太阳能光热发电技术综述

从经济、环境和社会角度来看,目前的能源供应和使用趋势明显不是可持续的。太阳能聚光光热发电（CSP）技术给拥有充足光照资源的地区带来了希望。太阳能聚光光热发电（CSP）技术可为法向直接日射辐照度（DNI）强的地区提供低碳、可再生能源。该文在简要分析太阳能光热发电技术现状基础上,介绍了太阳能光热发电当前的主要技术以及如何提高太阳能热发电实用性的相关技术。通过使用储热系统、后备燃料或带燃料的混合动力发电可以提高太阳能热发电的实用性。     

Tuning nanoporous anodic alumina distributed-Bragg reflectors with the number of anodization cycles and the anodization temperature

The influence of the anodization temperature and of the number of applied voltage cycles on the photonic properties of nanoporous anodic alumina-based distributed-Bragg reflectors obtained by cyclic voltage anodization is analyzed. Furthermore, the possibility of tuning the stop band central wavelength with a pore-widening treatment after anodization and its combined effect with temperature has been studied by means of scanning electron microscopy and spectroscopic transmittance measurements. The spectra for samples measured right after anodization show irregular stop bands, which become better defined with the pore widening process. The results show that with 50 applied voltage cycles, stop bands are obtained and that increasing the number of cycles contributes to enhancing the photonic stop bands (specially for the case of the as-produced samples) but at the expense of increased scattering losses. The anodization temperature is a crucial factor in the tuning of the photonic stop bands, with a linear rate of 42 nm/°C. The pore widening permits further tuning to reach stop bands with central wavelengths as low as 500 nm. Furthermore, the results also show that applying different anodization temperatures does not have a great influence in the pore-widening rate or in the photonic stop band width.     

1″级四面体组合合作目标激光雷达散射截面实验与理论研究

Cr:LiSAF是一种高效率、宽发射光谱及寿命时间长的激光晶体。Cr:LiSAF激光器发展极快,现已提供从可见到近红外区域全固体化宽带可调谐激光及超短脉冲激光。     

Performance evaluation of a small scale indirect solar dryer with static reflectors during non-summer months in the Saurashtra region of western India

This paper reports the design and development of an indirect, natural convection batch-type solar dryer fitted with North–South reflectors. With the help of the reflectors the collector efficiency without load was enhanced from 40.0% to 58.5% under peak solar irradiation conditions during a typical day in January in Bhavnagar, Gujarat, India. The corresponding computed values based on heat transfer equations were 36.5% and 50.3%. The desired extent of drying (ca. 12%, wet basis) of ‘papad’ – a popular Indian wafer – could be achieved within 5 h in this static dryer having 1.8 m² area of the collector and computed loading capacity of 3.46 kg. The initial and average values of the drying efficiency were 16.3% and 4.1%, respectively. The drying performance data could be fitted to the diffusivity equation with effective diffusivity value of 3.9 × 10⁻⁹ m² s⁻¹. Despite the high collector efficiency achieved, the average drying efficiency was low on account of under-loading of the dryer, as evident from the increase in drying efficiency to 13% in a smaller dryer loaded with the same amount of wet papad.     

一种激光能见度仪设计的新方法

该方法改进了传统透射式仪和散射式仪的结构,利用反射镜构成开放气室实现了激光往返式透射法测量方案,运用位移调节器实现了差分测量大气消光系数。基于此方法设计的激光测量系统不仅兼容了透射法的测量原理和后向散射法的单端收发等优点,还具有抗环境污染能力强和测量灵敏度可调等独特优点。本文对该系统进行了详尽的理论分析,同时,还设计了传感器的结构,精选了性能指标优异的光学元件和估算了测量精度,为仪器的硬件实现提供了重要参考方案。     

>16% thin‐film epitaxial silicon solar cells on 70‐cm2 area with 30‐µm active layer,porous silicon back reflector,and Cu‐based top‐contact metallization

We demonstrate the use of a copper‐based metallization scheme for the specific application of thin‐film epitaxial silicon wafer equivalent (EpiWE) solar cells with rear chemical vapor deposition emitter and conventional POCl₃ emitter. Thin‐film epitaxial silicon wafer equivalent cells are consisting of high‐quality epitaxial active layer of only 30 µm, beneath which a highly reflective porous silicon multilayer stack is embedded. By combining Cu‐plating metallization and narrow finger lines with an epitaxial cell architecture including the porous silicon reflector, a J_sc exceeding 32 mA/cm² was achieved. We report on reproducible cell efficiencies of >16% on >70‐cm² cells with rear epitaxial chemical vapor deposition emitters and Cu contacts. Copyright © 2011 John Wiley & Sons, Ltd.     

小型轻质长条反射镜挠性支撑方案研究

光学反射镜支撑结构良好的尺寸稳定性是保证其成像的关键因素,对小型轻质长条反射镜来说,反射镜自身的特点是长宽比较大,不利于支撑的展开,这必然会给反射镜的支撑结构设计带来困难。针对这种情况,本文对某型反射镜的支撑进行了研究,提出了单点挠性的概念,并对具体结构进行了细致的研究。工程分析表明,这种支撑可以很好地保证反射镜在静力学、热环境下镜面具有较高成像质量,而其支撑自身在一定的动态环境下不会破坏。这种支撑结构不仅具有静态、动态的尺寸稳定性,而且重量较轻,适合小型空间遥感器使用。     

几种规则反射体回波幅度计算公式的论证

应用人们熟知的物理概念和数学知识，求证出了圆盘源远场中几种规则反射体，如平底孔底面、球孔、长横孔和短横孔等的回波幅度计算公式。讨论了公式推导过程中的近似考虑的必要性。