Materials Literature
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Photoluminescence (PL) measurement has been made on Zn- and Cd-doped p-GaS. The 1.85 and 1.95eV emission bands are observed in the PL spectra of Zn- and Cd-doped samples at 77K, respectively. The shapes of PL spectrum and temperature dependences of full width at half maximum of the 1.85 and 1.95eV emission bands are c…
Ferroelectric copolymer of vinylide0ne fluoride and trifluoroethylene (70/30) was used as an alignment layer in nematic liquid crystal cells. The rubbed ferroelectric polymer films produce excellent planar orientation of liquid crystal molecules. We have found that the ferroelectric polymer film at one of LC cell surf…
The effect of introducing the keto groups into their molecular structure on the physicochemical properties of calamitic liquid crystals is discussed and rationalized in terms of existent theories.
The formation of a supramolecular structure is studied in highly oriented polyethylene samples produced using two different methods based on melt extrusion. Relations between the degree of orientation, structural features, and mechanical properties of oriented samples are established. Zhurkov’s concepts regarding the…
Dimensional stability of tufted carpets has been a continuing problem in the carpet industry for years. When a tufted carpet is installed by the stretch-in method, it experiences stress relaxation over time which can cause the carpet to buckle, wrinkle and become loose with the only option being a costly re-stretching…
We research the possibilities for engineering the morphology of porous structures in n-InP. Lithographic patterning of the sample surface before anodic etching is shown to modify considerably the electric field distribution which, in turn, defines the direction of pore growth inside the specimen. We show that local fo…
Dielectric flashover along insulators in vacuum has been sufficiently researched in the past. Less studied, but of similar importance, is surface flashover at atmospheric pressures and the impact of various electrode geometries, humidity, and type of gas present. Previous research has shown distinct arc behavior in ai…
The total linear attenuation coefficients micro (cm(-1)) have been obtained using the XCOM program at photon energies of 1 keV to 1 GeV for six different natural marbles produced in different places in Turkey. The individual contribution of photon interaction processes to the total linear attenuation coefficients for…
Recent performance and reliability upgrades to the dual axis radiographic hydrodynamic test (DARHT) facility second axis induction cells have impacted various cell mechanical components. To attain a higher level of performance and reliability, key mechanical elements comprising the induction cells were redesigned. The…
Abstract Mn-, LaMn- and LaCaMn-citrates were synthesized at 60–120°C in ethylene glycol medium using chlorides or nitrates as metal sources. Their composition, IR spectra and thermal decomposition were studied. Equimolar La/Mn ratio has been established in the complex, prepared from chloride solution with the same ini…
Chlorin-α-diones and tetraones are useful intermediates for the formation of porphyrin arrays. We have developed a simple three-step route to chlorin-α-diones and tetraones. It was found that meso-tetraarylchlorins could be converted to hydroxychlorins when adsorbed on silica. The hydroxychlorins could then be oxidize…
Microcellular foamed plastics by injection molder draw attraction due to light weight, less warp, reduced cycle time, less sink mark, and so on, because of cells nucleated in the polymer matrix during the injection. Although foamed plastics by injection molder have many merits as listed above, there are few studies wh…
On performing an in-situ UV-polymerization of tri-acrylate in 5CB nematic samples, we observe the formation of a film onto the cell plates that is able to record virtual disclination lines. This memory effect evidences that the director orientation is imprinted onto the substrates during the polymerization process. In…
Dielectric and DSC methods were used to study liquid crystalline compound MHPNBC exhibiting para-, ferro-, ferri-, antiferroelectric and a highly ordered antiferroelectric like phase. Two dielectric relaxation processes were revealed in the ferroelectric phase: typical Goldstone mode in the whole temperature range and…
Dielectric, ferroelectric, antiferroelectric and magnetic properties of the PbB3+ 2/3B6+ 1/3O3 perovskites are reviewed. One of peculiarities of these perovskites is a frequent presence of the Fe3+, Mn3+ etc among the B3+ ions. The main peculiarity is ordering of the B3+ and B6+ ions in the octahedral positions of the…
ZSM-5 catalysts containing either Cu or Co cations individually or Cu/Ca or Co/Ca cation combinations were prepared by ion exchange. These materials were tested as catalysts for the reduction of NO to N2 in the presence of propane or methane. Cu2+ and [Cu-O-Cu]2+ species were identified in ion exchangeable sites in th…
In the present work, the mechanical behavior of stress corrosion cracking phenomenon is described. Such phenomenon presents strong complexity due to metallurgic and electrochemical aspects. A methodology for modeling both SSR (Slow Strain Rate) and CL (Constant Load) tests based upon thermodynamics of continuum solids…
Copper-doped SrTiO/sub 3/ (STO) powders were processed by conventional bulk preparation techniques to establish solubility limits of Cu in STO. The maximum solubility of Cu in STO was identified to be /spl sim/1%. Epitaxial Cu-doped SrTiO/sub 3/ (STO) buffer layers were then prepared by pulsed laser deposition (PLD) a…
The helical structure of the chiral nematic phases induced by chiral dopants in nematic solvents provides macroscopic information about the molecular chirality of the dopant. The surface model, which combines the order parameters of the dopant in nematic host phase and chirality parameters of the dopant, is a simple m…
M-Si-Al-O-N glasses (where M = Y or rare earth cation) are intergranular phases in silicon nitride based ceramics in which the composition and volume fraction of these oxynitride glass phases determine the properties of the material, in particular, high temperature mechanical behaviour. Investigations on oxynitride gl…