共查询到20条相似文献,搜索用时 31 毫秒
1.
L.C. Dennis K.R. Cordell R.R. Doering R.L. Parks S.T. Thornton J.L.C. Ford J.Gomez Del Campo D. Shapira 《Nuclear Physics A》1981,357(2):521-532
Excitation functions at 7° (lab) have been measured from Ec.m. = 5.1 to 11.4 MeV in approximately 114 keV steps for 15 groups of final states in 17O populated by the 12C(9Be, α) reaction. Statistical tests have been used to locate possible non-statistical structure in the excitation functions. Possible anomalies were found near Ec.m. = 6.3, 7.5, 8.9 and 9.7 MeV. Angular distributions were measured at Ec.m. = 9.20, 9.71 and 10.23 MeV for the three lowest excited states in 17O. The data have been compared with Hauser-Feshbach calculations in addition to the following reaction mechanisms: compound plus a single resonance, compound plus interfering resonances and compound plus direct reactions. 相似文献
2.
E. I. Pogorel’tsev S. V. Mel’nikova A. V. Kartashev M. S. Molokeev M. V. Gorev I. N. Flerov N. M. Laptash 《Physics of the Solid State》2013,55(3):611-618
The heat capacity, unit cell parameters, permittivity, optical properties, and thermal expansion of the (NH4)2TaF7 compound with a seven-coordinated anion polyhedron have been measured. It has been found that the compound undergoes two successive phase transitions with the symmetry change: tetragonal → (T 1 = 174 K) orthorhombic → (T 2 = 156 K) tetragonal. The ferroelastic nature of structural transformations has been established, and their entropy and susceptibility to hydrostatic pressure have been determined. 相似文献
3.
Energy spectra and differential cross sections of nitrogen products formed in the reaction 28 MeV 11B + 12C have been measured using a ΔE?E counter telescope. The energy spectra are smooth and therefore indicate that the nitrogen products were formed by a compound nucleus mechanism, via the formation and decay of the compound nucleus 23Na. The experimental results are compared with statistical model calculations and good agreement is obtained. This result provides further evidence for the importance of the compound nucleus mechanism in heavy ion reactions with light nuclei and also gives added validity to the statistical model for light compound systems. 相似文献
4.
W. Gruhle Th. Bauer T. H. Seligmann H. H. Hackenbroich 《Zeitschrift für Physik A Hadrons and Nuclei》1973,262(3):271-278
Excitation functions for16O(α,n) and20Ne(α,n) have been measured from threshold to 26 and 31 MeV compound excitation energy, respectively. The dominating compound states are interpreted as boson excitation modes of nuclei with α-particle structure. 相似文献
5.
Yu. V. Knyazev A. V. Lukoyanov Yu. I. Kuz’min S. Gupta K. G. Suresh 《Physics of the Solid State》2016,58(12):2373-2378
The results of the investigation of the electronic structure and optical properties of the TbMn0.33Ge2 compound have been presented. The spin-polarized calculations of the band spectrum have been performed within the framework of the local spin density approximation (LSDA) with a correction for strong correlations in the 4f shell of the rare-earth ion (the LSDA + U method). The optical constants have been measured using the ellipsometric method and a number of spectral and electronic characteristics of the compound under investigation have been determined over a wide range of wavelengths. The interband part of the experimental dependence of the optical conductivity has been interpreted using the results of the calculation of the electron density of states. 相似文献
6.
X-ray photoelectron spectroscopy characterization of the layered intercalated compound K2xMn1 − xPS3
Polycrystalline powders of the layered MnPS3 compound have been intercalated with K+ ions by ion-exchange to yield the K2xMn1 − xPS3 intercalate. X-ray photoelectron spectroscopy has been applied to learn about the electronic structure of this compound. In particular, we have studied the XPS spectra of the Mn 2p and 3p, P and S 2p, K 2p and 3p core levels and of the valence band region. The binding energies for various core levels of the elements present in this compound and their observed chemical shifts are analyzed. The data give evidence for the lack of non-equivalent atoms of K, Mn, P and S. Shake-up satellites are present at the Mn 2p and 3p core levels. The occurrence of such lines allows us to hypothesize that K2xMn1 − xPS3 is a large-gap insulating Mn compound. Confirmation that only an ion transfer accompanies the intercalation process is given from both the strong observed similarity with the corresponding XPS spectra in MnPS3 and the observed binding energy positions of the K 2p and 3p levels. As regards the valence band XPS spectrum, the observed analogies with the corresponding XPS spectra of the pure compound and of other K compounds have allowed us to single out two regions and their probable contributors. 相似文献
7.
《Journal of magnetism and magnetic materials》2001,234(1):114-117
A new ferrimagnetic compound with the chemical formula CaLaFe11O19 has been synthesized by solid state reaction between the respective oxides and their structural, electrical and magnetic properties have been studied. One magnetic Fe3+ ion in CaLaFe12O19 is replaced by La3+ ion. The crystallographic results show the compound is hexagonal magnetoplumbite. The electrical conductivity has been measured from 300 to 800 K. The activation energy changes at Curie temperature (653 K). The compound is ferrimagnetic from 300 to 653 K and above Tc it acts as a paramagnetic. Variation of inverse molar susceptibility has been measured at various temperature in paramagnetic region and Curie molar constant (Cm) is calculated. AC susceptibility measurements are made at room temperature. The Seebeck coefficient (S) measurements show that the compound is n-type. 相似文献
8.
A. Rivas F. Gonzalez‐Jimenez L. D'Onofrio E. Jaimes M. Quintero J. Gonzalez 《Hyperfine Interactions》1998,113(1-4):493-498
The Mössbauer measurements at variable temperature (from liquid helium to room temperature) on the layered compound CuFeTe2 have been able to determine the existence of a magnetically ordered state below T N= 254 ± 15 K. The general shape of the spectra and the magnitudes of the hyperfine fields let us to propose a Spin Density Wave (SDW) behavior for this compound. 相似文献
9.
The fine structure of a single crystal of the Zn0.9Ni0.1S cubic compound synthesized by the chemical transport method has been investigated at room temperature using thermal neutron diffraction. It has been found that the diffraction patterns of this compound, along with strong Bragg reflections of the facecentered cubic phase, include a system of diffuse maxima, which indicate the occurrence of a local deformation of the cubic structure by the Jahn-Teller nickel ions. Results of this experiment have been compared with the previously obtained data for the lightly doped Zn1 ? x Ni x Se single crystal (x = 0.002). 相似文献
10.
11.
S. S. Aplesnin L. V. Udod M. N. Sitnikov D. A. Velikanov M. V. Gorev M. S. Molokeev A. I. Galyas K. I. Yanushkevich 《Physics of the Solid State》2012,54(10):2005-2014
The compound Bi24(CoBi)O40 has been synthesized using the solid-phase reaction method. The temperature and field dependences of the magnetic moment in the temperature range 4 K < T < 300 K and the temperature dependences of the EPR line width and g-factor at temperatures 80 K < T < 300 K have been investigated. The electrical resistivity and thermoelectric power have been measured in the temperature range 100 K < T < 1000 K. The activation energy has been determined and the crossover of the thermoelectric power from the phonon mechanism to the electron mechanism with variations in the temperature has been observed. The thermal expansion coefficient of the samples has been measured in the temperature range 300 K < T < 1000 K and the qualitative agreement with the temperature behavior of the electrical resistivity has been achieved. The electrical and structural properties of the compound have been explained in the framework of the model of the electronic-structure transition with inclusion of the exchange and Coulomb interactions between electrons and the electron-phonon interaction. 相似文献
12.
T. V. Drokina G. A. Petrakovskii M. S. Molokeev D. A. Velikanov O. N. Pletnev O. A. Bayukov 《Physics of the Solid State》2013,55(10):2037-2042
Results of studying the specific features of formation of the crystal structure and distribution of iron cations over the sites in the DyFeTi2O7 compound have been presented and the comparison with the GdGaTi2O7 isostructural compound has been performed. The atomic disorder in the distribution of the Fe3+ ions over structural sites in the DyFeTi2O7 compound is confirmed by the Mössbauer spectroscopy and X-ray diffractometry. The results of magnetic measurements in the low-temperature region have revealed an inflection point in the temperature dependence of the magnetic moment and its dependence on the magnetic prehistory of the sample. The obtained experimental data suggest that there is a spin glass state with freezing point T f = 6 K in the DyFeTi2O7 compound. 相似文献
13.
B. Kohlmeyer F. Pühlhofer G. Sletten H. Freiesleben W. Schäfer W. F. W. Schneider R. Bock 《Zeitschrift für Physik A Hadrons and Nuclei》1981,301(4):349-352
A search forα-decay of high spin isomers in the mass range 140<A<200 is reported. Fusion reactions with beams of132Xe and50Ti have been used to provide high velocity recoils with angular momenta beyond 50?. Recoil distance experiments sensitive to half lives longer than 10 ps and shorter than about 1 ns have been performed for 31 different compound nuclei. Within a sensitivity of 1–30μb per event no delayedα-emission has been observed. 相似文献
14.
M. Diviš 《Physica B: Condensed Matter》2011,406(14):2898-2900
First-principles calculations based on density functional theory have been performed on the intermetallic compound NpNiSn. The electronic density of states, bonding properties and equilibrium volume have been studied using relativistic full-potential APW+lo calculations. The magnetocrystalline anisotropy energy has been estimated from total-energy calculations and the a-axis is predicted to be the easy axis of magnetization. The LSDA+U method has been employed to mimic the orbital polarization and to obtain the total magnetic moments. 相似文献
15.
Ayoub Kanaani Davood Ajloo Hamzeh Kiyani Mohamad Vakili Mahnaz Farahani Majid Amiri 《Optics and Spectroscopy》2016,121(2):246-252
4-((9,10-dioxo-9,10-dihydroanthracen-1-yl)oxy)-3-methoxybenzaldehyde has been synthesized in an attempt to obtain a new photochromic compound. The optimized molecular structure, mole fractions of title compound in trans and ana forms have been investigated. UV-visible spectra of the compound were also recorded. Upon irradiation with 300 nm light, the camel solid turned orange, in which a visible absorption band was observed at 475 nm. The electronic properties, such as HOMO, LUMO and band gap energies were obtained by the time-dependent DFT (TD-DFT) approach. The predicted nonlinear optical properties of the title compound are much greater than those of urea. Transition structures were calculated by QST3 and IRC methods which yielded the potential energy surface and activation energy. 相似文献
16.
T. Toliński B. Andrzejewski G. Che?kowska J. Fr?ckowiak 《Journal of Physics and Chemistry of Solids》2006,67(4):751-755
The magnetic, electrical and electronic properties of the tetragonal ternary YbFe4Al8 compound have been investigated. This compound was supposed to be an antiferromagnetic superconductor due to the negative magnetization signal appearing at a low field of the field cooling mode, however, based on the measurements of the temperature dependence of magnetization and resistivity we do not confirm the presence of superconductivity in this material and we ascribe the negative magnetization to the complicated non-collinear magnetic structure. A switch to the antiferromagnetic order at about 150 K has been visible both on the M(T) and ρ(T) curves. The valence state of the Yb ions has been studied by X-ray photoemission spectroscopy. The valence band spectrum at the Fermi level exhibits the domination of the hybridized Yb(4f) and Fe(3d) states. 相似文献
17.
《Journal of magnetism and magnetic materials》1987,69(3):305-310
Heat capacity, electrical resistivity and neutron diffraction studies have been performed on the tetragonal ternary compound NdRu2Ge2. Between temperatures of 17 and 10 K, the compound exhibits two types of sine-wave modulated magnetic structures, having wave vectors k = (0.19, 0.05, 0.125) and k = (0.12, 0.12, 0.0) with the amplitude of the moment along the c axis. Below 10 K, a first-order transition occurs to a ferromagnetic state with a moment of 3.64(13)μB aligned along the tetragonal axis. 相似文献
18.
The Schiff base (E)-1-[(3-(trifluoromethyl)phenylimino)methyl]naphthalen-2-olate was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 3-trifluoromethylaniline. The title compound has been characterized by FT-IR, UV-vis and X-ray single-crystal techniques. The present X-ray investigation shows that the compound exists in the zwitterionic form. Molecular geometry of the compound in the ground state have been calculated using the density functional method (DFT) with 6-31G(d,p) basis set and compared with the experimental data. The calculated results show that the optimized geometry can well reproduce the crystal structural parameters. By using TD-DFT method electronic absorption spectra of the compound have been predicted and a good agreement with the TD-DFT method and experimental one is determined. In addition DFT calculations of the compound, molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and non-linear optical (NLO) properties were performed at B3LYP/6-31G(d,p). 相似文献
19.
《Surface science》1993,291(3):L759-L762
Atomic force microscopy (AFM) has been used to image the surface structure of a CuCl2-graphite intercalation compound. We have obtained the first AFM image of CuCl2 molecules on a CuCl2GIC surface with an atomic resolution in air at room temperature, which shows an incommensurate superlattice structure (a = 0.39 nm) having a close resemblance to the bulk of this compound. 相似文献
20.
J.P. Boucher L.P. Regnault J. Rossat-Mignod J.P. Renard J. Bouillot W.G. Stirling 《Solid State Communications》1980,33(2):171-174
It is shown that magnetic solitons are expected to occur when a magnetic field is applied to a planar antiferromagnetic chain. Neutron inelastic scattering measurements have been performed at low energy on the one dimensional antiferromagnetic compound TMMC. A new fluctuation is observed, around q = π and ω = 0 which is well interpreted in terms of magnetic solitons. 相似文献