共查询到20条相似文献,搜索用时 31 毫秒
1.
The results of investigations of the emission of glow discharges in mixtures of inert gases and halogens in cylindrical tubes
of various dimensions are presented. Glow-discharge-pumped XeCl* and KrCl* excimer lamps with a homogeneous spatial distribution
of the radiation and powers up to 100 W are created. It is shown that the high efficiency of excimer lamps of this type is
achieved as a result of the effective formation of exciplexes in a harpoon reaction and the slow rate of their quenching in
the glow-discharge plasma at low pressures of the working mixture.
Zh. Tekh. Fiz. 68, 64–68 (February 1998) 相似文献
2.
A. K. Shuaibov Z. T. Gomoki A. G. Kalyuzhnaya A. I. Shchedrin 《Optics and Spectroscopy》2010,109(5):669-673
The UV radiation of glow- and capacitive-discharge lamps based on mixtures of inert gases with iodine vapors are optimized
in the spectral range of 175–360 nm, in which working helium-iodine mixtures of different compositions are used. The most
intense spectral lines in the bactericidal region of the spectrum were the atomic lines of iodine (183.0, 206.2 nm), and in
the region of 320–360 nm, emission of the spectral band of an iodine molecule prevailed with a maximum at λ = 342 nm. For
a capacitive lamp with a casing opaque in the spectral range λ < 250 nm, the main part of the plasma emission power is concentrated
in the A′-D′ band of an iodine molecule with a maximum at 342 nm. The emission brightness of this lamp is optimized in iodine molecule
transitions depending on the partial helium pressure. We present the results of simulating the kinetics of processes in a
glow-discharge plasma in mixtures of He, Xe, and iodine vapors. We establish the dependence of the main part of the emission
intensity of the 206.2 nm spectral line of an iodine atom and the 342 nm band of an iodine molecule on the helium pressure
in a glow-discharge lamp operating on a He-I2 mixture. 相似文献
3.
The quasi-continuous wide-aperture glow discharge in helium at pressures from 1.2 to 6.0 Torr is studied. It is found that
electron beam generation efficiency η is higher than 96% in the pressure range 1.2–3.0 Torr at voltages from 1.0 to 2.6 kV.
The maximum power was ≈ 0 kW at 6 Torr and a voltage across the discharge gap of 2.6 kV. Under these conditions, the beam
generation efficiency is about 80%. The pressure and voltage dependences of main parameters of the discharge are explained
from the standpoint of its photoemission nature. 相似文献
4.
K. Yu. Nagulin A. Kh. Gil’mutdinov O. R. Badrutdinov 《Journal of Applied Spectroscopy》2000,67(1):14-21
The spatial distribution of the intensity of radiation from high-frequency electrodeless discharge lamps of LV-2 and VSB-2
types, used as radiation sources in atomic absorption spectrometry, was investigated. Radiation intensity distributions over
the cross section of the lamps were measured on the atomic and ionic lines of a buffer gas and a filler element. It is shown
that in a lamp filled with buffer gas only the distribution of the intensity of atomic and ionic lines is dome-shaped, and
that it is determined by the electron density distribution in the plasma as well as by the mechanism of excitation and ionization
of the buffer gas. The distribution of the intensity of radiation from the filler element is strongly nonuniform, with a maximum
that is concentric with the bulb walls and a minimum on the lamp axis. The observed spatial intensity distributions are explained
by the redistribution of filler-element atoms over the volume of the lamp under the conditions of high electron concentrations.
The time dynamics of the spatial intensity distributions during warm-up of the lamps was investigated. It is shown that the
process of establishment of stationary distributions goes on nonmonotonically, which is due to the redistribution of energy
among different components of the discharge plasma.
Translated from Zhurnal Prikladnoi Spektroskopi, Vol. 67, No. 1, pp. 15–20, January–February, 2000. 相似文献
5.
We report on the role of dye–nucleobase interactions on the photophysical properties of the indocarbocyanine Cy3. The fluorescence
efficiency and lifetime of Cy3 increase in the presence of all four nucleoside monophosphates. This behavior correlates with
an increase in the activation energy for photoisomerization and a ∼4 nm red shift in the fluorescence spectrum. Changes are
more dramatic for the purines (dAMP, dGMP) than the pyrimidines (dCMP, dTMP), and for the nonsulfonated cyanine (DiIC2(3)) than the sulfonated dye (Cy3–SE). These results are consistent with a model in which Cy3–nucleoside π–π interactions
decrease the efficiency of photoisomerization, increasing the efficiency of fluorescence.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
The spatial distribution of the intensity of radiation from LK-2 two-discharge lamps and LD-2 deuterium and halogen lamps,
used in atomic absorption spectrometry, has been investigated. It is shown that the distribution of the intensity of radiation
from a two-discharge lamp is saddle-shaped and is determined by the joint action of the process of cathode sputtering and
of the processes of excitation and ionization of atoms of the filler element under the conditions of a high concentration
of electrons in the positive column of the arc discharge. A dome-shaped distribution of radiation intensity with a maximum
on the axis of the discharge is characteristic of deuterium lamps and is determined by the distribution of the concentration
of electrons in the positive arc column. For halogen lamps, the intensity distribution in the form of a sharp asymmetric peak
is determined by the location and dimensions of the luminescent body made in the form of a spiral. The influence of the spatial
characteristics of the radiation from the sources on the error in measuring atomic absorption by a space-integrating recording
system has beeb evaluated for different radiation intensity distributions. It is shown that this error is negative and reaches
a maximum value for a saddle-shaped distribution of the intensity of transilluminating radiation.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 143–147, March–April, 2000. 相似文献
7.
J. P. Allain M. Nieto-Perez M. R. Hendricks P. Zink C. Metzmacher K. Bergmann 《Applied Physics A: Materials Science & Processing》2010,100(1):231-237
Sn+ irradiations of Ru single-layer mirrors (SLM) simulate conditions of fast-Sn ion exposure in high-intensity 13.5 nm lithography
lamps. Ultra-shallow implantation of Sn is measured down to 1–1.5 nm depth for energies between 1–1.3 keV at near-normal incident
angles on Ru mirror surfaces. The Sn surface concentration reaches an equilibrium of 55–58% Sn/Ru for near-normal incidence
and 36–38% for grazing incidence at approximately 63 degrees with respect to the mirror surface normal. The relative reflectivity
at 13.5 nm at 15-degree incidence was measured in-situ during Sn+ irradiation. For near-normal Sn+ exposures the reflectivity is measured to decrease between 4–7% for a total Sn fluence of 1016 cm−2. Theoretical Fresnel reflectivity modeling shows for the same fluence assuming all Sn atoms form a layer on the Ru mirror
surface, that the reflectivity loss should be between 15–18% for this dose. Ex-situ absolute 13.5 nm reflectivity data corroborate
these results, indicating that implanted energetic Sn atoms mixed with Ru reflect 13.5-nm light differently than theoretically
predicted by Fresnel reflectivity models. 相似文献
8.
The energy characteristics of an XeCl exciplex lamp with planar construction pumped by a low-pressure gas discharge are investigated
experimentally. When a discharge gap of width 2 cm and a Xe-Cl2 mixture were used, average radiation powers up to 20 mW were obtained in the wavelength interval 200–380 nm at efficiencies
of ∼0.4%. In this case the total efficiency of radiation into an angle of 4π exceeded 4%. It is shown that increasing the working pressure and using low discharge currents can lead to “point” radiation
sources.
Zh. Tekh. Fiz. 67, 43–46 (December 1997) 相似文献
9.
Pulsed arc discharges in alkali metal vapours are investigated for use as pump light sources for Nd:YAG lasers. Alkali lamps have a very high radiation efficiency and emit strong lines near the laser pump bands. These absorption bands are fitted by the emission spectrum of sodium and potassium lamps by changing the vapour pressure and input power. The spectral radiation distributions of the lamps are measured by a spectrograph with a gated OMA system. Ray tracing calculations for a laser cavity are used to evaluate the efficiency of the alkali radiation emission for Nd:YAG pumping. The results show that the excitation efficiency of the alkali lamps is twice as high as that of usually used rare gas lamps. For sodium resonance lines the side-on spectral radiance is calculated by a radiation transport model to estimate the pressure and the temperature profile. The results indicate that the alkali vapour lamps could be used as pump light sources with high efficiencies and low heat loading of the laser cavity. 相似文献
10.
K. P. Kureichik S. N. Pupkevich V. S. Granos I. S. Kharamchenkov 《Journal of Applied Spectroscopy》1999,66(5):851-854
We describe a modified GELIOS System intended to automate the atomic-absorption spectrometers AAS, S115, SATURN, and Perkin-Elmer
503. Software is prepared in the visual environment of programming DELFI-3 and functions under the control of Windows 95.
A distinguishing feature of the GELIOS System is simultaneous search for the peak and area of the absorption signal, correction
of the errors of measurements, automatic digital filtration of data, control of the time of operation of hollow-cathode lamps,
measurement of spectra and the statistical resource of the service life of hollow-cathode lamps, use of different methods
to construct a calibrating graph, the possibility of memorizing the data of the analysis in an archived file, and a formation
of the report for printing. The system contains an electrovic data directory on atomicabsorption analysis in five volumes
for 67 elements of the Mendeleev system.
To whom correspondence should be addressed.
“University” Science and Production Center, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi
Spektroskopii, Vol. 66, No. 5, pp. 734–737, September–October, 1999. 相似文献
11.
S. S. Anufrik V. V. Tarkovskii V. M. Nikitchenko 《Journal of Applied Spectroscopy》1999,66(5):772-779
The effect of heterocycles of different types on the fluorescence and generation properties of ten new bifluorophores is investigated
experimentally. It is shown that a number of 7-diethylaminocoumarins with a triazole cycle or an oxydiazole cycle are characterized
by the highest generation efficiency in the region of 500–515 nm. The maximum generation energy was 2.5 J in lamp pumping,
which exceeds widely known coumarin 334 in efficiency by a factor of 1.7. Stabilization of the coumarin fragment by the nucleus
of julolidine—7-N(CH2)6—has a favorable effect on the photostability of these molecules. The effect and the role of the isomer form of the thiazole
fragment on the spectral and generation properties of the molecule are established. A favorable effect on the generation efficiency
of the imino group in the coumarin fragment of the molecule is shown.
Reported at the Second International Scientific and Technical Conference on Quantum Electronics, Minsk, November 23–25, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 675–681, September–October, 1999. 相似文献
12.
J. K. Rath 《Applied Physics A: Materials Science & Processing》2009,96(1):145-152
Nanocrystalline silicon material has made rapid progress in the last several years and at present it can be defined as real
device quality as a photoactive layer for solar cells. A number of innovative ideas, such as the deposition at the crystalline
to amorphous transition, at high pressure depletion condition, by taming of the ion energy, by grading of the material growth,
at reduced unwanted dopant incorporation, have helped to reach an efficiency of 10% for single junction nanocrystalline silicon
cells. In situ plasma and gas phase diagnosis have contributed to the fast optimisation of deposition process parameters.
Deposition rate, open circuit voltage and light confinement are some of most critical issues that are currently pursued. Materials
with a defect density as low as 1015 cm−3 have been made, however, they are still not good enough for n–p junctions; the device structure is still of drift type in
a p–i–n or n–i–p configuration. 相似文献
13.
A. M. Pritulov R. U. Usmanov O. V. Gal’tseva A. A. Kondratyuk V. V. Bezuglov V. I. Serbin 《Russian Physics Journal》2007,50(2):187-192
Interrelation between the compaction pressure of lithium carbonate and iron oxide powder mixture and efficiency of solid-phase
synthesis of lithium pentaferrite are investigated. It is demonstrated that the temperature dependence of the degree of transformation
during isochronous annealing for 60 min obeys the Arrhenius law. The effective activation energy of the process decreases
when the compaction pressure increases from 0.4 (P = 0) to 0.2 eV (P = 202 MPa). A linear dependence between the degree of
transformation and the specific magnetization of the mixture is observed at synthesis temperatures of 870–1070 K. No influence
of the compaction pressure on the magnetic anisotropy field of synthesized spinel is revealed.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 82–86, February, 2007. 相似文献
14.
S.I. Dolgaev S.V. Lavrishev A.A. Lyalin A.V. Simakin V.V. Voronov G.A. Shafeev 《Applied Physics A: Materials Science & Processing》2001,73(2):177-181
The formation and development of the large-scale periodic structures on a single crystal Si surface are studied upon its evaporation
by pulsed radiation of a copper vapor laser (wavelength of 510.6 nm, pulse duration of 20 ns). The development of structures
occurs at a high number of laser shots (∼104) at laser fluence of 1–2 J/cm2 below optical breakdown in a wide pressure range of surrounding atmosphere from 1 to 105 Pa. The structures are cones with angles of 25, which grow towards the laser beam and protrude above the initial surface
for 20–30 μm. It is suggested that the spatial period of the structures (10–20 μm) is determined by the capillary waves period
on the molten surface. The X-ray diffractometry reveals that the modified area of the Si substrate has a polycrystalline structure
and consists of Si nanoparticles with a size of 40–70 nm, depending on the pressure of surrounding gas. Similar structures
are also observed on Ge and Ti.
Received: 12 February 2000 / Accepted: 28 March 2000 / Published online: 20 June 2001 相似文献
15.
A. V. Radaev N. R. Batrakov A. A. Muhamadiev A. N. Sabirzyanov 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(8):1134-1139
An experimental setup was constructed that makes it possible to study oil displacement over wide pressure (up to 20 MPa) and
temperature (up to 373 K) ranges under conditions reproducing the thermobaric, geological, and physicochemical conditions
in real oil beds, as well as the parameters of displacing agents. Experiments on the displacement of kerosene from a model
oil bed with supercritical carbon dioxide at temperatures of 313–353 K and pressures within 7–12 MPa were performed. The results
are indicative of a high efficiency of recovery of low-viscosity oils with supercritical carbon dioxide. 相似文献
16.
D. F. Latfullin I. V. Mursenkova N. N. Sysoev 《Moscow University Physics Bulletin》2009,64(3):352-354
The supersonic air flow at Mach numbers of 1.1–1.6 in a shock tube is experimentally investigated during initiation of nanosecond
pulse surface sliding discharges. The shadow images of the flow field after discharge initiation, which characterize the dynamics
of shock waves propagating from the discharge area, are obtained. Periodic pressure pulsations on the shock tube channel wall
are recorded. The pressure dynamics is shown to correspond to both the motion of shock waves from the discharge area and a
supersonic flow of the discharge-excited gas near the channel wall. The pressure increase on the shock tube channel wall was
6–18%, as compared to the pressure in an unperturbed flow.
Original Russian Text ? D.F. Latfullin, I.V. Mursenkova, N.N. Sysoev, 2009, published in Vestnik Moskovskogo Universiteta.
Fizika, 2009, No. 3, pp. 114–116. 相似文献
17.
P. Kuppusami K. Muthukkumaran R. Divakar R. Kesavamoorthy E. Mohandas S. Selladurai 《Ionics》2007,13(5):343-348
Microstructural properties of nano-ionic thin films of gadolinia-doped ceria (GDC) prepared by pulsed laser ablation from
sintered targets of gadolinia (5–20 mol%) doped ceria are investigated. The ionic conductivity measurements of the sintered
pellets showed a decrease in the activation energy from 1.1 to 0.65 eV for 5 and 30 mol% gadolinia-doped ceria, respectively.
The microstructural properties of the GDC films as a function of substrate temperature, oxygen partial pressure, and laser
energy show that the films are polycrystalline in the entire range of substrate temperature. The grain size is found to increase
with increasing temperature up to 873 K. Further improved crystallinity is noticed for the films grown with oxygen partial
pressure of 0.1–0.2 mbar. X-ray diffraction and transmission electron microscopy (TEM) reveal nanocrystalline grains with
textured growth along <111> orientation in these films at low substrate temperature and at lower oxygen partial pressure.
TEM study shows a uniform distribution of nanocrystal of 8–10 nm for energies ≤200 mJ/pulse, and nanocrystals embedded in
a large crystalline matrix of doped ceria for energies in the range 400–600 mJ/pulse. Raman spectroscopy also confirms the
defects in these films. The study also reveals that the substrate temperature and oxygen partial pressure could influence
preferred orientation, while the laser energy could significantly influence defect concentration in these films.
Invited paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec.
7–9, 2006. 相似文献
18.
Monika Aggarwal M. Husain Samina Khan Zishan H. Khan 《Journal of nanoparticle research》2007,9(6):1047-1055
Carbon nanotubes (CNTs) are synthesized by the catalytic decomposition of acetylene using low pressure chemical vapour deposition
method (LPCVD) at 800 °C and at a chamber pressure of 10 Torr over a supported catalyst film of Fe70Pd30. Morphology of these CNTs is studied using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and
High Resolution Transmission Electron Microscopy (HRTEM). From HRTEM image of these multi-walled carbon nanotubes (MWNTs),
it is clear that these MWNTs do not possess a co-axial cylindrical structure, but are composed of imperfect and broken graphite
cylinders of different sizes. The average diameter and length of the nanotubes varies between 20–70 nm and 5–60 μm respectively.
Electrical transport measurements of these MWNTs are studied over a temperature range of 298–4.2 K. The results have been
interpreted in terms of variable-range hopping (VRH) over the entire temperature range of 298–4.2 K. Three-dimensional variable-range
hopping (VRH) is suggested for the temperature range (298–125 K), while two-dimensional VRH is observed for the temperature
range (125–4.2 K). 相似文献
19.
V. Jirásek J. Hruby O. ?palek M. ?ensky J. Kodymová 《Applied physics. B, Lasers and optics》2010,100(4):779-791
A spray type of singlet oxygen generator for driving the Chemical Oxygen-Iodine Laser was developed. Singlet oxygen, O2(1Δg), is generated by a fast reaction of chlorine with basic hydrogen peroxide solution in the form of a dense spray. A mathematical
model of this reaction system showed that O2(1Δg) can be generated in this system with a high yield (0.70–0.80), high utilization of chlorine (0.75–0.95), and effective utilization
of liquid (0.36–0.54) at very high generator pressures (35–75 kPa). Experimental studies of this reaction system without an
efficient separation of liquid proved an efficient O2(1Δg) production characterized by a rather high product of chlorine utilization and O2(1Δg) yield (0.4–0.9) at very high generator pressures (30–80 kPa). This pressure is much higher than the operation pressure used
in other generators, which should be beneficial for a pressure recovery system of the COIL. These results provided the basis
for designing a centrifugal spray generator with an efficient separation of liquid from the gas flow, which is the subject
of the following paper. 相似文献
20.
R. A. Akhmedzhanov A. L. Vikharev A. M. Gorbachev O. A. Ivanov A. L. Kolysko 《Technical Physics》1997,42(3):260-268
Results are presented from an investigation of the dynamics of ozone formation in a freely localized discharge generated by
a periodic train of 3-cm nanostructured microwave pulses in oxygen and air at a pressure p=3–30 Torr. Conditions for the efficient generation of ozone in air with the minimum production of nitrogen oxides are demonstrated
experimentally. It is shown that when the microwave pulse repetition frequency is high, heating of the gas and the buildup
of nitrogen oxides in the discharge in air reduce the ozone formation efficiency while under prolonged exposure the ozone
formed initially is destroyed. The energy cost of forming ozone in oxygen and air is determined as a function of the microwave
pulse length and repetition frequency and the gas pressure. The lowest energy cost of forming a single ozone molecule in these
experiments is 16 eV per molecule for a discharge in air and 4 eV per molecule in oxygen. It was observed that circulating
the gas through the discharge zone enhances th ozone formation efficiency. It is shown that there are optimal conditions for
ozone formation as a function of the reduced electric field in the plasma.
Zh. Tekh. Fiz. 67, 9–18 (March 1997) 相似文献