Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTDiels−Alder Trapping of Photochemically Generated Dienes with a Bismaleimide: A New Approach to Polyimide SynthesisMary Ann B. Meador, Michael A. Meador, Lesley L. Williams, and Daniel A. ScheimanView Author Information NASA Lewis R…
A novel Ti−V−W−sepiolite catalyst for the selective catalytic reduction (SCR) of NO x with NH 3 was characterized by surface area and pore size distribution measurements, SEM, EDX, XRD, and FT-IR and FT-LR spectroscopy: the catalyst consists of TiO 2 particles impregnated with vanadia and tungsta and dispersed among t…
Atomistic models of two different fluorinated polybenzoxazoles, 6F-PBO and 3F-PBO, were used to simulate the amorphous structures of these polymers. Molecular mechanics and molecular dynamics techniques were utilized to relax the independent structures from an initial high-energy system. The relaxed model structures s…
Reduction of N-phenyl-meso-tetraphenylporphyrin with tosylhydrazine gives air-stable N-phenyl-meso-tetraphenylphlorin.
In order to discuss the dielectric performance of DC GIS, the flashover characteristics of gas-insulated bus were studied under conical- and disk-type spacers. The test involves the investigation on effect of electrification for charge to be accumulated in spacers and the effect of metallic particles. As the result, i…
Porphocyanines are tetrapyrrolic macrocycles containing two dipyrromethene units linked together by two C N−C bridges. The syntheses of 2,3,7,8,14,15,19,20-octaethylporphocyanine, 5,17-diphenylporphocyanine, 2,3,7,8-tetraethyl-17-phenylporphocyanine, and other meso -aryl and β-alkyl, including a tetra-β-propionate, de…
The phenomenon of bistable hysteresis in magnetic resonance of conduction electrons in solids is discussed, particularly the case of gallium oxide β-Ga 2 O 3 . This memory effect is a consequence of the dynamic polarization of nuclei by the Overhauser effect and manifests itself by a hysteresis of the ESR line provide…
The polyborates Cs(2)M(2)B(10)O(17) (M = Na, K) have been prepared and their structures determined by single-crystal X-ray diffraction methods. They crystallize in the monoclinic space group C2/c (Z = 8) with unit-cell parameters a = 21.643(3) Å, b = 6.558(2) Å, c = 11.072(2) Å, beta = 105.43(1) degrees, V = 1514.8(6)…
New layered perovskite compounds, LiLnTiO4 (Ln=La and Eu), have been synthesized by an ion-exchange reaction from parent sodium compounds, NaLnTiO4. The crystal structures of LiLaTiO4 and LiEuTiO4 were determined by Rietveld analysis of the powder X-ray diffraction (XRD) patterns. The lithium ion-exchanged compounds r…
The paper presents the results of electric field and energy computation on insulating surfaces covered by water in the form ranging from small discrete droplets to large wet patches. The goal of this study was to understand the differences in the flash-over performance of outdoor insulators, in particular nonceramic i…
We report the results of a systematic orientation study on side-chain liquid crystalline polymers (SCLCPs) mechanically stretched in different mesophases. Two representative polyacrylate-based SCLCPs were used. The study demonstrates that the macroscopic orientation of the mesogens reflects a direct alignment of the l…
Scanning tunneling microscopy and optical spectroscopy of CdS nanoclusters and nanocluster self-assemblies were used to study the influence of capping ligands and cluster concentration on the aggregation process. Results are compared with TEM and X-ray diffraction data. Interaction and bonding between these self-conne…
The properties of the water contained in anionic clays have been investigated as a function of precalcination temperature and gallery height using quasi elastic neutron scattering (QENS). Two representative samples which differ in the geometry of the anions and the latter's hydration chemistry were used. The QENS resu…
Two mismatches, G.G and I.I, have been incorporated at the central position of 5'd-(GCCACXAGCTC).d(GAGCTXGTGGC) in order to carry out NMR and molecular dynamics studies. These duplexes constitute the sequence 29-39 of the K-ras gene coding for the glycine 12, a hot spot for mutation. The NMR spectra show that the dupl…
The structural elucidation of seven related oxypregnane-oligoglycosides stephanosides K (1), L (2), M (3), N (4), O (5), P (6), and Q (7) from the fresh stem of Stephanotis lutchuensis var. japonica (Asclepiadaceae) was achieved through on a detailed study of their high-field 1H- and 13C-NMR spectra. The results show…
The strengths of the $^{5}$${\mathit{D}}_{0}$${\mathrm{\ensuremath{-}}}^{7}$${\mathit{F}}_{\mathit{J}}$ (J=0,2,4) optical transitions of the ${\mathrm{Sm}}^{2+}$ ion in solids, which are due to the forced electric dipole transition, are analyzed by taking into account not only the Judd-Ofelt mechanism but also the exc…
Article Preparation of Dissolving Pulp from Sugar Cane Bagasse, and its Acetylation Under Homogeneous Solution Condition was published on January 1, 1996 in the journal Holzforschung (volume 50, issue 3).
New determinations of quantitative forward rate constants for reactions of titanium monomer cation with C 2 H 6, C 3 H 8, H 2 O, NH 3, and O 2 are accomplished using a high-pressure (multicollision) flow tube reactor. These experiments were prompted by our observation of conflicting reports in the literature. The reac…
Thermograms of fine, medium and coarse fibres prepared by cutting, milling and freezegrinding at 5°, 20° and 50°C/ min heating rates were compared. Scanning electron microscopy revealed that fibre ends prepared by the three methods were distinctly different from each other and, in addition, the mean length of the fibr…
The Fresnel diffraction of periodic objects at rational fractions of the Talbot distance is described in terms of the Wigner distribution function (WDF). The analysis provides a heuristic model for understanding the formation of the diffraction patterns as well as for evaluating the complex amplitude at any fractional…