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。
In order to explain the positive temperature coefficient of the visible index of refraction of fused silica I develop a simple model which assumes a single ultraviolet resonance. Assuming thermal broadening and using the Kramers- Kronig relations leads to a temperature coefficient in qualitative, but not quantitative,…
We report that a rapid drop of pressure applied to a melt whose crystallization point is a decreasing function of the pressure may, if the temperature, the initial pressure, and the final pressure are appropriately chosen, be equivalent to a rapid thermal quenching. In particular, it may lead to the formation of metas…
We investigate the morphology of porous layers obtained by electrochemical anodization of (100)-oriented n-type GaP substrates before and after a preliminary 5-MeV Kr+ implantation. Apart from favoring the observation of a surface-related phonon in the frequency gap between the bulk optical phonons, ion implantation a…
We have observed a sharp and nonmonotonic crossover of the susceptibility (osmotic compressibility) from mean-field to Ising critical behavior in semidilute solutions of polystyrene in deuterocyclohexane as the temperature decreases from the $\ensuremath{\Theta}$ region down to the critical temperature of the phase se…
The Mn site substitutions of charge ordered (CO) manganites Ln0.5Ca0.5MnO3 (Ln=La–Tb) have been investigated. Among the different studied doping elements, chromium is shown to be the most efficient one to induce a metal insulator (MI) transition in the CO undoped insulators. A new Tm(〈rA〉) magnetic diagram, where 〈rA〉…
We have developed a process for making thick, stress-free, amorphous-tetrahedrally bonded carbon (a-tC) films with hardness and stiffness near that of diamond. Using pulsed-laser deposition, thin a-tC films (0.1–0.2 μm) were deposited at room temperature. The intrinsic stress in these films (6–8 GPa) was relieved by a…
Molecular dynamics simulations were performed to study the phase behavior of a thin film of water confined to a slit nanopore with smooth walls. A first-order water-to-ice freezing transition has been observed. The resulting ice, which is a crystal of bilayer consisting of rows of distorted hexagons, does not resemble…
We determined experimentally two critical points in elastic electron scattering by argon where the differential cross section (DCS) attains its smallest values. The points were found to be at and at . Special attention was given to improve the angular resolution in order to determine the exact positions of the minima.…
A novel graft copolymer of unsaturated propylene with methyl methacrylate (uPP-g-PMMA) was added to binary blends of isotactic polypropylene (iPP) and atactic poly(methyl methacrylate) (aPMMA) with a view to using such a copolymer as a compatibilizer for iPP/aPMMA materials. Optical microscopy (OM), scanning electron…
A new silicon-containing maleimide monomer, N-(tert-butyldimethylsilyloxy)-maleimide (SiOMI) has been synthesized. SiOMI was radically copolymerized with styrene derivatives (XSt) to obtain alternating copolymers, P(SiOMI/XSt), in high conversions. The copolymers have high glass transition temperatures above 190°C, an…
The effect of toluene diisocyanate (TDI) index on the physical properties, structure, and morphology of flexible slabstock polyurethane foams was investigated. Foams based on a 2700 molecular weight triol, 6 pph water, and varying amounts of an 80/20 mixture of 2,4- and 2,6-TDIs were characterized using a number of ph…
In this work, the melt crystallization of immiscible blends of isotactic polypropylene (iPP) and branched polyethylenes (PE) was followed by oscillatory shear measurements during controlled cooling. All the blends contained 20% iPP finely dispersed in several ethylene/α-olefin copolymer matrices (with and without a nu…
Stokesian Dynamics has been used to investigate the origins of shear thickening in concentrated colloidal suspensions. For this study, we considered a monolayer suspension composed of charge-stabilized non-Brownian monosized rigid spheres dispersed at an areal fraction of ϕ a =0.74 in a Newtonian liquid. The suspensio…
We present first-principles band calculations as well as structural optimization of the orthorhombic K$_1$C$_{60}$ polymerized phase. We found three-dimensional inter-fullerene bonding/anti-bonding characters consisting of $t_{1u}$ molecular orbitals with $p$-like symmetry in the conduction bands. The formation of the…
Spin polarized B12 nuclei were produced in a B11(d,p)12B nuclear reaction and recoil implanted into a type Ib diamond sample at doses below 1011 cm−2. β-radiation detected nuclear magnetic resonance spectra were measured directly after implantation at sample temperatures ranging from 300 to 800 K. The polarization asy…
We formulate and apply the EOM-CC method to determine, recursively, any order and any process frequency dependent hyperpolarizability. Combining the theory with systematically chosen n-aug-cc-pVXZ bases, we attempt to converge to the basis set limit. Our best “relaxed” result is −9.8±0.5 a.u. for βSHG compared to an e…
Domain–wall contribution to the longitudinal piezoelectric coefficient d33 is calculated theoretically for prepolarized tetragonal ferroelectric thin films epitaxially grown on cubic substrates. To that end, translational vibrations of ferroelastic 90° domain walls induced by a weak measuring electric field are analyz…
We propose a hierarchical classification of kink species in dislocation cores which considers three sources of broken symmetry, host lattice structure, character of the dislocation, and core reconstruction effects. Kink multiplicity in bcc and diamond cubic lattices is examined and verified directly by atomistic calcu…
Computer simulations of the short-time, vibrational dynamics of the network-forming ionic melts, LaCl3 and ZnCl2, and of their mixtures with network-breaking alkali halides are described. In the mixtures, high frequency peaks in the vibrational density of states are shown to be describable in terms of the normal coord…
Efficient recording of polarization gratings in dye-doped liquid crystals is reported. By exploiting the effect of light-induced anchoring of the molecular director, it has been possible to write stable holographic gratings with a diffraction efficiency of 8% at a resolution of 1000 lines/mm. The required surface ener…