The knife-edge method is a commonly used technique to characterize the optical profiles of laser beams or focused spots. In this paper, we present a micro knife-edge scanner fabricated in a silicon-on-insulator substrate using the micro-electromechanical-system technology. A photo detector can be fabricated in the device to allow further integration with on-chip signal conditioning circuitry. A...

introduction : the aim of this study was to examine and compare the apical sealing ability of ah26, ah plus and ah plus jet using a fluid filtration model. materials and methods : 70 single-rooted teeth were dissected from the cement-enamel junction. canals were prepared with protaper rotary system and manual k files and irrigated with 5.25% naocl and 17% edta. ten teeth were assigned as contro...

In complex cases of enamel fluorosis or enamel dys-mineralization, combined bleaching and micro-abrasion therapies may be advocated. The aim of the present study was to investigate the effect of combined in-office bleaching and micro-abrasion on the bond strength of two dental adhesives bonded to surface enamel. The interfacial micro-morphology of the involved surfaces was also studied by using...

introduction: the aim of this study was to evaluate the composite surface treated by different powers of erbium-doped yttrium aluminum garnet (er:yag) laser in comparison with bur preparation via scanning electron microscope. methods: fourteen composite resin blocks with 15× 10 × 10 mm dimensions were used in this study. the samples were divided to seven groups as follow: group 1 (power: 1 w, e...

. this paper presents the results of an experimental investigation on shear strength enhancement of reinforced concrete deep beams externally reinforced with fiber reinforced polymer (frp) composites. a total of six deep beam specimens of two different classes, as-built (unstrengthened) and retrofitted were tested in the experimental evaluation program. two composite systems namely carbon/epoxy...

We present in this paper the findings of a study on the role of macroadaptation in conversational intelligent tutoring. Macro-adaptivity refers to a system’s capability to select appropriate instructional tasks for the learner to work on. Micro-adaptivity refers to a system’s capability to adapt its scaffolding while the learner is working on a particular task. We compared an intelligent tutori...

background: lemon verbena (lippia citriodora h.b.k.) is an aromatic and medicinal plant of family verbenaceae, which cultivated in north region of iran. objective: evaluation of phytochemical characters in lippia citriodora h.b.k. plantlets affected by propagation methods (micro-propagation and stem cutting) cultivated in different soil type (peat moss and mixture soil). methods: this study was...

objective: tooth surface undergoes continuous remineralization and demineralization. the aim of this study was to compare the effect of caseinphosphopeptide-amorphous calcium phosphate (cpp-acp) paste and fluoride gel on the microhardness of demineralized enamel lesions.   methods: frothy eight specimens of premolar teeth were chosen and randomly divided to 4 groups of 12. after the initial mea...

MEMS is the acronym for Micro Electro Mechanical Systems. Micromachining has potential applications for large area image sensors and displays, but conventional MEMS technology, based on crystalline silicon wafers cannot be used. Instead, large area devices use deposited films on glass substrates. This presents many challenges for MEMS, both as regards materials for micro-machined structures and...

Combining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages of each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling of single particles. On the other hand, acoustic trapping with wavelengths of about 1 mm allows the simultaneous trapping of many, ...