Optimum transit angles of millimeter-wave Si IMPATT diodes
Optimum transit angles for maximum output power in the millimeter-wave IMPATT diodes are calculated analytically by considering the carrier diffusion process through the space-charge region. It is found that the optimum transit angle decreases, as the space-charge layer width reduces. The theoretical results show satisfactory agreement with the previously published experimental results for Si p+-n-n+abrupt junction diodes.
Ion-implanted complementary IMPATT diodes for D-band
Complementary silicon single-drift-region IMPATT diodes designed to operate above 100 GHz have been fabricated with ion-implanted dopant profiles. Continuous-wave output powers of 140 mW with 2.8-percent conversion efficiencies were obtained at 142 GHz.
Heritage Sites of Astronomy and Archaeoastronomy in the context of the UNESCO World Heritage Convention: A Thematic Study
"Following the publication of the first ICOMOS–IAU Thematic Study (“TS1”) in 2010, the IAU requested its Working Group on Astronomy and World Heritage to develop particular case studies in greater detail, so as to explore further and clarify some of the key issues highlighted in TS1 that can arise in the particular case of astronomical heritage sites. In doing so, it would further encourage and aid State Parties in the development of nominations. In collaboration with ICOMOS, nine “extended case studies” were duly prepared for discussion at a workshop held at Mount Cook, New Zealand, in June 2012 and presented at the IAU General Assembly in August of that year. 
 
A particularly complex issue is the recognition and protection of dark skies. Dark sky areas cannot in themselves be considered as potential World Heritage Sites, but a thematic chapter by Michel Cotte considers a range of ways in which dark sky values can be interrelated with broader cultural or natural values of a place and thereby contribute to its overall cultural or natural value and potential OUV. Other issues explored in TS2 include the need to balance archaeoastronomical considerations in the context of broader archaeological and cultural values; the potential for serial nominations, for example among groups of monuments whose astronomical significance is only evident from the group as a whole; and management issues such as preserving the integrity of astronomical sightlines through the landscape. 
 
The case studies included in TS2 include seven-stone antas (prehistoric dolmens) in Portugal and Spain, the thirteen towers of Chankillo in Peru, the astronomical timing of irrigation in Oman, Pic du Midi de Bigorre Observatory in France, Baikonur Cosmodrome in Kazakhstan, and Aoraki–Mackenzie International Dark Sky Reserve in New Zealand. A case study on Stonehenge, already a World Heritage Site, focuses on preserving the integrity of the solstitial sightlines." 
 
Source: UNESCO portal to the heritage of astronomy