GaAs/Ge solar cell AC parameters under illumination

The ac parameters of GaAs/Ge solar cell were measured under illumination at different cell temperatures using impedance spectroscopy technique. They are compared with the dark measurements. It is found that the cell capacitance is higher and cell resistance is lower under illumination than in dark for all cell terminal voltages. The cell capacitances at the corresponding maximum power point voltage (terminal) do not vary with temperature where as the cell resistance decreases. The cell capacitance under illumination is estimated from the dark cell capacitance and it is in good agreement with the measured illumination data.     

装饰照明的精神功能

本文拟从必更性、永恒性、时代性及科学技术四个角度论述了装饰照明的精神功能,指出装饰照明是工程技术与艺术设计相结合的—种新型艺术设计形式。     

Computer-Assisted Dispersion Analysis of Porosity Variation in Metals

The system analysis of porous materials is described analytically and its application is illustrated. The reliability of the method is estimated using the relations among the moments of the distribution function for micropore sizes. The method can be used to correlate the time variation of the experimental histograms and intravolume processes. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 177–183, September–October 2005.     

Gray-level corner detection

Besides reducing thick responses to thin, the application of non-maximum suppression to digital gradient magnitudes also improves the form of the edge response histogram, making the choice of thresholds easier.     

LED半导体照明的发展概述

半导体照明是一种新型的节能、环保、无辐射的绿色照明方式,LED作为下一代照明的主要光源,广泛的用于生产、生活的各个方面。本文概要的阐述了LED照明的现状、国内市场需求、及发展趋势。     

雍和宫法轮殿天然光环境解析

与现代建筑光环境的"宽敞明亮"绝然不同的是,在中国古建筑中,光环境通常以朦胧和含蓄为美。作为宗教建筑的雍和宫法轮殿,天然采光在建筑内部的作用不仅仅是满足人们视觉观察的需要,还有一个很重要的作用在于宗教气氛的烘托。本文从法轮殿天然光环境的营造特点和手法出发,对其内部的天然光环境从照度和亮度分布两个方面进行了定量分析,尝试在挖掘传统光文化的同时,对现代建筑照明设计理念提供一定的借鉴。     

Robust visual tracking via CAMShift and structural local sparse appearance model

This paper addresses issues in visual tracking where videos contain object intersections, pose changes, occlusions, illumination changes, motion blur, and similar color distributed background. We apply the structural local sparse representation method to analyze the background region around the target. After that, we reduce the probability of prominent features in the background and add new information to the target model. In addition, a weighted search method is proposed to search the best candidate target region. To a certain extent, the weighted search method solves the local optimization problem. The proposed scheme, designed to track single human through complex scenarios from videos, has been tested on some video sequences. Several existing tracking methods are applied to the same videos and the corresponding results are compared. Experimental results show that the proposed tracking scheme demonstrates a very promising performance in terms of robustness to occlusions, appearance changes, and similar color distributed background.     

Low-light image enhancement via deep Retinex decomposition and bilateral learning

Low-light images enhancement is a challenging task because enhancing image brightness and reducing image degradation should be considered simultaneously. Although existing deep learning-based methods improve the visibility of low-light images, many of them tend to lose details or sacrifice naturalness. To address these issues, we present a multi-stage network for low-light image enhancement, which consists of three sub-networks. More specifically, inspired by the Retinex theory and the bilateral grid technique, we first design a reflectance and illumination decomposition network to decompose an image into reflectance and illumination maps efficiently. To increase the brightness while preserving edge information, we then devise an attention-guided illumination adjustment network. The reflectance and the adjusted illumination maps are fused and refined by adversarial learning to reduce image degradation and improve image naturalness. Experiments are conducted on our rebuilt SICE low-light image dataset, which consists of 1380 real paired images and a public dataset LOL, which has 500 real paired images and 1000 synthetic paired images. Experimental results show that the proposed method outperforms state-of-the-art methods quantitatively and qualitatively.     

Lab scale optimization of various factors for photocatalytic hydrogen generation over low cost Cu0.02Ti0.98O2-δ photocatalyst under UV/Visible irradiation and sunlight

We have demonstrated earlier that maximum H₂ generated @ 1.167 l/h/m² over Cu_0.02Ti_0.98O_2-δ photocatalyst with apparent quantum efficiency, AQE of 7.5% and solar fuel efficiency, SFE of 3.9% under sunlight. With an aim to scale-up the solar photocatalytic hydrogen process to pilot plant, optimization studies at lab scale as well as in upscaled photoreactors were performed over Cu_0.02Ti_0.98O_2-δ, photocatalyst under UV/visible and sunlight. Cu_0.02Ti_0.98O_2-δ was synthesized by facile sol-gel route and characterized by relevant techniques. Several operational parameters were investigated in order to finalize the conditions which are most favourable for photocatalytic hydrogen yield. Factors such as photocatalyst loadings, v/v concentration of sacrificial reagent, replacement of methanol by industrial waste glycerol, role of different configuration of light source with reactor, effect of stirring during the photocatalytic reaction, effect of fluctuations of solar flux at hourly basis, illumination area on hydrogen yield were studied. Contribution of each factor in determining the hydrogen yield was quantified. Relative standard deviation in hydrogen yield as a function of each factor was estimated. Our findings suggest that in addition to catalyst loadings and sacrificial reagent, improved dispersion of photocatalyst obtained by stirring the reaction mixture in horizontal geometry resulted in enhanced H₂ yield. Hydrogen yield obtained at lab scale can be appropriately extrapolated with respect to illumination area instead of weight of photocatalyst. A relative standard deviation (RSD) of ± 3.82% and ± 4.53% in H₂ yield was calculated for sunny and cloudy days in time zone of 10.30–16.30 h IST. Deviation of H₂ yield was more on cloudy days and beyond 16:30 h. These studies have provided a daily window of 11:00–15:00 h to be utilized throughout the year for a commercial scaled up process, prohibiting the illumination during less productive hours of the day for shaping the improved economics of solar hydrogen generation. Our results obtained at lab scale would be useful to perform sunlight driven scaled –up photocatalytic process using low cost visible light efficient photocatalyst, Cu_0.02Ti_0.98O_2-δ.