Materials Literature
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Mesoporous silica with silver (Ag) nanoparticles within its pores was synthesized by thermal decomposition of silver nitrate. The structure of this new material was examined by x-ray diffraction, transmission electron microscope and Brunauer - Emmett - Teller techniques, and its optical absorption spectra were measure…
The properties of InAs (110) surfaces have been investigated by means of low-temperature scanning tunneling microscopy and spectroscopy. A technique for ex-situ sulphur passivation has been developed to form an accumulation layer on such a surface. Tunneling spectroscopy at 4.2 K shows the presence of 2D subbands in t…
The low-field magnetoresistance (MR) properties of polycrystalline La0.67Sr0.33MnO3 and La0.67CaO33MnO3 thin films with different grain sizes have been investigated and compared with epitaxial films. MR as high as 15% has been observed in the polycrystalline films at a field of 1500 Oe at low temperatures, whereas the…
An n-type semiconducting diamond thin film was obtained by microwave enhanced plasma chemical vapor deposition using phosphine (PH3) as a dopant source. A homoepitaxial diamond thin film with a thickness of about 300 nm was grown on the {111} surface of a type Ib diamond with a variety of dopant concentrations. Over a…
We have calculated the viscosities of a biaxial nematic liquid crystal phase of a variant of the Gay–Berne fluid [J. G. Gay and B. J. Berne, J. Chem. Phys. 74, 3316 (1981)] by performing molecular dynamics simulations. The equations of motion have been augmented by a director constraint torque that fixes the orientati…
To enhance the water absorbency of wood fibers, various acrylic monomers were grafted to these fibers using cerium IV initiation followed by base hydrolysis. The absorbent capacity of hydrolyzed methyl acrylate- or acrylonitrile-grafted wood pulp fibers was an order of magnitude greater than ungrafted pulp fibers. A p…
Ab initio self-consistent-field (SCF), two-configuration SCF (TCSCF), and density functional theory (DFT) calculations on the charge–transfer complexes of doubly Li/Cl-doped oligothiophenes and oligo(p-phenyls) and on respective charged systems without counterions have been carried out in order to study polaron to bip…
A study of the mechanical properties in an accelerated service-related environment of recycled glass-fiber-reinforced polyamide 66 is reported. Material reinforced with 30 wt % of short fibers was reground and remolded up to seven times. Thermal aging in air at 140°C for up to 3000 h and coolant aging at 110°C for up…
Six kinds of regioselectively substituted cellulose heteroesters (cellulose propanoate diacetate, cellulose butanoate diacetate, cellulose acetate dipropanoate, cellulose butanoate dipropanoate, cellulose acetate dibutanoate, and cellulose propanoate dibutanoate) and three kinds of cellulose triesters (cellulose triac…
The reaction of carboxylic acid anhydride with poly(vinyl alcohol) (PVA) leads to vinyl alcohol—vinyl ester copolymers which contain carboxylic acid groups. Esterification enables degrees of modification to be reached which depend on the chemical structure of the anhydride introduced and the ratio of the reagents in t…
Reactions of laser-ablated Cr atoms with O2 gave a very strong, sharp 965.4 cm−1 band and weak, sharp 1869.7, 984.3, 914.4, 846.3, 716.2, and 643.1 cm−1 bands. The 1869.7, 965.4, and 914.4 cm−1 bands track together on annealing, show 52Cr, 53Cr, 54Cr isotopic splittings appropriate for a single Cr atom and triplets wi…
This article addresses the effect of thermal aging on unreinforced and glass-reinforced recycled polyamide 66. As an accelerated test, injection-molded test bars were aged at 110, 140, and 170°C for up to 4000 h in air to simulate service life. FTIR spectroscopy demonstrated that the oxidative degradation primarily oc…
We have found that the chemistries of inner and external coagulants, gelation bath temperature, and air gap distance have profound effects on 6FDA-polyimde hollow-fiber morphology and performance. This 6FDA-polyimide is made of 50 mol % 2,2′-bis(3,4′-dicarboxyphenyl) hexafluoro propane dianhydride (6FDA) and 50 mol %…
Single - molecule fluorescence spectroscopy of a multichromophoric conjugated polymer (molecular weight ∼20,000) revealed surprising single-step photobleaching kinetics and acute jumps in fluorescence intensity. These jumps were shown not to result from spectral diffusion and were attributed to fluctuations in the qua…
We present a new integral equation formulation of the polarizable continuum model (PCM) which allows one to treat in a single approach dielectrics of different nature: standard isotropic liquids, intrinsically anisotropic medialike liquid crystals and solid matrices, or ionic solutions. The present work shows that int…
Nucleation and its mechanism of diamond on titanium substrates under very low pressure was studied using hot-filament chemical vapor deposition. Very high nucleation rates and densities (10^8-10^{10} cm^{-2}) were obtained under 1 torr, which were 1-3 orders of magnitude higher than the counterpart (10^7 cm^{-2}) unde…
Absorption and fluorescence spectra of Nd3 +were measured in potassium tantalum gallate, lead bismuth gallate (PBG), fluorozirconate (ZBLAN), and Ge-Ga-S glasses. A Judd -Ofelt analysis was performed to determine the spontaneous emission probability and stimulated emission cross section of the4 F3/2 ?4 I11/2 transitio…
Diamond nucleation under very low pressure (0.1-1.0 torr) was obtained at very high nucleation densities and very rapid rates using hot-filament chemical vapor deposition (HFCVD). The density on mirror-polished silicon was as high as 10^10 - 10^11 cm^{-2}, equivalent to the highest density in a microwave-plasma CVD sy…
The electrical resistivity of liquid hydrogen has been measured at the high dynamic pressures, densities and temperatures that can be achieved with a reverberating shock wave. The resulting data are most naturally interpreted in terms of a continuous transition from a semiconducting to a metallic, largely diatomic flu…
The first non-empirical computation of lattice thermal conductivity has been performed for MgO using molecular dynamics (MD), a non-empirical ionic model (the Variationally Induced Breathing (VIB) model), and Green-Kubo theory. The computation is first-principles in the sense that no parameters are fit to experiment.…