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排序方式: 共有233条查询结果,搜索用时 46 毫秒
71.
72.
The metal complex stability constants of Th(IV) with desferrioxamine B (DFO) and three octadentate derivatives [N-(2,3-dihydroxy-4-carboxybenzoyl)desferrioxamine B (DFOCAMC), N-(1,2-dihydro-1-hydroxy-2-oxopyridin-6-yl)carbonyl)desferrioxamine B (DFO-1,2-HOPO) and N-(2,3-dihydroxy-4-(methylamido)benzoyl)desferrioxamine B (DFOMTA)] have been determined. The formation constant of the Pu(IV)/DFOMTA complex has also been determined, and the formation constants have been estimated for the other Pu(IV) complexes of octadentate DFO derivatives. The DFO derivatives form 1:1 complexes with Th(IV) in aqueous solution. The solution chemistry of the Th(IV) complexes has been studied by spectrophotometric, potentiometric and proton NMR titrations. The Th(IV) formation constants are as follows (log K(f) values and esd's): DFO, 26.6(1); DFOMTA, 38.55(5); DFOCAMC, 37.2(3); DFO-1,2-HOPO, 33.7(4). The Pu(IV)/DFOMTA formation constant, determined by competitive spectrophotometric titration is (log K(f) value) 41.7(2). The estimation of the other Pu(IV) formation constants are as follows (log K(f) values): DFOCAMC, 40.4; DFO-1,2-HOPO, 36.9. The selectivity of DFO and the three derivatives for actinide(IV) ions is discussed. 相似文献
73.
The adsorption and depletion of the anionic polymer poly(styrene sulfonate) (PSS) on fresh human red blood cells (RBC) were investigated by measuring RBC electrophoretic mobility as a function of polymer molecular mass (48-2610 kDa), ionic strength (15 and 150 mM NaCl) and polymer concentration (相似文献
74.
KM Clauwaert Van Bocxlaer JF HJ Major JA Claereboudt WE Lambert Van den Eeckhout EM Van Peteghem CH De Leenheer AP 《Rapid communications in mass spectrometry : RCM》1999,13(14):1540-1545
This paper describes the investigation of the potential of a quadrupole orthogonal acceleration time-of-flight mass spectrometer (Q-TOF) equipped with an atmospheric pressure ionisation interface for quantitative measurements of small molecules separated by reversed phase liquid chromatography. To this end, the detection limits and linear dynamic range in particular were studied in an LC/MS/MS experiment using 3,4-methylenedioxymethamphetamine standards and 3,4-methylenedioxyethylamphetamine for internal standardisation. In a second phase, the experiment was repeated with real biological extracts (whole blood, serum, and vitreous humour). A calibration for 3,4-methylenedioxymethamphetamine and its metabolite 3,4-methylenedioxyamphetamine was prepared in each of these matrices again using 3,4-methylenedioxyethylamphetamine as internal standard. The resulting quantitative data were compared with those obtained by liquid chromatography with fluorescence detection for the same extracts. The Q-TOF results revealed excellent sensitivity and a linear dynamic range of nearly four decades (2-10 000 pg on-column, r(2) = 0.9998, 1/x weighting). Furthermore, all the calibration curves prepared in biological material were superimposable, LC/MS/MS and LC-fluorescence, and the quantitative results for actual samples compared very favourably. It was concluded that the Q-TOF achieves a linear dynamic range for quantitative LC/MS/MS work exceeding that of fluorescence detection and at much better absolute sensitivity. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
75.
中低变质程度煤显微组分结构的13 C-NMR研究 总被引:4,自引:1,他引:4
利用13C-NMR核磁共振技术对中低变质程度煤显微组分(镜质组和惰质组)的分子结构进行了研究,计算了5种煤9个显微组分的13C-NMR结构参数,获得了样品的结构特征及变化规律。结果表明,惰质组结构中芳构化程度要高于镜质组;脂碳数量则少于镜质组,芳环上的烷烃侧链也没有镜质组长;随着煤变质程度的提高,煤分子中芳构化程度不断提高,但惰质组的芳香度随变质程度变化的规律明显不如镜质组;在中低变质阶段,对煤化进程起主导作用的的是芳构化作用而不是环缩合作用,但在惰质组中脂碳断裂形成芳环的现象不明显。惰质组中含氧官能团的总量要低于同等变质程度的镜质组。 相似文献
76.
W. Merz H. -J. Neu M. Kuck K. Winkler S. Gorbach und H. Muffler 《Fresenius' Journal of Analytical Chemistry》1986,325(5):449-460
Zusammenfassung Es wird ein Verfahren beschrieben, mit dessen Hilfe es möglich ist, Substanzen unter definierten Bedingungen bezüglich Temperatur, Sauerstoffangebot und Verweilzeit zu verbrennen und die entstehenden Brandgase analytisch zu erfassen. Die Verbrennungsapparatur wurde unter besonderer Berücksichtigung der Erfordernisse für die analytische Probenahme konzipiert. Das Verfahren erlaubt es, die unter definierten reproduzierbaren Verbrennungsbedingungen erzeugten Brandgase zu untersuchen und durch Variation der Randbedingungen ein Gesamtbild der bei einem realen Brand möglicherweise entstehenden Stoffe zu erhalten. In drei voneinander unabhängig arbeitenden Laboratorien wurden mit fünf Modellstoffen gut übereinstimmende Analysenergebnisse erhalten.
Offprint requests to: Verband der Chemischen Industrie e.V., Herrn Dr. Fink, Postfach 111943, D-6000 Frankfurt/M., Bundesrepublik Deutschland 相似文献
A process for the generation and analytical characterization of gaseous combustion products
Summary A process is described that allows substances to be burned under defined conditions, i.e. temperature, oxygen supply and residence time, and the fumes to be analyzed. Special allowance for sampling the fumes was made in designing the combustion apparatus. The method allows the fumes given off under defined and reproducible combustion conditions to be investigated. A complete picture of the substances that might be given off in the event of a real fire can then be obtained by varying the boundary conditions. The analytical results on five model substances in three independent laboratories agreed well with one another.
Offprint requests to: Verband der Chemischen Industrie e.V., Herrn Dr. Fink, Postfach 111943, D-6000 Frankfurt/M., Bundesrepublik Deutschland 相似文献
77.
Preparation of U[N(EPPh2)2]3 (E = S or Se) by treating U[N(SiMe3)2]3 with three equivalents of NH(EPPh2)2 is described together with presentation of a hitherto unreported molecular crystal structure containing An(III)-Se bonds (An = actinide). 相似文献
78.
P. Bringel H. Hübel H. Amro M. Axiotis D. Bazzacco S. Bhattacharya R. Bhowmik J. Domscheit G.B. Hagemann D.R. Jensen Th. Kröll S. Lunardi D.R. Napoli A. Neußer S.C. Pancholi C.M. Petrache G. Schönwaßer A.K. Singh C. Ur 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):155-158
High-spin states in 161Lu and 162Lu have been investigated using the GASP γ-ray spectrometer array. Excited states in these nuclei have been populated through
the 100Mo(65Cu, xn) reaction at a beam energy of 260 MeV. Four presumably triaxial superdeformed bands, three in 162Lu and one in 161Lu, have been observed. This is the first evidence for triaxial superdeformation in the two isotopes.
Received: 18 October 2002 / Accepted: 21 November 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: bringel@iskp.uni-bonn.de
RID="b"
ID="b"Present address: Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520, USA.
RID="c"
ID="c"Present address: Physik Department, Technische Universit?t München, James Franck Str., D-85748 Garching, Germany.
Communicated by D. Schwalm 相似文献
79.
80.
H. Abele H. J. Hauser A. Körber W. Leitner R. Neu H. Plappert T. Rohwer G. Staudt M. Straßer S. Weite M. Walz P. D. Eversheim F. Hinterberger 《Zeitschrift für Physik A Hadrons and Nuclei》1987,326(4):373-381
Differential cross sections ofα-elastic scattering have been measured for the target nuclei11B,12C,13C,14N,15N, and16O atE=48.7 and 54.1 MeV and for the nuclei17O,18O, and20Ne atE=54.1 MeV. The experimental results were analysed in terms of the optical model using different complex potentials. Special emphasis is given to the application of the double-folding approach for the real part of the potential. The imaginary part is expressed in terms of Fourier-Bessel functions. Differential cross sections for theα-16O scattering over a wide energy range and for the elasticα-scattering for nuclei in the mass rangeA=11 up toA=24 atE=54.1 MeV are analysed by this method. A close correlation between the absorptive part of the potential and nuclear deformation is observed. 相似文献