Atom force microscopy as a tool for the evaluation of the quality of contact lenses surface

2016 ◽  
Vol 4 ◽  
pp. 455-468
Author(s):  
Agnieszka Tomaszewska
Keyword(s):  
Contact Lenses ◽  
Force Microscopy ◽  
Atom Force Microscopy ◽  
Quality Of Contact

The visualization and assessment of the anterior surface of the cornea using video keratotopography

The Eye ◽  
2020 ◽  
Vol 22 (130) ◽  
pp. 36-43
Author(s):  
Gulnara Andrienko
Keyword(s):  
Contact Lenses ◽  
Corneal Topography ◽  
Topographic Maps ◽  
Specific Situation ◽  
Main Method ◽  
Pathological Conditions ◽  
Quality Of Vision ◽  
Corneal Shape ◽  
Color Map

Corneal topography is the main method for assessing the regularity of the surface of the cornea. Corneal irregularity leads to a deterioration in its refractive properties and a decrease in the quality of vision. Learning the basics of corneal topography will help determine the choice of a color map for a specific situation, as well as understand and analyze the data associated with these maps. This article describes the main types of topographic maps, various patterns of corneal shape in normal and pathological conditions and how to use the data obtained to design and fit contact lenses. Despite the fact that images may vary depending on topographers used, the information presented in this article is universal.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

Characterization of the porous nature of a phthalocyanine derivative with axial ligation designed to prevent aggregation

2010 ◽  
Vol 14 (05) ◽  
pp. 389-396
Author(s):  
Carl A. Barker ◽  
Alan Massey ◽  
Aidan Rhodes ◽  
Martin R. Bryce ◽  
Ritu Kataky
Keyword(s):  
Force Microscopy ◽  
Selective Transport ◽  
Electrode Surfaces ◽  
Axial Ligation ◽  
Nanoporous Films ◽  
Atom Force Microscopy ◽  
Solvent Cast ◽  
Complementary Techniques

Judiciously designed phthalocyanines (Pcs), such as silicon-Pc bis(3,5-diphenyl)benzoate (1c), with axial substituents which prevent aggregation, can self-assemble to form ordered nanoporous films on electrode surfaces. In this paper, complementary techniques such as Scanning Kelvin Nanoprobe (SKN) microscopy, Atom Force Microscopy (AFM) and electrochemical measurements are used to demonstrate that films formed by silicon-Pc bis(3,5-diphenyl)benzoate allow size- and charge- selective transport of probe molecules through well-defined intermolecular cavities. In contrast, the analogs silicon-Pc bis(4-tert-butylbenzoate) (1a) and silicon-Pc bis(3-thienyl)acetate (1b) have different film morphologies when solvent-cast in the same manner and block the electrode surface. The role of the different axial substituents in orienting the molecules on the substrate is discussed.

Mechanical Interlocking on Leadframe Surface for Bondability of Au Wedge Bond

2016 ◽  
Vol 857 ◽  
pp. 79-82
Author(s):  
Roslina Ismail ◽  
Fuaida Harun ◽  
Azman Jalar ◽  
Shahrum Abdullah
Keyword(s):  
Optical Microscope ◽  
Bonding Process ◽  
Mechanical Interlocking ◽  
Average Roughness ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Morphologies ◽  
Scanning Electron ◽  
Effect Of Surface

This work is a contribution towards the understanding of wire bond integrity and reliability in relation to their microstructural and mechanical properties in semiconductor packaging.The effect of surface roughness and hardness of leadframe on the bondability of Au wedge bond still requires detail analysis. Two type of leadframes namely leadframe A and leadframe B were chosen and scanning electron microscope (SEM) and optical microscope were used to inspect the surface morphology of leadframes and the quality of created Au wedge bond after wire bonding process. It was found that there were significant differences in the surface morphologies between these two leadframes. The atomic force microscopy (AFM) which was utilized to measure the average roughness, Ra of lead finger confirms that leadframe A has the highest Ra with value of 166.46 nm compared to that of leadframe B with value of 85.89 nm. While hardness value of different lead finger from the selected leadframe A and B obtained using Vicker microhardness tester are 180.9 VH and 154.2VH respectively.

Effect of Via Etch Profile and Barrier Metal on Electromigration Performance of W-Filled Via Structure in TiN/AlCu/TiN Metallization

1995 ◽  
Vol 391 ◽  
Author(s):  
Larry M. Ting ◽  
G. Dixit ◽  
M. Jain ◽  
K. A. Littau ◽  
H. Tran ◽  
...  
Keyword(s):  
Critical Factor ◽  
Process Variations ◽  
Precise Control ◽  
Bottom Level ◽  
Via Hole ◽  
Barrier Metal ◽  
Etch Profile ◽  
Quality Of Contact

AbstractIn this study, we have evaluated electromigration performance of W-plug vias, fabricated with process variations in via hole etching as well as in via barrier deposition, on a TiN(barrier)/AlCu/TiN metallization system. We found that via etch profile scheme as well as deposition conformity for via barrier can significantly affect W-plug via lifetimes. The results indicate that the quality of contact with AlCu layer of bottom level metal is a critical factor in determining via lifetime. Precise control of via etching or by use of conformal via barrier to ensure a good barrier between W-plug and the AlCu of bottom level metal is essential for achieving reliable via structures.

scholarly journals Osteoblast-Like Cell Behavior on Porous Scaffolds Based on Poly(styrene) Fibers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Andrada Serafim ◽  
Romain Mallet ◽  
Florence Pascaretti-Grizon ◽  
Izabela-Cristina Stancu ◽  
Daniel Chappard
Keyword(s):  
Interference Microscopy ◽  
Porous Scaffolds ◽  
Allogenic Bone ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dry Spinning ◽  
Bone Trabeculae ◽  
Large Bone

Scaffolds of nonresorbable biomaterials can represent an interesting alternative for replacing large bone defects in some particular clinical cases with massive bone loss. Poly(styrene) microfibers were prepared by a dry spinning method. They were partially melted to provide 3D porous scaffolds. The quality of the material was assessed by Raman spectroscopy. Surface roughness was determined by atomic force microscopy and vertical interference microscopy. Saos-2 osteoblast-like cells were seeded on the surface of the fibers and left to proliferate. Cell morphology, evaluated by scanning electron microscopy, revealed that they can spread and elongate on the rough microfiber surface. Porous 3D scaffolds made of nonresorbable poly(styrene) fibers are cytocompatible biomaterials mimicking allogenic bone trabeculae and allowing the growth and development of osteoblast-like cellsin vitro.

scholarly journals STUDY OF THE OPTICAL POWER OF NANOPHOTONIC SOFT CONTACT LENSES BASED ON POLY (2- HYDROXYETHYL METHACRYLATE) AND FULLERENE

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Aleksandra Debeljković Mitrović ◽  
Dragomir Stamenković ◽  
Manuel Conte ◽  
Božica Bojović ◽  
Spomenko Mihajlović
Keyword(s):  
Contact Lens ◽  
Contact Lenses ◽  
Measurement Techniques ◽  
Optical Power ◽  
Soft Contact ◽  
Standard Material ◽  
Soft Contact Lenses ◽  
Soft Contact Lens ◽  
Power Cylinder

In this paper results of comparative study of the optical power of soft contact lenses (SCL) made of standard material for SCL and nanophotonic materials with different measurement techniques used for the final contact lens controllers are presented. Three types of nanophotonic soft contact lenses were made of standard polymacon material (Soleko SP38TM) incorporated with fullerene C60, fullerol C60(OH)24 and fullerene metformin hydroxylate C60(OH)12(OC4N5H10)12. For the purposes of material characterization for potential application as soft contact lenses, the optical properties of the soft contact lenses were measured by Rotlex and Nidek device. With Rotlex device the following optical results were obtained: optical power and map of defects, while with the Nidek device: optical power, cylinder power and cylinder axis. The obtained values of optical power and map of defects showed that the optical power of synthesized nanophotonic soft contact lens is same to the nominal value, while this was not the case for the standard soft contact lens. Also, the quality of the nanophotonic soft contact lens is better than the standard one. Hence, it is possible to synthesize new nanophotonic soft contact lenses of desired optical characteristics, implying possibilities for their application in this field.

scholarly journals Аналіз методів оцінки та впливу полірованості композитних матеріалів на функціональний прогноз реставрацій

2018 ◽  
Author(s):  
S. B. Kostenko ◽  
I. Y. Hangur ◽  
I. V. Sorokopud ◽  
M. Y. Goncharuk-Khomyn ◽  
G. N. Nakashidze
Keyword(s):  
Numerical Data ◽  
Color Stability ◽  
Stability Parameters ◽  
Force Microscopy ◽  
Composite Restorations ◽  
Usphs Criteria ◽  
Bacterial Plaque ◽  
Microsoft Office

Summary. Among the proposed USPHS criteria approved by FDI, the level of gloss and polishing of restorations plays a key role in preventing not only such complications  as disocorporations or changes in their texture in the future, but also preventing secondary caries and sealing disintegration, since areas with high roughness play the role of retention points for the accumulation of bacterial plaque and the further progression of the above-described complications.The aim of the study – to analyze the methods for assessing the quality of polishing composite restorations and to determine the role of influence roughness factor of their surface on the prediction of their functioning and change of color stability parameters, formation of biofilm and shine.Materials and Methods. Search of publications related to the topic of this analysis was conducted by the Google Scholar search engine by the keywords "roughness", "polishing", "composite restorations" and their analogues in English. The depth of search, taking into account the age of key articles, determined by the level of their citation in later periodicals, did not exceed 15 years. In order to organize the received data, Microsoft Excel 2016 (Microsoft Office) table editor was used to group  pre-selected articles based on the results of the provided content analysis.Results and Discussion. In the course of the analysis, it was established that the basic laboratory methods for assessing the roughness of the restoration surface, as an indicator of the quality of polishing, are atomic force microscopy, scanning electron microscopy and profilometry. Most often, in order to verify the aforementioned parameter in the analyzed studies, the Ra value of mean arithmetic deviation of the profile was used, on the basis of which analysis it was possible to determine the dependence of the possibilities for achieving the corresponding level of restoration polishing on the structure of the composite material used, the system and phases of polishing, and the tribological nature of the interaction of the polishing system and the surface of the restoration.Conclusions. The results of the analysis show that the data obtained in the course of previous clinical and laboratory studies dedicated to the effect of polishing on various restoration parameters are debatable and a more specific systematization is required, with the selection of the investigated aspects of brightness, roughness, color stability and functional prediction changes due to the polishing method in separate independent subjects for research, with further phased combination of them after obtaining unambiguous numerical data, subjected to appropriate objective interpretation.

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