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81.
Giuseppina Conti Ettore Santoro Luigi Resconi Giuseppe Zerbi 《Mikrochimica acta》1988,94(1-6):297-300
Highly syndiotactic poly(styrene) shows higher crystallinity and a higher melting point than the corresponding isotactic material. Temperature dependent FTIR spectra have been recorded and the structural evolution of the system from the ordered to the amorphous phase has been followed. 相似文献
82.
Specific heats at constant pressure for the mixed system K/Na/Cl/SO4 in H2O have been obtained from heat content measurements by means of a drop calorimeter between 60 and 220°C over the salt concentration range 0.5–5m, with ionic strengths up to 7.5. Measurements have also been made on aqueous K2SO4 solutions in the same temperature range between 0.3 and 1.6m. The heat capacities of the quaternary system were represented using the semiempirical Pitzer equations neglecting the mixed interaction terms as a first approximation. A comparison of experimental with calculated data shows that the ability of this method to describe the system is satisfactory even at rather high concentrations, but only for solutions of low sulphate ion content. 相似文献
83.
Paolo Bruni Carla Conti Elisabetta Giorgini Giorgio Tosi Henning Hopf Jorg Hillmer 《Monatshefte für Chemie / Chemical Monthly》1992,123(1-2):73-80
Summary Molecular complexes of mono and disubstituted [2.2]paracyclophanehydrazones with organic acceptors have been studied by means of thermodynamic and spectroscopic properties. Furthermore, the enhancement of the donor strength, induced by the hydrazono group, is viewed in the light of substituent as well as transannular effects.
Molekulare Assoziation von [2.2]Paracyclophanarylhydrazonen mit organischen Akzeptoren, 8. Mitt.
Zusammenfassung Es wurden Molekülkomplexe von mono- und disubstituierten [2.2]Paracyclophanarylhydrazonen mit organischen Akzeptoren mittels thermodynamischer und spektroskopischer Methoden untersucht. Zusätzlich wird der Anstieg in der Donorstärke, der von der Hydrazonogruppe induziert wird, im Hinblick auf Substituenten- und auch transannulare Effekte diskutiert.相似文献
84.
85.
F. Conti C. Corvaja M. Maggini F. Piu G. Scorrano A. Toffoletti 《Applied magnetic resonance》1997,13(3-4):337-346
Fulleropyrroliddine derivatives containing a TEMPO group (FPNOs) are examined in toluene solution, between 200 and 270 K, by TR-EPR spectroscopy after LASER excitation. Signals of the ground and excited states are observed and their time profiles are recorded. In presence of ferrocene the time pattern of the polarization is modified, showing the occurrence of intermolecular electron transfer from the donor ferrocene to the excited FPNOs. The rate constantk E. is obtained from the simulation of the EPR signal time evolution of the ground and excited states. 相似文献
86.
C. Bellecci A. Bonanno M. Camarca M. Conti L. La Rotonda R. Visentin 《Il Nuovo Cimento C》1984,7(3):283-291
Summary A solar plant with a long-term thermal storage capability has been built up at the University of Calabria. In this paper it
is described the control and data acquisition system for the operation of the plant. Some considerations on the control's
schedule of the plant are developed.
Riassunto Si descrive un sistema di controllo e acquisizione dati a basso costo ed elevata affidabilità per la gestione di un impianto solare dotato di accumulo di calore a lungo termine.相似文献
87.
We show that self-transparent or gap solitons with leading-order components at fundamental frequency can be generated in a singly resonant Bragg grating by second-harmonic generation. We discuss the conditions required for exciting these localized waves. 相似文献
88.
The apparent molar heat capacity, C
p,, of aqueous NaOH has been measured at temperatures between 50 and 250°C and molalities from 0.05 to 1.5 mol-kg–1. Enthalpies of dilution L were also determined at 99°C and apparent molar relative enthalpies L were calculated up to 1.9 m. Measurements were performed by means of a flow calorimetric apparatus constructed in our laboratory and standardized for C
p, and L with aqueous Na2SO4 and with the formation of water from its ions, respectively. Characteristics and performance of this calorimeter are described in detail. Pitzer's semiempirical equations are used for the representation of the results and a general fitting of C
p, data is reported using also recent literature values measured between 4 and 55°C. The fitted parameters are finally utilized, through an integration procedure, to derive a general equation to calculate L at any temperature between 4 and 250°C. 相似文献
89.
Zaramella A Conti N Dal Cin M Paio A Seneci P Gehanne S 《Journal of combinatorial chemistry》2001,3(5):410-420
The presence of dansyl or dabsyl chromogenic moieties in a solid-phase analytical construct, an assembly of linkers/spacers/sensitizers for improving analytical characterization, allows the accurate estimation of products from solid-phase synthesis by UV detection during liquid chromatography-mass spectrometry analysis in the cleavage solution. The spectroscopic properties of dansylated molecules have been evaluated to verify the "compound-independent UV absorption" necessary for using the chromophore in the accurate estimation. First, measurements on commercial dansylated compounds were made, then a series of construct-like molecules were prepared by solution-phase synthetic procedures and their UV properties were determined. Compound calibration curves were determined, and UV absorption was shown to be both proportional to the compound concentration and compound-independent. An example of a dansyl construct derivative was then prepared on a polymeric matrix, and an accurate estimation using the calibration curves was carried out in the cleavage solution. Good agreement was found between the calculated amount of released compound using the UV calibration curves and the calculated amount using both (1)H NMR and LC/chemiluminescent nitrogen detection quantitative techniques. Preliminary studies using the dabsyl moiety as an improved chromophore with higher wavelength and extinction coefficient are also reported. 相似文献
90.