Materials Literature
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We studied the electronic structure of ${\mathrm{CaMnO}}_{x}$ $(2.66<~x<~3.00)$ using x-ray photoemission and O $1s$ x-ray-absorption spectroscopy. Analyzing the spectra of the two end members with the configuration-interaction cluster model, we have determined all the main parameters of the electronic structure…
The growth of thin silicate−organic films at the air−water interface of surfactant solutions has been studied in situ by X-ray and neutron reflectivity to a resolution of ca. 5 Å. Surfactant in the solution and the air−water interface itself are involved in directing the growth and final structure of the films. Hexade…
We have observed a significant change of absorption spectrum in the visible region by the irradiation of an intense laser pulse in a double-exchange ferromagnet ${(\mathrm{N}\mathrm{d}}_{0.5}{\mathrm{Sm}}_{0.5}{)}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ $(x=0.4)$ thin film. In the ferromagnetic state, t…
We present atomically resolved scanning tunneling microscopy images of single-wall carbon nanotubes (SWNT's) embedded in a crystalline nanotube rope. Although they may be interpreted as of a chiral nanotube, the images are more consistently explained as an achiral armchair tube with a quenched twist distortion. The ex…
The line shape of the one phonon Raman peak has been used extensively in the literature to estimate the crystallite size in porous silicon. However it has been shown that the line shape obtained on top surface experiments depends on the excitation wavelength. Because the porosity depends on depth, previous results are…
The Mooney scorch times of three rubber blends [epoxidized natural rubber (ENR) 50/SMR L, ENR 50/styrene butadiene rubber (SBR), and Standard Malaysian Rubber SMR L/SBR] were studied in the temperature range of 120–160°C using an automatic Mooney viscometer. N-Cyclohexyl-2-benzothiazyl sulfenamide was used as the acce…
Alternating current impedance, Fourier transform Raman/infrared (IR), and luminescence excitation (continuous and time-resolved) measurements have been conducted on solutions of poly(propylene glycol) (MW 4000) complexed with Eu[N(CF3SO2)2]3 salt, EuTFSI3, along with differential scanning calorimetry (DSC) studies. Fr…
To identify key parameters which influence the efficiency of nonenzymatic template-directed oligonucleotide reactions, a kinetic study of oligoguanylate synthesis on a polycytidylate (poly(C)) template has been performed. This oligomerization is satisfactorily described by three kinetic processes: (i) dimerization to…
We report measurements of the resistivity, thermopower, thermal conductivity, Hall coefficient, and magnetic susceptibility of ${\mathrm{RuAl}}_{2}$ over a wide temperature range. Room-temperature sound velocity measurements are also reported. We find that at low temperature ${\mathrm{RuAl}}_{2}$ behaves as a low carr…
Iron samples of different thicknesses have been submitted to laser shocks of short duration. Transmitted wave measurements have been performed by means of polymeric piezoelectric transducers. The records indicate a decrease of the elastic precursor amplitude with increasing propagation distance, as well as a stress re…
Nonlinear optical properties of a fixed molecular dimer, 2,2′-diamino-7,7′-dinitro9,9′-spirobifluorene (ANSF), have been investigated in solution by the degenerate four-wave mixing technique. It has been observed that the orientationally averaged second molecular hyperpolarizability of ANSF in THF is enhanced ten time…
Dynamically vulcanized poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) thermoplastic elastomers (TPEs) were prepared with a Brabender plasticorder coupled with a mixing attachment by melt mixing. The blends were prepared at 150°C at a rotor speed of 50 rpm. Curatives concentration was steadily increased from…
It has recently been shown that well-ordered ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}(111)$ films can be prepared epitaxially on clean Pt(111) surfaces; various techniques have indicated that these multilayer films are chemically identical to bulk single crystals. We have studied the electronic structure of such an ordered…
Angle-resolved photoemission spectroscopy (ARPES) measurements on ${\mathrm{NiS}}_{2\ensuremath{-}x}{\mathrm{Se}}_{x}$ single crystals show the evolution of a narrow band near the Fermi level, which develops in the vicinity of the correlation-driven metal-insulator transition. To model the metal-insulator transition,…
We show that epd (gapB) mutants lacking an erythrose 4-phosphate (E4P) dehydrogenase are impaired for growth on some media and contain less pyridoxal 5'-phosphate (PLP) and pyridoxamine 5'-phosphate (PMP) than their epd+ parent. In contrast to a previous report, we found that gapA epd double mutants lacking the glycer…
The magnitudes and orientations of the principal elements of the 15 N chemical shift and 1 H− 15 N dipolar coupling interaction tensors pertaining to the glycine residue in 15 N -acetyl glycine (NAG) and [ 15 N-Gly]collagen were determined by the analysis of one-dimensional dipolar chemical shift powder patterns. A on…
Isothermal crystallizations from the melt of samples of syndiotactic polypropylene having different degrees of syndiotacticity have been performed. The thermal behavior and the structural features of the melt-crystallized samples have been analyzed by differential scanning calorimetry and X-ray diffraction. According…
A disordered three-dimensional perovskite phase SrTa2-xNbxO6 (x = 0, 0.2, 0.4) is formed by topochemical dehydration of acid-exchanged Ruddelsden Popper compounds K2SrTa2-xNbxO7. The metastable perovskite is a stoichiometric precursor to the structurally unrelated, stable tetragonal tungsten bronze phase. Dehydration…
Chitosan fibers were wet spun from a 6% by weight chitosan in 3% by volume acetic acid solution. The fibers were collected as a 20 filament yarn intended for use as a chaff substrate. The yarn had to be sufficiently dry following spinning to allow for winding and subsequent separation of the filaments. Drying of the y…
Temperature dependence of absorption spectra for thin films of doped manganites ${R}_{0.6}{\mathrm{Sr}}_{0.4}{\mathrm{MnO}}_{3},$ where $R$ is a rare-earth atom, has been investigated by systematically changing the averaged ionic radius $〈{r}_{A}〉$ of perovskite $A$ site. We have observed a specific absorption band at…