Materials Literature
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Poly(ethylene glycol) (PEG)-modified poly(lactic acid) (PLA) systems were created by physically entrapping the modifying species at the PLA surface. The surface characterization and biological performance of these materials are described. This modification strategy is performed by reversible gelation of the PLA surfac…
Abstract The flammability performance and mechanical behaviors for halogen‐based and non‐halogen‐based flame retardant (FR) filled polypropylene (PP) composites were investigated in this study. The halogen‐based FR system consisted of a mixture of brominated phosphate ester and antimony trioxide (BR), and the halogen‐…
Substrate effects, volume reproducibility, and pH effects on the size and shape of ethylenediamine core poly(amidoamine) dendrimers (generations 6−9) were explored using tapping mode atomic force microscopy (AFM) measurements. A statistical analysis of the measurements indicated a 4% variation in volume for repeated m…
From the reactions between 2,2‘-ethylidenebis(4,6-di- tert -butylphenol) and 2,2‘-methylidenebis(4-dimethyl-6-di- tert -butylphenol) and Et 2 AlCl the biphenoxide complexes [(O∼∼CHMe∼∼O)AlCl] 2, 1, and [(O∼∼CH 2 ∼∼O)AlCl] 2, 2, have been isolated and characterized. These dimers are broken up by donor ligands, and the…
The synthesis of four lipids containing the hemithioindigo chromophore as part of the fatty acid is described. Heck reaction of bromophenyl thioacetate esters with acrylonitrile, followed by reduction, ester hydrolysis, and Friedel--Craft acylation--cyclization gave a substituted thioindoxyl that condensed with an alk…
We report the results of a calculation of the vibrational and rotational spectra of water confined in carbon nanotubes. Water has been modeled with a flexible version of the simple point charge model of Berendsen et al., while the carbon nanotubes are taken to be soft potential walls interacting with water through a L…
Sodium manganese oxide octahedral molecular sieves with a 2 × 4 tunnel structure (Na−2 × 4) have been hydrothermally synthesized from Na−birnessite materials at low temperatures and pressures. The synthetic template materials, the pH value of the medium, and the autoclaved temperature are critical in the synthesis. So…
A new approach is proposed for the synthesis of extra-large-pore (diameter > 7 nm) MCM-41 analogues, potentially useful as hosts for the synthesis of nanowires and as model porous solids for fundamental research. The approach is based on the recently demonstrated opportunity for elimination of the connecting pores in…
2-Amino-3-ketobutyrate CoA ligase (KBL, EC 2.3.1.29) is a pyridoxal phosphate (PLP) dependent enzyme, which catalyzes the second reaction step on the main metabolic degradation pathway for threonine. It acts in concert with threonine dehydrogenase and converts 2-amino-3-ketobutyrate, the product of threonine dehydroge…
The growth and structuring of polyelectrolyte self-assemblies (so-called “multilayers”) made from a lyotropic ionene and a strong polyelectrolyte are examined in depth using X-ray reflectometry among other techniques. We show that highly ordered polyelectrolyte films may be obtained, consisting of a regular lamellar n…
In this paper the glass transition temperature ( T g ) in thin polymer films has been studied. Ellipsometry has been used to measure T g of poly(α-methylstyrene) (PAMS) thin films as a function of the film thickness for two molecular weights. When the films were thinner than a few hundred angstroms, substantial reduct…
In many oxides of the perovskite and pseudoperovskite families there are phase transitions between insulating and normal metallic (Fermi liquid) phases that are separated by an intermediate phase that is often called a non-Fermi liquid (NFL). The dc resistivity of the intermediate or NFL phase often exhibits a T tempe…
High real-space resolution atomic pair distribution functions (PDF's) have been obtained from ${\mathrm{ZnSe}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$ using neutron powder diffraction. Distinct Zn-Se and Zn-Te nearest-neighbor (nn) bonds, differing in length by $\ensuremath{\Delta}r=0.14$ \AA{}, are resolved in the measu…
In order to tailor the properties of nanodots, it is essential to separate the effects of quantum confinement from those due to the surface, and to determine the mechanisms by which preparation conditions can influence the properties of the dot. We address these issues for the case of small Ge clusters (1--2.5 nm), us…
Superconducting transition temperatures ($T_c$'s) of MgB$_2$, Mg$_{1-x}$Ca$_x$B$_2$, Mg$_{1-x}$Na$_x$B$_2$, and Mg$_{1-x}$Al$_x$B$_2$ are studied within the McMillan approximation using electronic and structural information obtained from density functional theory within the generalized gradient approximation. The dens…
Fascinating properties of nanotubes arise when they form intermolecular junctions. In this rapid communication, we demonstrate that such nanotube junctions have atomic scale characteristics and the contact resistance between the tubes depends strongly on atomic structure in the contact region. Our calculations show th…
We report high-pressure Raman measurements (up to 19 GPa) on the perovskite-type relaxor ferroelectric sodium-bismuth-titanate, ${\mathrm{Na}}_{0.5}{\mathrm{Bi}}_{0.5}{\mathrm{TiO}}_{3}$ (NBT). Distinct changes in the Raman spectra have been analyzed in the light of a rhombohedral-to-orthorhombic $(R3c\ensuremath{-}\m…
We are reporting here on the inexpensive fabrication of large three-dimensional and highly oriented porous microrod array of n-type ZnO semiconductor with a unique designed architecture consisting of well-defined, length-tailored, monodisperse, perpendicularly oriented single-crystalline hexagonal rods, grown directly…
Zinc II hexacyanoferrate III, Zn 1.5 [Fe(CN) 6 ]·6H 2 O, was prepared by coprecipitation method. The precipitated powder possessed a face-centred cubic structure with a lattice parameter of 10.32 Å. Phase transformation in this cyanide compound was encountered after heat treatment at a temperature at 75 °C or above, f…
Abstract Three series of new thermoplastic, high molecular weight, segmented thiopolyurethanes were synthesized by a one‐step melt polymerization from newly obtained thiodiols, including bis[4‐(2‐hydroxyethyl)thiomethylphenyl]methane, bis[4‐(3‐hydroxypropyl)thiomethylphenyl]methane, and bis[4‐(6‐hydroxyhexyl)thiomethy…