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3 results on '"atomik kuvvet mikroskopisi"'

1. The Effect of Different Surface Treatments on the Color Stabilities of Lithium Disilicate Material

Author

Onur Doğan Dağ, Göknil Alkan Demetoğlu, and Ayşegül Kurt

Subjects
lityum disilikat, atomik kuvvet mikroskopisi, lazerler, yaşlanma, renk, lithium disilicate, atomic force microscopy, lasers, aging, color, Dentistry, RK1-715
Abstract

Background: The aim of this study is to investigate the clinical acceptability of the color change that may occur in time about full ceramic materials used for aesthetic restorations, which are bonded after different surface conditioning processes, by measuring with spectrophotometer. Methods: The lithium disilicate CAD material we used in our work was prepared with isomet in the form of 1-millimeter-thick specimens. Three random groups of 21 specimens were selected from the specimens. One of these groups was conditioned with phosphoric acid, which is recommended by the manufacturer. Er:YAG laser was applied to the second group. The third group was conditioned by Nd:YAG laser. Surface changes in the groups were evaluated by scanning electron microscope (SEM) and atomic force microscope (AFM). The specimens were bonded with the adhesive resin cement to the background material for color change measurement. The first color measurement of the bonded specimens was done by spectrophotometer. The specimens were aged at 10,000 cycles in the thermal cycle device. The second color measurement after aging was done with the same spectrophotometer. Results: After aging with thermal cycle, there was a clinically acceptable color change in all groups. The Nd:YAG laser group presented better color stability (p

Published
2023
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2. Topographic features of extracorporeal circulation circuit surface observed by atomic force microscopy; coated or non-coated?

Author

Ceviker, Kadir, Sahinalp, Sahin, and Yazkan, Rasih

Abstract

Objective: Polymer based materials used in the manufacture of extracorporeal circulation (ECC) circuit that is the main part of the heart lung machine used in cardiac surgery, poses the unavoidable inflammatory and coagulation reactions because of the contact with the tissue and biological fluids particularly the blood. The reason for these reactions may include chemical properties of the material used but the surface properties of the contact surface are also important. Atomic force microscopy (AFM) is useful method to analyze the surface morphology of a thin line and obtain information about the thickness, roughness and height asymmetries values such as the skewness and kurtosis of the line. The aim of the study is demonstrating the ECC circuits' topographic features that hypothesized as one of the main reason for side effect reactions as inflammation and coagulation. [ABSTRACT FROM AUTHOR]

Published
2016

3. Metal nanopartikül eklenmiş çok duvarlı karbon nanotüp modifiye camımsı karbon elektrotların hazırlanması ve analitik uygulamaları

Author

Gelmez, Buket, Dursun, Zekerya, Ege Üniversitesi, Fen Bilimleri Enstitüsü, and Kimya Anabilim Dalı

Subjects
atomik kuvvet mikroskopisi, voltammetry, Kimya A.B.D, atomic force microscopy, Dopamine, Carbon nanotubes, metal nano partikül, Kimya, askorbik asit, Nanotube, ürik asit, Chemistry, voltammetri, uric acid, Karbon nanotüp, Voltammetry, Nanoparticles, Nanotechnology, metal nano particles, ascorbic acid, dopamine
Abstract

Nanoteknoloji ve nanobilimdeki çalışmaların artmasıyla birlikte karbon türevleri de çalışılan malzemeler arasında önemli oranda yer bulmuştur. Karbon nanotüpler karbon türevleri arasında en çok tercih edilenlerdendir. Karbon nanotüplerin N,N-dimetil formamid (DMF) içerisinde dağıtıldıktan sonra camımsı karbon elektrot yüzeyine kaplanmasıyla, elektrotların yüzey alanları ve buna bağlı olarak katalitik etkileri artmıştır. Karbon nanotüp kaplanmış elektrotların yüzeyleri varolan katalitik etkilerinin artırılması amacıyla Pt nanopartiküller ile elektrokimyasal yolla modifiye edilmiştir. Hazırlanan elektrotlar ile askorbik asit, dopamin, ürik asit molekülerinin yükseltgenme tepkimeleri döngüsel voltammetri ile incelenmiş, karbon nanotüp elektrot ile yalın camımsı karbon elekroda göre katalitik etkinin arttığı görülmüştür. Pt modifiye karbon nanotüp elektrot ile pik akımlarında görülen artış ve elde edilen iyi ayrılmış yükseltgenme pikleri bu analitlerin yükseltgenmesine karşı en iyi katalitik etkinin Pt modifiye karbon nanotüp elektrot ile elde edildiğini göstermiştir. Elektrot yüzeyleri atomik kuvvet mikroskopu ve taramalı elektron mikroskopu ile karakterize edilmiştir. AA, DA, UA moleküllerinin tek tek ve birarada bulunduğu koşullardaki davranışları diferansiyel puls voltammetri ile çalışılmıştır. Belirtme sınırları tek başlarına bulunduğu koşullarda AA, DA, UA sırasıyla 1.9x10-5M, 2.78x10-8 M, 3.2x10-8M olarak bulunmuştur. Bu analitlerinin ikisinin derişiminin sabit tutulup, diğer üçüncünün derişiminin incelendiği koşullarda ise belirtme sınırları askorbik asit , dopamin ve ürik asit için sırasıyla 2x10-5 M, 4.83x10-8 M, 3.5x10-7 M olarak hesaplanmıştır.Anahtar Kelimeler: karbon nanotüp, metal nano partikül, askorbik asit, dopamine, ürik asit, voltammetri, atomik kuvvet mikroskopisi Carbon based materials were used in many research with increasing interests on nanoscience and nanotechnology. Carbon nanotubes were mostly preferred in all carbon based material.The electrode surface area and the catalytic activities were increased due to casting of multiwalled carbon nanotubes, was dispersed in N,N- dimetil formamide (DMF), on bare glassy carbon electrode. The surface was modified with Pt nanoparticules by electrochemically, to obtain higher catalytic effect than MWCNT/GCE. Electrooxidation reactions of AA, DA, UA were studied by cyclic voltammetry with all prepared electrodes. It was observed that increasing catalytic activity for modified electrodes comparing bare glassy carbon electrode. The enhanced peak current and well-defined peak seperations shows that best catalytic activity was obtained using Pt nanoparticules modified MWCNT/GCE. The surface of electrodes was characterizated by atomic force microscopy and scanning electron microscopy. Individual and simultaneous determination of ascorbic acid, dopamine and uric acid was studied by differantial pulse voltammetry. The detection limits were calculated for individually , ascorbic acid, dopamine, uric acid 1.9x10-5M, 2.78x10-8M, 3.2x10-8M, respectively. In simultaneously determination LODs were calculated for AA, DA, UA, 2x10-5 M, 4.83x10-8 M, 3.5x10-7 M, respectively.Keywords: carbon nanotubes, metal nano particles, ascorbic acid, dopamine, uric acid, voltammetry, atomic force microscopy 146

Published
2009

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