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101.
Mariagrazia Bianchi David Chillag Mark L. Lewis Emanuele Pacifici 《Proceedings of the American Mathematical Society》2007,135(3):671-676
Let be a finite group, and write for the set of degrees of irreducible characters of . We define to be the graph whose vertex set is , and there is an edge between and if . We prove that if is a complete graph, then is a solvable group.
102.
We prove surface and volume mean value formulas for classical solutions to uniformly parabolic equations in the divergence form with low regularity of the coefficients. We then use them to prove the parabolic strong maximum principle and the parabolic Harnack inequality. We emphasize that our results only rely on the classical theory, and our arguments follow the lines used in the original theory of harmonic functions. We provide two proofs relying on two different formulations of the divergence theorem, one stated for sets with almost C1-boundary, the other stated for sets with finite perimeter. 相似文献
103.
Summary This paper concerns with the similarity analysis for a general discrete two-velocity model of the Boltzmann equation introduced by Illner [12]. We find the general groups of invariance and we get some exact solutions, recovering general results which contain either solutions extensively described in the literature or undiscovered ones.
Work supported by the C.N.R. through the G.N.F.M. 相似文献
Sommario In questa nota si applica l'analisi dei gruppi infinitesimi di trasformazione ad un modello generale discreto a due velocità dell'equazione di Boltzmann introdotto da Illner [12]. Si trovano i più generali gruppi di invarianza e si ottengono alcune soluzioni esatte, ritrovando risultati generali che contengono sia soluzioni ampiamente descritte in letteratura che nuove soluzioni.
Work supported by the C.N.R. through the G.N.F.M. 相似文献
104.
Dr. Alessandra Alberti Dr. Ioannis Deretzis Dr. Giovanna Pellegrino Dr. Corrado Bongiorno Dr. Emanuele Smecca Dr. Giovanni Mannino Dr. Filippo Giannazzo Prof. Guglielmo Guido Condorelli Dr. Nobuya Sakai Prof. Tsutomu Miyasaka Dr. Corrado Spinella Dr. Antonino La Magna 《Chemphyschem》2015,16(14):3064-3071
We investigate the degradation path of MAPbI3 (MA=methylammonium) films over flat TiO2 substrates at room temperature by means of X‐ray diffraction, spectroscopic ellipsometry, X‐ray photoelectron spectroscopy, and high‐resolution transmission electron microscopy. The degradation dynamics is found to be similar in air and under vacuum conditions, which leads to the conclusion that the occurrence of intrinsic thermodynamic mechanisms is not necessarily linked to humidity. The process has an early stage, which drives the starting tetragonal lattice in the direction of a cubic atomic arrangement. This early stage is followed by a phase change towards PbI2. We describe how this degradation product is structurally coupled with the original MAPbI3 lattice through the orientation of its constituent PbI6 octahedra. Our results suggest a slight octahedral rearrangement after volatilization of HI+CH3NH2 or MAI, with a relatively low energy cost. Our experiments also clarify why reducing the interfaces and internal defects in the perovskite lattice enhances the stability of the material. 相似文献
105.
Potential of prodendronic polyamines with modulated segmental charge density as novel coating for fast and efficient analysis of peptides and basic proteins by CE and CE‐MS
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Tanize Acunha Clara Ibáñez María Isabel Pascual Reguera Mariagiovanna Sarò Rodrigo Navarro Juan Alfonso Redondo Helmut Reinecke Alberto Gallardo Carolina Simó Alejandro Cifuentes 《Electrophoresis》2015,36(14):1564-1571
In this work, the suitability of a new polymer family has been investigated as capillary coatings for the analysis of peptides and basic proteins by CE. This polymer family has been designed to minimize or completely prevent protein–capillary wall interactions and to modify the EOF. These coating materials are linear polymeric chains bearing as side cationizable moiety a dentronic triamine derived from N,N,N’,N’‐tetraethyldiethylenetriamine (TEDETA), which is linked to the backbone through a spacer (unit labeled as TEDETAMA). Four different polymers have been prepared and evaluated: a homopolymer which comprised only of those cationizable repetitive units of TEDETAMA, and three copolymers that randomly incorporate TEDETAMA together with neutral hydrosoluble units of N‐(2‐hydroxypropyl) methacrylamide (HPMA) at different molar percentages (25:75, 50:50 and 75:25). It has been demonstrated that the composition of the copolymers influences the EOF and therefore the separation of the investigated biopolymers. Among the novel polymers studied, poly‐(TEDETAMA‐co‐HPMA) 50:50 copolymer was successfully applied as coating material of the inner capillary surface in CE‐UV and CE‐MS, providing EOF reversing together with fast and efficient baseline separation of peptides and basic proteins. Finally, the feasibility of the polymer‐coated capillary was shown through the analysis of lysozyme in a cheese sample. 相似文献
106.
Dr. Christian Schmitz Prof. Walter Leitner Dr. Giancarlo Franciò 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10696-10702
A library of α,α,α,α‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL)‐based phosphoramidites has been synthesized and applied in the Ni‐catalyzed cycloisomerization of different dienes. Through the systematic variation of the three structural motifs of the lead structure, that is, the amine moiety, the protecting group, and the aryl substituents, the ligand features could be optimized for the asymmetric cycloisomerization of the model substrate diethyl diallylmalonate. The substrate scope of the new catalytic system was extended to other diallylic substrates, including unsymmetrical dienes. Overall remarkably high activities of up to approximately 13 500 h?1, very high selectivities toward five‐membered exo‐methylenecyclopentanes, and enantioselectivities of up to 92 % ee have been achieved. 相似文献
107.
Hyperbolic models are suitable for describing invasive phenomena with a well-defined boundary. In fact, for a class of hyperbolic reaction–diffusion models derived in the context of extended thermodynamics (ET), the non-existence of smooth travelling waves has been proved under suitable assumptions on the wave speed. In this paper a hyperbolic model for the within-season dynamics of insect pathogens is derived and smooth and discontinuous travelling wave solutions are investigated. Validation of the model in point is also accomplished by searching for numerical solutions of the system of PDEs. 相似文献
108.
In this work, melt spinning experiments were tentatively used for the determination of the elongational viscosity of polymer
melts at different levels of tensile strain and strain rate. The materials examined were two high-density polyethylene grades
for blow moulding with similar number-average molecular mass but different polydispersity index. The data from melt spinning
tests were compared with transient extensional viscosity data obtained by uniform isothermal tensile tests, performed by means
of an extensional rheometer, as well as with those produced by converging flow tests (Cogswell model). The results showed
that for high strain and strain rate levels, the melt spinning experiments provide elongational viscosity data quite close
to the transient extensional viscosity values obtained from the tensile tests. 相似文献
109.
Emanuele Miserazzi Mario Alessandro SpottiRoberto Profeta Simone SpadaArnaldo Nalin Elisa MoroDaniele Andreotti 《Tetrahedron letters》2011,52(3):448-452
An interesting and surprising rearrangement was observed during the reaction of 4-N-benzyl piperazinone derivatives with Lawesson’s reagent as a thionating agent. Investigation into the possible mechanism responsible for these results is reported herein. 相似文献
110.
A fast analytical method has been developed for the determination of nine amino acids, together with serotonin, in wine samples of different origin and vintage. The method is based on capillary electrophoresis coupled to laser-induced fluorescence detection. Separation was obtained by using a fused-silica capillary (75?μm id, 74.0?cm total length, 60.0?cm length to detector) and a background electrolyte composed of carbonate buffer (20?mM, pH 9.2), applying a 20?kV voltage. Direct hydrodynamic injection of wine samples was made after an original microwave-assisted derivatisation step with 5-(4,6-dichlorotriazinyl)aminofluorescein. Fluorescence was induced by an Ar-Ion laser, exciting at 488?nm. Good linearity (r(2) >0.9990) was obtained for all considered analytes and sensitivity was also good, with limits of detection in the 7-50?ng/mL range. The method was successfully applied for the analysis of commercial Italian wines and thus seems to be suitable for the determination of the relevant amino acids and serotonin, providing good results in terms of accuracy and precision, together with the advantage of a very fast, microwave-assisted derivatisation procedure. Future applications of the method are planned to check for wine adulterations and commercial frauds. 相似文献