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121.
A.?Dev S.?Chakrabarti S.?Kar S.?ChaudhuriEmail author 《Journal of nanoparticle research》2005,7(2-3):195-201
Mg0.05Zn0.95O/SiO2 nanocomposite films in the molar ratio 25:75 consisting of Mg0.05Zn0.95O nanoparticles embedded in a dielectric matrix were prepared by sol–gel technique (spin coating). Optical transmittance, Raman effect and photoluminescence measurements of the composites indicated effective capping of the Mg0.05Zn0.95O nanoparticles (radii 1. 61–1.68 nm) in the host showing practically no variation of particle size with the post deposition annealing treatments. The blue shift of the band gap (4.29–4.23 eV) from that of bulk Mg0.05Zn0.95O indicated strong carrier confinement for samples annealed at T ≤ 873 K. Highly intense UV emission ( ∼ 4.14 eV) compared to that of defect related emission (2.59 eV) at room temperature was obtained by incorporating 5% Mg in ZnO.This revised version was published online in August 2005 with a corrected issue number. 相似文献
122.
A new general procedure for the functionalization of 4α-Me group in triterpenoids, reported earlier, has been utilized for the conversion of cyclolaudenol to 31-norcyclolaudenone a triterpene isolated from Musa sapientum. A convenient method for the cleavage of CC bond in enamines with RuO4 is reported. 相似文献
123.
Structures of two new diterpenoids, cembrene-A and mukulol are reported. Cembrene-A is one of the two most elementary tetraenes derivable from geranyl-geranyl pyrophosphate by C1 → C14 cyclization. Mukulol is also a cembrane derivative and is biogenetically closely related to cembrene-A. 相似文献
124.
Absolute stereochemistry of mukulol, a diterpene alcohol, is established by chemical correlation with cembrene-A and (+)-cis-piperitol. Synthesis of (+)-cis-piperitol and (?)-trans-piperitol from (+)-Δ2-carene is described. Δ2-Carene oxide on exposure to silica gel passes into cis Δ2-p-menthen-1,8-diol. 相似文献
125.
Sayan Dev Mukherjee 《Physics letters. A》1978,64(5):453-454
The channeling of 1.7 MeV protons along 〈100〉 axial direction, (100), (110) and (111) planar directions in magnesium oxide single crystals and axial to planar channeling transitions from 〈100〉 to (100), (110) and (210) have been studied experimentally. The experimental data and preliminary analysis of results are presented. 相似文献
126.
Isolation and structure elucidation of two long-chain aliphatic tetrols, now formulated as octadecan-1,2,3,4-tetrol and eicosan-1,2,3,4-tetrol, from gum-resin of Commiphora mukul, is described. There is evidence for the occurrence of nonadecan-1,2,3,4-tetrol, as well, in the resin. This is the first reported occurrence of such compounds in nature, though the closely related phytosphingosines (e.g. 2-amino-octadecan-1,3,4-triol) are well known. 相似文献
127.
In this paper solutions in series form for the stresses due to a nucleus of thermo-elastic strain in an infinite elastic solid in the presence of a spherical cavity and also in an elastic solid sphere have been found.
Nomenclature x, y, z Cartesian coordinates; - r, , spherical polar coordinates; - u x ,u y ,u z components of displacement in Cartesian coordinates; - u r ,u ,u components of displacement in spherical coordinates; - r , , , , r , components of stress in spherical coordinates; - E coefficient of elasticity in stress; - G coefficient of elasticity in shear; - coefficient of linear expansion; - Poisson's ration The following nomenclature has been used in this paper: 相似文献
Zusammenfassung Die thermischen Spannungen in einem festen Körper unendlicher Ausdehnung, welcher einen sphärischen Hohlraum enthält, sind bei einer Temperatur von 0°C in Gegenwart eines erhitzten Elementes, das sich in endlichem Abstand vom Hohlraum befindet, hergeleitet worden, wobei zahlenmässige Angaben für die Spannungen und Verschiebungen an der Oberfläche des Hohlraums gemacht werden können. Die Ergebnisse sind mit den entsprechenden, für den zweidimensionalen Fall gültigen Zahlenwerten verglichen worden. Ferner was es möglich, auch für das Problem einer festen Kugel von der Temperatur 0°C und einem erhitzten Kern in ihrem Innern eine Lösung zu finden.
Nomenclature x, y, z Cartesian coordinates; - r, , spherical polar coordinates; - u x ,u y ,u z components of displacement in Cartesian coordinates; - u r ,u ,u components of displacement in spherical coordinates; - r , , , , r , components of stress in spherical coordinates; - E coefficient of elasticity in stress; - G coefficient of elasticity in shear; - coefficient of linear expansion; - Poisson's ration The following nomenclature has been used in this paper: 相似文献
128.
Isolation and structure elucidation of a novel monoterpene phenol, bakuchiol, from the seeds of Psoralea corylifolia Linn, is described. 相似文献
129.
Ashok G. Bajaj Sukh Dev Bruce Tagle Joshua Telser Jon Clardy 《Tetrahedron letters》1980,21(4):325-326
Allohimachalol, an unusual rearranged sesquiterpene from the essential oil of Loud., is shown to have structure 3. 相似文献
130.
Stereospecific conversion of 9,19-cyclo-4,4,14α-trimethyl-3β-acetoxy-5α,9β-pregnan-20-one, readily accessible from cycloartenol/cyclolaudenol, into three closely related Buxus alkaloids—buxandonine, cyclo-protobuxine-F and cycloprotobuxine-A—is described. 相似文献