Materials Literature
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Abstract The effect of temperature on the crystallization of α, β, and γ phases of PVDF from dimethylacetamide (DMA) solution was studied. Variation in the crystallinity content of these three phases was obtained as a function of temperature using infrared spectroscopy, differential scanning calorimetry (DSC) and x‐ra…
A negative isotropic magnetoresistance effect more than three orders of magnitude larger than the typical giant magnetoresistance of some superlattice films has been observed in thin oxide films of perovskite-like La(0.67)Ca(0.33)MnOx. Epitaxial films that are grown on LaAIO(3) substrates by laser ablation and suitabl…
Lactobacillus brevis takes up lactose and the nonmetabolizable lactose analogue thiomethyl beta-galactoside (TMG) by a permease-catalyzed lactose/H+ symport mechanism. Earlier studies have shown that TMG, previously accumulated in L. brevis cells, rapidly effluxes from the cells upon addition of glucose, and that gluc…
We study the effects of relativity on the stability of group II elements Zn, Cd, and Hg in face centered cubic (fcc) and hexagonal close-packed (hcp) structures. A comparison of nonrelativistic and scalar-relativistic results for both the fcc and the hcp phases of these elements, obtained self consistently, clearly sh…
Observation of mode selection in an optical fiber with nematic liquid-crystal cladding is reported. The TE01 mode is guided, while the TM01 mode leaks out. This behavior is achieved by radially oriented liquid-crystal directors in the cladding of an optical fiber with isotropic core. A theory which quantitatively acco…
Abstract The interdiffusion of two miscible polymers, polycarbonate (PC) and a copolyester (KODAR), was studied at temperatures from 200 to 230°C. The two polymers were coextruded as microlayer composites with up to 3713 alternating layers. The microlayer structure provided a large area of intimate contact between the…
Photoluminescence (PL) and Fourier-transform infrared (FTIR) measurements have been performed on light-emitting porous silicon (LEPSi) after annealing at temperatures below 600 °C. Two different kinds of samples with different surface morphologies and different initial concentrations of chemically bonded hydrogen were…
Abstract The crazing behavior of coextruded microlayer sheets consisting of alternating layers of polycarbonate (PC) and styrene–acrylonitrile copolymer (SAN) was investigated as a function of PC and SAN layer thicknesses. In this study, the total sheet thickness remained essentially constant and the PC and SAN layer…
Hydrogen diffusion in ZrH x (1.58<or=x<or=1.98) in the temperature range 600 K to 970 K has been measured by means of pulsed-field-gradient nuclear magnetic resonance. The activation enthalpy for hydrogen diffusion, H a , obtained by fitting an Arrhenius expression D=D 0 exp(-H a /k B T) to the diffusivities, increase…
Abstract The ductility of a calcium carbonate‐filled amorphous copolyester PETG in a uniaxial tensite test was examined as a fiction other filler volume fraction. A ductile‐to‐quasibrittle transition occurred as the volume fraction of filler increased. This transition was from propragation of a stable neck through the…
Abstract Interfacially compatibilized immiscible blends with an isotactic polypropylene matrix (PP) and dispersed polyamide‐66 (PA) were prepared by extrusion with anhydride‐grafted isotactic PP compatibilizers, one of high‐anhydride content (HAC, 2.7 wt % grafted maleic anhydride) and one of low‐anhydride content (LA…
Abstract Two anydride‐grafted isotactic polypropylene (PP) compatibilizers, HAC or high‐anydride compatibilizer (2.7 wt % grafted maleic anhydride) and LAC or low‐anydride compatibilizer (0.2 wt % anydride), were compared in PP‐rich blends with polyamide‐66 (25 wt %). A previous article demonstrated that LAC imparted…
Evidence has recently accumulated that an interconnect under intense electric current can fail by a transgranular slit. A rounded void first forms, enlarges, and drifts. When the void becomes sufficiently large, a narrow slit emerges at the expense of the void, running across the linewidth. In this letter we describe…
Magnetotransport measurements have been carried out on the organic superconductor kappa -(BEDT-TTF) 2 Cu(NCS) 2 at temperatures down to 500 mK and in hydrostatic pressures up to 16.3 kbar. The observation of Shubnikov-de Haas and magnetic breakdown oscillations has allowed the pressure dependences of the area of the c…
We report a revision of the rigid-ion potential for UO 2 introduced by Sindzingre and Gillan (see ibid., vol. 21, p. 4017, 1988). In its original form, the potential is unstable at the reported lattice parameter. We have re-fitted the potential to remove this problem, whilst keeping as close as possible to the origina…
Abstract The effects of various filler characteristics on the ductility of filled amorphous copolyester, Kodar 6763, have been examined. The five fillers in the study included two calcium terephthalates with different particle‐size distributions and three calcium carbonates, also with different particle‐size distribut…
Based on density-functional theory we study the occurrence of a ferroelectric phase in Stockmayer fluids. Because of the long-ranged dipolar forces the corresponding bulk phase diagrams depend on both the shape of the sample and the character of the dielectric surrounding. For ellipsoidal samples with different aspect…
We studied the electro-optical response of a bistable cholesteric texture (BCT) display to ac voltage pulses. The material can be driven into states where planar and focal conic textures coexist at zero field and gray scale memory is achieved. According to the properties of the BCT display we designed two drive scheme…
The luminescence of the alkali halides doped with ns 2 ions is studied in a wide temperature region by the methods of time-resolved polarization spectroscopy with the use of magnetic and electric fields. It is established that the structure and properties of relaxed excited states (RES) of all the centers investigated…
Linked by strings of diphenylhexatriene (DPH) molecules, beta- and gamma-cyclodextrins (CDs) can form nanotube aggregates that contain as many as approximately 20 betaCDs (20 nanometers long) or approximately 20 to 35 gammaCDs (20 to 35 nanometers long). Nanotube formation was indicated in solution, by fluorescence an…