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...

Recent progress of wet etching of Z-cut LN, of inductively coupled plasma (ICP-) etching of X-cut LN, and of ICP-etching of proton-exchanged X-cut LN is reported to fabricate low loss ridge guides, micromechanical, and photonic crystal structures. Introduction The development of lithium niobate (LiNbO3, LN) integrated optical devices requires etching techniques for a reliable fabrication of dee...

background: the poly-allyl diglycol carbonate (padc) detector is of particular interest for development of a fast neutron dosimeter. fast neutrons interact with the constituents of the cr-39 detector and produce h, c and o recoils, as well as (n, α) reaction. these neutron- induced charged particles contribute towards the response of cr-39 detectors. material and methods: electrochemical etchin...

Wet anisotropic etching based silicon micromachining is an important technique to fabricate freestanding (e.g. cantilever) and fixed (e.g. cavity) structures on different orientation silicon wafers for various applications in microelectromechanical systems (MEMS). {111} planes are the slowest etch rate plane in all kinds of anisotropic etchants and therefore, a prolonged etching always leads to...

It is meaningful to study the surface morphology of monocrystalline material, but there are few studies on the surface roughness of quartz. So, surface roughness of Z-cut quartz etched by pure ammonium bifluoride and ammonium bifluoride mixed with isopropyl alcohol (IPA) solution was investigated for the first time in this paper. Firstly, when etching in pure ammonium bifluoride solutions, the ...

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...

objectives: the aim of this in-vitro study was to assess the thermal effect of light emitting diode (led) light curing unit on the enamel etching time. materials and methods: three treatment groups with 15 enamel specimens each were used in this study: g1: fifteen seconds of etching, g2: five seconds of etching, g3: five seconds of etching plus led light irradiation (simultaneously). the micro ...

We present the enhanced wet etching of GaN epilayer implanted with Au+ ion. Patterned GaN with 2 microm-wide sink-like strips was achieved by using 500 keV Au+ ion implantation and KOH etching. The Dependence of etching depth on etching time for the implantation at different ion fluences was investigated. The experiment showed that the damaged GaN area could be almost etched out at high ion flu...

Metal-assisted chemical etching of silicon is an electroless method that can produce porous silicon by immersing metal-modified silicon in a hydrofluoric acid solution without electrical bias. We have been studying the metal-assisted hydrofluoric acid etching of silicon using dissolved oxygen as an oxidizing agent. Three major factors control the etching reaction and the porous silicon structur...

There are basically two ways to etch silicon: dry and wet chemical etching. In micromachining, the control of the shape of the structure is accomplished by anisotropic etching through mask openings. The anisotropy of wet chemical etching is related to the crystal structure of silicon, while that of dry etching stems from the momentum of ions impinging the substrate. The latter gives us much mor...