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.     

Friction and wear in silicon nitride-steel and cemented carbide-steel pairs in lubricated sliding

Friction and wear tests between a stationary block and a rotating ring under high contact pressure of about 200 MPa were carried out at room temperature under lubrication with a light mineral oil at a sliding distance of 500 m. The block was silicon nitride and cemented carbide, and the ring was bearing steel. The effect of phosphorus and sulphur contained in the mineral oil on the friction, the roughness of the worn surface and the wear of the steel ring is discussed in relation to both pairs. Sulphur was effective in reducing the coefficient of friction of the cemented carbide block-steel ring pair, while phosphorus was successful in decreasing the wear of the steel ring paired with the silicon nitride block. The surface analysis of the steel ring using X-ray photoelectron spectroscopy (XPS) shows that the peak intensities of sulphur or phosphorus beneath the surface depend upon the material of the counterpart, silicon nitride or cemented carbide blocks.     

Permselectivities of poly(vinyl chloride) membrane for binary alcohol mixtures in pervaporation

Summary Permeation and separation characteristics of binary alcohol mixtures for relatively hydrophobic polymer, poly(vinyl chloride) (PVC), membrane were investigated on pervaporation. In single component measurements, it was found that small-sized alcohol had high solubility and high normalized permeation rate for the PVC membrane. In binary mixture measurements, small-sized alcohol was preferentially incorporated into the PVC membrane in all alcohol mixtures and was predominantly permeated through the membrane. It was found that the solubitity and diffusivity of small-sized alcohol was higher than those of other alcohols in all systems.     

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.     

Theoretical studies of the mechanism of ethylene polymerization reaction catalyzed by diimine-M(II) (M = Ni,Pd and Pt) and Ti- and Zr-chelating alkoxides

We have analyzed the computational results for several elementary reactions of the ethylene polymerization process catalyzed by an alternative (to the existing metallocene catalysts) “non-cyclopentadienyl” catalysts such as diimine-M(II) (where M = Ni and Pd) and chelating bridged Ti- and Zr-complexes. The obtained data have been compared with those for the existing zirconocene-based catalysts. In general, it was shown that: (i) the resting stage of the process is a metal-olefin-alkyl complex, the olefin coordination energy of which is a few kcal/mol larger for diimine-M(II) systems than zirconocene or dialkoxide systems; (ii) the rate-determining barrier is a migratory insertion barrier calculated from the metal-olefin-alkyl complex, which is found to be a few kcal/mol larger for the diimine-M(II) system compared to the Cp₂ZrCH ₃ ⁺ catalyst. The presence of certain flexible bridging ligands X in the Ti-alkoxide complex, [Y(Ph)X(Ph)Y]TiCH ₃ ⁺ , which are capable of donating electron density to the cationic metal center at various stages during the reaction makes this barrier a few kcal/mol smaller for the dialkoxide than the Cp₂ZrCH ₃ ⁺ catalyst. It was shown that an increase in the metal-bridge interaction decreases the migratory insertion barrier and, consequently, increases the catalytic activity of these complexes. Although the diimine-M(II) catalysts are less active than zirconocene-based ones, the microstructure of the polymers produced by the former catalyst, which is found to be a function of temperature, ethylene, steric bulkiness of the auxiliary ligands, and transition metal center, makes them attractive for practice. We also have studied the mechanisms of several chain termination/transfer reactions, as well as the role of steric effects in the studied elementary reactions. We have clearly demonstrated tremendous possibilities of the computational chemistry in solving complex problems of the homogenous catalyst, and its high capability of predicting new and more active catalysts for different commercially important processes including olefin polymerization reactions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Structural characterization of recombinant human erythropoietins by fluorophore-assisted carbohydrate electrophoresis

Two enzyme immunoassay (EIA) systems were compared for their ability to detect Borrelia burgdorferi sensu lato specific IgG and IgM antibodies and to differentiate between symptomatic (83 patients with neuroborreliosis) and asymptomatic seropositive subjects (80 healthy controls). Antibody concentrations were determined by EIA; the antigens used were either a sonicate of B. burgdorferi or three recombinant borrelial proteins: the 14-kDa flagellin fragment, the outer surface protein C (22 kDa) and the high molecular mass protein p83 (83 kDa). In the sonicate, EIA, IgG or IgM antibodies to B. burgdorferi, or both, were detected in all patients with neuroborreliosis and in all controls. Pre-absorption of sera with Treponema phagedenis sonicate diminished the sensitivity of detection of borrelial specific IgG (IgG or IgM or both) antibodies in patients with neuroborreliosis from 80 to 57% (100 to 82%) and in the controls from 100 to 32% (100 to 37%). While being specific for B. burgdorferi, the recombinant EIAs proved to be significantly more sensitive than the sonicate EIA: IgG or IgM, or both antibodies against any of the recombinant antigens were detected in 92% of patients with neuroborreliosis and in 24% of controls. The increase in sensitivity in patients with neuroborreliosis was mostly due to the higher detection rate of IgM antibodies in the recombinant EIA (77% versus 48% in the sonicate EIA), while IgG antibodies were demonstrated with similar frequencies in both EIA systems (57% versus 60%). It was concluded that the recombinant EIAs are superior to the sonicate EIA with pre-absorption of cross-reactive antibodies in the confirmation of an acute borrelial infection and in the differentiation between symptomatic and asymptomatic infections.