Porous silicon samples were prepared by electrochemical etching method for different etching times. The structural properties of porous silicon (PS) samples were determined from the Atomic Force Microscopy (AFM) measurements. The surface mean root square roughness (σ rms) changes as function of porosity were studied, and the influence of etching time on porosity and roughness was studied too. U...

Avila and Molina [1] introduced the notion of generalized weak structures which naturally generalize minimal structures, generalized topologies and weak structures and the structures α(g),π(g),σ(g) and β(g). This work is a further investigation of generalized weak structures due to Avila and Molina. Further we introduce the structures ro(g) and rc(g) and study the properties of the structures r...

A signed graph (G,σ) on n vertices is called a parity if there bijection f:V(G)→{1,2,…,n} such that for each edge e=uv of G, f(u) and f(v) have the same σ(e)=1, opposite parities σ(e)=−1. The signature σ parity-signature G. Let Σ−(G) denote set number negative edges over all possible parity-signatures σ. rna σ−(G) G given by σ−(G)=minΣ−(G). In other words, minimum cardinality an edge-cut in two...