Showing papers in "Ieej Transactions on Fundamentals and Materials in 2001"

カリフォルニア工科大学 (California Institute of technology) 滞在記

Abstract: September 19-20 International Student Orientation September 22 New Student check-In for Undergraduates September 22-29 New Student Orientation for Undergraduates September 23 New Student Check-In for Graduates September 23-27 New Student Orientation for Graduates September 26 Undergraduate Academic Standards and Honors Committee – 1:00 p.m. September 27 Undergraduate Academic Standards and Honors Committee Appeals– 1:00 p.m. September 30 Rosh Hashanah – classes excused October 1 Beginning of instruction 8:00 a.m. October 18 Last day for adding courses and removing conditions and incompletes October 30Midterm examination period November 5 November 11 Midterm deficiency notices due 9:00 a.m. November 20 Last day for dropping courses, exercising pass/fail option, and changing sections November 21Registration for winter term 2019-20 December 6 November 28-29 Thanksgiving (Institute holiday) December 6 Last day of classes Last day to register for winter term 2019-20 without a $50 late fee December 7-10 Study period December 11*-13 Final examinations, fall term 2019-20 December 13 End of fall term 2019-20 December 14Winter recess January 5 December 18 Instructors' final grade reports due 9:00 a.m. *First due date for final examinations

Properties of Liquid-Jet Induced by Electrohydrodynamic Pumping in Dielectric Liquids

Abstract: Liquid-jet phenomena induced by electrohydrodynamical (EHD) pumping were investigated in isothermal dielectric liquids without direct charge injection at a metal/liquid interface. A pseudo-doughnut to plane electrode system was used to generate an EHD liquid jet, and the liquid jet properties were measured using four different dielectric liquids (which are referred to as DBDN, BCRA, Tr-Oil, and FS-Oil in this paper). The maximum velocity and pumping pressure achieved were 1.5 m/s and 5.5 kPa, respectively, at an applied voltage of 23 kV with approximately 2.5 W of electrical power consumption in BCRA. It is considered that this liquid jet is due to pure conduction pumping. This mechanism is associated with heterocharge layers near the electrodes which are based on the process of dissociation and recombination of the electrolytic species. Furthermore, to obtain high directivity of the liquid jet, two special nozzles (herein referred to as a normal nozzle and spiral nozzle) were designed. A highly directed liquid jet was obtained using the spiral nozzle. In this case, the flow pattern was of a spiral structure. It is considered that this spiral jet is produced by both the Coanda effect and the nozzle shape (conical hole). © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 1–9, 2002; DOI 10.1002/eej.1132

Numerical Analysis of Plane Wave Diffraction by a Semi-Infinite Grating

Abstract: Plane wave diffraction by a semi-infinite strip grating is analyzed in order to investigate the end-effect of finite gratings in pure form. In the formulation, the current induced on each strip is divided into periodic current on an infinite strip grating and the correction current induced by the truncation of the periodic structure. These currents are determined by solving a set of integral equations by using the method of moment. Numerical calculations for current distribution, diffraction patterns, and norm of the induced correction currents reveal the end-effects of the semi-infinite grating.

Application of Feature Extraction Scheme to the Discrimination of Electrocardiogram (ECG)

Abstract: Electrocardiograms (ECGs) used for the diagnosis of heart diseases generates large amounts of time-series data. They are regarded as hyperdimensional data. The number of dimension is that of sample points. To automatically recognize any abnormality in the ECG it is essential to extract significant features from the hyperdimensional ECG data. We have already developed a method for purpose-oriented feature extraction and successfully applied it to hyperspectral data which have several hundreds of dimensions. Here we apply the basic idea of this method to the analysis of 12-lead ECGs for the discrimination of abnormal waveforms. ECG data were acquired from normal subjects and from patients who seemed to suffer from one of three classes of abnormalities (anterior myocardial infarction, inferior myocardial infarction, and flattening of the T wave). A small number of features appropriate for discriminating significant patterns of the ECG were extracted. Our method can efficiently process the data and give results relevant to the purpose of diagnosis.

History of Power Electronics in Japan

Abstract: Power electronics today is one of a wide range of well defined technologies. It has a key role in the transformation and adaptation of electrical energy between the supplier and the user. The object of this paper is to review the history of power electronics in Japan. Considering general trend, important researches and epoch-making new products are listed in several important areas. Technical events from overseas, which caused great impacts in Japan, are also cited.

Preparation of B4C Thin Film by Intense Pulsed Ion-Beam Evaporation

Abstract: Boron carbide (B4C) is known as a material having hardness, wear resistance and stability at high temperature. The preparation of thin films of B4C, therefore, is very important from the viewpoint of industrial applications. We have experimentally attempted to prepare thin films of B4C using the pulsed ion-beam evaporation (IBE) technique, where high-density ablation plasma is produced by an intense pulsed ion beam interaction with the target. The crystallized B4C thin films have been successfully deposited on a Si (100) substrate by front-side and mask-side deposition. Absorptions associated with the B–C combination and the vibration of B12–B12 clusters have been observed by Fourier transform infrared spectroscopy. The Vickers hardness of the film deposited by front-side deposition is observed to be HV~2300.

Development of High-Tc SQUID Magnetometer for MCG Measurements of Small Animals

Abstract: We have developed a magnetometer system using high-Tc SQUIDs, aiming to use in a basic physiological study of cardiac functions of small experimental animals. A cryostat was prepared to have a spacing of 3mm between the air and nitrogen at the bottom, where the capacity of liquid nitrogen was about 4L. Two direct-coupled SQUIDs were located within the cryostat in such a manner that a reference SQUID that detected environmental field noise was placed 8.5cm above a sensing SQUID. The feedback current of the reference SQUID was also supplied to the same type of coil at the sensing SQUID, to form a gradiometer at the level of signal detection. The whole system was operated within a magnetically shielded room having an attenuation of 50dB at low frequencies. The effect of the direct-feedback gradiometer to reduce external field noises was confirmed, where more than 20dB attenuation was obtained for the largest 50Hz noise in the shielded room. MCG signals of anesthetized rats were measured in a wide bandwidth of 0.5-200Hz.