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901.
902.
V. A. D’yakonov A. A. Makarov E. Kh. Makarova L. M. Khalilov U. M. Dzhemilev 《Russian Journal of Organic Chemistry》2012,48(3):349-353
Cyclomagnesiation of nitrogen-containing 1,2-dienes with Grignard compounds in the presence of activated magnesium and Cp2TiCl2 as catalyst afforded 2,5-bis(aminoalkylidene)magnesacyclopentanes in high yield. 相似文献
903.
B. U. Edelmann 《Isotopes in environmental and health studies》2013,49(9):371-374
Zur Ausbildung eines intensiven Glowmaximums der Thermolumineszenz bei 200°C wurden eine Vielzahl von Kationen auf ihre Aktivatorwirkung gegenüber LiF untersucht. Als günstige Aktivatoren erwiesen sich bei der Herstellung des LiF mitgefällte Mg-, Ca- und Ti-Spuren. Die Eigenscaften der präparierten Phosphore werden mit den Analysenergebnissen verglichen und diskutiert. 相似文献
904.
M. D?ring U. -G. Mei?ner E. Oset A. Rusetsky 《The European Physical Journal A - Hadrons and Nuclei》2012,48(8):1-18
Phase shifts and resonance parameters can be obtained from finite-volume lattice spectra for interacting pairs of particles, moving with non-zero total momentum. We present a simple derivation of the method that is subsequently applied to obtain the ?Ц? and ??K phase shifts in the sectors with total isospin I = 0 and I = 1/2 , respectively. Considering different total momenta, one obtains extra data points for a given volume that allow for a very efficient extraction of the resonance parameters in the infinite-volume limit. Corrections due to the mixing of partial waves are provided. We expect that our results will help to optimize the strategies in lattice simulations, which aim at an accurate determination of the scattering and resonance properties. 相似文献
905.
U. D. Phalgune P. R. Rajamohanan B. G. Gaikwad R. J. Varma S. George 《Applied biochemistry and biotechnology》2013,169(7):2029-2037
The process of phenol biodegradation by the yeast Candida tropicalis NCIM 3556 in aqueous medium was studied by 1H, 13C, and DOSY NMR techniques. Samples at regular intervals were centrifuged to separate the cells, and 1H spectral data were collected at 400 MHz. Though a gradual decrease in the concentration of phenol was observed, after an incubation period of ~8 h, formation of any intermediate products could not be detected. Experiments carried out with uniformly 13C-labeled phenol also failed to detect formation of any carboxylic acid intermediates during degradation. The studies indicated that the phenol was completely degraded to carbon dioxide and water in approximately 20 h. Self-diffusion coefficient measurements showed that the lifetime of phenol in the bound form is too small to impart any change in its diffusion behavior and the intermediates formed are converted to carbon dioxide and water at a very fast rate. 相似文献
906.
U. S. Andropova N. A. Tebeneva A. N. Tarasenkov M. S. Parshin A. A. Askadskii O. A. Serenko A. M. Muzafarov 《Polymer Science Series B》2017,59(2):202-209
Amorphous polyaryleneetherketone tetrakis(phenyldiethoxysiloxy)hafnium or tetrakis(methyldiethoxysiloxy) hafnium are used as precursors of disperse phase of composites. One of the factors determining the morphology of filled polymer films and the size and shape of particles forming in polymer in situ is the activity of alkoxy groups of metal alkoxysiloxane precursor in hydrolysis and condensation reactions. When using tetrakis(phenyldiethoxysiloxy)hafnium instead of tetrakis(methyldiethoxysiloxy)hafnium, nanocomposites obtained via the sol-gel method are characterized by a uniform distribution of spherical particles of disperse phase. 相似文献
907.
K. Wallmann M. Kersten J. Gruber U. Förstner 《International journal of environmental analytical chemistry》2013,93(1-4):187-200
Abstract The binding forms of Co, Cd, Cu, Pb, and Zn in an anoxic, sulfide-bearing sediment were investigated by performing both thermodynamic equilibrium calculations and sequential extractions. Care was taken to maintain oxygen-free conditions during the whole experiment. The calculations suggested that trace metals were bound to sulfidic minerals. Sequential extraction results, however, showed increased importance of exchangeable and reducible fractions in the order Cu < Cd < Pb < Zn < Co. Thermodynamic equilibrium calculations of the chemical reactions during extraction showed that Cd, Co, Pb, and Zn sulfides are to a significant extent soluble in the acetate-exchangeable (step 1 + 2) and oxalate-reducible (step 3) fractions. Neglecting the dissolution of sulfide minerals would lead to a misinterpretation of the experimental results. 相似文献
908.
M. W. F. Nielen J. De Jong R. W. Frei U. A.Th. Brinkman 《International journal of environmental analytical chemistry》2013,93(1-3):37-48
Abstract A strongly basic anion-exchange resin is used for the trace enrichment and automated sample handling of phenol, with subsequent determination by reversed-phase liquid chromatography with fluorescence detection. Because of the presence of high concentrations of ionic compounds in the water samples tested, phenol is first trapped on a relatively long precolumn filled with a highly hydrophobic packing material; during this step, (in) organic anions which are not retained, are flushed to waste. In the next step, phenol is desorbed from this column at high pH and sorbed in a small zone (“peak compression”) on a short precolumn containing the anion exchanger. In the analysis of tap and river water samples, the detection limit was found to be 10ppt (1:1011). 相似文献
909.
Madlene U. Koller Katrina L. Peariso Tina S. Guion Shannon Studer Martinez Charles F. Beam 《合成通讯》2013,43(19):2963-2974
2-, 3-, or 4-Picolyllithium was prepared in excess lithium diiso-propylamide and condensed with several hydroxy-benzaldehydes and 4-hydroxy-acetophenone to afford substituted hydroxyphenyl-pyridyl-ethanols and α-hydroxyphenyl-α-methylpyridineethanols. In two instances. 3-picolyllithium condensed with aldehydes to presumably form the hydroxyphenyl-pyridyl-ethanol, which underwent linear dehydration to the substituted pyridyl-ethylenyl-phenol. 相似文献
910.