808nm高效率激光二极管

目前808nm高效率激光二极管产品的转换效率只有50%左右,还有很大的提升空间。通过提高欧姆接触层浓度、界面渐变和波导层掺杂等方面的外延材料结构优化,减小附加电压和电阻值,设计制作了808nm大光腔应变量子阱外延材料;并制作了200μm发光区标准单管,提取了材料内部参数,材料内损耗iα为0.67cm-1,内量子效率iη为0.88;将圆片解理成2mm腔长的巴条进行腔面镀膜,并烧结成标准单管,25℃下单管电光效率达到61.1%;将巴条烧结到微通道载体上,制作成标准微通道水冷单条阵列,水温15℃110A下输出光功率126.6W,电光转换效率62.77%。     

低损伤ICP刻蚀技术提高GaN LED出光效率

首先分析了在制作GaN基LED时,采用干法刻蚀技术会对材料的表面和量子阱有源区造成损伤,影响了GaN基LED的内量子效率。针对这个问题,研究实验采用感应耦合等离子反应刻蚀(ICP-RIE)技术,分别选择了氯气/三氯化硼(Cl2/BCl3)气体体系和氯气/氩气(Cl2/Ar)气体体系,通过优化射频功率、ICP功率、气体流量以及相应的真空度,得到了良好的刻蚀端面,对于材料造成的损伤较低,得到更好的I-V特性。实验结果表明,采用低损伤的偏压功率刻蚀后制作的LED器件,出光功率提升一倍以上,同时采用Cl2/Ar气体体系,改善了器件的I-V特性,有效提高了LED的出光效率。     

光伏并网逆变器的高效控制器设计

提出了一种基于效率的新型光伏并网逆变器控制器,在这种新型的控制器中,直流侧电压不再是常量,而是被控制在可能的最低值.理论分析和实验结果证明这种新型控制策略能够提高系统整体效率.     

Using patents and publications to assess R&D efficiency in the states of the USA

Even with the USA spending the largest amounts in R&D, its share in total patent grants worldwide has been declining. This decline is also evident in its share of world scientific publications. These developments have been termed by some as the “American Paradox”. Extant research on R&D efficiency and technological innovation capability has considered the USA as a homogeneous entity and has not focused at the sub-national level. This paper analyses the R&D efficiency of 50 US states and the District of Columbia. R&D efficiency is calculated as the ratio of patents granted and scientific publications to R&D expenditures. Only 14 states out of the 51 regions are found to exhibit positive changes in R&D efficiency between 2004 and 2008. Comparing this performance with that of the BRICS nations over the same period we find that Brazil, India, China and South Korea show significant improvements in R&D efficiency with India taking the lead. This research identifies the states in the US with the highest R&D efficiency and presents benchmarks which can be followed by policy interventions. The paper highlights the importance of conducting analyses of R&D efficiency using patents and publications at the sub-national level for informed policy making.     

基于可靠度和效费比的特种车辆维修策略优化方法

为解决军用特种车辆维修周期设定不当导致的维修成本增加、效率降低等问题,提出一种单个更换周期不完全预防性维修计划的方法.采用役龄回退因子和故障率递增因子的混合故障率函数描述部件故障率变化趋势,引入惩罚机制来减少偶然因素引起的故障维修延时问题,以可靠度和维修方式效费比为约束条件确定维修周期.以某型军用车辆为例,通过预先设定的可靠度阈值确定预防性维修周期,根据计算不同预防性维修方式的效费比选择维修方式,生成维修方案,并与传统方案进行对比.结果表明:该方法能有效降低故障率,提高维修工作效率,减少维修资源浪费.     

Through‐the‐glass spectroscopic ellipsometry for analysis of CdTe thin‐film solar cells in the superstrate configuration

Polycrystalline CdS/CdTe thin‐film solar cells in the superstrate configuration have been studied by spectroscopic ellipsometry (SE) using glass side illumination. In this measurement method, the first reflection from the ambient/glass interface is rejected, whereas the second reflection from the glass/film‐stack interface is collected; higher order reflections are also rejected. The SE analysis incorporates parameterized dielectric functions ε for solar cell component materials obtained by in situ and variable‐angle SE. In the SE analysis of the complete cells, a step‐wise procedure ranks the fitting parameters, including thicknesses and those defining the spectra in ε, according to their ability to reduce the root‐mean‐square deviation between the simulated and measured SE spectra. The best fit thicknesses from this analysis are found to be consistent with electron microscopy. Based on the SE results, the solar cell quantum efficiency (QE) can be simulated without any free parameters, and comparisons with measured QE enable optical model refinements as well as identification of optical and electronic losses. These capabilities have wide applications in photovoltaic module mapping and in‐line monitoring. Copyright © 2016 John Wiley & Sons, Ltd.     

基于GIS的城市规划信息管理系统研究

我国正迈入快速城市化建设过程中,运用GIS技术手段来解决城市规划过程中的城市化建设进程信息整合管理,对于提高城市规划信息整合效率、避免重复建设、重叠规划、一库多建等城市规划问题有着积极意义。     

基于ZEMAX的气体光学吸收池的设计与优化

基于光谱吸收法的瓦斯实时监测系统的核心器件是开放式光学吸收池,根据矩阵传输理论和q参数的ABCD法则,设计了由2个相对的C-Lens组成的光学吸收池结构,并在ZEMAX的物理光学模式下实现仿真与优化。由理论分析得到结构的初步参数并在ZEMAX中进行优化,并使用合适的优化操作数对像差进行校正,经过逐步优化得到工作距离为100.39 mm的吸收池结构参数。高斯光束从一端光纤输出的束腰半经为5.2μm,经C-Lens聚焦和准直后,耦合到另一端光纤的束腰半经为5.48μm,该光学吸收池对甲烷近红外激光的耦合效率达到92%。通过实验验证了该光学吸收池的稳定性和高耦合效率,适用于甲烷气体的开放式光学气体传感和在线监测。     

一种新型双吸收层光探测器的设计和分析

PIN光探测器是光纤通信系统和网络中的关键器件.量子效率和响应带宽是衡量光探测器性能的重要指标,并且这两个参数都与器件的吸收层密切相关.为了提高光探测器的性能,提出了一种新型双吸收层光探测器(即PINIP结构),利用侧腐蚀工艺减小双吸收层光探测器吸收层的结面积.对其性能进行了理论研究,结果表明该器件的量子效率达到了93％,同时响应带宽达到了26 GHz,比传统结构的双吸收层光探测器提高了44％.     

硅微纳结构及其在新型太阳电池中的应用

综述了近年来各种硅微纳结构的特征和制备技术,介绍了其在新型太阳电池中的应用现状与前景.首先,阐述了硅微纳结构在传统p-n结、新型径向p-n结以及异质结太阳电池结构设计中的研究进展;其次,从光吸收增强、表面修饰及钝化的角度,分析了硅微纳结构太阳电池的增效措施;最后,提出了柔性硅微纳结构太阳电池开发的新思路.