Output power and polarization characteristics for a diode-side-pumped Nd:YAG rod laser with a diffusive optical pump cavity

Introduction: The aim of this study was to test the hypothesis that caffeine supplementation (6 mg·kg-1 body mass) for 4-days, followed by acute intake, would impact five male triathletes output power after performed submaximal intensity exercise. Methods: This was a randomized, double-blind, placebo-controlled crossover study, placebo (4-day) - placebo (acute) PP, placebo (4-days) -caffeine (acute) PC, and caffeine (4-day) - caffeine (acute) CC. Participants abstained from dietary caffeine sources for 4 days and ingested capsules containing either placebo or caffeine (6 mg.kg-1 body mass day in one absorption). The acute trials the capsules containing placebo or caffeine (6 mg.kg-1 body mass day in one absorption) were ingested 60min before completing exercise in a treadmill for 40min (80% VO2max) and to perform the Wingate test. Results: Blood lactate was determined before, 60min after ingestion, and immediately after the exercise on the treadmill, the Wingate test, and after the recovery (10-min). CC and PC trials did not change the cardiopulmonary variables (P>0.05) and the anaerobic power variables (peak/mean power output and fatigue index) (P>0.05). The PC trial compared with PP promoted improvements in the curve power output in 2 sec by 31.19% (large effect-size d = 1.08; P<0.05) and 3 sec by 20% (large effect-size d = 1.19; P<0.05). A 10min recovery was not sufficient to reduce blood lactate concentration in the PC trial compared with PP (PC, 13.73±2.66 vs. PP, 10.26±1.60 mmol.L-1; P<0.05, respectively) (P<0.05). Conclusion: In conclusion, these results indicate that caffeine supplementation (6 mg·kg-1 body mass) for 4 days, followed by acute ingestion, did not impact the triathletes output power after performed submaximal intensity exercise. Nutritional interventions may help researchers and athletes to adapt strategies for manipulating caffeine use.Key-words: caffeine metabolism, Wingate test, blood lactate, performance.

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Design and Analysis of DCJDCZCT Boost Converter with Moderate Output Power

Iraqi Journal for Electrical And Electronic Engineering ◽

10.33762/eeej.2001.55688 ◽

2001 ◽

Vol 1 (1) ◽

pp. 43-58

Author(s):

Mustafa M. Ibrahim ◽

Khalid M. Abdul Hassan

Keyword(s):

Output Power ◽

Boost Converter

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Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

MRS Proceedings ◽

10.1557/proc-770-i3.2 ◽

2003 ◽

Vol 770 ◽

Cited By ~ 1

Author(s):

Nathanael Smith ◽

Max J. Lederer ◽

Marek Samoc ◽

Barry Luther-Davies ◽

Robert G. Elliman

Keyword(s):

Probe Beam ◽

Time Resolution ◽

Pump Beam ◽

Silicon Nanocrystals ◽

Continuous Wave ◽

Optical Gain ◽

Optical Pump ◽

Time Resolved ◽

Pump Probe ◽

Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

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