Materials Literature
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We report a computer simulation study of systems of perfectly aligned molecules interacting through the Gay–Berne (GB) potential model for two different values of the molecular anisotropy parameter κ, namely 3 and 4.4. The models are appropriate to gauge the effects of strong aligning fields on the thermodynamics and…
The luminescence characteristics of europium-ion activated Y3Al5O12 (YAG:Eu3+) phosphors prepared via a sol-gel process were investigated in the vacuum ultraviolet (VUV) region using synchrotron radiation. An intense red emission due to D05→F17 transition of Eu3+ ions is produced under excitation at 147nm. The intensi…
The hydrogen-alkali metal bond is simple and archetypal, and thus an ideal model for studying the nature of highly polar element-metal bonds. Thus, we have theoretically explored the alkali metal hydride monomers, HM, and (distorted) cubic tetramers, (HM)4, with M = Li, Na, K, and Rb, using density functional theory (…
A simple procedure to detect light polarization by use of crossed polarization gratings in photo-cross-linkable liquid crystals is presented. Crossed polarization gratings consisting of four anisotropic gratings with different grating vectors were designed according to the theoretical expectation obtained on the basis…
Abstract The dynamic glass transition and the dilatometric glass transition temperature are simultaneously characterized in thin films of hyperbranched aromatic polyesters by broadband dielectric spectroscopy and capacitive scanning dilatometry. A diverging thickness dependence is detected: while the temperature posit…
[structure: see text] Three strands of natural collagen are linked by covalent bonds prior to their folding into a triple helix. We report on a synthetic collagen in which the strands are pendent on a rigid macrocyclic scaffold of C(3) symmetry. The scaffold confers substantial conformational stability upon the collag…
The synthesis of 5,10,15,20-tetraphenyl-2-thia-21-carbaporphyrin [S-confused thiaporphyrin, (SCPH)H] was optimized. The formation of the phlorin was detected, which was saturated at the meso carbon adjacent to thiophene. Phlorin converted readily to (SCPH)H in the final oxidation process. Insertion of cadmium(II) and…
Linear optical properties of two types of poly(phenylquinoxaline) (PPQ) are studied by multiwavelength prism coupling technique and optical absorption spectroscopy. Surface roughness measurements are done using atomic force microscopy. PPQs form smooth films of high optical quality having refractive indices above 1.7…
Reminiscent of a snowflake: The dimer of a hydroxy-substituted oligosilane dendrimer (see picture, left; Si yellow, C green, H white, O red) is remarkably stable according to IR spectroscopy and DFT calculations. Strong intermolecular hydrogen bonds are not only the glue that holds the “silicon snowflake” together, bu…
Gold-nanopillar arrays are patterned at predefined positions on a silicon substrate (see figure; scale bar=600 nm). The technique is based on the electrodeposition of gold into nanoporous alumina templates. Prior to anodization the thin aluminum film is indented via an imprinting procedure to define the spots for nano…
Mg 2 Ni H 4 thin films have been prepared by activated reactive evaporation in a molecular beam epitaxy system equipped with an atomic hydrogen source. The optical reflection spectra and the resistivity of the films are measured in situ during deposition. In situ grown Mg2NiH4 appears to be stable in vacuum due to the…
We report the immobilization of a fulleropyrrolidine, bearing a dec-9-ynyl functionality, on silicon surfaces through a thermal hydrosilylation protocol. Contact angle measurements on porous silicon (PS) surfaces reveal an unusual dependence of the angle with the PS roughness that apparently contradicts Wenzel's formu…
The spatial structure of a stilbenoid dendrimer is investigated by small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) in dilute solution. All measurements are performed in toluene. The dendrimer consists of a stilbenoid scaffold with appended hexyloxy chains. SAXS is mainly sensitive to the…
Palladium nanoparticles have been successfully incorporated into a porous diblock copolymer template using a novel technique. An ordered bicontinuous double gyroid phase was created from poly(isoprene)- block -poly(2-vinylpyridine). The poly(isoprene) matrix of this structure was subsequently removed by ozonolysis, cr…
Reversible martensitic phase transformations in a partially disordered Ni–Al alloy within the composition range from 60to65at.% of Ni are investigated using molecular dynamics simulation. During a complete temperature cycle a wide hysteresis in enthalpy, volume, and shape of the simulated crystals is observed. The tem…
A composite material comprising randomly distributed spherical particles of two different isotropic dielectric-magnetic materials is homogenized using the second-order strong-property-fluctuation theory in the long-wavelength approximation. Whereas neither of the two constituent materials by itself supports plane wave…
Ferroelectric phase shifter is preferred to be used in paraelectric phase due to the demand of low loss. Dielectric response of polar nanoregions was analyzed in the present study, including their characteristics and contributions both to dielectric polarization and tunability. The corresponding dielectric constant of…
Commercial volatile organic compound (VOC) combustion catalysts, including V−W−Ti−O, Mn−Al−O, and Mn−W−Al−O, that operate well below 600 K produce only dehydrochlorination of 2-chloropropane to HCl and propylene. Catalytic materials based on chromia aerogel, prepared in this study, yielded complete combustion with abo…
Quasiamorphous Ag films of thicknesses ranging from 5to30nm were prepared using rf magnetron sputtering technique and their controlled iodization was carried out for selected durations in the range of 15min–60h at room temperature. As deposited Ag and iodized films were characterized using x-ray diffraction (XRD), ato…
The effect of Cu substitution on the structural and magnetic properties of $\mathrm{Tb}{\mathrm{Ni}}_{5\ensuremath{-}x}{\mathrm{Cu}}_{x}$ $(x=0,0.5,1.0,1.5,2.0)$ have been investigated by x-ray diffraction, magnetization measurements and neutron powder and single crystal diffraction. The electronic and the magnetic st…