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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.
3.
Optical sensor systems for bioprocess monitoring 总被引:3,自引:0,他引:3
Bioreactors are closed systems in which microorganisms can be cultivated under defined, controllable conditions that can be optimized with regard to viability, reproducibility, and product-oriented productivity. To drive the biochemical reaction network of the biological system through the desired reaction optimally, the complex interactions of the overall system must be understood and controlled. Optical sensors which encompass all analytical methods based on interactions of light with matter are efficient tools to obtain this information. Optical sensors generally offer the advantages of noninvasive, nondestructive, continuous, and simultaneous multianalyte monitoring. However, at this time, no general optical detection system has been developed. Since modern bioprocesses are extremely complex and differ from process to process (e.g., fungal antibiotic production versus mammalian cell cultivation), appropriate analytical systems must be set up from different basic modules, designed to meet the special demands of each particular process. In this minireview, some new applications in bioprocess monitoring of the following optical sensing principles will be discussed: UV spectroscopy, IR spectroscopy, Raman spectroscopy, fluorescence spectroscopy, pulsed terahertz spectroscopy (PTS), optical biosensors, in situ microscope, surface plasmon resonance (SPR), and reflectometric interference spectroscopy (RIF). 相似文献
4.
Rudolf Gompper Jan-Gerd Hansel Joachim Hock Kurt Polborn Elmar Dormann Hubert Winter 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):521-525
Abstract Novel dithiolene metal complexes, some of which absorb in the near infrared, and tetrathiafulvalenes, in particular tetraiodotetrathia- fulvalene, have been prepared, and their magnetic properties studied. 相似文献
5.
Communicated by Karl H. Hofmann 相似文献
6.
p-Nitrophenol (pNP) and its conjugated metabolites, generated in a perfused rat liver preparation, are readily separated and quantitated in serum perfusate and bile samples using a reverse-phase high-performance liquid chromatographic method. Serum perfusate samples can be analyzed following protein precipitation with acetonitrile: following protein precipitation with 1.5 M perchloric acid (1 part to 2 parts serum) there was degradation of pNP sulfate to pNP when samples were stored at room temperature. pNP can also be analyzed in blood perfusate samples following extraction with a number of organic solvents including ethyl acetate or isobutanol-methylene chloride (4:1, v/v). Rat liver perfusions at a constant input concentration of 40 microM demonstrated a high hepatic extraction ratio of pNP (mean of 0.90) due to the formation of the sulfate and glucuronide conjugates; no pNP glucoside was detected in perfusate or bile samples. 相似文献
7.
It was recently suggested that transient dynamical properties were of some use to predict equilibrium critical properties of 2D and 3D models of statistical mechanics on the lattice. We investigate such dynamical properties for three related models with competitive interactions, namely the ANNNI model, the brickwork model, and the BNNNI model. In spite of known differences in their equilibrium phase diagrams, our simulations display similar transient dynamical behaviors for all three models. The reliability of this method for probing equilibrium properties seems therefore questionable even for rather simple magnetic models without any structural disorder.On leave from Centre de Physique Théorique, Ecole Polytechnique, 91128, Palaiseau Cedex, France. 相似文献
8.
Tobias Hansel 《Journal of Mathematical Fluid Mechanics》2011,13(3):405-419
We consider the equations of Navier–Stokes modeling viscous fluid flow past a moving or rotating obstacle in
\mathbb Rd{\mathbb R^d} subject to a prescribed velocity condition at infinity. In contrast to previously known results, where the prescribed velocity
vector is assumed to be parallel to the axis of rotation, in this paper we are interested in a general outflow velocity. In
order to use L
p
-techniques we introduce a new coordinate system, in which we obtain a non-autonomous partial differential equation with an
unbounded drift term. We prove that the linearized problem in
\mathbb Rd{\mathbb R^d} is solved by an evolution system on
Lps(\mathbb Rd){L^p_{\sigma}(\mathbb R^d)} for 1 < p < ∞. For this we use results about time-dependent Ornstein–Uhlenbeck operators. Finally, we prove, for p ≥ d and initial data
u0 ? Lps(\mathbb Rd){u_0\in L^p_{\sigma}(\mathbb R^d)}, the existence of a unique mild solution to the full Navier–Stokes system. 相似文献
9.
Communicated by Karl H. Hofmann 相似文献
10.
Sans résumé 相似文献