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Base-promoted 5-exo-dig cyclizations of aza-propargylglycinamides provided N-amino-imidazolin-2-one peptide mimics, which exhibited turn geometry in X-ray crystallographic and NMR spectroscopic analyses. Sonogashira coupling prior to cyclization afforded N-amino-imidazolin-2-ones with diverse 4-position aromatic substituents with potential to serve as Phe and Trp mimics. 相似文献
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Measurement of strong photon recycling in ultra‐thin GaAs n/p junctions monolithically integrated in high‐photovoltage vertical epitaxial heterostructure architectures with conversion efficiencies exceeding 60% 下载免费PDF全文
F. Proulx M. C. A. York P. O. Provost R. Arès V. Aimez D. P. Masson S. Fafard 《固体物理学:研究快报》2017,11(2)
Photon‐recycling effects are studied experimentally in photovoltaic power converting III–V semiconductor devices designed with the vertical epitaxial heterostructure architecture (VEHSA). The responsivity of VEHSA structures with multiple thin GaAs n/p junctions is measured for various optical input powers and for different wavelength detuning values with respect to the peak of the spectral response. While the detuning of the optical excitation decreases the external quantum efficiency and the responsivity at low input powers, this study demonstrates that at high optical intensities, a large fraction of the performance can be recovered despite significant detuning values. The photon coupling effects therefore broaden the spectral range for which the VEHSA devices convert high‐power optical inputs with high efficiencies into an electrical output having a preset voltage. The devices exhibit a near optimum responsivity of up to 0.645 A/W for tuned excitation conditions or at high optical intensities for spectral detuning values of up to ~25 nm and corresponding to an external quantum efficiency of ~94%. Efficiencies of 62.0% and 61.8% have been obtained for current‐matched excitations and for a detuning of >10 nm, respectively. An output power of 5.87 W is reported and an open circuit voltage enhancement of 92 meV per n/p junction is measured compared to a device with a side by side planar architecture. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
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The 13C chemical shifts of nine ortho-substituted phenols have been determined in cyclohexane and in dimethyl sulfoxide. All data were acquired in duplicate upon c.w. and FT instrumentation and both sets of data are presented. The chemical shifts at carbons 1, 2 and 3 are correlated with the parameter Q. Q has been defined as P/Ir3 where P is the polarizability of the adjacent C? X bond, I is the first ionization potential of the elements F, Cl, Br, I and H, and r is the C? X bond length. Experimental values of Q are available for other substituents. The field and resonance parameters of Swain and Lupton may be combined with Q to form a three part multiple regression correlation which is more exact than that with Q alone and which applies to all carbons in the aromatic ring. The results of this study suggest that only one value of the Q parameter is needed to characterize the behavior of the nitro group in these solvent systems. This conclusion is contrasted with earlier results of the effect of substituents on proton chemical shifts in these systems. 相似文献
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A. Essoltani P. Proulx M. I. Boulos A. Gleizes 《Plasma Chemistry and Plasma Processing》1994,14(3):301-315
The net volumetric emission coefficient was calculated using the escape factor method for Ar/Fe and Ar/H2/Fe plasmas, at atmospheric pressure, over the temperature range from 3000 K to 30,000 K. The calculation involved 712 lines for Ar I, Ar II, and Ar III, 3481 lines for Fe I, Fe II, and Fe III, and 230 lines for H in the Ar/H2/Fe case. A semiempirical method was used for the determination of line profiles and line broadening. The results show a strong influence of the presence of even traces of iron vapors at low temperatures where the volumetric emission increases by several orders of magnitude. Special attention is given to self-absorption of the argon resonance lines which prevents the radiation from escaping within a few millimeters from the emission source. 相似文献
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Langeroudi EG Petre CF Azizi A Proulx E Larachi F 《Journal of separation science》2011,34(13):1568-1573
A capillary electrophoretic (CE) protocol was developed for the separation and quantification of free cyanide and zinc cyanide complex, two key species in gold cyanidation of zinc-bearing sulfidic ores. Several common carrier electrolytes were implemented in an indirect UV detection method. The effect of electric field strength, injection volume, concentration of electro-osmotic flow (EOF) modifier and UV-absorbing agent in background electrolyte (BGE) was examined while peak height, peak area and noise were considered for optimization. The best results were obtained using a BGE that contained 35 mM sodium chromate, 12 mM free cyanide and 0.45 mM hexamethonium bromide at pH 10.5. Free cyanide concentration was compared to that measured with the conventional silver nitrate titration method in solutions containing free cyanides and weak cyano-complexes. The developed CE protocol proved very robust in capturing the concentration of free cyanides (4% error) unlike the titration method which exhibited substantial sensitivity to the interfering weak cyano-complexes (38% error). 相似文献
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The 5D0→7F0-2 emission of Eu3+ in cordierite is reported. Fluorescence line-narrowed emission by the 5D0←7F0 transition was used to study local structure around the Eu3+ ion in cordierite glass. It was found that the Eu3+ ion forms quasi-molecular complexes with the non-bridging oxygen, enabling the FLN data to be accounted for in terms of a single non-random distribution of crystal field strengths. 相似文献
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Serge Caron Claude ParéPatrick Paradis Huimin ZhengAntoine Proulx André Fougères 《Journal of chromatography. A》2010,1217(20):3435-3440
A fiber optic sensor has been used for real-time measurement of the migration rates of all the compounds in a mixture separated by gas chromatography. The sensor makes use of a coated capillary optical fiber as the column. This new type of waveguide consists in a polarization-maintaining optical core positioned close to the capillary edge along the entire fiber length. The optical detection is performed through the coupling of the two polarization modes of the waveguide and this coupling is detected by a polarimetric interferometry technique. Through some signal processing, the resulting interferogram provides the migration rates of the various compounds of a gas mixture flowing in the capillary. One of the major benefits of this optical migration rate sensing is that the detection of each velocity peak appears as soon as the analyte enters the capillary fiber and the peaks are constantly measured during the whole separation process. Carrier gas acceleration occurring in the column is plainly demonstrated. This paper presents a proof-of-concept on a qualitative basis. The experiments were done at 29 °C because the current opto-fluidic set-up cannot withstand a higher temperature. 相似文献
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Renaud P Goyette M Chartier S Zhornitski S Trottier D Rouleau JL Proulx J Fedoroff P Bradford JP Dassylva B Bouchard S 《Nonlinear dynamics, psychology, and life sciences》2010,14(4):463-489
Sexual arousal and gaze behavior dynamics are used to characterize deviant sexual interests in male subjects. Pedophile patients and non-deviant subjects are immersed with virtual characters depicting relevant sexual features. Gaze behavior dynamics as indexed from correlation dimensions (D2) appears to be fractal in nature and significantly different from colored noise (surrogate data tests and recurrence plot analyses were performed). This perceptual-motor fractal dynamics parallels sexual arousal and differs from pedophiles to non-deviant subjects when critical sexual information is processed. Results are interpreted in terms of sexual affordance, perceptual invariance extraction and intentional nonlinear dynamics. 相似文献
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