نتایج جستجو برای: krypton
تعداد نتایج: 1003 فیلتر نتایج به سال:
Element 36 takes its name from the Greek word, kryptos meaning hidden. Like all other members of group 18 (the noble gases), it is colourless, odourless, and occurs in only minute amounts in the Earth’s atmosphere (1.14 ppm in dry air). It was Sir William Ramsay who, following the 1894 discovery of argon with Lord Rayleigh, suggested that a new family of elements would now need to be accommodat...
Manipulation of electron dynamics calls for electromagnetic forces that can be confined to and controlled over sub-femtosecond time intervals. Tailored transients of light fields can provide these forces. We report on the generation of subcycle field transients spanning the infrared, visible, and ultraviolet frequency regimes with a 1.5-octave three-channel optical field synthesizer and their a...
The electron temperature at stagnation of an ICF implosion can be measured from the emission spectrum of high-energy x-rays that pass through the cold material surrounding the hot stagnating core. Here we describe a platform developed on the National Ignition Facility where trace levels of a mid-Z dopant (krypton) are added to the fuel gas of a symcap (symmetry surrogate) implosion to allow for...
The NA48 experiment at CERN[1] aims at making a precision study of direct CP violation in the neutral kaons, by measuring Re (
The first spectra of helium, neon, argon, krypton, and xenon, excited by discharges in Geissler tubes, operated by direct connection to a transformer, have been explored in the infrared (12000 to 19000 A). A high-resolution, automatically recording, infrared spectrometer, employing a 15000-lines-per-inch grating and lead-sulfide photoconducting detector, was used as the dispersing instrument. A...
A novel scheme of coUinear fast beam laser spectroscopy for the detection of the long lived rare isotope *^Kr by observing the optical hyperfme structure spectrum is presented. The technique utilizes cascade two-step excitation to pump metastable krypton atoms to a high-lying Rydberg level. The present work on krypton was motivated by the fact that *̂ Kr is a major tracer gas for exploring the r...
We present results of real-time tracking of atomic two-electron dynamics in an autoionizing transient wave packet in krypton. A coherent superposition of two Fano resonances is excited with a femtosecond extreme-ultraviolet pulse. The evolution of the corresponding wave packet is subsequently probed with a delayed infrared pulse. In our specific case, we get access to the interference between o...
Glass-bonded zeolite is being considered as a candidate ceramic waste form for storing radioactive isotopes separated from spent nuclear fuel in the electrorefining process. To determine the stability of glass-bonded zeolite under irradiation, transmission electron microscope samples were irradiated using high energy helium, lead, and krypton. The major crystalline phase of the waste form, whic...
A series of comparative exposures to both argon and krypton lasers have been made at 3 locations in a human retina--the fovea, the macula, and intraretinal vessels. In the fovea argon irradiations resulted in damage to both the inner and outer retinal layers as a result of absorption within the pigment epithelium and the macular pigment, while krypton exposures damaged the outer retina and the ...
PURPOSE Because of the potential usefulness of evaluating and treating choroidal neovascularization obscured by blood, we designed this study to quantify the transmission of dye fluorescence and laser energy through blood. METHODS Blood preparations anticoagulated with ethylenediaminetetraacetic acid with hematocrits of 0% (plasma), 46%, and 99% were placed in open cuvettes with path lengths ...
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