Materials Literature
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The reactivity of the [alpha-SiW(11)O(39)](8-) monovacant polyoxometalate with lanthanide has been investigated for four different trivalent rare-earth cations (Ln = Nd(III), Eu(III), Gd(III), Yb(III)). The crystal structures of KCs(4)[Yb(alpha-SiW(11)O(39))(H(2)O)(2)] x 24H(2)O (1), K(0.5)Nd(0.5)[Nd(2)(alpha-SiW(11)O…
The additive dose, T m ( E a )– T stop , repeated initial rise, variable heating rate and computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks and kinetic parameters (kinetic orders b , activation energy E a and attempt-to-escape frequency s ) associated with the thermolumine…
The evolution and physicochemical characteristics of CeO 2 −ZrO 2 and V 2 O 5 /CeO 2 −ZrO 2 samples under the influence of thermal treatments from 773 to 1073 K were investigated using X-ray diffraction (XRD), BET surface area, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The CeO 2 −ZrO 2 mixed oxid…
The thermal conductivity of the spin-1/2 chain cuprate BaCu2Si2O7 was measured along different crystallographic directions in the temperature region between 0.5 and 300 K. The thermal conductivity along the chain direction considerably exceeds that along perpendicular directions. Near the antiferromagnetic transition…
With 780-nm, 250-fs laser pulses, ultrafast optical nonlinearity has been observed in a series of thin films containing PMMA-TiO2 nanocomposites, which are synthesized by a simple technique of in-situ sol-gel/polymerization. The best figures of merit are found in one of the films prepared with a 60% weight percentage…
We report here noncollinear magnetic configurations in the Heusler alloys ${\mathrm{Ni}}_{2}\mathrm{MnGa}$ and ${\mathrm{Ni}}_{2}\mathrm{MnAl}$ which are interesting in the context of the magnetic shape memory effect. The total energies for different spin spirals are calculated and the ground-state magnetic structures…
The various approximations used in the construction of a first-principles effective Hamiltonian for ${\mathrm{BaTiO}}_{3},$ and their effects on the calculated transition temperatures, are discussed. An effective Hamiltonian for ${\mathrm{BaTiO}}_{3}$ is constructed not from first-principles calculations, but from the…
We calculate from first principles the electronic structure, relaxation and magnetic moments in small Fe particles, applying the numerical local orbitals method in combination with norm-conserving pseudopotentials. The accuracy of the method in describing elastic properties and magnetic phase diagrams is tested by com…
In a recent publication [D. P. Varn, G. S. Canright, and J. P. Crutchfield, Phys. Rev. B {\bf 66}:17, 156 (2002)] we introduced a new technique for discovering and describing planar disorder in close-packed structures (CPSs) directly from their diffraction spectra. Here we provide the theoretical development behind th…
In the previous paper of this series [D. P. Varn, G. S. Canright, and J. P. Crutchfield, Physical Review B, submitted] we detailed a procedure--epsilon-machine spectral reconstruction--to discover and analyze patterns and disorder in close-packed structures as revealed in x-ray diffraction spectra. We argued that this…
Alkyllithium reagents may be used to attach alkyl groups to the sidewalls of fluoro nanotubes. Thermal gravimetric analysis combined with UV-vis-Nir spectroscopy has been used to provide a quantitative measure of the degree of functionalization. SWNTs prepared using the HiPco process exhibit a higher degree of alkylat…
Scanning X-ray microdiffraction (microSXRD) combines the use of high-brilliance synchrotron sources with the latest achromatic X-ray focusing optics and fast large-area two-dimensional-detector technology. Using white beams or a combination of white and monochromatic beams, this technique allows for the orientation an…
The structural development of a segmented poly(urethane−urea) (PUU) elastomer containing a low concentration of hard segment during deformation was studied by simultaneous mechanical and optical measurements (rheooptical techniques). Specifically, in-situ wide-angle X-ray diffraction and small-angle X-ray scattering u…
Physicochemical properties of a homogeneous series of chitosans with different degrees of acetylation and almost the same degree of polymerization were investigated in an ammonium acetate buffer. Techniques such as interferometry, static light scattering (in batch or coupled on line with a chromatographic system), and…
The thermal conductance of interfaces between epitaxial TiN and single crystal oxides is measured at temperatures between 79.4 and 294 K using time-domain thermoreflectance. The analysis method relies on the ratio of the in-phase and out-of-phase signals of the lock-in amplifier for more accurate data analysis. The va…
Current theories suggest that multiwalled nanotubes may form through a scrolling mechanism ([1][1], [2][2]). The concept that scrolling could lead to nanotube-like structures ([3][3]) inspired us to extend our recent work on making colloidal suspensions of layered compounds ([4][4]) to graphite.
Superhydrophobic surfaces are generally made by controlling the surface chemistry and surface roughness of various expensive materials, which are then applied by means of complex time-consuming processes. We describe a simple and inexpensive method for forming a superhydrophobic coating using polypropylene (a simple p…
Impregnation of hypercrosslinked polystyrene (HPS) with tetrahydrofuran (THF) or methanol solutions containing platinic acid resulted in the formation of Pt(II) complexes within the nanocavities of HPS. The highest selectivity (98% at 100% conversion) measured during the catalytic oxidation of L-sorbose in water was o…
Abstract Systematische Studien zur Synthese neuer Erdalkalimetallthioborate und zum Kationeneinfluß auf die Strukturen ternärer Verbindungen dieses Typs führten zu den Strontiumthioboraten Sr 3 (BS 3 ) 2 und Sr 3 (B 3 S 6 ) 2 . Die neuen Verbindungen wurden aus Strontiumsulfid, amorphem Bor und Schwefel in Festkörperr…
Ein molekularer Magnet mit Tc=3.5 K wurde durch Umsetzung von GdCl3⋅6 H2O mit Li[TCNQ] (TCNQ=7,7,8,8-Tetracyanchinodimethan) erhalten. In der Titelverbindung liegen laut Einkristall-Röntgenbeugung anionische und kationische (siehe Bild) Netze aus Gd, TCNQ und H2O in unterschiedlichen Verhältnissen nebeneinander vor.