Development of fully-automated synthesis systems

This paper describes the development of fully-automated synthesis systems for preparing and isolating various kinds of pharmaceutical compounds. The systems are versatile, and are able to perform most of the chemical reactions currently used in organic chemistry, with the exception of hydrogenation which requires high pressure. An additional benefit is the very user-friendly software.     

Processing-Dependent Microstructural Factors Affecting Cavitation Damage and Tensile Ductility in a Superplastic Alumina Dispersed with Zirconia

Superplastic tensile ductility in Al₂O₃–10 vol% ZrO₂ (3 mol% Y₂O₃) exhibits processing dependence when the grain size is reduced to 0.45 μm for a given relative density of ∼99.5%. The reduced grain size leads to largely enhanced ductility in a material prepared by colloidal processing, but does not in a material prepared by conventional dry processing. This result is explained from cavity-damage accumulation sensitive to a rather small variation in a few processing-dependent factors: the numerical densities of residual defects and ZrO₂ particles. The rate of damage accumulation is shown to depend mainly on the former and additionally on the latter.     

Alkaline Activation of Blends of Metakaolin and Calcium Aluminate

The present paper reports the preliminary results obtained and analyzed in the framework of a joint Spanish–Japanese project on the behavior of blends of alkali-activated metakaolin (MK) and calcium aluminate cement (CAC). In these experiments, the materials were activated with an 8 M solution of NaOH, poured into molds, and subjected to brief thermal curing (2 or 20 h at 85°C). The hardened pastes were tested for mechanical strength and characterized for mineralogy and microstructure by a number of techniques (XRD, FTIR, BSEM, and MAS-NMR). The results showed that under the above conditions, the Al and Ca in the CAC were taken up into the aluminosilicate formed as the main product of the alkali activation of MK. None of the CAC hydration compounds (CAH₁₀; C₂AH₈; C₃AH₆; AH₃) normally formed were detected in any of the cases studied.     

Composition measurement of paraelectric SrTiO3 layer

Abstract

Since composition is an important parameter affecting the dielectric properties in paraelectric SrTiO₃ layers, composition is determined by Rutherford backscattering spectrometry (RBS) measurement. In this measurement, specifically for achieving precise composition measurement, the RBS spectra of Sr, Ti and O must be separated individually. This spectrum separation can only be attained when thin (800 A[ddot] thick) Sr_xTiO_y layers are deposited on graphite substrate. The measurement is performed for layers deposited at different O₂ partial pressure ratios and sputtering pressures. This measurement indicates that composition of O, y, in Sr_xTiO_y layer decreases from 3.7 to 2.7 with the decrease of O₂ partial pressure raito, R(=O₂/O₂ + Ar) from 1.0 to 0.83. Composition of Sr, x, also changes from 1.1 to 0.6 with this change. With the decrease of sputtering pressure from 10 to 5 mTorr, however, composition, y, is held at 2.7 and only the composition, x, increases from 0.6 to 1.1. This composition measurement is useful for the deposition of optimized dielectric layer employed in the charge storage capacitor.     

Enhanced thermal conductivity of semi‐aliphatic liquid crystalline polybenzoxazoles using magnetic orientation

Polybenzoxazole (PBO) model compounds consisting of benzoxazole mesogenic units linked with long alkyl chains via ether or ester groups were prepared from flexible dicarboxylic acids with two kinds of bis(o‐aminophenol)s, i.e. 4,4′‐diamino‐3,3′‐dihydroxybiphenyl (p‐HAB) and 3,3′‐diamino‐4,4′‐dihydroxybiphenyl (m‐HAB). The results revealed that the use of p‐HAB completely erased the thermotropic liquid crystallinity and that the m‐HAB‐based ether‐linked model compound was much more advantageous for the formation of a stable liquid crystal phase than the corresponding ester‐linked one. However, the relevant high‐molecular‐weight PBOs showed quite opposite results. Only the m‐HAB‐based ester‐linked C₁₀ PBO system showed a liquid crystal‐like texture among various semi‐aliphatic PBO systems examined. A very high thermal conductivity of 1.79 W m^?1 K^?1 along the thickness direction for the m‐HAB‐based ester‐linked C₁₀ PBO film was achieved by heat treatment in the liquid crystalline state under a strong magnetic field of 10 T. Copyright © 2011 Society of Chemical Industry     

Thermostabilization by replacement of specific residues with lysine in a Bacillus alkaline cellulase: building a structural model and implications of newly formed double intrahelical salt bridges

An alkaline, mesophilic endo-1,4-ß-glucanase fromalkaliphilic Bacillus sp. strain KSM-64 was significantly thermostabilizedby replacement of both Asn179 and Asp194 with lysine by site-directedmutagenesis. Structural remodeling of the mutant enzyme newlygenerated by the double mutation suggested that Glu175     

Preparation of poly(2-pyridone-3,5-diyl)s with –(CH2)4–SO3M (M = H or Na) side chains

Poly(2-pyridone-3,5-diyl)s with –(CH₂)₄–SO₃M (M = H or Na) side chains have been prepared by nickel-complex promoted dehalogenative polycondensation. A composite film of the polymer with –(CH₂)₄–SO₃H side chains and poly(vinyl alcohol) showed a proton conductivity of 1.5 × 10^?1 S cm^?1 at 80 °C and 95% humidity. A copolymer with pyridine showed a high stability against oxidation by a Fenton reagent.     

Fabrication of translucent AlN ceramics with MgF2 additive by spark plasma sintering

Translucent AlN ceramics with 0‐2 wt.% MgF₂ additive were prepared by spark plasma sintering. AlN powder was heated temporarily up to 2000°C, before holding at 1850°C for 20 minutes in N₂ gas. The sintered ceramics consisted of a single phase of hexagonal AlN, and showed a transgranular fracture mode. The total transmittance was improved remarkably by the additive, to reach 74% at a wavelength of 800 nm for 1 wt.% MgF₂. For 2 wt.% MgF₂, the transmittance was slightly lower than that for 1 wt.% MgF₂, and an absorption band was observed apparently at around 400 nm. The addition of MgF₂ along with the temporary heating at higher temperatures than the sintering temperature contributed to improve the transmittance remarkably.