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71.
Summary Zinc may be determined polarographically in acetate buffered solutions of PH 4 to 5.6.
Zusammenfassung Die polarographische Bestimmung von Zink ist möglich in mit Acetat gepufferten Lösungen vom PH 4 bis 5,6.
Résumé On peut doser le zinc par polarographie dans des solutions de pH 4 à 5,6 tamponnées à l'acétate.相似文献
72.
Gagandeep Singh Naman Gupta Vivek Gupta Mohan Paul Singh Ishar 《Tetrahedron letters》2017,58(25):2456-2459
Reductive ring opening of isoxazolidine moiety of chromano–piperidine-fused isoxazolidines (3a–c) with HCOONH4 and 10% Pd/C in a mixture of solvents (THF/MeOH) at ambient temperature, affords novel 2-(methylamino)-4-oxo-N-phenyl-N-propyl-4H-chromene-3-carboxamide (4), which is apparently derived from reductive NO bond cleavage followed by tandem intramolecular rearrangements. Plausible mechanistic rationale for the formation of compound 4 is proffered. 相似文献
73.
In this study, it is demonstrated that silver nanoparticles can be transferred from formamide to chloroform using oleic acid as a phase transfer agent with a transfer efficiency of 90–95%. The silver nanoparticles are initially formed as an organosol by the reduction of silver ions with formamide. On aging the complex, the particles self-assemble to form an ordered close-packed two-dimensional array of silver nanocrystals when dissolved in CHCl3. The size distribution of the colloidal silver particles after transfer in different solvents remains almost the same. On the basis of IR spectroscopy, we discuss the adsorption of oleic acid over the silver particles. 相似文献
74.
75.
Volume changes associated with point defects in space charge layers can produce strains that substantially alter thermodynamic equilibrium near surfaces in ionic solids. For example, near-surface compressive stresses exceeding -10 GPa are predicted for ceria. The magnitude of this effect is consistent with anomalous lattice parameter increases that occur in ceria nanoparticles. These stresses should significantly alter defect concentrations and key transport properties in a wide range of materials (e.g., ceria electrolytes in fuel cells). 相似文献
76.
Abstract
The crystal structure of the title compound, 3β-hydroxy-16α-methylpregn-5-en-20-one, C22H34O2, was determined by direct methods using single crystal X-ray diffraction data. The compound crystallizes in the triclinic space group P1 with unit-cell parameters: a = 6.235(1) ?, b = 6.282(1) ?, c = 12.877(3) ?, α = 96.672(4)°, β = 98.746(4)°, γ = 106.838(4)°, Z = 1. The structure was refined by full-matrix least-squares to R = 0.0573 for 2,196 observed reflections. Rings A and C of the compound are in chair conformation whereas ring B is in half-chair conformation. Ring D is in envelope conformation. The A/B ring junction is quasi-trans, while ring systems B/C and C/D are trans fused about the C8–C9 and C13–C14 bonds, respectively. The steroid nucleus has a small twist, as shown by the C19–C10···C13–C18 pseudo-torsion angle of 8.0°. Molecules are connected via C–H···O hydrogen bonds to form straight chains along the c-axis of the unit cell. The straight chains are packed together to form layers. 相似文献77.
78.
79.
G. Kavitha S. R. C. Vivek A. Govindaraj Chandrabhas Narayana 《Journal of Chemical Sciences》2003,115(5-6):689-694
The paper discusses the design of a low cost Raman spectrometer. Single-walled nanotubes (SWNT) have been studied to demonstrate
the reach of such a system. We observe both the radial-breathing mode (RBM) and the tangential mode from the SWNT. The tube
diameters of the SWNT used in these experiments have been determined using RBM to be predominantly 1.4 and 1.6 nm. These are
consistent with the TEM images taken of the same sample. The new method of producing SWNT using Ni-Y catalyst in electric-arc
discharge method produces nanotubes with very small dispersion in diameter and high yields. The chirality of the SWNT can
be deduced from their radial breathing modes, and it suggests that they are metallic in nature.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献
80.