The electrical and structural properties of Hf/Al/Ni/Au (20/100/25/50 nm) ohmic contact to n-GaN are reported in this study. Specific contact resistivities of Hf/Al/Ni/Au based contacts have been investigated as a function of annealing temperature and achieve the lowest value of 1.09×10 Ω·cm after annealing at 650 C in vacuum. A detailed mechanism of ohmic contact formation is discussed. By usi...

cu-mo and cu-ti contact structures were fabricated on multi-crystalline silicon substrates to provide a low resistance ohmic contact. deposition steps are done in an excellent vacuum chamber by means of electron beam evaporation and samples are then annealed for the realization of an efficient alloy layer. the effects of process parameters such as film thickness, annealing duration and temperat...

We propose a discrete model to investigate the role of contact tracing program reducing the newcases and prevalence of tuberculosis. We observe that the tuberculosis contact tracing program has no effect on the basic reproduction number R0 but the size of social cluster has. On the other hand a contact tracing program can speed up the process of TB elimination. We compute the partial rank corre...

A solution is presented to a doubly mixed boundary value problem of the torsion of an elastic layer, partially resting on a rigid circular base by a circular rigid punch attached to its surface. This problem is reduced to a system of dual integral equations using the Boussinesq stress functions and the Hankel integral transforms. With the help of the Gegenbauer expansion formula of the Bessel f...

Many cities in the Global South are structurally different from Northern, particularly American, on which much of urban sociology’s conceptual apparatus has been based. Thus, depicting them terms a standard vocabulary risks imposing an inappropriate way seeing. We need that is able to accommodate their experience. This special issue contributes work building vocabulary. select five keywords soc...

When stuck-at faults are targeted, scan design reduces the complexity of the test problem. But for delay fault testing, the standard scan structures are not so efficient, because delay fault testing requires the application of dedicated consecutive two-pattern tests. In a standard scan environment, pre-determined two pattern tests cannot be applied to the circuit under test because of the seria...

This paper describes a new algorithm for determining all discrete contact symmetries of any differential equation whose Lie contact symmetries are known. The method is constructive and is easy to use. It is based upon the observation that the adjoint action of any contact symmetry is an automorphism of the Lie algebra of generators of Lie contact symmetries. Consequently, all contact symmetries...

abstract:any effects of wood coating with different compounds as nano-zinc, nano-chitosan, chitosan, silicon oil and flaxseed oil on surface properties as; wood color change, surface roughness and wettability were studied in the current research work. for this purpose, sample boards of beech wood were cut into sizes of 2×10×20cm. the specimens were coated with the noticed coatings and tested fo...