نتایج جستجو برای: argon

تعداد نتایج: 9143  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2005
O Beeck

As a result of the discovery of Kallmann and Rosent"2 that the probability of charge transfer is very great for gas ions moving in a gas of their own molecular or atomic species, the possibility of obtaining an atomic beam of high intensity is at once indicated. Since the charge transfer itself takes place without altering the translatory energy of the moving ion, the translatory energy of the ...

F. Abbasi Nargesi N. Parvini Ahmadi R. Azari Khosroshahi Azari Khosroshahi

In this research, the high-energy planetary mill was employed to produce nanocrystalline Ti-50Al(γ)(at%) powders. Initial powders were mechanically alloyed in 99.9999% and 90% purities of Argon and also Air atmosphere with alloying times up to 50h. The effect of impurity of Argon atmosphere on the microstructure and the rate of phase transformation of Ti-50Al were investigated during mechanical...

Journal: :journal of modern processes in manufacturing and production 0
javad shahbazi karami faculty of mechanical engineering, shahid rajaee teacher training university, tehran, iran hamed bakhtiarizade department of mechanical engineering, iran university of science &technology, tehran, iran mohsen shahmoradi department of mechanical engineering, maleke-ashtar university of technology, isfahan, iran

development of new technologies and combined with creativity and innovation, plays the fundamental role in developing of any community′s value. thus, in this research the design and production of hydroforming device was introduced. one of the best and most efficient technologies in the world of metal forming is wind turbine blade producing with hydroforming method which seems as an innovative m...

Journal: :The Journal of chemical physics 2011
Fabien Cailliez Pascal Pernot

Calibration of forcefields for molecular simulation should account for the measurement uncertainty of the reference dataset and for the model inadequacy, i.e., the inability of the force-field/simulation pair to reproduce experimental data within their uncertainty range. In all rigour, the resulting uncertainty of calibrated force-field parameters is a source of uncertainty for simulation predi...

Journal: :The Journal of chemical physics 2006
Alexander Fladerer Reinhard Strey

We built a cryogenic nucleation pulse chamber for measuring homogeneous nucleation rates of argon. First measurements show that the growth rate of argon droplets at nucleation conditions is rather high so that nucleation and growth could not yet be decoupled. Nevertheless, the experiments permit an estimate of the onset of nucleation corresponding to a nucleation rate of J=10(7(+/-2)) cm(-3) s(...

Journal: :Physical review letters 2009
Hans Jakob Wörner Hiromichi Niikura Julien B Bertrand P B Corkum D M Villeneuve

We report detailed measurements of the high-harmonic spectra generated from argon atoms. The spectra exhibit a deep minimum that is shown to be independent of the laser intensity, and is thus a clear measure of the electronic structure of the atom. We show that exact field-free continuum wave functions reproduce the minimum, but plane wave and Coulomb wave functions do not. This remarkable obse...

Journal: :Physical review letters 2011
J K Wahlstrand Y-H Cheng Y-H Chen H M Milchberg

We directly measure the nonlinear optical response in argon and nitrogen in a thin gas target to laser intensities near the ionization threshold. No instantaneous negative nonlinear refractive index is observed, nor is saturation, in contrast with a previous measurement [Opt. Express 17, 13429 (2009)] and calculations [Phys. Rev. Lett. 106, 183902 (2011)]. In addition, we are able to cleanly se...

Journal: :Physical review letters 2010
P Béjot J Kasparian S Henin V Loriot T Vieillard E Hertz O Faucher B Lavorel J-P Wolf

We show that higher-order nonlinear indices (n(4), n(6), n(8), n(10)) provide the main defocusing contribution to self-channeling of ultrashort laser pulses in air and argon at 800 nm, in contrast with the previously accepted mechanism of filamentation where plasma was considered as the dominant defocusing process. Their consideration allows us to reproduce experimentally observed intensities a...

Journal: :Applied optics 2004
Sivanandan S Harilal

Optical emission spectroscopic studies of laser-created argon sparks are carried out. Pulses of 532 nm and 8 ns from a frequency-doubled Nd:YAG laser are used to create an argon spark at 1 atm. Gated photography of 2 ns is used to investigate spark evolution at early times. Electron temperature and density measurements are made from the spectral data. The Stark broadening of emission lines is u...

Journal: :Physical review letters 2007
Ewald Janssens Philipp Gruene Gerard Meijer Ludger Wöste Peter Lievens André Fielicke

We report on an element-dependent critical size for argon physisorption at 80 K on transition-metal-doped silicon clusters. Argon does not attach to elemental silicon clusters but only to surface-located transition-metal atoms. Thus physisorption provides structural information. Specifically, the minimal cluster size for the formation of endohedral singly metal-doped silicon cages has been dete...

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