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1.
M. Amar D. Andreucci R. Gianni C. Timofte 《Journal of Mathematical Analysis and Applications》2021,493(2):124533
We prove a well-posedness result for two pseudo-parabolic problems, which can be seen as two models for the same electrical conduction phenomenon in heterogeneous media, neglecting the magnetic field. One of the problems is the concentration limit of the other one, when the thickness of the dielectric inclusions goes to zero. The concentrated problem involves a transmission condition through interfaces, which is mediated by a suitable Laplace-Beltrami type equation. 相似文献
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A routine method for the determination of chloride, nitrate and sulfate anions in rainwater by capillary electrophoresis was developed. The system uses an end-column non-suppressed conductivity detector. Linear calibration plots were generated from 0.050 to 20 mg/l, which is the range generally found in wet depositions. Accuracy and precision were evaluated by analyzing certified standards of simulated rainwater and environmental samples, or by comparing CE results with those obtained by IC, the reference technique for anion analysis in wet deposition. The reproducibility of the method was satisfactory except at the lower and upper limits of the analytical range. Sensitivity lay in the range of few μg/l. 相似文献
4.
Carlo Anchisi Luciana Corda Antonio Maccioni Gianni Podda 《Journal of heterocyclic chemistry》1982,19(1):141-144
The action of acyl halides on heterocyclic compounds of five-membered rings containing an O-M-O (M ? P, As, Sb) linkage is described. The reactions were either carried out in the presence of a solvent (benzene or toluene) or by direct heating of the reagent with the substrate. In the case of arsole, stibole and stannole derivatives, the cleavage of O-M bond and the formation of the respective mono- and diesters were always obtained, while with the phospholes, no cleavage of the compounds was observed. The products IIa-c (M = Sb) have been obtained in excellent yields starting from VIa-c and antimony trichloride. The structure of the compounds which were prepared was determined by analytical and spectroscopic methods and also by comparations with authentic samples where possible. 相似文献
5.
The use of the simplex procedure as a non-linear least-squares curve-fitting method is proposed for evaluation of equivalence points in sigmoidal and segmented titration curves. The application of this procedure to theoretical curves affected by different amounts of random noise indicates its effectiveness and accuracy for locating the correct end-point in titrations characterized by very low reaction constants. The relevant results are compared with those obtained by other regression methods as well as by the first-derivative and Gran approaches. 相似文献
6.
Carlo Bruno Eleonora Ussano Gianni Barucca Davide Vanossi Giovanni Valenti Edward A. Jackson Andrea Goldoni Lucio Litti Simona Fermani Luca Pasquali Moreno Meneghetti Claudio Fontanesi Lawrence T. Scott Francesco Paolucci Massimo Marcaccio 《Chemical science》2021,12(23):8048
The presence of non-hexagonal rings in the honeycomb carbon arrangement of graphene produces rippled graphene layers with valuable chemical and physical properties. In principle, a bottom-up approach to introducing distortion from planarity of a graphene sheet can be achieved by careful insertion of curved polyaromatic hydrocarbons during the growth of the lattice. Corannulene, the archetype of such non-planar polyaromatic hydrocarbons, can act as an ideal wrinkling motif in 2D carbon nanostructures. Herein we report an electrochemical bottom-up method to obtain egg-box shaped nanographene structures through a polycondensation of corannulene that produces a new conducting layered material. Characterization of this new polymeric material by electrochemistry, spectroscopy, electron microscopy (SEM and TEM), scanning probe microscopy, and laser desorption-ionization time of flight mass spectrometry provides strong evidence that the anodic polymerization of corannulene, combined with electrochemically induced oxidative cyclodehydrogenations (Scholl reactions), leads to polycorannulene with a wavy graphene-like structure.A bottom-up synthesis of wavy graphene structures obtained through an anodic polymerization process, combined with an electrochemically triggered oxidative cyclodehydrogenation, of the bowl-shaped polyaromatic hydrocarbon corannulene. 相似文献
7.
Gilberto Schiavon Gianni Zotti Gino Bontempelli 《Journal of Electroanalytical Chemistry》1984,161(2):323-335
The electrochemical reduction of [Ni(PPh3)2(p-C6H4Br)Br] in acetonitrile results in a polymeric coating of a nickel-containing poly-p-phenylene, formulated as [-Ni(p-C6H4)n-] (n=6?7) on the basis of elemental analysis, IR, UV, MS and ESCA measurements. This coating is found to undergo a two-electron reversible reduction and a one-electron reversible oxidation with a large potential window (3.6 V), without the polymeric film being destroyed. Moreover, the polymer obtained is shown to be electroactive towards dissolved reactants via permeation or mediated electron transfer, depending on the molecular size of the electroactive species employed. 相似文献
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9.
Bendazzoli Gianni L. Raimondi Mario Garetz Bruce A. George Thomas F. Morokuma Keiji 《Theoretical chemistry accounts》1977,44(4):341-350
Semiclassical calculations are carried out by two methods for the problem of collision-induced predissociation of electronically excited I2. The first method is that of surface-hopping with the Landau-Zener model. The second method is similar to surface-hopping, except that analytic continuation of the adiabatic potential energy surfaces replaces the Landau-Zener model. Results of the calculations by the two methods compare favorably with each other and with experiment. The possible advantages of the second method are discussed.Camille and Henry Dreyfus Teacher-Scholar, Alfred P. Sloan Research Fellow. 相似文献
10.
P. A. Temussi F. Lelj T. Tancredi M. A. Castiglione Morelli A. Pastore 《International journal of quantum chemistry》1984,26(5):889-906
The structure-activity relationship of sweet molecules is chosen as an example to illustrate a mechanistic approach of soft agonist-receptor interactions. It is shown that an essentially geometric model of the receptor site can explain the activity of most sweet molecules, both rigid and flexible. The relevant conformations of flexible molecules in solution are extracted from a combination of NMR data and of energy calculations. A possible experimental simulation of the receptor environment in solution is illustrated by the complex of a dipeptide sweetener with a crown-ether. 相似文献