Search results for "Time duration"
showing 3 items of 3 documents
Parametric Frequency Conversion of Short Optical Pulses Controlled by a CW Background
2007
International audience; We predict that parametric sum-frequency generation of an ultra-short pulse may result from the mixing of an ultra-short optical pulse with a quasi-continuous wave control. We analytically show that the intensity, time duration and group velocity of the generated idler pulse may be controlled in a stable manner by adjusting the intensity level of the background pump.
Structural properties of the range-II- and range-III order in amorphous-SiO2 probed by electron paramagnetic resonance and Raman spectroscopy
2010
In the present work we report an experimental investigation by electron paramagnetic resonance spectroscopy on the hyperfine structure of the E. point defect, probing the local arrangement of the network (range-II order), and by Raman spectroscopy on the D 1 and D 2 lines, probing mean features of the network (range-III order). Our studies, performed on a-SiO 2 samples thermally treated at 1000 °C in air for different time durations, show that changes of the hyperfine structure and of the D 1 and D 2 lines occur in a correlated way. These results give strong evidence that the range-II and range-III order properties are intimately related to each other and that these properties are determine…
MIGRATION OF THE HIGHLY EDUCATED: EVIDENCE FROM RESIDENCE SPELLS OF UNIVERSITY GRADUATES*
2011
We examine the inter-regional migration of university graduates from 1991 to 2003 in Finland. The results show that time matters: two-years before and during the graduation year the hazard rates of migration increase, and then decrease thereafter. Although university graduates are particularly mobile, we find that most of them do not move from their region of studies within 10 years after graduation. The out-migration, i.e., brain drain, is much higher among graduates in the more peripheral universities than in the growth centers (Helsinki in particular). Migration is also substantially more likely for those studying away from the home region than for those studying at home. peerReviewed