BLOCH modes dressed by evanescent waves and the generalized Goos-Hänchen effect in photonic crystals

It is common knowledge that in an infinite periodic medium, for instance, an infinite photonic crystal, the direction of propagation of a monochromatic wave packet is given by the normal to the isofrequency diagram. We show that this is no longer true in a finite size medium, due to the existence of evanescent waves near the interfaces of the photonic crystal. We derive a renormalized isofrequency diagram giving the correct direction. We give a physical interpretation, showing that this phenomenon can be considered as a generalized Goos-H?nchen effect.     

Noisy inflows cause a shedding-mode switching in flow past an oscillating cylinder

Vortex streets formed behind oscillating bluff bodies consist of arrays of groups of two, three, or four vortices classified as 2S, P+S, and 2P shedding modes, respectively. The prevailing dominant mode depends primarily on the amplitude and the frequency of the oscillation and on the Reynolds number. We investigate the effect of noise at the inflow on the stability of these vortex modes in laminar flow past a circular cylinder. We employ stochastic simulations based on a new polynomial chaos method to study the shedding-mode switching from a P+S pattern to a 2S mode in the presence of noise.     

The fractal dynamics of self-esteem and physical self

The aim of this paper was to determine whether fractal processes underlie the dynamics of self-esteem and physical self. Twice a day for 512 consecutive days, four adults completed a brief inventory measuring six subjective dimensions: global self-esteem, physical self-worth, physical condition, sport competence, attractive body, and physical strength. The obtained series were submitted to spectral analysis, which allowed their classification as fractional Brownian motions. Three fractal analysis methods (Rescaled Range analysis, Dispersional analysis, and Scaled Windowed Variance analysis) were then applied on the series. These analyses yielded convergent results and evidenced long-range correlation in the series. The self-esteem and physical self series appeared as anti-persistent fractional Brownian motions, with a mean Hurst exponent of 0.21. These results reinforce the conception of self-perception as the emergent product of a dynamical system composed of multiple interacting elements.     

Homogenization near resonances and artificial magnetism from dielectrics

The homogenization of periodic dielectric structures in harmonic regime usually leads to an effective permittivity tensor ${?}^{\mathrm{eff}}$. It has been observed by Bouchitté and Felbacq [Waves Random Media 7 (1997) 245–256], that in the high contrast case (high conductivity fibers), this tensor depends on the angular frequency ω. In this Note, we enlight a new effect induced by microscopic resonances which leads in parallel to a possibly negative effective permeability ${\mu }^{\mathrm{eff}}(\omega )$ (although the original medium is assumed to be nonmagnetic i.e. $\mu =1$). To cite this article: G. Bouchitté, D. Felbacq, C. R. Acad. Sci. Paris, Ser. I 339 (2004).     

广义基的多重散射理论

提出了任意函数基表象中的多重散射理论. 基于这个框架, 一组新基的多重散射计算表明其收敛性比传统的球谐函数基的要好, 从而可以实现更快和更节省物理内存的计算. 另外, 将多重散射矩阵分为传播矩阵和散射矩阵, 很好地描述了散射性质和减小了多重散射计算中块矩阵的尺寸.     

Optical management in high‐efficiency thin‐film silicon micromorph solar cells with a silicon oxide based intermediate reflector

In the effort to increase the stable efficiency of thin film silicon micromorph solar cells, a silicon oxide based intermediate reflector (SOIR) layer is deposited in situ between the component cells of the tandem device. The effectiveness of the SOIR layer in increasing the photo‐carrier generation in the a‐Si:H top absorber is compared for p–i–n devices deposited on different rough, highly transparent, front ZnO layers. High haze and low doping level for the front ZnO strongly enhance the current density (J_sc) in the μc‐Si:H bottom cell whereas J_sc in the top cell is influenced by the angular distribution of the transmitted light and by the reflectivity of the SOIR related to different surface roughness. A total J_sc of 26.8 mA/cm² and an initial conversion efficiency of 12.6% are achieved for 1.2 cm² cells with top and bottom cell thicknesses of 300 nm and 3 μm, and without any anti‐reflective coating on the glass. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Convenient one-pot formation of highly functionalized 5-bromo-2-aminothiazoles,potential endocannabinoid hydrolase MAGL inhibitors

Highly functionalized 5-bromo-2-amino-1,3-thiazoles bearing various substituents could be easily prepared by a rapid and efficient one-pot method, using simple starting materials and mild conditions while avoiding the use of metal catalysts or inconvenient reagents such as elemental halogens. These useful products can serve as starting materials for other reactions or as pharmacologically interesting compounds. In our work we have shown that the resulting 5-bromothiazole compounds could lead to monoacylglycerol lipase (MAGL) inhibition in the μM range.     

NMR-restrained docking of a peptidic inhibitor to the N-terminal domain of the phosphoenolpyruvate:sugar phosphotransferase enzyme I

Starting from the NMR structure of the binary complex between the N-terminal domain of the unphosphorylated enzyme I (EIN) of the phosphoenolpyruvate:sugar phosphotransferase (PTS) and the histidine-containing phosphocarrier protein (HPr), a molecular model of the phosphorylated transition state of the related complex was established using constrained simulated annealing. The coordinates of the phosphorylated EIN enzyme were then used in a second step for flexible docking of a decapeptide inhibitor of EIN whose enzyme-bound conformation itself was determined by NMR using transferred nuclear Overhauser effects. Two phosphorylation models of the peptide inhibitor were investigated and shown to be both functional. Interestingly, one model is very similar to that of the complex between EIN and its natural substrate HPr. The present study demonstrates that NMR-guided flexible docking constitutes an interesting tool for docking highly flexible peptide ligands and facilitates the upcoming protein-based design of nonpeptide EIN inhibitors for discovering new antibiotics.     

Characterisation of middle-distillates by comprehensive two-dimensional gas chromatography (GC x GC): A powerful alternative for performing various standard analysis of middle-distillates

The detailed characterisation of middle distillates is essential for a better understanding of reactions involved in refining process. Owing to higher resolution power and enhanced sensitivity, comprehensive two-dimensional gas chromatography (GC x GC) is a powerful tool for improving characterisation of petroleum samples. The aim of this paper is to compare GC x GC and various ASTM methods -- gas chromatography (GC), liquid chromatography (LC) and mass spectrometry (MS) -- for group type separation and detailed hydrocarbon analysis. Best features of GC x GC are demonstrated and compared to these techniques in terms of cost, time consumption and accuracy. In particular, a new approach of simulated distillation (SimDis-GC x GC) is proposed: compared to the standard method ASTM D2887 it gives unequal information for better understanding of conversion process.