Materials Literature
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The preparation of poly( N -isopropylacrylamide)-monolayer-protected clusters (PNIPAM-MPC) of gold nanoparticles was carried out in a homogeneous phase using three methods, in which three types of PNIPAM ligands were employed. The first type was comprised of PNIPAMs with narrow molar mass distributions, synthesized by…
Single walled carbon nanotubes (SWNTs) have been coated with silica by the addition of a silica/H 2 SiF 6 solution to a surfactant-stabilized solution of SWNTs. The thickness of the coating is controlled by reaction time, while the coating of individual SWNTs versus small ropes is controlled by the choice of surfactan…
I analyze the Nonlocal Conserved Kardar-Parisi-Zhang (NCKPZ) equation with spatially correlated noise. This equation is also known as the Nonlocal Molecular Beam Epitaxy (NMBE) equation andv was originally suggested to study the effect of the long-range nature of interactions coupled with spatially correlated noise on…
We study the effect of spatial dispersion of crystal modes on optical properties such as the reflectivity $R$. As an example for isotropic media, we investigate the simplest model for phonons in ionic crystals and compare with previous results for highly anisotropic plasmons, which are now understood from a more gener…
We have used a tight-binding model that is fit to first-principles electronic-structure calculations for titanium to calculate quasi-harmonic phonons and the Gibbs free energy of the hexagonal close-packed (hcp) and omega crystal structures. We show that the true zero-temperature ground-state is the omega structure, a…
The complex band structure of an isolated polyethylene chain is calculated within Density Functional Theory (DFT). A plane wave basis and ultrasoft pseudopotentials are used. The results are compared with those obtained via a local basis set. We obtain a gap between the highest occupied molecular orbilar (HOMO) and th…
We report on the first Raman data of Cu substituted La(1-y)Sr(y)Mn(1-x)Cu(x)O3 (0 < x < 0.10 and 0.17 < y < 0.3, accordingly in order to have the same Mn(4+)/[Mn(4+)+Mn(3+)] ratio), collected in the frequency range 100-900 cm-1 and at room temperature, with parallel and crossed polarizations of the incident and scatte…
The T-dependence of magnetic moments in SrB_6 is studied through spin-polarized band calculations for a supercell of Sr_{27}B_{156} containing a B_6 vacancy. The magnetic moment decays rather quickly with T despite the fact that only electronic Fermi-Dirac effects are included. This result and the T-dependence of mome…
No metal jacket required: The surface structures of mesoporous materials were accurately determined by using electron-microscopy techniques—without the need for metal plating. The effectiveness of these techniques was demonstrated with SBA-15 mesoporous silica (see image) and its CMK-5 carbon replica, for which high-r…
Very different electronic properties are found in the hexagonal and lamellar nanocomposite films (see schematic representations) prepared by dilution of a pyrrole-containing surfactant with nonpolymerizable surfactants in a sol–gel-based template polymerization. The hexagonal composite film comprises a thin polypyrrol…
In an effort to make semiconductor nanomaterials with tunable properties, we have deliberately designed and synthesized a family of novel organic-inorganic hybrid nanocomposites based on II-VI semiconductors with structures ranging from one-dimensional (1-D) chain to two-dimensional layer (2-D) to three-dimensional (3…
A recent paper [J. B. Pendry, Phys. Rev. Lett. 85, 3966 (2000)] showed how to construct a superlens that focuses the near-field radiation and, hence, produce an image resolution unlimited by wavelength. The prescription requires lossless materials with a negative refractive index: finite loss cuts off the finer detail…
By means of ab initio supercell calculations based on the density-functional theory, we have investigated stability of hydrogen-monovacancy complexes $({\mathrm{VH}}_{n})$ and their binding preferences in $\ensuremath{\alpha}\ensuremath{-}\mathrm{Fe}.$ We have found that ${\mathrm{VH}}_{2}$ is the major complex at amb…
We present the results of a comprehensive investigation of the dc magnetization, ac susceptibility, and magnetotransport properties of the glassy ferromagnet ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3}.$ The compositions studied span the range from the end-member ${\mathrm{LaCoO}}_{3}$ $(x=0.0…
The apparent contact angle on a rough surface is usually modeled by either Cassie's or Wenzel's theory. We show, on the basis of experimental evidence, that there can be two contact angles on the same rough surface, depending on how a drop is formed. A transition can occur between the different states by an external d…
OBJECTIVES: To develop and test a new concept of the degradation kinetics of newly developed coronary stents consisting of magnesium alloys. METHODS: Design of a coronary stent prototype consisting of the non-commercial magnesium based alloy AE21 (containing 2% aluminium and 1% rare earths) with an expected 50% loss o…
Insertion of spherical particles into a uniform nematic liquid crystal gives rise to the formation of topological defects. In the present work, we investigate how a spherical particle accompanied by its topological defects interacts with neighboring disclination lines. We perform two- and three-dimensional dynamic sim…
The structure of Ge nanocrystals embedded into a ${\mathrm{SiO}}_{2}$ matrix on either Si(100) or quartz-glass substrates has been studied by transmission electron microscopy, x-ray absorption fine structure, and Raman scattering. The size of the nanocrystals (5--20 nm) is found to strongly depend on the substrate mat…
Abstract A novel triblock polyisocyanide having free-base- and zinc-porphyrins as pendants was prepared by living polymerization with a Pt-Pd μ-ethynediyl complex as an initiator, and irradiated at 420 or 556 nm in a THF solution to cause intramolecular energy transfer from the zinc-porphyrin to the free-base-porphyri…
A tri-block coupling-polymer composed of 4,4'-methylenediphenyl diisocyanate and poly (ethylene oxide) (PEO), abbreviated MPEO, was used as the template surface-modifying additive (SMA), based on which selected amino acids (lysine, arginine, glycin, and aspartic acid) and RGD peptide were respectively conjugated as fu…