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1.
The method is described and the experimental results are presented on the temperature determination of the (CF3I)
N
clusters in a beam (N ⩽ 102 is a number of monomers in a cluster) using SF6 molecules from intersecting molecular beam as probe thermometers. The SF6 molecules are captured by clusters in the crossed cluster and molecular beams and, after a certain time, sublimate from the
surface of clusters carrying information on the velocity and temperature (internal energy) of clusters. Using time-of-flight
(TOF) method the kinetic energy (velocity) of sublimated SF6 molecules was measured and the temperature of clusters was determined to be T
cl = (88 ± 15) K. 相似文献
2.
V. I. Petinov 《Technical Physics》2017,62(6):882-889
Influence of temperature and magnetic field H on magnetism of spherical Gd nanoparticles of different sizes (89, 63, 47, 28, and 18 nm) was studied in the temperature range 250 K < T < 325 K. The particles were obtained by metal vapor condensation in the flow of helium. The particles with d = 18 nm did not show a magnetic transition; their structure is a combination of two cubic phases (FCC1 and FCC2). Large particles remained in the HCP phase and had an admixture of the FCC1 phase, the amount of which decreased as the particle sizes increased; magnetic transition took place at T c = 293 K. The admixture of O2 did not alter the structure but decreased the magnetization σ and magnetic permeability μ. An orientation transition in polycrystalline gadolinium initiated by the magnetic field H was proved in an experiment. The orientation transition in Gd particles smaller than 63 nm, the magnetic structure of which is close to the single-domain structure, occurred near T c without the influence of H. 相似文献
3.
4.
J. L. Goity 《Physics of Atomic Nuclei》2005,68(4):624-633
The 1/N c -power countings for baryon decays and configuration mixings are determined by means of a nonrelativistic quark picture. Such countings are expected to be robust under changes in the quark masses and, therefore, valid as these become light. It is shown that excited baryons have natural widths of \(\mathcal{O}(N_c^0 )\). These dominant widths are due to the decays that proceed directly to the ground-state baryons, with cascade decays being suppressed to \(\mathcal{O}(1/N_c )\). Configuration mixings, defined as mixings between states belonging to different O(3) × SU(2N f ) multiplets, are shown to be subleading in an expansion in \(1/\sqrt {N_c }\) when they involve the ground-state baryons, while the mixings between excited states can be \(\mathcal{O}(N_c^0 )\). 相似文献
5.
Saskia Mioduszewski 《The European Physical Journal C - Particles and Fields》2009,61(4):741-745
Results on high-p
T
probes shown at the Hard Probes 2008 Conference are summarized, with an appreciation of the improvements in precision of
the measurements and experimental techniques since the beginning of RHIC operation. Particular attention is given to the latest
measurements of the nuclear modification factor of identified particles, photon-hadron correlation measurements, and full
jet reconstruction. 相似文献
6.
V. V. Pokropivny L. I. Ovsyannikova S. V. Kovrigin 《Physics of the Solid State》2007,49(12):2335-2341
A general approach is formulated to the design of crystal-forming fullerene-like clusters X n Y n from which zeolite-like covalent crystals based on IV-IV, III-V, and II-VI binary semiconductor compounds with diamond-like sp 3 bonds can be constructed and synthesized by means of copolymerization through faces. A number of the smallest sized crystal-forming boron nitride clusters are constructed, such as the B12N12, B16N16, B18N18, B24N24, B36N36, and B 60N60 fulborenes. The optimized configurations, electronic structures, charge transfers, band gaps, total energies, cohesive energies, and electron density maps of the clusters are calculated using the spin-restricted Hartree-Fock method in the 6–31G basis set. Comparative calculations of the B60N60 fulborene with the use of the density functional theory method have demonstrated that the spin-restricted Hartree-Fock method in the 6–31G basis set is optimum from the standpoint of the accuracy and efficiency. 相似文献
7.
8.
During the last decade, as the experimental and computing means and techniques have rapidly evolved, the experimental investigation of the f7/2-shell nuclei has gained renewed interest. TheN = Z nuclei studied with the GASP array range from 44Ti to 52Fe. The results extended the knowledge of their structure up to high spins and excitation energies, above band terminations, where the competition with the charged-particles emission was initially thought to obscure the possibility of gamma-ray spectroscopy investigation. The paper highlights some of the most outstanding properties of these nuclei such as the nuclear rotation and backbending effects, band termination states, yrast traps, non-natural parity bands, competition between T = 0 and T = 1 pn pairing modes.Received: 30 October 2002, Published online: 16 March 2004PACS:
21.10.-k Properties of nuclei; nuclear energy levels - 21.60.Cs Shell model - 23.20.Lv
transitions and level energies - 27.40. + z
C.A. Ur: On leave from NIPNE Bucharest, Romania 相似文献
9.
S.?R.?Gevorkyan A.?N.?Sissakian A.?V.?Tarasov H.?T.?Torosyan O.?O.?Voskresenskaya 《Physics of Atomic Nuclei》2010,73(6):937-940
The final-state interaction of pions in K e4 decay allows to obtain the value of the isospin and angular-momentum-zero ππ scattering length a 0 0 .We take into account the electromagnetic interaction of pions and isospin-symmetry-breaking effects caused by different masses of neutral and charged pions and estimate the impact of these effects on the procedure of scattering-length extraction from K e4 decays. 相似文献
10.
S. R. Gevorkyan A. N. Sissakian A. V. Tarasov H. T. Torosyan O. O. Voskresenskaya 《Physics of Atomic Nuclei》2010,73(6):961-964
The final-state interaction of pions in K
e4 decay allows to obtain the value of the isospin and angular-momentum-zero ππ scattering length a
00.We take into account the electromagnetic interaction of pions and isospin-symmetry-breaking effects caused by different masses
of neutral and charged pions and estimate the impact of these effects on the procedure of scattering-length extraction from
K
e4 decays. 相似文献
11.
In this proceeding, we present our recent work on decay behaviors of the Pc hadronic molecules, which can help to disentangle the nature of the two Pc pentaquark-like structures. The results turn out that the relative ratio of the decays of P c + (4380) to \({\bar D *}{\Lambda _c}\) and J/ψp is very different for Pc being a \({\bar D *}{\Sigma _c}\) or \(\bar D\Sigma _c *\) bound state with \({J^P} = \frac{{{3 - }}}{2}\) And from the total decay width, we find that Pc(4380) being a \(\bar D\Sigma _c *\) molecule state with \({J^P} = \frac{{{3 - }}}{2}\) and Pc(4450) being a \({\bar D *}{\Sigma _c}\) molecule state with \({J^P} = \frac{{{5 + }}}{2}\) is more favorable to the experimental data. 相似文献
12.
M. A. Braun 《The European Physical Journal C - Particles and Fields》2009,63(2):287-296
The lowest order pomeron loop is calculated for the leading conformal weight with full dependence of the triple-pomeron vertex
on intermediate conformal weights. The loop is found to be convergent. Its contribution to the pomeron Green function begins
to dominate already at rapidities 10–15. The pomeron pole renormalization is found to be quite small due to a rapid fall of
the triple-pomeron vertex with rising conformal weights. 相似文献
13.
We discuss the quantum state structure using the standard model for three colored quarks in the fundamental representations of SU(3)c making up the singlet ground state of the hadrons. This allows us to calculate a finite von Neumann entropy from the quantum reduced density matrix, which we explicitly evaluate for the quarks in a model for the meson and baryon states.Received: 9 December 2003, Revised: 23 January 2004, Published online: 8 April 2004D.E. Miller: om0@psu.eduPermanent address: Department of Physics, Pennsylvania State University, Hazleton Campus, Hazleton, Pennsylvania, 18201 USA 相似文献
14.
The hierarchical structure of fermion masses of the Standard Model is explained in split fermion models by localizing the
fermions at different points in an extra dimension. We consider split fermion models with two bulk scalars compactified on an orbifold. In the static case we find analytical expression for the localizer. We also address the issue of stability of the localizer.
We also find exact solutions for the fermion zero modes. We explore the parameter space of the model. We find ample opportunity
for construction of phenomenologically viable theories exist. 相似文献
15.
The general features of particle production in hadron-hadron and hadron-nucleus collisions at high energy and transverse momentum using the concept of z-scaling are reviewed. z-Presentation of experimental data on the inclusive cross sections obtained at ISR, SPS, and Tevatron is presented and its properties are discussed. It is argued that the properties reflect the fundamental symmetries such as self-similarity, locality, and fractality. z-Scaling is used to predict particle yields in hadron-hadron and hadron-nucleus collisions at RHIC and LHC energies. The violation of z-scaling is considered as a signature of new physics phenomena. 相似文献
16.
From a macroscopic theory of the quantum vacuum in terms of conserved relativistic charges (generically denoted by q
(a) with label a), we have obtained, in the low-energy limit, a particular type of f(R) model relevant to cosmology. The macroscopic quantum-vacuum theory allows us to distinguish between different phenomenological
f(R) models on physical grounds.
The text was submitted by the authors in English. 相似文献
17.
J. P. Guedes S. Azevedo M. Machado 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,80(1):127-135
We have studied, through ab initio calculations, the stability of 60° and 120° boron nitride nanocones containing mono and
multiple boron, nitrogen, and
carbon vacancies. The stability of the vacancies as well as the structures reconstruction mechanism have been investigated.
Our results indicate that the
stability of the cones presenting such vacancies strongly depends on growth conditions. We have also found that multiple vacancies
display formation energies that
are comparable, and in some cases, even lower to the ones presented by monovacancies. Therefore, our results allow us to conclude
that the formation energy does not
depend on the vacancy size. Finally, for 120° cones, we can verify that the stability of the boron and nitrogen vacancies
depends on the position where the atom has
been removed. 相似文献
18.
N. E. Hussey J. R. Cooper Chen Changkang J. W. Hodby 《Czechoslovak Journal of Physics》1996,46(3):1201-1202
Low-field magnetizationM(H) measurements can be used to probe the nature of the screening currents and the interlayer coupling in high-T c cuprates. Here we compare theM(H) behaviour of single crystals of Bi2Sr2CaCu2O8 and fully oxygenated and oxygen reduced YBa2Cu3O7??. In YBa2Cu3O7, theM(H) behaviour is consistent with anisotropic 3D superconductivity whilst in Bi2Sr2CaCu2O8, the surface screening currents are strongly affected by the presence of vortices, implying that the CuO2 planes are coupled via a weak Josephson interaction. In oxygen-deficient YBa2Cu3O6.7 (T c =63K), theM(H) behaviour at low temperatures is similar to that found for Bi2Sr2CaCu2O8, implying that the removal of oxygen from the chains has resulted in a dimensional crossover of the superconducting state in YBa2Cu3O7??. As the temperature approachesT c , the 3D behaviour is eventually restored as thec-axis coherence length ξ c becomes comparable with the interlayer spacingd. 相似文献
19.
Teng Wang Tianbo Liu Da-Xin Zhang Bo-Qiang Ma 《The European Physical Journal C - Particles and Fields》2011,71(9):1758
We investigate the rare decays \(B_{c} \rightarrow D_{s}(1968)\ell \overline{\ell}\) and \(B_{c}\rightarrow D_{s}^{*}(2317) \ell \overline{\ell}\) in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful for investigating the structure of B c meson and for testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC. 相似文献
20.
The spatial string tension across a crossover from the low-temperature phase to the high-temperature phase is computed in
QCD with two flavors of nonperturbatively improved Wilson fermions at small lattice spacing a ∼ 0.12 fm. We find that in the low-temperature phase spatial string tension agrees well with zero-temperature string tension.
Furthermore, it does not show increasing for temperatures up to T = 1.36T
pc, the highest temperature considered. Our results agree with some theoretical predictions.
The text was submitted by the authors in English. 相似文献