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581.
Pamela da Rocha PatrícioAparecida Barbosa Mageste Leandro Rodrigues de LemosRaquel Moreira Maduro de Carvalho Luis Henrique Mendes da SilvaMaria C. Hespanhol da Silva 《Fluid Phase Equilibria》2011,305(1):1-8
The phase diagrams of PEO1500 + sodium tartrate + water, PPO400 + sodium tartrate + water, PEO1500 + sodium succinate + water, PPO400 + sodium succinate + water, PEO1500 + sodium citrate + water, PPO400 + sodium citrate + water and PPO400 + sodium acetate + water aqueous two-phase systems were determined at (283.15, 298.15, and 313.15) K. Both equilibrium phases composition were analyzed by conductimetry and refractive index. In this paper, the influences of polymer hydrophobicity, salt nature and temperature on the phase diagram were analyzed. The phase separation processes was endothermic and the hydrophobic increase make easier the phase splitting, while the electrolyte capacity to induce phase separation follow the order: citrate > tartrate > succinate. The consistency of the tie-line data was ascertained by applying the Othmer-Tobias correlation. The experimental data were correlated with the NRTL model for the activity coefficient, with estimation of new interaction energy parameters. The results, analyzed in terms of root mean square deviations between experimental and calculated compositions, were considered satisfactory. 相似文献
582.
Laura M. Grubbs Shulin Ye Mariam Saifullah William E. AcreeJr. Pamela Twu Jared L. Anderson Gary A. Baker Michael H. Abraham 《Journal of solution chemistry》2011,40(12):2000-2022
Chromatographic retention data were measured for a wide range of organic solutes on 1-butyl-1-methylpyrrolidinium thiocyanate
([BMPyrr]+[SCN]−), hexyl(trimethyl)ammonium bis((trifluoromethyl)sulfonyl)imide ([HexM3Am]+[(Tf)2N]−), and 1-propyl-1-methylpiperidinium bis((trifluoromethyl)sulfonyl)imide ([PMPip]+[(Tf)2N]−) stationary phases at 323 and 353 K. The measured retention factors were combined with published infinite dilution activity
coefficient and gas-to-water partition coefficient data to yield gas-to-anhydrous ionic liquid (IL) partition coefficients
and water-to-anhydrous IL partition coefficients. Both sets of partition coefficients were analyzed using the Abraham model.
The derived Abraham model correlations describe the observed gas-to-IL and water-to-IL partition coefficient data to within
average standard deviations of 0.116 and 0.156 log10 units, respectively. 相似文献
583.
Rodríguez-Solla H Concellón C Blanco EG Sarmiento JI Díaz P Soengas RG 《The Journal of organic chemistry》2011,76(13):5461-5465
A chromium-mediated novel synthesis of carbohydrate-derived di- and trisubstituted (E)-α,β-unsaturated esters or amides from a range of dichloroesters or amides and a variety of sugar aldehydes is reported. The process took place with total stereoselectivity and in high yields. A mechanism based on a sequential chromium-promoted aldol-type reaction and a completely stereoselective β-elimination reaction is proposed to explain these results. 相似文献
584.
The performance (accuracy and robustness) of several clustering algorithms is studied for linearly dependent random variables in the presence of noise. It turns out that the error percentage quickly increases when the number of observations is less than the number of variables. This situation is common situation in experiments with DNA microarrays. Moreover, an a posteriori criterion to choose between two discordant clustering algorithm is presented. 相似文献
585.
Lijuan J. Wang Margaret L. Grapperhaus Barnett S. Pitzele Timothy J. Hagen Kam F. Fok Jeffrey A. Scholten Dale P. Spangler Mihaly V. Toth Gina M. Jerome William M. Moore Pamela T. Manning James A. Sikorski 《Heteroatom Chemistry》2002,13(1):77-83
The efficient syntheses of two new types of conformationally constrained S‐[2‐[(1‐iminoethyl)amino]ethyl]homocysteine derivatives, 1‐amino‐3‐[2[(1‐iminoethyl)amino]ethylthio]cyclobutane carboxylic Acid ( 5 ) and (4S)‐4‐[[2‐[(1‐Iminoethyl)amino]ethyl]thio]‐L‐proline ( 6 ), are reported. These molecules represent the first attempts to probe conformational constraint near the α‐amino acid moiety of known homocysteine‐based inhibitors of nitric oxide synthase. Targets 5 and 6 were evaluated as potential inhibitors of the three human isoforms of nitric oxide synthase. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:77–83, 2002; DOI 10.1002/hc.1109 相似文献
586.
Po-Hsiang Tang Pamela Berilyn So Zi-Jing Lin Chia-Chun Hsieh Lee-Jene Lai Chia-Her Lin 《中国化学会会志》2023,70(5):1108-1115
This paper mainly discusses the applicability of using soft x-ray tomography technology to examine the multidimensional structure of metal–organic frameworks, such as their core-shell and hollow framework, by visually observing their corresponding images in different energy bands by different excitation energies for different elements. The results show that the use of soft x-ray tomography (SXT) can effectively observe the distribution of metals in the structure, as well as observe the type of hollow pores the metal – organic framework (MOF) possesses. This pioneering evaluation of MOFs via SXT shows excellent performance in the structure identification of multidimensional metal–organic frameworks. 相似文献
587.
Christelle Miola‐Delaite Erwan Colomb Eric Pollet Thierry Hamaide 《Macromolecular Symposia》2000,153(1):275-286
588.
The metastable 1:1 Li/Na-stacked OP4-Li0.42Na0.37CoO2 phase is synthesized from a mixture of O3-LiCoO2 and P2-Na0.7CoO2 in a molar ratio of 42:58 (sealed gold tubes, 920 °C, 24 h, very fast quenching). 相似文献