Materials Literature
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The low value of , where is the nematic-isotropic phase transition temperature and denotes the virtual transition temperature, is a long-standing puzzle in the physics of liquid crystals. The present review presents experimental and theoretical results on this long-standing problem. New experimental and theoretical re…
<div class="htmlview paragraph">Many studies suggest that lean-NO<sub>x</sub> SCR proceeds via oxidation of NO to NO<sub>2</sub> by oxygen, followed by the reaction of the NO<sub>2</sub> with hydrocarbons. On catalysts that are not very effective in catalyzing the equilibratio…
The dielectric response of epitaxial BaTiO3 thin films deposited on MgO was measured through surface electrodes as a function of applied bias, frequency, and temperature. The room temperature value of the dielectric constant was ∼500 with a dissipation factor, tan(δ), of 0.05 at 100 kHz. Measurements varying the bias…
An alternative approach to the synthesis of mono-sized and parallel-aligned single-wall carbon nanotubes (SWCNs) is reported. The SWCNs are formed in 0.73 nm sized channels of microporous aluminophosphate crystallites by pyrolysis of tripropylamine molecules in the channels. They are characterized through transmission…
Applying a Keldysh Green`s function method it is shown that hot electrons injected from a STM-tip into a CoSi${}_2$/Si(111) system form a highly focused beam due to the silicide band structure. This explains the atomic resolution obtained in recent Ballistic Electron Emission Microscopy (BEEM) experiments. Localized s…
We observe that the temperature coefficients of electron-hole pair energies $(dE/dT)$ in PbS and PbSe quantum dots depend strongly on the size of the quantum dot. With decreasing size the temperature coefficient of the lowest electron-hole pair energy ${\mathrm{dE}}_{g}/dT$ decreases by more than an order of magnitude…
Adhesion properties between branched polyethylene (PE) and isotactic polypropylene (PP) were studied by a peel test and scanning electron microscopy. In this study, two types of branched PEs were used; one is a linear low density polyethylene (LLDPE) and the other is a high pressure low density polyethylene (LDPE). Th…
Polymer-based positive temperature coefficient (PTC) composites are of special interest because they have great potential in temperature-sensitive devices. To obtain a reproducible PTC composite with acceptable PTC intensity, effect of conductive filler content, processing conditions and filler treatment with nitric a…
Titanate whisker-reinforced polypropylene composites were prepared in a twin-screw extruder followed by injection molding. The whiskers were surface treated with tetrabutyl orthotitanate prior to blending. The static and dynamic mechanical properties, impact strength, and thermal properties of the composites were inve…
Poly(ester urethane ureas) (PesURUs) and poly(ether urethane ureas) (PetURUs) synthesized from diphenylmethane-4,4′-diisocyanate and poly(butylene adipate) diol, and poly(tetramethylene oxide) diol or poly(propylene oxide) diol, respectively, were hydrolyzed at 70°C for various periods up to 16 weeks. Differences in t…
Volume and enthalpy relaxation in glassy materials subjected to a temperature jump Δ T = T 0 − T can conveniently be compared on the basis of the fictive relaxation rate R f = −(d T f /d log t ) i . It has been shown that within the current phenomenological model, involving the stretched exponential relaxation functio…
Three new tin(II) oxalate materials, of which one has an open-framework layered structure, have been synthesized hydrothermally in the presence of structure-directing organic amines. Crystal data: oxalate 1, [(CH 3 ) 2 NH(CH 2 ) 4 NH(CH 3 ) 2 ] 2+ [Sn 2 (C 2 O 4 ) 3 ] 2 -, monoclinic, space group P 2 1 / c (No. 14) a…
The mechanical properties and phase microstructure of ternary phase polypropylene composites have been investigated using combinations of rigid glass beads and ethylene/propylene rubber (EPR) modifiers. Particular consideration has been given to the relative interaction between these components and their dispersion wi…
The surfaces of calcium hydroxyapatite (CaHAP) particles with different Ca/P atomic ratios, synthesized by the precipitation method, were characterized and the adsorption mechanism of CO 2 on CaHAP at 25 °C was elucidated mainly by FTIR. The number of surface P−OH groups was maximum at Ca/P = 1.6 while the quantity of…
This paper presents a new class of nonlinear optical (NLO) polyimide for second harmonic generation (SHG). This new class of NLO polyimide consists of 2,4-diamino-4‘-nitroazobenzene (2R-DIAMINE) with 3,3‘4,4‘-benzophenonetetracarboxylic dianhydride, in which the NLO dipole moment is aligned transverse to the main chai…
The largest isopolyoxotunstate ion known to date, W24O8424− (structure shown in the picture), isolated as the cesium salt, and a chainlike polyoxotungstate ion made up of planar W4O16 units, isolated as the sodium salt, hide behind the simple empirical formulas of the title compounds.
Samples of poly(ethylene-iso/terephthalate)-perfluoro polyether multiblock copolymers with perfluoropolyether (PFPE) segments of different lengths have been characterized for surface composition by XPS and angular dependent XPS in order to determine the influence of the length of the PFPE blocks on the surface segrega…
Vacuum-ultraviolet (VUV) radiation causes the dissociation of organic σ bonds such as the C−C and the C−H bonds in polyolefins. The radicals formed in this process were investigated by trapping with nitric oxide. PE, PP, and PS were irradiated in ultrahigh vacuum with the MgF 2 -filtered radiation of a hydrogen plasma…
A significant extension of the class of AgSe clusters is achieved with the synthesis of the title compounds. This confirms the concept that attaching organic ligands to the outer surface of the cluster hinders the formation of stable binary selenides. The protecting phosphane ligands have a great influence on the stru…
The lactose permease, encoded by the lacY gene of Escherichia coli, is an integral membrane protein that functions as a proton and lactose symporter. In this study, we have characterized a novel monodisperse, purified preparation of lactose permease, as well as functionally reconstituted lactose permease, using spectr…