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1.
I. Kh. Abdukadyrova 《Journal of Applied Spectroscopy》2007,74(2):278-282
Features of the thermoradiative changes in the optical absorption and luminescence spectra of leucosapphire (colorless sapphire)
crystals irradiated by neutron fluences within the range 5·1015 to 5·1019 cm−2 have been studied in the visible region. The stepwise character of these processes was established as well as the basic steps
involved in bleaching the induced color of the wafers as a result of isochronal annealing. Some anomalies have been observed
in the temperature dependence of the optical density of the 460–620 nm bands, the activation energies for the color centers
as well as the color center concentrations have been calculated, and the nature of the radiation-induced centers has been
analyzed. An analytical expression is proposed to describe the accumulation kinetics for the centers during irradiation of
the crystals by reactor neutrons. It is concluded that there is an interconnection between, for example, the 460 nm color
centers and the 540 nm luminescence centers, and that there is a common mechanism for the process of radiation-induced defect
formation, initially responsible for their formation in the crystal. The possible effect of reabsorption of radiation on the
behavior of the Y(Φ) curve in the irradiated material is discussed.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 247–251, March–April, 2007. 相似文献
2.
X. Y. Tao I. Fsaifes V. Koncar C. Dufour C. Lepers L. Hay B. Capoen M. Bouazaoui 《Applied Physics A: Materials Science & Processing》2009,96(3):741-749
Indium tin oxide (ITO) thin films prepared by the sol–gel method have been deposited by the dip-coating process on silica substrates. CO2 laser is used for annealing treatments. The electrical resistivity of sol–gel-derived ITO thin films decreased following
crystallization after exposure to CO2 laser beam. The topological and electrical properties of the irradiated surfaces have been demonstrated to be strongly related
to the coating solution and to the laser processing parameters. Optimal results have been obtained for 5 dip-coating layers
film from 0.4 mol/l solution irradiated by 0.6 W/m2 laser power density. In this case, homogeneous and optically transparent traces were obtained with a measured sheet resistance
of 1.46×102 Ω/□. 相似文献
3.
Balram Tripathi Y. K. Vijay F. Singh D. K. Avasthi S. Wate 《Indian Journal of Physics》2009,83(12):1659-1665
Iron doped CdS nanocrystals have been synthesized by using aqueous solution precipitation method. Samples of CdS:Fe have been
subjected to irradiation using C+6 (80 MeV) under of 1×1013 ions/cm2. For characterization, X-ray diffraction (XRD), Photoluminescence (PL) and Optical absorption studies have been performed.
The system has been found in hexagonal phase having particle size distribution 18–20 nm. Photoluminescence intensity has been
found to decrease, while optical band gap has been found to increase in irradiated samples. 相似文献
4.
M. Jubera J. Villarroel A. García-Caba?es M. Carrascosa J. Olivares F. Agullo-López A. Méndez J. B. Ramiro 《Applied physics. B, Lasers and optics》2012,107(1):157-162
The propagation losses (PL) of lithium niobate optical planar waveguides fabricated by swift heavy-ion irradiation (SHI),
an alternative to conventional ion implantation, have been investigated and optimized. For waveguide fabrication, congruently
melting LiNbO3 substrates were irradiated with F ions at 20 MeV or 30 MeV and fluences in the range 1013–1014 cm−2. The influence of the temperature and time of post-irradiation annealing treatments has been systematically studied. Optimum
propagation losses lower than 0.5 dB/cm have been obtained for both TE and TM modes, after a two-stage annealing treatment
at 350 and 375∘C. Possible loss mechanisms are discussed. 相似文献
5.
V. N. Detsik S. A. Kukushkin A. V. Osipov E. Yu. Kaptelov I. P. Pronin 《Physics of the Solid State》1997,39(1):104-108
The nucleation and growth of islands of a new phase on the surface of solids has been studied both experimentally and theoretically
for the particular case of the transition from the pyrochlore to perovskite phase in a thin film of a lead zirconate-titanate
ferroelectric. This transformation was chosen because the new-phase islands have a stable circular shape in this case, a relatively
large size (10−5–10−4 m) permitting their observation with an optical microscope, and a low growth rate (10−8–10−9 m/s). A theoretical analysis of the process, based on the kinetic theory of first-order phase transitions proposed earlier,
has been carried out and the behavior in time of all main characteristics of a phase transformation, namely, nucleation rate,
concentration of the new-phase islands, their size distribution, and relative overheating, has been calculated. The same characteristics
have been measured experimentally, thus permitting one for the first time to make a thorough comparison of the theoretical
with experimental data on the kinetics of first-order phase transitions. They have been found to be in a good agreement.
Fiz. Tverd. Tela (St. Petersburg) 39, 121–126 (January 1997) 相似文献
6.
G. V. Lysova G. A. Birzhevoy 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(2):118-121
Ferritic-martensitic 12Cr-MoWSiVNbB (EP-823) steel was irradiated with 7 MeV Ni++ ions within fluence interval 5 × 1018−5.4 × 1019 ions/m2 and with 30 and 70 keV He+ ions within fluence interval 1020–1021 ions/m2 at 500°C. Results from a comparative analysis of Cr and Si radiation-induced segregation profiles near the surface are presented.
Dependence of the amount of surface segregation on damage dose, displacement generation rate, and radiation-induced point
defects concentration is established. 相似文献
7.
A model of electron transfer by tunneling between trapped electron and hole centers in crystals with hydrogen bonds under
the conditions of thermostimulated mobility of one carrier type in the recombination process has been developed. The proposed
model describes all features in the kinetics of induced optical density relaxation observed in nonlinear optical crystals
of KH2PO4 (KDP) and NH4H2PO4 (ADP) on a wide temporal scale (10−8–10 s) under pulsed irradiation. The results of model calculations have been compared with experimental data on the photoinduced
transient optical absorption (TOA) in KDP and ADP crystals in the visible and UV ranges. The nature of the radiation-induced
defects, which account for the TOA, and the dependence of the TOA decay kinetics on the temperature, excitation power, and
other experimental conditions have been considered. 相似文献
8.
P. Haro-González I. R. Martín S. González-Pérez L. L. Martin F. Lahoz D. Puerto J. Solís 《Applied Physics A: Materials Science & Processing》2010,98(4):879-884
Localized modification of the optical properties of erbium doped strontium barium niobate (SBN) glass has been performed using
femtosecond laser irradiation. The samples, with composition SrO–BaO–Nb2O5–B2O5 and doped with 5%mol of Er3+, were fabricated using a melt-quenching method. The samples were irradiated with different number of pulses per spot (1–50
pulses) at two different laser fluences (2.6 and 5.6 J/cm2) by using an fs laser amplifier operating at 800 nm and generating pulses with a duration of 120 fs.
Micro-luminescent microscopy, using an Ar+ laser as excitation source, has been used to analyze the modifications of the luminescent properties of the sample upon fs
laser exposure. The emissions of the Er3+: 4I11/2→4I15/2 and 4I13/2→4I15/2 transitions allow appreciating the structural modifications caused by femtosecond laser exposure. The lifetimes of the levels
involved in these transitions were measured inside and outside the laser irradiated region. These measurements have been compared
with those obtained in bulk glass ceramic sample, which is obtained from the glass precursor by a thermal treatment in order
to estimate the optimal conditions to produce nanocrystals in a localized region by ultrafast laser irradiation. 相似文献
9.
Alkaline solid polymer electrolyte films have been prepared by the solvent-casting method. Gamma radiation treatment and propylene
carbonate plastisizer were used to improve the ionic conductivity of the electrolytes at ambient temperature. The structure
of the irradiated electrolytes changes from semi-crystalline to amorphous, indicating that the crosslinking of the polymer
has been achieved at a dose of 200 kGy. The ionic conductivity at room temperature of PVA/KOH blend increases from 10−7 to 10−3 Scm−1 after the PVA crosslinking and when the plasticizer concentration was increased from 20 to 30%.
Paper presented at the International Conference on Functional Materials and Devices 2005, Kuala Lumpur, Malaysia, June 6 –
8, 2005. 相似文献
10.
F. Machalett K. Edinger J. Melngailis M. Diegel K. Steenbeck E. Steinbeiss 《Applied Physics A: Materials Science & Processing》2000,71(3):331-335
For direct writing of electrically conducting connections and areas into insulating gold oxide thin films a scanning Ar+ laser beam and a 30 keV Ga+ focused ion beam (FIB) have been used. The gold oxide films are prepared by magnetron sputtering under argon/oxygen plasma.
The patterning of larger areas (dimension 10–100 μm) has been carried out with the laser beam by local heating of the selected
area above the decomposition temperature of AuOx (130–150 °C). For smaller dimensions (100 nm to 10 μm) the FIB irradiation could be used. With both complementary methods
a reduction of the sheet resistance by 6–7 orders of magnitude has been achieved in the irradiated regions (e.g. with FIB
irradiation from 1.5×107 Ω/□ to approximately 6 Ω/□). The energy-dispersive X-ray analysis (EDX) show a considerably reduced oxygen content in the
irradiated areas, and scanning electron microscopy (SEM), as well as atomic force microscopy (AFM) investigations, indicate
that the FIB patterning in the low-dose region (1014 Ga+/cm2) is combined with a volume reduction, which is caused by oxygen escape rather than by sputtering.
Received: 30 May 2000 / Accepted: 31 May 2000 / Published online: 13 July 2000 相似文献
11.
AMBIKA NEGI R V HARIWAL ANJU SEMWAL R G SONKAWEDE D KANJILAL J M S RANA R C RAMOLA 《Pramana》2011,77(4):707-714
In the present study, the effects of swift heavy ion beam irradiation on the structural, chemical and optical properties of
Makrofol solid-state nuclear track detector (SSNTD) were investigated. Makrofol-KG films of 40 μm thickness were irradiated with oxygen beam (O8 + ) with fluences ranging between 1010 ion/cm2 and 1012 ion/cm2. Structural, chemical and optical properties were investigated using X-ray diffraction, FTIR spectroscopy and UV–visible
spectroscopy methods. It is observed that the direct and indirect band gaps of Makrofol-KG decrease after the irradiation.
The XRD study shows that the crystalline size in the films decreases at higher fluences. The intensity plots of FTIR measurements
indicate the degradation of Makrofol at higher fluences. Roughness of the surface increases at higher fluence. 相似文献
12.
Thermal and optical properties of unirradiated and γ-irradiated polyester track detector films in the dose range of 0–14.5
Mrad have been studied by thermogravimetry (TG) and UV-Visible spectroscopic technique. The samples were irradiated with 60Co γ-rays for doses of 4.7, 8.1 and 14.5 Mrad. The TG studies indicate that unirradiated and the γ-irradiated samples degrade
in two steps. The kinetics of the two steps of degradation were also evaluated from the TG curves. Irradiation enhances the
degradation rate and the effect increases further with increasing radiation dose. The optical band gaps of the unirradiated
as well as the irradiated samples were also determined from the UV-Visible spectra. These studies can be used for the estimation
of γ-dose using changes in absorbance and the activation energy due to γ-irradiation. 相似文献
13.
A. Ya. Faenov S. A. Pikuz A. G. Zidkov I. Yu. Skobelev P. S. Komarov O. V. Chefonov S. V. Gasilov A. V. Ovchinnikov 《JETP Letters》2010,92(6):375-378
The characteristics of X rays of a laser plasma generated in the interaction of a femtosecond pulse with solid targets in
an air atmosphere have been investigated. It has been shown that the mechanism for the generation of X rays in the interaction
of short intense laser pulses with solid targets in a gas atmosphere is attributed to the generation of fast electrons in
the region of the filamentation of a laser pulse. It has been proven experimentally that under such conditions, the solid
target irradiated by laser radiation of even a low density of about 1015 W/cm2 very efficiently emits ∼10-keV photons. It has been shown theoretically that the maximum energy of accelerated electrons
can reach ɛmax ∼ 100–200 keV under these conditions. This means that the proposed method can provide characteristic radiation with the energy
of photons much higher than 10 keV. 相似文献
14.
B. A. Kalin N. V. Volkov E. A. Anan’eva 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(3):538-542
The results of investigating the wear resistance of E110 alloy samples irradiated by a He+ + Ar+ beam with a wide energy spectrum are presented. Surface modification under irradiation by an Ar+ beam at doses higher than 2 × 1018 ion/cm2 is shown to cause substantial enhancement of the wear resistance of samples because the structural homogeneity of near surface
layers increases, the surface roughness decreases, and its microhardness increases. The application of a mechanical-geometrical
wear model based on the experimental wear characteristics determined during accelerated tests indicates that the thinning
of an alloy cladding can reach rates of 10−6–10−3 mm/s, which agree satisfactorily with data obtained in other simulation experiments. The presence of an oxide film changes
a wear process characterized by an abrasive component. 相似文献
15.
Silicon diodes with a p
+-n junction made in a 48-μm-thick phosphorus-doped silicon epilayer (resistivity ρ = 30 Ω cm) grown on antimony-doped Si(111)
wafers (ρ = 0.01 Ω cm) are studied. The diodes are irradiated by high-energy (3.5 MeV) electrons with fluences from 5 × 1015 to 2 × 1016 cm−2. It is shown that the conventional equivalent circuit of the diode that consists of a parallel RC network and a series-connected resistor inadequately describes the dependence of the dielectric loss tanδ on variable current
frequency f in the range 1 × 102–3 × 107 Hz. Another equivalent circuit is suggested that includes not only the capacitance and resistance of the n-base (the latter increases because radiation-induced defects are compensated for by shallow donors) but also the f dependence of the capacitance of the space-charge region, which is due to retarded charge exchange between deep-level radiation-induced
defects. 相似文献
16.
Ag/Fe bilayers in which a submonolayer of 111In had been deposited in the Fe layer at a distance of x=0–17 nm from the interface, were irradiated at 80 K with 450 keV
Xe ions to a fluence of 3 and 6⋅ 1015 ions/cm2. Perturbed Angular Correlation spectroscopy was used to monitor the microsurrounding of the 111In tracers and to identify the radiation-induced defects. The fraction of tracer atoms being transported into the Ag layer
cannot be explained by ballistic mixing, but is reproduced when assuming local thermal spikes to develop. The diffusion of
111In into the Ag layer can be modeled if the local spikes have an average diameter of some 5 nm.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
K. Yamasaki S. Juodkazis T. Lippert M. Watanabe S. Matsuo H. Misawa 《Applied Physics A: Materials Science & Processing》2003,76(3):325-329
We report the reversible micro-structuring of a synthetic rubber polymer (cis1,4-polybutadiene (PB)) by femtosecond laser
illumination. Visco-elastic relaxation of the optically damaged region was observed. The recovery time, typically 102–104 ms, can be varied by changing the irradiation pulse energy. Multi-shot-induced damage recovers on the much longer scale of
101–102 s. It was found that the doping of PB by 4 wt. % of pentazadiene ([4-NO2]–phenyl–N=N–N(C3H7)–N=N–phenyl–[4-NO2]) reduces the threshold of light-induced photo-modification by 20%. This is explained by photo-induced (homolytic) cleavage
of the pentazadiene bonds and formation of gaseous N2, which facilitates material failure at the irradiated spot.
The recovery of optical transmission can be applied to optical memory, optical and micro-mechanical applications. The underlying
mechanism of the phenomenon is discussed in terms of anelastic α- and β-relaxation (polymer backbone and chains/coils relaxation,
respectively).
Received: 11 October 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +81-88/656-7598, E-mail: misawa@eco.tokushima-u.ac.jp 相似文献
18.
The behavior of the impedance spectra of island permalloy films prepared through vacuum evaporation onto optically polished
glass-ceramic substrates has been investigated in the frequency range from 0.0001 to 100 MHz. A resistor-capacitor model of
the films has been developed and the model parameters, for which there is a good agreement with experimental data on the frequency
dependences of the real and imaginary components of the impedance, have been determined. The specific features in the behavior
of the electrical and physical characteristics with variations in the thickness of the sample and the gap between the measuring
electrodes have been investigated. It has been found that the relative permittivity of the films under investigation reaches
values ɛ ∼ 107–108. The structural relaxation times have been calculated. 相似文献
19.
The thermal- and photo-induced transformations of luminescence centers in anion-defective crystals of α-Al2O3 have been investigated. It has been found that the exposure of crystals to ultraviolet light at temperatures in the range
50–900°C leads to substantial changes in their thermoluminescence and radioluminescence spectra. According to the optical
absorption and photoluminescence data, the detected F-type centers have been identified and the temperature ranges of the F → F
+ → F
2 transformations and their possible mechanisms have been determined. The special attention has been drawn to the detailed
similarity in the formation of complex F
2-type centers in the initially perfect α-Al2O3 crystals irradiated with fast neutrons and in the studied anion-defective crystals. 相似文献
20.
I. S. Edelman E. A. Petrakovskaja D. A. Petrov S. M. Zharkov R. I. Khaibullin V. I. Nuzhdin A. L. Stepanov 《Applied magnetic resonance》2011,40(3):363-375
Fused silica plates have been implanted with 40 keV Co+ or Ni+ ions to high doses in the range of (0.25–1.0) × 1017 ions/cm2, and magnetic properties of the implanted samples have been studied with ferromagnetic resonance (FMR) technique supplemented
by transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. The high-dose implantation
with 3d-ions results in the formation of cobalt and nickel metal nanoparticles in the irradiated subsurface layer of the SiO2 matrix. Co and Ni nanocrystals with hexagonal close packing and face-centered cubic structures have a spherical shape and
the sizes of 4–5 nm (for cobalt) and 6–14 nm (for nickel) in diameter. Room-temperature FMR signals from ensembles of Co and
Ni nanoparticles implanted in the SiO2 matrix exhibit an out-of-plane uniaxial magnetic anisotropy that is typical for thin magnetic films. The dose and temperature
dependences of FMR spectra have been analyzed using the Kittel formalism, and the effective magnetization and g-factor values have been obtained for Co- and Ni-implanted samples. Nonsymmetric FMR line shapes have been fitted by a sum
of two symmetrical curves. The dependences of the magnetic parameters of each curve on the implantation dose and temperature
are presented. 相似文献