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131.
We have determined the photophysical properties of [Eu(C12H8N2)2](NO3)3, (EuPhen), a complex which is very promising for photonic and optoelectronic applications, because of its easy synthetic procedure and high thermal stability (up to 300 °C) combined with large sensitization efficiency and good emission quantum yield. Available experimental absorption and emission data have been analyzed by using Judd-Ofelt analysis. Moreover, semi-empirical calculations have been used to determine the structure of the complex and to interpret the convoluted shape of the absorption spectrum. 相似文献
132.
133.
134.
Summary The transition to the zero-resistance state at 110 K has been observed in multiphasic samples of Y1.2Ba0.8CuO4−y
nominal composition. The intrinsic nature of this high-temperature superconducting state is confirmed by the jump atT
c in the specific-heat curve. 相似文献
135.
Distribution of low-density lipoprotein-bound low-molecular-weight thiols: a new analytical approach
Zinellu A Sotgia S Zinellu E Formato M Manca S Magliona S Ginanneschi R Deiana L Carru C 《Electrophoresis》2006,27(13):2575-2581
We have recently demonstrated that low-density lipoprotein (LDL) apoprotein is able to bind the most concentrated plasma thiols such as cysteine, cysteinylglycine, and homocysteine by disulfide linkage. However, the LIF CE assay employed to measure linked thiols was not sensitive enough to verify whether low concentrated plasma thiols as glutathione and glutamylcysteine are also linked to apoprotein. By modifying sample treatment and electrophoretic parameters we set up a new method with an LOQ of about 1.5 nmol/L, by which we demonstrate that LDL apoprotein binds all physiological plasma thiols. The increased sensitivity was obtained by drying released apoB thiols after reduction treatment, dissolving them directly in a low volume of derivatization buffer and decreasing the dilution factor of derivatized sample before CE injection. Moreover, by increasing the concentration of the electrolyte buffer, we improved the selectivity of peaks, in particular between glutathione (GSH) and the impurity peak derived from unreacted 5-iodoacetamidofluorescein, which in the previous electrophoretic conditions were overlapped. The method optimization, reached by searching the best combination between sample matrix and CE run buffer, is fully described. Given the potential pathologic significance of protein thiolation, the proposed method may be useful to understand the mechanisms and the balances that regulate the interaction between thiols and -SH free groups of proteins. 相似文献
136.
Coussan S Ferro Y Trivella A Rajzmann M Roubin P Wieczorek R Manca C Piecuch P Kowalski K Włoch M Kucharski SA Musiał M 《The journal of physical chemistry. A》2006,110(11):3920-3926
Cryogenic matrix isolation experiments have allowed the measurement of the UV absorption spectra of the high-energy non-chelated isomers of acetylacetone, these isomers being produced by UV irradiation of the stable chelated form. Their identification has been done by coupling selective UV-induced isomerization, infrared spectroscopy, and harmonic vibrational frequency calculations using density functional theory. The relative energies of the chelated and non-chelated forms of acetylacetone in the S0 state have been obtained using density functional theory and coupled-cluster methods. For each isomer of acetylacetone, we have calculated the UV transition energies and dipole oscillator strengths using the excited-state coupled-cluster methods, including EOMCCSD (equation-of-motion coupled-cluster method with singles and doubles) and CR-EOMCCSD(T) (the completely renormalized EOMCC approach with singles, doubles, and non-iterative triples). For dipole-allowed transition energies, there is a very good agreement between experiment and theory. In particular, the CR-EOMCCSD(T) approach explains the blue shift in the electronic spectrum due to the formation of the non-chelated species after the UV irradiation of the chelated form of acetylacetone. Both experiment and CR-EOMCCSD(T) theory identify two among the seven non-chelated forms to be characterized by red-shifted UV transitions relative to the remaining five non-chelated isomers. 相似文献
137.
Corinna Raimondo Marina Alloisio Anna Demartini Carla Cuniberti Giovanna Dellepiane Sushilkumar A. Jadhav Giovanni Petrillo Emilia Giorgetti Cristina Gellini Maurizio Muniz‐Miranda 《Journal of Raman spectroscopy : JRS》2009,40(12):1831-1837
Gold and silver nanoparticles of different size, decorated by a diacetylenic monomer having a COOH anchor group, were prepared in aqueous dispersions. Topochemical polymerization of the colloidal suspensions was obtained by UV irradiation and studied by means of spectroscopic techniques (UV–visible absorption, IR and Raman spectroscopies). A variety of polymer phases were found in the case of silver nanohybrids. The main contribution for this investigation was supplied by the Raman spectra, which provide detailed information on the polymer forms and on the preferred conformation of the alkylic side chains. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
138.
Matteo Lanzi Veronica Santacroce Davide Balestri Luciano Marchi Franca Bigi Raimondo Maggi Max Malacria Giovanni Maestri 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(20):6775-6779
A variety of linear dienynes can deliver complex tetracyclic frameworks in the presence of an IrIII complex and visible light. Product formation involves the generation of four new C?C bonds and six contiguous stereocenters, which decorate two [3.1.0] bicyclic units tethered through their bridging quaternary carbon atoms. The internal alkyne acts as a formal dicarbenoid for the generation of two cyclopropanes in these radical cation cascades. This behavior has not been previously observed for organic reactive intermediates and can be extended to intermolecular reactions and diendiynes. 相似文献
139.
T. Martens T. Munters L. Goris J. D’Haen K. Schouteden M. D’Olieslaeger L. Lutsen D. Vanderzande W. Geens J. Poortmans L. De Schepper J.V. Manca 《Applied Physics A: Materials Science & Processing》2004,79(1):27-30
The working principle of so-called organic bulk heterojunction solar cells prepared with blends of poly(2-methoxy-5-(3,7-dimethyl-octyloxy))-p-phenylene vinylene (MDMO-PPV), acting as an electron donor, and (6,6)-phenyl-C61-butyric-acid methyl ester (PCBM) (a soluble C60 derivative), acting as electron acceptor, is based on the presence of three-dimensional nanostructured pn junctions and percolation paths for charge transport. At high PCBM contents, spontaneous phase separation occurs giving rise to PCBM-rich spherical/ellipsoidal regions (electron transport) embedded in a MDMO-PPV-rich matrix (hole transport). With transmission electron microscopy and scanning probe microscopy techniques it has been demonstrated that the size of the PCBM-rich region depends strongly on the preparation conditions such as solvents and drying conditions. The morphology of the active films in high-performance bulk heterojunction solar cells is characterized by a significantly higher number and a smaller size (nanoscale) of the PCBM-rich regions than for the low-performance cells. This morphology yields both an increase of the useful photoactive volume and an increase of the percolation paths for charge transport. Towards mature and high-performance organic-based three-dimensional photovoltaics, it is clear that besides mastering the electro-optical properties of the constituting materials it also of key importance to control the nanomorphology of the solid-state blends in order to obtain efficient interpenetrating pn networks. PACS 68.37.Lp; 72.80.Le; 73.50.Pz 相似文献
140.
In this article a numerical solution for the evolution equation of a continuous time non-homogeneous semi-Markov process (NHSMP) is obtained using a quadrature method. The paper, after a short introduction to continuous time NHSMP, presents the numerical solution of the process evolution equation with a general quadrature method. Furthermore, the paper gives results that justify this approach, proving that the numerical solution tends to the evolution equation of the continuous time NHSMP. Moreover, the formulae related to some specific quadrature methods are given and a method for obtaining the discrete time NHSMP by applying a very particular quadrature formula for the discretization is shown. In this way the relation between the continuous and discrete time NHSMP is proved. Then, the problem of obtaining the continuous time NHSMP from the discrete one is considered. This problem is solved showing that the discrete process converges in law to the continuous one if the discretized time interval tends to zero. In addition, the discrete time NHSMP in matrix form is presented, and the fact that the solution to this process always exists is proved. Finally, an algorithm for solving the discrete time NHSMP is given. To illustrate the use of this algorithm for a discrete NHSMP, an example in the area of finance is presented. 相似文献