 8, 10 and 14 poles are smaller than motors with 2, 4 and 6 poles; hence, motors with more than 8 magnet poles are advantageous in position controls.

抄録全体を表示

The fundamental characteristics of transport and switching systems using X-Y linear induction motor (LIM) are reported with the aim of enabling the non-contact transport. Further, the switching of a carrier in which the position of the center of gravity shifts is investigated. We examine the cose in which the center of gravity does not exist at the center of the carrier and shift in the axial directions, but may exist at any position on the carrier. Switching characteristics for the existence of the center of gravity at any position can know from the ratio of the length and width of the carrier, and fundamental switching characteristics of the carrier.

抄録全体を表示

An X-Y linear induction motor (X-Y LIM) is a structure having two windings in the horizontal x^- and y^- axis directions. Exciting one winding generates a one-directional thrust, and a two-dimensional drive becomes possible by exciting two windings at the same time.
In this paper, we propose a suitable planning method based on the three-dimensional finite element method, whereby fundamental equations used in analysis are derived to extract one pole of an X-Y LIM. The following characteristics were examined to obtain guidelines for future designs: (1) magnetic flux density with respect to gap and slot depth, (2) magnetic flux density with respect to slot depth and tooth width, (3) starting thrust with respect to primary current and gap, and (4) relationship between the frequency and magnetic flux density.

抄録全体を表示

Recently, thin-type permanent magnet have been increasingly used to reduce the size of motors and actuators. However, the characteristics of a permanent magnet defetiorate when it is thinned. The demagnetization of a magnet leads to a design that miniaturized the motor and actuator. We developed a low power, thin linear oscillatory actuator (LOA) for cellular phones. A thin-type permanent magnet is used for the LOA. The characteristics of the LOA might be adversely affected by demagnetization of a thin-type permanent magnet. This paper describes (1) the structure and operating principle of the LOA for cellular phones, (2) considerations on the coercive force based on the thrust characteristics of the LOA, and (3) considerations of coercive force based on measurement of the magnetic flux density.

抄録全体を表示

In recent years, small moving-magnet-type linear actuators have gained widespread popularity in the field of office and factory automation. However, the thrust generation decreases when the linear actuator is small. This paper explains how to achieve high thrust in small slot type linear actuators. The finite element method was used to examine the thrust characteristics of a slot-type moving magnet linear actuator (SMLA). As the result, the thrust was able to be increased to 28 %. This paper : (1) compares the proposed actuator with previous types of linear actuator, (2) describes the thrust generation principle of the SMLA, (3) inves trgates how to achieve high thrust by the finite element method, (4) explains the influence of slot size on the thrust.

抄録全体を表示

The switched reluctance motor (SRM) exhibits various desirable features, including simple construction, high reliability, and low cost. However, it has not been widely used in practical applications because of its large torque ripple, noise, and low power factor. Furthermore, the optimum design has not been clarified. In this paper, we calculate fundamental equations for the characteristics of the SRM under a simple assumption. On the basis of these fundamental equations, we consider the relation between efficiency and loss.

抄録全体を表示

Electric vehicles are desirable because of environmental considerations. It is therefore important to develop high-performance motors suitable for use in electric vehicles. The switched reluctance motor (SRM) has simple construction, high reliability, and low cost. Furthermore, it has desirable features for electric vehicle motors. In this paper, we report the characteristics of a prototype SRM, and consider its application to electric vehicles. The driving force is examined on the basis of the calculation characteristics. We report the application of SRM to an electric vehicle.

抄録全体を表示

This paper describes the operating characteristics of a linear parametric motor with an open magnetic circuit. An iron plate was installed on the magnetic pole state in order to increase the thrust. As a result, the thrust increased by 26%. To optimize the design of the motor, the relation between the width of the magnetic core and the static thrust was examined. The static thrust increased when the width of the magnetic core was increased. As a result, it was possible to improve the thrust-to-input power ratio and the thrust-to-mass ratio.

抄録全体を表示

This paper describes the influence of the magnetic core width on the characteristic values of a linear parametric motor with double driving surfaces. The influence on the motor characteristics of increasing the magnetic core width is discussed As a result, it is clarified that the static thrust increases almost proportionally to the magnetic core width and the static thrust increases by 2.9 and 4.5 times when the size of the driving area is double and tripled, respectively. However, the magnetic core width has an appropriate value for the thrust-to-input ratio Fs/P₁ and thrust-to-mass ratio Fs/M.

抄録全体を表示

The swimming properties of a magnetic micro-machine with a spiral structure were examined experimentally and theoretically under very low Reynolds number conditions. It was demonstrated that the micro-machine could swim in a highly viscous fluid with a Reynolds number of 10^-7. This result suggests that the micro-machine has a great potential for medical applications. It was found that the optimum blade shape of the micro-machine varied with the Reynolds number condition.

抄録全体を表示

In a previous paper, the authors proposed a method for calculating the operating characteristics of a switched reluctance motor (SRM) on the basis of the general-purpose circuit simulation program "SPICE." The method was verified by experimental testing of a 4-phase 8/6 SRM. In the analysis, however, we neglected the effects of magnetic saturation. In this paper, we propose a SPICE model of the nonlinear reluctance of the SRM for analysis that takes into account of the magnetic saturation characteristics. The proposed model is verified by comparing the calculated magnetization curves obtained by using the model with those obtained by finite element analysis.

抄録全体を表示

Iron loss analysis of a permanent magnet motor was carried out taking account of the anisotropy of the magnetic material. Recently, it has become possible to measure magnetic material in terms of a vector quantity, as a result of improvements in measuring technique. Since the non-oriented silicon steel sheets used as the iron core material are anisotropic, it was necessary to carry out the analysis in such a way as to take account of the anisotropy of the magnetic material. We were able to do this by combining the finite element method with the Enokizono & Soda (E&S) modeling.

抄録全体を表示