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21.
A (k,k)-current T on an open subset of CN is plurisubharmonic if is positive. Positive plurisubharmonic currents admit Lelong numbers; we prove here that they are independent on the coordinates system. Moreover, if Y is an analytic subset of pure dimension, then the Lelong numbers of T on Y are given by a non negative weakly plurisubharmonic function. 相似文献
22.
R. Ficarra M. L. Calabrò S. Tommasini D. Costantino M. Carulli S. Melardi M. R. Di Bella F. Casuscelli R. Romeo P. Ficarra 《Chromatographia》1996,43(7-8):365-368
Summary A high-performance liquid chromatographic method is reported for the resolution of the enantiomers of a series of fused -lactams (2,7-diaza-3-oxo[3.3.0]octan-6-ones) with probable anti-HIV and anticancer activity. Resolution was achieved on a Chiralcel® OD column, cellulose tris-(3,5-dimethylphenyl carbamate) adsorbed on macroporous silica gel; mixtures ofn-hexane and isopropyl alcohol in different proportions were used as the mobile phase. The analysis was studied at different temperatures. 相似文献
23.
A new method was developed for the determination of 2-furfural (2-F) and 5-methylfurfural (5-MF), two products of Maillard reaction in vinegar, with head-space solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). A divinylbenzene (DVB)/carboxen (CAR)/polydimethylsiloxane (PDMS) fibre was used and SPME conditions were optimised, studying ionic strength effect, temperature effect and adsorption time. Both analytes were determined by calibration established on 2-furfural-d4 (2-F-d4). The method showed good linearity in the range studied (from 16 to 0.12 mg/l), with a regression coefficient r2 of 0.9999. Inter-batch precision and accuracy were found between 14.9 and 6.0% and between -11.7 and 0.2%, respectively. Detection limit was 15 microg/l. The method is simple and accurate and it has been applied to a series of balsamic and non-balsamic vinegars. 相似文献
24.
A classical theory of dissociative attachment (DA) is developed. The DA cross section σν → DA of a molecule in the initial vibrational state ν is calculated. The model is applied to the negative ion formation in low energy electron scattering from CF3Cl molecules. Temperature effects of the DA cross section of CF3Cl can be explained within our classical model. 相似文献
25.
Diffusion, density, and viscosity data are collected for the systems -cyclodextrin and -cyclodextrin in water. Frictional coefficients were computed with the help of literature activity data and a qualitative discussion of their concentration dependence was attempted. 相似文献
26.
Guarise C Pasquato L Scrimin P 《Langmuir : the ACS journal of surfaces and colloids》2005,21(12):5537-5541
Aqueous solutions of Au colloids (12 +/- 4 nm size) when treated with a blend of mono- and dithiols aggregate forming stable clusters, as evidenced by the shift of their surface plasmon (SP) band from 512 to ca. 600 nm. The presence of carboxylate ester functions on the dithiol allows its cleavage by addition of a cleaving agent, such as hydrazine. The cleavage process results in the breaking down of the clusters of nanoparticles and the shift of the SP band back to lower wavelengths. Further addition of dithiol causes the formation of the clusters again. The aggregation/deaggregation process may be monitored visually by following the color change from pink-red to purple and vice versa in the forward and backward steps, respectively. 相似文献
27.
28.
2-Amino-5-alkyl and 2-amino-5-aryl-1,3,4-thiadiazoles were prepared by the dehydration of 2-acylthiosemicarbazides with molar equivalents of methanesulfonic acid in refluxing toluene. The synthesis appears to be general. 相似文献
29.
Ortona O D'Errico G Vitagliano V Costantino L 《Journal of colloid and interface science》2002,249(2):481-488
Apparent molar relative enthalpies were measured for the nonionic ethoxylated surfactant CH(3)-(CH(2))(5)-(OCH(2)-CH(2))(5)OH (C(6)E(5)) in aqueous solution at constant molality of the ionic surfactant CH(3)-(CH(2))(5)-SO(-)(3)Na(+)(C(6)SNa) at 25 degrees C. The experimental data obtained by a stepwise dilution process allowed evaluation of the C(6)E(5) first interaction parameter at several constant molalities of C(6)SNa. The C(6)E(5) critical micelle composition as a function of the C(6)SNa molality was also estimated. The experimental calorimetric data, together with the mixed micelles composition computed in the past by some of us [Ciccarelli et al., Langmuir 14, 7130 (1998)], allowed computation of the Deltah(Mic) of micellization. The experimental data are compared to those predicted by the ideal solution model and regular solution model of mixed micellization. From a calorimetric study performed on the water-hexanol-C(6)SNa and water-penthaethylene glycol-C(6)SNa model systems, it can be argued that the interactions among the hydrophilic heads in the C(6)E(5)-C(6)SNa mixed micelles prevail on the contribution of the hydrophobic tails in ruling the enthalpic properties of the system. 相似文献
30.
Hans-Jürgen?BuschmannEmail author Lucia?Mutihac Eckhard?Schollmeyer 《Journal of inclusion phenomena and macrocyclic chemistry》2005,51(1-2):53-57
The formation of complexes between α-cyclodextrin and n-alkylamines and their hydrochlorides has been studied in aqueous solution using calorimetric titrations. All alkylamines form stronger complexes than the corresponding hydrochlorides. The values of the reaction enthalpies are smaller for the alkylamine hydrochlorides compared with the alkylamines. By increasing the number of methylene groups, these differences become smaller. In addition, the reaction enthalpies for protonation of the alkylamines and their complexes with α-cyclodextrin have been measured. The heat of protonation of these complexes is always smaller compared with the alkylamines. Due to the protonation and the formation of a strong solvation shell around the ammonium group the interactions with α-cyclodextrins are weakened. From a thermodynamic cycle using all measured reactions, it can be concluded that the aggregation of the alkylamines with long alkyl chains (heptyl-, octyl-, and nonylamine) has an influence on the values of the reaction enthalpies and entropies for the protonated form only.This revised version was published online in July 2005 with a corrected issue number. 相似文献