First principles study of point defects in titanium oxycarbide

We have performed first principles density functional theory calculations to study the formation energy of point defects in TiC, TiO and TiCO compounds. The formation energy of isolated vacancies were obtained for different equilibrium conditions. For binary compounds, we have also calculated the formation energy of antisite defects. It was found that the defect formation energies strongly depend on the chemical environment. Our results show that C vacancies are easily formed in TiC and TiCO. For the TiO compound, Ti vacancies are highly probable to occur and O vacancies are also easily formed under titanium rich atmosphere.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – CONC-REEQ/443/EEI/2005, POCTI/CTM/69362/200

Entwurfsautomatisierung für HF-Schaltungen für Mobilfunk-Transceiver

This thesis proposes an automated design technique for key building blocks in RF clock generation subsystems, addressing the blocks' high-speed and low power requirements. Furthermore, a methodology for automated phase noise aware-design of RF clock distribution circuits utilizing a commercial digital design toolchain is proposed. The methodology provides a rapid approach for phase noise estimation, a buffer insertion and gate sizing algorithms operating under phase noise constraints.Diese Dissertation behandelt die Automatisierung des Entwurfs wichtiger Komponenten für die Erzeugung der Taktsignale in HF-Schaltungen. Dabei liegt der Fokus auf den Geschwindigkeitsanforderungen und dem niedrigen Stromverbrauch der Komponenten. Darüber hinaus wird eine Methodik für den automatisierten Entwurf von HF-Taktverteilungsschaltungen unter Berücksichtigung des Phasenrauschens vorgeschlagen. Diese Methodik basiert auf industriell gebräuchlichen Entwurfswerkzeugen. Sie ermöglicht eine schnelle und dennoch genaue Schätzung des Phasenrauschens. Weitere Algorithmen bestimmen den Einbau von Puffern sowie die Gatterdimensionierung zur Reduktion des Phasenrauschens

Rezultati ispitivanja temperature solarnih modula

A research was made on the influence of the temperature of stationary photovoltaic modules on the production of electricity. The modules are connected in groups, with a total maximum installed capacity of 117.24 kWp. They are mounted on the roof of a non-residential building, located in an uninhabited area. The study covers several typical months in the period from January 2009 to December 2012. The produced electricity changes in the interval 0 - 25.55kWh, for a temperature difference between the photovoltaic modules and the environment in the range of -5 to +30° C.Prikazani su rezultati istraživanja uticaja temperature stacionarnih fotonaponskih modula na proizvodnju energije. Moduli su povezani u grupe, sa ukupnim maksimalnim instalisanim kapacitetom od 117.24 kWp. Postavljeni su na krov zgrade u nenaseljenom području. Istraživanje je izvedeno tokom nekoliko tipičnih meseci, u periodu januar 2009 - decembar 2012. Proizvedena električna energija se menja u intervalu 0 - 25.55 kWh, za temperatursku razliku između fotonaponskih modula i okoline u intervalu od -5 do +30°C