1,538 research outputs found
Cw ion lasers pumped by electron beams
No full textWe have obtained cw laser radiation from singly ionized Hg, I, Cd, Se, and As by exciting He metal-vapor mixtures with a dc electron beam. The beam is generated by glow discharge electron guns located apart from the active medium. This is the first time that cw ion laser action has been obtained using electron beam excitation
CW laser action in atomic fluorine
No full textWe have obtained CW laser action on four transitions in the doublet system of atomic fluorine for the first time. All previously reported laser action was on a pulsed basis only. CW laser radiation was obtained when F2 or AgF was used as a fluorine donor in an electron beam pumped helium plasma. A multiline output power of 200 mW was obtained
Plasmodium infection, anaemia and mosquito net use among school children across different settings in Kenya.
No full textOBJECTIVE: To investigate risk factors, including reported net use, for Plasmodium infection and anaemia among school children and to explore variations in effects across different malaria ecologies occurring in Kenya. METHODS: This study analysed data for 49 975 school children in 480 schools surveyed during a national school malaria survey, 2008-2010. Mixed effects logistic regression was used to investigate factors associated with Plasmodium infection and anaemia within different malaria transmission zones. RESULTS: Insecticide-treated net (ITN) use was associated with reduction in the odds of Plasmodium infection in coastal and western highlands epidemic zones and among boys in the lakeside high transmission zone. Other risk factors for Plasmodium infection and for anaemia also varied by zone. Plasmodium infection was negatively associated with increasing socio-economic status in all transmission settings, except in the semi-arid north-east zone. Plasmodium infection was a risk factor for anaemia in lakeside high transmission, western highlands epidemic and central low-risk zones, whereas ITN use was only associated with lower levels of anaemia in coastal and central zones and among boys in the lakeside high transmission zone. CONCLUSIONS: The risk factors for Plasmodium infection and anaemia, including the protective associations with ITN use, vary according to malaria transmission settings in Kenya, and future efforts to control malaria and anaemia should take into account such heterogeneities among school children
CW silver ion laser with electron beam excitation
No full textA CW laser power of 140 mW was obtained in the 840.39 nm transition of Ag II by electron beam excitation. This electron beam excited metal vapor ion laser is capable of operating using metals with high vaporization temperatures and is of interest for generation of CW coherent radiation in the 220-260 nm spectral region
1-W cw Zn ion laser
No full textWe have obtained 1.2W of cw laser power on the 4911.6- and 4924.0-Å transitions of Zn II by exciting a He-Zn gas mixture with a dc glow discharge electron beam. In addition, 0.25-W output power has been obtained on the 6149.9-Å line of Hg+ using the same excitation scheme. The combination of electron beam ionization of rare gas atoms and subsequent charge transfer excitation to metal ion levels is shown to have the potential of significantly increasing the efficiency of ion lasers. cw multiwatt visible and ultraviolet ion lasers operating at efficiencies > 10-3 appear feasible using this excitation scheme
Stabilization as a CW approximation
No full textAbstractThis paper describes a peculiar property of the category of S-modules constructed by the author, Kriz, Mandell, and May: the full subcategory of suspension spectra (all of which are S-modules) forms a precise copy of the category of topological spaces. Consequently, the “classical” homotopy category of S-modules with morphisms the actual homotopy classes of maps contains a copy of unstable homotopy theory. Stabilization and stable homotopy are induced by CW approximation as S-modules. One consequence is that CW complexes whose suspension spectra are CW S-modules must be contractible
Cw iodine ion laser excited by an electron beam
No full textCW laser oscillation has been obtained on the 5760.7 and6127.5 Å transitions of singly ionized iodine in an He-I2 plasma excited by a dc electron beam
A closed manifold is a fat CW complex
No full textIn this paper, we introduce a notion of a fat CW complex to show that a
closed manifold is a regular CW complex, while it is not always the case if we
discuss about a smooth CW structure, introduced by the first author, instead of
a fat CW structure. We also verify that de Rham theorem holds for a fat CW
complex and that a regular CW complex is reflexive in the sense of Y.~Karshon,
J.~Watts and P.~I-Zemmour. Further, any topological CW complex is topologically
homotopy equivalent to a fat CW complex. It implies that there are lots of
non-manifold examples supporting de Rham theorem.Comment: 17 page
Electron beam pumped cw Se II laser
No full textWe have observed cw laser action in 15 transitions of singly ionized selenium using an electron beam to excite a He-Se mixture. The variation of the laser output power as a function of the electron beam discharge parameters is reported
Cw laser oscillations in Cd II in an electron beam created plasma
No full textA cw Cd II laser has been demonstrated using electron beam excitation. Cw laser oscillation has been obtained on six transitions of Cd 11 in a He-Cd plasma. Output power as a function of electron beam discharge parameters has been investigated
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