Materials Literature
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PbSe nanocrystal colloids exhibit a well-defined excitonic structure with the lowest energy exciton tuning from 0.5 to 1 eV, as a function of size. Band-edge fluorescence is observed from 1.2 to 2 μm with a small Stokes shift, sub-μs lifetime, and near-unity quantum yield. Upon pumping at 1.064 μm, the first exciton d…
For years scientists turned to the CRC Handbook of Laser Science & Technology for reliable data on optical materials. Out of print for several years, that standard-setting work now has a successor: the Handbook of Optical Materials.This new handbook is an authoritative compilation of the physical properties of materia…
In response to recent nuclear-magnetic-resonance (NMR) measurements on the molecular cluster $\mathrm{M}{\mathrm{n}}_{\mathrm{12}}{\mathrm{O}}_{\mathrm{12}}$ acetate, we study the nuclear spin-lattice relaxation rate $1/{T}_{1}$, developing a modified spin-wave theory. Our microscopic new approach, which is distinct f…
The optical properties of anisotropic quantum dots with ellipsoidal shape are investigated and discussed as a function of the dot aspect ratio. The energy spectrum (ground and many excited states) is calculated and analyzed in comparison with the spherical quantum dot. The optical matrix elements in the dipole approxi…
Expression of Escherichia coli open reading frame yfcX is shown to be required for medium-chain-length polyhydroxyalkanoate (PHA(MCL)) formation from fatty acids in an E. coli fadB mutant. The open reading frame encodes a protein, YfcX, with significant similarity to the large subunit of multifunctional beta-oxidation…
Summary The morphology and distribution of six benthic colonial diatoms were investigated from the perspective of fractal geometry and stream ecology to test whether colonial complexity of benthic diatoms is associated with a tolerance to environmental variability, that is, if a random force, such as the unpredictabil…
The Azotobacter vinelandii phbBAC genes encode the enzymes for poly-beta-hydroxybutyrate (PHB) synthesis. The phbR gene, which is located upstream of and in the opposite direction of phbBAC, encodes PhbR, a transcriptional activator which is a member of the AraC family of activators. Here we report that a mutation in…
We have considered theoretically the main properties of layered periodical structures [one-dimensional photonic band gap (PBG) structures] that include layers of so-called backward-wave material (BW), whose both permittivity and permeability are negative. Each period consists of one layer of a usual material and one l…
Using theoretical models, we undertake the first investigation into the rich behavior that emerges when binary particle mixtures are blended with microphase-separating copolymers. We isolate an example of coupled self-assembly in such materials, where the system undergoes a nanoscale ordering of the particles along wi…
Abstract Fluorohectorites were rendered organophilic through the cation exchange of sodium intergallery cations for protonated monoamine, diamine, and triamine oligopropyleneoxides and octadecylamine, benzylamine, and adducts of octadecylamine and benzylamine with diglycidyl ether of bisphenol A (DGEBA). The influence…
Single element quasicrystalline monolayers were prepared by deposition of antimony and bismuth on the fivefold surface of icosahedral ${\mathrm{A}\mathrm{l}}_{71.5}{\mathrm{P}\mathrm{d}}_{21}{\mathrm{M}\mathrm{n}}_{8.5}$ and the tenfold surface of decagonal ${\mathrm{A}\mathrm{l}}_{71.8}{\mathrm{N}\mathrm{i}}_{14.8}{\…
We show the existence of three well defined time scales in the dynamics of wormlike micelles after a step between two shear rates on the stress plateau. These time scales are compatible with the presence of a structured interface between bands of different viscosities and correspond to the isotropic band destabilizati…
We explore the possibility of extracting information about lattice dynamics in simple crystal structures from the neutron pair-density function (PDF) through inverse data analysis. Contrary to the claims by Dimitrov, Louca, and Roeder [Phys.Rev. B 60, 6204 (1999)], and in agreement with recent work by Reichardt and Pi…
Many structural transformations involve a group-nonsubgroup relationship between the initial and transformed phases, and hence are beyond the purview of conventional Landau theory. We utilize a systematic and robust methodology to describe such reconstructive martensitic transformations by coupling group-theoretical a…
In this work we analyze the room-temperature linewidth for several Raman features (i.e., the radial breathing mode, the G band, the D band, and the ${G}^{\ensuremath{'}}$ band) observed for individual isolated single-wall carbon nanotubes (SWNTs). Temperature-dependent measurements on SWNT bundles and isolated SWNTs s…
Indium gadolinium digermanium heptaoxide, In(1.08)Gd(0.92)Ge(2)O(7), with a thortveitite-type structure, has been prepared as a polycrystalline powder material by a high-temperature solid-state reaction. As in the mineral thortveitite, the crystal structure belongs to the monoclinic system, with space group C2/m (No.…
The aqueous synthesis and electrochemical properties of the new nanocrystalline material M 1 - x V 3 O 8 - y F z · n H 2 O (M = NH 4, K; x ≈ 0.0−0.2; y ≈ 0.0−0.2; z ≈ 0.1−0.2; n ≈ 1) are described. This material is easily prepared by precipitation from aqueous HF-acidified ammonium or potassium vanadate solutions. M 1…
The synthesis of silicon nanowires containing erbium in a discrete layered structure has been achieved. These wires are prepared by the pyrolysis of silane and a volatile erbium complex on a gold catalyst surface, with the relative size of the wire and sample crystallinity affected by the timing in which erbium is int…
One efficient strategy for creating nanostructures on surfaces is to use the catalytic properties of a surface molecule. This strategy benefits from the amplification and chemical specificity inherent in catalysis. We describe a demonstration of the key step of such a strategy: the surface trapping of a product genera…
Novel lamellar mesophases which are quite distinct from conventional smectic mesophases were obtained with a bolaamphiphilic triblock molecule composed of a rigid biphenyl core, two polar 2,3-dihydroxypropoxy groups in the terminal 4- and 4'-positions, and a semiperfluorinated chain [O(CH2)6C10F21] in the lateral 3-po…