In this article we introduce the notion of n-capable groups. It is shown that every group G admits a uniquely determined subgroup (〖Z^n)〗^* (G) which is a characteristic subgroup and lies in the n-centre subgroup of the group G. This is the smallest subgroup of G whose factor group is n-capable. Moreover, some properties of n-central extension will be studied.

in the present work, structural characteristics and tribological properties of the ti-al-cr-(si)-c-n nanocomposite films coated on the spk 1.2080 tool steel bypvd technique have been investigated. the pvd coating process was carried out using ti (si) al and cral cathodes at 150 a current, 40 v bias and (ar)0.1(ch4)0.45(n2)0.45 gas mixture for 50 min. evaluations were conducted by om, fesem, afm...

in order to evaluate the effect of nitrogen absorption and use efficiency in relay intercropping for winter wheat and maize, a field experiment was conducted during 2008-2009 at the agricultural research station of ferdowsi university of mashhad, iran. a randomized block design with three replications was used. treatments included four combinations of relay intercropping of wheat and maize (thr...

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τ e , τ h electron & hole minority carrier lifetimes respectively L e , L h electron & hole minority carrier diffusion lengths respectively µ e , µ h electron & hole mobilities respectively (cm 2 /V-sec) D e , D h electron & hole diffusivities respectively (cm 2 /sec) n e , n h the electron & hole concentrations respectively n e0 , n h0 electron & hole concentrations in thermal equilibrium n i ...

The visceral storage fat and liver of patin catfish (Pangasianodon hypophthalmus) are normally discarded, which incurs cost and can cause environmental pollution. However, these may be potential sources to extract fish oil. The proximate and fatty acid compositions of liver and fatty tissue of patin catfish were investigated to evaluate the suitability of these by-products for extracting fish o...

The visceral storage fat and liver of patin catfish (Pangasianodon hypophthalmus) are normally discarded, which incurs cost and can cause environmental pollution. However, these may be potential sources to extract fish oil. The proximate and fatty acid compositions of liver and fatty tissue of patin catfish were investigated to evaluate the suitability of these by-products for extracting fish o...

In the present work, we investigated and optimized the digestion efficiency, A/S (Al2O3/SiO2 in red mud), and N/S (Na2O/SiO2 in red mud) of mixed bauxite in Iran Alumina Company using the Bayer process. Digestion experiments were carried out in an induction rotary autoclave on a mix of Jajarm, Yazd, Tash, and Shirin Cheshmeh baux...