Materials Literature
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Abstract A general synthetic route toward symmetric and asymmetric side‐on and end‐on carbazolyl monomers has been developed. The effect of the nature of the core on the induction of liquid‐crystal phases in side‐on carbazolyl polysiloxanes has been studied. Chromophores have been introduced into the carbazole core to…
Solventothermal reaction of certain binary alloys and quaternary alloys with tetraalkylammonium salts in ethylenediamine yielded K6In2Te6·4C2H8N2 and (Ph4P)2In2Te6, respectively. A highly charged dimer, [In2Te6]6-, is observed in the former, while the latter adopts a one-dimensional [In2Te6]2- chain structure in which…
Depending on the operating temperature, gas sensors that are based on n‐type‐semiconductor, polycrystalline gallium oxide (Ga 2 O 3 ) thin films are used to detect oxygen (at temperatures, T, of 850°C) or reducing gases (T 900°C). At high temperatures (T 900°C), beta‐Ga 2 O 3 has an oxygen deficiency in the crystal la…
Mixed phthalocyanines carrying one anthracene (Pc 3 An) or substituted naphthalene nucleus (Pc 3 NcR 2, R = H, OCH 3, or SC 12 H 25 ) are proposed as low-temperature photochroms for spectral hole burning. Solubility of these compounds in polymers was greatly enhanced by introducing the 2,4-dimethyl-3-pentoxy substitue…
Thin films of Ni-Zn ferrite have been epitaxially grown in situ on basal plane sapphires at room temperature by pulsed laser deposition in high vacuum. The films deposited at oxygen pressures of 1×10 -5 to 1×10 -6 Torr grew with spinel-type crystal structure and (111) planar orientation. X-ray phi scan analysis showed…
Hysteresis of the temperature of jumps in the cholesteric pitch in planar layers of cholesteric liquid crystals (CLCs) has been observed in the temperature dependence of the optical transmission spectra measured in a 4.8 ¼ m thick specimen of a 60% chiral racemic mixture of CE6. The temperature difference for the pitc…
The molecular and supramolecular structure of poly( n -hexyl isocyanate) in n -octane has been studied in the sol state and in the gel state by neutron and light scattering. In the sol state the chains appear stiff with dimensional characteristics consistent with the literature on this polymer. The gel consists of a n…
For Na0.5Bi0.5TiO3 single crystals the time dependencies of dielectric and structural properties were investigated. The obtained results reveal that phase transformation in Na0.5Bi0.5TiO3 between tetragonal and rhombohedral symmetries disclosed a time dependent character. This transformation was completed after about…
Caged compounds are molecules whose biological function is masked until UV light induces a photo-chemical reaction that converts the molecules into a biologically active state. These probes provide very powerful tools in cell biology research, since the activation can be precisely controlled temporally and spatially b…
A series of functionalized vinyl cinnamate monomers were synthesized by the reaction of hydroxyethylmethacrylate and various substituted cinnamoyl chlorides. Electron donating and accepting functional groups such as −OCH3, −Cl and −NO2 were introduced at the para position of cinnamoyl chloride. Homopolymerization of t…
Potentiodynamic cyclic anodic polarization, scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) techniques were used to study pitting corrosion behavior of type 904L (UNS N08904) stainless steel (SS) in aerated or argon-deaerated 0.6 M sodium bromide (NaBr) solutions at 25°C. Type 904L SS was shown t…
Hydrogen-free amorphous carbon films with hardness comparable to crystalline superhard materials have been deposited by special pulsed arc techniques. With the combination of very high hardness, high smoothness, and low adhesion activity to other materials which are in contact with them, these films show superior beha…
High-resolution measurements of the molar volume, V, measured as a function of temperature at two different pressures allowed the calculation of the isobaric thermal expansion coefficient, α p ( T ), and isothermal compressibility coefficient, β T ( T ). Critical exponents for observed singularities in both thermodyna…
Abstract The title phthalocyanine (1) was prepared from 3-(pentan-3′-yloxy)phthalonitrile, of which a bulky substituent on the 3-position caused an exclusive formation of 1 out of the possible structural isomers. Complexes of magnesium(II), cobalt(II), nickel(II), copper(II), and zinc(II) were prepared by refluxing a…
The effective thermal conductivity κ of multilayer printed wiring boards (PWBs) has been measured for heat flowing in a direction either parallel (κ∥) or perpendicular (κ⊥) to the plane of the board. The conductivity of the glass/epoxy insulating material from which the boards are manufactured is anisotropic (κ∥ge ≈ 3…
The surface tensions, wetting tensions, contact angles and solid/liquid interfacial tensions of defined siloxanes as well as those of analogous carbosilanes, polysilanes and neopentyl substituted silanes were determined. The wetting experiments were carried out on a glass plate coated with perfluoroalkyl methacrylate…
A new ultraviolet (UV) Raman spectroscopic system to measure the Raman scattering from materials at high temperatures up to 1500 °C has been designed. This system is based on a CW (continuous-wave) ultraviolet argon-ion laser (363.8 nm), a spatial filter, a single monochromator coupled to a double-grating rejection fi…
From a study of the temperature dependence of the dielectric constant of Pb(Zr x Ti1−x >)O3 the ferroelectric transition for 0·515 ≤ x ≤ 0·535 is shown to be discontinuous in nature while it is continuous for x = 0·550. It is proposed that there may be a tricritical point around x = 0·545. The two-phase nature of the…
Reversible phase transitions between the amorphous and the crystalline states have been induced in Sb 0.93 Ge 0.07 thin films by irradiation with picosecond laser pulses of different energy densities. It is shown for the first time that a material can be repetitively cycled between both states by means of ultrashort p…
We have undertaken a comprehensive study of the reaction NH 2 (X 2 B 1 ) + NO → N 2 + H 2 O (1a) and NH 2 (X 2 B 1 ) + NO → N 2 H + OH → N 2 + H + OH (1b). Experimental measurements of the reaction rate coefficient and product branching fraction are combined with accurate ab initio calculations to give a detailed pict…