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61.
J.S. Becker R.C. Dietrich A. Matusch D. Pozebon V.L. Dressler 《Spectrochimica Acta Part B: Atomic Spectroscopy》2008
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for quantitative imaging of toxic and essential elements in thin sections (thickness of 30 or 40 μm) of tobacco plant tissues. Two-dimensional images of Mg, Fe, Mn, Zn, Cu, Cd, Rh, Pt and Pb in leaves, shoots and roots of tobacco were produced. Sections of the plant tissues (fixed onto glass slides) were scanned by a focused beam of a Nd:YAG laser in a laser ablation chamber. The ablated material was transported with argon as carrier gas to the ICP ion source at a quadrupole ICP-MS instrument. Ion intensities of the investigated elements were measured together with 13C+, 33S+ and 34S+ within the entire plant tissue section. Matrix matching standards (prepared using powder of dried tobacco leaves) were used to constitute calibration curves, whereas the regression coefficient of the attained calibration curves was typically 0.99. The variability of LA-ICP-MS process, sample heterogeneity and water content in the sample were corrected by using 13C+ as internal standard. Quantitative imaging of the selected elements revealed their inhomogeneous distribution in leaves, shoots and roots. 相似文献
62.
V. I. Nasonov 《Journal of Applied Spectroscopy》2006,73(2):234-244
Radiation scattering by particles of condensed phase in an ablation plasma plume has been experimentally studied during quasicontinuous
laser irradiation (λ = 1.06 μm, q = 0.1–9 MW/cm2, τ ∼ 1.5 msec) of duraluminum D16T, aluminum A99, and bismuth. The particle size distribution and the nature of their dispersal
during irradiation was studied in scattered light (λ = 0.69 μm) from individual particles that could be visually observed
on photographs. It was found that under the pressure developed in the plume, large particles ejected from the irradiated zone
can move backward and return to the target (D16T). The plume (Bi) becomes brighter due to ablation of particles in the path
of the laser beam. The directional scattering coefficients for scattering from the local zone on the axis of the plume, measured
during the laser pulse, were used to study the relationship between the dynamics of entry of condensed phase into the plume,
shielding of the target by the particles, and brightening of the plume under the action of the incident laser radiation.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 210–219, March–April, 2006. 相似文献
63.
The paper describes past and present efforts in modeling of laser-induced plasma and overviews plasma diagnostics carried out by pump-probe techniques. Besides general information on existing plasma models, the emphasis is given to models relevant to spectrochemical analysis, i.e. models of radiating plasma. Special attention is paid to collisional-radiative (CR) and collisional-dominated (CD) plasma models where radiative processes play an important role. Also, calibration-free (CF) models are considered which may endow with the possibility for standardless spectroscopic analysis. In the diagnostic part, only methods based on the use of additional diagnostic tools (auxiliary lasers, optics, and probes) are described omitting those based on plasma own radiation. A short review is provided on image-based diagnostics (shadowgraphy, schlieren, and interferometry), absorption and fluorescence, Langmuir probe, and less frequently used cavity ringdown and Thomson scattering methods. 相似文献
64.
脉冲激光烧蚀金属平面铝靶产生的热原子与气相CF4碰撞反应中,在400—600nm之间观测到激发态C2分子的发光光谱,它们可归属为Swan带的d3Πg-a3Πu跃迁中Δv=2,1,0,-1,-2五个振动序列(v'≤6).光谱强度分析表明,C2激发态的振动温度达6340K左右.与激光烧蚀Al+O2反应生成AlO的实验结果以及激光烧蚀Cu+CF4的光谱比较,对比Al(2P1/2-2S1/2,3944nm)和C2的d—a跃迁(0—0)带带头(5165nm)的飞行时间轮廓,认为激发态的Al(2S1/2)原子通过
关键词:
激光烧蚀
发光光谱
C2分子 相似文献
65.
L. Torrisi A.M. Mezzasalma J. Badziak J. Wolowski G. Franco 《Applied Surface Science》2006,252(24):8533-8538
High energy laser plasma-produced Cu ions have been implanted in silicon substrates placed at different distances and angles with respect to the normal to the surface of the ablated target. The implanted samples have been produced using the iodine high power Prague Asterix Laser System (PALS) using 438 nm wavelength irradiating in vacuum a Cu target. The high laser pulse energy (up to 230 J) and the short pulse duration (400 ps) produced a non-equilibrium plasma expanding mainly along the normal to the Cu target surface. Time-of-flight (TOF) technique was employed, through an electrostatic ion energy analyzer (IEA) placed along the target normal, in order to measure the ion energy, the ion charge state, the energy distribution and the charge state distribution. Ions had a Boltzmann energy distributions with an energy increasing with the charge state. At a laser fluence of the order of 6 × 106 J/cm2, the maximum ion energy was about 600 keV and the maximum charge state was about 27+.In order to investigate the implantation processes, Cu depth profiles have been performed with Rutherford backscattering spectrometry (RBS) of 1.5 MeV helium ions, Auger electron spectroscopy (AES) with 3 keV electron beam and 1 keV Ar sputtering ions in combination with scanning electron microscopy (SEM). Surface analysis results indicate that Cu ions are implanted within the first surface layers and that the ion penetration ranges are in agreement with the ion energy measured with IEA analysis. 相似文献
66.
The influence of pulse duration on the stress levels in ablation of ceramics: A finite element study
A. Vila Verde 《Applied Surface Science》2006,252(13):4511-4515
We present a finite element model to investigate the dynamic thermal and mechanical response of ceramic materials to pulsed infrared radiation. The model was applied to the specific problem of determining the influence of the pulse duration on the stress levels reached in human dental enamel irradiated by a CO2 laser at 10.6 μm with pulse durations between 0.1 and 100 μs and sub-ablative fluence. Our results indicate that short pulses with durations much larger than the characteristic acoustic relaxation time of the material can still cause high stress transients at the irradiated site, and indicate that pulse durations of the order of 10 μs may be more adequate both for enamel surface modification and for ablation than pulse durations up to 1 μs. The model presented here can easily be modified to investigate the dynamic response of ceramic materials to mid-infrared radiation and help determine optimal pulse durations for specific procedures. 相似文献
67.
In this study,right-handed dicinnamate isosorbide was synthesized via the esterification reaction between optically active isosorbide and cinnamate.The chiral dopant was characterized by FT-IR,~1H NMR,elemental analysis,SEM,UV absorption spectrum.After dissolving in a nematic liquid crystal mixture,the chiral dopant exhibited a temperature-dependent solubility in the chiral nematic liquid crystal mixture.Meanwhile,a relatively high value of helical twisting power of the polymerizable chiral dopant was de... 相似文献
68.
Ying-Tung Chen Kris Naessens Roel Baets Yunn-Shiuan Liao Ampere A. Tseng 《Optical Review》2005,12(6):427-441
For many years, the development of effective ablation or laser machining techniques for making micro-optical components has
been the key factor in the birth of new photonic devices and systems. In this article, the ablation characteristics of two
types of the most important transparent materials, transparent polymers and glasses, are studied. Simple shaped microcavities
are first machined for studying the fundamental ablation parameters, including threshold fluence, effective absorption coefficient,
and ablation rate. In studying polymer ablation, five standard grades and five proprietary polymeric compounds are selected.
Ablation techniques using these transparent polymers for making arrayed ferrules and curved microlenses are presented. Applications
of these ablated microstructures for optical fiber connectors, optical fiber coupling and alignment, and transparent chip
encapsulants, are introduced and demonstrated with emphasis on the quality of the ablated profiles and dimensions to satisfy
the required performance. In glass ablation, borosilicate glasses are considered and their associated ablation behaviors are
studied. The procedures to ablate glass-based arrayed microstructures with flat and curved surfaces are described. The utilizations
of these arrayed microstructures for optical waveguide, wave absorber, and beam guider, are specifically discussed. Finally,
concluding remakes for future trends are presented. 相似文献
69.
70.
In this paper, experimental results of the investigation of the periodic structure on thermoelectric semiconductor Cu2Se are presented. Periodic structures were formed on surfaces of semiconductors due to multi-beam interaction of Q-switched Nd:YAG laser, which was operated in the lowest order of Gaussian mode and pulse duration 7 ns. Surface temperature evolution and transient reflectivity are studied during laser treatment. Creation of Cu islands in the maximal intensity of interference pattern was found. 相似文献