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181.
182.
We investigate multiple-soliton pattern formations in a figure-of-eight passively mode-locked fiber laser. Operation in the anomalous dispersion regime with a double-clad fiber amplifier allows generation of up to several hundreds of solitons per round trip. We report the observation of remarkable soliton distributions: soliton gas, soliton liquid, soliton polycrystal, and soliton crystal, thus indicating the universality of such complexes. 相似文献
183.
Spectral compression by self-phase modulation of amplitude- and phase-shaped pulses is demonstrated as superior compared to pulses that have only been phase shaped. We synthesize linearly negatively chirped parabolic pulses, which we send through a nonlinear photonic crystal fiber, in which self-phase modulation compresses the spectrum of the pulses to within 20% of the Fourier transform limit. 相似文献
184.
A simple oxydative procedure converted Z-L-threonine methyl ester into the corresponding (2S)-β-keto ester: Starting material for the synthesis of labelled threonine derivatives. 相似文献
185.
We give in the present Note a proof of the Bellissard gap-labelling conjecture for quasi-crystals. Our main tools are the measured index theorem for laminations on the one hand, and the naturality of the longitudinal Chern character on the other hand. To cite this article: M.-T. Benameur, H. Oyono-Oyono, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 667–670. 相似文献
186.
Delpoux O Gourier D Binet L Vezin H Derenne S Robert F 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(5):1301-1310
Insoluble organic matter (IOM) of Orgueil and Tagish Lake meteorites are studied by CW-EPR and pulsed-EPR spectroscopies. The EPR line is due to polycyclic paramagnetic moieties concentrated in defect-rich regions of the IOM, with concentrations of the order of 4x10(19) spin/g. CW-EPR reveals two types of paramagnetic defects: centres with S=1/2, and centres with S=0 ground state and thermally accessible triple state S=1. In spite of the Lorentzian shape of the EPR and its narrowing upon increasing the spin concentration, the EPR line is not in the exchange narrowing regime as previously deduced from multi-frequency CW-EPR [L. Binet, D. Gourier, Appl. Magn. Reson. 30 (2006) 207-231]. It is inhomogeneously broadened as demonstrated by the presence of nuclear modulations in the spin-echo decay. The line narrowing, similar to an exchange narrowing effect, is the result of an increasing contribution of the narrow line of the triplet state centres in addition to the broader line of doublet states. Hyperfine sublevel correlation spectroscopy (HYSCORE) of hydrogen and (13)C nuclei indicates that IOM* centres are small polycyclic moieties that are moderately branched with aliphatic chains, as shown by the presence of aromatic hydrogen atoms. On the contrary the lack of such aromatic hydrogen in triplet states suggests that these radicals are most probably highly branched. Paramagnetic centres are considerably enriched in deuterium, with D/H approximately 1.5+/-0.5x10(-2) of the order of values existing in interstellar medium. 相似文献
187.
Let S be the multiplicative semigroup of q×q matrices with positive entries such that every row and every column contains a strictly positive element. Denote by (X
n
)
n≥1 a sequence of independent identically distributed random variables in S and by X
(n)=X
n
⋅⋅⋅
X
1, n≥1, the associated left random walk on S. We assume that (X
n
)
n≥1 satisfies the contraction property
where S° is the subset of all matrices which have strictly positive entries. We state conditions on the distribution of the random
matrix X
1 which ensure that the logarithms of the entries, of the norm, and of the spectral radius of the products X
(n), n≥1, are in the domain of attraction of a stable law.
相似文献
188.
Clavé G Boutal H Hoang A Perraut F Volland H Renard PY Romieu A 《Organic & biomolecular chemistry》2008,6(17):3065-3078
A convenient, versatile and straightforward synthesis of a novel heterotrifunctional peptide-based linker molecule is described. This generic bio-labelling reagent contains an amine-reactive N-hydroxysuccinimidyl carbamate moiety, an aldehyde/ketone-reactive aminooxy group and a thiol group with a propensity to form urea, oxime and thioether linkages respectively. The full chemical orthogonality between the free aminooxy and thiol functionalities was demonstrated through the preparation of a fluorescent reagent suitable for the selective staining of a carboxaldehyde-modified surface by means of oxime ligation. The absence of reactivity of these two functions toward the nucleophile-sensitive active carbamate was obtained by using temporary aminooxy- and thiol-protecting groups removable under mild conditions. The utility of the linker molecule to cross-link three different molecular partners has been illustrated by the preparation of fluorescent tripod-functionalised surfaces which may be useful in developing new peptide microarrays and related immunosensors. 相似文献
189.
Proton Transport in a Highly Conductive Porous Zirconium‐Based Metal–Organic Framework: Molecular Insight
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Dr. Daiane Damasceno Borges Dr. Sabine Devautour‐Vinot Dr. Hervé Jobic Dr. Jacques Ollivier Dr. Farid Nouar Dr. Rocio Semino Dr. Thomas Devic Dr. Christian Serre Prof. Francesco Paesani Prof. Guillaume Maurin 《Angewandte Chemie (International ed. in English)》2016,55(12):3919-3924
The water stable UiO‐66(Zr)‐(CO2H)2 MOF exhibits a superprotonic conductivity of 2.3×10?3 S cm?1 at 90 °C and 95 % relative humidity. Quasi‐elastic neutron scattering measurements combined with aMS‐EVB3 molecular dynamics simulations were able to probe individually the dynamics of both confined protons and water molecules and to further reveal that the proton transport is assisted by the formation of a hydrogen‐bonded water network that spans from the tetrahedral to the octahedral cages of this MOF. This is the first joint experimental/modeling study that unambiguously elucidates the proton‐conduction mechanism at the molecular level in a highly conductive MOF. 相似文献
190.
This review covers the state of the art of the analysis of real (or non-ideal) samples on microfluidic devices. A real sample analysis performed on microfluidics conceptually involves the complete integration of sample preparation, analyte separation, and detection on these platforms. Different “lab-on-a-chip” approaches have emerged in relevant application areas such as clinical, environmental, and food analysis which will be critically illustrated and discussed with respect to the strengths and weakness found. Likewise, the main challenges and perspectives will also be commented on. 相似文献