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On a passive electromagnetic damper, optimum shapes of both a conducting slab and magnetic poles are determined by an optimization technique designed for compaction. Firstly, the optimum rectangular dimensions of the magnetic pole and the conducting slab were determined by this technique for several objective values of damping coefficient. Next, optimum shapes of the magnetic pole and the conducting slab were determined with reference to optimum rectangular shapes. Furthermore, these optimum shapes are verified experimentally.

The measurement method and the experimental results on the magnetic characteristics of oriented silicon steel in any direction are described in this paper. A single sheet tester of rotational loss has been used in order to simulate conditions existing in real devices. The flux of any direction is induced in the specimen by exciting from X and Y directions in the same phase. The flux density was measured by each search coil. The magnetizing force was measured by the double H-coil method. The outputs of the B-coils and the H-coils were treated by sending the outputs from the wave digitizer to the personal computer. The components of the magnetic characteristics in the X and Y directions for small values of B are the same. Only the saturation value changes, and it depends on the direction of flux.

The influence on electromagnetic force analysis of the difference between the magnetization characteristic used for calculation and the real characteristic is evaluated in this paper. The electro magnetic force is calculated by Maxwell's stress tensor method and the virtual magneitc charge method. The magnetic field used in these methods is analyzed by the FEM, using a magnetization characteristic. Comparison of the results calculated by using a magnetization characteristic and those calculated by using its transformed characteristics shows that the influence of the magnetization characteristics is small at low reluctivity, and is independent of the fineness of the mesh in the FEM. In addition, there is little difference between the methods of calculating the electromagnetic force with regard to the influence of the magnetization characteristic.

The purpose of this study was to develop a new online integrated backscatter intravascular ultrasound (IB-IVUS) system and to validate its ability to measure fibrous cap thickness by comparing IB-IVUS images with those from optical coherence tomography (OCT).Images were acquired from 125 segments of 26 coronary arteries obtained at autopsy from 11 cadavers. In the training study (n=30), 242 regions-of-interest on color-coded maps were compared with histology. In the validation study, 95 cross-sections were diagnosed by IB-IVUS and histology. In 24 patients with stable angina, 28 arterial cross-sections were imaged by IB-IVUS and OCT in vivo. In the training study, cutoff values of 39 decibels (dB) and 17dB were the optimal predictors of lipid pool/fibrosis and fibrosis/calcification, respectively, with 38-MHz mode; 42dB and 20dB, respectively, with 43-MHz mode. In the validation study, IB classified the fibrous, lipid-rich and fibrocalcific components with an accuracy of 92%, 91% and 95%, respectively. Agreement between the histological and IB-IVUS diagnoses was excellent (Cohen's κ=0.83). There was a correlation between the fibrous cap thickness measured by IB-IVUS and OCT (r=0.74, P0.001).The IB-IVUS system with improved resolution provides high diagnostic accuracy for the analysis of the tissue characteristics of coronary plaques, and enables estimation of the thickness of the fibrous cap in the clinical setting.

In this paper, combined analysis method of Electromagnetic and Structure analysis which describes how the magnetic steel sheet deformed by specifying the direction of nodal force against the element, in case the magnetic flux was distributed on it, was proposed. Deformation by magnetostriction of the magnetic steel sheet using structure and electromagnetic numerical analysis, and analysis of natural frequency and the result of measurement confirmed that the resonance occurred when magnetostriction frequency and natural frequency of the magnetic steel sheet were getting close. Also, larger resonance was confirmed when the shape of magnetic core deformed by magnetostriction and the eigen mode were close.

The nonconforming mesh connection technique is fairly effective for not only the analysis of electric machines with motion but also the reduction of the number of elements in a whole region of analysis. This paper describes the reduction method of computation scale by applying the nonconforming connection technique to the interface between the principal region including the electric machine and the outer space.

This paper investigates the acceleration of convergence to a steady state in a transient analysis of rotating machines using the time-periodic explicit error correction (TP-EEC) method. The efficient method to deal with the movement of the rotor and different time-periodicity in the fixed and moving parts of the mesh is developed. Numerical results verify the effectiveness of the developed method.

The magnetic characteristics in any direction were measured by using the single sheet tester for rotational loss. The measurement was made under conditions similar to those occurring in electrical machines and apparatus.

A technique for calculating the thrust of linear pulse motors is presented. This technique effectively uses the finite element method and the permeance analysis method to efficiently calculate the thrust with high accuracy. The utility of this technique was verified through the comparison of calculated and experimental results when applied to double-sided linear pulse motors with permanent magnets. The technique was applied to double-aided linear pulse motors, where the teeth of both the stator and the mover have simple rectangular shapes. The universality of this technique was verified by applying it to another model where the teeth of the mover have a trapezoidal shape. >

Shaded‐pole type induction motors are simple structure, strongly‐built and low cost since they have no condensers. Therefore they are used generally in cooling fans in the devices around computers etc., even though they are of low efficiency due to the power loss in the shading coils.

This paper presents a method of dynamic response analysis of a linear pulse motor under closed loop control, in which characteristics of the magnetic circuit and the control circuit of the motor are taken into consideration. This method was applied to a double-sided linear pulse motor with permanent magnets, and the influence of current control on the accelerating performance was investigated. The validity of the results was verified through comparison of computed and measured results. In addition, the optimum conditions for control were obtained from the results for the average dynamic thrust in each control mode.

The purpose of this study was to elucidate the usefulness of integrated backscatter (IBS) transesophageal echocardiography (TEE) for the evaluation of atrial degeneration and clarify whether atrial degeneration predicts the occurrence of atrial fibrillation (AF).One of the causes of AF is pathological degeneration of the left atrium (LA). However, there is no appropriate method to evaluate degeneration of the LA in the clinical setting.The IBS images were acquired with TEE with a 4- to 7-MHz transducer. The IBS values were calculated as the average power of the backscattered signal from regions of interest (ROI). In the pathological study, we measured IBS values of 21 left atrial specimens obtained from 10 autopsied hearts. Relative interstitial area in the ROI was automatically calculated by a personal computer. In the clinical study, we measured IBS values of the entire LA wall at 5-mm intervals (except the posterior wall) in 42 patients (18 non-AF patients, 14 paroxysmal AF patients, and 10 chronic AF patients). Each IBS value was color-coded to construct 3-dimensional maps.There was a weak correlation between the relative interstitial area and IBS values (r = 0.45, p = 0.038). Average corrected IBS values of total voxels in color-coded maps in the AF group (24.4 +/- 6.4 dB) and the paroxysmal AF group (23.9 +/- 9.6 dB) were significantly greater than those in the non-AF group (15.6 +/- 7.4 dB, p = 0.007), whereas there was no significant difference in LA diameter between the paroxysmal AF group (39.4 +/- 6.5 mm) and the non-AF group (36.7 +/- 5.5 mm).With IBS-TEE, we can identify an increase in atrial degeneration that might predict the occurrence of AF before LA dilation.

Background: It is well known that coronary plaques that show backward attenuation of ultrasound signal (AT) often cause distal flow disturbance during percutaneous coronary intervention (PCI). However, tissue characteristics of such plaques have not been precisely investigated. We previously developed an Integrated Backscatter Intravascular Ultrasound (IB-IVUS) for tissue characterization of coronary plaques. The aim of this study is to clarify the relationship among tissue components of coronary plaques, AT and distal embolization after stent deployment by use of IB-IVUS. Methods: In the pathological study, images were acquired from 221 segments of 18 coronary arteries from 13 cadavers obtained at autopsy. Twenty-three segments that showed AT (10%) were enrolled in this study. A total of 47 regions of interest (ROI) on histological images were compared with IB-IVUS color coded maps. Micro calcifications and cholesterol clefts were evaluated by von Kossa, Masson Trichrome and Hematoxylin-Eosin staining. Percentage of cholesterol clefts area (area of cholesterol cleft/area of ROI) and micro calcification area were calculated by a personal computer. In the clinical study, fourteen lesions which underwent elective stent deployment were enrolled. We evaluated the degrees of distal embolization by measuring serum troponin I (TnI) level before and after PCI and compared with IB-IVUS parameters. We defined the area of AT as the area where IB value is -6dB less than lipid pool. Results: In the pathological study, the attenuation of IB values of cholesterol cleft and micro calcification were3.58 ± 1.56 dB/0.1 mm and 3.51 ± 1.74 dB/0.1 mm, respectively. As the % cholesterol cleft area and % micro calcification area increased, the attenuation of IB values increased (r = 0.59 and 0.62, P < 0.001 and 0.001, respectively). Elevation of serum TnI have strong correlation to AT volume at the target lesions compared to the % lipid volume (lipid volume/plaque volume) (r = 0.92 and 0.56, P < 0.001 and 0.001, respectively). Conclusion: This is the first demonstration of the relationship among the attenuation of IB values, tissue component and distal embolizaion after PCI. This study provides new clinical insights to prevent and predict distal flow disturbance during PCI.

Integrated backscatter (IB) intravascular ultrasound (IVUS) and IVUS Virtual Histology (VH) have been developed for tissue characterization, but have never been compared directly. The purpose of this study was to compare the overall agreement between IB-IVUS and IVUS-VH in the tissue characterization of plaques from the same coronary arterial cross-section.Images were acquired from 46 coronary arteries from 25 cadavers. Of a total of 392 histology/IVUS image pairs, 152 pairs were diagnosed as Stary's type III, IV, Va, Vb and Vc, and compared for IB-IVUS, IVUS-VH and histology. In the qualitative comparison, the overall agreement between histological and IB-IVUS diagnoses was higher (kappa = 0.81, 95% confidence interval (CI): 0.74-0.89) than that of the IVUS-VH diagnoses (kappa = 0.66, 95%CI: 0.56-0.75). The % fibrosis area determined by IB-IVUS was significantly correlated with the relative area of fibrosis based on histology (r = 0.67, p0.001). In the quantitative comparison, the overall agreement between the histological and IB-IVUS diagnoses was higher (kappa = 0.83, 95% CI: 0.75-0.91) than that of the IVUS-VH diagnoses (kappa = 0.73, 95% CI: 0.63-0.83).Based on histology as the gold standard, IB-IVUS provided higher diagnostic accuracy than IVUS-VH for tissue characterization of coronary plaques.

The optimum shape of a conductor slab on an electromagnetic damper is determined by an optimization technique by the use of the Lagrange method of multipliers taking a serious view of a compact design. Firstly, damping coefficients were obtained by analysis of the eddy current in the conductor slab by the boundary element method combined with the finite element method. The numerical result agrees well with the experimental result in our previous report. Secondly, the optimum dimension of rectangular conductor slab was obtained by the least-square method and the optimization technique. The result of the optimization is verified in good agreement with the result of the least-square method. Thirdly, the optimum shape of conductor slab determined by the optimization technique. Furthermore the result is verified by an experimention.

The fluctuation of flux density and shape effect of conductor slab on an electromagnetic damper, which consists of rectangular magnetic poles and a conductor slab, are clarified by the finite element anaysis and an experimentation. Firstly, we measured the flux density distribution near magnetic poles by the use of Hall elements, while the conductor slab vibrating in the magnetic field. The result verifies the numerical result in our first report. Secondly, attenuation coefficients were obtained under several dimensional ratios of conductor slab to magnetic pole, experimentally and numerically. The experimental result agreed well with the numerical result. Thirdly, a relation between conductor shape and eddy current distribution is also discussed numerically.

Background: We developed an Integrated Backscatter Intravascular Ultrasound (IB-IVUS) for tissue characterization of coronary plaques. The relationship between the coronary artery distensibility and tissue components has not been investigated. Methods: Fourty-seven plaques with moderate stenosis (30 to 50%) in 36 patients were evaluated by three-dimensional (3D) IB-IVUS at every one millimeter. Plaque distensibility, lumen distensibility, vessel area, lumen area (LA) and plaque area (PA) were measured. Plaque distensibility was defined as follows: [In (systolic BP/diastolic BP)]/[(diastolic PA - systolic PA)/diastolic PA]. Lumen distensibility was defined as follows: [In (systolic BP/diastolic BP)]/[(diastolic LA -systolic LA)/diastolic LA]. % lipid area (lipid area/plaque area) were automatically calculated by IB-IVUS. Results: As the % lipid area increased, the lumen distensibility also increased (r = 0.32, p = 0.040). There was a tendency that the plaque distensibility increased as the % lipid area increased (r = 0.31, p = 0.056). 3D plaque distensibility map showed the difference in the plaque distensibility of each segment well. Conclusion: This is the first clinical demonstration of the relationship between the % lipid area and plaque distensibility of coronary arteries. The plaque area with greater % lipid area were more likely to increase from systolic to diastolic phase. 3D IB-IVUS color-coded mapping is useful for the evaluation of tissue characteristics and dynamics of coronary plaques.

The solar spectrum is presumed by using measurement irradiance, and it proposes the calculation method of irradiance corresponding to the spectral response of the solar module by using the spectrum. The influence that the change of the solar spectrum gives to a-Si solar module and poly-Si solar module is examined regarding the time, the season, and the tilt angle. In this thesis Bird Model, a spectrum calculation at fine weather, is corrected by the data of measured irradiance, the date, and time. It proposes the technique for presuming the solar spectrum corresponding to the break in the weather. The irradiance corresponding to the spectral response is calculated by the thesis, then by applying the I-V characteristic, the power generation is presumed and the effectiveness of this theory is examined

In a recent issue of iJACC , Prati et al. [(1)][1] suggested that plaque characterization by newer imaging modalities such as intracoronary optical coherence tomography (OCT) may help optimize management strategies in acute coronary events. Although OCT imaging has been extensively performed for

A novel high power factor converter is presented in this paper. The proposed converter is a high-frequency forward converter controlled by a magnetic amplifier. This converter has no need of special control to correct the power factor. Power factor is corrected by the automatic variation of the saturation time of the magnetic amplifier according to the input voltage variation. The current stress of the transistor switch is low because this converter operates in the continuous conduction mode of the inductor current. The circuit operation is verified experimentally at a frequency of 500 kHz.

The experience of using a novel application of intravascular ultrasound (IVUS)-guided percutaneous coronary interventions for chronic total occlusions is reported in 2 cases. In the first case, an IVUS catheter was advanced into a side branch to identify the entry point of the major branch. In the second case, IVUS-guided penetration of the guidewire from the false lumen to the true lumen after causing a dissection was successful. (Circ J 2004; 68: 1088 - 1092)

This paper presents a technique for a magnetic field analysis using the Finite Element Method (FEM) which is applied to the rotatory movement of rotating machinery. The proposed technique uses only a couple of meshes because the nodes on an interface are joined under the unknown equal potential condition. This technique is examined by the analysis of the characteristics of brushless DC machines. Calculated results by this technique agree well with the measured ones, so that the utility of this technique is confirmed. >

Although coronary perforation can cause tamponade during percutaneous coronary intervention (PCI), this is unusual for patients previously undergoing coronary artery bypass graft surgery (CABG) due to pericardial adhesions. We report here on a rare case of right ventricular out-flow obstruction complicating PCI in a patient with a previous CABG.

A novel zero-voltage-switching (ZVS) PWM half-bridge power converter is presented. The proposed power converter consists of a conventional half-bridge power converter and two added switches in series with the secondary rectifier diodes. This power converter is controlled by PWM of the main switches using a novel switching sequence with constant switching frequency. The zero voltage switching of the main switches is maintained by partial resonance during the interval where both the main switches are off, and the secondary switches turn on and off with zero voltage and zero current. The operation of this power converter is described by use of equivalent circuits and is verified by experiments. >

BAlGaN and (BAlGaN/AlN) multi-quantum-wells (MQWs) structure were grown on 6H-SiC substrate by a low-pressure metalorganic vapor phase epitaxy (LP-MOVPE). Estimated boron compositions of the BAlGaN quantum wells by an Auger electron spectroscopy (AES) analysis were 0% to 13%. Photoluminescence (PL) spectra around 260 nm were observed at room temperature. The full-width at half maximum (FWHM) of PL spectra for BAlGaN/AlN MQW structure(with 2% of boron) was narrowed from 360 meV to 179 meV, as the residual strain in the BAlGaN well layer was decreased from 1.3% to 1.0% by increasing the Al content in the quantum wells.

In this paper, 3-D FEM analysis is employed for these transformers, in which the external electric components, i.e., battery and diodes are taken into account. The utility was verified through the comparison of calculated and measured results.

Kinetics of poly(-D(−)-3-hydroxyalkanoate) (PHA) production were studied in Alcaligenes eutrophus H16 (ATCC 17699) fed-batch culture using butyric acid and valeric acid as carbon sources. In poly(-D(−)-3-hydroxybutyric acid) (PHB) production, at the conditions of 3g/l butyric acid concentration and pH 8.0, the maximum values of specific production rate of PHB, production yield, and PHB content in the cell were obtained. Effect of cultivation condition on molecular weight distribution of PHB was studied. The average of molecular weight was decreased as the butyric acid concentration was increased. When the nitrogen source was added to the fermentation medium after adequate PHB accumulation in the cell, not only PHB production but also degradation were simultaneously occurred. The degradation rate of low molecular weight polymer was higher than that of high molecular weight polymer, and as a result, the average of molecular weight distribution shifted to the higher value. By addition of valeric acid to the butyric acid as carbon sources, copolyester of 3-hydroxybutyric acid (3HB) and 3-hydroxyvaleric acid (3HV), which is abbreviated as P(3HB-co-3HV), was produced but the specific production rate was lower than that of PHB. The mole fraction of P(3HB-co-3HV), was also investigated, using butyric acid and valeric acid as carbon sources. The mole fraction can be controlled within a range of compositions (0-40 mole% 3HV) by the mole ratio of butyric acid and valeric acid in the feeding medium.

This paper investigates a large-scale analysis of magnetic particles’ behavior in magnetic fields by using a novel method combining the discrete element method and the magnetic interaction calculation with the fast multipole method (FMM). Furthermore, the effective formulae for the derivative of the magnetic field in the FMM procedure, which is necessary to calculate magnetic forces among a large number of magnetic particles, are proposed. Numerical examples of large-scale magnetic-particle chain analysis that demonstrate the effectiveness of the proposed method are presented.

An international round robin supported by the Japanese Government has been started in order to establish the IEC standard of measuring the magnetic characteristics of amorphous magnetic materials. Several kinds of single sheet testers are produced and automatic measuring systems are prepared at 6 countries. Power loss and exciting VA are measured and the accuracies are compared.

The magnetostriction characteristics of a silicon steel sheet with a bias field have been measured using a modified single sheet tester (SST). The magnetostriction characteristics of the sheet change remarkably under the influence of an exciting dc field.