REVIEW OF ADVANCED IGBT COMPACT MODELS DEDICATED TO CIRCUIT SIMULATION

The paper aims to review the research area of the IGBT compact modelling and to introduce different device models. The models are separated in two groups, one that solves ambipolar diffusion equation (ADE) and one that does not. Both types of compact models have been successfully used in the past for power electronic circuit design

Nondestructive Method for Mapping Metal Contact Diffusion in In2O3 Thin-Film Transistors

The channel width-to-length ratio is an important transistor parameter for integrated circuit design. Contact diffusion into the channel during fabrication or operation alters the channel width and this important parameter. A novel methodology combining atomic force microscopy and scanning Kelvin probe microscopy (SKPM) with self-consistent modeling is developed for the nondestructive detection of contact diffusion on active devices. Scans of the surface potential are modeled using physically based Technology Computer Aided Design (TCAD) simulations when the transistor terminals are grounded and under biased conditions. The simulations also incorporate the tip geometry to investigate its effect on the measurements due to electrostatic tip–sample interactions. The method is particularly useful for semiconductor– and metal–semiconductor interfaces where the potential contrast resulting from dopant diffusion is below that usually detectable with scanning probe microscopy

PLANIRANJE I RAZVOJ ZELENIH POVRŠINA U GRADOVIMA: ANALIZA GENERALNIH URBANISTIČKIH PLANOVA GRADA NIŠA

Urban green areas have multiple roles in cities and to a large extent they determine the quality and livability of urban space. The process of urbanization has led to an increase in construction in cities and reduction of open public spaces, especially green areas. Planning of urban green areas is an integral part of urban planning, thus changes in planning and development of urban green areas can be observed through urban planning documents. The main question is whether the loss of green areas is a consequence of non-compliance with plans, or the reason for this lies in the method of planning of green areas. In order to answer this question the paper discusses: functions, standards and classification of urban green areas in general, and their use in two successive general urban plans of the city of Niš in the last twenty years, as a prerequisite for the development of green areas in accordance with growing need for green areas in the city.Zelene površine u gradovima imaju višestruku ulogu i u velikoj meri određuju kvalitet gradskog prostora i prijatnost za život. Proces urbanizacije doveo je do povećanja izgrađenosti u gradovima i smanjenja otvorenih javnih površina, naročito zelenih površina. Planiranje zelenih površina je sastavni deo urbanističkog planiranja, tako da se promene u planiranju zelenih površina i razvoj zelenih površina mogu platiti kroz urbanističke planove. Osnovno pitanje je da li je smanjivanje zelenih površina u gradovima posledica nepoštovanja urbanističkih planova ili razlog leži u samom načinu planiranja zelenih površina. Da bi se odgovorilo na to pitanje, rad se bavi funkcijama, normativima i klasifikacijom zelenih površina u gradovma i primenom ovih elemenata u dva generalna urbanistička plana grada Niša u poslednjih dvadeset godina, kao preduslovom za razvoj zelenih površina u skladu sa rastućom potrebom za zelenilom u gradovima.

PROSTORNA I FUNKCIONALNA STRUKTURA RURALNIH NASELJA U NIŠKIM OPŠTINAMA

Rural areas represent areas that are different from other areas in terms of economic, social, demographic and cultural development. The differences are determined by multiple factors - geomorphological characteristics, population, economic structure, infrastructure and utilities as well as the developmental potential of certain areas, all of which present the basis for the development of strategic plans. This paper discusses main characteristics of spatial and functional structure of rural areas situated within the municipalities of Niš. Many settlements, even when they stand next to each other, differ in terms of their inner organization and structure. But also, there are many elements that are common for the settlements in a certain area. The aim of this paper is to analyze functional and spatial structure of these settlements and to point out their similarities. Influence of the geographical location and historical background will be also analyzed. Because of their specific terrain conditions and due to the influence of historical events, these settlements had a very strong impact of Ottoman architecture and some of the evidence are present in their structure even today. On the other hand, because of their favorable location, air pollution is lower than in the cities which makes the quality of life better.Ruralne oblasti predstavljaju područja koja se razlikuju od ostalih područja u smislu ekonomskog, socijalnog, demografskog i kulturnog razvoja. Razlike određuje više faktora - geomorfološke karakteristike i populacija, ekonomska struktura, infrastruktura i komunalna opremljenost, kao i razvojni potencijal pojedinih područja koja su osnova za izradu strateških planova. U radu su razmatrane osnovne karakteristike prostorne i funkcionalne strukture u ruralnim područjima koja su u opštinama grada Niš. Mnoga naselja, čak iako su jedna pored drugih, razlikuju se u pogledu njihove unutrašnje organizacije i strukture, ali postoji veliki broj elemenata koji su zajednički za naselja u određenom području. Cilj ovog rada je da analizira funkcionalnu i prostornu strukturu ovih naselja i da ukaže na njihove sličnosti. Uticaj njihovog geografskog položaja kao i istorijska pozadina biće takođe analizirani u radu. Zbog svojih specifičnih uslova terena i zbog uticaja istorijskih događaja, ova naselja su imala vrlo jak uticaj Otomanske arhitekture, a neki od dokaza su i danas prisutni u njihovoj strukturi. S druge strane, zbog povoljnog položaja, nivo zagađenja vazduha je niži nego u gradovima što čini kvalitet života boljim

The study of effects of greenery on temperature reduction in urban areas

Urban landscape is largely characterized by high degree of built space, high share of artificial surface material and the reduction of green areas, which leads to changes in the microclimate and the deterioration of thermal comfort in out-door urban space. One of the most important roles of urban greenery is the impact on the reduction of air temperature due to less heating of green space com-pared to paved surfaces and due to tree shading. The paper analyses the influence of urban greenery on temperature reduction. Aim of the study was to measure the difference in warming up of grassy surfaces and paving materials commonly used for public areas and to evaluate the impact of tree shading on the surface cooling during the day. For this purpose, measuring of surface temperatures was performed during the summer months in 2015 in the central city zone of the city of Nis. The measuring included: grass, asphalt as most commonly used paving material, and concrete tiles commonly used for pedestrian areas. Results show the temperature of grass is significantly lower than the temperature of paved surface at any time of day. In the case of paved surfaces, temperature of shaded or partially shaded material is lower than the temperature of surface exposed to sunlight during the whole day, a temperature difference exists even after nocturnal cooling. The results indicate the importance of green areas for cooling of urban spaces, due to their lower warming and surface shading from tree canopy

Analysis of electric power production results in South Serbia: Recommendations for improvement of operation of first mini photovoltaic power plants

Solar radiation in Serbia is for about a third higher than in Middle Europe, which represents a very favorable energy potential. Southeast Serbia is a leading area in this aspect, since the annual average of daily global radiation on a horizontal surface exceeds 4.2 kWh/m2. This paper compares four photovoltaic power plants installed in southeastern Serbia. Analyzes are done based on results from two years of power plant exploitation. The power plants are not located in the same area – there are differences between topography and altitude of their locations, which is also taken into account during analyzes. Photovoltaic modules have different orientation and inclination toward horizontal surface, and their capacity varies from 30-40 kW. The conclusion provides recommendations for improvement of production where it is actually possible

Urban and architectural character of thermal ambient influences in operation of photovoltaic panels on buildings

This paper presents some basic urban and architectural requirements regarding the installation of solar panels for electricity production on buildings. These requirements are usually design ‒ aesthetic and functional ‒ constructive. However, from the thermal ambient aspect, constructor’s solution is often not in accordance with requirements of architectural and urban planning profession. It is a known fact that thermal environment impacts the yield in the solar panels production. The aim of this paper is to show, based on experience of solar power plant DOMIT, city of Leskovac, Serbia, what is the expected effect in that aspect, in order to choose the optimal solution with regard to the character of the building. The most favorable production have solar power plants built on buildings where the panels on the underside are completely open because they have the best ventilation, and therefore cooling