共查询到20条相似文献,搜索用时 31 毫秒
1.
利用针阴极和水阳极,在6 mm的空气隙产生了大气压空气辉光放电。该大气压辉光放电具有明显的负辉区、正柱区和阳极辉区等明亮的发光区。通过研究放电的电压电流特性,发现该放电处于亚辉光放电到正常辉光放电阶段。由于氮分子第二正带系337.1 nm的光谱强度反映高能电子密度,对337.1 nm谱线的强度进行了空间分辨测量。结果发现高能电子在针尖附近密度最大,而其他区域相差不多。随电压升高,高能电子密度减少。增大限流电阻,高能电子密度也减少。氧原子对杀菌消毒具有重要作用,利用发射光谱法对氧原子谱线强度的空间分布进行了测量,发现氧原子谱线强度与高能电子的空间分布及其随参数的变化关系一致。 相似文献
2.
格里姆辉光放电光源的发展和应用范围 总被引:2,自引:0,他引:2
本文评述了辉光放电光源的一些进展情况。对高强度辉光放电灯,磁场辉光放电灯,射频、微波辉光放电灯,同轴双重空心阳极辉光放电灯等技术在增加辉光放电光源的发光强度、降低检出限、提高逐层分析中的层间分辨率等方面的作用作了介绍。也同时介绍了这种光源在金属与合金固体样品直接分析及这些材料的表层、逐层分析中的应用范围。 相似文献
3.
D. Zechev R. Dyulgerova R. Angelova 《Journal of Quantitative Spectroscopy & Radiative Transfer》1977,17(2):165-167
The profile of the He 504.7 nm line emitted in the negative glow of a hollow cathode discharge is analyzed as a function of the distance from the emitting volume to the cathode axis. The value of the discharge current varied within the range of 10–30 mA, the helium pressure being 0.4–1.5 torr. A dependence was found of the Voigt parameter a on the location of the emitting volume. The simultaneous recording of two line shapes, emitted from different regions of the discharge, enables us to observe a shift δv of the line center observed off-axis compared with the line emitted along the axis. The electric field intensity at the periphery, 6 mm off-axis, is evaluated on the assumption that Starkbroadening is the cause of δv. 相似文献
4.
利用光谱学方法,对针-水电极和针-板电极直流辉光放电特性进行了比较研究。结果发现两种装置产生的放电都有明显的分区现象, 从阴极到阳极分别为负辉区、阴极暗区、正柱区和阳极辉区。针-板电极放电中可以清晰地观测到阳极暗区, 而针-水电极放电阳极暗区不明显。对比两种放电的伏安特性曲线,发现放电电压均随电流增大而减小,但相同电流下针-水电极间的电压大于针-板电极间的电压。由于伏安特性具有负斜率,且放电电流密度介于10-5~10-4 A·cm-2,说明两种装置中的放电均处于正常辉光放电阶段。在正常辉光放电的范围内比较两种放电的发射光谱, 发现发射光谱中都包含N2的第二正带系(含波长为337.1 nm的谱线)和N+2的第一负带系(含波长为391.4 nm的谱线),但相对强度不同。利用光谱学方法对放电发射谱的谱线强度比I391.4/I337.1和振动温度进行了空间分辨测量,发现相同位置处针-水电极放电的谱线强度比要比针-板电极放电的大,并且相同位置处针-水电极放电的振动温度高。 相似文献
5.
在线化学分析需要实现开放环境下的样品取样和电离/激发。相比于激光切削或者激光诱导击穿,大气压微等离子体系统结构简单,更利于小型化。因而基于大气压微等离子体的在线化学分析技术引起行业的广泛关注。为了确定合适的微等离子体源进行样品的在线元素检测,需要进一步了解各放电模式及工作参数下微等离子体的自身特性以及取样效果。该工作主要研究了电弧及辉光放电微等离子体在大气压下对样品铁取样发射光谱的特性。实现了在开放环境下对高熔点金属样品的在线检测,并发现电弧放电微等离子体与光谱分析源联用具有更高的取样效率。高采样效率的电弧放电微等离子体源为实现金属及难解离样品的检测提供了一种新的方法。同时,相较于传统的取样装置,避免了复杂的样品制备、样品传输过程。实验装置采取简单的针对板放电结构,分别利用高压脉冲电源、直流电源获得电弧放电和辉光放电。实验的结果表明,在放电功率近似相等的条件下,电弧放电产生的微等离子体对样品铁取样的光学发射谱中,样品元素的特征谱线占据主导地位,同时伴随有空气中氮气的谱线,而且铁离子(FeⅡ)谱线的相对强度显著高于氮气分子谱线的相对强度。而在直流辉光放电中,样品铁原子(FeⅠ)谱线相对强度非常不明显。由此说明,电弧放电产生的微等离子体具有更高的采样效率。放电在样品表面留下的溅射坑也得出了相同的结论。增加辉光放电电流到25 mA,发现样品元素铁的谱线仍然没有明显的增强。同时,也研究了采样间距对两种采样模式的影响。实验结果表明,间距对两种模式的采样光谱没有显著的影响。采用主要成分为铝的合金铝箔进行了上述对比实验,得出相同的结论,即电弧放电微等离子体更适合作为光谱分析源来实现对金属样品的实时快速检测。 相似文献
6.
Depth profile analysis of the Cu-Ni interdiffusion couple was made by GDOS. Calibration of both the signal intensity and the sputtering rate was used for quantification. The quantified GDOS depth profile was compared with the profile measured by Auger analysis of the bottoms of glow discharge erosion craters with different depths. A reasonable agreement was found between both profiles demonstrating the usefulness of GDOS for this kind of analysis. 相似文献
7.
A. Urbanowicz A. Bielski D. Lisak R. Ciuryło R. S. Trawiński 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(1):1-6
The influence of temperature on the shape
of the self-broadened 748.8 nm
Ne line emitted from the low pressure glow discharge of neon
was investigated with a Fabry-Perot interferometer.
Detailed analysis showed departures of the registered line shapes
from the ordinary Voigt profile.
These departures were consistent with fits of the speed-dependent asymmetric Voigt profile to experimental profiles.
The values of the pressure broadening, shifting and collision-time
asymmetry were determined and compared with those calculated in the adiabatic
approximation for the van der Waals and Lennard-Jones potentials. 相似文献
8.
V. A. Khvostikov S. S. Grazhulene Zh. P. Burmii V. A. Marchenko 《Journal of Applied Spectroscopy》2011,78(5):698-704
Processes in the gas phase of a glow discharge during diode and magnetron reactive sputtering of vanadium in an Ar–O2 atmosphere have been investigated by laser-induced fluorescence (LIF) as a function of the parameters of the glow discharge
and the composition of the atmosphere. The intensity of the fluorescence spectra increased by 1.5–2.0 orders of magnitude
in the magnetron sputtering process compared with that of diode sputtering. Under continuous sputtering conditions, the dependences
of the intensities and relative compositions of the fluorescence spectra on the discharge parameters (discharge voltage and
current) have been investigated. In pulsed mode of the glow discharge, the dynamics of changes in the spectra have been studied
versus variations in the discharge duration and the lag time for recording the fluorescence signal. The dependence of the
spectral line intensities on the partial pressure of oxygen has been found for vanadium and its oxide. The cathode surface
at pressures of 0.03–0.04 Pa was shown to convert to the oxidized state. 相似文献
9.
This experimental investigation shows that the replacement of the spectral line intensity by the optogalvanic and photoelectric optogalvanic signals improves the accuracy of the classical direct layer-by-layer analysis in a hollow cathode glow discharge and its possibilities, for example for layer thickness measurements in some cases. 相似文献
10.
Results of a Doppler spectroscopy study of hydrogen and deuterium
Balmer lines in the stainless steel and copper hollow cathode glow
discharge, operated in pure hydrogen, deuterium and mixtures of inert gases
with hydrogen, are reported. For all gases and gas mixtures plasma
observations perpendicular to electric field revealed the excessively large
Doppler broadening. By changing mode of glow discharge operation, the
Doppler broadened line profiles in helium-hydrogen mixture are recorded
parallel to the discharge electric field as well. The excessively broadened
part of the H line profile is shifted towards blue or red
wavelength by changing the direction of electric field vector. The presence
of large excessive Balmer lines broadening in pure hydrogen and in its gas
mixture with neon as well as shifting of the excessively broadened part of
line profile by means of electric field is in contradiction with the
resonance transfer model proposed by Mills et al. in several publications,
see e.g. [IEEE Trans. Plasma Sci. 31, 338 (2003)]. 相似文献
11.
It is shown that substitution of the spectral line intensity with the photoelectric optogalvanic signal in the hollow-cathode glow discharge enhances the ability for layer-by-layer spectral analysis of surfaces and layers. In particular, this approach improves substantially the thin-film thickness measurements and analysis accuracy. 相似文献
12.
The intensity of Cu-II lines with upper level energies near and above those of the He ion was measured as a function of He pressure in a Cu hollow cathode tube. In this tube at low pressures the negative glow could expand above the cathode. The maximum intensity of the Cu-II 493.1 nm line was found in the low voltage, high pressure hollow cathode discharge region in accordance with a resonant charge transfer excitation process. Enhancement of the intensity of the Cu-II 436.5 nm and 417.9 nm lines was observed in the cathode glow at low pressures. Excitation of these lines is attributed to endoergic charge transfer collisions between He ions accelerated by the 2 kV tube voltage and ground state Cu atoms. The cross-section for this reaction exciting the 436.5 nm line was estimated to be of the order of 10–17 cm2. 相似文献
13.
One-dimensional fluid model of dielectric barrier discharge (DBD) in
helium at atmospheric pressure was established and the discharge was
numerically simulated. It was found that not only the spatial
distributions of the internal parameters such as the electric field,
the electron density and ion density are similar to those in a
low-pressure glow discharge, but also the visually apparent
attribute (light emission) is exactly the same as the observable
feature of a low-pressure glow discharge. This confirms that the
uniform DBD in atmospheric helium is a glow type discharge. The fact
that the thickness of the cathode fall layer is about 0.5mm, much
longer than that of a normal glow discharge in helium at atmospheric
pressure, indicates the discharge being a sub-normal glow discharge
close to normal one. The multipulse phenomenon was reproduced in the
simulation and a much less complicated explanation for this
phenomenon was given. 相似文献
14.
D. Zechev R. Dyulgerova Y. Pacheva 《Journal of Quantitative Spectroscopy & Radiative Transfer》1975,15(10):941-944
The profile of the Fe 372·00 nm line emitted in the negative glow of a hollow-cathode discharge is analyzed. The value of the discharge current was varied within the range 7–15 mA, the neon pressure being 1·22–4·40 Torr. The Lorenzian and Gaussian components of the recorded line profile were corrected for instrumental broadening. A correlation was found to exist between the Gaussian component and the cathode voltage drop. The half-width of the Lorentzian component shows the expected dependence on gas pressure. Under the operating conditions used, this component is approx. 102 times greater than the natural one. No dependence on the discharge current was observed. The emitted line profiles may be considered to be Voigt functions with the Voigt parameter varying in the range 3·2 × 10-2 to 5.5 × 10-2 相似文献
15.
A.?Urbanowicz A.?Bielski D.?Lisak R.?Ciury?o R. S.?Trawiński 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):17-25
Using an interferometric method, detailed analysis
of the self-broadened 748.8 nm Ne line shapes emitted from the glow discharge of neon
was performed, where departures from the ordinary Voigt profile were observed.
These departures are
shown to be consistent with fits of the speed-dependent asymmetric Voigt profile to experimental profiles.
It was shown that neglecting the correlation between Doppler and collisional broadening
may cause errors in determined line shape parameter values.
Coefficients of the pressure broadening, shift and collision-time
asymmetry are determined and compared with those calculated in the adiabatic
approximation for the van der Waals and Lennard-Jones potentials. 相似文献
16.
For an argon glow discharge in a 1 mm thick cell at room temperature, we have observed the absorption spectrum of the 1s3–2p2 (Paschen notation) line by using a diode laser. It is found that, with a decrease in the gas pressure below 0.1 Torr, the linewidth drastically decreases; at 0.02 Torr the velocity distribution of the metastable atoms in the surface normal direction has an apparent temperature of 144 K. The velocity distribution is also found to be anisotropic: the spectrum profile depends on the direction of observation with respect to the surface normal. These phenomena are explained by a model in which the velocity distribution of the metastable atoms is controlled by collisional quenching at the wall surface and velocity-changing collisions with ground state atoms. 相似文献
17.
We demonstrate, for the first time to our knowledge, the utility of coherent Rayleigh scattering (CRS) for temperature measurements in low-density gases and weakly ionized plasmas by measuring the translational temperature of neutral argon in a glow discharge. By analysis of the near-Gaussian spectral profile of the CRS signal, we determine temperatures with an uncertainty of =3%. We also investigate the intensity range over which this simple Gaussian analysis can be used for temperature measurements and discuss its potential for gas diagnostics. 相似文献
18.
The positive column of argon‐oxygen direct current (DC) glow discharge was investigated using a fluid model at pressures of around 410 Pa and discharge currents from 10 to 40 mA. The model was used to study the influence of an oxygen admixture on the properties of argon discharge. The simulated intensity of the electric field strength was compared with measured values at 5% and 100% of oxygen concentration. The one‐dimensional model in a cylindrical tube is based on the drift‐diffusion approximation of particle flux and the mean‐electron‐energy approximation is used to describe the electron interaction. The model takes into account the radial profile of particle concentration, the neutral gas kinetic temperature profile, and interactions with the wall in the cylindrical glass discharge tube. It was shown that 2% of the oxygen admixture causes a significant increase in longitudinal electric field strength and gas heating. 相似文献
19.
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