objective:  the aim of the present study was to evaluate the effect of two impression materials on the shear bond strength of porcelain to immediately sealed dentin. materials and methods: smooth dentin surfaces of 45 extracted premolars were immediately sealed with adper single bond adhesive agent. forty-five porcelain specimens were also prepared. the teeth were divided into one control and t...

The growth mechanisms of small cationic silicon clusters containing up to 11 Si atoms, exohedrally doped by V and Cu atoms, are described. We find that as dopants, V and Cu follow two different paths: while V prefers substitution of a silicon atom in a highly coordinated position of the cationic bare silicon clusters, Cu favors adsorption to the neutral or cationic bare clusters in a lower coor...

  Three different materials (aluminum, ferro -silicon and silicon) were used as antioxidants in order to prevent the decarburization process and to keep and/or increase the final properties in MgO-C refractories. Their effects were compared by measuring the physical and mechanical properties as well as oxidation and the resultant phases and microstructures, in the temperature range of 200-1600 ...

The thermal characteristics of SiC/Si samples obtained by the method coordinated substitution atoms at different thicknesses SiC have been experimentally investigated. It has found that for less than 200 nm, resistance is approximately equal to 2 K/W, which coincides with a pure silicon substrate. Such will perfectly remove heat from light-emitting heterostructure grown on SiC/Si. With an incre...

Abstract Aluminum alloys commonly contain Si as an impurity or alloying element. The energetic behavior of within multiple compounds and solutions is incorporated inside thermochemical packages, such FactSage. This tool allows determining the partitioning complex multiphasic systems. Recent experimental research suggests that can be found Al 3 Zr-based intermetallics. Nevertheless, current Fact...

this study is about complexes of li doped silicon carbide nanotube with thymine and cytosine ingas phase and aqueous solutions. li doped silicon carbide nanotube and its pyrimidine nucleobasecompounds were first modeled by quantum mechanical calculations in gas phase and in water.calculated binding energies indicated the stronger ability of thymine to functionalize silicon carbidenanotube than ...

silicon (si) is considered as one of the beneficial elements for plants that play important roles in plant resistance to stresses. in this experiment, the effects of three levels of silicon (0, 0.85 and 1.7 mm) on the growth and physiological processes of pumpkin were studied in plants inoculated with sphaerotheca fuliginea (250000 conidia ml−1) and non-inoculated plants under hydroponic condit...