Simple approach to include external resistances in the Monte Carlo simulation of MESFETs and HEMTs

The contact and external series resistances play an important role in the performance of modern 0.1-0.2 μm HEMT's. It is not possible to include these resistances directly into the Monte Carlo simulations. Here we describe a simple and efficient way to include the external series resistances into the Monte Carlo results of the intrinsic device simulations. Examples of simulation results are given for a 0.2 μm pseudomorphic HEMT

The role of Climate in affecting energy demand/supply in the State of Qatar

The study attempts to investigate the impact of Climatic factors on the present and future energy demand/supply in the State of Qatar. The effects of climatic parameters such as temperature, humidity and wind on electric energy consumption and the contamination of its distribution systems were analysed. The possibilities of using solar insulation and wind to generate power were also discussed. It was found that daily and seasonal temperature distribution greatly affect electric energy supply, and that maintenance cost is high due to the pollution caused by the weather elements. The potential use of renewable solar energy and wind power in the State of Qatar is great given that reliable and cost effective systems are developed

The vegetation of the state of Qatar as related to landform and soil.

The effect of landform and soil on the vegetation of the State of Qatar is described. Five major landform/soil subdivisions are recognized; depressions, wadis, rocky and conglomerate hammada surfaces, sand dunes and sabkhas. The vegetation was sampled and relative importance, diversity values and similarity indices were estimated. Soil samples were analysed. Depressions have the richest and most diversified plant cover. On the other hand sand dunes have very poor vegetation cover. Sabkhas have simple and less diversified flora. The five landform/soil subdivisions show great differences in diversity and degrees of similarity. Differences in soil physical and chemical properties enhanced by landform variations are probably the major factor involved

Monte Carlo investigation of optimal device architectures for SiGe FETs

Strained silicon channel FETs grown on virtual SiGe substrates show clear potential for RF applications, in a material system compatible with silicon VLSI. However, the optimisation of practical RF devices requires some care. 0.1-0.12 μm gate length designs are investigated using Monte Carlo techniques. Although structures based on III-V experience show fT values of up to 94 GHz, more realistic designs are shown to be limited by parallel conduction and ill constrained effective channel lengths. Aggressively scaled SiGe devices, following state-of-the-art CMOS technologies, show fT values of up to 80 GHz

Effect of Sowing Date and Intra-Row Spacing on Growth and Yield of Groundnut at El Rahad Agricultural Scheme

The effects of sowing date and intra-row spacing on growth and yield of groundnut (Arachis hypogaea L.) were evaluated over a 3- year period in the irrigated Rahad Scheme. The main effects of sowing date and intra-row spacing were significant but their interactions were not. Late sowing in August and September resulted in small plants with fewer pods, low biological and pod yields due to their development under the low temperatures of November, December and January. On the other hand, high number of pods was produced per plant at wide intra-row spacing but most of the pods were immature with poor shelling percentage and low 100-seed weight. This was attributed to the uneven maturity of groundnut at harvest where pods were initiated over a longer period of time particularly in the low plant population. Early sowing (June) and the high plant population (250000 plants/ ha) proved to be essential package components for the alternately branched variety (MH383) under irrigated vertisol of El Rahad Agricultural Scheme

Strain engineered In_xGa_1-xAs channel pHEMTs on virtual substrates: a simulation study

The impact of In<sub>x</sub>Al<sub>1-x</sub>As strain control buffers on the performance of low In content InGaAs channel pseudomorphic high electron mobility transistor p(HEMT) is investigated. It is shown that relaxed and tensile strained channel devices outperform the conventional compressively strained channel devices. It is argued that strain engineering in GaAs based devices makes it possible to realise RF characteristics comparable to InP based pHEMTs while obtaining improved breakdown characteristics

RF performance of strained Si MODFETs and MOSFETs on "virtual" SiGe substrates: A Monte Carlo study

No abstract avaliable

Effect of Plant Density and Spatial Arrangement on Growth, Quality and Yield of Morphologically Varying Cotton Varieties

Field experiments were conducted at Rahad Research Station for two seasons (2000/2001 and 2001/2002) focusing on how the vari- ation in genotypes, plant density and spatial arrangement affects cotton yield and quality . The combined analysis indicated significant responses due to main effects but their interactions were not. Regr- ession analysis for plant density-yield response curve exhibited a curvilinear relationship with the highest seed cotton yield (3895 kg/ha(. achieved at 125000 plants/ha and thereafter started to decrease. Such an optimum density was achieved by planting 3 plants/hill spaced at 30cm intra-row spacing. On average, Acala (93)H out-yielded Barac (67)B and Sudac-K by 22% and 59%, respectively. Sticky cotton due to honeydew secretions was thermodetectly measured, with sticky spots for Acala 93H, Barac(67)B and Sudac-K being in the ranges of 6-40, 4-22  and 0-12, respectively. Yet ,for each variety, the sticky spots range increased concomitantly with the increase in planting density. This was discussed in relation to variability in variety specific traits such as hairiness, glabrousness and plant canopy architecture. Nevertheless, these values were dramatically lower than those recorded internationally for the Sudan Cotton. Days to the last pick were 130, 170 and 185 for Sudac-K, and Acala (93)H, respectively. Accordingly, Sudac-K which is an early maturing, super- okra-leaf (SOL), highly resistant to whiteflies(Bemisia tabaci) but of comparatively low yield, emerged as a suitable choice for a short duration low management system where problems of late irrigation and build up of whiteflies are anticipated. Conversely, Acala (93)H (Nour 93), being hairy, physiologically efficient in compensating for yield losses due to late adversities and with stay green character is best fitted into long season high management strategy