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1.
Thermodynamic stability conditions for nanoparticles (resulting from non-negativity of the second variation of the free energy)
have been analyzed for two cases: (i) a nonvolatile nanosized particle with the size-dependent surface tension; (ii) the limiting
case of larger objects when the surface tension takes its macroscopic value. It has been shown that the mechanical stability
of a nanoparticle, i.e. its stability relative to the volume fluctuations, is defined by an interplay between the excess (“surface”)
free energy and the volumetric elastic energy. According to the results obtained, noble gas clusters and metal nanoparticles
satisfy the mechanical stability condition. At the same time, water nanodrops, as well as nanoparticles presented by nonpolar
organic molecules, correspond to the stability limit. Among the investigated systems, the stability condition is not carried
out for n-Pentane clusters. 相似文献
2.
The electronic structure, elastic constants, Poisson's ratio, and phonon dispersion curves of UC have been systematically investigated from the first-principles calculations by the projector-augmented-wave (PAW) method. In order to describe precisely the strong on-site Coulomb repulsion among the localized U 5f electrons, we adopt the local density approximation (LDA)+U and generalized gradient approximation (GGA)+U formalisms for the exchange correlation term. We systematically study how the electronic properties and elastic constants of UC are affected by the different choice of U as well as the exchange-correlation potential. We show that by choosing an appropriate Hubbard U parameter within the GGA+U approach, most of our calculated results are in good agreement with the experimental data. Therefore, the results obtained by the GGA+U with effective Hubbard parameter U chosen around 3 eV for UC are considered to be reasonable. 相似文献
3.
4.
F. Heine T. Faestermann A. Gillitzer J. Homolka M. Köpf W. Wagner 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(2):225-226
In fusion reactions of58Ni beams with54Pe and58Ni target nuclei neutron deficient evaporation residues have been produced and separated from the beam in an electrostatic deflector with large acceptance. The recoil nuclei were implanted and detected in an array of 100 PIN photodiodes, where also their particle decays were recorded. The assignment of the 0.81 MeV proton line to the decay of109I could be experimentally proven by the observation, that it is followed by the 3.31 MeV alpha emission from108Te. A proton decay from112Cs was not observed. The decay energies of a number of known emitters have been measured with better precision.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献
5.
L. S. Geng E. Oset J. R. Peláez L. Roca 《The European Physical Journal A - Hadrons and Nuclei》2009,39(1):81-87
By describing within the chiral unitary approach the s -wave interaction of the vector meson nonet with the octet of pseudoscalar Goldstone bosons, we find that the main component
of the axial-vector mesons --b
1(1235) , h
1(1170) , h
1(1380) , a
1(1260) , f
1(1285) and the two states associated to the K
1(1270) -- does not follow the QCD dependence on the number of colors for ordinary q
mesons. 相似文献
6.
The problem of size dependence of surface tension was investigated in view of a more general problem of the applicability
of Gibbs’ thermodynamics to nanosized objects. For the first time, the effective surface tension (coinciding with the specific
excess free energy for an equimolecular dividing surface) was calculated within a wide temperature range, from the melting
temperature to the critical point, using the thermodynamic perturbation theory. Calculations were carried out for Lennard-Jones
and metallic nanosized droplets. It was found that the effective surface tension decreases both, with temperature and particle
size. 相似文献
7.
Liudvikas Pranevičius Darius Milčius Liudas Pranevičius Vaiva Širvinskaitë Jurgita Nomgaudyte Jean-Paul Rivier Claude Templier 《Central European Journal of Physics》2004,2(1):67-89
This paper presents a generalized approach to the mechanisms of oxidation, hydrogenation and nitriding of metals under ion
irradiation with reactive particles at elevated temperatures. Experimental results on the plasma oxidation of bilayered Y/Zr
films, the plasma hydrogenation of Mg films and the ion beam (1.2 keV N
2
+
) nitriding of stainless steel are presented and discussed. We make special emphasis on the analysis of surface effects and
their role in the initiation of mixing of bilayered films, the ingress of reactive species in the bulk and the restructuring
of the surface layers. It is suggested that primary processes driving reactive atoms from the surface into the bulk are surface
instabilities induced by thermal and ballistic surface atom relocations under reactive adsorption and ion irradiation, respectively.
The diffusion of adatoms and vacancies, at temperature when they become mobile, provide the means to relax the surface energy.
It is recognized that the stabilizing effect of surface adatom diffusion is significant at temperatures below 300–350°C. As
the temperature increases, the role of surface adatom diffusion decreases and processes in the bulk become dominant. The atoms
of subsurface monolayers occupy energetically favorable sites on the surface, and result in reduced surface energy. 相似文献
8.
9.
Yu-Feng Zhou 《The European Physical Journal C - Particles and Fields》2008,58(2):301-309
The effects of flavor mixing in electroweak baryogenesis is investigated in a generalized semiclassical WKB approach. Through
calculating the non-adiabatic corrections to the particle currents, it is shown that extra CP violation sources arise from
the off-diagonal part of the equation of motion of particles moving inside the bubble wall. This type of mixing-induced source
is of first order in a derivative expansion of the Higgs condensate, but it is oscillation suppressed. The numerical importance
of the mixing-induced source is discussed in the minimal supersymmetric standard model and compared with the source term induced
by a semiclassical force. It is found that in a large parameter space where oscillation suppression is not strong enough,
the mixing-induced source can dominate over that from the semiclassical force. 相似文献
10.
利用磁控溅射方法在不同溅射压强条件下制备了TiN/SiNx纳米多层膜.多层膜的微观结构及力学性能分别用X射线衍射仪、原子力显微镜及纳米压痕仪来表征.结果表明随着溅射压强的增大,多层膜的界面变模糊,TiN层的择优取向由(200)晶面过渡到(111)晶面.与此同时,多层膜的表面粗糙度增大,硬度和弹性模量随溅射压强的增大而减小.多层膜力学性能的差异主要是由于薄膜的周期性结构及致密度存在差异所致.
关键词:
x多层膜')" href="#">TiN/SiNx多层膜
界面宽度
表面形貌 相似文献
11.
T. Branz T. Gutsche V. Lyubovitskij 《The European Physical Journal A - Hadrons and Nuclei》2008,37(3):303-317
We discuss a possible interpretation of the f
0(980)-meson as a hadronic molecule —a bound state of K and mesons. Using a phenomenological Lagrangian approach we calculate the strong f
0(980) → ππ and electromagnetic f
0(980) → γγ decays. The compositeness condition provides a self-consistent method to determine the coupling constant between
f
0 and its constituents, K and . Form factors governing the decays of the f
0(980) are calculated by evaluating the kaon loop integrals. The predicted f
0(980) → ππ and f
0(980) → γγ decay widths are in good agreement with available data and results of other theoretical approaches. 相似文献
12.
Kaname Kanai Kouki Akaike Kiichirou Koyasu Kentaro Sakai Toshio Nishi Yasunori Kamizuru Tatsuhiko Nishi Yukio Ouchi Kazuhiko Seki 《Applied Physics A: Materials Science & Processing》2009,95(1):309-313
The unoccupied π
* states of the solid film of electron accepting organic molecules, 7,7,8,8-tetracyanoquinodimethane (TCNQ), fluorinated TCNQ
derivatives, 11,11,12,12-tetracyanonaphtho-2,6-quinodimethane (TNAP), C60, and 6,6-phenyl-C61-butyric acid methyl ester (PCBM) have been studied by inverse photoemission spectroscopy. The assignment of the π
* affinity levels of these typical electron accepting molecules provides the basic information for the organic electronics
and the new electronic functional molecular design. The comparison with density functional theory calculations enables understanding
how the electron affinity evolves in terms of molecular orbitals. The correlation between the film morphology and the irradiation
damage on the TCNQ derivative samples by electron impact during the inverse photoemission measurements is also discussed. 相似文献
13.
We use the phase space position-velocity (x, v) to deal with the statistical properties of velocity dependent dynamical systems, like dissipative ones. Within this approach,
we study the statistical properties of an ensemble of harmonic oscillators in a linear weak dissipative media. Using the Debye
model of a crystal, we calculate at first order in the dissipative parameter the entropy, free energy, internal energy, equation
of state and specific heat using the classical and quantum approaches. For the classical approach we found that the entropy,
the equation of state, and the free energy depend on the dissipative parameter, but the internal energy and specific heat
do not depend of it. For the quantum case, we found that all the thermodynamical quantities depend on this parameter.
PACS: 05.20.Gg, 05.30.Ch, 05.20.-y, 05.30.-d 相似文献
14.
R. Steinigeweg J. Gemmer H.-P. Breuer H.-J. Schmidt 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(2):275-287
We discuss the time-convolutionless (TCL) projection operator approach to transport in closed quantum systems. The projection
onto local densities of quantities such as energy, magnetization, particle number, etc. yields the reduced dynamics of the
respective quantities in terms of a systematic perturbation expansion. In particular, the lowest order contribution of this
expansion is used as a strategy for the analysis of transport in “modular” quantum systems corresponding to quasi one-dimensional
structures which consist of identical or similar many-level subunits. Such modular quantum systems are demonstrated to represent
many physical situations and several examples of complex single-particle models are analyzed in detail. For these quantum
systems lowest order TCL is shown to represent an efficient tool which also allows to investigate the dependence of transport
on the considered length scale. To estimate the range of validity of the obtained equations of motion we extend the standard
projection to include additional degrees of freedom which model non-Markovian effects of higher orders. 相似文献
15.
We perform a linear analysis of the Marangoni instability of a deformable interface between two fluid layers of finite depths,
submitted to a gradient of solvent concentration induced by evaporation at the top layer, in the presence of convective as
well as diffusive solvent transport. We discuss, in turn, the influence on the onset of the instability of the solvent evaporation
rate, of the ratios of viscosity and diffusivity, of the rate of convection and of the layer depths. Qualitative comparison
with experimental observations of spin-coating processes of solution of two immiscible polymers are then performed, yielding
satisfactory agreement. 相似文献
16.
V. M. Samsonov A. N. Bazulev N. Yu. Sdobnyakov 《Central European Journal of Physics》2003,1(3):474-484
The problem of applicability of thermodynamics to small objects has been investigated. It is shown that the Gibbs surface
phase method may be extended to nanoparticles if the effective surface tension (the specific excess free energy) is interpreted
as a function of the particle radius.
Dedicated to the Centennial of J.W. Gibb's Death 相似文献
17.
R. Proietti Zaccaria S. Shoji H.-B. Sun S. Kawata 《Applied physics. B, Lasers and optics》2008,93(1):251-256
A mathematical scheme capable of describing the features of the photolithographic multi-beam–multi-shot approach is introduced
here. We will show in detail how such a technique can reproduce any of the fourteen three-dimensional Bravais lattices. Furthermore,
we will mathematically show the independence of the lattice constant of the structure from the laser wavelength. Finally,
we will compare the four-beams–one-shot and the three-beams–three-shots techniques by means of simulations reproducing opal
and connected FCC-like lattices. 相似文献
18.
J.G. Peixoto de Faria 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):153-162
We present the general solutions for the classical and quantum
dynamics of the anharmonic oscillator coupled to a purely
diffusive environment. In both cases, these solutions are obtained by
the application of the Baker-Campbell-Hausdorff (BCH) formulas to
expand the evolution operator in an ordered product of
exponentials. Moreover, we obtain an expression for the Wigner
function in the quantum version of the problem. We observe that
the role played by diffusion is to reduce or to attenuate the
the characteristic quantum effects yielded by the nonlinearity,
as the appearance of coherent superpositions of quantum states
(Schr?dinger cat states) and revivals. 相似文献
19.
A. Hassanien M. Tokumoto A. Mrzel D. Mihailovic H. Kataura 《Physica E: Low-dimensional Systems and Nanostructures》2005,29(3-4):684
Using a scanning probe microscope, we investigate the structure, electronic and mechanical properties of MoS2–Ix nanotubes and Mo6SxIy nanowires. The electronic properties are interestingly very sensitive to the stoichiometry of the nanowires, which can be controlled by adjusting the synthesis conditions. In addition to that, we find also remarkable mechanical properties where molecules can be cut and recombined or deformed without any loss of structural integrity. We demonstrate this by deforming Mo6SxIy nanowires to highly strained configurations without causing irreversible changes to their structures. The rupturing and/or welding process of these nanowires, using AFM manipulation, shows that the molecules stretch to more than 30% of its relaxed configuration before plastic deformation occurs. 相似文献