Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Control over crystal growth by acidic matrix macromolecules is an important process in the formation of many mineralized tissues. Earlier studies on the interactions between acidic macromolecules and carboxylate- and carbonate-containing crystals showed that the proteins recognize a specific stereochemical motif on th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLow-barrier hydrogen bonds and low fractionation factor bases in enzymic reactionsW. W. ClelandCite this: Biochemistry 1992, 31, 2, 317–319Publication Date (Print):January 21, 1992Publication History Published online1 May 2002Published inissue 21 January 1992https://pubs.acs…
The self-consistent theory of the structural, dynamical, and thermodynamic surface properties of anharmonic crystals previously given for one- and two-dimensional models is extended to the surfaces of three-dimensional crystals which take into account the surface anisotropy. After considering the reference system, in…
The temperature dependence of the lattice parameters in the beta -phase (BCC structure) of pure Zr and Zr-2 at.%Co was determined between 900 and 1550 degrees C by neutron diffraction. All diffraction patterns show a high diffuse background, which is identified as thermal diffuse scattering and originates from particu…
A microscopic model of liquid crystals, with frustrated dipolar, van der Waals, and benzene-ring steric hindrance interactions, yields reentrant phase diagrams with the sequence nematic--smectic-${\mathit{A}}_{\mathit{d}--}$nematic--smectic-${\mathit{A}}_{1--}$smectic-C. The Lindemann criterion of melting is adapted t…
We report the first direct measurement of the relaxation of plasma oscillations in a solid. Via the second-harmonic autocorrelation of femtosecond laser pulses, the lifetimes of localized plasma oscillations in silver island films were investigated. Decay times of 40\ifmmode\pm\else\textpm\fi{}7 fs were obtained, whic…
Model colloids composed of two widely separated sizes of poly- styrene spheres are studied at high volume fractions using an optical, multiple-scattering technique. These measurements probe hydrodynamic forces between unlike particles, as well as static, structural predictions made using the Percus-Yevick approximatio…
A reverse mode operation has been achieved in a polymer dispersed liquid crystal (PDLC) film by a novel methodology. A mixture of a dual frequency addressable liquid crystal (crossover frequency (fc): 13 kHz at 298 K), an acryl monomer and an acryl oligomer was irradiated by UV light under the application of an electr…
The third-order nonlinear optical properties of several porphyrin derivatives incorporated in thin films of polymethylmethacrylate have been measured by degenerate four-wave mixing at 598 nm with 1 ps pulses. Both the magnitude and dynamics of the nonlinear response are measured, with each system exhibiting both a sub…
The initial stages of oxidation of the Si(001)-2×1 surface have been studied using scanning tunneling microscopy and spectroscopy. Among the new sites generated by the exposure of this surface to O2 are 1.4 Å high bumps on top of the surface. Upon annealing the O2-exposed surface, or upon O2 exposure at an elevated te…
An investigation of subnanosecond switching of 119-microm radiation achieved by irradiating high-resistivity silicon wafers with 1.7-ns, 337-nm pulses from a nitrogen laser is presented. The experimental results are compared with a one-dimensional numerical multilayer model, which accounts for the generation, recombin…
Amorphous aluminum oxide thin films were prepared on glass and silicon (100) substrates by a low-temperature atmospheric-pressure chemical vapor deposition method. The raw material was aluminum acetylacetonate, which is nontoxic and easy to handle. The substrate temperature could be lowered to 250 °C by the thermal de…
It is demonstrated that photoluminescent porous Si (PS) layers exhibit definitely visible electroluminescence (EL). The PS layers were formed by anodization of single-crystal nondegenerate p-type Si wafers in an HF solution. The experimental EL cells are of the form semitransparent metal/PS layer/p-type Si/Al electrod…
ZnO-SnO2 thin films are deposited by rf sputtering using a sintered oxide target. As-deposited films show different crystal structures of a hexagonal ZnO, a spinel type intermediate compound Zn2SnO4 or an amorphous by experimental conditions. The Zn2SnO4 films show higher than 80% transmissivity over the visible range…
The permanent dipole of the NO 2 radical and the relative displacement between the ions are considered about the ferroelectricity in NaNO 2 . In this case the possibility of the rotation of NO 2 can be explained as the mixed double rotations around the a -axis and the c -axis. The IC phase between the ferroelectric an…
Abstract A stream of unheated crossflow air has been used to make finer melt‐blown fibers. Not only are smaller average fiber diameters obtained, but the variation in fiber diameter is smaller. The use of this technique can allow the production of melt‐blown nonwovens, which have finer fibers and more uniform webs. Si…
The lattice cluster theory is applied to explain the observed strong concentration dependence of the apparent radius of gyration and the correlation length in polystyrene/poly(vinylmethylether) blends. The analysis emphasizes the importance of using a theory that properly describes blend compressibility, monomer molec…
Layered dichalcogenide semiconductors (LS) are studied intensively for photovoltaic applications. It is generally accepted that the smooth van der Waals face (\ensuremath{\perp}c) is most suitable for this purpose. Recombination centers have been associated with surface steps (exposing \ensuremath{\parallel}c facets)…
Ab initio pseudopotential calculations of the crystal structure, electronic structure, cohesive energy, and formation enthalpy of ${\mathrm{B}}_{12}$${\mathrm{As}}_{2}$ have been calculated using a large plane-wave expansion. We compare the bonding with that of ${\mathrm{B}}_{12}$, ${\mathrm{B}}_{13}$${\mathrm{C}}_{2}…
The electron-beam specular reflectivity of an InAs(001) surface was quantitatively measured as current through an electrode at several substrate temperatures. The reflectivity changes discontinuously at the reconstruction transition from As-stable (2\ifmmode\times\else\texttimes\fi{}4) to In-stable (4\ifmmode\times\el…