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排序方式: 共有95条查询结果,搜索用时 15 毫秒
71.
Artem A. Babaryk Igor V. Zatovsky Vyacheslav N. Baumer Nikolay S. Slobodyanik Oleg V. Shishkin 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):i91-i93
Aliovalent KTP isomorphic compounds potassium chromium niobium oxide phosphate, KCr0.5Nb0.5OPO4, and potassium iron niobium oxide phosphate, KFe0.5Nb0.5OPO4, exhibit structures that differ from that of the non‐centrosymmetric KTiOPO4. There are two crystallographically independent octahedral sites, M1 and M2, statistically occupied by Nb and Cr (or Fe) atoms. The M1O6 and M2O6 octahedra are connected alternately to form a chain with a cis–trans arrangement. The Nb atoms prefer the M2 sites arranged in a cis‐like configuration. Each PO4 tetrahedon has the P atom on a twofold axis. Site‐splitting at the K‐atom position is observed in both compounds. In the isomorphous structures, one Nb atom lies on an inversion centre and the other on a twofold axis. Similarly with the pairs of Fe/Cr sites, one is on an inversion centre and the other on a twofold axis. 相似文献
72.
The nature of destruction of single crystals of lithium tetraborate Li2B4O7 under the action of a concentrated load is investigated. It is established that planes of easy crack propagation in Li2B4O7 single crystals are the (100), (010), (001), and {111} planes. It is found that crack propagation occurs in each case along the atomic layers that are linked by bridge oxygen atoms between main structural units (B4O9) and, therefore, are most weakly bound. 相似文献
73.
Oleg Sidletskiy Vyacheslav Baumer Iaroslav Gerasymov Boris Grinyov Konstantin Katrunov Nikolai Starzhinsky Oleg Tarasenko Vladimir Tarasov Sergiy Tkachenko Olesya Voloshina Olga Zelenskaya 《Radiation measurements》2010,45(3-6):365-368
Bulk Gd2Si2O7:Ce (GPS:Ce) single crystals obtained by Czochralski method demonstrate a high light output at γ-irradiation (3.8 times higher in comparison with Bi4Ge3O12 (BGO)), energy resolution 13% (137Cs, 662 KeV), fast decay time (41.7 ns), and good thermal stability of light output (up to 425 K). This combination of characteristics makes this scintillator very attractive for medical imaging and high-temperature applications. Light output at thermal neutron monitoring is evaluated as twice higher in comparison with Gd2SiO5:Ce (GSO). The observed rather high afterglow level (0.2% after 20 ms) and moderate energy resolution (13%) certifies a room for improvement of these parameters by further optimization of crystal quality. 相似文献
74.
Cherginets VL Baumer VN Galkin SS Glushkova LV Rebrova TP Shtitelman ZV 《Inorganic chemistry》2006,45(18):7367-7371
Alumina solubility in chloride-fluoride melts of KCl-NaCl-NaF mixtures with ratios of 0.425:0.425:0.15 (I), 0.38:0.38:0.24 (II), and 0.35:0.35:0.30 (III) (molar fractions) was investigated in the 973-1123 K temperature range using the isothermal saturation method. Al2O3 solubility in the ionic melts studied was shown to be on the order of 0.06 g kg(-1) for system I, 0.12 g kg(-1) for system II, and 0.14 g kg(-1) for system III at 1073 K. All the "Al2O3 + melt" systems were found to demonstrate negative deviations from the ideal solutions. The solubility of Al2O3 in all the melts increases with the temperature increase; however, the dependences of -log N(Al2O3) versus T(-1) were characterized by the slopes (2.6 +/- 0.4) x 10(3) K (I and II) and (2.4 +/- 0.6) x 10(3) K (III), which were considerably less than the slope predicted by the Shreder-Le Chatelier equation (approximately 5.8 x 10(3)). 相似文献
75.
76.
Sergiy M. Kovalenko Valentyn P. Chernykh Volodymyr M. Baumer Svitlana S. Kovalenko 《Monatshefte für Chemie / Chemical Monthly》2002,133(5):673-678
Summary. The condensation of salicylaldehyde, 1-methyl-4-piperidone, and methylamine has been studied as a model reaction. It was
found that at a molar ratio of salicylaldehyde: 1-methyl-4-piperidone = 2:1 and an excess of methylamine the previously unknown
heterocyclic compound 2-(3,6,13-trimethyl-1,2,3,4,4a,5,6,7-octahydro-7,12a-epiminopyrido[4,3-b][1,5]benzoxazocin-5-yl)-phenol was formed; its structure was elucidated by spectroscopic methods and X-ray analysis. A reaction
pathway for this new multi-component condensation is suggested and discussed.
Received August 20, 2001. Accepted (revised) November 15, 2001 相似文献
77.
S. V. Shishkina V. N. Baumer O. V. Shishkin A. L. Tatarets L. D. Patsenker 《Journal of Structural Chemistry》2005,46(1):154-158
X-ray investigation of 3-butoxy-4-(1,3,3-trimethyl-2,3-dihydro-1H-2-indolylidenemethyl)-3-cyclobutene-1,2-dione and its thio analog has been carried out. Replacement of the carbonyl oxygen atom by a sulfur atom causes electron density delocalization and equalization of the C-C bonds between the four-and five-membered rings. 相似文献
78.
R. E. Khoma V. O. Gel’mbol’dt A. A. Ennan V. N. Baumer I. M. Rakipov R. M. Dlubovskii 《Russian Journal of Inorganic Chemistry》2018,63(5):655-660
The reaction products formed in the SO2–L–H2O–O2 systems (L is n-propylamine, n-butylamine, tert-butylamine, n-heptylamine, n-octylamine, aniline) were isolated and identified as “onium” salts [n-C3H7NH3]2SO4, [n-C4H9NH3]2SO4, [t-C4H9NH3]2SO4, [n-C7H15NH3]3SO4(HSO4), [n-C8H17NH3]3SO4(HSO4), and [C6H5NH3]2SO4. The products were characterized by elemental analysis, IR and Raman spectroscopy, mass spectrometry, and thermogravimetry. 相似文献
79.
R. E. Khoma V. O. Gel’mbol’dt A. A. Ennan V. N. Baumer A. N. Puzan T. V. Koksharova A. V. Mazepa 《Russian Journal of Inorganic Chemistry》2017,62(6):736-745
Reaction products have been isolated from SO2–L–H2O–О2 systems (L = ethylenediamine, N,N,N′,N′-tetramethylethylenediamine, piperazine, and morpholine) as onium salts [H3NCH2CH2NH3]SO4, [(CH3)2NHCH2CH2NH(CH3)2]SO4, [(CH3)2NHCH2CH2NH(CH3)2]S2O6 ? H2O, [C4H8N2H4]SO3 ? H2O, [C4H8N2H4]S2O6, [C4H8N2H4]SO4 ? H2O, [O(C2H4)2NH2]2SO4 ? H2O. The prepared compounds have been characterized by X-ray diffraction analysis, X-ray powder diffraction, IR and mass spectroscopy. 相似文献
80.
N. N. Kolos V. D. Orlov B. V. Paponov O. V. Shishkin S. V. Baumer N. A. Kvashnitskaya 《Chemistry of Heterocyclic Compounds》1999,35(6):708-715
2,3-Diamino-5,7-diaryl-1,2,4-triazolo[1,5-a]pyrimidinium salts have been synthesized by the cyclocondensation of 3,4,5-triamino-1,2,4-triazole with 1,3-diaryl-2,3-propanes, and their structures and chemical properties have been studied.Kharkov State University, Kharkov 310077, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, 796–804 June, 1999. 相似文献