Materials Literature
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Dc electrical conductivities [sgrave]dc of 90V2O5−10Bi2O3 (VB) glasses doped with different SrTiO3 concentrations (0–40 wt%) are reported between 80 and 450 K. At higher temperatures, the Mott model of phonon-assisted small-polaron hopping between nearest neighbours is consistent with the conductivity data while, at l…
Technical Briefs Nucleate Pool Boiling on Micro Graphite–Copper Composite Surfaces Gai-Wai Yang, Gai-Wai Yang Department of Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, MI 48109 Search for other works by this author on: This Site PubMed Google Scholar Hsing-Sheng Liang, Hsing-Sheng…
BACKGROUND/AIMS: Monitoring of ultraviolet (UV) exposure in humans is important, since UV has been implicated in the pathogenesis of skin cancer, skin ageing and immunosuppression. Biological and physical dosimeters are being developed to measure occupational and environmental UV radiation exposure. We studied the UV-…
The segmented poly(urethane urea) copolymers were synthesized by one- and two-step polymerization procedures. The copolymers were based on 4,4′-diphenylmethane diisocyanate, 3,5-diethyltoluene diamine, and ethylene oxide-capped poly(propylene oxide) diol. The mean sequence lengths of polyurethane soft block and polyur…
The structure of Sb 2 WO 6 [ M r = 523.4, triclinic, F {\bar 1}, a = 11.132 (1), b = 9.896 (4), c = 18.482 (7) Å, α = 90.20 (4), β 96.87 (8), γ = 90.21 (5)°, D x = 6.88 g cm −3 , Z = 16, Mo K α, λ = 0.7107 Å, μ = 338.5 cm −1 , F (000) = 3536] has been refined as an enlarged 2 a × 2 b × 2 c F -centred superstructure of…
In cholesteric liquid crystals with positive dielectric anisotropy an electric-field induced texture with unusual properties was observed. This texture appears after the reduction of the electric field during the transition from the homeotropic nematic state into the planar cholesteric one. The angular and the electri…
Abstract The band structure and magnetic properties of the ordered Co 2−x Ni x TiSn Heusler‐type alloys for x = 0, 1, and 2, are studied by using the spin‐polarised TB LMTO method. We found that the Ni 2 TiSn system is paramagnetic. The self‐consistent band calculations for the systems with vacancy (□) have shown that…
The formation of dislocation rings at crack tips is considered when the glide plane is tilted against the crack plane and does not contain the crack front. The emanating ring is described in the Peierls model by a distribution of infinitesimal dislocations and the influence of the interplanar potential in the glide pl…
Shear viscosity of molecular liquids is formulated and calculated with use of a time-dependent density-functional theory. Allowing for nonrigidity of each molecule, we obtain shear-induced distortion of both intramolecular and intermolecular correlations self-consistently, which makes it possible to calculate the shea…
Abstract Novel alternating conjugated copolymers were prepared by electrochemical polymerization of defined bis(1‐methylpyrrol‐2‐yl)arenes. The comonomers were synthesized by the nickel‐catalyzed coupling reaction (Kumada synthesis) of 1‐methylpyrrol‐2‐yl anion with various dibromoarenes. The monomers were characteriz…
Stress corrosion cracking (SCC) characteristics of three commercially available nickel-molybdenum alloys (designated B, B2, and B3 [UNS N10001, N10667, and N10675, respectively]) in a reducing environment were investigated, with the alloys in their mill-annealed (MA) state and after heat treatment (HT) to simulate eff…
The proposed multilayer technology makes it possible to approximate a continuous phase distribution by discrete phase steps. Compared with binary techniques, a higher diffraction efficiency can be achieved. In most known processes a bulk substrate is used and etched directly; therefore it is difficult to control the h…
Abstract Shortly after construction of a subdivision in the southwest Denver metropolitan area in 1986, a portion of the subdivision built directly on steeply-dipping strata of the Pierre Shale began experiencing damaging differential movements, causing house foundations to fail and pavements to warp and crack. This f…
The adhesive properties of various siloxane modified polyimides were studied for the development of suitable adhesive materials with good thermal stability. Their adhesive properties were influenced by siloxane content in the polymer backbone and the structure of the aromatic component. Among them, the copolyimides wi…
The stress-stress correlation function and the viscosity of a united-atom model of liquid decane are studied by equilibrium molecular dynamics simulation using two different formalisms for the stress tensor: the atomic and the molecular formalisms. The atomic and molecular correlation functions show dramatic differenc…
The dielectric permittivity and losses of PVC stabilized with cadmium laurate were measured in the temperature range 300–400 K and frequency range 1 kHz-1 MHz. The relaxation behaviour was found to obey the Williams–Landel–Ferry (WLF) equation. The observed activation energy was 1.1 eV which is in fair agreement with…
The monophosphate tungsten bronzes with pentagonal tunnels (MPTBp) of general formula (PO2)4(WO3)2m form a family of layered conductors where the average number of conduction electrons per tungsten atom 2/m can be changed while keeping the same structural array. Previous investigation of the low m=4,6 and 7 members of…
Corrosion in oil/water systems in the oil industry continues to be a major problem that has not been adequately addressed. This article describes, in a qualitative manner, the mechanisms involved in three well-defined regions of behavior with an emphasis on region 1, which is the most important in predicting the onset…
The time dependence of the complex dielectric permittivity of lead magnoniobate (PMN) single crystal in an applied external DC field, was studied. The field was applied in a “zero-field-cooling” regime. All measurements were carried out for the low-temperature PMN non-ergodic glassy phase. The transition to the polar…
Abstract Grafting of polypropylene was carried out in both boiling xylene and decalin as solvent medium with itaconic acid (2‐methylenesuccinic acid) as functional polar monomer using 2,5‐dimethyl‐2,5‐bis( tert ‐butylperoxy)hexane (Lupersol 101) as radical initiator. It was found that the temperature influenced the pe…