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11.
Tamer Shoeib Junfang Zhao Houssain EI Aribi Alan C. Hopkinson K. W. Michael Siu 《Journal of the American Society for Mass Spectrometry》2013,24(1):38-48
The fragmentations of [AA + M]+ complexes, where AA = Phe, Tyr, Trp, or His, and M is a monovalent metal (Li, Na, or Ag), have been exhaustively studied through collision-induced dissociation (CID) and through deuterium labeling. Dissociations of the Li- and Ag-containing complexes gave a large number of fragment ions; by contrast, the sodium/amino acid complexes have lower binding energies, and dissociation resulted in much simpler spectra, with loss of the entire ligand dominating. Unambiguous assignments of these fragment ions were made and formation mechanisms are proposed. Of particular interest are fragmentations in which the charge was retained on the organic fragment and the metal was lost, either as a metal hydride (AgH) or hydroxide (LiOH) or as the silver atom (Ag?). Caption for Graphical Abstract
CID products of Li+, Na+, and Ag+ complexes of Phe, Tyr, Trp, and His are reported and mechanisms by which they are formed are proposed. 相似文献
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Irina Klimova Tiit Kaljuvee Valdek Mikli Andres Trikkel 《Journal of Thermal Analysis and Calorimetry》2013,111(1):253-258
Urea is one of the main nitrogen fertilizers used in agriculture. But being well soluble in water, hardly 50% of its nitrogen is assimilated by plants. One possibility to eliminate this disadvantage is to use coating agents for modification of urea to obtain a controlled-realized fertilizer. The aim of this research was to study the influence of different lime-containing additives on the thermal behavior and decomposition kinetics of urea in oxidizing atmosphere. Commercial fertilizer-grade urea (46.4% N) and analytical-grade CaO, MgO, CaCO3, MgCO3 were used in the experiments. In addition, one Estonian limestone and one dolomite sample were used as additive or coating material. The experiments with a Setaram Setsys 1750 thermoanalyzer coupled to a Nicolet 380 FTIR Spectrometer by a heated transfer line were carried out under non-isothermal conditions up to 900 °C at the heating rate of 5 °C min?1 and to calculate kinetic parameters, additionally, at 1, 2, and 10 °C min?1 in the atmosphere containing 80% of Ar and 20% of O2. The differential isoconversional method of Friedman was used to calculate the kinetic parameters. The results obtained indicate that thermooxidative decomposition of urea as well as the blends of urea with lime-containing materials and urea prills coated with limestone or dolomite powder follows a complex reaction mechanism. 相似文献
13.
Physicochemical and adsorption properties of hypercross‐linked polystyrene with ultimate cross‐linking density
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Maria P. Tsyurupa Zinaida K. Blinnikova Yuri A. Borisov Mikhail M. Ilyin Tamara P. Klimova Kiril V. Mitsen Vadim A. Davankov 《Journal of separation science》2014,37(7):803-810
The paper describes unexpected properties of hypercross‐linked polystyrenes with ultimate cross‐linking degrees of 300, 400, and 500%, where three, four, or five methylene links, respectively, could bind each polystyrene phenyl ring to its spacious neighbors. The polymers exhibit a strong electron spin resonance signal, unusual spectra in IR, UV, and visible ranges, and they are not typical dielectrics. The nonfunctionalized hypercross‐linked polymers absorb significant amounts of inorganic acids, salts, and bases due to interactions of protons or other cations with electron‐donating fragments of the aromatic network with the high extent of mutual connectivity and also due to dispersion interactions of anions with the polymer matrix. 相似文献
14.
Klimova A. V. Mikhailovskaya Z. A. Buyanova E. S. Petrova S. A. 《Russian Journal of Electrochemistry》2021,57(8):825-832
Russian Journal of Electrochemistry - The possibility of synthesizing oxygen-ion conductors based on bismuth molybdate with antimony and tin substituted to the molybdenum sublattice is studied and... 相似文献
15.
Yu. M. Gufan A. V. Pavlenko L. A. Reznichenko K. P. Andryushin O. A. Bunina Yu. D. Zavorotnev I. N. Zakharchenko G. M. Konstantinov S. P. Kubrin Yu. A. Kuprina I. A. Osipenko A. V. Pashchenko O. N. Razumovskaya E. N. Klimova D. A. Sarychev S. A. Simonenko 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(8):1121-1126
High-density impurity-free AFe2/3W1/3O3 (A = Ba(BWF), Sr(SWF), Pb(PWF)) ceramics with well-developed microstructures were synthesized. Their structures and dielectric properties were investigated over wide temperature (10–973 K) and frequency (25 Hz-1 MHz) ranges. These materials are found to be almost transparent in the microwave range. They were characterized by weak magnetoelectric interactions; ?(BWT) ≈ 50 up to 400 K and ?(BWT) and ?(PWT) have second maxima between 400 and 600 K. All properties are easily reproduced, regardless of slight variations in synthesis conditions. 相似文献
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The UV and visible spectra of frozen naphthalene-anthracene, naphthalene-naphthacene, and anthracenenaphthacene solutions have been studied. The effects of component concentrations on the spectra have been determined.In conclusion the authors express thanks to Prof. E. V.Shpol'skii for his constant attention to and interest in the work. 相似文献
19.
E. I. Klimova E. A. Vazquez Lopez T. Klimova M. Martinez Garcia Ortega S. Hernandez L. Ruiz Ramirez 《Russian Journal of General Chemistry》2004,74(11):1757-1762
Ferrocenyltetrahydropyrimidin-2-ones were prepared by reactions of linear and cyclic ,-unsaturated ketones of the ferrocene series with urea in i-PrOH in the presence of t-BuOK. The structures of the compounds prepared were studied by 1H and 13C NMR and IR spectroscopy, and also by single crystal X-ray diffraction.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1887–1893.Original Russian Text Copyright © 2004 by E. Klimova, Lorez, T. Klimova, Garcia, Hernandez, Ramirez.This revised version was published online in April 2005 with a corrected cover date. 相似文献
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