Materials Literature
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Well-defined amphiphilic telechelics incorporating polyhedral oligosilsesquioxane (POSS) were synthesized by direct urethane linkage between the diol end groups of poly(ethylene glycol) (PEG) homopolymers and the monoisocyanate group of POSS macromers. The hydrophobicity of the amphiphilic telechelics was varied by us…
First-principles pseudopotential density-functional calculations for pentacene and anthracene are used to obtain atomic structures, cohesive energies, and surface energies for the low index surfaces. For pentacene, calculations predict that the (001) surface has a much lower surface energy than the other surfaces. Fro…
Although polyamide “nylon 6” polymer is an important industrial material, there remain many questions about the details of the various structures and the conversion between them. Using the MSXX force field (developed previously from ab initio quantum calculations), we predict the crystal structures, folds, and lamella…
The structure of the pseudo-binary mercury chalcogenide alloy HgSe0.7S0.3 has been studied by means of X-ray and neutron powder diffraction at pressures up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P ~ 1 GPa. A phenomenological model of this…
Insertion of a resistive contact between a ferromagnetic metal and a semiconductor microstructure is of critical importance for achieving efficient spin injection into a semiconductor. However, the equations of the diffusion theory are rather cumbersome for the junctions including such contacts. A technique based on d…
Local-density-functional method is used to study the electronic properties of single-wall carbon nanotubes with very small diameters of about $4\mathrm{\AA{}},$ which have recently been synthesized inside zeolite channels. Our calculated results indicate that both the (5,0) and (3,3) tubes are metallic, while the (4,2…
We investigate the effects of strain on a crystal surface close to the bulk melting temperature T_m, where surface melting usually sets in. Strain lowers the bulk melting point, so that at a fixed temperature below but close to T_m the thickness of the quasi-liquid film is expected to grow with strain, irrespective of…
Computer simulations of bubble oscillations are performed under conditions of multibubble sonoluminescence (MBSL) in water for various ultrasonic frequencies. The range of the ambient bubble radius for sonoluminescing bubbles narrows as the ultrasonic frequency increases; at 20 kHz it is 0.1-100 microm while at 1 MHz…
The Heusler alloy ${\mathrm{Co}}_{2}\mathrm{MnSi}$ is predicted to be a half-metallic ferromagnet and thus is considered a promising candidate for incorporation into spintronic devices. Recent theoretical calculations have shown that antisite disorder of a few percent in some Heuslers can destroy half metallicity, emp…
There is great interest in using single-walled carbon nanotubes (SWNTs) as nanoscale probes and sensors in biological electronics and optical devices because the electronic and optical properties of SWNTs are extremely sensitive to the surrounding environments. A well-controlled modification of SWNT surfaces may provi…
A pH above 9.0 was essential for the formation of wurtzite zinc oxide (ZnO) in aqueous solution systems. The addition of complexing agents to decrease the deposition rate was required for the direct growth of ZnO on the surface of substrates through heterogeneous nucleation. The nucleation of the crystals was promoted…
Electrospun fibers were produced using a variety of solvents to investigate the influence of polymer/solvent properties on the fiber surface morphology. Electrospinning is a novel processing technique for the production of fibers with diameters in the range of a few nanometers to tens of micrometers. We have been able…
PbSeTe-based quantum dot superlattice structures grown by molecular beam epitaxy have been investigated for applications in thermoelectrics. We demonstrate improved cooling values relative to the conventional bulk (Bi,Sb)2(Se,Te)3 thermoelectric materials using a n-type film in a one-leg thermoelectric device test set…
We report a technique devised to evaluate the effects of partial proteolysis on the mechanical characteristics of acellular non-cross-linked fibrin clots. The destruction technique applies coaxial tension on mechanically preconditioned cylindrical molded clots and measures the number of mechanical failures vs the tota…
Diffusion has a central role in protein crystal growth both in microgravity conditions and on ground. Recently several reports have been focused on the importance to use the generalized Fick's equations in n-component systems where crystals grow. In these equations the total flux of each component is produced by the o…
Two crystallographic forms of lysozyme nitrate are known, namely monoclinic and triclinic. Having previously determined the temperature dependence of the solubility of the monoclinic form (0.2 M NaNO (3) solutions at pH = 4.5) [Legrand et al. (2001). J. Crystal Growth 232, 244-249], we focus here on the solubility of…
In a classical vapor diffusion crystallization, the protein solution is mixed in a 1:1 ratio with the reservoir solution, containing one or more precipitant species, after which the two are placed in an enclosed chamber. As the vapor pressure is lower for the reservoir solution, due to its higher solute concentration,…
We calculate the lattice phonons and the electron-phonon coupling of the organic superconductor $\ensuremath{\kappa}\ensuremath{-}(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{T}\mathrm{F}{)}_{2}{\mathrm{I}}_{3},$ reproducing all available experimental data connected to phonon dynamics. Low-…
The vanadium dioxide (VO2) thin film, usually employed as an infrared detector, exhibits hysteresis in its resistance-temperature characteristic. Considering a polycrystalline VO2 thin film as a composite medium, containing semiconducting and metallic microcrystals, the well- known effective-medium approximation theor…
The influence of an external field acting differently on the two constituents of a binary colloidal mixture performing Brownian dynamics is investigated by computer simulations and a simple theory. In our model, half of the particles (A particles) are pulled by an external force ( A ) while the other half (B particles…