Solubility of argon in acetone + water mixed solvent at 288.15, 298.15 and 308.15 K

Solubilities of argon were determined in acetone + water mixed solvent over the full range of composition using a static method. The gas solubilities were measured at three temperatures of 288.15, 298.15 and 308.15 K. The solubility dependence on the temperature in the mixed solvent was measured and discussed, and the similarity between excess quantities of mixed solvent and those of gas solubilities was examined. The order of gas solubility of argon in acetone + water mixed solvent at the three different temperatures was 288. 15 > 298.15 > 308.15 K in the composition range of 0 ≤ x₂2 ≤ 0.15. However, the reverse relationship with temperature was observed in the range of composition of 0.15 < x₂ ≤ 1.0. For all solubility curves, maximum and minimum values of solubility were observed at lower temperatures, but not at higher temperatures. Furthermore, the excess Ostwald coefficients on the basis of volume fraction which express the non-ideality of gas solubility in non-ideal solutions were defined, and they were expressed by a polynomial equation of the Redlich-Kister (1948) type.     

Effects of reactive gas addition on ionization of metal atoms in droplet-free metal ion sources

This paper reports on influences of reactive oxygen (O₂) or nitrogen (N₂) addition on ionization characteristics of sputtered titanium (Ti) atoms in an argon (Ar)-based novel droplet-free metal ion sources. Although Ti atoms had a pressure dependence of ionization characteristics similar to copper ones in a pure Ar discharge, the ionization characteristics of Ti atoms were affected by adding reactive N₂ and O₂ gases into the Ar plasma. Especially, the reactive gas addition significantly reduced fluxes of Ti atoms and Ti⁺ ions probably due to target-poisoning effect caused by chemical reactivity of Ti. Even adding the reactive gases, the source will still work as a droplet-free metal ion source since the ionization fraction of Ti atoms reached over ∼ 90%. Optimization of discharge conditions and reactive gas provision will be necessary from a metal ion process point of view.     

Optimization of low‐temperature poly‐Si TFT‐LCDs and a large‐scale production line for large glass substrates

Abstract— An update of the progress of inherently low‐temperature poly‐Si (LTPS) technologies, such as ELA, ion doping, and activation in conjunction with chemical vapor deposition (CVD) and photolithography will be given. We will also discuss whether LTPS LCDs will be applied to a large‐scale production line using a large motherglass substrate. It was found that a more‐powerful excimer laser as well as photolithography with higher‐resolution and a more‐precise overlaid arrangement would enable a large‐scale production line handling motherglass of 4th generation size to be constructed in the very near future with reasonable investment and productivity costs.     

Change of amorphous state of poly(ethylene terephthalate) by heat treatment below the glass transition temperature

Several papers have demonstrated that structural changes in the amorphous regions of semicrystalline polymers can be produced by heat treatment below the glass transition temperature (T_g). In this paper, we report structural change in the amorphous phase of poly(ethylene terephthalate), heat-treated below and above T_g. The density, the T_g, the endothermic peak at T_g and the relative spectral intensity in the 973 cm^?1 band (due to the CO stretching vibration), all increased with heat treatment below T_g, but the specific heat decreased. The stability of the amorphous state was examined by further heat treatment at temperatures above T_g and sufficiently high for crystallization, and it was verified that structural changes in the amorphous regions do not result in acceleration of the rate of crystallization. We therefore suggest that the amorphous region is one phase, rather than two phases consisting of random and regular regions.     

Direct Determination of Grain Growth Behavior in Zinc Oxide with Added Barium Oxide

Grain growth behavior in ZnO with 4 to 12 wt% BaCO₃ (3.12 to 9.59 wt% BaO) added was studied by a new method, in which the sintered specimen was treated with boiling water to separate the grains by dissolving the grain-boundary phase. The separated grains were examined with SEM to obtain quasi-three-dimensional information on the grain shape, size, and size distribution. The grains had a rounded shape, and the size distribution was found to be lognormal.     

Optical resolution of 2-alkanol by lipase-catalyzed acetylation with vinyl acetate in packed-bed reactor with recycling system

The lipase-catalyzed acetylation of 2-alkanol with vinyl acetate was studied using Burkholderia cepacia lipase (BCL), three alcohol and three organic solvents in a packed-bet reactor with a recycling system (flow method). The optical resolution data were found in agreement with those of the batch method in which BCL was suspended in the substrate solution. Repeated reaction results clearly indicated BCL in the packed-bed to be quite stable and to be usable for at least 50 reaction runs or to remain effective for as long as two months in the water-insoluble solvents such as hexane and 1,2-dichloroethane. In the reaction using a water-soluble solvent such as acetonitrile, the catalytic power of BCL showed only a 1% decrease of conversion per run or solvent recycling possibly owing to compression of BCL in the bed although enantioselectivity was independent of the number of reaction repetitions. The present method showed thus be applicable to kinetic resolution by enzyme-catalyzed acylation in hydrophobic organic solvents with no waste of enzyme.     

Supramolecular method for the determination of absolute configuration of chiral compounds: theoretical derivatization and a demonstration for a phenolic crown ether-2-amino-1-ethanol system

A combination of anisotropic shielding effect and temperature dependence of NMR chemical shifts makes it possible to develop a supramolecular method for determination of absolute configuration of chiral compounds. The concept, theoretical derivatization, and first demonstration of this daedal noncovalent method using a host-guest system is described. This noncovalent method requires only three substrate solutions and can in principle be applied to any host-guest systems that follow the van't Hoff relation and have a clear anisotropic shielding effect based on a well-defined complex structure regardless of the extent of enantiomer selectivity.     

A Multimicroprocessor-Based Fully Digital AC Drive System for Rolling Mills

Theoretical considerations are given for a control scheme to decrease voltage disturbances in a cycloconverter-fed ac drive system, using a form of the vector control concept. The theory has been applied to a multimicroprocessor-based fully digital 72-arm cycloconverter-fed 5000-kW squirrel-cage induction motor drive control system. For speed and position sensors, a high-resolution sine encoder which generates a 15 000-sine wave/r has been developed to achieve high-performance speed regulation, particularly at ultra-low speeds. The factory test results compare far more favorably than those attainable using dc drives. They reveal that the ac drive system is suited to practical applications in main drives for rolling mills, including tandem cold mills.     

C10-polyacetylenes as allelopathic substances in dominants in early stages of secondary succession

cis-Dehydromatricaria ester (cis-DME) inSolidago altissima, andcis-matricaria ester (cis-ME),trans-matricaria ester (trans-ME), andcis-lachnophyllum ester (cis-LE) inErigeron spp. show strong growth inhibitory effects on other plants. Thecis- andtrans-DMEs were found in soil at the border ofS. altissima communities in concentrations that were inhibitory to test plants. Among four species ofErigeron, the most dominant plant,E floribundus, showed the highest concentrations of the esters. From the results of our experiments, we conclude that these polyacetylenes are probably allelopathic substances with ecological importance.