Studies of the network structure of rubber vulcanizates by cryoscopic methods: 2

The freezing point depression, ΔT, of swollen DCP-, TT- and sulphur-cured natural rubber in benzene was observed. The dependence of the parameter, a_H, introduced by Kuhn, was not affected by the type of structure of crosslink sites. It was found from the comparison of the experimental results and scaling law that a_H can reflect not only the difference in three-dimensional structure of network between a degraded and an undegraded rubber vulcanizates but also the difference in degraded network structures between rubber samples with various conditions of degradation.     

Performance of Transform Coding for Carrier Chrominance Signals

This paper describes the results of theoretical studies made on performance of various kinds of intrafield two-dimensional transform codings (Hadamard, cosine, and slant) for carrier chrominance signals, by introducing a new measure (transform coefficients of zero variance) for such coding performances. In addition, a comparative study of the performance of these transform codings is performed for different sampling frequencies(2f_{sc}, 3f_{sc}, 4f_{sc})with the same transmission rate, taking into account the tradeoff between the number of bits assigned to a picture element at each sampling frequency and the autocorrelation between adjacent picture elements.     

Structural determination of a mutagenic aminophenylnorharman produced by the co-mutagen norharman with aniline

Norharman (9H-pyrido[3,4-b]indole), widely distributed in our environment, including cigarette smoke and cooked foodstuffs, is not mutagenic to Salmonella strains, but becomes mutagenic to S.typhimurium TA98 and YG1024 with S9 mix in the presence of non-mutagenic aromatic amines such as aniline and o-toluidine. To elucidate the mechanisms of co-mutagenicity, we tried to isolate the mutagen(s) produced by a reaction between norharman and aniline with S9 mix. By HPLC purification, two mutagenic compounds (I and II), one (I) showing mutagenicity with and the other (II) without S9 mix, were isolated. The structure of compound I was deduced to be a coupled compound of norharman and aniline, 9-(4'-aminophenyl)-9H-pyrido[3,4-b]indole (aminophenylnorharman), by a variety of spectrometry techniques and this was confirmed by its chemical synthesis. The mutagenic activity of this novel heterocyclic amine was tested using the pre-incubation method and was found to induce 187,000 revertants in TA98 and 1,783,000 revertants in YG1024 per microg with S9 mix. Compound II was shown to be hydroxyaminophenylnorharman. Formation of the same DNA adducts was observed in YG1024 when aminophenylnorharman or a mixture of norharman plus aniline was incubated with S9 mix. The hydroxyamino derivative also yielded the same DNA adducts in YG1024. Thus, the appearance of mutagenicity by norharman with aniline in the presence of S9 mix suggests that the coupled mutagenic compound, aminophenylnorharman, is formed from norharman and aniline, then converted to the hydroxyamino derivative and forms DNA adducts to induce mutations in TA98 and YG1024.     

An aggressive nasal lymphoma accompanied by high levels of soluble Fas ligand

10 adults' performances on visual training through recognition of speech spectrograms were examined. All subjects completed the training within eight 1-hr. sessions. Success and retention of training were also evident in the subjects' performances on two posttests.     

TAT (time-axis transform) bandwidth compression system of picturesignals

A bandwidth compression system for picture signals called the time-axis transform (TAT) system is introduced. It can be applied to various systems for transmission and recording of picture signals, such as the satellite broadcast system of high-definition television. The TAT compresses the bandwidth by reducing the number of transmitted pixels. The transmitted pixels consist of two kinds: basic pixels and additional pixels. The location of the former is fixed and that of the latter varies from picture to picture to minimize the interpolation error in the reconstructed picture. Thus, the TAT is a hybrid of fixed sampling and variable sampling systems. It compresses the bandwidth of the picture signal to one half or less, keeping high picture quality for both still and moving pictures. The feasibility of the TAT is demonstrated by an experimental system     

Simultaneous Active and Reactive Power Control of Superconducting Magnet Energy Storage Using GTO Converter

By using GTO's (Gate Turn-Off Thyristor) in place of ordinary thyristors in a conventional six pulse Greatz bridge converter, forced commutation is possible, so in the usage of ac-dc power conversion the reactive power of not only lagging but also leading phase can be absorbed. This feature enables superconducting magnet energy storage (SMES) to control reactive power in the wide range between lagging and leading phases. By virtue of this control ability , SMES will be applicable for a power system stabilyzer. A GTO converter which mainly consists of six GTO's was developed and tested. In this GTO converter, the energy stored in leakage inductances of the transformer is handled by voltage clipper circuit. Then, by using two sets of these GTO converters, we carried out some experiments of simultaneous active and reactive power control of SMES. The experiments on the developed control system were successfully performed and the ability of controlling reactive power in the wide range between lagging phase and leading phase was verified.