Materials Literature
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A systematic investigation of the effects of stereochemistry and solid-state morphology on emission characteristics were performed using glass-forming pyrenyl and carbazolyl derivatives as neat films in PMMA and cholesteric liquid crystalline glass. At high dilution in tetrahydrofuran, pyrenyl derivatives were prone t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLinear Trimerization Reaction of Silylacetylene Promoted by GaCl3Yoshiyuki Kido and Masahiko YamaguchiView Author Information Faculty of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan Cite this: J. Org. Chem. 1998, 63, 23, 8086–8087Publication…
The x-ray crystal structures of trans-cinnamoyl-subtilisin, an acyl-enzyme covalent intermediate of the serine protease subtilisin Carlsberg, have been determined to 2.2-A resolution in anhydrous acetonitrile and in water. The cinnamoyl-subtilisin structures are virtually identical in the two solvents. In addition, th…
Thiaminase-I catalyzes the replacement of the thiazole moiety of thiamin with a wide variety of nucleophiles, such as pyridine, aniline, catechols, quinoline, and cysteine. The crystal structure of the enzyme from Bacillus thiaminolyticus was determined at 2.5 A resolution by multiple isomorphous replacement and refin…
We have synthesized and characterized via single-crystal X-ray diffraction methods iron(II), ruthenium(II), and osmium(II) carbonyl derivatives of (1-methylimidazole)(5,10,15,20-tetraphenylporphyrinate) [(5,10,15,20-tetraphenylporphyrinate = TPP)], Fe(TPP)(CO)(1-MeIm)·toluene, Ru(TPP)(CO)(1-MeIm)·chloroform, and Os(TP…
A method was developed to determine the initial peripheral contact angle of sessile drops on solid surfaces from the rate of drop evaporation by using the published precise data of Rowan et al. The constant drop contact radius throughout this stage of evaporation, the initial weight (or volume), the weight decrease by…
Two activated carbons were prepared from olive stones with different degrees of activation and oxidized with a (NH 4 ) 2 S 2 O 8 solution for variable periods of time to introduce different amounts of oxygen surface complexes. Samples so prepared were characterized to know their surface area, porosity, and surface che…
Gold and silver nanorods of diameter 40 and 90 nm and having a variety of aspect ratios (length/diameter) were prepared using the template synthesis approach. After template synthesis, the nanorods were freed from the template membrane and dispersed in either hexafluoro-2-propanol (HFIP) or CHCl 3 . The stability of t…
Pinning phenomena in an incommensurate two-chain model of friction are studied numerically. The pinning effect due to the breaking of analyticity exists in the present model. The pinning behavior is, however, quite different from that for the breaking of analyticity state of the Frenkel-Kontorova model. When the elast…
We predict an extreme sensitivity to the dissipative losses of the resonant interaction of bulk phonons with a 2D defect in a solid. We show that the total resonant reflection of the transverse phonon at the 2D defect, described earlier without an account for dissipation, occurs only in the limit of extremely weak dis…
CrN is observed to undergo a paramagnetic to antiferromagnetic transition accompanied by a shear distortion from cubic NaCl-type to orthorhombic structure. Our first-principle plane wave and ultrasoft pseudopotential calculations confirm that the distorted antiferromagnetic phase with spin configuration arranged in do…
We found anomalies in the temperature dependence of the dielectric and the magnetic susceptibiliy of NaV_2O_5 in the microwave and far infrared frequency ranges. The anomalies occur at the phase transition temperature T_c, at which the spin gap opens. The real parts of the dielectric constants epsilon_a and epsilon_c…
The photophysical properties of a series of ethynyl-bridged (porphinato)zinc(II) oligomers have been investigated over the femtosecond and picosecond time scales using ultrafast magic angle and polarized pump−probe spectroscopy. Bis[(2,2‘,-5,10,15,20-tetraphenylporphinato)zinc(II)]ethyne, bis[(5,5‘,-10,20-diphenylporp…
Cu 2 O is an efficient catalyst in the partial oxidation of propylene to acrolein, while propylene oxidation on CuO leads to complete combustion. The interaction of propylene at elevated temperature ( > 300 K) and elevated pressure (5 Torr) with cuprous and cupric oxide has been investigated with core level XPS, reson…
We examine the dependence of the deformation obtained by bending quasi-Fuchsian structures on the bending lamination. We show that when we consider bending quasi-Fuchsian structures on a closed surface, the conditions obtained by Epstein and Marden to relate weak convergence of arbitrary laminations to the convergence…
Photoacoustic absorption measurements at room temperature are reported for Se1−xTex alloys in both crystalline and amorphous states for 0<x⩽0.3. The optical energy gap thus measured shows two features: (a) the gap decreases linearly as x increases with a change of slope at x=0.1 for both crystalline and amorpho…
Recent research into black powder problems experienced by natural-gas transmission pipelines indicates steps that can be taken to control the material in gas pipelines, gathering systems, and storage facilities. Black powder (the common term for various forms of iron sulfide mixed with contaminants) is the least under…
This work investigates the charge-transfer spectra of and complexes formed in anisotropic (X = Cl, Br) crystals. Attention is paid to the variations of the charge-transfer transition energies induced by chemical pressure effects when substituting along the crystal series. A salient feature of this study is the weak se…
The local atomic and magnetic structure of a powder crystalline sample of MnO has been modelled for a wide range of temperatures (10-1100 K) by fitting neutron powder diffraction data using the reverse Monte Carlo technique (RMC). This method allows simultaneous and self-consistent fitting of Bragg and diffuse scatter…
Carbon nanotubes can flatten into collapsed tubes with bulbs along either edge. The strong anisotropy in the graphitic radiation damage threshold both explains the rapid destruction of face-on flattened nanotubes and can be exploited to selectively modify the structure of edge-on flattened nanotubes, thereby creating…