Materials Literature
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Barium gallogermanate glasses are a relatively new family of glasses with tremendous potential for both fiber and bulk optical applications. This ternary system has a broad region of glass forming ability, excellent stability with respect to crystallization, and transmission beyond 5 micrometers . This paper reports t…
The affects of iron on the structure, physical, and optical properties of several iron phosphate and sodium-iron phosphate glasses were investigated using x-ray photoelectron spectroscopy (XPS), Mossbauer spectroscopy, and infrared spectroscopy (IR). Archimedes method, differential scanning colorimeter and Able refrac…
About 200 glasses were made by compressing the hard sphere fluid. The location of the glass transition is not measurably changed when the rate at which the fluid is compressed through the transition is varied by a factor of 500. There is small variance in the properties of the glasses but no statistically significant…
We present 13 C NMR measurements carried out under pressure and between 10 and 300 K on a single crystal of the organic superconductor κ-(ET) 2 Cu[N(CN) 2 ]Br. Under pressure, the large variation of the Knight shift is interpreted as the presence of electronic correlations. We estimate the U/W ratio to be of order uni…
Abstract This book clearly illustrates the limitations of using chemical thermodynamics to describe chemical phenomena in soils--especially with regard to kinetics and molecular mechanisms--and proposes that the quantitative description of soils is not complete without adequate characterization of the rates of the che…
Triglycine sulfate (TGS) is one of the most comprehensively studied ferroelectric materials for infrared detecting devices. The discovery of new materials with more attractive properties together with a growing requirement for uncooled thermal detectors, having better performance than the thermistor bolometers, has re…
Density, DC conductivity and 11B wide-line NMR investigations have been carried out for xFe2O3-(50-x)PbO-50B2O3 glasses (0<or=x<or=20 mol%). The NMR spectra indicated the formation of non-bridging oxygen ions in the borate network upon introducing Fe2O3. The DC conductivity and the activation energy for conduction cha…
New experimental results on Raman scattering from porous silicon and silicon and gallium arsenide nanocrystals are reported. In all of these systems, almost all vibrational modes become Raman active and are remarkably soft. A carrier-induced strain model is proposed to explain the optical properties of these nanocryst…
Abstract The morphology and mechanical properties of polyamide‐based blends prepared in single and corotating twin‐screw extruders were compared using transmission electron microscopy (TEM) techniques. Reactive polyamide blends with SEBS‐ g ‐MA (a maleated styrenic triblock copolymer with ethylene–butvlene midblocks),…
Low temperature annealing of insulatinglike AlPdRe icosahedral-quasicrystalline (iqc) samples has led to unexpected large changes in their transport properties, with resistivities at 0.45 K increasing from \ensuremath{\sim}1 to > 10 \ensuremath{\Omega} cm, but their electronic structure is apparently unaffected. Th…
We describe the preparation, characterization, and use of ‘‘plastic’’ infrared polarizers that consist of electrically conductive polyaniline blends with common bulk polymers such as poly(acrylonitrile), polyethylene, and poly(vinylalcohol). It is shown that uniaxially oriented blends of protonated polyaniline in, for…
We report on experimental valence and conduction electronic distributions of quasicrystalline Al-Mn-Pd alloys probed using the soft x-ray emission and absorption spectroscopy techniques. The various partial distributions are adjusted in the binding energy scale in order to investigate the electronic interactions chara…
Abstract Microwave transmission, reflection, and absorption behavior and the shielding effectiveness of electrochemically synthesized polypyrrole films with dc conductivities ranging from 0.001 to 50 S/cm are presented. Results show that the electrical conductivity of the doped polypyrrole films has a significant effe…
Molecular structures can perform diverse functions . Tailored bolaamphiphiles were used to prepare vesicles containing redox‐active centers or (chiral) binding sites for guests, as well as aggregates. In addition, monomeric and polymeric bolaamphiphiles can disrupt membranes. RNA‐based bolaamphiphiles of this type may…
We report the growth of epitaxial SrxBa1−xNb2O6 (SBN) thin films by pulsed laser deposition. The films were grown on (100) MgO substrates with thicknesses in the range 200–400 nm. Rutherford backscattering analysis showed that the films have stoichiometric composition identical to the target material. X-ray diffractio…
For 30 diamond- and zincblende-structure semiconductors, the bond length d, bond polarity alpha p , bulk modulus B, elastic shear constants (c 11 -c 12 )/2 and c 44 , bond-stretching force constant alpha , bond-bending force constant beta , internal displacement parameter zeta , effective atomic charge Z*, transfer pa…
Dynamic processes in liquid propylene glycol and two of its oligomers inside the \ensuremath{\cong} 100 \AA{} pores of controlled porous glasses have been investigated as a function of temperature by dielectric spectroscopy. We find that geometrical restriction results in retardation and broadening of the inherent $\e…
We report the observation of giant magnetoresistance near room temperature in ferromagnetic films of La1−xSrxMnOz for 0.16≤x≤0.33. For B=5 T, the maximum magnetoresistance ratio [R(0)−R(B)]/R(0) of an annealed film is 60% at 260 K for x=0.2, and 35% at 330 K for x=0.33. Annealed films have higher Curie temperature (Tc…
Abstract In der Übergangsmetallchemie gibt es eine Klasse von Komplexverbindungen, bei denen eine Temperaturerniedrigung einen Wechsel im Spinzustand des Zentralatoms vom High‐Spin‐ in den Low‐Spin‐Zustand bewirkt. Dabei ändern sich die magnetischen und optischen Eigenschaften, über die der thermische Spinübergang (au…
The elastic moduli directly reflect bonding strength and structure. Usually these factors can be only slightly modified within a given material, but in amorphous carbon films large variations of Young's modulus from less than 100 up to more than 500 GPa are found. This can be attributed mainly to the varying fraction…