Materials Literature
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Polyurethane (PU) frequently has been used to manufacture small diameter vascular grafts due to its good bicompatibility. In this study, sponge PU small diameter vascular grafts were fabricated from Pellethane 2103, as well as a self-synthesized PU, by utilization of a salt casting technique and by varying the salt/po…
Dynamic mechanical thermal analysis (DMTA) was used to determine the crosslink density and glass transition temperature of various ceramer coatings. The metal-oxide ceramer coatings were developed using linseed oil as the organic phase with titanium isopropoxide, and zirconium propoxide as the inorganic sol-gel precur…
The eigenmodes of director orientational fluctuations in nematic liquid crystals in confined geometries were studied both theoretically and experimentally by dynamic light-scattering tehnique. The fundamental mode of the orientational fluctuations shows a crossover from bulk behavior, dominated by bulk elastic constan…
Ring-opening polymerization of cyclic dicarbonates, cyclobis(hexamethylene carbonate) (1 a) and cyclobis- (diethylene glycol carbonate) (1 b), and their copolymerization with lactones have been carried out using lipase as catalyst. These carbonates were polymerized by Candida antarctica lipase under mild reaction cond…
The strains determined on polycrystalline materials using X-rays or neutron-rays are averaged values of all those crystallites that, for a given direction of measurement, contribute to the respective interference line. The usual stress evaluation by the sin2ψ-method delivers the mean stress values of the material phas…
Abstract X-ray phase analysis of clays is difficult because these materials generally consist of a mixture of different phases, i.e. , mixed-layer minerals, individual clay minerals (non mixed-layer), and associated minerals, such as calcite and quartz. The analysis requires knowledge that presently is incorporated in…
Geranylgeranyltransferase I (GGTase I) catalyzes the transfer of a prenyl group from geranylgeranyl diphosphate to the carboxy-terminal cysteine of proteins with a motif referred to as a CaaX box (C, cysteine; a, usually aliphatic amino acid; X, usually L). The alpha and beta subunits of GGTase I from Saccharomyces ce…
A series of random copolyesters of reasonably high molecular weight was synthesized with varying composition by melt copolycondensation of dimethyl terephthalate (DMT) with ethylene glycol (EG) and diethylene glycol (DEG). Composition and molecular weight of the copolyesters were determined by 1H NMR spectroscopy and…
The mechanical behavior of plain woven fabric composites under inplane loading is investigated using 3-D finite element analysis (FEA) in conjunction with a micro-mechanical model. The analysis incorporates both geometric and material nonlinearities. The use of finite elements facilitates accurate description of the g…
Farblose Einkristalle von La2(SeO3)3 wurden bei der Zersetzung von La2(SeO4)3 in Gegenwart von NaCl in verschweißten Goldampullen erhalten. Die Verbindung kristallisiert orthorhombisch (Pnma, Z = 4, a = 846,7(1), b = 1428,6(1), c = 710,3(2) pm, Rall = 0,0223). In der Kristallstruktur sind die La3+-Ionen zehnfach von S…
Polyaniline films have been prepared both chemically and electrochemically using formic (‘Pani-Formic’), boric (‘Pani-Boric’) or acetic acid (‘Pani-Acetic’) as protonation media. Among the three, formic acid seems to be a better protonating medium because it selectively yields the conducting phase of polyaniline. The…
A thin film of deuterated poly(methyl methacrylate) (A) and poly(styrene-ran-acrylonitrile) at the critical composition is annealed in the two phase region to induce simultaneous phase separation and wetting of the A-rich phase at the surface. Using forward recoil spectrometry, the wetting layer thickness is found to…
Dielectric studies of the first order phase transition of a ferroelectric liquid crystal material having the phase sequence chiral nematic to smectic C* have been performed using thin (2.5 mum) cells in the frequency range 0.01 Hz to 12 MHz. For planar alignment, one of the cell electrodes was covered with a polymer a…
Copolymers sPS-B consisting of blocks of syndiotactic polystyrene (sPS) and polybutadiene (B) have been prepared using CpTiX3 (Cp = C5H5, X = Cl, F; Cp = C5Me5, X = Me) and TiXn (n = 3, X = acetylacetonate (acac); n = 4, X = O-tert-Bu) activated with methylaluminoxane (MAO). If proper conditions are used, copolymers c…
We synthesized solubilized alkoxysilane-modified perylene derivatives which were covalently attached to an inorganic host matrix, prepared via the sol−gel process. It was shown that the covalent attachment of the alkoxysilane-modified perylenes led to more homogeneous sols and higher concentrations of the dyes in the…
Multiphonon relaxation rates were measured for 13 different energy levels of various rare-earth ions in ${\mathrm{YVO}}_{4}$ single crystals at 77 K. Dependence of the multiphonon relaxation rate on the energy gap that separates each emitting multiplet from the one lying just below it was investigated over the range f…
Nonporous hydrogel microspheres 0.1–1.3 μm in diameter were prepared by the dispersion copolymerization of 1-vinyl-2-pyrrolidone and ethylene dimethacrylate as a crosslinking agent. The crosslinking was evidenced by solid state 13C NMR and elemental analysis. The effect of various parameters including selection of sol…
We have measured the solvation dynamics of a dipolar supercooled liquid near its glass transition in a temperature range in which the average structural relaxation time varies more than four orders of magnitude. The analysis of the time dependent average emission energy and the inhomogeneous linewidth of the S0<--T1(0…
Monolayer-protected nanoclusters exhibit good stabilityboth in solution and dry forms and as such are promising materials for nanocircuits and nanodevices. In this article, an efficient method for fabricating 2D crosslinked nanoparticle networks using the Langmuir–Blodgett technique and dithiols as bifunctional linker…
Alternating oligomers and polymers consisting of 2,2′-bipyridine and diethinylenebenzene units and corresponding model compounds were synthesized and investigated in dilute solutions by absorption spectroscopy and by stationary and time-resolved emission spectroscopy. The strictly linear (rod-like) π-chain oligomers/p…