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The research from this project has quantified the solar UV environment beneath and surrounding typical local council public shade structures. The effects of changing seasons, atmospheric conditions, structural modifications and surrounding plant life on diffuse UV have been quantified. Strategies to improve current shade structures, so as to significantly reduce the levels of diffuse UV reaching the human body in the shade, have also been developed. For the shade structures used in this research it was found that ultraviolet protection factors ranged from 1.5 to 18.3 for a decreasing solar zenith angle. Correlations have been found relating diffuse erythemal UV to UV in the shade for clear skies and a changing solar zenith angle. The effect of changing atmospheric ozone levels on diffuse erythemal UV levels has been quantified. UV exposures were assessed for a decrease in scattered UV beneath specific shade structures by the use of two types of protection, namely, side-on polycarbonate sheeting and evergreen vegetation. Broadband radiometric and dosimetric measurements conducted in the shade of a scale model shade structure, during summer and winter, showed significant decreases in exposure of up to 65% for summer and 57% for winter when comparing the use and non-use of polycarbonate sheeting. Measurements conducted in the shade of four shade structures, with various amounts of vegetation blocking different sides, showed that adequate amounts and positioning of vegetation decreased the scattered UV in the shade by up to 89% when compared to the shade structure that had no surrounding vegetation. This research shows that major UV reduction could be achieved by the ‘shade creation and design industry’, and that shade guidelines should be updated as soon as possible.

Depuis leurs découvertes dans les années 60 par Dewar, les composés BN-hétérocycliques ont subi un développement croissant, s’accentuant pendant la dernière décennie. Ce travail de thèse mené en collaboration avec le Pr S-Y LIU de Boston Collège (États-Unis) et le Pr L. WEBER de l’Université de Bielefeld (Allemagne), a permis la synthèse, ainsi que la caractérisation par spectroscopie photoélectronique à rayonnement UV de nouveaux systèmes. Dans une première partie représentée par les chapitres II, III et IV, nous abordons l’étude de la structure électronique des composés suivants : 1,2-dihydro-1,2-azaborine (1), N-Me-1,2-BN-toluene (2), N-Me-1,3-BN-toluene (3), 1,2-dihydro-1-aza-2-boranaphtalene (4), 1,2-dihydro-1-aza-2-boranthracene (5), 1,2-dihydro-1-aza-2-boranthracene (6), 1,2-dihydro-1-aza-2-boraphenanthrene (7), 1,3,2-benzodiazaborole (8), 1,9,8-benzodiazaborole (9), N-tert-butyl[1,3,2]diazaborolo[1,5-a]-pyridine (10), 1,3,2-trihydro[1,3,2]diazaborolo[1,5-a]-pyridine (11). Afin de compléter les propriétés physico-chimiques de ces nouveaux systèmes et d’aider à l’interprétation des spectres photoélectroniques, l’utilisation de calculs quantiques tels que la théorie de la fonctionnelle de la densité (DFT), la théorie fonctionnelle de la densité en fonction du temps (TD-DFT), la fonction de Green (OVGF), la méthode du troisième ordre partiel (P3), ou encore l’interaction de configuration (SAC-CI) ont été utilisées. Dans le Chapitre V, nous présentons une étude comparative entre les énergies ionisations théoriques et expérimentales. / Since the Dewar’s discovering in 60 years, the BN-heterocycles has experienced an important development during the last decade. This thesis presents our work on the synthesis and on the electronic structure characterization by Ultra-Violet photoelectron spectroscopy (UV-PES), followed in collaboration with the Pr SY LIU from the Boston College (USA) and the Pr L. WEBER from the University of Bielefeld (Germany). The first part corresponding to the chapter II, III and IV, describe the electronic structure analysis of: 1,2-dihydro-1,2-azaborine (1), N-Me-1,2-BN-toluene (2), N-Me-1,3-BN-toluene (3), 1,2-dihydro-1-aza-2-boranaphtalene (4), 1,2-dihydro-1-aza-2-boranthracene (5), 1,2-dihydro-1-aza-2-boranthracene (6), 1,2-dihydro-1-aza-2-boraphenanthrene (7), 1,3,2-benzodiazaborole (8), 1,9,8-benzodiazaborole (9), N-tert-butyl[1,3,2]diazaborolo[1,5-a]-pyridine (10), 1,3,2-trihydro[1,3,2]diazaborolo[1,5-a]-pyridine (11). In order to provide more information on the physical chemistry properties and to interpret the photoelectron spectra, the quantum chemical calculations of ionization energies have been followed using the Density Functional Theory (DFT), the Time-Dependent Density Functional Theory (TD-DFT), the Outer Valence Green’s Function (OVGF), the Partial third order (P3), the Symmetry Adapted Cluster-Configuration Interaction (SAC-CI). Moreover, the comparative analysis of theoretical and the experimental ionization energies are presented.