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71.
Solvent extraction of alkali metal ions by batch and counter-current distribution methods was investigated with tetrathiocyanatodiamminechromate(III) and tetrathiocyanatodianilinechromate(III) as reagents and nitromethane and nitrobenzene as organic solvents. The distribution ratios of alkali metal ions in the various systems were measured. Cesium was readily extracted with the aniline compound and nitrobenzene. The separation of sodium from potassium in trace amounts was possible by the counter-current distribution method.  相似文献   
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Three novel diterpenes, phomactins K–M (13), were isolated from the cultures of an unidentified marine-derived fungus. The structures of 13 were elucidated from spectroscopic data (NMR, MS, IR), and the absolute configurations of 1, 2, and the relative configuration of 3 were determined by X-ray diffraction analysis.  相似文献   
74.
The structural determination of endohedral metallofullerenes has attracted special attention in disclosing the formation mechanism and developing new routes to bulk production. Recent advances in the theoretical and experimental studies are summarized with representative mono- and dimetallofullerenes such as M@C82 (M=Ca, Sc, Y, and La), Sc2@C84, and La2@C80. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 232–239, 1998  相似文献   
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Novel fluorescent substances, named panaefluorolines A-C (1-3), were isolated from the cultured mycobiont of a lichen, Amygdalaria panaeola. These structures were elucidated on the basis of spectroscopic data, especially 2D NMR.  相似文献   
77.
在Ru/Al2O3催化剂上进行了超临界条件下的固定床费托合成。研究了催化剂孔尺寸、α-C14烯共进料和反应温度对费托合成产物分布的影响  相似文献   
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The relative yield of the C-O bond breaking with respect to the C-C bond breaking in ethanol cation C2H5OH+ is maximized in intense laser fields (10(13)-10(15) Wcm2) by open-loop and closed-loop optimization procedures. In the open-loop optimization, a train of intense laser pulses are synthesized so that the temporal separation between the first and last pulses becomes 800 fs, and the number and width of the pulses within a train are systematically varied. When the duration of 800 fs is filled with laser fields by increasing the number of pulses or by stretching all pulses in a triple pulse train, the relative yield of the C-O bond breaking becomes significantly large. In the closed-loop optimization using a self-learning algorithm, the four dispersion coefficients or the phases of 128 frequency components of an intense laser pulse are adopted as optimized parameters. From these optimization experiments it is revealed that the yield ratio of the C-O bond breaking is maximized as far as the total duration of the intense laser field reaches as long as approximately 1 ps and that the intermittent disappearance of the laser field within a pulse does not affect the relative yields of the bond breaking pathways.  相似文献   
80.
Journal of Solid State Electrochemistry - The stress variations during polarization of iron thin film electrode in pH 8.4 borate buffer solution have been measured by a cantilever bending...  相似文献   
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