共查询到20条相似文献,搜索用时 31 毫秒
1.
Zh. D. Chaplanova Yu. K. Mikhailovskii V. E. Agabekov V. K. Ol’khovik D. A. Vasilevskii N. A. Galinovskii G. K. Zhavnerko 《Journal of Applied Spectroscopy》2009,76(4):592-598
We have studied the characteristic features of the luminescence of thin films, formed by deposition from solutions and thermal
vacuum deposition (TVD), of 4,4′-bis[(E)-1-(1,3-benzoxazol-2-yl)-2-ethenyl]-2-fluorobiphenyl (BPh-1) and 4,4′-bis[(E)-1-(1,3-benzoxazol-2-yl)-2-ethenyl]-2,2′-difluorobiphenyl
(BPh-2). We have established that fluorine atoms in the biphenyl moiety of the benzoxasole derivatives significantly improve
the stability of the TVD films relative to oxidative aging compared with hexyloxy substituents. Irradiation with UV light
stimulates quenching of luminescence and structuring of the TVD film of the difluoro-substituted derivative. 相似文献
2.
By the method of IR spectroscopy, Raman spectroscopy, and nonempirical (basis 3-21G//3-21G(d,p)) and semiempirical (approximations
AM1 and PM3) quantum-mechanical methods the tautomeric structure of a series of 3-acetyltetramic acid derivatives has been
investigated. It is shown that all the investigated compounds exist in vapor, in solution, and in the crystalline state mainly
in the form of exo-enols among which the prevalent form is that in which lactam carbonyl participates in intrachelate hydrogen
bonding. Complete series of relative stabilities of possible tautomeric forms of the investigated compounds have been established.
General conlusions on the structure of 5-membered ring β,β′-triketones have been formulated.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 154–161, March–April, 2000. 相似文献
3.
Steady-State and Time Resolved Fluorescence Analysis on Tyrosine–Histidine Model Compounds 总被引:1,自引:1,他引:0
Four model compounds, for a tyrosine–histidine covalent bonding, 2-(5-imidazolyl)-4-methylphenol (C–C bonding in ortho-position at the phenyl group); 2′-(1-imidazolyl)-4-methylphenol (C–N bonding in ortho′-position at the phenyl group); 2-(5-imidazolyl)-4-H-phenol and 2-(5-imidazolyl)-4-H-phenol, at physiological pH have been
studied by UV-Vis absorption, steady-state and time resolved fluorescence spectroscopy. Their absorption and emission properties
are presented and discussed. The photophysical properties depend on the para-substituted phenyl group as well as on C–C/C–N bonding in the Phenol–Imidazole linkage. The N position, N1–N3/N1–N4, in the imidazole group was found to be relevant. The results are discussed with relevance to the redox processes of tyrosine
and to better understand the role of a tyrosine–histidine covalent linkage as found in cytochrome c oxidase. 相似文献
4.
N. A. Davidenko I. I. Davidenko A. N. Popenaka I. A. Savchenko A. N. Shumelyuk 《Journal of Applied Spectroscopy》2007,74(6):926-928
We have studied the possibility of recording holograms in films of the 4-methacroyloxy-(4′-carboxy-3′-hydroxy)-2-chloroazobenzene
polycomplex with cobalt, with parallel and orthogonal orientation of the light beam polarization. We have shown that these
films can be used as recording media for polarization holography. The characteristic features of relaxation of the diffraction
efficiency of the holograms are connected with cistrans isomerization of the azobenzene groups and the characteristic features
of structural rearrangement in the polymer matrix. We hypothesize that the information-related characteristics of the studied
recording media can be controlled by external electric or magnetic fields, due to the presence of magnetic metal ions within
the polymer film.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 830–832, November–December, 2007. 相似文献
5.
L. M. Babkov I. I. Gnatyuk G. A. Puchkovskay S. V. Trukhachev 《Journal of Applied Spectroscopy》2009,76(3):303-311
IR spectra of 4-butyl-4′-cyanobiphenyl in the liquid and solid-crystal states were measured in the 400–4000 cm–1 region at 28–70°C. Changes of the spectra as a function of temperature are due to the conformational fluxionality of the
molecules according to calculated IR spectra of the possible 4-butyl-4′-cyanobiphenyl conformers. Calculations were carried
out using the method of fragments and the LEV-100 program package. Bands sensitive to the conformational changes in the molecular
structure were found. IR spectra have been interpreted. Conclusions have been made about the conformations of the sample in
the solid-crystal and liquid phases.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 325–333, May–June, 2009. 相似文献
6.
The efforts of Roy-Sridhar-Close-Cho-Wise-Trivedi to resolve the CDFψ′ anomaly with cascades from above-thresholdχ′
c
states require well defined signatures [a small total width and a large branching fraction forχ′
cJ
→γ+ψ′] for the solution to be viable. Here we estimate the production of such states from BR(B→χ′
cJ
+X)BR(χ′
cJ
→γψ′) andγγ production ofχ′
c2 at CLEO II, and comment on the feasibility of testing the hypothesis in terms of current experimental capabilities. 相似文献
7.
X. M. Song Z. G. Huang H. Q. Lu Q. Q. Sun 《International Journal of Theoretical Physics》2008,47(4):865-872
In dilatonic cosmology model, we study the behavior of attractor solution in ω–ω′ plane, which is defined by the equation of state parameter for the dark energy and its derivative with respect to N (the logarithm of the scale factor a). This is a good method which is useful to the study of classifying the dynamical dark energy models including “freezing”
and “thawing” model. We find that our model belongs to “freezing” type model classified in ω–ω′ plane. We show mathematically the property of attractor solutions which correspond to ω
σ
=−1, Ω
σ
=1. The present values of energy density parameter
,
and
are 0.715001, 0.284972 and 0.00002706 respectively, which meet the current observations well. Finally, we can obtain that
the coupling between dilaton and matter affects the evolutive process of the Universe, but not the fate of the Universe. 相似文献
8.
D. Lehmann 《The European Physical Journal A - Hadrons and Nuclei》1999,4(4):327-328
In an effective theory containing only quark degrees of freedom, such as the extended Nambu–Jona–Lasinio model, the influence
of the axial anomaly can be incorporated by a self-interaction of the 't Hooft determinant type. I will show that despite
the threshold problem related to the η′ meson this leads to a significant suppression of the η′ coupling g
η′qˉq to dynamical quarks which suggests a suppression of the η′NN vertex as compared to the ηNN vertex.
Received: 8 January 1999 相似文献
9.
D. V. Berdyshev V. P. Glazunov A. Ya. Yakubovskaya T. Yu. Kochergina V. F. Anufriev 《Journal of Applied Spectroscopy》2006,73(6):798-806
We have used B3LYP/6-31(d) density functional theory to calculate the frequencies and modes of the normal vibrations of 2-oxo-2,3-dihydro-and
2-methoxy-1,4-naphthoquinones. Based on these calculations within an additive model, we have assigned the carbonyl bands in
the IR spectra of 2,3-dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinones (diquinones 1–4). We have carried out a direct calculation of the vibrational spectra for diquinones 1–4 using PBE and B3LYP correlation functionals. We have shown that the calculation of the vibrational spectra of the diquinones
based on an additive model on the whole is quite consistent with the results of direct calculations and the experimental spectra.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 713–720, November–December, 2006. 相似文献
10.
The electric conduction and photoconduction of sandwich-type poly-N-epoxypropylcarbazole (PEPC) and 3,6-di-Br-poly-N-epoxypropylcarbazole
(3,6-di-Br-PEPC) films containing 33 wt.% of the dye 1,8-naphthoylene-1′, 2′-benzimidazole (NBI) have been investigated. It
has been established that the PEPC films, as compared to the 3,6-di-Br-PEPC films, have a higher electric conduction and a
lower photosensitivity and an electric field exerts a stronger quenching effect on the photoluminescence of the first-mentioned
films. Analysis of the voltampere and lux-ampere characteristics and the kinetics of electric conduction of these films has
shown that the space charge and recombination via dye molecules in them influence their electric conduction and photoconduction.
The volume recombination of charges is radiative in character.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 5, pp. 627–631, September–October, 2005. 相似文献
11.
A new solid substrate-room temperature phosphorescence (SS-RTP) method for the determination of trace manganese (II) has been
established. It bases on the fact that fullerol (R) emits strong and stable room temperature phosphorescence (RTP) on filter
paper substrate. H2O2 can oxidize R to cause the SS-RTP quenching. But manganese (II) can obstruct H2O2 to oxidize R, and enhance the RTP of R. α,α′-Bipyridine (Bipy) can sensitize the RTP. After adding Bipy, the ΔI
p enhances 7 times than that without Bipy. Under the optimum conditions, the linear dynamic range of this method is 0.016–1.12 pg spot−1 with a detection limit (L.D.) of 4.6 fg spot−1 ( is the absolute mass of Mn2+), and the regression equation of working curve is ΔI
p=25.20 + 63.55 (pg spot−1), n=6, r=0.9983. For 0.016 and 1.12 pg spot−1 Mn2+, RSDS are 4.3 and 4.8%, respectively (n=7). This method has been applied to the determination of trace manganese (II) in actual sample with high sensitivity and
good selection. And the reaction mechanism of SS-RTP is discussed. 相似文献
12.
Sayan K. Chakrabarti 《General Relativity and Gravitation》2007,39(5):567-582
We obtain the quasinormal modes for tensor perturbations of Gauss–Bonnet (GB) black holes in d = 5, 7, 8 dimensions and vector perturbations in d = 5, 6, 7 and 8 dimensions using third order WKB formalism. The tensor perturbation for black holes in d = 6 is not considered because of the fact that the black hole is unstable to tensor mode perturbations. In the case of uncharged
GB black hole, for both tensor and vector perturbations, the real part of the QN frequency increases as the Gauss–Bonnet coupling
(α′) increases. The imaginary part first decreases upto a certain value of α′ and then increases with α′ for both tensor and vector perturbations. For larger values of α′, the QN frequencies for vector perturbation differs slightly from the QN frequencies for tensorial one. It has also been
shown that as α′ → 0, the quasinormal frequencies for tensor and vector perturbations of the Schwarzschild black hole can be obtained. We
have also calculated the quasinormal spectrum of the charged GB black hole for tensor perturbations. Here we have found that
the real oscillation frequency increases, while the imaginary part of the frequency falls with the increase of the charge.
We also show that the quasinormal frequencies for scalar field perturbations and the tensor gravitational perturbations do
not match as was claimed in the literature. The difference in the result increases if we increase the GB coupling. 相似文献
13.
RN Mohapatra 《Pramana》2000,55(1-2):289-296
It is shown that if the supersymmetric Standard Model (MSSM) emerges as the low energy limit of a high scale left-right symmetric
gauge structure, the number of uncontrollable CP violating phases of MSSM are drastically reduced. In particular it guarantees
the vanishing of the dangerous phases that were at the root of the so called SUSY CP problem. Such a symmetric gauge structure
is independently motivated by the smallness of neutrino masses that arise via seesaw mechanism automatic in the theory. The
minimal version of this theory also provides an explanation of the smallness of ε′/ε as a consequence of the high scale parity
invariance.
This talk is based on work done in collaboration with K S Babu and B Dutta. 相似文献
14.
Using the IR spectroscopy method, it has been established that formation of a monolayer 1-(β-oxyethyl)-3-methyl-5-nitroimidazole
(metronidazole) on the surface of nonporous amorphous highly dispersed silica (Ssp = 230 m2/g) occurs during its absorption in an amount of 0.6 mmole/g. Such a content of adsorbate corresponds to the concentration
of free silanol groups that are main active centers of the surface. Based on the analysis of the IR spectra of the specimens
obtained and the dependence of the degree of perturbation of silanol groups on the content of adsorbed metronidazole, the
structure of the surface adsorption complexes is suggested.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 717–721, November–December, 2005. 相似文献
15.
A. V. Mudryi A. V. Ivanyukovich M. V. Yakushev V. S. Kulikauskas V. S. Chernysh 《Journal of Applied Spectroscopy》2006,73(6):928-931
We have used low-temperature (4.2–78 K) photoluminescence to study defect formation processes in Cu(In,Ga)Se2 films when bombarded by protons with energy 380 keV. We have observed formation of luminescence centers with deep levels
at ∼410 meV and 470 meV.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 828–830, November–December, 2006. 相似文献
16.
A fluorescent assay of Hg2+ in neutral aqueous solution was developed using N-[p-(dimethylamino)benzamido]-N′-phenylthiourea (1). 1’s fluorogenic chemodosimetric behaviors towards various metal ions were studied and a high sensitivity
as well as selectivity was achieved for Hg2+. It was because of a strongly fluorescent 1,3,4-oxadiazoles which was produced by the Hg2+ promoted desulfurization reaction. The spectra of ESI mass and IR provided evidences for this reaction. According to fluorescence
titration, a good linear relationship ranging from 1.0 × 10−7 to 2.0 × 10−5 mol l−1 was obtained with the limit of detection as 3.1 × 10−8 mol l−1.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
We have used the PBE/3z, B3LYP/6-31G, B3LYP/6-31G(d), and B3LYP/6-311G(d) methods to study the conformational mobility of
2,3-dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinones (1–4). We have shown that more than 99% of these compounds exist as the major tautomeric form, while differences in the structure
of the Q2H (2,3-dihydro-2-oxo-1,4-naphthoquinones) and Q1,4 (1,4-naphthoquinon-2-yl) moieties lead to qualitative differences in the internal rotation potentials of the ethyl substituents
V(θEt−1) and V(θEt−2), and consequently each of compounds 1−4 exists as six different rotameric forms. For diquinone 3, we have calculated the dependences of the frequencies (ν) and intensities (A) of the normal vibrations on the torsional
angles θEt−1 and θEt−2, and also on the changes in the geometry of the ether bond. We have found that the values of ν and A for the bands in the
carbonyl region of the IR spectrum change little on going from one rotameric form to another, and also for the in-plane bends
of the ether bond, and change considerably for the out-of-plane bends of the ether bond. However, for T ≤ 300 K, there is
no qualitative change in the overall contour, and it can be interpreted based on a simple additive model.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 573–581, September–October, 2006. 相似文献
18.
B. I. Turko V. B. Kapustyanyk V. P. Rudyk M. V. Partika M. V. Kvasnytsya A. P. Vas’kiv 《Journal of Applied Spectroscopy》2007,74(2):310-312
We have studied the behavior of the intrinsic absorption edge in zinc oxide thin films in the temperature range 80–300 K.
We have observed that the intrinsic absorption edge in films with crystal sizes of ≈45 nm or larger is described by the empirical
Urbach’s rule, while in films with crystallite sizes of ≈15 nm, it is described by a modified Urbach’s rule. We have calculated
the effective frequency of phonons taking part in formation of the absorption edge.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 275–277, March–April, 2007. 相似文献
19.
The fluorescence excitation spectra and polarization of the fluorescence of a bichromophore cooled in a supersonic jet are
measured. The bichromophore consists of 2,5-diphenyloxazole (PPO) and 1-(5′-phenyl-1′, 3′-oxazole-2′-yl)-4-(5′-phenyl-1′,3′,4′-oxadiazole-2′-yl)-benzene
(POPDP) connected by the methylene bridge -(CH2)-. Based on the analysis of these components and theoretical calculations, it has been proven that the total intramolecular
singlet-singlet transfer of the energy of electronic excitation from the energy donor PPO to the acceptor POPDP occurs in
a time of 10−12 sec.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 460–463, July–August, 2005. 相似文献
20.
Rhodamine B (Rh-B) has been embedded in PolyAcrylic acid (PAA) films. The materials are studied for the laser action with
nitrogen laser excitation. The lasing efficiency of Rh-B/PAA films is comparable to that of rhodamine 6G in methanol. There
is a 50% reduction in the laser intensity of the films with 2600 pulses from the N2 laser (2 Hz). The photostability of these materials is far superior to that of other polymeric materials and is comparable
to that of sol–gel materials.
Received: 22 May 1996 /Revised version: 10 July 1996 相似文献