Structural interpretation of plasma-polymerized propargyl alcohol

Vapor of propargyl alcohol under reduced pressure was glow-discharged for plasma polymerization by which hydrophilic polymer film could be deposited onto a solid substrate. The hydrophilic property was more enhanced with use of the same monomer containing water. An interpretation of chemical structures of the polymer molecules was therefore attempted to discover the reason of the hydrophilic property. The polymer materials were subjected to IR spectroscopy, ¹³C-NMR and ¹H-NMR spectroscopies, elemental analysis, number average molecular weight determination, mass spectrometry, and other wet chemical analysis for . The IR spectra of the polymers showed the presence of OH, C?O, and C?C groups with a disappearance of C?C group of the monomer. It was also found that the molecular formula of a solvent extract of the polymer derived from the plain monomer was C₂₆H₃₆O₉ ≒ 490, involving four hydroxyl, one carbonyl, and two to three olefinic unsaturation groups within a unit molecule. On the other hand, the polymer from 60% water-containing monomer showed its molecular formula as C₄₄H₆₆O₁₈ ≒ 890, containing seven to eight hydroxyl, two carbonyl, and one to two olefinic unsaturation groups. This information was used to establish the symbolic chemical structures of the polymer molecules. It has been found that both polymers were not as much crosslinked as other plasma polymers because of having side chains with fewer branching. The oxygen atoms were retained in the polymer not only as the forms of OH and C?O but also as a member of the principal frame of the polymers.     

The effect of space charge on the initial growth of electrical trees in polyethylene

This paper describes the influence of space charge on the growth of an electrical tree which is an important factor of the dielectric breakdown in polyethylene-insulated power cables. Polyethylene and ethylene vinyl-acetate copolymer with a semi-conducting needle were used as the treeing specimens. The statistical analysis showed that the growth rate and the unbalance of positive and negative partial discharges increased as the vinyl-acetate content increased, and that the growth per cycle decreased with the increase in frequency. A model of the tree growth accompanied by the space charge behavior was proposed considering the above experimental results. The tree growth is considered to be caused by the dielectric breakdown due to the field enhancement at the tree tip during the positive half cycle of the applied voltage, the field enhancement being due to residual negative space charge injected during the previous negative half cycle. The negative space charge in polyethylene would be mainly supplied through the partial discharge inside the tree.     

Basic study on calibration using waveform variation in space charge measurement by pulsed electroacoustic method

The pulsed electroacoustic method determines the distribution of space charge in an insulation system by applying a pulse voltage and detecting the acoustic response. It estimates the location and magnitude of charges from time-domain signals. For quantitative analysis, a bias voltage is applied to a specimen with no space charge, and the acoustic signal generated from the electrodes only is used as a reference waveform for calibration. However, a full-scale, extra-high voltage insulation system often already contains space charges in it. Therefore, a method of acquiring a reference signal under such a condition was studied. We studied methods to compare voltage variations and response signal variations. We proposed a method that measures the signal difference at different voltages. In addition, we proposed a method of correlating voltage and signal variations that may allo for more rapid signal acquisition. The feasibility was proved using an 11 mm-thick mimic polyethylene specimen.     

A field‐emitter‐array cathode‐ray tube (FEA‐CRT)

Abstract— High‐resolution bright CRT monitors with Spindt‐type field‐emitter arrays (FEA‐CRTs) as electron guns have been realized for the first time. The FEA chip consists of 868 electron sources arranged within an emitter circle 50 μm in diameter and a vertical current limiter (VECTL) which protects the FEA chips from damage caused by an arc electric discharge. The FEA‐CRT has a minimum electron beam diameter of 0.84 mm at 18 kV and 100 μA.     

H Robust servo problem with H∞ norm constraint

A robust servo problem with an H-infinity norm constraint is investigated based on the LMI (Linear Matrix Inequality) approach to the H-infinity control problem. The following results are obtained. (1) A necessary and sufficient condition for the existence of an H-infinity controller with robust tracking property is derived. It consists of the following two indepent conditions: (i) the existence of an H-infinity controller; (ii) a boundary constraint at the reference mode. (2) If there exists an H-infinity controller with robust tracking performance, there exists one whose order equals the sum of an H-infinity controller and the internal model.     

BUP: A Bottom-Up parser embedded in Prolog

A parser based on logic programming language (DCG) has very useful features; perspicuity, power, generality and so on. However, it does have some drawbacks in which it cannot deal with CFG with left recursive rules, for example. To overcome these drawbacks, a Bottom-Up parser embedded in Prolog (BUP) has been developed. In BUP, CFG rules are translated into Prolog clauses which work as a bottom-up left corner parser with top-down expectation. BUP is augmented by introducing a “link” relation to reduce the size of a search space. Furthermore, BUP can be revised to maintain partial parsing results to avoid computational duplication. A BUP translator and a BUP tracer which support the development of grammar rules are described.     

Relationship between electron sensitivity and chemical structure of polymers as EB resists. I. Electron sensitivity of various polyamides

Polyamides containing double bonds or epoxy groups were synthesized and evaluated as electron beam (EB) resists, in order to find the relationship between electron beam sensitivity and chemical structure of the polyamides. It was found that polyamides containing double bonds, which have good solubility, are easily crosslinked by the electron beam exposure. The sensitivity of a polyamide with 70 mol% of the repeat units containing double bonds was equivalent to that of a 100% unsaturated polyamide which contained double bonds of 100% molar ratios, and thus it is not necessary that the polyamide be a homopolymer of unsaturated repeating units. The polyamides have good physical properties, and are adaptable to dry etching processes.     

Fretting wear of Al-Si alloy matrix composites

Ball-against-disk type fretting wear tests for Al-Si alloy matrix composites in contact with bearing steel were conducted in wet air to investigate the effects of relative slip amplitude on friction and wear of the composites. In the larger range of relative slip amplitude, the Al-Si alloy-impregnated graphite composite (ALGR-MMC) shows lower friction coefficients than those of alumina short fiber-reinforced composite (ASFR-MMC) and hollow silica particle-reinforced composite (HSPR-MMC). Although the wear rate of the ALGR-MMC is higher than that of the ASFR-MMC and HSPR-MMC, the composite hardly causes damage to the mating material due to adhesion of compacted films of graphite powder and Al-Si alloy wear particles.