Laser snow

This process was reported for the first time by Tam and Mapper (1). Using the lines of an argon ion laser they photoexcited the cesium atoms to the 7P state through the broadened 6S-7P lines and observed the formation of macroscopic crystals of cesium hydride ("laser snow"). More recently Picqu and coworkers ( ) have reported the same observation using a tunable dye laser resonant with each of the fine structure components of the 6S-7P transition. 

Fluorescence excitation of CO in comets. Comparison with intensities observed for comet West 1976 VI N2 laser excitation of CS2. Fluorescence assigned to progressions from initially excited CS2(T A2) superimposed on continuum arising from collisional (and possibly intramolecular) relaxation Fluorescence spectra of jet-cooled CS2(V B2-X Laser snow in CS2 resulting from excitation at 337, 351, and 357 nm... 

Threshold energy for formation of HD + CDjBr Crossed-beam study of K + HF as a function of rotational state and translational energy Photoreactions leading to the production of laser snow studied in crossed-beam apparatus Study of CsH formation... 

Reaction 16 was first laser induced by Happer and co-workers in a cell experiment under a multi-collision regime, which allowed, spectacularly, the product CsH to condense as powder, the so-called laser snow [144]. The dynamic picture of this reaction has emerged from a series of studies by Vetter and co-workers using a crossed-beam machine where cesium was excited to both the levels 6d [145] and 7p P [146-150]. The most interesting result concerns the reaction dynamics of cesium in the (7p Pi/2) level, which was interpreted after ah initio potential energy surface, semi-classical and quantal dynamics calculations [151 153]. The reaction of cesium in the 8p P and 9p P Rydberg levels with hydrogen molecules has also been studied [154]. 

This last mechanism could explain the nucleation of CsH molecules giving rise to laser snow" formation [3]. 

Laser communication systems based on free-space propagation through the atmosphere suffer drawbacks because of factors like atmospheric turbulence and attenuation by rain, snow, haze, or fog. Nevertheless, free-space laser communication systems were developed for many appHcations (89—91). They employ separate components, such as lasers, modulators, collimators, and detectors. Some of the most promising appHcations are for space communications, because the problems of turbulence and opacity in the atmosphere are absent. 

Neu, T. R. 2000. In situ cell and glycoconjugate distribution in river snow studied by confocal laser scanning microscopy. Aquatic Microbial Ecology 21 85-95. 

Holloway C. F. and Cowen J. P. (1997) Development of a scanning confocal laser microscopic technique to examine the structure and composition of marine snow. Limnol. Oceanogr. 42, 1340-1352. 

M. A. Bolshov, C. F. Boutron, Determination of heavy metals in polar snow and ice by laser-excited atomic fluorescence spectrometry, Analusis Magazine, 22 (1994), M44-M46. 

The network of 211 weather stations allows measurement of tens of basic weather parameters, the most important of which include air temperature, atmospheric pressure, air humidity, wind speed and wind direction. Among the other parameters measured are cloud base height (laser-measured), amount of precipitation (rain or snow), visibility, and air temperature near the ground. Measurements are performed in enclosed areas within the weather stations. 

QIAN S-X., SNOW, J.B., TZENG, H-M. CHANG, R.K. 1986. Lasing droplets Highlighting the liquid-air interface by laser emission. Science 231, 486-488. RAYLEIGH, LORD 1894. The Theory of Sound, vol. II, 2nd edn. London Macmillan. (Reprinted 1945, New York Dover.)... 

Snow-flakes-effect of flat B12 We have learned that boron icosahedra flat out as soon as they are no more embedded in the lattice a-boron. Therefore, we can imagine by laser ablasion, that these unleashed icosahedra release some energy and flat out appraoching the ground state... 

Van Breemen, R.B., Snow, M., Cotter, R.J. (1983) Time-resolved Laser Desorption Mass Spectrometry. 1. Desorption of Preformed Ions. Int. J. Mass Spectrom. Ion Phys. 

Sno84] Snow, D.B., Structure and Mechanical Properties of Laser-Consolidated Ti-6A1-4V and Ti-6Al-2Sn-4Zr-6Mo with Rare Earth Element Additions, in Laser Processing of Materials, K Mukheijee and J. Mazumder, Ed., The MetaUurgical Society, 1984, p. 83-89... 

Qian SX, Snow JB, Chang RK in Laser Spectroscopy V1I(1985) p. 204Hanseh TW, Sho- VR (ed) Springer-Verlag, Berlin Heidelberg New York. 

Baiocchi, C., Giacosa, D., Saini, G., and Cavalli, P. (1994). Determination of thallium in Antarctica snow by means of laser induced atomic fluorescence and high resolution inductively coupled plasma mass spectrometry. Int.J. Environ. Anal. Chem. 55(1 //4), 211. 

The properties of the CO2 snow-jetted substrates were similar, but TCP was the only substrate that proved capable of meeting the requirements of DVS standard 2811. it is also important to choose suitable laser parameters. With the other materials tested there were local roughness peaks that resulted in a reduction in bond surface and, as a result, wire pull-off. 

Heat-assisted die embossing and CO2 snow jetting are smoothing processes that can be applied to reduce roughness. Plating with average roughness < 10 pm can also be produced on laser direct structured MID. [185]... 

O. Wingenter, J. Snow, B. Heikes, and D. Ehhalt (2003), Tunable diode laser measurements of formaldehyde during the TOPSE 2000 study Distributions, trends, and model comparisons, J. Geophys. Res., 108, 8365, doi 10.1029/2002JD002208. 

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