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31.
Martin Loeser Lorenzo Occhi Christian Vélez Raffaele Rezzonico Bernd Witzigmann 《Optical and Quantum Electronics》2006,38(12-14):1069-1075
The impact of self-heating and cavity length on the spectral emission properties of SLEDs is investigated using a state-of-the-art simulation tool. Simulated data are compared to measurements for two InP-based benchmark devices operating around 1300 nm, and excellent agreement is achieved in either case. 相似文献
32.
33.
We study the pattern formation in a lattice of locally coupled phase oscillators with quenched disorder. In the synchronized regime quasiregular concentric waves can arise which are induced by the disorder of the system. Maximal regularity is found at the edge of the synchronization regime. The emergence of the concentric waves is related to the symmetry breaking of the interaction function. An explanation of the numerically observed phenomena is given in a one-dimensional chain of coupled phase oscillators. Scaling properties, describing the target patterns are obtained. 相似文献
34.
The effect of susceptibility differences between fluid and fibers on the properties of DTI fiber phantoms was investigated. Thereto, machine-made, easily producible and inexpensive DTI fiber phantoms were constructed by winding polyamide fibers of 15 microm diameter around a circular acrylic glass spindle. The achieved fractional anisotropy was 0.78+/-0.02. It is shown by phantom measurements and Monte Carlo simulations that the transversal relaxation time T(2) strongly depends on the angle between the fibers and the B(0) field if the susceptibilities of the fibers and fluid are not identical. In the phantoms, the measured T(2) time at 3 T decreased by 60% for fibers running perpendicular to B(0). Monte Carlo simulations confirmed this result and revealed that the exact relaxation time depends strongly on the exact packing of the fibers. In the phantoms, the measured diffusion was independent of fiber orientation. Monte Carlo simulations revealed that the measured diffusion strongly depends on the exact fiber packing and that field strength and -orientation dependencies of measured diffusion may be minimal for hexagonal packing while the diffusion can be underestimated by more than 50% for cubic packing at 3 T. To overcome these effects, the susceptibilities of fibers and fluid were matched using an aqueous sodium chloride solution (83 g NaCl per kilogram of water). This enables an orientation independent and reliable use of DTI phantoms for evaluation purposes. 相似文献
35.
Background
Infections with respiratory viruses can activate the innate immune response - an important host defence mechanism in the early stage of viral infection. Interferon (IFN) release, triggered by virus infection, is an important factor in establishing an antiviral state, where IFN activation occurs prior to the onset of the adaptive immune response. 相似文献36.
Uwe Bandelow Mindaugas Radziunas Andrei Vladimirov Bernd Hüttl Ronald Kaiser 《Optical and Quantum Electronics》2006,38(4-6):495-512
We study both theoretically and experimentally typical operation regimes of 40 GHz monolithic mode-locked lasers. The underlying
Traveling Wave Equation model reveals quantitative agreement for characteristics of the fundamental mode-locking as pulse
width and repetition frequency tuning, as well as qualitative agreement with the experiments for other dynamic regimes. Especially
the appearance of stable harmonic mode-locking at 80 GHz has been predicted theoretically and confirmed by measurements. Furthermore,
we derive and apply a simplified Delay-Differential-Equation model which guides us to a qualitative analysis of bifurcations
responsible for the appearance and the breakup of different mode-locking regimes. Higher harmonics of mode-locking are predicted
by this model as well. 相似文献
37.
38.
We investigate the nature of the phase transition from the superconducting to the uniformly ordered magnetic phase in ferromagnetic superconductors by renormalization group methods. For this purpose Halperin, Lubensky, Ma's application of the-expansion to pure superconductors is extended to include the influence of magnetic order as well. Our treatment shows that in the vicinity of the ferromagnetic to superconducting phase-boundary critical fluctuations of the magnetization are absorbed into fluctuations of the magnetic field. As a consequence the transition always is first order. An additional indication to the dominance of electromagnetic effects is the irrelevance of the coupling corresponding to spin flip scattering. 相似文献
39.
Bernd S. W. Schröder 《Order》1992,9(4):311-319
The following theorem is proved: If Q=L{P
t
tT} is a finite lexicographic sum of posets such that T and all P
t
have the strong fixed point property then Q has the strong fixed point property. Moreover we show the strong fixed point property for two more classes of posets. 相似文献
40.
Bernd . Stratmann 《Indagationes Mathematicae》2003,14(1):119-134
For arbitrary parabolically semihyperbolic generalized polynomial-like maps f, we prove that on a certain interval, which contains the interval (0, HD(J(f))), the pressure function t ? P(−t log |f|) is real-analytic. Our results generalize the work of Makarov and Smirnov in [3] and [7]. 相似文献