Materials Literature
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The substitution of molybdenum for manganese has been studied in the CaMn1−xMoxO3 series for 0 ≤ x ≤ 0.15. We establish a structural and magnetic diagram combining electron microscopy, neutron diffraction and magnetic susceptibility measurements. Four regions have been evidenced versus composition (x) and temperature.…
Isothermal spherulite growth rates were measured over a sufficient range of undercoolings, Δ T, for a narrow linear polyethylene fraction M = 70 300 (70.3K), polydispersity 1.12, such that the fraction exhibited all three growth regimes as crystallized from the subcooled melt. The I−II transition occurred at Δ T I - I…
A hollow spherical cage made of nested single-walled carbon nanotubes is constructed using self-assembly techniques. Nanotubes are first adsorbed onto amine-terminated silica gels in solution. Then, the drying and readsorption cycle grow the nanotube nest layer-by-layer. Finally, silica gels are etched away to give ho…
We study thermodynamic and dynamic properties of a rigid model of the fragile glass-forming liquid orthoterphenyl. This model, introduced by Lewis and Wahnström in 1993, collapses each phenyl ring to a single interaction site; the intermolecular site-site interactions are described by the Lennard-Jones potential whose…
We report a detailed study of $^{11}$B and $^{27}$Al NMR spin-lattice relaxation rates ($1/T_1$), as well as of $^{27}$Al Knight shift (K) of Mg$_{1-x}$Al$_x$B$_2$, $0\leq x\leq 1$. The obtained ($1/T_1T$) and K vs. x plots are in excellent agreement with ab initio calculations. This asserts experimentally the predict…
Spins based in silicon provide one of the most promising architectures for quantum computing. Quantum dots are an inherently scalable technology. Here, we combine these two concepts into a workable design for a silicon-germanium quantum bit. The novel structure incorporates vertical and lateral tunneling, provides con…
The phenomenon of potential sputtering of ultra-thin Pt films due to impact of 20 keV highly charged $Ar^{q+}$ (q = 3 - 8) ions has been investigated. The results show enhanced erosion of the Pt film with the increase of potential energy of the Ar projectile.
We have used optically excited ultrashort electrical pulses to measure the magnetoplasmon resonance of a two-dimensional electron gas formed in an AlGaAs/GaAs heterostructure at frequencies up to 200 gigahertz. This is accomplished by incorporating the sample into a guided wave probe operating in a pumped (^{3}He) sys…
We report on a systematic study of strain effects on the transport properties and the ferromagnetic transition temperature ${T}_{c}$ of high-quality ${\mathrm{La}}_{0.9}{\mathrm{Sr}}_{0.1}{\mathrm{MnO}}_{3}$ thin films epitaxially grown on (100) ${\mathrm{SrTiO}}_{3}$ substrates. Both the magnetization and the resisti…
A numerical implementation of self-consistent mean-field theory for the structural phase behavior of block copolymers is proposed. Our scheme does not require a priori assumptions of the underlying mesoscopic symmetries. The method potentially enables us to characterize, with high accuracy, the structural phase diagra…
Alternating adsorption of polyethyleneimine−metal ion complexes and polyanions results in the formation of multilayered polyelectrolyte films. Postdeposition reduction of the metal ions by heating or exposure to NaBH 4 then yields composite films containing metal nanoparticles. UV/visible spectroscopy and transmission…
This paper is one of a series exploring simple approaches for the estimation of lattice energy of ionic materials, avoiding elaborate computation. The readily accessible, frequently reported, and easily measurable (requiring only small quantities of inorganic material) property of density, rho(m), is related, as a rec…
Thermal and photochemical reactions of nitroaquacobalt(III) tetraphenylporphyrin, (NO(2))(H(2)O)Co(III)TPP, have been investigated in toluene solutions containing triphenylphosphine, P phi(3). It is found that Pphi(3) thermally abstracts an oxygen atom from the NO(2) moiety of (NO(2))(H(2)O)Co(III)TPP with a rate cons…
A novel sol−gel process has been developed for the synthesis of amorphous silica−aluminas with controlled mesopore distribution without the use of organic templating agents, e.g., surfactant molecules. Ultrasonic treatment during the synthesis enables production of precursor sols with narrow particle size distribution…
Two different species of CdTe nanocrystals stabilized with thioacids or aminothiols have been prepared. These were used in order to build up a superstructure by covalent binding via an amide bond using water soluble carbodiimides acting as a mediating agent. The resulting structure has been characterized by UV/vis abs…
Researchers have recently questioned the role hydroxylated prolines play in stabilizing the collagen triple helix. To address these issues, we have developed new molecular mechanics parameters for the simulation of peptides containing 4(R)-fluoroproline (Flp), 4(R)-hydroxyproline (Hyp), and 4(R)-aminoproline (Amp). Si…
The new amphiphile 1,4-diketo-5-methyl-2-(11-undecyl sulfate sodium salt)-3-(4-chlor)phenyl-6-phenylpyrrolo-[3,4-c]-pyrrole ( Na-1 ) is described, carrying the diketopyrrolopyrrole chromophore in the hydrophobic part. An aqueous solution of Na-1 exhibits an orange color with an absorption maximum at 475 nm and a red-o…
Dynamic contact angle studies on self-assembled thin films from C 7 F 15 CH 2 OCH 2 CH 2 CH 2 SiCl 3 reveal a range of interesting behavior. Solution-based processing conditions have been identified that allow preparation of essentially monolayer films on quartz exhibiting water adv/rec contact angles of 119/104 ± 2°…
We present molecular dynamics simulations on 1,4-polybutadiene comparing the dynamics of melt chains between chemically realistic models and a freely rotating chain version of one of the models. These models exhibit the same liquid structure, as measured by the structure factor, and meso- to large-scale chain structur…
BACKGROUND: Although inhibition of neointimal hyperplasia by cell cycle gene blockade therapy results in improved endothelial cell function in experimental vein grafts, little is known either about endothelial healing immediately after vein grafting or about the effect of this therapy on the healing process. METHODS A…