共查询到20条相似文献,搜索用时 78 毫秒
1.
Valentin Besse Alexandre Fortin Georges Boudebs Paula S. Valle Marcelo Nalin Cid B. de Araújo 《Applied physics. B, Lasers and optics》2014,117(3):891-895
The third-order optical properties of GeO2–Bi2O3–PbO–TiO2 glasses at 532 nm and 1,064 nm were studied to evaluate their potential for optical limiting and all-optical switching. The Z-scan technique was used to determine the nonlinear (NL) refractive index, n 2, and the NL absorption coefficient, α 2, of samples with different amounts of the constituent oxides. Values of n 2 ≈ + 0.7 × 10?14 cm2/W at 1,064 nm and ≈+1.5 × 10?14 cm2/W at 532 nm were measured. The NL absorption coefficient, α 2, was smaller than the minimum that our apparatus can measure (α 2 < 0.01 cm/GW) in the near-infrared (1,064 nm); in the visible region (532 nm), we obtained α 2 ≈ 4.4 cm/GW. The set of NL parameters measured indicates the potential usefulness of the GeO2–Bi2O3–PbO–TiO2 glasses for all-optical switching at 1,064 nm and for optical limiting at 532 nm. 相似文献
2.
A. Bolshakova I. Boyko G. Chelkov D. Dedovitch A. Elagin M. Gostkin S. Grishin A. Guskov Z. Kroumchtein Yu. Nefedov K. Nikolaev A. Zhemchugov F. Dydak J. Wotschack A. De Min V. Ammosov V. Gapienko V. Koreshev A. Semak Yu. Sviridov E. Usenko V. Zaets 《The European Physical Journal C - Particles and Fields》2009,62(4):697-754
We report on double-differential inclusive cross-sections of the production of secondary protons and charged pions, in the
interactions with a 5% λ
abs thick stationary beryllium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20° <θ<125°. 相似文献
3.
Michel Planat Anne-Céline Baboin Metod Saniga 《International Journal of Theoretical Physics》2008,47(4):1127-1135
The commutation relations of the generalized Pauli operators of a qubit–qutrit system are discussed in the newly established
graph-theoretic and finite-geometrical settings. The dual of the Pauli graph of this system is found to be isomorphic to the
projective line over the product ring
. A “peculiar” feature in comparison with two-qubits is that two distinct points/operators can be joined by more than one
line. The multi-line property is shown to be also present in the graphs/geometries characterizing two-qutrit and three-qubit
Pauli operators’ space and surmised to be exhibited by any other higher-level quantum system.
This work was partially supported by the Science and Technology Assistance Agency under the contract # APVT–51–012704, the
VEGA grant agency projects # 2/6070/26 and # 7012 (all from Slovak Republic), the trans-national ECO-NET project # 12651NJ
“Geometries over Finite Rings and the Properties of Mutually Unbiased Bases” (France) and by the CNRS–SAV Project # 20246
“Projective and Related Geometries for Quantum Information” (France/Slovakia). 相似文献
4.
K.?Bakke A.?M.?de?M.?Carvalho C.?Furtado 《The European Physical Journal C - Particles and Fields》2009,63(1):149-155
In this paper we discuss the Fermi–Walker transport of vectors along orbits in cosmic string and Schwarzschild–AdS spacetimes.
We analyze the influence of acceleration on these holonomies. An effect similar to Thomas precession is observed within the
process of Fermi–Walker transport along these circular orbits which are studied in the limit of vanishing cosmological constant
in Schwarzschild–AdS case; also we obtain Fermi–Walker transport in a Schwarzschild background. In the case of a Schwarzschild
spacetime, we analyze the quantized band holonomy invariance. In the limit of zero acceleration we recover the well-known
results for holonomy matrix obtained by parallel transport in all these spacetimes. 相似文献
5.
A. Bolshakova I. Boyko G. Chelkov D. Dedovitch A. Elagin M. Gostkin A. Guskov Z. Kroumchtein Yu. Nefedov K. Nikolaev A. Zhemchugov F. Dydak J. Wotschack A. De Min V. Ammosov V. Gapienko V. Koreshev A. Semak Yu. Sviridov E. Usenko V. Zaets 《The European Physical Journal C - Particles and Fields》2010,66(1-2):57-117
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ int thick stationary lead target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. Cross-sections on lead nuclei are compared with cross-sections on beryllium, copper, and tantalum nuclei. 相似文献
6.
ZnO–CuO core–shell nanorods and CuO-nanoparticle–ZnO-nanorod integrated structures were synthesized for the first time by
a two-stage solution process. Scanning electron microscopy and high-resolution transmission electron microscopy show that
the diameter and the length of the nanorods are around 60 and 800 nm, respectively. The morphologies of outer CuO could be
varied from nanoparticles to nanoshells by adjusting the solvent and dipping processes of copper (II) nitrate solution. The
CuO nanoparticles are single-crystalline or highly textured structures with size of around 30 nm. The CuO shell with thickness
of around 10 nm is constructed of nanocrystals with sizes in the range of 3–10 nm embedded in an amorphous matrix. Room-temperature
cathodoluminescence measurements of the CuO–ZnO nanocomposites exhibit relatively sharp ultraviolet emissions at 380 nm as
well as broad green and yellow emissions at 500 and 585 nm. The p-CuO/n-ZnO one-dimensional nanocomposites are promising for
optoelectronic nanodevice applications. 相似文献
7.
B. C. Anusionwu G. A. Adebayo C. A. Madu 《Applied Physics A: Materials Science & Processing》2009,97(3):533-541
The surface properties of Al–Ga and Al–Ge liquid alloys have been theoretically investigated at a temperature of 1100 K and
1220 K respectively. For the Al–Ga system, the quasi chemical model for regular alloy and a model for phase segregating alloy
systems were applied, while for the Al–Ge system the quasi chemical model for regular and compound forming binary alloys were
applied. In the case of Al–Ga, the models for the regular alloys and that for the phase segregating alloys produced the same
value of order energy and same values of thermodynamic and surface properties, while for the Al–Ge system, the model for the
regular alloy reproduced better the thermodynamic properties of the alloy. The model for the compound forming systems showed
a qualitative trend with the measured values of the thermodynamic properties of the Al–Ge alloy and suggests the presence
of a weak complex of the form Al2Ge3. The surface concentrations for the alloys show that Ga manifests some level of surface segregation in Al–Ga liquid alloy
while the surface concentration of Ge in Al–Ge liquid alloy showed a near Roultian behavior below 0.8 atomic fraction of Ge. 相似文献
8.
A. Bolshakova I. Boyko G. Chelkov D. Dedovitch A. Elagin D. Emelyanov M. Gostkin A. Guskov Z. Kroumchtein Yu. Nefedov K. Nikolaev A. Zhemchugov F. Dydak J. Wotschack A. De Min V. Ammosov V. Gapienko V. Koreshev A. Semak Yu. Sviridov E. Usenko V. Zaets 《The European Physical Journal C - Particles and Fields》2010,70(3):573-633
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ int thick stationary carbon target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. Cross-sections on carbon nuclei are compared with cross-sections on beryllium, copper, tantalum and lead nuclei. 相似文献
9.
10.
R. B. Nielsen M. D. Thoreson W. Chen A. Kristensen J. M. Hvam V. M. Shalaev A. Boltasseva 《Applied physics. B, Lasers and optics》2010,100(1):93-100
We report on the fabrication of two types of adjustable, near-field superlens designs: metal–dielectric composites and metal–dielectric
multilayer films. We fabricated a variety of films with different materials, thicknesses and compositions. These samples were
characterized physically and optically to determine their film composition, quality, and optical responses. Our results on
metal–dielectric composites indicate that although the real part of the effective permittivity generally follows effective
medium theory predictions, the imaginary part does not and substantially higher losses are observed. Going forward, it appears
that multilayer metal–dielectric designs are more suitable for sub-diffraction imaging applications because they could provide
both tunability and low loss. 相似文献
11.
S. Ritter F. Brennecke K. Baumann T. Donner C. Guerlin T. Esslinger 《Applied physics. B, Lasers and optics》2009,95(2):213-218
A Bose–Einstein condensate is dispersively coupled to a single mode of an ultra-high finesse optical cavity. The system is
governed by strong interactions between the atomic motion and the light field even at the level of single quanta. While coherently
pumping the cavity mode the condensate is subject to the cavity optical lattice potential whose depth depends nonlinearly
on the atomic density distribution. We observe optical bistability already below the single photon level and strong back-action
dynamics which tunes the coupled system periodically out of resonance. 相似文献
12.
N. Barreiro A. Vallespi A. Peuriot V. Slezak G. Santiago 《Applied physics. B, Lasers and optics》2010,99(3):591-597
A theoretical expression for the pulsed photoacoustic signal amplitude from NO2–air mixtures is deduced based on a two-level system and the inhomogeneous wave equation, in the limit where the V-T relaxation
time is longer than the laser pulse width (low buffer pressure). In this time limit, the photoacoustic signal from NO2, at constant pressure, after excitation by pulses from a Nd:YAG laser at 532 nm, is measured at different buffer pressures.
The relaxation rates are obtained by measuring the quenching of visible fluorescence induced by the same laser. The experimental
dependence of the photoacoustic signal amplitude on air pressure shows a very good agreement with the model, where the measured
relaxation rates are included. 相似文献
13.
Hans Christian ?ttinger 《Journal of statistical physics》2010,138(6):1067-1083
We elaborate and compare two approaches to nonequilibrium thermodynamics, the two-generator bracket formulation of time-evolution equations for averages and the macroscopic fluctuation theory, for a purely dissipative isothermal driven diffusive system under steady state conditions. The fluctuation dissipation relations of both approaches play an important role for a detailed comparison. The nonequilibrium Helmholtz free energies introduced in these two approaches differ as a result of boundary conditions. A Fokker-Planck equation derived by projection operator techniques properly reproduces long range fluctuations in nonequilibrium steady states and offers the most promising possibility to describe the physically relevant fluctuations around macroscopic averages for time-dependent nonequilibrium systems. 相似文献
14.
Single-crystalline Sb-doped Ge nanowires (NWs) with excellent structural properties and uniform composition have been synthesized
with high yield by vapor–liquid–solid (VLS) growth by low-temperature thermal evaporation from a mixture of Ge and Sb powders.
During deposition, both the Ge and the Sb dopant became incorporated in the VLS seed nanoparticle. In situ annealing experiments
during transmission electron microscopy establish that a liquid ternary Au-Sb-Ge alloy constitutes the active phase of the
VLS seed drop at high temperatures, which governs the growth of the one-dimensional Ge NW and its doping by Sb. 相似文献
15.
Li Xinying 《Molecular physics》2017,115(24):3128-3135
Theoretical investigations on the CuRnX and XCuRn (X = F – I) series have been performed at the CCSD(T) theoretical level. Analyses on dissociation energy and frontier orbital show a decreased trend of stabilities down the periodic table. NBO analyses show the existence of σCu-Rn and σCu-X bonding orbital resulted from the overlap between Cu spd hybrid and Rn/X sp hybrid. The Cu–Rn, Cu–X and Rn–X interactions characterised by negative energy density values, positive Laplacian values and small electron densities at bond critical point (BCP) can be described as interactions of moderate strength with partial covalence. Analyses on electron localisation functions, electron density deformations, BCP properties (?G/V and G/ρ) and natural resonance theory demonstrate an increased covalence down the periodic table. 相似文献
16.
Paul Sorensen 《The European Physical Journal C - Particles and Fields》2009,61(4):829-833
Recent data from heavy ion collisions at RHIC show strong near-side correlations extending over several units of rapidity.
This ridge-like correlation exhibits an abrupt onset with collision centrality. In this talk, I argue that the centrality
and beam-energy dependence of these near-angle correlations could provide access to information about the Quark Gluon Plasma
phase boundary and the Equation of State of nuclear matter. A beam-energy-scan at RHIC will better reveal the true source
of these correlations and should be a high priority at RHIC. 相似文献
17.
M. Hauer V. V. Begun M. I. Gorenstein 《The European Physical Journal C - Particles and Fields》2008,58(1):83-110
The aim of this paper is to introduce a new technique for the calculation of observables, in particular multiplicity distributions,
in various statistical ensembles at finite volume. The method is based on Fourier analysis of the grand canonical partition
function. A Taylor expansion of the generating function is used to separate contributions to the partition function in their
power in volume. We employ Laplace’s asymptotic expansion to show that any equilibrium distribution of multiplicity, charge,
energy, etc. tends to a multivariate normal distribution in the thermodynamic limit. A Gram–Charlier expansion additionally
allows for the calculation of finite volume corrections. Analytical formulas are presented for the inclusion of resonance
decay and finite acceptance effects directly into the partition function of the system. This paper consolidates and extends
previously published results of the current investigation into the properties of statistical ensembles. 相似文献
18.
S. Barzilai N. Argaman N. Froumin D. Fuks N. Frage 《Applied Physics A: Materials Science & Processing》2008,93(2):379-385
CaF2 is a thermodynamically stable, non-reactive compound, displaying a relatively high contact angle with pure liquid metal melts.
A remarkable decrease of this contact angle takes place when small amounts of Ti are added to liquid In (a decrease from 125
to 20°) or to liquid Ga (from 118 to 60°). Thermodynamic analysis indicates that this feature cannot be attributed to chemical
reactions between the substrate and the melt. It was suggested that the reason for this behavior may be a preferential titanium
adsorption from the liquid In–Ti or Ga–Ti solution at the substrate surface.
In order to understand the nature of the In–Ti or Ga–Ti bonding in the vicinity of the CaF2 surface, the adsorption energy of 0.5 monolayer of In and Ga was computed for three different surface conditions: (i) clean
CaF2(111), (ii) CaF2(111) with In or Ga adatoms, and (iii) CaF2(111) with Ti adatoms. The differences in adsorption energies for these configurations are related to the electron charge
redistribution in the vicinity of the interface, and to the density of states of the electronic subsystems. It was found that
the adsorption energy of In or Ga increases due to the lateral interactions with the adatoms. According to the analysis, a
strong lateral interaction exists between Ti adatoms and Me, while relatively weak interaction exists between Me and Me adatoms.
The difference of the lateral interactions was considered in order to explain the improvement of the wetting of CaF2 substrate by Ti alloying of In and Ga. 相似文献
19.
Jie Yu Heqing Yang Ruyu Shi Lihui Zhang Hua Zhao Xuewen Wang 《Applied Physics A: Materials Science & Processing》2010,100(2):493-499
GeO2 nanowire arrays have been fabricated by thermal evaporation of Ge powder in air via a vapor–liquid–solid mechanism with Au
as a catalyst. The GeO2 nanowires are single crystalline with a hexagonal structure and have a controllable aspect ratio in the range of 23–167.
The controllable synthesis of GeO2 nanowire arrays with different aspect ratios was achieved by adjusting the heating temperature and time. Photoluminescence
spectra of the GeO2 nanowire arrays were measured at room temperature, and two ultraviolet emission peaks at 347 and 364 nm are observed for
the first time, which indicates that the GeO2 nanowire arrays may have potential applications in nanoscale photonic and electronic devices. Moreover, this vapor–liquid–solid
growth process may be employed for synthesis of the highly oriented nanowire arrays of other oxides, and provides opportunities
for both fundamental research and technological applications. 相似文献
20.
Salim Al-Harthi Mubarak Al-Saadi Imad Al-Omari Husein Sitepu Khalid Melghit Issa Al-Amri Ashraf T. Al-Hinai Senoy Thomas 《Applied Physics A: Materials Science & Processing》2010,99(1):237-244
We report on the analysis of morphology and electronic structure of Fe3+-doped Zn–TiO2 nanoparticles. Crystalline nature, phase, and preferred growth direction of the nanoparticles were all determined. Due to
size effects and OH−–(TiO4)
n
complexes, variation in the energy gap with metallic and semiconducting characters on the same sample was found. The variation
in the energy gap decreased, and the bang gap decayed exponentially with Fe doping and independent of the supporting substrates.
Simultaneous effect of the OH− ligands on the electronic structure and the formation mechanism of nanorods and nanosheets as manifested by the rutile TiO6 octahedra units edge- and corner-shared bonding was discussed. 相似文献