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91.
Marián Kucharík František Šimko Vladimír Danielik Miroslav Boča Roman Vasiljev 《Monatshefte für Chemie / Chemical Monthly》2007,138(12):1211-1215
Summary. The phase diagram of the system Na3AlF6–NaVO3 was determined by means of thermal analysis. The system is a simple binary eutectic one. The eutectic point was estimated
at x(NaVO3) = 0.975 and t
eut = 617°C. The XRD patterns of samples after thermal analysis revealed the presence of cryolite and NaVO3 only supporting the above assumption of a simple eutectic binary system. 相似文献
92.
Jaromir Dmytrzyk Andrzej Kotarba Hanna Grabowska Roman Klimkiewicz 《Research on Chemical Intermediates》2004,30(3):337-342
The influence of gas-phase methylation of phenol on the state of the Fe-Si-Cr-K oxide catalyst surface was investigated by thermodesorption of K atoms and ions. Changes in potassium desorption energies, as determined from Arrhenius-like plots, varied from 3.07 eV to 1.21 eV for the atoms and from 2.59 eV to 2.89 eV for ion desorption from the active and deactivated samples, respectively. The results were discussed in terms of transformation of the catalyst surface and formation of β-ferrite. 相似文献
93.
Lucjan Chmielarz Piotr Kustrowski Marek Michalik Barbara Dudek Magdalena Czajka Roman Dziembaj 《Reaction Kinetics and Catalysis Letters》2007,91(2):369-378
Natural phlogophite, pre-treated with acids and intercalated with alumina pillars, was used as catalytic support. Transition
metals (Fe, Cu) were deposited on the surface of the modified clay materials by an ion-exchange method. The obtained samples
were characterized with respect to structure (XRD), texture (BET), composition (EPMA) and chemical nature of the deposited
transition metals species (UV-vis-DRS). The phlogophite based materials have been found to be active and selective catalysts
of the DeNOx process. The Fe-containing samples were catalytically active at lower temperatures than the clays modified with
copper. A competitive ammonia oxidation by oxygen decreased the effectiveness of the DeNOx process in the high temperature
range. 相似文献
94.
The occurrence of a series of new constituents which can be considered as Diels-Alder adducts of methyl vinyl ketone and ocimene (→1–4), myrcene (→ 9 , 10 ) or β-far-nesene ( → 11 , 12 ), respectively, was reported. Furthermore, the structures of four isomeric cyclohexene derivatives could be established as adducts 21–24 of (E, Z)- and (E, E)-1,3,5-undecatrience and methyl vinyl ketone. Another series of constituents having the norbornane skeleton represents adducts 25–32 , and 33–40 of methyl cyclopentadiene and 1-octen-3-one or methyl vinyl ketone, respectively. In accordance with Alder's endo-rule the endo-isomers are preponderant in the natural as well as in the synthetic mixtures. Most of these constituents could also be identified in a lavender absolute as well as in a freshly prepared hexane extract of lavender flowers (Lavandula officinalis CHAIX ). 相似文献
95.
E. Roman M. Sánchez-Avedillo J. L. de Segovia 《Applied Physics A: Materials Science & Processing》1984,35(1):35-40
In the present work, results of the interaction of O2 with polycrystalline titanium using AES, and ELS techniques, are presented. Changes in the shapes of Ti(LMV) and Ti(LMM) transitions and in the Ti(LM)O(V)/Ti(LMV) and Ti(LMV) Ti(LMM) amplitude ratios as well as a shift of the 34 eV loss peak [Ti(3p level], are studied as function of the oxygen exposure.At O2 pressures equal or less than 10–6 Pa and exposure up to 2000 L(O2) (weak oxidation), the Ti(LM)O(V)/Ti(LMV) and Ti(LMV)/Ti(LMM) ratios show three clearly distinct regions: (i) up to 20L there is a chemisorbed phase with the Ti(LMV)/Ti(LMM) ratio remaining constant and a fast linear increase in the Ti(LM)O(V)/Ti(LMM) ratio. (ii) At exposures higher than 20L the oxidation begins being characterized by a linear variation of the Ti(LM)O(V)/Ti(LMV) and Ti(LMV)/Ti(LMV) ratios, with positive and negative slopes, respectively. (iii) At 125L there is a change in both slopes but no stable value is achieved, despite the O(KLL)/Ti(LMM) ratio remains constant. Hence, it can be concluded that TiO is the final oxide obtained after that treatment, from features like the shape of the transitions and a maximum shift of 3eV of the Ti(3p) level, complemented with ESD experiments.On the other hand, experiments at pressures higher than 10–4Pa with or without the surfaces at 900K (strong oxidation) indicate that the most likely final oxide is TiO2.Work presented to the IXIVC-VICSS. Madrid (1983) 相似文献
96.
The weak interaction of neutral currents of the negative muon and a nucleus results inP-odd correlations in the one-photon 2s → 1s transition of light muonic atoms. If the standard electroweak model is used, the weak mixing of hyperfine components of the μ-atom 2s and 2p 1/2 orbits makes the main contribution to these correlations. A new mechanism of acting the hyperfine structure on theP-odd correlations is considered in the present work. The fact is that the hyperfine muon-nucleus interaction mixes the 2p 1/2 and 2p 3/2 orbits effectively in light muonic atoms whose nuclei have large quadrupole moments. As a result, two new sublevels arise for each of two valuesF ±=(I ± 1/2) of the total angular μ-atom momentum (I is the nuclear spin). The contributions of these sublevels to theP-odd correlations can be comparable with each other. The most strikes manifestation of the given effect occurs for berillium and boron, where the 2s and 2p 3/2 orbits may have close energies. Taking the above effect into account can lead to considerable modification of results against earlier calculations. In particular, theP-odd correlations can vanish and change sign. They can be additionally increased by a factor of several tens. 相似文献
97.
Roman Mazurkiewicz 《Monatshefte für Chemie / Chemical Monthly》1989,120(11):973-980
Summary N-Acylanthranilamides react with dibromotriphenylphosphorane in the presence of triethylamine as HBr captor to give 4-imino-4H-3,1-benzoxazines in good yields. If the reaction is carried out without acid acceptor, N-acetylanthranilamides yield 2-methyl-4-quinazolones, whereas N-benzoylanthranilamides give 2-phenyl-4-imino-4H-3,1-benzoxazines. It has also been found that 2-methyl-4-imino-4H-3,1-benzoxazines rearrange under the influence of HCl or HBr into the respective 2-methyl-4-quinazolones; 2-phenyl-4-imino-4H-3,1-benzoxazines, however, do not undergo such a rearrangement.
Synthese und Umlagerung von 4-Imino-4H-3,1-benzoxazinen
Zusammenfassung Die Umsetzung von N-Acyl-anthranilsäure-amiden mit Triphenyldibromphosphoran in Gegenwart von Triethylamin als HBr-Akzeptor führt mit guten Ausbeuten zu 4-Imino-4H-3,1-benzoxazinen. Wird die Reaktion ohne säurebindendes Mittel durchgeführt, dann entstehen aus N-Acetyl-anthranilsäure-amiden 2-Methylchinazolone-4, jedoch erhält man aus N-Benzoylanthranilsäure-amiden 2-Phenyl-4-imino-4H-3,1-benzoxazine. 2-Methyl-4-imino-4H-3,1-benzoxazine erleiden unter dem Einfluß von HBr oder HCl eine Umlagerung in entsprechende 2-Methylchinazolone-4, während 2-Phenyl-4-imino-4H-3,1-benzoxazine zu einer solchen Umlagerung nicht befähigt sind.相似文献
98.
N. N. Romanov O. V. Lazareva Yu. M. Volovenko 《Chemistry of Heterocyclic Compounds》1990,26(9):1065-1067
Derivatives of new condensed heterocyclic systems — pyrido- and quinolino[1,2:3,2]thiazolo[4,5-b]pyrazines — were synthesized by condensation of 2,3-dichloropyrazine with 2-mercaptopyridine and 2-mercaptoquinolines.See [1] for Communicaton 17.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1276–1278, September, 1990. 相似文献
99.
Roman Pogreb Oleg Popov Vlad Lirtsman Oleg Pyshkin Alexander Kazachkov Albina Musin Gene Whyman Binyamin Finkelshtein Yuri Shmukler Dan Davidov Alexander Gladkikh Edward Bormashenko 《先进技术聚合物》2006,17(1):20-25
The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene films and polypropylene‐rods, both doped with these complexes, were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)‐thenoyltrifluoroacetone‐1,10‐phenanthroline complex (1) and Eu(III)‐La(III)‐1,10‐phenanthroline complex (2). Absorption, excitation, emission spectra and lifetime of luminescence were studied. The impact of the polymer matrix on the emission spectra was investigated. Emission spectra of the films were studied at room and helium temperatures. Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) surface mapping showed that in the Eu(III)‐La(III) complex europium forms islands (clusters) with a dimension of 1 µm, whereas lanthanum was dispersed more uniformly in the polymer matrix. Dependence of emission intensity on the excitation was determined. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
100.
Roman Boča 《Theoretical chemistry accounts》1982,61(2):179-192
The perturbative configuration interaction using localized orbitals (the PCILO method) was extended in the way that current limitations to the two-centre bond approach were overcome. The localized molecular orbitals contain an arbitrary number of the basis set components; this follows from the a priori stated localized bonding model of a molecule. The extended PCILO method was formulated for the CNDO, INDO and NDDO Hamiltonian approximations. The configuration interaction was performed using the Rayleigh-Schrödinger many-body perturbation theory with the Møller-Plesset type of Hamiltonian partitioning, similar to that used in the so-called modified PCILO method. Applications to molecules with semi-localized and/or semi-delocalized bonds, as benzene or diborane, are presented. 相似文献