نتایج جستجو برای: optical density

تعداد نتایج: 658578  

Journal: :Acta ophthalmologica 2015
Stanley Darma Pauline H B Kok Thomas J T P van den Berg Michael D Abràmoff Dirk J Faber Caroline A Hulsman Frank Zantvoord Maarten P Mourits Reinier O Schlingemann Frank D Verbraak

PURPOSE To assess the effect of media opacities on thickness measurements of the peripapillary retinal nerve fibre layer (pRNFL) and macular inner retinal layer (mIRL) performed with spectral-domain optical coherence tomography (SD-OCT) using a set of filters with known optical density. METHODS Spectral-domain optical coherence tomography volume scans of the optic disc and the macular area we...

Journal: :Current eye research 2006
John M Nolan Jim Stack John Mellerio Margery Godhinio Orla O'Donovan Kumari Neelam Stephen Beatty

PURPOSE This study was undertaken to assess serial month-to-month consistency of macular pigment (MP) optical density and serum concentrations of lutein (L) and zeaxanthin (Z). Four healthy subjects aged between 23 and 51 years volunteered to participate in this study. METHODS MP optical density (measured psychophysically using heterochromatic flicker photometry [HFP]), and serum concentratio...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1387

چکیده ندارد.

2006
Julio Cezar de Melo CASTILHO Wilton Mitsunari TAKESHITA Luis Roque de Araújo dos SANTOS Luiz Cesar de MORAES Edmundo MEDICI Mari Eli Leonelli de MORAES

The purpose of this article was to compare the mean value of optical density of four porcelains commonly used for fabrication of inlay/onlay prostheses using direct digital radiograph. The sample consisted of 20 2-mm thick porcelain specimens (measured by digital pachymeter): Empress (Ivoclair), Simbios (Degussa), Vita Omega 900 and Vitadur Alpha (Vita Zahnfabrik). The values of optical density...

Signal optimization is affected during radio links between a transmitter and a receiver located in adjacent material media with differing optical densities. The optimization is carried out via the automated control theory method. The radio signal obtained after the optimization is coordinated with the two media's electrical characteristics simultaneously; and this enables low power and small an...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی 1386

چکیده ندارد.

ژورنال: مجله دندانپزشکی 2002
طلایی پور, احمدرضا, باشی زاده فخار, حوریه , دباغی, آرش ,

Nowadays, bone mass estimation, through imaging methods, is widely used in metabolic diseases diagnosis and treatment. One of these methods is called "optical densitometry" which estimates bone density by measuring the intensity of the transmitted light on different parts of a radiographic image. Digital radiography systems act similarly by determining grey levels of the image. The aim of this ...

Journal: :مهندسی متالورژی و مواد 0
نگار عباسی اول خدیجه فرجام حسین آقاجانی

in this study, the effect of grain size on nitrogen diffusion into ck45 has been investigated. in order to obtain different grain sizes, samples were annealed and normalized at various temperatures and durations.the grain size was determined with clemex vision software. then, the specimens were exposed to dc plasma nitriding treatment and again analyzed by optical microscope ,scanning electron ...

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