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 structur...

doing a piece of research on acquisition of second language phonetics theoretically will justify the exact stages of language trans- fer and further predicts the existence of systematicity and difficulty order (eckman, 2008). the present research is an attempt to provide new evidence for the efficacy of second language acquisition to devel- opmental stages of acquisition of phonological structu...

volumetric techniques were employed to study the adsorption of co2 on a purified multi-wall carbon nanotubes (mwnt’s) sample, as a mesoporous material, at isothermal conditions of 288, 293 and 298 k and pressures ranging from 30 to 150 kpa. langmuir, freundlich and sips equations were used to represent the isotherms. also the parameters of these fitted isotherm models have been determined. the ...

administrative regulations for water flow decrease distribution efficiency and effect the economical operation of irrigation networks. complications in distribution systems and the decrease in availability of water require study of the hydraulic performance of existing flow control structures. control systems designed by neyrpic (zayandeh rud network) and usbr (doroodzan network) were investiga...

In this paper various layered planar periodic structures which provide miniaturization of planar antennas are proposed and discussed. The proposed designs are based on two concepts, reactive impedance surfaces and complementary periodic structures. In the proposed structures, complementary periodic rings and slots are patterned on the intermediate boundaries of the dielectric layers. A patch an...

Flexibility is a concept associated with variable needs of human beings.Today transformable structures are used to meet human changeable demands with different purposes and functions such as facades, roofs, sunshades, etc.A Flexible structure must be able to change physically and adapt to predetermined conditions.To provide flexibility and adaptability,transformable systems are required to poss...

we study a new class of $h_v$-structures called fundamentally very thin. this is an extension of the well known class of the very thin hyperstructures. we present applications of these hyperstructures.

there are many efforts for identification of natural compounds from dietary or medicinal plants. young roots and aerial parts of a. persicus have been used as food additive or salad vegetable in some parts of iran. in this study, different fractions of the root extract of a. persicus were subjected for isolation and purification of secondary metabolites. the methanol extract of the roots was fr...