Materials Literature
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Tetrathiafulvalene analogues involving dihexyloxythiophene ( 1 ), ethylenedioxythiophene ( 2 ), and bis(3,4-dihexyloxy-2-thienyl)ethylene ( 3 ) as conjugating spacer and diversely substituted at the 1,3-dithiole ring (R) have been synthesized. Electronic absorption spectra show the expected decrease of HOMO−LUMO gap w…
The excess low-frequency $(1/f)$ electrical noise of three representative half-metallic oxides, ${\mathrm{CrO}}_{2},$ ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4},$ and ${\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3},$ has been studied as a function of the temperature (5--300 K) and a magnetic field (up to 12 T). In $…
The volumetric heat capacity and thermal conductivity of silicon-dioxide films prepared using low-pressure chemical vapor deposition (LPCVD) are measured. The measurements employ the 3ω technique, which is extended to determine the thermal conductivity anisotropy and volumetric heat capacity of thin dielectric films.…
The reflectance of highly reduced ${\mathrm{SrTiO}}_{3\ensuremath{-}x}$ has been studied in samples where the carrier concentration---or oxygen-vacancy density --- varies from about ${10}^{18}$ to ${10}^{21} {\mathrm{cm}}^{\ensuremath{-}3}.$ Several phonon modes are strongly influenced by oxygen-vacancy density. Oxyge…
Electron-paramagnetic-resonance (EPR) studies in radiation damaged diamond enriched to 5% ${}^{13}\mathrm{C}$ have resulted in the identification of the nearest-neighbor divacancy center. It is the isotopic enrichment, and consequent observation of ${}^{13}\mathrm{C}$ hyperfine lines, that has permitted the structure…
Polycarbonates were synthesized by ring-opening copolymerizations of trimethylene carbonate (TMC) with 1,2- O -isopropylidene- d -xylofuranose-3,5-cyclic carbonate (IPXTC). Subsequent deprotection of the ketal protecting groups gave controlled quantities of vicinal diol pendant groups. Studies of TMC/IPXTC copolymeriz…
Nanocomposites have been made by mixing soft particles (polymer latex) with hard particles (silica) in aqueous dispersions and extracting water to produce a dense film. Segregation between the two kinds of particles can be controlled, and even suppressed. The elongational modulus is strongly increased by such fillers…
Angular measurements of magnetic resonance are used to investigate the surface anisotropy field as well as the exchange anisotropy field in spherical MnFe2O4 magnetic nanoparticles as a function of temperature and particle diameter (D). The resonance field is a combination of angular dependent and angular independent…
Translational energy distributions of neutral potassium atoms are reported as a function of potassium coverage after uv-laser-induced desorption from well-characterized adsorption sites on an epitaxial film of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}(0001)/\mathrm{C}\mathrm{r}(110).$ Measurements using x-ray photoelectron s…
In the chromophore-quencher complex fac-[Re(Aqphen)(CO)(3)(py-PTZ)](+) (Aqphen is 12,17-dihydronaphtho[2,3-h]dipyrido[3,2-a:2',3'-c]-phenazine-12,17-dione; py-PTZ is 10-(4-picolyl)phenothiazine), Aqphen is a dppz derivative, containing a pendant quinone acceptor at the terminus of a rigid ligand framework. This introd…
In situ synchrotron radiation measurements of porous silicon (PS) strain have been performed during ultrahigh vacuum (UHV) thermal annealing. For a p+ sample, the initial lattice expansion shifts toward a contraction above 270 °C in relation with hydrogen desorption. For a p− sample, the strain variation is similar to…
The combined effect of shape and dielectric mismatch between dot and matrix on several electronic properties of semiconductor quantum dots have been studied. In particular, the electronic properties of spherical and cubic quantum dots that have been analyzed are the integrated density of states, the polarization self-…
In this paper we present the optical properties of various structural models for $a\ensuremath{-}\mathrm{Si}$ and $a\ensuremath{-}\mathrm{S}\mathrm{i}:\mathrm{H}.$ We discuss how topological disorder, hydrogen content, and different types of defects (dangling bonds and floating bonds) influence the shape of the optica…
Pseudomonas oleovorans contains an isomerase which catalyzes the cis-trans conversion of the abundant unsaturated membrane fatty acids 9-cis-hexadecenoic acid (palmitoleic acid) and 11-cis-octadecenoic acid (vaccenic acid). We purified the isomerase from the periplasmic fraction of Pseudomonas oleovorans. The molecula…
Molecular dynamics simulations are carried out to study the structure formation of 100 short chain molecules, each of which consists of 20 CH2 groups. Our simulations show that the orientationally ordered structure is formed from a random configuration by quenching. The global orientational order starts to increase su…
Intrinsic electrical properties of Au/Nb-doped SrTiO3(001) (STO:Nb) Schottky junctions, fabricated using a proper surface treatment of the STO:Nb and in situ deposition of Au, were investigated in detail. Current–voltage characteristics and photocurrent–wavelength characteristics have shown a temperature-dependent and…
This paper deals with the adsorption states of ammonia on both the Brönsted and Lewis acid sites of V 2 O 5 (010) surface using the periodic boundary first-principles density functional (DFT) calculations. The calculated results indicate that ammonia adsorption takes place on both the Brönsted and Lewis sites of V 2 O…
Angle-resolved core-level photoemission has been utilized to study the surfaces of crystalline thin films of manganite ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ ($x=0.1$ and 0.35). It is found that both the surface termination and Ca surface concentration depend on the bulk Ca concentration…
CdS thin films are grown by photochemical deposition from an aqueous solution and characterized by x-ray diffraction (XRD), Raman spectroscopy, photoluminescence measurement, and optical transmission spectroscopy. The films are deposited at room temperature and annealed at temperatures up to 500 °C. The as-deposited f…
The local orbital extension of the linearized augmented plane wave (LAPW+LO) method within the general gradient approximation was used to determine structural and ferroelectric properties of tetragonal ${\mathrm{PbTiO}}_{3}$ (PT), and two chemically ordered ${\mathrm{PbZr}}_{1/2}{\mathrm{Ti}}_{1/2}{\mathrm{O}}_{3}$ (P…