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排序方式: 共有211条查询结果,搜索用时 312 毫秒
21.
22.
We report on a mid-infrared (mid-IR) source consisting of an approximately 10 W average-power, linearly polarized 1.54 microm wavelength pulsed fiber source pumping an optical parametric oscillator. From this source, we obtained average power in excess of 1 W in the 3.8-4.0 microm wavelength range at a pulse repetition frequency of 100 kHz. With a slightly different setup, we also achieved an average power of 0.25 W at 4.5 microm wavelength. To our knowledge, these values represent the highest mid-IR power obtained through wavelength conversion of an eye-safe fiber source. 相似文献
23.
Canioni R Marchal-Roch C Leclerc-Laronze N Haouas M Taulèlle F Marrot J Paul S Lamonier C Paul JF Loridant S Millet JM Cadot E 《Chemical communications (Cambridge, England)》2011,47(22):6413-6415
{Mo(132)} Keplerate anion reacts with tellurites to give a soluble precursor to produce in hydrothermal conditions single-phase M1 MoVTeO light-alkanes oxidation catalyst. Characterization of this Te-containing intermediate by single-crystal X-ray diffraction, (125)Te NMR, UV-visible and redox titration reveals a molybdotellurite anion as a crown-capped Keggin derivative. 相似文献
24.
The accuracy of tomographic particle image velocimetry for measurements of a turbulent boundary layer 总被引:1,自引:0,他引:1
Callum Atkinson Sebastien Coudert Jean-Marc Foucaut Michel Stanislas Julio Soria 《Experiments in fluids》2011,50(4):1031-1056
To investigate the accuracy of tomographic particle image velocimetry (Tomo-PIV) for turbulent boundary layer measurements,
a series of synthetic image-based simulations and practical experiments are performed on a high Reynolds number turbulent
boundary layer at Reθ = 7,800. Two different approaches to Tomo-PIV are examined using a full-volume slab measurement and a thin-volume “fat” light
sheet approach. Tomographic reconstruction is performed using both the standard MART technique and the more efficient MLOS-SMART
approach, showing a 10-time increase in processing speed. Random and bias errors are quantified under the influence of the
near-wall velocity gradient, reconstruction method, ghost particles, seeding density and volume thickness, using synthetic
images. Experimental Tomo-PIV results are compared with hot-wire measurements and errors are examined in terms of the measured
mean and fluctuating profiles, probability density functions of the fluctuations, distributions of fluctuating divergence
through the volume and velocity power spectra. Velocity gradients have a large effect on errors near the wall and also increase
the errors associated with ghost particles, which convect at mean velocities through the volume thickness. Tomo-PIV provides
accurate experimental measurements at low wave numbers; however, reconstruction introduces high noise levels that reduces
the effective spatial resolution. A thinner volume is shown to provide a higher measurement accuracy at the expense of the
measurement domain, albeit still at a lower effective spatial resolution than planar and Stereo-PIV. 相似文献
25.
Natalia Zaitseva Leslie Carman Andrew Glenn Jason Newby Michelle Faust Sebastien Hamel Nerine Cherepy Stephen Payne 《Journal of Crystal Growth》2011,314(1):163-170
Single crystals of a pure hydrocarbon, 1,3,5-triphenylbenzene, with properties suitable for high-energy neutron detection were grown from toluene solutions using slow evaporation and temperature reduction methods with growth rates up to 10 mm/day. Application of the rapid growth technique developed earlier for growth of large water-soluble crystals shows that crystals of aromatic compounds can be successfully grown from solutions in large volumes required for their use as scintillator materials for radiation detection. 相似文献
26.
Phuoc KT Corde S Shah R Albert F Fitour R Rousseau JP Burgy F Mercier B Rousse A 《Physical review letters》2006,97(22):225002
We demonstrate that betatron x-ray radiation accurately provides direct imaging of electrons trajectories accelerated in laser wakefields. Experimental far field x-ray beam profiles reveal that electrons can follow similar transverse trajectories with typical excursions of 1.5 microm+/-0.5 microm in the plane of laser polarization and 0.7 microm+/-0.2 microm in the plane perpendicular. 相似文献
27.
We consider two quasi-linear initial-value Cauchy problems on ? d : a parabolic system and an hyperbolic one. They both have a first order non-linearity of the form φ(t, x, u)·?u, a forcing term h(t, x, u) and an initial condition u 0 ∈ L ∞(? d ) ∩ C ∞(? d ), where φ (resp. h) is smooth and locally (resp. globally) Lipschitz in u uniformly in (t, x). We prove the existence of a unique global strong solution for the parabolic system. We show the existence of a unique local strong solution for the hyperbolic one and we give a lower bound regarding its blow up time. In both cases, we do not use weak solution theory but a direct construction based on parabolic schemes studied via a stochastic approach and a regularity result for sequences of parabolic operators. The result on the hyperbolic problem is performed by means of a non-classical vanishing viscosity method. 相似文献
28.
Antonia Youssef Anne von Koschembahr Sylvain Caillat Sebastien Corre Marie‐Dominique Galibert Thierry Douki 《Photochemistry and photobiology》2019,95(1):237-243
Exposure to solar UV is at the origin of numerous photodegradation pathways in biomolecules. Tryptophan is readily modified by UVB radiation into ring‐opened and oxidized photoproducts. One of them, 6‐formylindolo[3,2‐b]carbazole (FICZ), has been extensively studied in the recent years because it very efficiently binds to AhR, a major factor in numerous biologic processes, such as metabolism of xenobiotics. Unfortunately, little information is available on the actual yield of FICZ upon exposure to low and biologically relevant doses of UV radiation. In the present work, we used a sensitive and specific HPLC‐tandem mass spectrometry assay to quantify a series of photoproducts induced by UVB and simulated sunlight (SSL) in solutions of tryptophan. FICZ represented only a minute amount of the photoproducts (0.02 and 0.03%, respectively). Experiments were repeated in culture medium where the yield of FICZ was also found to be very low, even when Trp was added. Last, no FICZ could be detected in cytosolic fractions of cultured cells exposed to SSL. Altogether, the present results show that FICZ is a very minor photoproduct and that it cannot be considered the only endogenous photoproduct responsible for the induction of AhR‐dependent responses in UV‐irradiated cells. 相似文献
29.
We present a physical- and link-level design for the creation of entangled pairs to be used in quantum repeater applications where one can control the noise level of the initially distributed pairs. The system can tune dynamically, trading initial fidelity for success probability, from high fidelity pairs (F=0.98 or above) to moderate fidelity pairs. The same physical resources that create the long-distance entanglement are used to implement the local gates required for entanglement purification and swapping, creating a homogeneous repeater architecture. Optimizing the noise properties of the initially distributed pairs significantly improves the rate of generating long-distance Bell pairs. Finally, we discuss the performance trade-off between spatial and temporal resources. 相似文献
30.
The convergent synthesis of N-Boc-(2R,3R,8R,9R,4E,6E)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldecadenoic acid (enantio-N-Boc-ADDA) is reported. Our flexible approach takes advantage of highly efficient non-aldol aldol and cross-metathesis methodologies. 相似文献