Materials Literature
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With a Si(001) vicinal surface in mind, we study step wandering instability on a vicinal surface with an anisotropic surface diffusion whose orientation dependence alternates on each consecutive terrace. In a conserved system step wandering takes place with step-up adatom drift. Repulsive interaction between steps is…
New immobilization of the chiral Mn(salen) complex through the complexation of managanese by oxygen atoms of the phenoxyl groups grafted on the surface of MCM-41 leads to a markedly higher ee than for the free complex.
We study a classical double exchange magnet with direct antiferromagnetic superexchange coupling, J, between the localized spins. It is shown that the de-stabilization of the ferromagnetic ground state with increasing J leads to phase separation; the latter always preempts the spin-wave instability (softening of the m…
A one-step facile synthesis of submicrometer-sized hollow silver spheres (see Figure) has been achieved in aqueous solutions by using double-hydrophilic block copolymer (DHBC)-surfactant complex micelles as removable templates. The unique silver shell structures are candidates for both fundamental research and applica…
Advanced colloidal syntheses enable the preparation of monodisperse semiconductors and magnetic alloy nanocrystals. They can be further used as building blocks for the fabrication of ordered assemblies: two-dimensional and three-dimensional arrays and colloidal supercrystals. This article reviews our recent activities…
Among organic materials vitrification for many years was regarded mainly as a privilege of polymers. However, recently a lot of attention is paid to organic low molar mass compounds that readily form glasses above room temperature. Such compounds are called molecular glasses or amorphous molecular materials. Among the…
Polyaniline/multiwalled carbon nanotube composite films have been fabricated. It is shown that the nanotubes affect the free N–H environment and quinoid units along the polymer backbone. A 10-fold increase in conductivity is observed and elemental analysis indicates that the nanotubes compete with chloride ion during…
Soon after the discovery of carbon nanotubes, it was realized that the theoretically predicted mechanical properties of these interesting structures–including high strength, high stiffness, low density and structural perfection–could make them ideal for a wealth of technological applications. The experimental verifica…
235U fission products and their daughter radioisotopes sorption behavior on calcined hydrotalcite were studied through batch and dynamic experiments. Electrophoresis showed that 99Mo and 99mTc (the decay product of 99Mo) were present in the solution mainly as anions. 103Ru was found as neutral and anionic species and…
A B1–B2 transition in chalcogenides has been studied using three body potential approach upto 40 GPa. Phase transition pressures, volume collapses are found to be closed to experimental results. High phase transition pressures in CaSe and CaTe can be attributed to large cation anion differences. High-pressure elastic…
D-Aminoacylase is an attractive candidate for commercial production of D-amino acids through its catalysis in the zinc-assistant hydrolysis of N-acyl-D-amino acids. We report here the cloning, expression, and structural-based mutation of the D-aminoacylase from Alcaligenes faecalis DA1. A 1,007-bp PCR product amplifie…
We studied the fingerprint texture of homeotropic cholesteric liquid crystal (CLC) films. Parallel (360°) and antiparallel (180°) alignment treatments were adopted for these films such that the molecules at the boundaries had an approximately 1° pretilt angle to the substrate normal. The experimental results showed th…
Room temperature time-resolved luminescence measurements on single CdSe/ZnS quantum dots (QDs) are presented. Luminescence spectra were recorded over time periods of up to 30 min with a time resolution down to 6 ms. A clear 30–40 nm blue shift in the emission wavelength is observed for QDs in ambient air, before the l…
A neutron diffraction study over a wide Q-range (Qmax = 16 Å−1) has been made in order to analyze the change of the local order of triphenyl phosphite through the isothermal transformation between the supercooled liquid into the glacial state at different temperatures Ta. Direct evidence is given from the analysis of…
Abstract New polyurethanes with lactone groups in the pendants and main chains were synthesized by the polyaddition of two kinds of L ‐gulonolactone‐derived diols (2,3‐ O ‐isopropylidene‐ L ‐gulono‐1,4‐lactone and 5,6‐ O ‐isopropylidene‐ L ‐gulono‐1,4‐lactone) with hexamethylene diisocyanate and methyl ( S )‐2,6‐diiso…
Barium strontium titanate [(Ba,Sr)TiO 3 , BST] is an attractive material with a very high dielectric constant. However, the dielectric constant of BST films decreases with film thickness, which has become a serious problem for dynamic random access memory (DRAM) application. We found Fe doping of BST films to be remar…
ADVERTISEMENT RETURN TO ISSUEPREVNoteArchitectural Disparity Effects in the Morphology of Dendrimer−Linear Coil Diblock CopolymersDarrin J. Pochan, Lisa Pakstis, Elbert Huang, Craig Hawker, Robert Vestberg, and John PopleView Author Information Materials Science and Engineering and Delaware Biotechnology Institute, Un…
A new hydrocarbon/perfluorocarbon phase-switching strategy based on coordination of pyridyl-tagged molecules to a highly fluorinated dicopper-carboxylate complex possessing two accessible axial coordination sites is described. When a chloroform solution of the tetrapyridyl-substituted porphyrin 3 (0.1 mM, 2 mL) is lay…
Fracture resistance in biomineralized structures has been linked to the presence of proteins, some of which possess sequences that are associated with elastic behavior. One such protein superfamily, the Pro,Gly-rich sea urchin intracrystalline spicule matrix proteins, form protein-protein supramolecular assemblies tha…
By the first-principles calculations both for electronic structures and effective exchange constants, we investigate the stability of ferromagnetism of zinc-blende (ZB) type CrAs, and further examine a possibility of ferromagnetism of ZB type Mn M ( M =Si, Ge and Sn). ZB type CrAs, a half-metallic ferromagnet reported…