共查询到20条相似文献,搜索用时 31 毫秒
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2.
A. Merli F. Sauer L. Wöste A. Lindinger 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):217-220
We report on isotope selective three-photon ionization of
two isotopomers of KRb by applying evolution strategies. The
particularity of this experiment is based on the high resolution
phase and amplitude modulation of the fs-laser pulses provided by a
2 × 640 pixel pulse shaper. The optimization in a closed feedback
loop performed with spectrally broad pulses centered at 840 nm shows
high enhancements of one isotopomer at the expense of the other
isotopomer and vice versa. From the optimal laser field we aim to
gain details about the selective ionization sequence and the
wavepacket evolution on the involved vibrational states. 相似文献
3.
In this paper we present an expression relating the cohesive energy (E coh in kcal/mol) of AIIIBV and AIIBVI semiconductors with the product of ionic charges (Z 1 Z 2) and nearest-neighbour distance d (Å). The cohesive energy values of these solids exhibit a linear relationship when plotted on a log-log scale against the nearest-neighbour distance d (Å), but fall on different straight lines according to the ionic charge product of the solids. A good agreement has been found between the experimental and calculated values of the cohesive energy of AIIIBV and AIIBVI semiconductors. 相似文献
4.
Within the framework of the single-channel approximation, an {αtd} model of the 9
Be nucleus is presented. A comparative analysis of the t 6
Li wave functions describing relative motion of bound states constructed in {ααn} and {αtd} cluster representations is carried out on the example of calculations of the 9
Be(γ,t0)6
Li process characteristics.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 85–89, January, 2008. 相似文献
5.
S. S. Belyshev B. S. Ishkhanov V. V. Khankin A. A. Kuznetsov V. N. Orlin M. M. Popova K. A. Stopani 《Bulletin of the Russian Academy of Sciences: Physics》2018,82(6):702-707
The yields of photonuclear reactions on mixtures of natural isotopes of strontium and molybdenum that result in the formation and decay of bypassed nuclei 84Sr and 92Mo are measured and compared to theoretical results obtained using the TALYS code and calculations in the combined model of photonucleon reaction (CMPR). The need is demonstrated to consider isospin splitting in cases of photoproton reactions. The yields of the 92Mo(γ,p)91mNb, 84Sr(γ,p)83Rb reactions that make the main contribution to the formation and decay of 84Sr and 92Mo in the p-process of nucleosynthesis differ from the TALYS and CMPR results by several hundred percent. 相似文献
6.
A. Basu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(1):51-55
Electron-hydrogen scattering has been investigated in
Debye plasma environment employing the close-coupling approximation. Two
models, viz., 6-state CCA and 9-state CCA have been used. Plasma screening
has been taken into account via Debye-Hückel model potential. The
lowest lying 1De^1{\rm D}^{{\rm e}} auto-detaching resonance of the hydrogen negative
ion has been successfully predicted for various plasma conditions. The
resonant state changes to shape resonance for Debye scattering lengths less
than a critical value. 相似文献
7.
Aparajita Dey S. Bhattacharya C. Bhattacharya K. Banerjee T. K. Rana S. Kundu S. R. Banerjee S. Mukhopadhyay D. Gupta R. Saha 《The European Physical Journal A - Hadrons and Nuclei》2009,41(1):39-51
Inclusive energy distributions for light charged particles (p , d , t and have been measured in the 20Ne (158, 170, 180, 200 MeV) + 12C
reactionsintheangularrange$10°$ - - $50°$.Exclusivelight-charged-particleenergydistributionmeasurementswerealsodoneforthesamesystemat158 MeVbombardingenergybyin - planelightchargedparticle - - fragmentcoincidence.Pre - equilibriumcomponentshavebeenseparatedoutfromprotonenergyspectrausingthemovingsourcemodelconsideringtwosources.ThedatahavebeencomparedwiththepredictionsofthestatisticalmodelcodeCASCADE.Ithasbeenobservedthatsignificantdeformationeffectswereneededtobeintroducedinthecompoundnucleusinordertoexplaintheshapeoftheevaporated$d$,$t$energyspectra.Forprotons, evaporatedenergyspectrawereratherinsensitivetonucleardeformation, thoughangulardistributionscouldnotbeexplainedwithoutdeformation.Thedecaysequenceofthehot$32S$nucleushasbeeninvestigatedthroughexclusivelight - - charged - particlemeasurementsusingthe$20Ne$$(158 MeV) + $12C
reaction. Information on the sequential decay chain has been extracted through a comparison of the experimental data with
the predictions of the statistical model. It is observed from the present analysis that exclusive light-charged-particle data
may be used as a powerful tool to probe the decay sequence of hot light compound systems. 相似文献
8.
A. D. Pogrebnyak S. N. Bratushka L. V. Malikov N. Levintant N. K. Erdybaeva S. V. Plotnikov B. P. Gritsenko 《Technical Physics》2009,54(5):667-673
The surface layer of an equiatomic TiNi alloy, which exhibits the shape memory effect in the martensitic state, is modified
with high-dose implantation of 65-keV N+ ions (the implantation dose is varied from 1017 to 1018 ions/cm2). TiNi samples are implanted by N+, Ni+-N+, and Mo+-W+ ions at a dose of 1017–1018 cm−2 and studied by Rutherford backscattering, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction
(glancing geometry), and by measuring the nanohardness and the elastic modulus. A Ni+ concentration peak is detected between two maxima in the depth profile of the N+ ion concentration. X-ray diffraction (glancing geometry) of TiNi samples implanted by Ni+ and N+ ions shows the formation of the TiNi (B2), TiN, and Ni3N phases. In the initial state, the elastic modulus of the samples is E = 56 GPa at a hardness of H = 2.13 ± 0.30 GPa (at a depth of 150 nm). After double implantation by Ni+-N+ and W+-Mo+ ions, the hardness of the TiNi samples is ∼2.78 ± 0.95 GPa at a depth of 150 nm and 4.95 ± 2.25 GPa at a depth of 50 nm;
the elastic modulus is 59 GPa. Annealing of the samples at 550°C leads to an increase in the hardness to 4.44 ± 1.45 GPa and
a sharp increase in the elastic modulus to 236 ± 39 GPa. A correlation between the elemental composition, microstructure,
shape memory effect, and mechanical properties of the near-surface layer in TiNi is found. 相似文献
9.
Pierre-Jean Nacher Eric Stoltz Geneviève Tastevin 《Czechoslovak Journal of Physics》1996,46(6):3025-3032
Laser optical pumping in low magnetic field provides very high nuclear polarizations in gaseous helium mixtures, and is used to prepare polarized liquid. Wall relaxation in glass cells is effiently reduced using cesium coatings, and bulk longitudinal relaxation times are measured. In highly magnetized samples, dipolar fields control the spin dynamics in anisotropic volumes and weak external magnetic field inhomogeneities. Long lived magnetostatic modes are observed by pulsed NMR. Detailed analysis of their frequency and damping gives information on magnetization density and spin diffusion coefficient in polarized mixtures. Experiments are performed above 0.2 K on mixtures with3He concentrations of order a few percents or larger. When phase separation occurs, the3He-rich phase retains a high polarization. 相似文献
10.
A. V. Eliseev I. N. Meshkov V. A. Mikhailov A. O. Sidorin 《Physics of Particles and Nuclei Letters》2010,7(7):473-477
The main objective of the NICA project developed at the Joint Institute for Nuclear Research (JINR) is to conduct experimental
studies with colliding heavy ion beams in an energy range of 1–4.5 GeV/nucleonucleon with luminosity on the level of 1 × 1027 cm−2 s−1. In this paper the operation regime of the collider injection chain providing the bunch with experimentally desirable parameters
at the output of the Nuclotron is considered for gold ions as an example. 相似文献
11.
V. V. Varlamov B. S. Ishkhanov V. N. Orlin N. N. Peskov 《Physics of Atomic Nuclei》2016,79(4):501-513
Basic methods for determining cross sections for photoneutron partial reactions are examined. They are obtained directly in experiments with quasimonoeneregetic annihilation photons or from the cross section for the (γ, xn) = (γ, 1n) + 2(γ, 2n) + 3(γ, 3n) +... neutron-yield reaction in experiments with bremsstrahlung photons by introducing corrections based on statistical nuclear-reaction theory. The difference in the conditions of these experiments, which leads to discrepancies between their results because of sizable systematic errors, is analyzed. Physical criteria are used to study the reliability of data on the photodisintegration of 133Cs, 138Ba, and 209Bi nuclei. The cross sections for partial and total reactions satisfying the reliability criteria are evaluated within the experimental–theoretical method (σeval(γ, in) = Fitheor × σexpt(γ, xn)) on the basis of the experimental cross sections σexpt(γ, xn) and the results of the calculations within the combined model of photonuclear reactions. 相似文献
12.
We have investigated the photoluminescence (PL) and photostimulated luminescence (PSL) spectra at 300 K to study the effect
of isoelectronic impurities K+ and I− on the formation and energy structure of Eu2+-VCs isolated dipole centers and aggregate centers in the form of single crystals of CsEuBr3 in CsBr:Eu2+ single crystals. We have shown that K+ and I− impurities in a concentration of 5 mol% do not have a substantial effect on the energy spectrum of isolated dipole centers
in CsBr:Eu2+ single crystals and the processes for the formation of such centers during growth of CsBr:Eu single crystals from the melt
by the Bridgman method. We have established that in Cs0.95K0.05Br:Eu2+, more favorable conditions are realized for the formation of aggregate centers than in CsBr:Eu2+ and CsBr0.95K0.05Br:Eu2+ single crystals. So in order to improve the storage properties of phosphors based on CsBr:Eu2+, in particular for increasing the efficiency of PSL excitation, it is expedient to dope them with K+ impurity in a concentration up to 5 mol%.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 5, pp. 627–630, September–October, 2007. 相似文献
13.
Roland Beyer Arnd R. Junghans Peter Schillebeeckx Ivan Sirakov Tae-Yung Song Daniel Bemmerer Roberto Capote Anna Ferrari Andreas Hartmann Ronald Hannaske Jan Heyse Hyeon Il Kim Jong Woon Kim Toni Kögler Cheol Woo Lee Young-Ouk Lee Ralph Massarczyk Stefan E. Müller Tobias P. Reinhardt Marko Röder Konrad Schmidt Ronald Schwengner Tamás Szücs Marcell P. Takács Andreas Wagner Louis Wagner Sung-Chul Yang 《The European Physical Journal A - Hadrons and Nuclei》2018,54(5):81
14.
B. V. Zhuravlev A. A. Lychagin N. N. Titarenko V. G. Demenkov V. I. Trykova 《Physics of Atomic Nuclei》2011,74(3):335-340
The spectra of neutrons from the (p, n) reactions on 47Ti, 48Ti, 49Ti, 53Cr, and 54Cr nuclei were measured in the proton-energy range 7–11 MeV. The measurements were performed with the aid of a fast-neutron
spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and
Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used,
low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured
data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations
were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model
of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level
density. The nuclear level densities for 47V, 48V, 49V, 53Mn, and 54Mn were determined along with their energy dependences and model parameters. The results are discussed together with available
experimental data and recommendations of model systematics. 相似文献
15.
A.E. Dorokhov E.A. Kuraev Yu.M. Bystritskiy M. Sečanský 《The European Physical Journal C - Particles and Fields》2008,55(2):193-198
We reconsider QED radiative corrections (RC) to the π0→e+e- decay width. One kind of RC investigated earlier has a renormalization group origin and can be associated with the final
state interaction of electron and positron. It determines the distribution of lepton pair invariant masses in the whole kinematic
region. The other type of RC has a double-logarithmic character and is related to almost on-mass-shell behavior of the lepton
form factors. The total effect of RC for π0→e+e- decay is estimated to be 3.2%, and for η→e+e- decay it is 4.3%.
PACS 13.25.Cq; 12.38.Lg; 12.38.-t 相似文献
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N. G. Peresadko Yu. A. Alexandrov S. G. Gerasimov V. A. Dronov V. G. Larionova A. V. Pisetskaya E. I. Tamm V. N. Fetisov S. P. Kharlamov L. N. Shesterkina 《Physics of Atomic Nuclei》2010,73(11):1942-1947
In a track nuclear photoemulsion exposed to a beam of 7Li nuclei accelerated to a momentum of 3 GeV/c per nucleon at the synchrophasotron of the Joint Institute for Nuclear Research (JINR, Dubna), 13 events in which 7Li nuclei interacting with protons break up into 3H and 4He fragments were detected among 3730 inelastic-interaction events. For this fragmentation channel, the cross section was
found to be 8 ± 2 mb. The average value of the fragment total transverse momentum was 214 ± 5 MeV/c. This value exceeds markedly the average value of the transverse-momentum transfer in the coherent dissociation of 7Li nuclei on track-emulsion nuclei (166±5MeV/c). The recoil-proton transverse momentum was on average 98% of the total proton momentum. The longitudinal-momentum distribution
of protons was characterized by a variance of 16 MeV/c and a mean value of 37 ± 2MeV/c. 相似文献
18.
O. V. Bespalova I. N. Boboshin V. V. Varlamov T. A. Ermakova B. S. Ishkhanov E. A. Romanovskii T. I. Spasskaya T. P. Timokhina 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(3):428-433
The change in the neutron single-particle structure of (1f?2p)-shell magic nuclei near the Fermi energy with an increase in the number of protons in the 1f 7/2 subshell from 0 for 48Ca to 8 for 56Ni has been investigated. Good agreement of the experimental and estimated values of the single-particle energies E nlj of the bound states of neutrons in these nuclei with the results of calculations within the dispersive optical model is obtained. 相似文献
19.
Wei Jiang YanLin Ye ZhiHuan Li ChengJian Lin QiTe Li YuCheng Ge JianLing Lou DongXing Jiang Jing Li ZhengYang Tian Jun Feng Biao Yang ZaiHong Yang Jie Chen HongLiang Zang Qiang Liu PengJie Li ZhiQiang Chen Yun Zhang Yang Liu XiaoHui Sun Jing Ma HuiMing Jia XinXing Xu Lei Yang NanRu Ma LiJie Sun 《中国科学:物理学 力学 天文学(英文版)》2017,60(6):062011
A transfer-reaction experiment of 9Be(9Be, 10Be)8Be was performed at a beam energy of 45 MeV. Excited states in 10Be up to 18.80 MeV are produced using missing mass and invariant mass methods. Most of the observed high-lying resonant states, reconstructed from the α + 6He and t + 7Li decay channels, agree with the previously reported results. In addition, two new resonances at 15.6 and 18.8 MeV are identified from the present measurement. The 18.55 MeV state is found to decay into both the t + 7Lig.s. and t + 7Li* (0.478 MeV) channels, with a relative branching ratio of 0.93 ± 0.33. Further theoretical investigations are encouraged to interpret this new information on cluster structure in neutron-rich light nuclei. 相似文献
20.
M. A. Naumenko V. V. Samarin Yu. E. Penionzhkevich N. K. Skobelev 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(6):710-716
Experimental cross sections of formation of isotopes 46Sc (in reaction 6He + 45Sc), 196,198Au (in reaction 6He + 197Au), and 65Zn (in reaction 6He + 64Zn) are analyzed. The time-dependent Schrödinger equation for the outer neutrons of 6He and 197Au nuclei is solved numerically to calculate the probability of neutron transfer and transfer cross sections. In reaction 6He + 197Au, the contribution of fusion and subsequent evaporation to experimental data can be neglected, while the corresponding contributions to reactions 6He + 45Sc and 6He + 64Zn are considerable. Fusion–evaporation is taken into account using the computational code of the NRV knowledge base. The results of calculations are in satisfactory agreement with the experimental data. 相似文献