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11.
Ding F Kopach ME Sabat M Harman WD 《Journal of the American Chemical Society》2002,124(44):13080-13087
Electrophiles such as dimethoxymethane and 3-penten-2-one react with the complex [Os(NH(3))(5)(eta(2)-benzene)](2+) in the presence of triflic acid to form metastable benzenium intermediates. These benzenium intermediates further react with carbon nucleophiles including silyl ketene acetals, (silyloxy)alkenes, and phenyllithium in an overall tandem 1,4-addition sequence. The metal fragment controls the relative stereo- and regiochemistry for both electrophilic and nucleophilic addition steps. Upon oxidative demetalation with silver triflate, cis-1,4 cyclohexadienes are formed in yields ranging from 16 to 82%. This methodology can also be used to dearomatize toluene and ortho- and meta-xylene with unexpectedly high regio- and stereocontrol. 相似文献
12.
Ya. I. Korenman S. Kopach Ya. Kalembkievich L. Filar B. Papchak 《Journal of Analytical Chemistry》2000,55(1):25-28
The extraction of chromium(VI) from aqueous saline solutions (NaNO3) using a trioctylamine solution in toluene was studied in order to determine chromium(VI) in soil samples by atomic absorption
spectrometry. It was found that the quantitative recovery of chromium(VI) was attained after extraction with the 0.1 M extractant
solution (pH 1.5) for 15 min followed by-back extraction with 4 M HNO3. Chromium(III) was not extracted under these conditions 相似文献
13.
A study has been made of how the condensation conditions and the state of the substrate surface affect the structure of CdTe films grown on mica in a quasiclosed volume. Monocrystalline CdTe films on mica grow under conditions close to equilibrium when the coefficient of vapor supersaturation =1.06. The existence of silver islets on the mica surface stimulates the growth of perfect films with a smooth surface under conditions not as close to equilibrium with =1.5.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 101–104, June, 1978. 相似文献
14.
A comparison was made of island deposits of gold on NaCl, produced by thermal vaporization (thermal Au/NaClid) and cathode sputtering (cathode Au/NaClid). In thermal Au/NaClid, two orientations of the gold microcrystals with respect to the NaCl (100) shear face were observed; multiply twinned particles were formed. In cathode Au/NaClid, only one orientation is present and the formation of complex particles is not observed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 46–50, November, 1971. 相似文献
15.
16.
G. V. Danilyan J. Klenke V. A. Krakhotin Yu. N. Kopach V. V. Novitsky V. S. Pavlov P. B. Shatalov 《Physics of Atomic Nuclei》2011,74(5):671-674
Study of the T-odd three-vector correlation in the emission of prompt neutrons from 235U fission by polarized cold neutrons has been continued at the facility MEPHISTO of the FRM II reactor (Technical University
of Munich). The sought correlation was not found within experimental error of 2.3 × 10−5. The upper limit for the asymmetry coefficient has been set to |D
n
| < 6 × 10−5 at 99% confidence level, whereas for ternary fission correlation coefficient D
α
= (170±20) × 10−5. This limit casts doubt on a model that explains the three-vector correlation in ternary fission by the Coriolis mechanism.
At the same time, five-vector correlation in the emission of prompt fission neutrons has been measured, which describes the
rotation of the fissioning nucleus at the moment it breaks (ROT effect). At the angle 22.5° to the fission axis, the correlation
coefficient was found to be (1.57 ± 0.20) × 10−4, while at the angle of 67.5° it is zero within the experimental uncertainty. The existence of ROT effect in the emission
of prompt fission neutrons can be explained by the anisotropy of neutron emission in the rest frame of the fragment (fission
fragments are aligned with respect to the axis of deformation of the fissioning nucleus), similar to the mechanism of ROT
effect in the emission of prompt γ-rays. 相似文献
17.
Yu. V. Pyatkov D. V. Kamanin Yu. N. Kopach A. A. Aleksandrov I. A. Aleksandrova N. A. Kondrat’ev E. A. Kuznetsova A. N. Tyukavkin V. E. Zhuchko 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(7):949-952
The model of collinear cluster tri-partition with light ion (Be-Ne) emission discovered in the 235U(nth, f) reaction is discussed. Masses, velocities, energies, and nuclear charges, specific ionization losses of reaction products
known from experiment allow us to assume that the process is two-stage, where at the first stage the system forms into two
magic clusters, and at the second stage a light ion is detached from the light cluster, forming a magic remainder. 相似文献
18.
Fedorov N. A. Tretyakova T. Yu. Bystritsky V. M. Kopach Yu. N. Ruskov I. N. Skoy V. R. Grozdanov D. N. Zamyatin N. I. Dongming W. Aliev F. A. Hramco K. Kumar A. Gandhi A. Dabylova S. Yurkov D. I. Barmakov Yu. N. 《Physics of Atomic Nuclei》2019,82(4):343-350
The results obtained by measuring the angular and energy distributions of gamma rays produced in reactions induced by the inelastic scattering of 14.1-MeV neutrons on 27Al nuclei are presented. The respective measurements were performed by the tagged-neutron method in a beam from the ING-27 compact neutron generator. The angular distributions were obtained for gamma rays emitted from the 844-keV 1/2+, 1015-keV 3/2+, 2212-keV 7/2+, and 3004-keV 9/2+ states of 27 Al nuclei.
相似文献19.
20.
G. V. Val’skii A. S. Vorob’ev A. M. Gagarskii I. S. Guseva F. Gönnenwein T. A. Zavarukhina Yu. N. Kopach D. O. Krinitsyn M. Mutterer G. A. Petrov V. I. Petrova V. E. Sokolov O. A. Shcherbakov 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(3):354-362
Conditions for formation of angular and energy distributions of light particles emitted in ternary fission of 233, 235U, 239Pu, and 245Cm nuclei induced by cold polarized neutrons have been studied in the course of investigating T-odd asymmetry in emission of these particles with respect to the plane formed by the fission axis and the polarization axis of the fissioning nucleus. The results obtained lead to the conclusion that in ternary fission charged particles are emitted by the fissioning nuclear system rotating around the polarization direction. 相似文献