Preparation of polydimethylsiloxane/polystyrene interpenetrating polymer network membranes and permeation of aqueous ethanol solutions through the membranes by pervaporation

Polydimethylsiloxane (PDMS)/polystyrene (PSt) interpenetrating polymer network (IPN) membranes were prepared by the bulk copolymerization of styrene and divinylbenzene in the PDMS networks. The interpenetration of PDMS and PSt resulted in the improvement of mechanical properties of PDMS. Transmission electron microscope (TEM) observation demonstrated that the PDMS/PSt IPN membranes have microphase-separated structures consisting of a continuous PDMS phase and a discontinuous PSt phase. When an aqueous ethanol solution was permeated through the PDMS/PSt IPN membranes by pervaporation, the PDMS/PSt IPN membranes exhibited ethanol permselectivity, regardless of the PDMS content. The effects of their microphase-separated structures on the permeability and selectivity for aqueous ethanol solutions are discussed experimentally and theoretically. © 1996 John Wiley & Sons, Inc.     

Low loss fibre transmission of high speed pulse signals at 1.29 ?m wavelength

Using InGaAsP semiconductors laser emitting at 1.29 ?m wavelength as optical sources, and low-loss germanium-doped single-mode silica fibres with 11 km lengths, optical transmission experiments were carried out at 400 and 800 Mb/s bit rates.     

Signature-check based unification filter

Among the different processes that entail unification-based grammar parsing, the unification of feature structures is by far the most expensive one in terms of execution time. Unification of the feature structures of a given sentence typically takes between 85 and 98 per cent of the total elapsed time during parsing, thus the need to develop faster unification methods. The approach presented in this paper is based on the fact that, in general, between 60 and 85 per cent of unifications attempted in a typical parse result in failure. Our claim is that the efficient treatment of such unification failures reduces unification time significantly. In this paper we present what we call a unification filter or U-filter, that preprocesses the feature structures to be unified. If the U-filter succeeds, unification is then skipped because the attempt to unify the involved structures would result in failure. On the other hand, when the U-filter does not succeed it is not possible to determine at that moment whether or not the structures unify, so unification is performed. The U-filter stops around 87 per cent of unification failures, and speeds up unification time by an average of around 29 per cent over quasi-destructive graph unification, the fastest unification method known so far.     

Stabilisation in bacillus stearothermophilus of a recombinant plasmid carrying the homologous α-amylase gene

The phenotypic stability of the recombinant plasmid pAT9 (11.5 MD), which contained the cloned α-amylase gene from B. stearothermophilus, was studied in batch and continuous culture. Irrespective of the type of culture (batch or continuous; or using glucose or maltose as carbon source), deletion plasmids of the phenotype Km^rAmy^? the same size (7.3 MD) emerged with time. DNA sequencing analysis and Southern hybridization of a region adjacent to both ends of the pAT9 HindIII fragment containing the α-amylase gene showed that almost the entire part of the HindIII fragment was lost. Homology between fragments contiguous to the pAT9 HindIII terminals allowed exclusion of a fragment that did not encode the α-amylase gene and a new recombinant plasmid, pATHP9 (Km^rAmy⁺; 7.5 MD), was constructed which had enhanced phenotypic stability in B. stearothermophilus.     

Homogeneous palladium catalyst for the oxidative carbonylation of bisphenol A to polycarbonate in propylene carbonate

Polycarbonates (PCs) were prepared in a propylene carbonate solvent by the oxidative carbonylation of bisphenol A with Pd/bithienyl complexes, Pd/bipyridyl complexes, and Pd C σ-bonded complexes for comparison as homogeneous Pd catalysts. With the Pd/bipyridyl complexes, the 6,6′-disubstituted 2,2′-bipyridyl ligand showed a stronger substituent effect than the 2,2′-bipyridyl ligand, which lacked substituents at the 6,6′ positions. With the Pd/bithienyl complexes, however, the substituent effect was not seen. The Pd/bithienyl complexes, which lacked substituents at the 5,5′ positions, gave a PC yield that was the same as the yield of those that had substituents at the 5,5′ positions. The combination of the Pd C σ-bonded complexes and an inorganoredox cocatalyst showed a PC polymerization behavior that was different from the other two types of complexes. When Co(OAc)₂·4H₂O was used as the inorganoredox cocatalyst, all of the Pd C σ-bonded complexes gave a good PC yield. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Application of Super High Definition Images in Telemedicine: System Requirements and Technologies for Teleradiology and Telepathology

It was recognized early on that the digitization of medical information would advance the efficiency of diagnostic technology. However, the digitization of image data, which makes up the majority of medical information, is dependent on advances in technologies such as input, processing, transmission, storage, and display. Insufficient advances in such technologies has effectively limited the digitization of image data for medical use. The result of this has been non-networked systems or LANs confined to a single hospital. Such isolated systems integrate only portions of digital medical images such as x-ray computer tomography (CT), magnetic resonance (MR), and computed radiography (CR).Fortunately, recent advances in the areas of super high definition image I/O, high-quality encoding, super high speed transmission, and high-capacity storage has turned the tide in favor of the digitization and networking of all medical information. This paper will focus on the digitization and networking of medical image information used within hospitals and provide a multifaceted study of the technologies necessary for these advances. This will allow us to discuss the present state of related technical developments and the level that has been attained so far. In addition, we have targeted image information that demands the highest level of quality (radiological and pathological images) for application in medical diagnosis using super high definition images, the image technology being developed by the authors of this paper. We will cover the concrete issues and approaches to solutions that must be investigated when building and networking a digital system.     

Electroluminescence properties of PbTe pn junctions fabricated under controlled Te vapor pressures

Electroluminescence properties of PbTe pn junctions grown under various tellurium vapor pressures are investigated. For unintentionally doped pn junctions, the luminescence bands corresponding to D-A pair and band to band transition are observed. The luminescence intensity of the band to band transition has depended on tellurium vapor pressure, which suggests nonradiative transitions through nonstoichiometric defects forming deep levels. For pn junctions with Bi-doped epitaxial layers, only one peak appears at 20∼25 meV below band to band-transition energy, which, probably, shows recombination through impurity levels or impurity band originating from Bi-doping.     

Synthesis and Superconducting Properties of Layered Ruthenocuprates

Superconducting properties of layered ruthenocuprates, RuSr ₂ RECu ₂ O ₈ and RuSr ₂ (RE _1-x Ce _x ) ₂ Cu ₂ O ₁₀ (RE = Sm, Eu, Gd), are investigated. The differences between superconductivity of these two phases are considered to be due to, their structural differences ; The RE/Sr substitution is more feasible in RuSr ₂ RECu ₂ O ₈ than in RuSr ₂ (RE _1-x Ce _x ) ₂ Cu ₂ O ₁₀ , while the latter phase shows larger oxygen nonstoichiometry. The superconducting RuSr ₂ Eu ₂ Cu ₂ O ₈ (T _{c, onset} = 25K, T _{c, zero} = 7K) phase was successfully synthesized for the first time, and coexistence of superconductivity and ferromagnetism in these systems was reconfirmed by using single-phase samples.