Materials Literature
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Titanium dioxide (TiO2) is widely used for applications in heterogeneous photocatalysis. We prepared nanocrystalline powders of the anatase as well as the rutile modification by high-energy ball milling of the coarse grained source materials for up to 4 h. The resulting average grain size was about 20 nm. The morpholo…
The advantages of bimetallic nanoparticles as C-C coupling catalysts are discussed, and a simple, bottom-up synthesis method of core-shell Ni-Pd clusters is presented. This method combines electrochemical and 'wet chemical' techniques, and enables the preparation of highly monodispersed structured bimetallic nanoclust…
Photoluminescence (PL) properties of B and P codoped and compensated Si nanocrystals were studied. The compensation of carriers in nanocrystals was confirmed by the annihilation of confined-carrier optical absorption in the infrared region. In the PL spectra obtained under the resonant excitation condition, the codope…
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The crystallization behaviors of the poly(ethylene glycol)-poly(epsilon-caprolactone) diblock copolymer with the PEG weight fraction of 0.50 (PEG(50)-PCL(50)) was studied by DSC, WAXD, SAXS, and FTIR. A superposed melting point at 58.5 degrees C and a superposed crystallization temperature at 35.4 degrees C were obtai…
Thermoreversible gelation of diblock copolymers of a helical polypeptide, poly(γ-benzyl-L-glutamate) and random-coil polymers such as polyferrocenylsilanes in dilute solution has been discovered (see picture). A new mechanism for self-assembly of block copolymers of helical polypeptides is proposed.
We report on the monotonic Raman frequency shift and intensity variation when a laser spot moves along the same single-walled carbon nanotube (SWNT) for both the radial-breathing mode (RBM) and the G-band. Our substrates are Si wafers coated with thermal oxide, and trenches with widths of 1-80 mum are etched in the Si…
The synthesis of a 2D hexagonal highly ordered periodic mesoporous 1,4-divinylbenzene-bridged organosilica (PMO) with crystal-like pore walls is reported. Both functionalities are realized by utilization of one single precursor (1,4-bis-(( E )-2-(triethoxysilyl)vinyl)benzene (BTEVB) which was synthesized via Pd-cataly…
Abstract Summary: The reaction between octaaminophenyl polyhedral oligomeric silsesquioxane (OAPS) and 2,2′‐(1,3‐phenylene)‐bis(4,5‐dihydro‐oxazoles) (PBO) over different temperature ranges was confirmed by FT‐IR spectroscopy. The OAPS was used to modify benzoxazine (BZ) in the presence of PBO. The novel polybenzoxazi…
Size-controllable monodisperse europium(II) sulfide (EuS) nanocrystals were synthesized by thermal decomposition of single molecular precursors [Eu(phen)(ddtc)3] or [Eu(bpy)(ddtc)3]. These crystals range from nano-polygons to nanocubes, and have uniform sizes from 2.6 to 20 nm (see Figure). They show size-dependent op…
We present a comprehensive study of ferromagnetism and magnetotransport in Mn-doped germanium, grown with molecular-beam epitaxy. Ferromagnetism in ${\mathrm{Mn}}_{x}{\mathrm{Ge}}_{1\ensuremath{-}x}$ $(0<x<0.09)$ is characterized by two different ordering temperatures ${T}_{C}$ and ${T}_{C}^{*}$ with ${T}_{C}⪡{T…
Discontinuous magnetic multilayers [CoFe/Al2O3] are studied by use of magnetometry, susceptometry and numeric simulations. Soft ferromagnetic Co80Fe20 nanoparticles are embedded in a diamagnetic insulating a-Al2O3 matrix and can be considered as homogeneously magnetized superspins exhibiting randomness of size (viz. m…
Extensive density-functional calculations are performed to understand atomic chemisorption on the TiC(111) and TiN(111) surfaces, in particular the calculated pyramid-shaped trends in the adsorption energies for second- and third-period adatoms. Our previously proposed concerted-coupling model for chemisorption on TiC…
The dependence of the critical current density Jc on hydrostatic pressure to 0.6 GPa is determined for a single 25-degree [001]-tilt grain boundary in a bicrystalline ring of nearly optimally doped melt-textured YBa2Cu3Ox. Jc is found to increase rapidly under pressure at +20 %/GPa. A new diagnostic method is introduc…
We present a simple, generally applicable procedure for the assembly of nanoparticles on carbon nanotubes in aqueous solution. The method makes use of polyelectrolytes for wrapping carbon nanotubes and providing them with adsorption sites for electrostatically driven nanoparticle deposition. The method is exemplified…
A self-organized film of boron nitride nanotube–polyaniline (BNNT–PANI) composite is fabricated by using a simple solution method. The BNNTs are fully coated with PANI as a result of strong interactions between these components (see picture). Mechanically tough, BNNTs may have potential as stabilizing additives to PAN…
The dimeric, pentacopper(II)-substituted tungstosilicate [Cu(5)(OH)(4)(H(2)O)(2)(A-alpha-SiW(9)O(33))(2)](10)(-) (1) has been characterized by single-crystal X-ray diffraction, elemental analysis, IR, electrochemistry, magnetic measurements, electron paramagnetic resonance (EPR), and mass spectrometry (MS). Magnetizat…
CdTe nanocrystals (NCs) capped with thioglycolic acid (TGA) were synthesized via a microwave-assisted method. The chemiluminescence (CL) of CdTe NCs induced by directly chemical oxidation and its size-depended and surfactant-sensitized effect in aqueous solution were then investigated. It was found that oxidants, espe…
Angle-dispersive x-ray diffraction (ADXRD) and x-ray absorption near edge structure (XANES) measurements have been performed in the AWO4 tungstates CaWO4 and SrWO4 under high pressure up to approximately 20 GPa. Similar phase transitions and phase transition pressures have been observed for both tungstates using the t…
A simple mechanical spring-block model is introduced for studying magnetization phenomena and in particular the Barkhausen noise. The model captures and reproduces the accepted microscopic picture of domain wall movement and pinning. Computer simulations suggest that the model is able to reproduce the main characteris…