نتایج جستجو برای: hard lens
تعداد نتایج: 197097 فیلتر نتایج به سال:
purpose: to compare visual outcomes and surgical complications of three phakic intraocular lenses (piols); artisan, artiflex and the implantable collamer lens (icl) for correction of moderate to high myopia. methods: in this historical cohort study, 112 myopic eyes that were operated between 2005 and 2010 and implanted with one of these three piols were evaluated (artisan 40 eyes, artiflex 36 e...
background: silicon hydrogel bandage contact lenses are used to enhance epithelial healing, control surface-generated pain, and prevent epithelial erosions after refractive surgery. considering the importance of faster reepithelialization in preventing complications of photorefractive keratectomy (prk) and the fact that the features and specifications of these commercially-available lenses are ...
The magnifications of the images in a strong gravitational lens system are sensitive to small mass clumps in the lens potential; this effect has been used to infer the amount of substructure in galaxy dark matter halos. I study the theory of substructure lensing to identify important general features, and to compute analytic cross sections that will facilitate further theoretical studies. I sho...
Introduction: Eye lens is a very sensitive organ to the x-ray radiation and cataract could be formed as a result of eye exposure. Computed tomography (CT) is one of the main exposure sources in clinical situations and brain imaging delivers high amount of exposure to the eye lens. To reduce eye lens dose, efficient dose reduction methods have to be developed and implemented. In this paper, the ...
Lens coupled tunable Young’s double pinhole system for hard X-ray spatial coherence characterization
آرایه فازی به منظور هدایت بیم در راستایی خاص نیازمند شبکه تغذیه ویژه ای می باشد. رتمن لنز به عنوان یکی از این ساختارهای تغذیه با قابلیت تحریک چند بیم در زوایای متفاوت در یک زمان، استفاده گسترده ای پیدا کرده است. در این پژوهش مهم ترین عوامل موثر بر پهنای باند این شبکه در ساختار مایکرواستریپ، که شبکه تطبیق امپدانس، رفتار انتشاری موج در بخش صفحات موازی و خطای فاز خطوط انتقال می باشند، بررسی شده و ...
OBJECTIVES The aim of this study was to measure tear film surface quality (TFSQ) using dynamic high-speed videokeratoscopy during short-term (8 hrs) use of rigid and soft contact lenses. METHODS A group of 14 subjects wore 3 different types of contact lenses on 3 different nonconsecutive days (order randomized) in 1 eye only. The subjects were screened to exclude those with dry eye. The lense...
A method was proposed for analyzing the optical glass lens centering process, and experiments on biplane quartz lenses were performed to determine material removal rate (MRR) hard, brittle material. This study used acoustic emission–sensing technology monitor MRR reconstruct original shape of lens. The evaluated, an error 17.87% obtained. Taguchi experiment combined with signal analysis optimiz...
Objective- Assessment of the lens anterior – posterior (AP) diameter as compared with the eye globe by ultrasonography in rabbit. Design- Descriptive study. Animals- 120 male and female rabbits, two months to four years old, and weighting between 300 to 1500gr. Procedures- 2D ultrasonography of the eyes was performed and AP diameter of the eyes and lens were measured using Sonosite Tit...
Horn antennas can result in good impedance matching between the waveguide and free space due to the gradual increase in the aperture size. In this paper, a novel plasmonic sectoral horn nanoantenna based on using lens in the aperture is proposed. It is investigated that in addition to improvement of the directivity, the reflection coefficient is also reduced using the proper lens structure. The...
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