A solar concentrator with two reflection mirrors designed by using a ray tracing method

Solar concentrators with two reflection mirrors are numerically designed by using a ray-tracing method to obtain higher concentration ratio when the concentrator tracing error is existed. The primary reflection mirror adopts paraboloidal mirror; the secondary mirror adopts hyperboloidal or ellipsoidal mirror. The optimal designed shape parameters for hyperboloidal and ellipsoidal cases are obtained, respectively. It is found that, when the concentrator tracing errors are 0°, 0.5° and 1°, the concentration ratios for hyperboloidal case are about 5837, 1954 and 1127 at f-number₁=0.22 and NA₂=0.62 and the one for ellipsoidal case are about 5860, 1993 and 1193 at f-number₁=0.25 and NA₂=0.62, respectively. Obviously, the concentrator with the ellipsoidal mirror is slightly better than the one with the hyperboloidal mirror.     

Design of a solar concentrator combining paraboloidal and hyperbolic mirrors using ray tracing method

A solar concentrator combining primary paraboloidal and secondary hyperboloidal mirrors is numerically designed by using the ray tracing method to obtain higher concentration ratio when the concentrator tracing error exists. It is found that, when the concentrator tracing errors are 0.5° or 1°, the concentration ratios are about 2027 or 1220 without the detector in the radial-direction, and the concentration ratios are about 5447 or 4701 with the detector in the radial-direction. It is shown that such method can increase the concentration solar flux by two folds when the concentrator tracing error exists. Obviously, it is an effective method to reduce the effect of concentrator tracing error even when the angle of concentrator tracing error is considered. In addition, when the angle of concentrator tracing error is small than 1°, a set of mirror shapes is suggested where the primary mirror has a f-number of 0.22 and the secondary mirror has a numerical aperture (NA) of 0.61.     

Solar system for exploitation of the whole collected energy

An innovative architecture for the exploitation of the whole collected solar energy is described. A sun pointing optical concentrator focuses the received energy, containing the part of the required solar spectrum, in a low loss optical fibre transmission line. The optical panel is small in size and able to follow the sun in order to collect the maximum of its energy. The support is flat, 5 mm thick and includes four optical concentrators. The efficiency of the optical system depends on the optical configuration and on the material utilised for the optical components. Single commercial connector to the fixed fibres connects the fibre optics’ four free ends. The energy is therefore properly transported to any user's end with an easy installation. The system was experimented for lightening, during the day, dissipated in a dark load in order to produce heat in some equipment and for photovoltaic applications. The total efficiency of the system was between 68% and 72%. Once the solar energy reaches the end of the transmission line, it can be addressed to the required utilisation by means of an optical switch, which redirects the sunlight towards the desired applicator. This procedure allows utilising the 100% of the sun-collected energy. Since the size of the panel was small, it can be placed, on the roof, on the garden, on the window-sill, on the field and on all sides exposed to sunlight.     

大型双曲面次镜面形检测技术现状及发展趋势

随着以双曲面为次镜的两镜光学系统在天文和空间光学等领域的应用日趋广泛,双曲面次镜的口径和相对口径越来越大,由此对双曲面次镜的面形检测技术提出了很高的要求。本文基于国外有代表性的双曲面次镜参数分析了其基本特征和发展趋势,重点介绍了国外大型双曲面次镜的面形检测技术,并对其中的关键技术进行了分析。同时,概述了国内双曲面次镜检测技术现状。最后,总结和展望了大型双曲面次镜面形检测技术发展趋势。提出今后一段时间内,高均匀性的光学透射材料,高精度、大口径的辅助元件以及基于子孔径拼接的检测方法和数据处理方法是该领域的研究重点。     

Optical characterisation of solar concentrator

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Porous silicon layers prepared by electrochemical etching for application in silicon thin film solar cells

In this paper, multilayer structures of porous silicon were fabricated by using electrochemical etching and characterized for its optical properties and surface morphology. Samples of monolayer of porous silicon were grown to study the characteristics of porous layer formation with respect to applied current density, etching time and hydrofluoric acid concentrations. Photoluminescence peaks of red emission at wavelength 695 and 650 nm were observed from multilayer porous silicon structures. By atomic force microscopy measurement, hillocks like surface were clearly observed within the host material, which confirmed the formation of pores.     

光电系统中铍反射镜的发展与应用

综述了光电系统中铍反射镜常用材料的特性、加工方法、发展现状及最新应用。首先,介绍了目前国外铍反射镜常用材料的性能,铍反射镜基底制备、机械加工和光学加工等方面的发展现状。然后,以詹姆斯韦伯太空望远镜和F-9120航空远距离可见/红外双波段侦察相机为例,重点介绍了铍以及铍铝合金在空间和航空光电系统的反射镜及光机支撑结构上的最新应用。最后,对铍和铍铝合金在光电系统中的未来发展和应用前景提出了展望。     

太阳极紫外成像光谱仪光学系统设计

在极紫外波段对太阳进行超光谱成像观测是研究太阳上层大气,日冕中等离子物理特性的重要手段。依据太阳极紫外成像光谱仪的应用,结合国内外极紫外成像光谱仪发展现状,制定了太阳极紫外成像光谱仪的性能指标。通过比较各种光学结构的优缺点,选择望远镜与光谱仪组合的结构。讨论并选择了可用的基本元器件,望远系统采用离轴抛物面反射镜,分光器件为高密度超环面等间距光栅。设计出符合指标的光学系统。最后给出了太阳极紫外成像光谱仪的设计过程、详细参数与结果。光学系统的工作波段为17.0～21.0nm,视场是1 228″×1 024″,空间分辨率达到0.8arcsec.pixel-1,光谱分辨率约为0.001 98nm.pixel-1,系统总长度约为2.8m。     

不同类型细胞穿膜肽二级结构特征研究

细胞穿膜肽是一类能以受体依赖或非受体依赖方式介导胞吞作用的小分子短肽,能够携带不同分子穿过细胞膜,这一特性使细胞穿膜肽成为一种有效的运输载体,为药物靶向治疗提供了新希望.本文从生物信息角度针对不同长度区间、运输不同类型分子细胞穿膜肽之间的异同二级结构特征进行了系统研究,同时进一步对不同穿膜方式对应的细胞穿膜肽二级结构特征进行了对比研究,结果表明不同类型细胞穿膜肽之间在二级结构组成上具有不同程度差异特征,为今后揭示细胞穿膜肽相关分子结构机制奠定可靠的理论基础.     

氧碘化学激光器谐振腔腔镜失调测量与研究

为保证氧碘化学激光器谐振腔的腔镜失调测量结果的可靠性和准确性,建立了使用自准直仪间接测量腔镜失调的方法。测量结果表明,热辐射是引起腔镜失调并造成光束漂移的主要原因,通过采取措施,可以使腔镜失调明显减小。同时证明了该测量方法是可靠的、合理的。     

太阳模拟器用光学积分器设计

针对传统太阳模拟器普遍存在辐照均匀度较低的缺陷,改进设计了一种可以有效提高太阳模拟器辐照均匀度的光学积分器.介绍了该光学积分器的组成和工作原理;阐述了光学系统的优化设计技术;对其光机结构进行合理化设计,并使用ansys软件对光机结构进行热分析.最后,利用lightTools软件对太阳模拟器系统进行模拟仿真.结果表明:使用所设计的光学积分器后,太阳模拟器辐照不均匀度明显降低,在Φ60 mm范围内小于±1%,在Φ(60~200)mm范围内小于±2%.该结果与实际检测结果一致,能够满足高准确度的使用要求.     

氧碘化学激光器谐振腔腔镜失调测量与研究

 为保证氧碘化学激光器谐振腔的腔镜失调测量结果的可靠性和准确性，建立了使用自准直仪间接测量腔镜失调的方法。测量结果表明，热辐射是引起腔镜失调并造成光束漂移的主要原因，通过采取措施，可以使腔镜失调明显减小。同时证明了该测量方法是可靠的、合理的。     

Development of sulphurized SnS thin film solar cells

Thin films of tin sulphide (SnS) have been grown by sulphurization of sputtered tin precursor layers in a closed chamber. The effect of sulphurization temperature (T_s) that varied in the range of 150–450 °C for a fixed sulphurization time of 120 min on SnS film was studied through various characterization techniques. X-ray photoelectron spectroscopy analysis demonstrated the transformation of metallic tin layers into SnS single phase for T_s between 300 °C and 350 °C. The X-ray diffraction measurements indicated that all the grown films had the (111) crystal plane as the preferred orientation and exhibited orthorhombic crystal structure. Raman analysis showed modes at 95 cm⁻¹, 189 cm⁻¹ and 218 cm⁻¹ are related to the A_g mode of SnS. AFM images revealed a granular change in the grain growth with the increase of T_s. The optical energy band gap values were estimated using the transmittance spectra and found to be varied from 1.2 eV to 1.6 eV with T_s. The Hall effect measurements showed that all the films were p-type conducting nature and the layers grown at 350 °C showed a low electrical resistivity of 64 Ω-cm, a net carrier concentration of 2 × 10¹⁶ cm⁻³ and mobility of 41 cm² V⁻¹ s⁻¹. With the use of sprayed Zn_0.76Mg_0.24O as a buffer layer and the sputtered ZnO:Al as window layer, the SnS based thin film solar cell was developed that showed a conversion efficiency of 2.02%.     

空间遥感器中大口径SiC主镜的轻量化设计

考虑到反射镜质量、尺寸对载荷敏感度、加工困难程度和总成本的影响,阐述了对空间遥感器大口径主镜进行轻量化设计与优化的必要性。叙述了主镜轻量化技术的一般规律,对几种轻量化方式进行了比较并给出了网格筋大小的确定公式。结合具体工程的主镜设计,针对SiC材料的空间反射镜提出了一种背部半封闭、三角形孔的轻量化形式,用迭代方法完成了轻量化设计,并制作了660 mm轻量化SiC反射镜。提出的设计方式解决了单种轻量化方式存在的不足,使单镜满足了质量小、刚度大的要求,为今后大口径SiC主镜的轻量化技术提供了借鉴和参考。     

New issue of GaN nanoparticles solar cell

This study involves the synthesis of gallium nitride (GaN) nanoparticles (NPs) under different low temperatures using a simple chemical method. The nanoparticles are spin coated on Si substrate to fabricate the solar cell. The FESEM images obtained indicate the presence of cubic GaN nanoparticle with average diameter of 50 nm synthesized at 90 °C. The spin coating technique deposited n-GaN NPs/Si(111) produced a heterojunction solar cell with fill factor of 0.56 and conversion efficiency of 2.06%. Based on these results, this study proposes a novel low cost technique for the fabrication of GaN NPs solar cells.     

Integrative optimization of chirped mirrors for intracavity dispersion compensation

A new integrative optimization of three chirped mirrors for precise broadband intracavity group delay dispersion compensation in ring cavity is proposed. Simulation demonstrates that the residual group delay dispersion ripples of these three chirped mirrors are less than 25 fs² for most of the wavelengths from 600 to 1200 nm. Pulse evolution simulation shows that these three matched chirped mirrors compensate the group delay dispersion in the Ti:Sapphire ring cavity laser well to obtain an octave-spanning spectrum.     

激光器腔镜夹持方式对热变形的影响

 分析了当前大功率激光器腔镜采用的几种夹持方式特点，采用有限元软件计算了腔镜不同夹持方式下的镜面热变形和镜体最大应力，并对两种夹持方式下的应力破坏进行了分析。发现夹持方式对大功率激光器腔镜镜面变形影响很大，镜体边界沿径向固定的压圈法效果优于沿轴向固定的弹性压板法。     

The effect of sulphur amount in sulphurization stage on secondary phases in Cu2SnS3(CTS) films

Cu₂SnS₃ is a promising absorber for green thin film solar cells because of its suitable optoelectrical properties and environment friendly components. In this study, CTS films were prepared by sulphurization of stacked metallic precursors deposited by thermal evaporation. Some physical properties were investigated by changing the amount of sulphur used in sulphurization stage. Highly crystalline tetragonal-CTS phase was obtained for all samples. However, Cu₃SnS₄ and CuS secondary phases were also determined at low amounts. Cu/Sn ratio approached to desired stoichiometry of CTS with increasing sulphur amount. Absorption spectra showed that there are two discrete absorption regions that are related to tetragonal-CTS and secondary phases. Thickness and optical constants were determined using spectroscopic ellipsometry. Atomic force microscope was used to evaluate the effects of sulphur amount on the morphology of CTS films. As a result, this study suggests a way of minimizing the secondary phases to obtain single phase tetragonal CTS.     

激光器腔镜夹持方式对热变形的影响

分析了当前大功率激光器腔镜采用的几种夹持方式特点,采用有限元软件计算了腔镜不同夹持方式下的镜面热变形和镜体最大应力,并对两种夹持方式下的应力破坏进行了分析。发现夹持方式对大功率激光器腔镜镜面变形影响很大,镜体边界沿径向固定的压圈法效果优于沿轴向固定的弹性压板法。