Materials Literature
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Wormhole HMS silica molecular sieves with average framework pore sizes in the range 2.9 to 4.1 nm were assembled from 4:1 molar mixtures of TEOS as the inorganic precursor (I o ) and dodecylamine as the structure-directing surfactant (S°) in 63:27 (v/v) water/ethanol. Increasing the assembly temperature from 25 °C to…
A series of double-comb, disubstituted polysiloxane polymers have been prepared containing oligoethylene oxide units, CH 3 (OCH 2 CH 2 ) n (CH 2 ) 3 −, in the side chains. These polymers were doped with LiN(SO 2 CF 3 ) 2 (LiTFSI, 1 ), and conductivities of the polymer-salt complexes were determined as a function of te…
The foaming of thin (∼100 μm) polysulfone (PSU), poly(ether sulfone) (PES), and cyclic olefin copolymer (COC) films using carbon dioxide as a physical blowing agent has been studied. Microcellular foam morphologies were obtained by saturating the polymer with carbon dioxide and heating the sample above the glass trans…
A theory for the ab initio calculation of all-electron NMR chemical shifts in insulators using pseudopotentials is presented. It is formulated for both finite and infinitely periodic systems and is based on an extension to the Projector Augmented Wave approach of Bloechl [P. E. Bloechl, Phys. Rev. B 50, 17953 (1994)]…
We present the theoretical design of quantum dot (QD) artificial ferromagnetic crystals. The electronic structure calculations based on local spin density approximation (LSDA) show that our designed QD artificial crystal from a structure comprising the crossing 0.104-micrometer-wide InAs quantum wires (an effective Ka…
Within a phenomenological approach the density of induced uniaxial anisotropy in nanostructures K(r) is treated as a physical field additional to the magnetization M(r). The equilibrium distributions of K(r) are formed under the influence of the surfaces and internal interactions. The functions K(r) and M(r) are calcu…
The fabrication, initial structural characterization and diode measurements are reported for the first boron carbide / silicon carbide heterojunction diode. Current-voltage curves obtained for operation at temperatures from 24 C to 388 C. PECVD-deposited undoped boron carbide material is highly crystalline and consist…
We study linear electron transport through a molecular wire sandwiched between nanotube leads. We show that the presence of such electrodes strongly influences the calculated conductance. We find that depending on the quality and geometry of the contacts between the molecule and the tubular reservoirs, linear transpor…
The structure of the multilayer assemblies of yttrium iron garnet nanoparticles (YIG) with polyelectrolytes was investigated with the emphasis on the control of the particle density in the adsorption layers. It was found that the growth of YIG films prepared by the layer-by-layer assembly can occur via two deposition…
A novel strategy to synthesize amphiphilic surface-compartmentalized nanoparticles based on linear ABC triblock copolymers is presented. These so-called Janus micelles consist of a cross-linked core and a corona with a “northern” and a “southern” hemisphere. Selectively cross-linking spherical domains of the polybutad…
The present work reports the synthesis and the characterization of cobalt oxide thin films obtained by chemical vapor deposition (CVD) on indium tin oxide (ITO) substrates, using a cobalt(II) β-diketonate as precursor. The complex is characterized by electron impact mass spectrometry (EI-MS) and thermal analysis in or…
Various diols were polycondensed with dicarboxylic dichlorides in the presence of pyridine or γ-picoline. Aliphatic dicarboxylic acid dichlorides were reacted with 1,4-butanediol, catechol resorcinol, methylhydroquinone or bisphenol A. Isophthaloyl chloride was polycondensed with α,ω-dihydroxyalkanes, methylresorcinol…
Among the most common diatoms in arctic spring blooms are Fossula arctica Hasle, Syvertsen et von Quillfeldt, Fragilariopsis cylindrus (Grunow) Krieger in Helmcke et Krieger, F. oceanica (Cleve) Hasle, Thalassiosira antarctica var. borealis Fryxell, Doucette et Hubbard, T. hyalina (Grunow) Gran and Chaetoceros sociali…
In this paper we review the fracture mechanics of smooth cracks in micropolar (Cosserat) elastic solids. Griffith’s fracture theory is generalized for cracks in micropolar solids and shown to have two possible forms. The effect of fractality of fracture surfaces on the powers of stress and couple-stress singularity is…
A novel macromer, oligo(poly(ethylene glycol) fumarate) (OPF), was synthesized by the reaction between poly(ethylene glycol) (PEG) of molecular weight 1000 (PEG 1.0K) and fumaryl chloride. The oligo(PEG fumarate) (OPF 1.0K) was modified with a peptide known to modulate cellular functions, Gly-Arg-Gly-Asp (GRGD), after…
[figure: see text] Low-valent rhodium complexes are efficient catalysts for the activation of alpha-C-H bond of isonitriles. Addition of isonitriles to carbonyl compounds proceeds under mild and neutral conditions to give the corresponding alpha,beta-unsaturated formamides. Catalytic synthesis of pyrroles can be perfo…
We report here the design, synthesis, and characterization of new (dioxo)Mo(VI) epoxidation catalysts based on monoanionic tridentate ligands. Two important features distinguish these catalysts from those previously reported. First, their coordination environment remains well-defined during the epoxidation reaction. S…
Colloidal silver nanoparticles were synthesized in supercritical ethane at 80 °C and 80−120 bar, with methanol as cosolvent. Solvated electrons, produced by a pulse of 20 MeV electrons, reduced the silver ions. The time-resolved technique of pulse radiolysis was employed to characterize the reduction products and coll…
We prove that for a wide class of quantum spin systems with isotropic Heisenberg coupling the energy eigenvalues which belong to a total spin quantum number S have upper and lower bounds depending at most quadratically on S. The only assumption adopted is that the mean coupling strength of any spin w.r.t. its neighbou…
Microstructural characterization of synthetic periodic multilayers by x-ray standing waves have been presented. It has been shown that the analysis of multilayers by combined x-ray reflectometry (XRR) and x-ray standing wave (XSW) techniques can overcome the deficiencies of the individual techniques in microstructural…