Materials Literature
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Silica powder containing organized pores was prepared by a spray drying method. Silica and polystyrene latex (PSL) nanoparticles colloids were mixed and atomized to form micrometer-sized droplets. Nitrogen carrier gas was used to carry the resulting droplets into a vertical reactor that contained two heating zones: 20…
Oxygen non-stoichiometry, structural properties, and phase relations in Ca and Sr substituted LaMnO3 ± δ were studied by means of thermal analysis, X-ray diffraction, and iodometric titration. Hexagonal α-SrMnO3 − δ and LaMnO3 ± δ perovskite are only partly miscible. Room temperature metastable La1 − xSrxMnO3 ± δ soli…
The use of neutral surfactants to form a thermally stable ordered mesoporous ceria phase is reported. The judicious choice of cerium acetate as the inorganic framework precursor and the inorganic to surfactant ratio in the preparation mixture allowed the condensation of acetate derived inorganic polymer chains about t…
We investigate the structure and phase behavior of a two-component (binary) polymer brush in a solvent within self-consistent field theory as a function of the chains' stretching, the composition, and the incompatibility. Grafting the chains irreversibly prevents macrophase separation and the chains assemble into thre…
The dependence of electronic states on the length and diameter of CdSe quantum rods is investigated using semiempirical pseudopotential calculations. Energy levels cross as the aspect ratio increases due to their different dependence on length. The crossover between the highest occupied levels leads to a transition fr…
Several inorganic−organic hybrid complexes were synthesized from a synthetic clay (Sumecton SA) and cationic porphyrins (+4 charge). In the clay−porphyrin complexes, the λ max values of the Soret bands of the porphyrins were shifted to longer wavelengths compared to those in water. Two types of complexes were formed d…
The title compounds were synthesized and studied by solution and single-crystal absorption, luminescence, and excitation spectroscopy. The f-f luminescence is induced in the Tm(3+) and Yb(3+) complexes in solution by exciting into the (1)Pi-(1)Pi absorptions of the ligand in the UV. A single-configurational coordinate…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-State Structures of Metalloporphyrin NOx CompoundsGraeme R. A. Wyllie and W. Robert ScheidtView Author Information The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 Cite this: Chem. Rev. 2002, 102, 4, 1067–1090Publication…
We present Mn $3s$ x-ray photoelectron spectra of manganese oxides with the Mn formal valency from $2+$ to $4+.$ We found that the ${\mathrm{Sr}}^{2+}$ doping or cation deficiency in manganites do not change the Mn $3s$ splitting in manganites with the Mn formal valency from $3.0+$ to $3.3+.$ We suggest that doping ho…
Abstract The synthesis of organometallic polymers, namely Pt‐DOB ([ Pt ( PPh 3 ) 2 (CC p C 6 H 4 (2,5 OC 16 H 33 ) 2 C C )] n and Pt‐TRI ([ Pt ( PBu 3 ) 2 ( C C C 4 H 2 S C C C 4 H 2 S C C C 4 H 2 S C C )] n ) has been carried out. The platinum polyynes with a rigid rod structure have…
Abstract Thermal degradation mechanisms of the copolymers of styrene (St) with methacrylonitrile (MAN) and α‐methylstyrene (αMSt) were studied by pyrolysis gas chromatography (Py‐GC) and thermogravimetry (TG). Thermal degradation of vinyl polymers in flash pyrolysis proceeded mainly in the competition between depolyme…
Abstract A series of liquid crystalline copolyesters containing both horizontal and lateral rods in main chain were synthesized through solution polymerization of 2,5‐bis(4‐alkoxy benzoyloxy)hydroquinone, 4,4 ′‐dihydroxy‐α,ω‐diphenoxydecane and 4,4 ′‐dichloroformyl‐α,ω‐diphenoxydecane. These copolyesters were soluble…
The dielectric response has been studied in 10-μm-thick, single-crystal potassium tantalate films formed by crystal ion slicing. Scanning microwave microscopy shows that the implanted, pre-etched samples exhibit a bulk-like permittivity and low-loss tangent (0.0009) at 1.7 GHz. The separated free-standing films have s…
An improved oscillating drop method was developed to measure the surface tension and viscosity of a liquid without any external forces under microgravity conditions. The combination of a drop levitation system, a laser backlight system, and a line sensor enables the properties to be measured precisely. The surface ten…
Abstract Poly( L ‐lactide)–poly(ethylene glycol) (PLA–PEG) multiblock copolymers with predetermined short blocks ( M n ≤ 3000) were synthesized by polyesterification of PLA diols with PEG diacids in the presence of dicyclohexycarbodiimide and dimethylamide pyridine. The molecular structure and morphological features o…
An amorphous Ta(O,C)x layer was found to form at the TaC/Cu interface in the Si/TaC/Cu metallization system. The formation of the layer was induced by oxygen trapped in the as-deposited films, since on the basis of thermodynamic evaluation of the ternary Ta–C–O system, the dissociation of the TaC layer and the formati…
The noise properties at room temperature of multiwalled carbon nanotubes under forward bias, for frequencies between 10 Hz–10 kHz, have been investigated. The noise measurements were made for one individual multiwalled carbon nanotube (1 MW) and two crossing multiwalled carbon nanotubes (2 CMW). The excess noise found…
Domain switching behavior of 0.955Pb(Zn1/3Nb2/3)O3–0.045PbTiO3 ferroelectric single crystal has been investigated using the ultrasonic technique in addition to the polarization hysteresis measurements. The ultrasonic technique makes it possible to extend the coercive field measurement to frequencies as low as 10−5 Hz,…
Persistent ferromagnetic magnetization (M) as large as 0.6 μB per Mn site can be induced by irradiating visible laser pulses on a thin film of 1% Cr-doped Pr0.5Ca0.5MnO3. The enhancement of M upon the photoexcitation was also confirmed by the scanning superconducting quantum interference device microscope as an increa…
Shubnikov--de Haas (SdH) oscillations have been examined for organic conductors $\ensuremath{\lambda}\ensuremath{-}(\mathrm{BETS}{)}_{2}{\mathrm{Fe}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Cl}}_{4}$ $(x=0,$ 0.45, 0.78, and 1.0). In spite of the variety of the magnetic phases, no significant difference is found in…