AIM The aim of this study was to evaluate the efficiency of several surface preparation methods for improving shear bond strength of brackets to demineralised enamel. MATERIALS AND METHODS STUDY DESIGN in vitro study. Eighty premolars were selected and divided into 5 groups. Group 1 served as the control, while the remaining 4 groups were immersed in a demineralising solution (pH 4.8) for ...

As the technology of VLSI manufacturing process continues to shrink, it becomes a challenging problem to generate layout patterns that can satisfy performance and manufacturability requirements. Wire width variation is one of the main issues that have a large impact on chip performance and yield loss. Particularly, etching process is the last and most influential process to wire width variation...

The aim of this in vitro study was to evaluate by scanning electron microscopy the morphological aspects of the enamel of primary teeth after etching with 36% phosphoric acid or a non-rinse conditioner. Ten naturally exfoliated anterior primary teeth were selected. The samples were subjected to prophylaxis with pumice paste and water using a low-speed hand piece. Etching was done on the buccal ...

OBJECTIVES This study aimed to evaluate the effect of chlorhexidine (CHX) application protocol on durability of marginal seal of class V composite restorations. MATERIALS AND METHODS Class V cavities (4×2×1.5mm) were prepared in the buccal surfaces of 160 human third molars. The teeth were randomly divided into five groups (n=32) of (G1) CHX+rinse+etching, (G2) CHX+etching, (G3) etching+CHX+r...

Oxidative etching of graphene flakes was observed to initiate from edges and the occasional defect sites in the basal plane, leading to reduced lateral size and a small number of etch pits. In contrast, etching of highly defective graphene oxide and its reduced form resulted in rapid homogeneous fracturing of the sheets into smaller pieces. On the basis of these observations, a slow and more co...

In the present study, a friction-induced selective etching method was developed to produce nanostructures on GaAs surface. Without any resist mask, the nanofabrication can be achieved by scratching and post-etching in sulfuric acid solution. The effects of the applied normal load and etching period on the formation of the nanostructure were studied. Results showed that the height of the nanostr...

Scanned beams of 0.1 MeV/u Au ions were employed for the bombardment of silicon oxide films thermally grown on silicon (1 0 0) substrates. Subsequently the films were etched in aqueous HF solution (1% and 4%) for various times and at different temperatures. Scanning force microscopy and transmission electron microscopy images of etched films reveal conical holes with diameters from 20 to 350 nm...

Etching of GaAs, when plasma of Ar gas is used and CF4 /O2 is directed fall on the wafer from another port in Electron Cyclotron Resonance (ECR) source in Chemically Assisted Ion Beam Etching (CAIBE) has been carried out. The plasma source was 2.45 GHz microwave source superimposed with mirror type magnetic field configuration to have resonance. Effect of CF4/O2/Ar ratio and substrate bias on e...

We report here on significant enhancement of the photochemical etching of p-type gallium phosphide (GaP) by Au plasmonic nanostructures. The photochemical etching rate of defect (dislocation) states of Au-coated p-GaP samples is ten times higher than blank samples when irradiated with 532 nm laser. It is confirmed that the enhancement of photochemical etching is wavelength selective. Only 532 n...