– We combine ab initio and Monte Carlo simulations in multiscale modelling of anisotropic wet chemical etching of silicon. The anisotropy of the macroscopic etching patterns observed in the experiments is explained by two mechanisms at an atomistic scale: the weakening of backbonds following OH termination of surface sites and the existence of significant interaction between the surface-termina...

The aim of the present work was to analyze the ultrastructure and mineral composition of the surface of the enamel on a molar with MIH, with and without acid etching. A permanent tooth without clinical MIH lesions (control) and a tooth with clinical diagnosis of mild and moderate MIH, with indication for extraction, were processed with and without acid etching (H3PO4 37%, 20") for observation w...

This paper presents processes for glass micromachining, including sandblast, wet etching, reactive ion etching (RIE), and glass reflow techniques. The advantages as well as disadvantages of each method are presented and discussed in light of the experiments. Sandblast and wet etching techniques are simple processes but face difficulties in small and high-aspect-ratio structures. A sandblasted 2...

CR-39 Solid State Nuclear Track Detecting foils (SSNTD), along with 1 mm thick polyethylene radiator, sealed in triple laminated pouches, are used for country wide Fast Neutron Personnel Monitoring in India. With the present system of processing by elevated temperature electrochemical etching (ETECE) and evaluation using automatic image analysis, only 16 foils are processed at a time and it is ...

Microfluidic and optical sensing platforms are commonly fabricated in glass and fused silica (quartz) because of their optical transparency and chemical inertness. Hydrofluoric acid (HF) solutions are the etching media of choice for deep etching into silicon dioxide substrates, but processing schemes become complicated and expensive for etching times greater than 1 hour due to the aggressivenes...

The purpose of this study was to evaluate the antibacterial activity of a modified self-etching primer incorporating chitosan and whether this modification affected the bond strength to radicular dentin. A modified self-etching primer was prepared by adding chitosan solutions at 0.03%, 0.06%, 0.12% and 0.25% (W/W) to RealSeal selfe-tching primer. RealSeal primer without chitosan was used as the...

in this experimental work, by using the method of plasma-chemical etching, we have dealtwith the causes of the creation of a distorted layer on the surface of silicon wafers during mechanicalmachining processes, in addition, the elucidation of connections between the structure of this layer andcharacteristic parameters of the mechanical strength of these wafers have been studied. experimentalre...

path of microleakage between the enamel and adhesive potentially allows microbial ingress that may consequently cause enamel decalcification. the aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques.the specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1), laser etching with er:yag at...

introduction: the aim of this study was to compare the micro-shear bond strength of composite resin on superficial and deep dentin after conditioning with phosphoric acid and erbium-doped yttrium aluminum garnet (er:yag) laser. methods: thirty human molars were selected, roots were removed and crowns were bisected to provide a total of 60 half-crowns. specimens were ground to expose superficial...

When etching high-aspect-ratio silicon features using deep reactive ion etching DRIE , researchers find that there is a maximum achievable aspect ratio, which we define as the critical aspect ratio, of an etched silicon trench using a DRIE process. At this critical aspect ratio, the apparent etch rate defined as the total depth etched divided by the total elapsed time no longer monotonically de...