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1.
T. Hansel J. Müller C. Falldorf C. von Kopylow W. Jüptner R. Grunwald G. Steinmeyer U. Griebner 《Applied physics. B, Lasers and optics》2007,89(4):513-516
Digital holographic shape measurements using femtosecond laser pulses are reported. For contouring of very fast moving objects,
the simultaneous generation of at least two spectrally separated ultrashort pulses is required. To deliver this particular
spectral signature at high pulse energies, a chirped-pulse Ti:sapphire laser amplifier was modified to emit two spectrally
separated pulses with energies above 1 μJ each. The wavelength separation of these pulses was adjustable within the 50 nm
gain bandwidth, cutting out two distinct wavelength peaks by a variable double-slit assembly in a prism sequence. A Michelson-type
interferometer was employed to perform the two-wavelength contouring. The phases of the holograms and the phase differences
are calculated numerically, which allow us to deduce the contour lines of the topology of the object. The suitability of the
light source for digital holography is demonstrated with contouring of stationary objects and the potential for high-speed
applications is indicated.
PACS 42.40.-i; 42.60.By 相似文献
2.
An expression for the heat conductivity
xx
is derived in the effective medium approximation. Mott type formulas are obtained for
xx
and the Peltier coefficient
xx
. Using percolation theory in a three-dimensional system the Wiedemann-Franz ratio was found to depend on the temperature like
. The Mott type formulas were evaluated in a similar way for a two-dimensional system in the quantum Hall regime within the high-field percolation model. In contrast to previous calculations of the high field hopping conductivity
xx
, the results are fully consistent with the experimental data on
xx
and the density of states at the Fermi level. Finally,
xx
is estimated which together with
xx
and
xy
=ie
2/h(i=0,1,2,...), determines both thermopower coefficients
xx
and
xy
.Dedicated to Professor W. Brenig on the occasion of his 60th birthday 相似文献
3.
4.
Peter Grunwald 《Nachrichten aus der Chemie》1995,43(12):1292-1297
5.
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7.
Flashlamp-pumped high-gain fiber-bundle lasers consisting of multimode phosphate glass fibers have been investigated. By optimizing the fiber number and the outcoupling reflectivity in dependence on the pump conditions, high single-pulse energies in excess of 1 J as well as high-average-power extraction up to 100 W at a pulse repetition frequency of 100 Hz could be obtained from slim fiber-bundle lasers. Fiber numbers in the range of 150–250 and reflectivities between 35% and 50% have been found to provide reliable performance. 相似文献
8.
9.
The reaction of lanthanum with hydrogen was investigated in the temperature region 100°C to 800°C. The predominant portion of the hydrogen is taken up at constant rate. The final saturation with hydrogen is diffusion-controlled and obeys the parabolic-laws. 相似文献
10.
Samuel Jorice Raccurt Olivier Poncelet Olivier Auger Aurélien Ling Wai-Li Cherns Peter Grunwald Didier Tillement Olivier 《Journal of nanoparticle research》2010,12(6):2255-2265
Journal of Nanoparticle Research - Fluorescent silica nanoparticles are widely used for various applications from mechanical reinforcement to biology. In many cases, their surface has to be... 相似文献