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1.
A. V. Mudryi A. V. Ivanyukovich A. V. Korotkii V. V. Emtsev M. V. Yakushev 《Journal of Applied Spectroscopy》2006,73(1):95-98
Using photoluminescence and transmission measurements, we have studied the optical properties of indium nitride powder and
thin films grown by molecular beam epitaxy. The bandgap for InN powder with electron concentration ∼ 4·1019 cm−3 was 0.94 eV, and for InN films with electron concentrations ∼1018 cm−3 it was 0.7 eV. We have established that when the electron concentration is increased to 8·1019 cm−3, the bandgap of InN increases to 1.0 eV. The change in the bandgap as a function of the concentration is due to the appearance
of the Burstein-Moss effect.
Report given at the Fifth Belorussian-Russian Seminar on Semiconductor Lasers and Systems Based on Semiconductor Lasers, June
1–5, 2005, Minsk, Belarus.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 86–89, January–February, 2006. 相似文献
2.
Photoinduced electron transfer (PET) was studied in toluene solutions of the Pd-porphyrin-quinone (Pd-PQ) dyad by flash photolysis
in the picosecond time range and by a luminescence method. It is found that Pd-PQ has a high rate of intercombination conversion
Kisc=(7.7±0.2)·1010 sec−1. Competing intramolecular PET occurs from the lower excited singlet state of the dyad with the rate constant K
et
s
=(2.7 ±0.3)·1010 sec−1. Therefore, ∼74% of excited molecules from the dyad make a transition to the triplet T1 state and 26% take part in intramolecular PET resulting in formation of radical products. The radical products relax to the
ground state with the rate constant K=(7.4±0.2)·109 sec−1.
Institute of Molecular and Atomic Physics of the National Academy of Sciences of Belarus, 70, F. Skorina St., Minsk, 220072,
Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 1, pp. 11–18, January–February, 1999. 相似文献
3.
A computer-aided optoacoustic gas analyzer based on a continuous13C16C2 laser for multicomponent pollution of atmospheric air is described. The analyzer has the ability to detect absorption of
radiation by detected substances at the level of ∼1·10−9 cm−1 at a time resolution of 30 sec. Results of an experiment on simultaneous detection of H2O, CO2, NO2, NH3, HNO3, OCS, and C2H4 in the atmospheric air using 40 laser lines are presented.
B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 345–350, May–June, 1999. 相似文献
4.
We have measured the absorption cross sections of oxygen molecules in oxygen and in an oxygen-argon mixture heated by a shock
wave, in the wavelength range 190–250 nm at temperatures of 1500–7000 K, for thermal equilibrium conditions behind the shock
wave front. Analysis of the absorption cross sections obtained allowed us to select a data set that adequately describes the
absorption characteristics of the electronic transition X3Σ
g
−
→ B3Σ
u
−
for the oxygen molecule.
In order to approximate the temperature dependence of these cross sections at a temperature of 1500–4500 K, we chose the function
σ(λ, T) = σ0(λ)(1 − exp (−θ/T)) exp (− n*θ/T) where θ0 = 1.4·10−17, 1.4·10−17, 1.2·10− 17, and 1.3·10−17 cm2, n* = 3.1, 4.1, 5.6, and 7.47 for wavelengths 190, 210, 230, and 250 nm, respectively; θ = 2240 K is the characteristic temperature
of the O2 molecules. The approximation error was 19–25% and did not exceed the experimental error.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 13–17, January–February, 2006. 相似文献
5.
A highly sensitive H-point standard addition method (HPSAM) was investigated for identification of dopamine and ascorbic acid in some synthetic and pharmaceutical samples in an aqueous medium at pH 9.2 using a universal buffer. The most suitable wavelengths for dopamine and ascorbic acid detection are 260:271 nm and 248:270 nm respectively. Recovery values are between 99.0–101 %. Also, the effect of most common interferents was studied. Detection ranges for dopamine and ascorbic acid are 2·10–6–5·10–5 M and 6·10–6–3·10–5 M respectively with an RSD range between 1.3 and 2.0 %. The method was used to determine both reagents in real and synthesized samples. 相似文献
6.
We study experimentally the frequency dependences of the refractive index n and the absorption coefficient k of distilled,
sea, and river water. The measurements were performed using a quasioptical device with a backward-wave oscillator as the radiation
source and OAP-7 optical-acoustic receivers at a water temperature of 27°C in the cell. The quantities n and k were determined
from the measured transmission and reflection coefficients of the cell with water by means of joint numerical solution of
the equations for these quantities. For distilled water in the frequency range f = 75–120 GHz, we obtained n = 6.142–3.926
· 10–2f[GHz] + 1.307 · 10–4(f[GHz])2 and k = 3.607–2.101 · 10−2 f[GHz] + 5.252 · 10–5(f[GHz])2. On the whole, these data are in good agreement with the measurement results obtained by other authors at several frequencies
of the indicated range and coincide with the calculation data based on the models by Meissner and Wentz and by Liebe et al.
within the limits of the rms determination errors 0.05 and 0.02 for the parameters n and k, respectively. The values of n
and k for different seawater samples and river water containing insoluble admixtures coincide with the values of these quantities
for distilled water within the limits of the experimental measurement errors 3–5% and 1–2%, respectively. The dependences
n(f) and k(f) obtained experimentally for seawater are compared with those calculated on the basis of the developed models.
Measurements of the transmission spectrum of a cell with double distilled water were performed for low power density of radiation
(less than μW/cm2) to reproduce the effect of water resonant transparency reported many times in the literature. Our measurements did not reveal
any resonant features in the spectral behavior of the refractive index n and the absorption coefficient k of water and gave
the same result as for a power density exceeding the threshold of appearance of this effect.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 6, pp. 489–501, June 2006. 相似文献
7.
O. V. Ovchinnikov A. B. Evlev M. A. Efimova V. G. Klyuev A. N. Latyshev A. N. Utekhin A. M. Kholkina 《Journal of Applied Spectroscopy》2005,72(6):809-813
An anti-Stokes luminescence band with λmax = 515 nm of microcrystals of solid AgCl0.95I0.05 solutions excited by a radiation flux of density 1013–1015 quanta/cm2·sec in the range 600–800 nm at 77 K was detected. It is shown that the intensity of this luminescence and the frequency of
its excitation depend on the prior UV-irradiation of samples. Analysis of the stimulated-photoluminescence spectra and the
anti-Stokes luminescence excitation spectra of the indicated microcrystals has shown that to the centers of anti-Stokes luminescence
excitation correspond local levels in the forbidden band of the crystals. These states are apparently due to the atomic and
molecular disperse silver particles that can be inherent in character or formed as a result of a low-temperature photochemical
process.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 738–742, November–December, 2005. 相似文献
8.
I. N. Nichiporovich S. M. Bachilo A. P. Losev G. D. Egorova 《Journal of Applied Spectroscopy》1999,66(6):917-922
It was established that in aqueous solutions of anionic porphyrins the processes of triplet-triplet (T-T) annihilation are
absent (K2<2.5·105 M−1 sec−1), while a delayed annihilation fluorescence can be detected for these porphyrins in methanol (K2≊3.5·107 M−1 sec−1) and for their lipophilic analogs in organic solutions (K
2≊2.5·109 M−1 sec−1), and the kinetics of absorption of the latter porphyrins in triplet states is dependent on the intensity of the exciting
radiation. The extremely small constant of T-T annihilation of anionic porphyrins can be due to the formation of a relatively
dense solvate shell consisting of water molecules around the charged groups of the porphyrin molecules, which increases steric
barriers and thus prevents an exchange-resonance transfer of energy between triplet excited molecules in aqueous solutions.
It is also shown that porphyrin molecules can electrostatically repel one another when in their structure there are charged
groups.
To whom correspondence should be addressed.
Deceased.
Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70 F. Skorina Ave., Minsk, 220072, Belarus;
e-mail: llum@imaph.bas-net.by. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 791–795, November–December,
1999. 相似文献
9.
F. P. Korshunov T. P. Larionova A. V. Mudryi A. I. Patuk I. A. Shakin 《Journal of Applied Spectroscopy》1999,66(3):410-414
Using low-temperature (4.2–78 K) photoluminescence, we study the processes of defect formation in silicon films on sapphire
irradiated with high-energy particles (electrons, γ-quanta of60Co). It is established that carbon atoms, as a residual process impurity, participate in the formation of luminescence centers
stable up to annealing temperatures of about 550 K. For carbon-containing centers we reveal a shift in the spectral lines
relative to their position in spectra of single-crystal silicon. It is proposed that this spectral shift is associated with
the presence of internal stresses of about 5·108 N/m2 in the silicon films.
Institute of Solid-State Physics and Semiconductors, National Academy of Sciences of Belarus, 17, P. Brovka Str., Minsk, 220072,
Belarus. Translated from Zhurnal Prikladnoi Spektroskefii, Vol. 66, No. 3, pp. 383–386, May–June, 1999. 相似文献
10.
V. N. Gorelkin V. G. Grebinnik K. I. Gritsai V. N. Duginov V. A. Zhukov T. N. Mamedov V. G. Ol’shevski V. Yu. Pomyakushin A. V. Stoikov I. L. Chaplygin I. A. Krivosheev B. A. Nikol’skii A. N. Ponomarev 《JETP Letters》1996,63(7):566-571
The residual polarization of negative muons in n-type silicon with impurity density (1.6±0.2) · 1013 cm−3 is investigated as a function of temperature in the range 10–300 K. The measurements are performed in an external magnetic
field of 0.08 T oriented transversely to the spin of the muons. Relaxation of the muon spin and a shift of the precession
frequency are observed at temperatures below 30 K. The relaxation rate at 30 K equals 0.25±0.08 μs−1. The shift of the precession frequency at 20 K equals 7 · 10−3. Both the relaxation rate and the shift of the precession frequency increase as the temperature decreases. At temperatures
below 30 K the relaxation rate is described well by the relation Λ=bT
−q
, where q=2.8±0.2.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 7, 539–543 (10 April 1996) 相似文献
11.
Experimental performance parameters of Hg implanted Hg1−x
Cd
x
Te photovoltaic detectors are analyzed. At 77K, for 8–14 μm band, a comparison is made between performances and theoretical
ultimate diffusion limits in low frequency direct detection. Experimental features are well-explained by a model based on
the Auger band-to-band process for carrier recombination. Peak detectivities exceeding 1011 cm Hz1/2W−1, external quantum efficiencies as high as 90%, and zero-bias resistance-area products better than 1 Ω·cm2 have been achieved in devices with 12 μm cutoff wavelengths. In the 3–5 μm band performances are far from the diffusion limit.
Notwithstanding, at 77K zero-bias resistance-area products are better than 104Ω·cm2 and detectivities of the order of 1012 cm Hz1/2W−1 were observed at 5 μm.
Predominant generation-recombination contribution are present at room temperature in 1–1.3 μm photodiodes whose detectivities,
primarily limited by the Johnson noise, at 1.3 μm are higher than 1011 cm Hz1/2W−1 at 300 K.
The high frequency response of the photodiodes is also discussed. Response times as low as 0.5 ns are reached despite some
limitations arising from the implanted layer sheet resistance.
Work supported by CNR-CISE contract No. 73.01435. 相似文献
12.
I. P. Kozlov V. B. Odzhaev I. A. Karpovich V. N. Popok D. V. Sviridov 《Journal of Applied Spectroscopy》1998,65(3):390-394
Polyethylene and polyamide-6 films implanted with 100 keV B+ ions within the dose range of 1·1014–1·1017 cm−2 are investigated by the methods of optical spectroscopy. It is shown that in the case of ion-implanted polymers, optical
absorption is caused by carbon nanoclusters formed in the tracks of bombardment ions. The dynamics of growth of these nanonclusters
during ion implantation are studied. The concept of formation of a carbonized ion-implanted layer is suggested, which takes
into consideration the formation of lower unsaturated compounds (dienes, trienes) and primitive carbon clusters, cluster growth
and formation of saturated and unsaturated intercluster bridge bonds. Moreover, an investigation is made of the side process
of compensation of broken carbon bonds due to interaction with atmospheric oxygen.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 65, No. 3, pp. 377–381, May–June, 1998. 相似文献
13.
Summary We report room temperature time-resolved photoluminescence (PL) and temperature dependence of continuous wave (cw) PL studies
of high fluence (from 3·1016 to 3·1017 cm−2) Si+-implanted thermal SiO2 layers after annealing at high temperature (T=1000°C). Such measurements were related to TEM analysis of samples. Nancocrystals were observed at TEM only a samples implanted
at higher fluence. In these samples a near infrared PL signal peaked at approximately 1.5 eV with decay time of about 100
μs is present. Besides, in all samples a light emission is present in the green region of the spectrum. The intensity of the
emission shows large variations with ion fluence, and is characterized by 0.4, 2 and 7 ns decay times.
Paper presented at the III INSEL (Incontro Nazionale sul Silicio Emettitore di Luce) Torino, 12–13 October 1995. 相似文献
14.
A four-detector perturbed angular correlation (PAC) spectrometer has been developed with ultra-fast BaF2 detectors to acquire four coincidence spectra simultaneously, two at 180° and two at 90°. This spectrometer has double efficiency
compared to that of a three-detector set-up. Higher efficiency is desirable for PAC studies in solid state physics where large
number of coincidences are required to obtain the PAC spectra with good statistics and is particularly useful when the half-lives
of the parent probe nuclei used for PAC measurements are ∼2–3 days or less as in 111In (2.8 d), 99Mo (2.7 d) and 140La (1.7 d). The performance of the spectrometer has been tested for the HfO2 monoclinic crystal in the temperature range from 77 to 873 K and for the HfF4·3H2O crystal at room temperature. The polycrystalline HfO2 has been synthesized from Hf metal by heating in air. The hydrated hafnium fluoride has been crystallized by dissolving Hf
metal in 40% HF and drying slowly at room temperature.
相似文献
15.
In the paper the dependence of the photorefraction (PhR) in LiNbO3 and LiNbO3−Fe (0.1 wt%, 0.3wt%) crystals on light intensity (within 1016–1023 quanta·cm−2·s−1 at wavelengths 496.5 nm and 600 nm) and temperature (in the region 100–500 K) is studied. For all the crystals the limiting
values of PhR are similar and atT=293 K Δn
sat
lim
≈3·10−3. In LiNbO3 the temperature dependence of PhR in the range 100–500 K requires to take into account at least two trapping centres. 相似文献
16.
A. P. Losev S. M. Bachilo D. I. Volkovich Yu. S. Avlasevich K. N. Solov’yov 《Journal of Applied Spectroscopy》1997,64(1):62-71
Photoinduced electron transfer (PET) in a Pd-porphyrin-quinone complex (Pd-P-Q) was investigated using the flash photolysis
method in microsecond and picosecond range and by luminescence. The investigations were performed for toluene solutions. Intramolecular
PETs in the lower excited singlet state (kCT=1.7·1010 sec−1) and in the triplet state (kCT=2.5·108sec−1) were observed. For a quantum yield of the triplet state that is close to 1 in Pd-porphyrin (Pd-P) this yield is equal to
0.4 in Pd-P-Q. This decrease is the result of PET in the excited state and, possibly, in an unrelaxed triplet state. Triplet
Pd-P-Q molecules were efficiently quenched by unexcited molecules, and this process is related to intermolecular charge transfer.
This electron transfer is likely to occur from the Pd-P protion of an excited molecule to the quinone protion of an unexcited
molecule in the collisional complex (Pd-P-Q)2. Charged radicals, formed once the collisional complex is transferred and separated, have a wide absorption band with a maximum
of about 960 nm. The average lifetime of the radicals was about 2 msec.
Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No 1 pp. 61–70, January–February, 1997. 相似文献
17.
Characteristics of nonlinear optical phenomena in reflection of light at the interface with photorfractive crystals having
photovoltaic nonlinearity are studied. it is shown that under total reflection, hysteretic behavior of the reflection coefficient
is possible as a function of the incident radiation intensity or the angle of incidence. It is important that previously required
threshold intensities are rather low (≤1 W/cm2) in comparison with the known case of reflection from media with Kerr nonlinearity. The present results are of doubtless
interest in view of the development of possible devices for controlling laser radiation.
Interdepartmental Institute of Advanced Training of Personnel in New Trends in Engineering and Technology at the State Polytechnical
Academy of Belarus, 77, Partizanskii Ave., Minsk-107, 220600 Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol.
65, No. 6, pp. 915–920, November–December, 1998. 相似文献
18.
I. V. Kozlov V. B. Odzhaev V. N. Popok I. I. Azarko E. I. Kozlova 《Journal of Applied Spectroscopy》1998,65(4):583-588
Films of polyethylene, polyethylene terephthalate, and polyamine-6 implanted with B+ and N+ ions with an energy of 100 keV are investigated by an EPR method in a dose interval of 1·1014–1·1017 cm−2. It is shown that paramagnetic centers with g=2.0025 formed in the implanted polymers have a nature similar to the nature
of paramagnetic centers of pyrolized and initially conducting polymers. Correspondence of the character of the variation in
paramagnetic characteristics of the modified polymers to the model proposed earlier for the formation of pyrocarbon “drops”
in ion implantation is revealed. The relaxation times for paramagnetic centers in the implanted polymer films are calculated
and assumptions are made about the formation of a quasi-two-dimensional electron gas as well as the possibility of magnetic
ordering in polymer-film layers modified by high-dosage implantation. The effect of oxygen on the electron states of the implanted
polymer specimens is studied.
Belarusian State University, 4, Skorina Ave., Minsk, 220050 Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol.
65, No. 4, pp. 562–567, July–August, 1998. 相似文献
19.
The lattice parameters of CdF2 andβ-PbF2 have been determined over the temperature range 300–670 K. The coefficient of expansion at room temperature is 21·3 × 10−6 K−1 and 25·4 × 10−6 K−1 for CdF2 and PbF2 respectively and it increases linearly with temperature over the range of temperature covered. The Grüneisen parameter decreases
with temperature in both the crystals. 相似文献
20.
E. Mezzetti B. Minetti F. Abbattista M. Vallino D. Andreone V. Lacquaniti R. Cherubini 《Il Nuovo Cimento D》1990,12(7):1017-1020
Summary Pellets of sintered YBa2Cu3O7−δ with three different oxygen contents have been irradiated with fast neutron beams of energies 6.5, 3.3 and 4.4 MeV at fluences
of 7.7·104, 1.3·105 and 1.4·109 n/cm2, respectively. The radiation damage has been investigated by comparing the critical temperature (T
c
mid
), the zero resistivity and the onset temperature before and after neutron irradiation. The critical current has been measured
for a few samples in the same experimental conditions. In all transport measurements two different responses to the neutron
radiation are observed and discussed. 相似文献