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961.
Emission spectra of the A2Π3/2-X2Σ+ (0, 1), (0, 0), and (1, 0) bands and the B2Σ+-X2Σ+ (0, 1), (0, 0), (1, 0), (2, 0), and (3, 1) bands of ScS have been recorded in the 10 000-13 500 cm−1 region at a resolution of 0.05 cm−1 using a Fourier transform (FT) spectrometer. The A2Πr-X2Σ+ (1, 0) band as well as the B2Σ+-X2Σ+ (0, 0) and (1, 0) bands have been recorded at high resolution (±0.001 cm−1) by laser excitation spectroscopy using a supersonic molecular beam source. The FT spectral features range up to N = 148, while those recorded with the laser cover the “low-N” regions. The lines recorded with the laser exhibit splittings due to the 45Sc (I = 7/2) magnetic hyperfine interactions, which are large (∼6.65 GHz) in the X2Σ+ state and much smaller in the B2Σ+ and A2Π states. The energy levels were modeled using a traditional ‘effective’ Hamiltonian approach, and improved spectroscopic constants were extracted and compared with previous determinations and theoretical predictions. 相似文献
962.
D. Verney L. Cabaret J. E. Crawford H. T. Duong B. Fricke J. Genevey G. Huber F. Ibrahim M. Krieg F. Le Blanc J. K. P. Lee G. Le Scornet D. Lunney J. Obert J. Oms J. Pinard J. C. Puteaux K. Rashid B. Roussière J. Sauvage V. Sebastian 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):489-518
Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental
setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam
deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant
scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first
transition of the ionization path 5d
76s
24
F
9/2 → 5d
76s6p
6
F
11/2 at 351.5nm were measured for 182-189Ir, 186Ir
m
and the stable 191, 193Ir. The nuclear magnetic moments μI and the spectroscopic quadrupole moments Qs were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of μI was experimentally determined for the first time for the masses 182≤A≤189 and the isomeric state 186Ir
m
. The spectroscopic quadrupole moments of 182Ir and 183Ir were measured also for the first time. A large mean square charge radius change between 187Ir and 186Ir
g
and between 186Ir
m
and 186Ir
g
was observed corresponding to a sudden increase in deformation: from β2 ≃ + 0.16 for the heavier group A = 193, 191, 189, 187 and 186m to β2≥ + 0.2 for the lighter group A = 186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one
or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the
odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified
with the π3/2+[402] orbital for the heavier group and with the π1/2-[541] orbital stemming from the 1h
9/2 spherical subshell for the lighter group. That last state seems to affect strongly the observed values of the nuclear moments. 相似文献
963.
This paper deals with improvements in the measurements of optical power by using CCD-based stabilization optics. Absolute optical power scale has been realized at discrete laser wavelengths of vertically polarized tuneable Ar+, fixed He–Ne and fixed Nd:YAG (with second harmonic) laser sources. Electrical-substitution cryogenic radiometer was operated at the helium temperature for this purpose. To make measurements on the metrological level the intensities of lasers were stabilized to better than 0.004% by using an established system. Using the highly collimated and stabilized lasers, whose beam shape and dimension were adjusted properly, leads us to measure the absolute optical powers with an uncertainty in the order of 10−4. 相似文献
964.
Cobalt-based alloy coatings with and without nano-Y2O3 particles produced by a 5 kW CO2 laser on Ni-based superalloy were introduced. Solidified microstructure, phase compositions and distribution of nano-particles were investigated by using optical microscope, SEM, TEM and XRD. The results showed that metastable phases, such as γ-Co and Cr23C6 existed in cobalt-based alloy coatings. Another two phases (Y2O3 and ?-Co) were found by adding nano-Y2O3. Without nano-Y2O3, rapid directional solidified microstructure of columnar dendrite appeared. Fine and short dendritic microstructure and columnar to equiaxed transition (CET) occurred by adding nano-Y2O3 particles. With the increase in amount of nano-Y2O3, fully equiaxed crystallization appeared and the formation mechanism was analyzed. The results also showed that the sub-microstructure of the coatings changed from dislocation to stacking fault by adding nano-Y2O3. 相似文献
965.
Robert S. Barlow 《Proceedings of the Combustion Institute》2007,31(1):49-75
Laser diagnostics for fundamental investigation of turbulent combustion are discussed in the context of collaborative research that has been conducted over the past decade to contribute toward the development and experimental validation of predictive science-based models for turbulent flames. The emphasis is on simultaneous application of multiple laser techniques in flames having relatively simple fuels and flow geometries, as well as separate application of complementary diagnostics in the same flames. Data needs and design considerations for turbulent combustion model-validation experiments are outlined. Examples are given of ways in which the interplay of experiments and computations on “standard” turbulent flames has led to better understanding of these flames and also a better understanding of the capabilities of laser diagnostics and models to accurately capture the effects of turbulence-chemistry interactions. Issues of spatial resolution, differential diffusion, and LES validation are discussed, and perspectives on current research challenges are offered. 相似文献
966.
本文给出了在UCLA的Microtor装置上,用远红外(FIR)激光散射,对离子回旋共振频率范围(ICRF)的外驱动集体电子密度起伏的测量,并对这些结果进行了分析,发现实验结果直接与两种离子等离子体的快波模转换理论相符合。此外,也描述了本实验所用激光散射系统,简单地讨论了有待进一步探讨的问题。 相似文献
967.
Study of the buckling mechanism in laser tube forming 总被引:1,自引:0,他引:1
The buckling mechanism of a thin metal tube during laser forming was investigated numerically and experimentally in this study. Metal tubes made of 304 stainless steel were heated by a CO2 Gaussian laser beam, which induced the buckling phenomenon on the tube surface due to elastic–plastic deformation. This uncoupled thermal–mechanical problem was solved using a three-dimensional finite element method and was subsequently satisfactorily verified with displacement measurements. The transient bending angle and residual stress of the thin metal tube under specific operation conditions were also studied. 相似文献
968.
激光气化进样等离子体发射光谱测定锡石中微量元素 总被引:3,自引:1,他引:2
采用自动设计、组装的激光气化等离子体发射光谱分析装置,系统地研究了单矿物锡石中21种元素的蒸发、激发特性。将样品全蒸发输入ICP激发,光谱测定,分析结果与经化学分离富集、ICP-AES测定结果吻合。 相似文献
969.
用激光熔出-共振离子化质谱法测定纯铁中及高纯硅片表面的铬。测定含有1012原子/cm2Cr的信号强度表明本方法可测定低至109原子/cm2的样品,其空间分辨率为0.2mm,还可进行二维杂质元素分析。 相似文献
970.
Ar辅助确定Al等离子体电子温度 总被引:4,自引:1,他引:3
用Ar气作保护气时 ,Nd :YAG脉冲激光烧蚀Al靶 ,将诱发Ar气电离 ,并产生丰富的Ar离子谱线辐射。文章根据Ar离子谱线辐射信息 ,分析了ArⅡ 385 0 5 7,ArⅡ 386 85 3,ArⅡ 4 0 4 2 91 ,ArⅡ 4 0 7 2 0 1nm等 4条谱线的时间分辨行为 ,计算了Al等离子体的电子温度。结果发现 :Al等离子体的电子温度约 1 5 0 0 0~2 2 0 0 0K ,随延迟时间的增加 ,电子温度单调衰减 相似文献