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Measurements are performed of the density of photoneutron fluxes from cylindrical targets of2H2O (diameter 64 and height 86 mm), Be (outer diameter 70, inner diameter 40, height 100mm), and238U (diameter 44.5 mm, height 50 mm) under the action of braking radiation from electrons with energies of 4 to 8 MeV in order to determine the effect of target form and orientation relative to the detector upon the recorded photoneutron level. The fluxes were measured by an all-wave neutron detector based on an SNM-11 counter in a paraffin retarder at an angle of 90 to the axis of the braking radiation beam for various target orientations relative to the detector. Measurement results are compared to calculations. Photoneutron fluxes from heavy water and beryllium targets of the indicated dimensions were also measured for angles of 90, 135, and 167. An isotropic nature was noted in the photoneutron fluxes from both targets.Deceased.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 5–9, September, 1989.In conclusion, the authors express their gratitude to V. I. Lunev and B. M. Yakovlev for their assistance in performing the measurements. 相似文献
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Ter-Akopian G. M. Oganessian Yu. Ts. Bezbakh A. A. Fomichev A. S. Golovkov M. S. Gorshkov A. V. Krupko S. A. Nikolskii E. Yu. Sidorchuk S. I. Stepantsov S. V. Wolski R. 《Physics of Atomic Nuclei》2020,83(4):497-502
Physics of Atomic Nuclei - Quasi-elastic, multi-nucleon transfer reactions induced by the radioactive-ion beams with energy 4–6 MeV/u allow one to produce moderately excited neutron-rich... 相似文献
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Korsheninnikov AA Golovkov MS Tanihata I Rodin AM Fomichev AS Sidorchuk SI Stepantsov SV Chelnokov ML Gorshkov VA Bogdanov DD Wolski R Ter-Akopian GM Oganessian YT Mittig W Roussel-Chomaz P Savajols H Kuzmin EA Nikolskii EY Ogloblin AA 《Physical review letters》2001,87(9):092501
Experimental search for (5)H using a secondary beam of (6)He has been performed. The transfer reaction (1)H((6)He,(2)He)(5)H was studied by detecting two protons emitted from the decay of (2)He. A peak consistent with a (5)H resonance at 1.7+/-0.3 MeV above the n+n+t threshold was observed, with a width of 1.9+/-0.4 MeV. The angular distribution of the (1)H((6)He,(2)He)(5)H reaction was measured as well as the energy correlation of the two protons. 相似文献
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D. A. Artemenkov A. A. Bezbakh V. Bradnova M. S. Golovkov A. V. Gorshkov P. I. Zarubin I. G. Zarubina G. Kaminski N. K. Kornegrutsa S. A. Krupko K. Z. Mamatkulov R. R. Kattabekov V. V. Rusakova R. S. Slepnev R. Stanoeva S. V. Stepantsov A. S. Fomichev V. Chudoba 《Physics of Particles and Nuclei Letters》2013,10(5):415-421
Nuclear track emulsion is exposed to a beam of radioactive 8He nuclei with an energy of 60 MeV and enrichment of about 80% at the ACCULINNA separator. Measurements of 278 decays of the 8He nuclei stopped in the emulsion allow the potential of the α spectrometry to be estimated and the thermal drift of 8He atoms in matter to be observed for the first time. 相似文献
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<正>Two new eudesmane derivatives were isolated from the leaves and flowers of Verbesina virginica,along with the known 6-O-β-E -p-coumaroyl-4α-hydroxyeudesmane(1).Their structures were determined as 6-O-β-Z-p-coumaroyl-4α-hydroxyeudesmane(2) and 6-O-α-E-p-coumaroyl-1β-4α-dihydroxyeudesmane(3) by spectroscopic methods. 相似文献
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G. M. Ter-Akopian D. D. Bogdanov A. S. Fomichev M. S. Golovkov Yu. Ts. Oganessian A. M. Rodin S. I. Sidorchuk R. S. Slepnev S. V. Stepantsov R. Wolski V. A. Gorshkov M. L. Chelnokov A. A. Korsheninnikov E. Yu. Nikolski I. Tanihata F. Hanappe T. Materna L. Stuttge A. H. Ninane 《Physics of Atomic Nuclei》2003,66(8):1544-1551
To investigate 5H resonance states with a better instrumental resolution, we utilized the two-neutron transfer reaction 3H(t, p)5H accomplished with the use of a cryogenic liquid-tritium target and 57.5-MeV triton beam. As a result of this study, a valuable fraction of protons detected at ? lab=18°–32° in ptn coincidence events was attributed to the states of the 5H nucleus. Two resonance states situated at 1.8±0.1 and 2.7±0.1 MeV above the t + n + n decay threshold were obtained in the missing mass energy spectrum of the 5H nucleus. The peak located close to E5H was clearly seen in the 5H spectrum obtained from the energy distributions of 3H nuclei emitted in the reaction 2H(6He, 5H)3He at ? lab=17°–32°. The width (Γobs≤0.5 MeV) obtained for the two 5H resonance states is surprisingly small. A state of 4H with E res=3.3 MeV and γ 2=2.3 MeV was obtained in the reaction 2H(t, p)4H from the spectra of protons leaving the target at ? lab=18°–32° and detected in coincidence with neutrons emitted in the decay of 4H nuclei. 相似文献
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CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
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John W.Grove 《数学物理学报(B辑英文版)》2010,30(2):563-594
This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described. 相似文献