共查询到20条相似文献,搜索用时 31 毫秒
1.
L. K. Neudachina E. V. Dedyukhina O. V. Evdokimova N. V. Pechishcheva E. V. Osintseva K. Yu. Shunyaev 《Journal of Applied Spectroscopy》2010,77(2):206-212
The fluorescence properties of N,N-di(2-carboxyethyl)-p-anisidine (I) in solvents of various nature and in the crystalline state have been studied at room temperature (273 K) and at the boiling
point of liquid nitrogen (77 K). Fluorescence in aqueous solutions of I with protonated (λ
ex
/λ
fl
max
= 225/290 nm) and unprotonated (λ
ex
/λ
fl
max
= 270/380 nm) amino nitrogen has been detected. On going from aqueous solutions to nonaqueous, the fluorescence band of unprotonated
I experiences a blue shift and its intensity rises. The fluorescence intensity of the band in aprotic polar solvents is higher
than that in protic solvents. A linear dependence of the fluorescence intensity of deprotonated I on Cu(II) concentration (ranging from 1.0 to 5.0 mg/dm3) in aqueous solution has been found. The fluorescence intensity of I in aqueous solutions at 77 K and pH 1–6 has been shown to increase in the presence of Zn(II) (1–170 mg/dm3) and Cd(II) (2–330 mg/dm3) although a similar dependence is not observed at 293 K. 相似文献
2.
The optical absorption behavior of Tl+ doped Rb(Br1–x
I
x
) mixed crystals (with x = 0.00, 0.05, and 0.10) grown under vacuum by slow cooling from the melt has been studied. Absorption spectra of the mixed
crystals recorded at room temperature showed that the characteristic A-absorption band of Tl+ ions in the Rb(Br1–x
I
x
) system (0.1 mol. %) with x = 0.00 (i.e., RbBr:Tl+) broadened with the iodine content towards the low energy side. Changes in the absorption spectra of the mixed crystals are
due to creation of some complex centers involving Tl+, Br–, and I- ions with energy levels inside the band gap while forming the mixed crystal. The absorption spectra of gamma-irradiated mixed
crystals showed the F-band, which shifted towards the low energy side due to the existence of iodine ions in the mixed crystals. 相似文献
3.
International comparisons of I2 stabilized ion lasers operated at 514.5 nm have shown a laser frequency reproducibility of 2·10−10
v to 5·10−12
v. These results encouraged the international acceptance of the wavelength value λvac=514.673467 for thea
3 hyperfine component of the127I2 line 43-0P(13). 相似文献
4.
Swapna Ray Jain 《International Journal of Theoretical Physics》1996,35(5):903-909
Conserved quantities and the multi-Hamiltonian structure for the integrable coupled kdv system which is associated with the
isospectral flow [(∑
i=0
N−1
ε
i
λ
i
)∂2 + ∑
i=0
N−l
V
1λ
i
]φ=λ
N
φ are deduced by the Drienfeld-Sokolov formalism. 相似文献
5.
A. A. Zhukov M. R. Trunin A. T. Sokolov N. N. Kolesnikov 《Journal of Experimental and Theoretical Physics》1997,85(6):1211-1217
The real part R
s and the imaginary part X
s of the surface impedance Z
s=R
s+ iX
s of Tl2Ba2CaCu2O8−δ
and YBa2Cu3O6.95 single crystals have been measured with high precision at frequency ω/2π=9.4 GHz in the temperature range 0<T<140 K. In the Tl2Ba2CaCu2O8−δ
crystal a linear temperature dependence R
s(T) has been found for T⩽50 K, and the magnetic field penetration depth λ(4.2 K)=X
s(4.2 K)/ω μ
0≈3760 Å has been measured. Along with well known features of the function Z
s(T) in high-quality YBa2Cu3O6.95 single crystals, such as the linearity of λ(T) and R
s(T) for T<T
c/3 and a maximum of R
s(T) at T∼T
c/2, the linearity range of λ(T) extends to T≃50 K, and this curve has a plateau in the range 60<T<85 K. The curve of R
s(T) in both the superconducting and normal states of YBa2Cu3O6.95 is well described by a two-fluid model with the electron-phonon mechanism of quasiparticle relaxation. A formula describing
the curve of λ
2(0)/λ
2(T) throughout the studied temperature range is also given.
Zh. éksp. Teor. Fiz. 112, 2210–2222 (December 1997) 相似文献
6.
M. Bryushinin V. Golubev Y. Kumzerov D. Kurdyukov I. Sokolov 《Applied physics. B, Lasers and optics》2009,95(3):489-495
We report an experimental investigation of the non-steady-state photoelectromotive force in nanostructured GaN within porous
glass and polypyrrole within chrysotile asbestos. The samples are illuminated by an oscillating interference pattern created
by two coherent light beams and the alternating current is detected as a response of the material. Dependences of the signal
amplitude versus temporal and spatial frequencies, light intensity, and temperature are studied for two wavelengths λ=442 and 532 nm. The conductivity of the GaN composite is measured: σ=(1.1–1.6)×10−10 Ω−1 cm−1 (λ=442 nm, I
0=0.045–0.19 W/cm2, T=293 K) and σ=(3.5–4.6)×10−10 Ω−1 cm−1 (λ=532 nm, I
0=2.3 W/cm2, T=249–388 K). The diffusion length of photocarriers in polypyrrole nanowires is also estimated: L
D=0.18 μm. 相似文献
7.
Lichang Yin Yunzuo Liu Jingbin Lu Guangyi Zhao Xianfeng Li Xiaoguang Wu Guangsheng Li Shuxian Wen Chunxiang Yang 《The European Physical Journal A - Hadrons and Nuclei》2001,11(4):379-383
High-spin states of 160Lu have been studied through the 144Sm( 19F, 3n) reaction. The previously known πh
11/2⊗υi
13/2 yrast band is extended from I
π = 21- to 25- and a four quasiparticle band with configuration πh
11/2[523]7/2 -⊗υh
9/2[521]3/2 -⊗ (υi
13/2)2 is reported.
Received: 21 May 2001 / Accepted: 19 July 2001 相似文献
8.
M. V. Bogatyrenko S. I. Bredikhin 《Journal of Experimental and Theoretical Physics》1997,85(2):381-385
A new effect of illumination on ionic conductivity and activation energy of migration of mobile Ag+ cations in RbAg4I5 superionic crystals has been detected and studied. Reversible changes in the ionic conductivity due to illumination of superionic
crystals are caused by reversible changes in the structure of electronic centers caused by elastic strain around these centers.
The effect of elastic deformation on the process of ionic transport and activation energy for diffusion of mobile silver cations
has been studied. Photostimulated recovery of the ionic conductivity after its change due to preliminary illumination of a
RbAg4I5 superionic crystal with light of wavelength λ≃430 nm has been detected. This recovery of the ionic conductivity is due to excitation of centers in complexes generated
by previous illumination of tested samples.
Zh. éksp. Teor. Fiz. 112, 698–706 (August 1997) 相似文献
9.
The energy spectra of traps in NaCl crystals have been studied in detail by the method of thermoluminescence. Crystals of
NaCl were undoped but treated thermally in different ways. The activation energies of traps form a single oscillator series,
E
n
=ℏω
TL
(n+1/2), ℏω
TL
=903 cm-1. Contrary to other previously studied crystals with complex lattices, the corresponding line ℏω
Ram
=ℏω
TL
was not found in Raman spectra of NaCl. It is assumed that the oscillator rule is governed by the polaron nature of traps.
The trap activation energy is determined by the vibration level from which the transition of the charge carrier to the excited
luminescence centre is made possible and depends on the distance between these centres. 相似文献
10.
Suleyman Cabuk 《Central European Journal of Physics》2012,10(1):239-252
The nonlinear optical properties of some ABO3 materials (BaTiO3, KNbO3, LiTaO3 and LiNbO3) are studied by density functional theory (DFT) in the local density approximation (LDA) expressions based on first-principle
calculations. Our goals are to give the details of the calculations for linear and nonlinear optical properties, including
the linear electro-optic (EO) tensor for some ABO3 structures with oxygen octahedral structures using first-principles methods. These results can then be used in the study
of the physics of ferroelectrics, specifically, we present calculations of the second harmonic generation response coefficient
X
ijk
(2) (−2ω, ω, ω) over a large frequency range for ABO3 crystals. The electronic linear EO susceptibility X
ijk
(2) (−ω, ω,0) is also evaluated below the band gap. These results are based on a series of the LDA calculations using DFT. Results for
X
ijk
(2) (−ω, ω,0) are in agreement with experiments below the band gap. The results are compared with the theoretical calculations and the
available experimental data. 相似文献
11.
S. Bredikhin 《Ionics》2000,6(1-2):78-85
The phenomena of the reversible transformation of concentration and a structure of luminescence centers and of the concentration
of mobile silver ions in local irradiated region of RbAg4I5 superionic crystals are studied. A new effect of illumination on ionic conductivity and activation energy of migration of
mobile Ag+ cations in RbAg4I5 superionic crystals are observed. Reversible changes in the ionic conductivity due to illumination of superionic crystals
are caused by reversible change in the structure of electronic centers caused by elastic strain around these centers. The
effect of elastic deformation on the process of ionic transport and activation energy for diffusion of mobile silver cations
are studied. Photostimulated recovery of the ionic conductivity after its change due to preliminary illumination of a RbAg4I5 superionic crystal with light of wavelength λ=430 nm are detected. This recovery of the ionic conductivity is due to excitation
of centers in complexes generated by previous illumination of tested samples. 相似文献
12.
The molecular dynamics (MD) simulation, based on a realistic atom-atom interaction potential, was performed on 4-n-pentyl-4'-cyanobiphenyl (5CB) in the nematic phase. The rotational viscosity coefficients (RVCs) γ
i, (i = 1, 2) and the ratio of the RVCs λ = - γ
2/γ
1 were investigated. Furthermore, static and frequency-dependent dielectric constants and ε were calculated using parameters obtained from the MD simulation. Time correlation functions were computed and used to determine
the rotational diffusion coefficient, D
⊥. The RVCs and λ were evaluated using the existing statistical-mechanical approach (SMA), based on a rotational diffusion
model. The SMA rests on a model in which it is assumed that the reorientation of an individual molecule is a stochastic Brownian
motion in a certain potential of mean torque. According to the SMA, γ
i are dependent on the orientational order and rotational diffusion coefficients. The former was characterized using: i) orientational
distribution function (ODF), and ii) a set of order parameters, both derived from analyses of the MD trajectory. A reasonable
agreement between the calculated and experimental values of γ
i and λ was obtained.
Received 22 March 2000 and Received in final form 8 October 2000 相似文献
13.
A. Apolonskii S. Baluschev U. Hinze E. Tiemann B. Wellegehausen 《Applied physics. B, Lasers and optics》1997,64(4):435-442
In a double-Λ level configuration of Na2 molecules, involving rotational–vibrational levels of the X, A and B bands, continuous resonant frequency mixing ω4=ω1−ω2+ω3 is demonstrated. A DCM dye laser at 661 nm (λ1) pumps a molecular Raman laser at 746 nm (λ2) in a sodium heatpipe, which is used to generate the molecular vapour. In the same heatpipe, both fields are mixed with the
radiation of an argon-ion laser at 514 nm (λ3) to generate up-converted laser radiation at 473 nm (λ4). For laser powers of 200 mW (λ1), 700 mW (λ2, internal power) and 140 mW (λ3), an output power of 120 μW (λ4) has been achieved. Dependences of the generated radiation on the pump fields (powers and detunings) and polarization features
are presented; influences of coherent coupling and population transfer mechanisms are discussed.
Received: 7 October 1996 相似文献
14.
The subject of investigation is the kinetic mechanisms intensifying chain reactions that proceed in a hydrogen-air mixture
when O2 molecules dissociate under the action of laser radiation with wavelength λ
I
= 193.3 nm and are excited into the b
1Σ
g
+ electron state by radiation with λ
I
= 762.346 nm. The efficiencies of both methods to initiate ignition are compared. Numerical simulation shows that the ignition
temperature for the laser-induced excitation of O2 molecules into theb
1Σ
g
+ state is lower than for the dissociation of O2 molecules by UV laser radiation, with the energy supplied to the mixture being the same. However, both photochemical methods
are much more efficient than mere heating of the mixture by laser radiation or another source of heat. 相似文献
15.
G. V. Mayer T. N. Kopylova Yu. M. Andreev V. A. Svetlichnyi E. N. Tel’minov 《Russian Physics Journal》2009,52(6):640-645
The possibility of parametrical conversion of visible radiation of solid-state organic lasers into the middle-IR range of
the spectrum in nonlinear GaSe1–x
S
x
(x = 0‒0.13) crystals is investigated. Generation at the difference frequency (wavelength λ3 = 9.43 μm) of induced oxazine-1 (at λ1 = 740 nm) and rhodamine-800 (λ2 = 803.4 nm) radiation is excited. The conversion efficiency is estimated, and prospects for its further increase are demonstrated. 相似文献
16.
M. Ya. Amus’ya A. I. Mikhailov I. A. Mikhailov 《Journal of Experimental and Theoretical Physics》1998,86(2):299-304
Inelastic photon scattering by helium atoms and helium-like ions with simultaneous excitation of the two-electron transition
1s
2→2s
2 is examined in the nonrelativistic energy range I≪ω≪m (I is the ionization potential, ω is the photon energy, m is the electron mass, and ℏ=c=1). The electrons are assumed to be moving in the Coulomb field of the nucleus, and the electron-electron interaction is
taken into account in the lowest perturbation order. The differential and total cross sections of the process and the autoionization
width of the 2s
2 energy level are calculated. The numerical value of the autoionization width is found to agree with the results of the more
rigorous calculations of other researchers.
Zh. éksp. Teor. Fiz. 113, 539–549 (February 1998) 相似文献
17.
FePS3 is a layered antiferromagnet (T
N=123 K) with a marked Ising anisotropy in magnetic properties. The anisotropy arises from the combined effect of the trigonal
distortion from octahedral symmetry and spin-orbit coupling on the orbitally degenerate5
T
2g
ground state of the Fe2+ ion. The anisotropic paramagnetic susceptibilities are interpreted in terms of the zero field Hamiltonian, ℋ=Σi [δ(L
iz
2
−2)+|λ|L
i
.S
i
]−Σ
ij
J
ij
S
i
.S
j
. The crystal field trigonal distortion parameter Δ, the spin-orbit coupling λ and the isotropic Heisenberg exchange,J
ij, were evaluated from an analysis of the high temperature paramagnetic susceptibility data using the Correlated Effective
Field (CEF) theory for many-body magnetism developed by Lines. Good agreement with experiment were obtained for Δ/k=215.5 K; λ/k=166.5 K;J
nn
k=27.7 K; andJ
nnn
k=−2.3 K. Using these values of the crystal field and exchange parameters the CEF predicts aT
N=122 K for FePS3, which is remarkably close to the observed value of theT
N. The accuracy of the CEF approximation was also ascertained by comparing the calculated susceptibilities in the CEF with
the experimental susceptibility for the isotropic Heisenberg layered antiferromagnet MnPS3, for which the high temperature series expansion susceptibility is available. 相似文献
18.
Ó. Martínez-Matos G.A. Torchia A. Lencina J.O. Tocho 《Applied physics. B, Lasers and optics》2008,91(2):363-367
Volume grating formation by spatially-selective defect bleaching is demonstrated in coloured KCl:CO3K2 crystals. The sample is coloured by a train of pulses with a wavelength of λ= 266 nm and bleached with a cw Ar-laser with
a wavelength of λ= 514.5 nm. Diffraction efficiency for a 1.6 μm grating period is studied both experimentally and theoretically,
using the evolution of colour centre concentration. Hologram recording parameters are obtained and the evolution of the spatial
grating profile is discussed. Diffraction efficiencies three times higher than previously published efficiencies are obtained.
PACS 42.40.Ht; 42.40.Lx; 42.70.Ln 相似文献
19.
For operators with a discrete spectrum, {λ
j
2}, the counting function of λ
j
's, N (λ), trivially satisfies N ( λ+δ ) −N ( λ−δ ) =∑
j
δλ
j
((λ−δ,λ+δ]). In scattering situations the natural analogue of the discrete spectrum is given by resonances, λ
j
∈ℂ+, and of N (λ), by the scattering phase, s(λ). The relation between the two is now non-trivial and we prove that
where ωℂ+ is the harmonic measure of the upper of half plane and δ can be taken dependent on λ. This provides a precise high energy
version of the Breit–Wigner approximation, and relates the properties of s (λ) to the distribution of resonances close to the real axis.
Received: 16 October 1998 / Accepted: 28 January 1999 相似文献
20.
Doping of ZnS crystals with background impurities and ZnS:Al crystals by various concentrations of copper from a bismuth melt
has been carried out. The photoluminescence spectra of the starting ZnS crystals annealed in the bismuth melt and doped by
copper have been investigated. Interpretation of the experimental results according to the model in which the associates (Cu
Zn
′
Cu
i
●
) are responsible for the B-Cu band (≈460 nm) and the donor—receptor pairs [Cu
i
●
-(Cu
Zn
′
Cu
i
●
)] are responsible for the G-Cu band (≈505 nm) is given. It is assumed that doping by copper from a bismuth melt is accompanied
by the separation of a CuxS-type phase. It has been shown that heat treatment of ZnS crystals in the Bi melt does not lead to the appearance of luminescence
centers based on BiZn, BiS, and Bii.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 794–798, November–December, 2005. 相似文献