Materials Literature
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Tunneling of Bloch electrons through a vacuum barrier introduces new physical effects in comparison with the textbook case of free (plane wave) electrons. For the latter, the exponential decay rate in the vacuum is minimal for electrons with the parallel component of momentum ${\bf k}_\parallel=0$, and the prefactor i…
A theory for longitudinal (T1) and transverse (T2) electron spin coherence times in zincblende semiconductor quantum wells is developed based on a non-perturbative nanostructure model solved in a fourteen-band restricted basis set. Distinctly different dependences of coherence times on mobility, quantization energy, a…
Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $γ$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of…
We have investigated the structural and optical properties of Ga-doped ZnO films grown on GaN templates by plasma-assisted molecular-beam epitaxy. The carrier concentration in Ga-doped ZnO films can be controlled from 1.33×1018/cm3 to 1.13×1020/cm3. Despite high Ga incorporation, the linewidth of (0002) ω-rocking curv…
We consider an equilibrium structure of a monolayer formed by weakly charged polyelectrolyte chains tethered to the oppositely charged interface. The interface is characterized by an immobile charge spatially distributed in a sublayer of finite thickness submerging tethered polyions. The Coulomb attraction of tethered…
The rate of thermal decomposition (190−231 °C) of ethanol on Pd/Al 2 O 3 to yield CH 4, CO, and H 2 has been studied in a tubular reactor at differential conversion and in a Berty reactor. Ethanal is a byproduct that is also present as an intermediate species formed in a dehydrogenation reaction. The presence of H 2 i…
The synthesis, crystal structure, and physical characterization of the coordination compounds [Ni(en) 2 ] 4 [Fe(CN) 5 NO] 2 [Fe(CN) 6 ]·5H 2 O ( 1 ), [Ni(en) 2 ][Fe(CN) 5 NO]·3H 2 O ( 2 ), [Mn(3-MeOsalen)(H 2 O)] 2 [Fe(CN) 5 NO] ( 3 ), and [Mn(5-Brsalen)] 2 [Fe(CN) 5 NO] ( 4 ) are presented. 1 crystallizes in the mono…
Perovskite-based monolithic reactors have been studied for methane catalytic combustion. Monoliths have been prepared by washcoating cordierite honeycomb substrates with lanthanum-stabilized γ-Al 2 O 3, on which LaMnO 3 is dispersed. Scanning electron microscopy analysis showed a homogeneous distribution of LaMnO 3 on…
Complexes K11Na1[As2W18(Mn(H2O))3O66]x27H2O (1) and Na12[As2W18(Co(H2O))3O66]x34H2O (2) have been characterized. 1 crystallizes in the orthorhombic space group Pnma, with a = 30.6484(4) A, b = 14.9946(2) A, and c = 19.17080(10) A (Z = 4), while 2 crystallizes in the monoclinic space group C2/c, with a = 14.124(2) A, b…
Given the diversity and complexity of technologies involved in the surface treatments and coatings sector, it is very difficult to find references in the existing literature that interlink most of them. The work that is presented here is aimed at filling that gap. In view of its length, it has been necessary to divide…
The synthesis, structure, and physical properties of the series of molecular magnets formulated as [ZII(bpy)3][ClO4][MIICrIII(ox)3] (ZII = Ru, Fe, Co, and Ni; MII = Mn, Fe, Co, Ni, Cu, and Zn; ox = oxalate dianion) are presented. All the compounds are isostructural to the [Ru(bpy)3][ClO4][MnCr(ox)3] member whose struc…
Foaming of thermoplastic polymers is a complex process. Here models are presented that address the viscoelastic character of the thermoplastic melt during the expansion phase of foam development. Each cell is described as consisting of a spherical gas bubble surrounded by a spherical shell of polymer containing dissol…
A novel porous chitosan/gelatin scaffold for tissue engineering was prepared via polyelectrolyte complex formation, freeze drying and post-crosslinking with glutaraldehyde. The porosity and mean pore diameters could be controlled within 30∼100 µm by varying the original water content and the freezing conditions. Dippi…
Bulk and thin film GexSe1-x alloys have been prepared with 0.1≤X≤0.5.The bulk materials were obtained by quenching from the melt. They have beenused as source materials to produce thin film samples using the thermalevaporation method (semi-closed space technique). The composition of theobtained films was checked again…
The crystal structure and the magnetic state of polycrystalline LaMn 1− x V x O 3 (0.1< x <0.9) compounds have been studied by x-ray and neutron diffraction methods, as well as by magnetization and ac susceptibility measurements. It is shown that substitution of vanadium for manganese ions leaves the orthorhombic crys…
The polymerization of racemic lactide with a racemic aluminum alkoxide catalyst is reported. Microstructural analysis of the polymer produced with 1H NMR spectroscopy revealed that an isotactic stereoblock poly(lactic acid) formed, where each enantiomerically pure block contained an average of 11 lactide monomer units…
Part I provided a detailed description of a model developed to predict the mechanical properties of yarns and cords from single-filament properties. The objective in Part II is to assess the accuracy of the model by comparing predicted results with experimental data. Multifilament PET yams were obtained from various m…
From the stem of CaLotropis procera, olean-12-en-28 oic acid-3-0-a-L-rhamnopyranosyl (J~2) ~-D-glucopyranosyl ( I ~2) !)-D-galactopyranoside 1 and 3-0{ ~D-glucopyranosyl (J ~2)-!)D-glucopyranosyl (J ~6)-~D-glucopyranosyl ( 1~3)-aL-arabinopyranoside) olean-12-en-28-0-~D-glucopyranosyl 2 have been isolated. Their struct…
Palladium and palladium-copper catalysts supported on silica and niobia were characterized by H2 chemisorption and H2-O2 titration. Systems over silica were also analyzed by transmission electron microscopy and EXAFS. The metallic dispersion decreased from 20% to 7% when the content of Pd was increased from 0.5wt.-% t…
Second-harmonic generation (SHG) was observed from thermally poled alkaline earth containing mixed alkali silicate glasses. Since no SHG could be observed in alkaline-earth oxide-free glasses, it was considered that alkaline-earth oxide played a significant role in the generation. The intensity of SHG increased with t…