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。
Infrared reflectivity spectra were measured for a polycrystalline ${\mathrm{La}}_{0.7}$${\mathrm{Ca}}_{0.3}$Mn${\mathrm{O}}_{3}$ sample. The internal phonon modes, i.e., the bending and stretching modes, of the Mn${\mathrm{O}}_{6}$ octahedra show significant frequency shifts near the Curie temperature ${T}_{C}$. The f…
The (001) surfaces of cubic SiC were investigated with ab-initio molecular dynamics simulations. We show that C-terminated surfaces can have different c(2x2) and p(2x1) reconstructions, depending on preparation conditions and thermal treatment, and we suggest experimental probes to identify the various reconstructed g…
The switching of the magnetization of single Ni wires with diameters 40-100 nm was measured at temperatures between 0.13 and 6 K. The angular dependence of the switching field was studied for several wire diameters. Repetitive measurements allow us to obtain histograms of the switching field values. For the smallest d…
A three-dimensional computer simulation of a concentrated emulsion in shear flow has been developed for low-Reynolds-number finite-capillary-number conditions. Numerical results have been obtained using an efficient boundary integral formulation with periodic boundary conditions and up to twelve drops in each periodic…
Local Spin Density Approximation (LSDA) is used to calculate the energy bands of both the ferromagnetic and paramagnetic phases of metallic CrO_2. The Fermi level lies in a peak in the paramagnetic density of states, and the ferromagnetic phase is more stable. As first predicted by Schwarz, the magnetic moment is 2 μ_…
Silk fibers were treated with methacrylamide (MAA), and changes in the mechanical properties of the silk fibers were investigated. The breaking load of the silk fibers was almost unchanged, whereas rigidity was markedly increased by the methylmethacrylate (MAA) treatment. Elongation at break of the silk fibers decreas…
Abstract Unlike their predecessors based on Sm-Co, the Nd-Fe-B alloys can be processed into permanent magnets by many different routes. The most important group of processing routes consists of variants of powder metallurgy, where monocrystalline powder with grains a few microns in size is oriented and sintered to yie…
It is common practice to accept, as an operational definition, that particulate matter (PM) refers to particles greater than 0.45 µm. By this definition dissolved matter includes particles finer than 0.45 µm, including colloids. Particulate matter is derived primarily from rock weathering processes, both physical and…
The recycled poly(ethylene terephthalate) (R-PET) from the recovery of a blow-molded bottle is studied with its crystalline behavior in terms of glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and its dynamic crystallization kinetics. These crystalline behaviors offer an…
The dipolar-correlation effect on the stimulated echo of nematics probes (a) the order parameter and (b) the distribution of the director fluctuations. This effect was employed for the study of orientational director fluctuations in a nematic liquid crystal confined in Bioran porous glasses with mean pore diameters of…
The structure and formation mechanism of carbon gel in carbon black filled polyisoprene composites were studied by the pulsed NMR technique. The composites were prepared from a wide range of molecular weights by a solution blend. The carbon gels were extracted from the composites by a solvent-extraction method. The co…
Elastomers cured with two crosslinking systems such as sulfur and the polymerization products of p-benzoquinone are shown to have much improved overall mechanical properties. It was thought that this was because of the antioxidizing potency of the quinone polymers that act as radical traps during the oxidative degrada…
The two reactive systems using cellulosic fiber reinforcement emphasized in this article are twin screw extrusion maleation of polypropylene (PP) and structural reaction injection molding (SRIM). Both simultaneous and sequential compounding of sweet gum wood fiber (WF) with maleation were studied. Similar PP/WF mechan…
Given a ‘‘target’’ sphere of radius r1 and ‘‘probe’’ spheres of radius r2, we consider, as a function of r2/r1, how many probe spheres, on average, can be attached to the target sphere if (1) the attachment sites are chosen at random, (2) the probe spheres are not permitted to overlap, and (3) each attachment is irrev…
Acrylic acid was grafted onto the surface of commercial poly(vinylidene fluoride) (PVDF) membrane using plasma polymerization techniques. Graft reaction was confirmed by X-ray photoelectron spectroscopy (XPS) spectra and attenuated total reflectance Fourier transform infrared spectra. Grafting rate was dependent on pl…
To explore the possibility of producing branched polypropylene (PP) by a reactive extrusion (REX) process, isotactic PP was reacted with a polyfunctional monomer, pentaerythritol triacrylate (PETA), in the presence of 2,5-dimethyl-2,5(t-butylperoxy) hexane peroxide (Lupersol 101). Experiments were carried out in an in…
Concentrated γ-crystallin and lysozyme solutions have been reported to undergo a fluid–fluid phase separation when cooled below a critical temperature. This behavior is under control of the weak forces acting in solution between macromolecules. We have used small angle x-ray scattering at the synchrotron radiation fac…
A nonequilibrium molecular dynamics algorithm is employed to study a fluid confined between two immobile walls. The linear response theory of Bocquet and Barrat [Phys. Rev. E 49, 3079 (1994)] is used to relate phenomenological parameters, which determine the boundary conditions of the interface, to averages over micro…
We present a method for calculating ab initio interatomic forces which scales quadratically with the size of the system and provides a physically transparent representation of the force in terms of the spatial variation of the electronic charge density. The method is based on a reciprocity theorem for evaluating an ef…
Abstract Rare-earth iron permanent magnets combine the magnetization of iron or cobalt with the anisotropy of a light rare-earth in intermetallic compounds which exhibit nearly ideal hysteresis. The rare-earth iron magnets are now indispensable components of a vast range of electronic and electromechanical devices. Th…