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991.
Pierre Strobel Hervé Muguerra Sylvie Hébert Claire Colin 《Journal of solid state chemistry》2009,182(7):1872-5186
Solid-state synthesis of Na0.71Co1−xRuxO2 compositions shows that ruthenium can be substituted for cobalt in the hexagonal Na0.71CoO2 phase up to x=0.5. The cell expands continuously with increasing ruthenium content. All mixed Co-Ru phases show a Curie-Weiss behaviour with no evidence of magnetic ordering down to 2 K. Unlike the parent phase Na0.71CoO2, ruthenium-substituted phases are all semiconducting. They exhibit high thermoelectric power, with a maximum of 165 μV/K at 300 K for x=0.3. The Curie constant C and Seebeck coefficient S show a non-monotonic evolution as a function of ruthenium content, demonstrating a remarkable interplay between magnetic properties and thermoelectricity. The presence of ruthenium has a detrimental effect on water intercalation and superconductivity in this system. Applying to Ru-substituted phases the oxidative intercalation of water known to lead to superconductivity in the NaxCoO2 system yields a 2-water layer hydrate only for x=0.1, and this phase is not superconducting down to 2 K. 相似文献
992.
Hannah Johnson Claire E. Eyers Patrick A. Eyers Robert J. Beynon Simon J. Gaskell 《Journal of the American Society for Mass Spectrometry》2009,20(12):2211-2220
Quantification of the stoichiometry of phosphorylation is usually achieved using a mixture of phosphatase treatment and differential
isotopic labeling. Here, we introduce a new approach to the concomitant determination of absolute protein concentration and
the stoichiometry of phosphorylation at predefined sites. The method exploits QconCAT to quantify levels of phosphorylated
and nonphosphorylated peptide sequences in a phosphoprotein. The nonphosphorylated sequence is used to determine the absolute
protein quantity and serves as a reference to calculate the extent of phosphorylation at the second peptide. Thus, the stoichiometry
of phosphorylation and the absolute protein concentration can be determined accurately in a single experiment. 相似文献
993.
994.
Lionel Excoffon Claire Andre Nadine Magy Samuel Limat Yves C. Guillaume 《Chromatographia》2009,70(11-12):1569-1573
In Alzheimer’s disease, it has been proposed that glycosaminoglycans facilitate amyloid fibril formation and/or stabilize the plaque aggregates. Chondroitin sulfates are sulfated glycosaminoglycans represented an ideal distribution of charge for amyloid-β (Aβ) interactions. Recent studies have suggested a possible link between the neurotoxicity of aluminum and the pathogenesis of Alzheimer’s disease. In this paper, the interaction of Aβ with chondroitin sulfates immobilized on a chromatographic column and the role of aluminum had been studied using a biochromatographic approach (molecular chromatography). A novel biochromatographic column was developed in our laboratory for studying this interaction. This study demonstrated that the aluminum interacted with Aβ and played a role in the Aβ/chondroitin sulfates association. For a Al3+ concentration (x) in the medium less than 30 μmM, the Aβ/chondroitin sulfates binding decreased with x due to a decrease of the charge–charge interactions between Aβ and its chondroitin sulfates binding site. Above 30 μmM of Al3+ in the medium, the affinity of Aβ to chondroitin sulfates increased slightly with x because the net number of ions (n) (Al3+ or Cl?) released or bound upon complex formation is low. As well, it was clearly demonstrated, that above 30 μmM the n value depend on the Al3+ concentration in the bulk solvent. This dependence was due to a gradual and conformational change of the Aβ which around 80 μmM adopted a less flexible structure; its binding site was thus less accessible to Aβ and Aβ/chondroitin sulfates association decreased slightly. 相似文献
995.
Tancredi Carli Dan Clements Amanda Cooper-Sarkar Claire Gwenlan Gavin P. Salam Frank Siegert Pavel Starovoitov Mark Sutton 《The European Physical Journal C - Particles and Fields》2010,66(3-4):503-524
A method to facilitate the consistent inclusion of cross-section measurements based on complex final-states from HERA, TEVATRON and the LHC in proton parton density function (PDF) fits has been developed. This can be used to increase the sensitivity of LHC data to deviations from Standard Model predictions. The method stores perturbative coefficients of NLO QCD calculations of final-state observables measured in hadron colliders in look-up tables. This allows the a posteriori inclusion of parton density functions (PDFs), and of the strong coupling, as well as the a posteriori variation of the renormalisation and factorisation scales in cross-section calculations. The main novelties in comparison to original work on the subject are the use of higher-order interpolation of Lagrangian form, which substantially improves the trade-off between accuracy and memory use, and a CPU and computer memory optimised way to construct and store the look-up table using modern software tools. It is demonstrated that a sufficient accuracy on the cross-section calculation can be achieved with reasonably small look-up table size by using the examples of jet production and electro-weak boson (Z, W) production in proton-proton collisions at a center-of-mass energy of 14 TeV at the LHC. The use of this technique in PDF fitting is demonstrated in a PDF-fit to HERA data and simulated LHC jet cross-sections as well as in a study of the jet cross-section uncertainties at various centre-of-mass energies. 相似文献
996.
试提出一种高荧光及强背景噪声情况下表面增强拉曼散射光谱的提取方法。该方法从分析荧光谱及背景噪声信号的组成入手,构建相应模型对荧光谱及噪声信号进行估计,通过比较估计结果与实际数据的差别识别谱峰信号,并定位谱峰的基底位置。通过在若丹明6G、前列腺特异抗原测量及pH值传感实验中的实际应用检验可知,该方法可提高表面增强拉曼散射光谱信号的分辩率和测量准确度,在微量物质鉴别及物质含量定量测量方面有较好的应用前景。 相似文献
997.
We demonstrate on-chip hybrid integration of chalcogenide glass waveguides and quantum cascade lasers (QCLs). Integration is achieved using an additive solution-casting and molding method to directly form As(2)S(3) strip waveguides on an existing QCL chip. Integrated As(2)S(3) strip waveguides constructed in this manner display strong optical confinement and guiding around 90° bends, with a NA of 0.24 and bend loss of 12.9dB at a 1mm radius (λ=4.8μm). 相似文献
998.
Philippe FD Prada C de Rosny J Clorennec D Minonzio JG Fink M 《The Journal of the Acoustical Society of America》2008,124(2):779-787
This paper reports the results of an investigation into extracting of the backscattered frequency signature of a target in a waveguide. Retrieving the target signature is difficult because it is blurred by waveguide reflections and modal interference. It is shown that the decomposition of the time-reversal operator method provides a solution to this problem. Using a modal theory, this paper shows that the first singular value associated with a target is proportional to the backscattering form function. It is linked to the waveguide geometry through a factor that weakly depends on frequency as long as the target is far from the boundaries. Using the same approach, the second singular value is shown to be proportional to the second derivative of the angular form function which is a relevant parameter for target identification. Within this framework the coupling between two targets is considered. Small scale experimental studies are performed in the 3.5 MHz frequency range for 3 mm spheres in a 28 mm deep and 570 mm long waveguide and confirm the theoretical results. 相似文献
999.
1000.
Claire Bouvy Evgeny Chelnokov Wladimir Marine Robert Sporken Bao-Lian Su 《Journal of Non》2009,355(18-21):1152-1156
ZnO@mesoporous silica nanocomposite was prepared by the impregnation of a CMI-1 material in a Zn(NO3)2 solution followed by calcination under O2. Intensive characterization was carried out by N2 adsorption–desorption measurements, scanning and transmission electron microscopy. The optical properties of the ZnO@mesoporous silica nanocomposite were studied by photoluminescence spectroscopy. Quantum Size Effect was firstly demonstrated by subjecting the sample to a 254 nm excitation light, and was further confirmed by using a 680 nm excitation laser beam, which implies a two-photon absorption process. By focusing the 680 nm laser beam on different places in the sample, a very localized random laser effect, also induced by a two-photon absorption process, was detected. 相似文献