Search for dissertations about: "lens"

Showing result 16 - 20 of 482 swedish dissertations containing the word lens.

  2. 16. Photonic THz Generation and Quasioptical Integration for Imaging Applications

    Author : Biddut Kumar Banik; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nondestructive evaluation; semiconductor device modelling; uni-travelling-carrier photodiodes; millimetre wave and submillimetre wave generation; III-V semiconductors; photomixers; terahertz sources.; catadioptric lens; microwave imaging; dielectric loaded antennas; terahertz imaging; lens antennas; millimetre wave and submillimetre wave imaging;

    Abstract : This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequencyrange. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. READ MORE

  4. 17. Ultraviolet radiation cataract

    Author : Konstantin Galichanin; Karolinska Institutet; Karolinska Institutet; []
    Keywords : lens;

    Abstract : Cataract is the leading cause of blindness in the world. Epidemiological and experimental evidence supports a link between mid-range ultraviolet radiation (UVR-B) exposure and the development of cataract. READ MORE

  5. 18. Damage mechanisms for near-infrared radiation induced cataract

    Author : Zhaohua Yu; Per Söderberg; Konstantin Galichanin; Masami Kojima; Uppsala universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; infrared radiation; photochemical; thermal; forward light scattering; lens; cataract; temperature; Arrhenius equation; heat diffusion;

    Abstract : Purpose: 1) To estimate the threshold dose and the time evolution for cataract induction by near infrared radiation (IRR) in seconds exposure time domain; 2) to determine the ocular temperature development during the threshold exposure; 3) to investigate if near IRR induces cumulative lens damage considering irradiance exposure time reciprocity; 4) to experimentally estimate the temperature in the lens indirectly from the measurement of temperature-induced light scattering increase.Methods: Before exposure, 6-weeks-old albino rats were anesthetized and the pupils of both eyes were dilated. READ MORE

  6. 19. MULTIFOCAL SPHERICAL FISH LENSES

    Author : Yakir Gagnon; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Multifocal Lens; Adaptation; Dispersion; Spherical lens; Model; Fish; Ray-trace; Longitudinal Chromatic Aberration; Longitudinal Spherical Aberration; Modulation Transfer Function; Point Spread Function; Refractive Index Gradient;

    Abstract : Vision is an important source of information for many animals. The lens plays a central role in the visual pathway and hence the ecology of these animals. Fish have spherically shaped crystalline lenses that contain a gradient of refractive index. Like all refracting elements, lens performance depends on the wavelength of the refracted light. READ MORE

  7. 20. Supernovae under the gravitational lens

    Author : Christofer Gunnarsson; Joakim Edsjö; Tereasa Brainerd; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Cosmology; Cosmology; Kosmologi;

    Abstract : With general relativity as its foundation, the Standard Model of Cosmology has been developed, a model in which all matter is homogeneously and isotropically distributed throughout the Universe. We know for sure that this is not true since inhomogeneous structures such as galaxies, planets and synthesizers, are known to exist on small cosmological scales. READ MORE