This article has no abstract.

View full abstract

There has been increasing public concern about the adverse health effects of human exposure to radio frequency fields. Radio frequency fields are also used for medical application. This paper reviews electromagnetic and thermal computational dosimetric techniques, which has been developed by the authors. The feature of the thermal dosimetric method is that body core temperature can be computed reasonably unlike conventional method. This scheme is particularly useful for intense localized or whole-body electromagnetic wave exposure. Computational examples are shown to verify the effectiveness of the proposal.

View full abstract

Recent trends of optical emission spectroscopic measurement of atmospheric pressure plasmas are reviewed for the determination of electron temperature and density. Some methods to estimate the electron temperature and density are reviewed, based upon the quantitative description of the excitation kinetics in the non-equilibrium plasmas. Line intensity measurement methods are reviewed for atmospheric-pressure Ar plasma and low-pressure N₂ plasma.

View full abstract

Recent trends of CVD techniques by using moderate-pressure microwave plasmas are reviewed. Microwave plasma sources generate stable and high-density plasmas typically at pressures of 10 to 100 Torr. They have been developed exclusively to deposit artificial diamond films and are increasingly used to deposit nanostructured carbon materials. The deposition mechanism and electrical properties of nanocrystalline diamond films and carbon nanowalls are described.

View full abstract

Lightning and sprite measurement sensors on the International Space Station (ISS) are introduced in this paper. Lightning is an electrical discharge which neutralizes the charge inside thunderstorm. In the early 1990s, optical transient luminous events (TLEs) occurring just above the thunderstorm were firstly reported by the US scientists and are associated with positive cloud-to-ground discharges with a large amount of charge. Though the luminous events so-called sprite, elves and jets have been investigated by numerous researchers all over the world based mainly on the ground observations, some important problems have not been fully understood yet such as generation mechanisms of columniform fine structure and horizontal offset of some sprites from the parent lightning discharges. In the JEM-GLIMS mission, observations from our synchronized sensors are going to shed light on above-mentioned unsolved problems regarding TLEs as well as causative lighting discharges. Our goals are (1) to detect and locate lightning and sprite within storm scale resolution over a large region of the Earth's surface along the orbital track of the ISS without any bias, (2) to clarify the generation mechanism of sprite, and (3) to identify the occurrence conditions of TLEs.

View full abstract

Compact and coherent light sources are key components for development of terahertz frequency range in which various applications are expected. Recent progress in room-temperature terahertz oscillators using resonant tunneling diodes are shown here. Fundamental oscillation up to 1.04 THz has been achieved with a structure having short transit time of electrons. This is the first oscillation above 1 THz in room-temperature electronic single oscillators. Structures for high output power, frequency change with bias voltage, and spectral linewidth are also described.

View full abstract

Instrumentation and measurement play a vital role in research and development in the science and engineering fields. Recently, the goals of instrumentation and measurement have expanded to meet not only the industrial and science requirements but also the needs in all fields of social life, such as medicine and welfare, the environment, and disaster and security.
In this article, recent technical topics in the instrumentation and measurement field are reported.

View full abstract

This is a review of the 41st Symposium on Electrical and Electronic Insulating Materials and Applications in Systems (SEEIMAS) hosted by Technical Committee on Dielectrics and Electrical Insulation (TC-DEI) in IEEJ in order to overview the research trend in this specific field. Nano-composite materials, insulation systems under inverter surges, space charge assessment, asset management regarding to insulation performance, outdoor insulations, thin dielectric films and other topics are dealt with. The proceedings booklet in Japanese, with English abstract and figure captions for each presentation, will be available at the IEEJ office.

View full abstract

Recent developments and their applications of superconducting detectors that directly detect the incidence of photons and particles will be reviewed. Transition-edge sensors, superconducting single-photon detectors and superconducting stripline sensors are included in this category. Their recent progresses in new application fields, such as quantum information communication and time-of-flight mass spectrometry, will be shown.

View full abstract

A transformer possesses several functions, such as insulation, voltage transformation, impedance transformation, and so forth. Similarly, an inductor or a reactor is used for current ripple reduction, resonance, energy storage, and so on. Those magnetic power devices are separately placed and connected to circuitries so far. On the other hand, cost reduction is strongly required in designing power supplies. Therefore, power circuit engineers always consider the ways to reduce the number of circuitries.
In this article, we introduce recently developed technologies that reduce the number of circuitries in DC-DC converters by synthesizing the functions of a transformer and an inductor.

View full abstract

Influences of metal-ion adulterations into Polymer Electrolyte Fuel Cells (PEFC) were examined on PEFC generation characteristics and structural changes. Cupper and aluminun, novel candidate materials for forthcoming PEFC system, were introduced into polymer electrolyte membranes (PEM) by ion-exchange method as contaminants, and ca. 500-hour generation tests of PEFC cells with these PEMs were conducted in this study. Introduced metal ions were to be combined to sulfonic acid groups in PEMs by electrostatic forces. For the cell containing cupric ions (Cu²⁺) equivalent to 1000 pmm of supfonic acid groups in PEM, a decrease in deteriorating rate of cell voltage was observed to be 83 mV/kh during 500-hour generation, in comparison with the cell without metal-ion comtamination showing 154 mV/kh. On the other hand, an increase in deteriorating rates were observed for the cells containing 10 % Cu²⁺ or 1000 ppm aluminum ions (Al³⁺). Al³⁺ adulteration in PEFC set off increases in activation overpotential and fluoride ion release rate (FRR) with proceeding genaration test. An increase in activation overpotentials was supressed in 1000 ppm Cu²⁺-adulterated cell and the reverse was observed in 10 % Cu²⁺-adulterated one, though Cu²⁺ adulterations suppressed growths of platinum catalyst particles in size and FRR regardless of Cu²⁺ concentration. Restriction effect of 1000 ppm Cu²⁺-adulteration into PEM on PEFC voltage deterioration has found to be the unprecedented knoledge with respect to PEFC degradation phenomena. Mechanisms of those influences were also discussed.

View full abstract

Autofluorescence of refrigerated raw scallop adductor muscle was investigated. Fluorescence of reduced nicotinamide adenine dinucleotide (NADH) with peak wavelength at 458 nm was observed in fresh scallops. The fluorescence emission intensity of NADH decreased until 48 hours in the storage time at time. As for the fluorescence excitation spectra, the peak wavelength became long from 361 to 369 nm as the storage time became long.

View full abstract

We examined the possibility of the preference evaluation of the taste that used the near-infrared spectroscopy. As a result, the possibility of the objective evaluation by fNIRS was shown.

View full abstract

We developed a new application of the electric double layer capacitor (EDLC) as a sec-order quasi-DC power supply like flying-wheel motor-generators. We constructed the power supply using IGBT switching circuit and successfully demonstrated its initial operation whose current and duration time are 100A and 3sec, respectively, indicating a new potential of EDLC.

View full abstract