Search results for " DIP"

Il restauro di due delle tavolette “fuori posto” “Abbraccio di due Amanti” e “Drôlerie “ provenienti dal soffitto ligneo dell’Aula Magna dello Steri …

2015

Le Tavolette fuori posto sono un unicum di quattro dipinti su tavola, oggi di proprietà della Galleria Interdisciplinare Regionale di Palazzo Abatellis di Palermo. Nell’ambito di questo lavoro, eseguito per una tesi di laurea del CdLM in Conservazione e Restauro dei BB.CC. dell’Università di Palermo [1], è stato condotto uno studio approfondito su queste quattro opere sia dal punto di vista storico-artistico che scientifico per conoscere la tecnica esecutiva ed i materiali posti in opera, lo stato di conservazione e per verificare l’ipotesi di appartenenza al soffitto ligneo dell’Aula Magna dello Steri di Palermo. La campagna di diagnostica è stata propedeutica al restauro per indirizzare l…

Substituent effects of1H NMR parameters of chlorinated diphenyl ethers. A statistical approach

1994

The 1H NMR spectra of 64 polychlorinated diphenyl ethers (PCDEs) were measured and assigned. Multiple linear regression analysis was used to estimate the effects of chlorine atoms on the 1H NMR chemical shifts and coupling constants. The ‘simple sum rules’ were found to be inadequate for the prediction of 1H NMR chemical shifts of PCDEs. Therefore, corrective terms of two chlorine atoms were taken into account. The most important effects on chemical shifts were shown to be the steric interactions of two adjacent chlorine atoms and the intramolecular ring current effect observed in the ortho-proton of tri-ortho-substituted PCDEs. The substituent effects on J(HH) coupling constants were found…

Substituent effects on13C NMR parameters of chlorinated diphenyl ethers. A multiple linear regression analysis

1995

13C NMR chemical shifts and nJ(C,H) coupling constants of polychlorinated diphenyl ethers (PCDEs) were measured and analysed. The chlorine substituent effects on the chemical shifts and the coupling constants were determined by a multiple linear regression analysis. The 13C NMR chemical shifts depend on the conformational preferences in PCDEs. In addition to single substituent effects, corrective terms reflecting the conformational state of the molecule and the mutual steric interactions of two chlorine atoms had to be taken into account for the reliable prediction of the 13C chemical shifts. In contrast to chemical shifts, conformational effects play a minor role in the substituent effects…

Benzyl ions from 1,1-(2,2′-dimethoxyphenyl)-substituted 2-methylpropanes under electron ionization

2006

The electron ionization (EI)-induced fragmentations of a series of 1,1-(2,2'-dimethoxyphenyl)-substituted 2-methylpropanes (1-20) in both 70 eV and mass-analyzed ion kinetic energy (MIKE) spectra have been investigated. The EI-MS spectra of these compounds are characterized by the presence of abundant benzyl ions. These ions result from competitive hydrogen migration from the 2- and 2'-methoxy groups on the carbenium center of the diphenylmethyl cations formed by benzylic cleavage of the molecular ions. The relative abundances of the benzyl ions arising from such competitive processes are discussed and rationalized. The steric effect of the 3- or 3'-substituents is the main discriminating f…

Ancora "litterae" prestampate nell'età degli incunaboli

2009

Irene Mellis - dabaszinātņu pētniece, publiciste un sekretāre

2022

Latvijas Universitātes studenti, ar kuriem lepojamies, ir veicinājuši zinātnes, latviešu kultūras un dzīvesziņas uzturēšanu savās mītnes zemēs. Irene Mellis (dzim. Putniņa) (1916-2017) ir viena no Latvijas Universitātes (LU) Matemātikas un dabaszinātņu fakultātes absolventēm, kura sekmīgi aizstāvot maģistra darbu “Rembates dolomītsmilšakmens kvantitatīvais minerāloģiskais sastāvs : mēģinājums novērtēt ģeometriskās analīzes noderību iežu uzbūves raksturojumam“, studijas beidza 1944. gadā, bet sava mūža lielāko daļu kopā ar ģimeni pavadīja Zviedrijā. I. Mellis diplomdarbu ar “ ļoti sekmīgi” novērtējuši fakultātes mācību spēki B. Popovs, V. Zāns un N. Delle un tas ir pieejams LU Bibliotēkas kr…

The battle for Azerbaijan : Azeri Perspectives on the Observation of the 2005 Parliamentary Elections and the Post-Election Period

2006

- This report seeks to highlight the role of international observer missions of the 9 November 2005 parliamentary election in Azerbaijan. It also presents in-depth assessments of the pre- and post-election situation in the country. The six articles that are presented in the volume have been produced by leading scholars or development practitioners in Azerbaijan. The report forms part of the ‘Network for Election Observation and Exchange’. This is project that is supported by the Norwegian Ministry of Foreign Affairs.

Incorporation of ATP synthetase into long-term stable liposomes of a polymerizable synthetic sulfolipid

1981

Temperature dependence of the magnetic Casimir-Polder interaction

2009

We analyze the magnetic dipole contribution to atom-surface dispersion forces. Unlike its electrical counterpart, it involves small transition frequencies that are comparable to thermal energy scales. A significant temperature dependence is found near surfaces with a nonzero DC conductivity, leading to a strong suppression of the dispersion force at T > 0. We use thermal response theory for the surface material and discuss both normal metals and superconductors. The asymptotes of the free energy of interaction and of the entropy are calculated analytically over a large range of distances. Near a superconductor, the onset of dissipation at the phase transition strongly changes the interac…

A molecular dynamics study of large-scale reversible aggregation of anisotropic particles

1992

We report findings of 1000 ps molecular dynamics simulations of a bidimensional system of 4050 Lennard–Jones particles with electric dipoles, undergoing spinodal separation. This simple system is used to model the reversible aggregation of building blocks bearing specific and fixed adhesion sites at their surface. Aggregation regions so obtained resemble images of self-assembled biological structures. Statistical analyses of these regions evidence the interplay of thermodynamic instability and of interaction range between the attachment sites. They also illustrate some basic aspects of the morphogenesis of extended biomolecular/cellular structures, self-organized from initially homogeneous …