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101.
G. M. Nair G. R. Mahajan D. R. Prabhu 《Journal of Radioanalytical and Nuclear Chemistry》1995,191(2):323-330
The extraction behavior of U(VI) and Pu(IV) with dioctyloctanamide (DOOA), dioctylethylhexanamide (DOEHA) and diisobutylethylhexanamide (DIBEHA) was investigated from nitric acid medium. With DOOA, U(VI) extraction is higher than that for Pu(IV) upto 5M HNO3 and the trend is reversed at higher acid concentrations. Extraction yield of U(VI) is higher than that for Pu(IV) in the case of DOEHA and DIBEHA. DIBEHA extraction of Pu(IV) is found to be very small. The lower value of the distribution ratio for Pu(IV) with branched amides was attributed to steric reasons. The possibility of using these amides for separation of U(VI) and Pu(IV) without valency adjustment was explored. Both U(VI) and Pu(IV) are extracted as their disolvates by DOOA and DOEHA. 相似文献
102.
Katritzky AR Witek RM Rodriguez-Garcia V Mohapatra PP Rogers JW Cusido J Abdel-Fattah AA Steel PJ 《The Journal of organic chemistry》2005,70(20):7866-7881
[Chemical reaction: See text] Benzotriazole reagents for thioacylation (RCSBt), thiocarbamoylation (RR'NCSBt), aryl/alkoxythioacylation (ROCSBt), and aryl/alkylthiothioacylation (RSCSBt) are synthesized, and their utility is assessed by syntheses of representative heteroaryl thioureas 3a-g, thioamides 15a-s, thionoesters 16a-h, thiocarbamates 17a-e, dithiocarbamates 18a-d, thiocarbonates 19a-c, and dithiocarbonates 20a-c. 相似文献
103.
Two low level impurities in 3-[2-(2-benzoxazolyl)ethyl]-5-ethyl-6-methyl-2(1H)-pyridinone drug substance (L-696,229) have been isolated by a combination of preparative HPLC, solid-phase extraction and liquid-liquid extraction. They were identified as 3-[2-(2-benzoxazolyl)ethyl]-5-ethyl-6-(2-phenylethyl)-2(1H)-pyridinone (I) and 6,6'-(2-phenyl-1,3-propanediyl)bis[3-[2-(2-benzoxazolyl)ethyl]-5-ethyl-2(1H)-pyridinone] (II) by mass spectrometry and by their (13)C and (1)H-NMR spectra. 相似文献
104.
Simultaneous double-color high-power continuous wave (CW) Raman fiber laser at 1239 nm and 1484 nm is demonstrated which uses CW 8.4 W Yb-doped double-clad fiber laser at 1064 nm as a pump, 1 km phosphosilicate fiber, and cascaded cavities consisting of two pairs of fiber Bragg grating (FBG) mirrors. Maximum output powers are 0.65 W at 1239 nm and 0.97 W at 1484 nm with a 50%/50% output mirror reflectivity pair, and 0.37 W at 1239 nm and 1.06 W at 1484 nm with a 75.5%/50% pair. The output characteristics of this laser for different FBG mirror reflectivities are reported. 相似文献
105.
W. E. Wallace K. M. Flynn C. M. Guttman D. L. VanderHart V. M. Prabhu A. De Silva N. M. Felix C. K. Ober 《Rapid communications in mass spectrometry : RCM》2009,23(13):1957-1962
The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring quantitatively their molecular mass distribution with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. A mathematical method for polydisperse materials is described that creates a calibration curve to correct the ion signal intensities in the mass spectrum to give a more reliable molecular mass distribution. Correction is required due to various sample preparation and instrumental effects that may produce a systematic mass bias in the number of oligomers measured. This method employs gravimetric mixtures of analytes with different degrees of functionalization. One calix[4]resorcinarene was found to give accurate molecular mass distributions with little correction, while another, having a very similar molecular structure, was found to exhibit strong over‐counting of the oligomers having a high degree of functionalization. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
106.
Pankaj Bandhoria Vivek K. Gupta Musarat Amina Naresh K. Satti Prabhu Dutt Krishan A. Suri 《Journal of chemical crystallography》2006,36(2):153-159
6α,7α-epoxy-5α,17α,dihydroxy-1-oxo-22R-witha-2,24-dienolide (C28H38O6) was isolated from Withania somnifera leaves. The structure of the withanolide was established by spectral analysis and X-ray diffraction studies as withanone. The compound crystallizes in the orthorhombic space group P212121 with unit cell parameters: a = 9.191(10) Å, b = 12.858(6) Å, c = 21.400(16) Å, Z = 4. The crystal structure was solved by direct methods and refined to R = 0.0603 for 1742 observed reflections. There is positional disorder of the H atom in a hydroxy group (O5), resulting in two possible hydrogen-bond linkages. All the rings of the steroid skeleton are trans connected. Ring A exists in a half-chair conformation, ring B is intermediate between a half-chair and a sofa, ring C a distorted chair, and five-membered ring D is intermediate between a half-chair and an envelope. The δ-lactone ring E adopts a sofa conformation. The twist along the length of the steroid nucleus is negligible [C19–C10…C13–C18=1.8°]. Both the hydroxy groups are involved in hydrogen bonding. 相似文献
107.
We present measurements of the particle velocity distribution in the slow flow of granular material through vertical channels. The velocities of particles adjacent to the smooth, transparent front face of the channel were determined by video imaging and particle tracking. We find that the mean velocity changes sharply in shear layers near the side walls, but remains constant in a substantial core. The velocity distribution is non-Gaussian, is anisotropic, and follows a power law at large velocities. Remarkably, the distribution is identical in the shear layer and the core. We show evidence of spatially correlated motion, and propose a mechanism for the generation of fluctuational motion in the absence of shear. 相似文献
108.
Richard S. Glass William N. Setzer Usha Devi G. Prabhu George S. Wilson 《Tetrahedron letters》1982,23(23):2335-2338
Highly diastereoselective oxidations of -alcohol to the corresponding sulfoxides, the relative stereochemistries of these sulfoxides and that of an intermediary alkoxysulfonium salt determined by X-ray crystallographic analysis is reported. 相似文献
109.
The distribution of ladder variables is obtained for the class of processes with stationary independent increments for which they are almost surely positive. This result is used to derive some related distributions. It is proved that a Wiener-Hopf factorization completely analogous to the one for random walks holds if and only if the process is compound Poisson with zero drift. 相似文献
110.
Prabhu L. Bhatnagar 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1966,17(5):646-649
Zusammenfassung Für eine laminar zwischen zwei parallelen Wänden strömende viskoelastische Flüssigkeit mit Stoffgleichung nachNoll wird der Wärmeübergang zwischen den Wänden für konstante bzw. linear veränderliche Wandtemperatur berechnet. 相似文献