Materials Literature
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Materials exhibiting gas permeable porosity are of particular interest for a number of functional applications. Here, the authors show a new nanoporous superalloy membrane, far surpassing existing gas permeable porous metals in fineness and regularity of the porosity. This may not only open the path for new medical ap…
Simulations of nanocrystalline materials reveal that the pressure gradient present within the structure can play a key role in the movement of self-interstitial atoms (SIA's) to surrounding grain boundaries and therefore in the resulting defect structure formed during displacement cascades. Initially SIA's sense the g…
Here, we introduce the synthesis, characterization, and surface orientation properties of a new generation of biodegradable and biomimetic polymers. These phospholipid-mimetic, biodegradable polymers are synthesized by combining poly ε-caprolactone (PCL) with various functional polar end-groups, including zwitterionic…
Multiple-walled carbon nanotubes (MWNTs) were chemically modified by a ligand-exchange reaction of ferrocene (Cp-Fe-Cp). The modified MWNTs (Cp-Fe-MWNTs) were next monolithiated by tert -butyllithium and terminated by p -chloromethylstyrene ( p MS). The p MS - terminated species ( p MS-Cp-Fe-MWNTs) were then functiona…
Scanning tunneling microscopy studies of vanadium oxides grown on Pd(111) show interesting structures especially in the low-coverage region. Evaporation of V in an oxygen background at elevated sample temperature $(250\ifmmode^\circ\else\textdegree\fi{}\mathrm{C})$ results in the formation of a nonperiodic honeycomb-l…
Surface structures of asymmetric poly[styrene- block -4-(perfluorooctylpropyloxy)styrene] block copolymers (PS−PF) with the shorter PF block than the PS block have been investigated using X-ray photoelectron spectroscopy (XPS) and dynamic secondary ion mass spectrometry (SIMS). Fluorooctyl side groups (C 8 F 17 ) of t…
Two aspects of the deformation behavior of magnesium sheets are the subject of this paper. First it will give a mechanical characterization of a commercial magnesium with a focus on the anisotropy and the possible microstructural causes of this behavior. The rolling process will be part of the second aspect. The aim i…
Abstract Development of magnesium die casting alloys is the art of combining a thorough understanding of thermodynamic aspects of alloy composition and phase formation with the solidification kinetics as experienced in the die casting process. The microstructures obtained will determine The Alloy Property profile, whi…
Simulations of the optical absorption in bismuth nanowires resulting from an indirect interband $L\ensuremath{-}T$-point transition are presented. The absorption dependence at room temperature on the band overlap, effective masses, and wire diameter is explored. The polarization, wave number, and wire size dependence…
Thin films of the perchlorate salt of an [Os(N,N'-alkylated-2,2'-biimidazole3)2+/3+-containing polymer have been formed on planar platinum microelectrodes. The electrochemical response associated with the Os2+/3+ couple occurs at -0.19 V. In aqueous perchlorate media at near-neutral pH the voltammetric response is clo…
The dynamic density functional (DDF) theory and standard Brownian dynamics simulations (BDS) are used to study the drifting effects of a colloidal particle in a polymer solution, both for ideal and interacting polymers. The structure of the stationary density distributions and the total induced current are analyzed fo…
Amphiphilic, diblock copolypeptides of hydrophilic lysine or glutamic acid and hydrophobic leucine or valine have been observed to self-assemble into rigid hydrogels in aqueous solution at neutral pH and very low volume fraction of polymer, > or =0.5 wt % polypeptide. Laser scanning confocal microscopy and ultra small…
A model for the structure of amorphous molybdenum trisulfide, a-MoS3, has been created using reverse Monte Carlo methods. This model, which consists of chains of MoS6 units sharing three sulfurs with each of its two neighbors and forming alternate long, nonbonded, and short, bonded, Mo-Mo separations, is a good fit to…
The spreading of polymer droplets is studied using molecular dynamics simulations. To study the dynamics of both the precursor foot and the bulk droplet, large hemispherical drops of 200 000 monomers are simulated using a bead-spring model for polymers of chain length 10, 20, and 40 monomers per chain. We compare spre…
By using the in situ thermal analysis-mass spectroscopic technique, combined with transmission electron microscopic characterization of the carbon nanotube (CNT) product, we have studied the chemical vapor deposition (CVD) growth of CNTs with Fe-Co/gamma-Al2O3 catalyst and benzene precursor in the range of room temper…
We report high q-resolution neutron scattering data on $\mathrm{PMN}\ensuremath{-}x\mathrm{PT}$ single crystals with $x=20%$ and $27%.$ No rhombohedral distortion occurs in the 20PT sample for temperatures as low as 50 K. On the other hand, the 27PT sample transforms into a rhombohedral phase below ${T}_{C}\ensuremath…
PEGylated gold nanoparticles with biotin moieties installed at the distal end of the PEG tethered chains were prepared by the autoreduction of HAuCl4 catalyzed by alpha-biotinyl-PEG-block-poly[2-(N,N-dimethylamino)ethyl methacrylate] (biotinyl-PEG/PAMA) in aqueous medium at room temperature. The size of the gold nanop…
Nanoscale uniform films containing gold nanoparticle and polyelectrolyte multilayer structures were fabricated by the using spin-assembly or spin-assisted layer-by-layer (SA-LbL) deposition technique. These SA-LbL films with a general formula [Au/(PAH-PSS)nPAH]m possessed a well-organized microstructure with uniform s…
We predict the stability and electronic structure of aluminum nitride nanotubes based on calculations using density functional theory. The lower strain energy required in order to wrap up an AlN graphitic sheet into a tube and good thermal stability indicate the possibility for the formation of AlN nanotubes. All the…
We use density-functional theoretical methods to examine the recent prediction, based on a mean-field solution of the Zener model, that diamond doped by Mn (with spin $S=5/2)$ would be a dilute magnetic semiconductor that remains ferromagnetic well above room temperature. Our findings suggest this to be unlikely, for…