We determine the absolute frequencies of 56 rotation-vibration transitions of the ν(3) band of CH(4) from 88.2 to 90.5 THz with a typical uncertainty of 2 kHz corresponding to a relative uncertainty of 2.2 × 10(-11) over an average time of a few hundred seconds. Saturated absorption lines are observed using a difference-frequency-generation source and a cavity-enhanced absorption cell, and the transition frequencies are measured with a fiber-laser-based optical frequency comb referenced to a rubidium atomic clock linked to the international atomic time. The determined value of the P(7) F(2)((2)) line is consistent with the International Committee for Weights and Measures recommendation within the uncertainty.
A liquid jet injector is a biomedical device intended for drug delivery. Medication is delivered through a fluid stream that penetrates the skin. This small diameter liquid stream is created by a piston forcing a fluid column through a nozzle. These devices can be powered by springs or compressed gas. In this study, a CFD simulation is carried out to investigate the fluid mechanics and performance of needle free injectors powered specifically by compressed air. The motion of the internal mechanisms of the injector which propels a liquid jet through an orifice is simulated by the moving boundary method and the fluid dynamics is modeled using LES/VOF techniques. In this paper, numerical results are discussed by comparing the fluid stagnation pressures of the liquid jet with previously published experimental measurements obtained using a custom-built prototype of the air-powered needle free liquid injector. Performance plots as a function of various injector parameters are presented and explained.
We have developed a measurement method for obtaining spatial
distributions of absolute densities of CF and CF2 radicals in a plasma
reactor by combining single-path infrared laser absorption spectroscopy
(IRLAS) and laser-induced fluorescence (LIF) techniques. This novel method
has been successfully applied to the spatial distribution measurement
of absolute densities of CF and CF2 radicals in an electron cyclotron
resonance (ECR) plasma reactor employing a tetrafluorocarbon gas
(C4F8). It was found that CF radical densities were higher
than CF2 ones in the plasma region but lower outside the plasma region.
The work functions of ZrO/W(100) and YO/W(100) surfaces are investigated by the ab initio calculation based on the density-functional theory. The work function of the W(100) surface is markedly decreased owing to the adlayers of ZrO and YO, which is in good agreement with experimental observations. The energetically stable configuration of ZrO and YO on the W(100) surface is found not to be perpendicular to the surface but to lie on the surface, which cannot be derived from the phenomenological surface-dipole model. We found from the detailed analysis of surface electronic structures that the lying configuration lowers the work function appreciably, particularly for ZrO, owing to an O atom going into the hollow site of the W(100) surface. The present study emphasizes the crucial role of ab initio calculation for clarifying the electronic-state-based origin of the work function.
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