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Evaluation of the Level of Transmission of Solar Radiation by Eyeglasses (Spectacles) and its Effects on the Human Eye
摘要： Global atmospheric changes such as depletion of Ozone in the stratosphere and global warming contribute to the average increase of ultraviolet radiation on earth. Protective eyeglasses are normally recommended to safeguard the eyes from the harmful effects of solar radiation. In this paper, twenty (20) pairs of eyeglasses were selected based on systematic random sampling to determine the amount of optical radiation transmission and level of attenuation by eyeglasses, in the wavelength range of 200nm to 900nm using 6405 UV/VIS spectrophotometer. All the eyeglasses were found to transmit a substantial amount of ultraviolet radiation. The transmission of visible light depends on the lens colours. It was discovered that the eyeglasses do not provide complete protection from UV radiation. This shows that the glasses can still pose great danger to human eyes.
关键词： Spectrophotometer,Eyeglasses,Human eye,Percentage transmittance (%T),Optical radiation,Global warming,Depletion of Ozone,Solar radiation,Attenuation
更新于2025-09-04 15:30:14
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Relación de la Transmitancia Atmosférica con la Heliofanía y la Diferencia de Temperaturas Extremas Diarias en la Zona Ecuatorial Andina
摘要： In this work, values of atmospheric transmittance coefficients using heliophany (sunshine hours) and the difference between maximum and minimum temperatures are proposed for a city located in the Andean Ecuadorian zone. First, the extraterrestrial radiation was calculated to study the reliability of the models. Later, statistical techniques were applied to meteorological data measured since June 2007 for a period of almost five years. These data were used to calculate the empirical lineal coefficients between different variables, using three models: one using heliophany and two using the difference between temperatures. The results showed that there is a more consistence relation between solar radiation and sunshine hours. In addition, it was established that it is not adequate to generalize the results to other locations even if they have similar weather characteristics.
关键词： solar radiation,atmospheric transmittance,Andean Ecuador,extraterrestrial solar radiation
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Revisiting field layout designs for large STE tower plants
摘要： Solar Thermal Electricity (STE/CSP) Tower Plants suffer a reduction on the solar field efficiency when their size increases. As plant-size is an important driver for the reduction of generation costs of STE plants - due to the relative impact of the power block and the O&M costs - plant-size could be a big disadvantage for tower plants. To cope with this issue a new rationale is proposed for designing the new generation of large tower plants. This paper demonstrates the performance benefits of the multitower approach, with single storage and power block and with northern fields versus large surrounded type; all at different latitudes and different atmospheric transmittance conditions. Field sizes of 50 MW equivalent - for plants with medium storage - appears to be a kind of standard for locations with relatively clear atmosphere while, in hazy locations, smaller sizes around 30 MW should be preferred. Besides the efficiency advantages, standardizing the designs and making them modular could also contribute to reduction of soft costs for this technology. As the improvement achieved in the solar field seems to offset the investment of an additional but smaller tower and receiver, the multitower approach might lead to a certain cost reduction of STE tower plants.
关键词： field efficiency,CSP,multitower approach,STE,northern fields,Tower Plants,Solar Thermal Electricity,atmospheric transmittance
更新于2025-09-04 15:30:14
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Modification of GaN thin film on sapphire substrate optical properties under weak magnetic fields
摘要： We present a study of the modifications to the optical transmittance of GaN thin film on sapphire substrate due to weak magnetic field (WMF) treatment. Measurements were performed in the 320-1100 nm wavelength range at 300 K, evidencing a change in transmission spectra for wavelengths above 700-800 nm after the WMF treatment. We use a model with three layers to simulate transmittance spectra. We have found that changes of the optical thickness induced by WMF are not sufficient to explain discrepancies between experimental and simulated spectra. To obtain a complete agreement it is necessary to consider a change in the refractive index of GaN and/or in the reflection coefficients for the interface air-GaN. We interpret such WMF-related effects as due to the diffusion of point defects after dissolution of metastable complexes from inner boundaries to surface of the structure. These defects modify optical properties of the GaN film.
关键词： reflectance,transmittance,weak magnetic field,gallium nitride
更新于2025-09-04 15:30:14
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Numerical Investigation for Scale-Up of an Electron Cyclotron Resonance Plasma for Fluorine-Doped Tin Oxide Thin Film Production
摘要： A low-temperature process is required to deposit ?uorine doped tin oxide (FTO) as a transparent conductive oxide on polyethylene terephthalate (PET) substrate, as the latter is polymeric and has a low melting point. An electron cyclotron resonance (ECR) plasma system is the best way to deposit metal oxide with high transparency and electrical conductivity at temperatures below 100 (cid:2)C. Characteristics of an ECR plasma include its high ionization energy and electron density; however, its use is limited in large-scale deposition. In order to overcome this limitation, a large-scale ECR plasma system with a dual microwave generator was designed by numerical investigation of a laboratory-scale ECR plasma system. FTO ?lms prepared in the laboratory-scale and large-scale systems were compared. The change in electrical resistivity and optical transmittance with deposition pressure in the large-scale ECR plasma system with dual linear microwave generator is similar to that observed in the laboratory-scale ECR plasma system. The velocity distribution of active species near the substrate in the large-scale ECR plasma system showed a very similar pattern to that in the laboratory-scale ECR plasma system over a range of 1.5 × 10?2 to 0.8 × 10?2 m/s. The electrical resistivity and optical transmittance of FTO ?lms deposited by a large-scale ECR plasma system using a dual microwave generator had respective values of 4.3 × 10?3 ～ 9.18 × 10?3 (cid:2) · cm and 86.5～88.2%.
关键词： Dual Microwave,ECR Plasma,Electrical Resistivity,Optical Transmittance,Fluorine-Doped Tin Oxide
更新于2025-09-04 15:30:14
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Reversible Photodoping of TiO <sub/>2</sub> Nanoparticles for Photochromic Applications
摘要： Observations on the strong photochromic effect of crystalline TiO2 quantum dots (mean size ≈ 4 nm) are presented. The synthesized quantum dots consist of irregularly shaped anatase TiO2 nanoparticles (NPs) and are dispersed in butanol (8% by mass). Obtained NPs exhibit a dramatic photoresponse to UV light, enabling effective transmittance modulation in a broad wavelength range extending from the visible to near-infrared region, and even the thermal black body radiation regime beyond 10 μm. The exceptional photoresponse is attributed to hole-scavenging by butanol, TiO2 self-reduction, injection of electrons to the conduction band, and consequent localized surface plasmon resonances in NPs. The observed optical effect is reversible, and the initial high transmittance state can be restored simply by exposing the NPs to air. The applied NP synthesis route is economic and can be easily scaled for applications such as smart window technologies.
关键词： UV light,TiO2 nanoparticles,localized surface plasmon resonances,transmittance modulation,photochromic
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Leaf Water Status from Lab Estimates of VIS-NIR Reflectance and Transmittance
摘要： Remotely sensing the water status of plant canopies remains a long term goal of remote sensing research. Established approaches involve measurements in the thermal infrared and the 900-2000nm reflective infrared. Less popular UV-visible-NIR techniques presumably deserve research attention, because photochemical changes linked to plant water status manifest spectral light scattering and absorption changes. Here we estimated the visible and NIR light reflected from the leaf interior and the leaf transmittance of corn (Zea mays L.) leaves having a range of relative water contents. Our results highlight the importance of both scattering effects and effects due to absorption by leaf pigments.
关键词： leaf reflectance,leaf relative water content,RWC,leaf transmittance
更新于2025-09-04 15:30:14
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Highly Transparent Conducting Indium Tin Oxide Thin Films Prepared by Radio Frequency Magnetron Sputtering and Thermal Annealing
摘要： High-quality ITO (indium tin oxide) films were grown by radio frequency (RF) magnetron sputtering and post thermal annealing. Both the thermal annealing temperature and the atmosphere significantly influenced the optical and electrical properties of ITO films. The as-grown 110-nm-thick ITO film showed an optical transmittance of 34.2% at a wavelength of 550 nm and electrical resistivity of 9.2 × 10?4 Ωcm. Notably, the ITO films annealed at 850 °C for 1 min in nitrogen ambient led to a significantly improved optical transmittance (97.3%) and the low electrical resistivity of 1.3 × 10?4 Ωcm, while those annealed in air or oxygen ambient produced poorer electrical properties despite their good optical transmittance owing to the presence of oxygen. The high quality of the ITO film annealed in nitrogen could be attributed to the combined effects of effective suppression of oxygen incorporation into films (thus maintaining oxygen vacancies in the ITO film), enhanced Sn doping, and improved the crystallinity with larger grain size.
关键词： ITO,RF-Magnetron Sputtering,Optical Transmittance,Rapid Thermal Annealing
更新于2025-09-04 15:30:14
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Synthesis, Growth, Optical and Dielectric Characterization of 8-Hydroxyquinolinium Hydrogen Fumarate Single Crystal
摘要： An organic nonlinear optical single crystal, 8-hydroxyquinolinium hydrogen fumarate (8HQF) was grown from mixed solvent of ethanol and water using slow evaporation solution growth technique. The single crystal XRD studies confirmed that the grown crystal belongs to the triclinic crystal system with the centrosymmettric space group P ī. FT-IR spectral analysis confirms the various functional groups present in the compound. The optical absorption studies shows that the crystal is transparent with a lower cut-off wavelength of 439 nm and the optical energy band gap Eg is found to be 2.66 eV. The variation of dielectric properties of the grown crystal with respect to the frequency has been investigated at different temperatures.
关键词： Vibrational analysis,Solution growth,Optical transmittance
更新于2025-09-04 15:30:14
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Temperature Effect on Optical and Electrical Properties of ZnO Films
摘要： Zinc oxide thin films were deposited on a glass substrate by Radio frequency magnetron sputtering. The effect of substrate temperature on the microstructure, optical and electrical properties was investigated. Crystal structure and surface morphology of the films were examined by X-ray diffraction and atomic force microscopy. XRD patterns and AFM images show that the crystallinity and grain size are increasing with the increase of substrate temperature. Electrical properties of the films were evaluated by Hall effect measurements. Experimental results indicate a decrease of film resistivity with the increase of substrate temperature. Zinc oxide films exhibit high transmittance of 84 % in the visible wavelength range 400-800 nm and is independent on the substrate temperature. Present work shows that the enhancement of the ZnO film performance with high transparency and low resistivity can be achieved by increasing the substrate temperature.
关键词： Resistivity,Zinc oxide film,Transmittance,Substrate temperature
更新于2025-09-04 15:30:14