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The influence of depletable amplification, group velocity dispersion and self-phase modulation due to Kerr-type nonlinearity on pulse shaping in femtosecond pulse amplification has been calculated. With gain depletion which is typical for the last stage of multi-stage amplifiers, spectral broadening occurs which, under certain conditions, can be utilized for pulse compression. This spectral broadening as well as a predicted spectral shift is compared with experimental results. 相似文献
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A host-guest optical sensor for the determination of aliphatic amines as exemplified by octylamine is proposed. It is based on the reversible fluorescence enhancement of heptakis(2,6-di-O-isobutyl)-β-cyclodextrin(DOB-β-CD) hosting tetraphenylporphyrin (TPP) immobilized in poly(vinyl chloride) (PVC) membrane by aliphatic amine extracted from aqueous phase into membrane phase. The optimum membrane contained 1.15 wt % TPP, 6.15 wt % DOB-β-CD as sensing reagent and other membrane materials. The fluorescence enhancement of the membrane resulted from the formation of a stable three-component complex among DOB-β-CD, TPP, and aliphatic amines. With the optimum conditions described, the fluorescence response of the sensor to octylamine shows a good correlation with the theoretically derived equation in the range 1.0 × 10–6 to 8.0 × 10–4 mol/L. The response characteristics including reversibility, response time, reproducibility and lifetime and selectivity of this optical device are also discussed in detail. This sensor has also been applied for the determination of octylamine in water samples containing interferents with satisfactory recovery. 相似文献
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Amita Gupta Alexei Yu Ganin Parmanand Sharma Vikrant Agnihotri LM Belova KV Rao Mikhail E Kozlov AA Zakhidov RH Baughman 《Pramana》2002,58(5-6):1051-1059
We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show
a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are
found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there
exists no report in literature on any BiNi compound which is magnetic. 相似文献
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Ohne Zusammenfassung 相似文献
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H.-S. Albrecht P. Heist J. Kleinschmidt D. V. Lap 《Applied physics. B, Lasers and optics》1993,57(3):193-197
We represent an ultrafast beam-deflection method as a simple and powerful tool for the time-resolved measurement of induced changes of the refractive index in the order of n=10–5. The method is applied for measuring the changes of components of the refractive index parallel and perpendicular to the pump-pulse polarization on a femtosecond time scale. Fused silica and CS2 are used as samples for demonstrating our method. 相似文献
7.
H.-St. Albrecht P. Heist J. Kleinschmidt D. van Lap T. Schröder 《Applied physics. B, Lasers and optics》1992,55(4):362-364
We demonstrate the optical Kerr shutter technique as a simple and powerful tool for the measurement of femtosecond pulses in the ultraviolet as well as in the visible spectral region. The method provides the third-order intensity correlation function which gives information about pulse asymmetry and pulse structures. 相似文献
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combined laser-doppler and cold wire anemometry technique for determining turbulent heat flux is described. The system can
be used in flows of arbitrarily high turbulent intensity and large temperature variations. Its potential is demonstrated via
measurements in a simulated stable atmospheric boundary layer, for which the Monin-Obukhov length scale was about 70% of the
boundary layer depth. Mean and turbulence properties were obtained throughout the boundary layer and the results are shown
to be both internally consistent and similar to corresponding field data. Measurements in the highly turbulent, separated
flow behind a bluff body mounted in the stable boundary layer are also presented.
Received: 9 May 1997 / Accepted: 2 September 1997 相似文献
9.
A host-guest optical sensor for the determination of aliphatic amines as exemplified by octylamine is proposed. It is based
on the reversible fluorescence enhancement of heptakis(2,6-di-O-isobutyl)-β-cyclodextrin(DOB-β-CD) hosting tetraphenylporphyrin
(TPP) immobilized in poly(vinyl chloride) (PVC) membrane by aliphatic amine extracted from aqueous phase into membrane phase.
The optimum membrane contained 1.15 wt % TPP, 6.15 wt % DOB-β-CD as sensing reagent and other membrane materials. The fluorescence
enhancement of the membrane resulted from the formation of a stable three-component complex among DOB-β-CD, TPP, and aliphatic
amines. With the optimum conditions described, the fluorescence response of the sensor to octylamine shows a good correlation
with the theoretically derived equation in the range 1.0 × 10–6 to 8.0 × 10–4 mol/L. The response characteristics including reversibility, response time, reproducibility and lifetime and selectivity
of this optical device are also discussed in detail. This sensor has also been applied for the determination of octylamine
in water samples containing interferents with satisfactory recovery.
Received: 21 November 1999 / Revised: 10 January 2000 / Accepted: 15 January 2000 相似文献
10.
We report on a cavity-dumped Yb:YAG thin disk laser with intracavity-frequency doubling to provide pulses in the millijoule energy range at a repetition rate of up to 100 kHz. The maximum average output power at 515 nm was 102 W with pulses of a pulse length of 300 ns. An additional advantage of the presented laser setup is the wide tunability of the pulse duration. 相似文献