共查询到20条相似文献,搜索用时 687 毫秒
1.
E. D. Skakovskii L. Yu. Tychinskaya O. A. Gaidukevich A. Yu. Klyuev A. N. Kulakova N. M. Petlitskaya S. V. Rykove 《Journal of Applied Spectroscopy》2007,74(4):584-588
We studied the fatty-acid composition of oils from pine nuts and seeds of common pine using PMR and 13C NMR and gas chromatography. We found that the main components of the glycerides are palmitic, stearic, oleic, linoleic,
γ-linolenic, pinolenic, and cis-9-eicosenoic acids. The oils contain about 2% sn-1,2-diacylglycerides in addition to triglycerides.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 4, pp. 528–532, July–August, 2007. 相似文献
2.
E. D. Skakovskii L. Yu. Tychinskaya O. A. Gaidukevich N. G. Kozlov A. Yu. Klyuev S. A. Lamotkin S. I. Shpak S. V. Rykov 《Journal of Applied Spectroscopy》2008,75(3):439-443
We have used 1H and 13C NMR spectroscopy to study the composition of pine resin balsams from Scotch pines grown in different regions of the Republic
of Belarus. We have established that their chemical composition does not depend very much on the region where they are grown
or the level of contamination of the forests by radioactive and industrial emissions. Prolonged storage of the balsams leads
to a substantial change in their compositions, due to isomerization of the resin acids.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 411–415, May–June, 2008. 相似文献
3.
We have used 1H and 13C NMR spectroscopy to analyze the chemical composition of essential oil from needles of Canadian spruce (Picea glauca (Moench) Voss) grown in different regions of the Republic of Belarus. We consider the change in the composition of the oil depending on the area where the spruce was grown. We suggest using spruce needle essential oil as a biological indicator for environmental conditions in the area. 相似文献
4.
V. I. Ozhogin N. A. Babushkina L. M. Belova A. P. Zhernov E. E. Haller K. M. Itoh 《Journal of Experimental and Theoretical Physics》1999,88(1):135-137
The first experimental and theoretical investigation of the difference in the temperature behavior of the linear expansion
coefficients of single crystals grown from isotopically highly enriched and natural germanium is reported. A comparison of
the data for 70Ge and natGe crystals reveals the significant influence of isotopic composition over a wide range of temperatures 30–230 K.
Zh. éksp. Teor. Fiz. 115, 243–248 (January 1999) 相似文献
5.
We report on the first layer growth of a Mn6+-doped material. Large-size BaSO4 substrates of 10×6×4 mm3 were grown from a LiCl solvent by the flux method. Flat surfaces of undoped BaSO4 were then achieved by use of liquid-phase epitaxy (LPE) from a CsCl–KCl–NaCl solvent. Finally, BaSO4:Mn6+ layers were grown by LPE with growth velocities of approximately 3 μm h-1, at temperatures of 550–508 °C. Absorption, luminescence, luminescence-excitation and luminescence-decay measurements confirmed
the incorporation of manganese solely in its hexavalent oxidation state. This material possesses potential as a near-infrared
tunable laser with a wavelength range larger than Ti:sapphire.
Received: 7 January 2002 / Revised version: 30 March 2002 / Published online: 8 August 2002 相似文献
6.
Prediction and Measurement of Electron Density and Collision Frequency in a Weakly Ionised Pine Fire
Kgakgamatso Mphale Mohan Jacob Mal. Heron 《International Journal of Infrared and Millimeter Waves》2007,28(3):251-262
Pine litter flame is a weakly ionised medium. Electron-neutral collisions are a dominant form of particle interaction in the
flame. Assuming flame electrons to be in thermal equilibrium with neutrals and average electron-neutral collision frequency
to be much higher than the plasma frequency, the propagation of microwaves through the flame is predicted to suffer signal
intensity loss. A controlled fire burner was constructed where various natural vegetation species could be used as fuel. The
burner was equipped with thermocouples and used as a cavity for microwaves with a laboratory quality network analyzer to measure
wave attenuation. Electron density and collision frequency were then calculated from the measured attenuation. The parameters
are important for numerical prediction of electromagnetic wave propagation in wildfire environments. A controlled pine litter
fire with a maximum flame temperature of 1080 K was set in the burner and microwaves (8–10.5 GHz) were caused to propagate
through the flame. A microwave signal loss of 1.6–5.8 dB was measured within the frequency range. Based on the measured attenuation,
electron density and electron-neutral collision frequency in pine fire were calculated to range from 0.51–1.35 × 1016 m−3 and 3.43–5.97 × 1010 s−1 respectively. 相似文献
7.
Yu. V. Zorenko R. M. Turchak T. I. Voznyak Yu. B. Mamai 《Journal of Applied Spectroscopy》2006,73(3):406-410
We have used the Bridgman method to grow CsBr:Eu2+ single crystals, adding an activator to the mix in the form of Eu2O3 in amounts of 0.0125, 0.0250, and 0.0500 mole %. At T = 300 K, we studied the absorption spectra, the photoluminescence (PL)
spectra, and the photostimulated luminescence (PSL) spectra of the grown crystals. We have established that the structure
of the photoluminescence and photostimulated luminescence centers in crystals grown from the CsBr:Eu2O3 mix includes isolated dipole centers Eu2+-VCs, emitting in bands with maxima at 432 nm and 455 nm respectively, and in crystals grown at activator concentrations of 0.025
and 0.050 mole % they also include aggregate centers (AC) based on CsEuBr3 nanocrystals with emission bands at 515 m and 523 nm. We have shown that the maximum concentration of aggregate centers of
the CsEuBr3 nanocrystal type in CsBr:Eu2+ crystals is achieved for an activator content in the mix within the range 0.01–0.05 mole %.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 359–362, May–June, 2006. 相似文献
8.
We obtain experimental data on the complex refractive index N = n+ik of petroleum, five petroleum oils, and water-petroleum
emulsion in the frequency range f = 75–120 GHz. Measurements were performed in a quasioptical equipment with a backward-wave
oscillator generating the radiation and an OAP-7 optical-acoustic receivers for a temperature of 27°C of studied liquids.
The refractive indices n of petroleum and oil have a weak negative dispersion (dn/df < 0) and close values. At a frequency of 100 GHz, they lie in the range n = 1.477–1.495. The absorption indices k have different
frequency dependences such that k increases for four oils, while it decreases for petroleum and SM-4.5 oil with increasing
f. At the frequency f = 100 GHz, the values of k vary in a wide range from 2.4 · 10−4 to 1.7 · 10−3. The measurement results for petroleum and oils are compared with experimental results obtained by other authors. The frequency
dependences of n and k of water-petroleum emulsion for water concentrations 0.11% and 0.58% are compared with the data calculated
using various analytical models of dielectric mixtures. The dependences n(f) and k(f) calculated by the Kubo-Nakamura formula
are the closest to the experimental data.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 6, pp. 485–495, June 2007. 相似文献
9.
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.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 86–89, January–February, 2006. 相似文献
10.
A. S. Yasyukevich A. V. Mandrik N. V. Kuleshov E. Yu. Gordeev S. L. Korableva A. K. Naumov V. V. Semashko P. A. Popov 《Journal of Applied Spectroscopy》2007,74(6):844-850
Yb3+ (2.7 at.%):Na4Y6F22 and Yb3+(1 at.%):LiLuF4 crystals were grown by the Bridgman-Stockbarger method. We measured the temperature dependences of the thermal conductivity
of the crystals and the absorption spectra. We determined the radiative lifetime of the Yb3+ ion in these crystals (1.94 msec and 2.13 msec) and calculated the stimulated emission cross section spectra.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 761–766, November–December, 2007. 相似文献
11.
G. A. Bufetova M. Yu. Gusev I. A. Ivanov N. S. Neustroev D. A. Nikolaev V. F. Seregin V. B. Tsvetkov I. A. Shcherbakov 《Physics of Wave Phenomena》2009,17(2):77-91
An efficient technology was developed for growing the gadolinium gallium garnet (GGG) single-crystal films doped with Nd3+ or Cr and Ca ions. The films with thickness up to 100 μm have been grown by liquid-phase epitaxy method on undoped GGG substrates
of small and big sizes (5–8 mm and up to 76 mm in diameter, respectively). The dependence of absorption, luminescence spectra
and optical losses at the wavelength of 1 μm on growth temperature and melt-solution composition was studied. We demonstrated
that Cr4+ centers have been implemented in epitaxial films and these films may be used as passive Q-switches for laser systems. 相似文献
12.
V. I. Korepanov V. M. Lisitsyn V. I. Oleshko E. F. Polisadova S. S. Vil’chinskaya 《Journal of Applied Spectroscopy》2006,73(3):382-387
We have studied the spectral and kinetic characteristics of pulsed cathodoluminescence of feldspars (albite, microcline, amazonite)
in the time range 10−8–10−2 sec and the temperature range 28–300 K. We have shown that the bands in the UV region of the spectrum (5.39, 4.35, and 3.75
eV) are due to intrinsic luminescence of the crystals. The ratio of the intensities of these bands characterizes the phase
composition of the mineral: in the luminescence spectra of microcline, for all temperatures the 4.35 eV band dominates; in
the pulsed cathodoluminescence spectra of albite, the bands at 3.75 eV (at 300 K) and 5.39 eV (at 28 K) dominate. The parameters
of the luminescence decay kinetics for the impurity ions Fe3+ and Mn2+ are more sensitive to local perturbations of the lattice structure than the position of the emission band maximum, and can
be an effective indicator of the origin of the mineral.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 339–343, May–June, 2006. 相似文献
13.
GaSb single crystals were grown by the Czochralski method without encapsulant in an atmosphere of ionized hydrogen. It has
been found that the resistivity increased by more than one order of magnitude (0.8–1.0Ω cm) and free carrier concentration
decreased to the value of (1–2) × 1016 cm−3 in comparison with the crystals grown under molecular hydrogen atmosphere. A certain asymmetry in acceptor and donor passivation
is assumed because the Hall concentration does not vary along the direction of crystal growth. Donors are passivated more
than acceptors, which should be confirmed by increasing resistivity and decreasing mobility.
Presented at the 6th Joint Seminar “Development of Materials Science in Research and Education”, Karlštejn, Czech Republic,
17–19 September 1996. 相似文献
14.
Jose Antonio Ayllon Monica Lira-Cantu 《Applied Physics A: Materials Science & Processing》2009,95(1):249-255
The effects of oxygen content in the sputtering gas on the crystallographic and optoelectronic properties of 210 nm-thick
Zr–doped In2O3 (Zr–In2O3) films by rf magnetron sputtering were initially studied. The results of X-ray diffraction show that the Zr–In2O3 films grown on glass substrates exhibit mixed crystallographic orientations. Moreover, the Zr–In2O3 film grown in an Ar atmosphere promotes the appearance of crystallographic orientation of (222). The surface of the Zr–In2O3 film becomes rougher as the oxygen content in the sputtering gas decreases; the current images obtained by conductive atomic
force microscopy reveal that the surfaces of the Zr–In2O3 films exhibit a distribution of coexisting conducting and nonconducting regions, and that the area of the nonconducting surface
increases with the oxygen content in the sputtering gas. The resistivity is minimized to 3.51×10−4 Ω cm when the Zr–In2O3 film is grown in an Ar atmosphere and the average transmittance in the visible light region is ∼85%. The optical band gap
decreases as the oxygen content in the sputtering gas increases. 相似文献
15.
A. V. Voitsekhovskii S. N. Nesmelov S. M. Dzyadukh V. S. Varavin S. A. Dvoretskii N. N. Mikhailov Yu. G. Sidorov 《Russian Physics Journal》2011,54(3):263-270
The effect of regions with periodic sharp 48–54 nm thick inhomogeneities in composition on the electrophysical characteristics
of MIS structures based on graded-gap n-Hg1–x
Cd
x
Te (x = 0.29–0.31) grown by molecular-beam epitaxy is studied. It is found that major electro-physical and photo-electrical
characteristics are qualitatively similar for MIS structures based on n-Hg1–x
Cd
x
Te with sharp inhomogeneities in composition (barriers) and without “barriers”. It is shown that the electrical characteristics
are mostly affected by the “barrier regions” located close to the insulator – semiconductor interface. This effect is manifested
in an increase of the effective dielectric thickness, which can be due to the fact that the regions of enhanced composition
form potential barriers for electrons, and in a decrease in the relaxation time of non-equilibrium carriers due to recombination
at the boundaries of the regions with sharp changes in composition. 相似文献
16.
H. Kim A. Cepler C. Cetina D. Knies M. S. Osofsky R. C. Y. Auyeung A. Piqué 《Applied Physics A: Materials Science & Processing》2008,93(3):593-598
Present p-type ZnO films tend to exhibit high resistivity and low carrier concentration, and they revert to their natural n-type state
within days after deposition. One approach to grow higher quality p-type ZnO is by codoping the ZnO during growth. This article describes recent results from the growth and characterization
of Zr–N codoped p-type ZnO thin films by pulsed laser deposition (PLD) on (0001) sapphire substrates. For this work, both N-doped and Zr–N
codoped p-type ZnO films were grown for comparison purposes at substrate temperatures ranging between 400 to 700 °C and N2O background pressures between 10−5 to 10−2 Torr. The carrier type and conduction were found to be very sensitive to substrate temperature and N2O deposition pressure. P-type conduction was observed for films grown at pressures between 10−3 to 10−2 Torr. The Zr–N codoped ZnO films grown at 550 °C in 1×10−3 Torr of N2O show p-type conduction behavior with a very low resistivity of 0.89 Ω-cm, a carrier concentration of 5.0×1018 cm−3, and a Hall mobility of 1.4 cm2 V−1 s−1. The structure, morphology and optical properties were also evaluated for both N-doped and Zr–N codoped ZnO films. 相似文献
17.
A. V. Voitsekhovskii A. G. Korotaev A. P. Kokhanenko D. V. Grigor’ev V. S. Varavin S. A. Dvoretskii Yu. G. Sidorov N. N. Mikhailov N. Kh. Talipov 《Russian Physics Journal》2006,49(9):929-933
The dynamics of accumulation of electrically active radiation defects under ion doping of epitaxial Cd
x
Hg
1−x
Te films is studied for various distributions of film composition in the implantation region. The epitaxial films were irradiated
by boron ions at room temperature in the continuous regime, with the dose ranging within 1011−3·1015 cm−2, energy — 20–150 keV, and ion current density — j = 0.001–0.2 μA·cm−2. It is found that the natural logarithm of the introduction rate of electrically active radiation defects linearly depends
on the epitaxial-film composition in the range of mean projected path of implanted ions. An analysis of the experimental data
shows that the dynamics of accumulation of electrically active radiation defects is determined by the epitaxial-film composition
in the implantation region.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 25–28, September, 2006. 相似文献
18.
A. É. Bugrov S. Yu. Gus’kov V. B. Rozanov I. N. Burdonskii V. V. Gavrilov A. Yu. Gol’tsov E. V. Zhuzhukalo N. G. Koval’skii V. N. Kondrashov M. I. Pergament V. M. Petryakov S. D. Tsoi 《Journal of Experimental and Theoretical Physics》1999,88(3):441-448
We have experimentally investigated the interaction of high-power neodymium laser pulses in the intensity range 1013–1014 W/cm2 with flat low-density (0.5–10 mg/cm3) agar-agar targets under conditions of interest for problems of inertial nuclear fusion. Optical and x-ray methods with high
temporal and spatial resolution were used to examine the dependence of absorption and scattering of the incident beam on the
initial mean density and thickness of the irradiated samples. We show that when a porous target is irradiated, a bulk absorption
layer of high-temperature plasma is produced inside the target whose dimensions are determined by the initial density of the
material. The time dependence and spectral composition of the harmonics 2ω
0 and 3ω
0/2 observed in the plasma-scattered radiation are measured. A theoretical model is developed that describes the interaction
of high-power laser pulses with a porous medium. Predictions of the model, based on the hypothesis of two stages of homogenization
of the target material—a fast stage (0.1–0.3 ns) and a slow stage (1–3 ns), are in good agreement with the experimental data.
Zh. éksp. Teor. Fiz. 115, 805–818 (March 1999) 相似文献
19.
We present the results of an investigation of the cathodoluminescence of the Eu2+ ion in gallium chalcogenides (Ga2S3) and europium thiogallate (EuGa2S4). We show that the intense wide-band radiation of these compounds is due to the 4f-5d transitions of the Eu2+ ions. With increase in the Eu2+ percent composition from 0.1 to 5.0 mol.% the luminescence brightness increases and then decreases.
Translated from Zhurnal Prikladnoi Spektrskopii, Vol. 67, No. 2, pp. 268–270, March–April, 2000. 相似文献
20.
E. D. Skakovskii W. P. Kiselev L. Yu. Tychinskaya A. G. Schutova L. W. Gonsharova E. W. Spiridowish N. A. Bovdey P. A. Kiselev O. A. Gaidukevich 《Journal of Applied Spectroscopy》2010,77(3):329-334
The composition of essential oil from Agastache rugosa (Fish. et Mey) O.Kuntze was studied by 1H and 13C NMR spectroscopy. Essential oil was isolated from the aerial part of plants growing in the Central Botanical Garden of the
NAS of Belarus during flowering and fruiting. The oil chemical composition was found to depend little on the sampling time.
It was shown that NMR spectroscopy could be successfully used to both monitor the content of the hepatotoxic substance (pulegone)
and characterize the quality and authenticity of essential oils. 相似文献