Solid Solvation Assisted Electrical Doping Conserves High-Performance in 500 nm Active Layer Organic Solar Cells

Organic solar cells (OSCs) process fascinating solution-printing capability to achieve low-cost and large-scale manufacture. However, the rapid power conversion efficiency (PCE) decay with active layer thickness enlargement inhibits the implement of OSCs’ potential advantages. To overcome the bottlenecks of PCE decay in thick active layer OSCs, the electrical doping with componential selectivity in bulk heterojunction (BHJ) film is achieved by introducing a solid solvation additive. Benefiting from the higher exciton splitting efficiency together with the longer drift (L_dr) and diffusion (L_diff) lengths, an OSC with 100 nm BHJ film demonstrates a PCE increment from 16.44% to 18.24% with prolonged dark and illuminated storage stabilities. Applying the solid solvation assisted (SSA) doping method in the OSCs with 500 nm active layer, the PCE significantly increases by 31.9%, from the original value of 11.79% to 15.55%. It further improves to 15.84% in a ternary blend thick-film device, which is the record value to the best of our knowledge. Besides, the SSA doping narrows the PCE gap between the 0.04 and 1 cm² devices. All improvements demonstrate the great potential of SSA doping for OSC commercial manufacture, since it optimizes the photovoltaic performance under all practical conditions of long-term, thick-film, and large-area.     

航空叶片打磨余量分析及轨迹生成

针对航空发动机叶片打磨加工前,叶身余量分布不均且较小的问题,提出一种基于毛坯点云配准的加工余量分析和自适应打磨轨迹生成方法。利用精确扫描测绘技术获取毛坯三维点云,形成了毛坯/零件数模二者点云配准方法;通过基准对齐、点云轮廓包含等条件约束,实现了毛坯三维加工余量分析;在余量分布点云基础上,通过截面获取加工点云轨迹,对轨迹点云进行珠链排序,将轨迹排序点有效化,计算出连续合适的打磨路径,实现自适应余量打磨。最后在Vericut软件中进行了打磨仿真,验证了提出方法的有效性。     

多泥沙电站高水头低出力水轮机水力设计策略

在多泥沙河流运行的水轮机,经常受到严重的泥沙磨损危害,机组的检修周期及运行寿命普遍较低。特别是对于高水头低出力要求的水轮机,机组磨损情况往往更为严重。为提高机组的抗磨损性能,水力设计阶段需专门考虑降低流道流速进而提高抗磨损性能的方法。本文以木扎提河三级水电站小水轮机的设计为例,综合考虑易磨损部位的相对流速及机组水力性能,确定了适用于高水头小流量多泥沙电站的水轮机水力设计策略。研究表明常规降低转速的方法对转轮及导叶出口流速、密封间隙内流动均有显著影响,转速降低的程度应通过流场对比分析合理确定。在高水头电站导叶尾部磨损更为严重,通过采取增大分度圆、优化导叶翼型及相对位置等可有效降低导叶后相对流速。采用长短叶片转轮,可大大降低转轮内部流速,提高在高含沙条件下机组的抗磨损性能,提升水轮机的运行稳定性及安全使用寿命。本文的研究可为多泥沙电站的水轮机设计策略提供有效参考。     

Study on the preparation and microstructure of a single-crystal hollow turbine blade

This paper studied the structural design of a ceramic core and a blade, ceramic core localization, shell preparation, casting process, core leaching technology, and the heat treatment process of a single-crystal hollow turbine blade. The results show that the single-crystal structure solidification sequence of the blade platform is consistent with the cooling sequence and the pulling-out direction of the blade. The primary dendrites were obviously enlarged with the increase of the blade thickness owing to the change in the local cooling rate. Besides, the γ′ phase had a high uniform size distribution ranging from 0.40 to 0.60?µm after heat treatment, and the cubic degree was more homogeneous in comparison with the as-cast microstructure, which are favorable for the superalloy structure. Moreover, γ′ phase size gradually increased and its quantity gradually reduced owing to the increase of the wall thickness in the growth direction.     

镍基单晶高温合金涡轮叶片缘板杂晶的研究进展

镍基单晶高温合金涡轮叶片缘板杂晶的出现严重影响叶片的力学性能,导致叶片报废。综述了关于缘板杂晶的形成本质的研究,总结了不同影响因素对缘板杂晶形成的影响及原因并概况了几种不同杂晶的控制方法,指出了以往研究中存在的问题,展望了未来研究的方向。     

基于激光点云数据的叶片型面三维重构

在四坐标叶片型面检测基础上,提出基于激光点云数据的叶片型面三维重构方法。激光位移传感器对叶片型面进行多视角扫描采样,快速采集叶片型面海量点云数据。运用由点到线到面的数学建模原理,先基于端点一阶导矢连续法拟合出光顺NURBS曲线,再依据分片能量法构建辅助曲面拟合出光顺NURBS曲面,最后对分片NURBS曲面进行统一描述,构造出精确光滑的叶片型面,实现叶片型面的三维重构。实验结果表明：采用该方法实现对各类叶片复杂型面的三维重构,重构误差均<0.015 mm,能够满足精密零件的测量需求。     

Numerical investigations on dynamic stall of low Reynolds number flow around oscillating airfoils

This paper presents a 2D computational investigation on the dynamic stall phenomenon associated with unsteady flow around the NACA0012 airfoil at low Reynolds number (Re_c ≈ 10⁵). Two sets of oscillating patterns with different frequencies, mean oscillating angles and amplitudes are numerically simulated using Computational Fluid Dynamics (CFD), and the results obtained are validated against the corresponding published experimental data. It is concluded that the CFD prediction captures well the vortex-shedding predominated flow structure which is experimentally obtained and the results quantitatively agree well with the experimental data, except when the blade is at a very high angle of attack.     

基于概率算法的混流式水轮机转轮叶片组合优化模型

讨论了混流式水轮机转轮厂内制作时各叶片组合形式对转轮静平衡的影响,并在VB环境下基于概率算法的寻优方式,建立了叶片组合优化模型。该模型以各叶片的不平衡力矩为目标函数,使用概率算法进行搜索寻优[1],找出可接受的满意解。应用该模型进行叶片组合优化设计,并与已有机组相比,优化设计结果有明显的优越性,证明了该组合优化模型的有效性和实用性。     

旋耕刀传感器的研究

设计了一种供旋耕刀测力用的延伸八角环传感器。该传感器具有良好的线性、较高的灵敏度及较小的滞后现象 ;各被测参数间的交互影响很小 ,可以忽略。     

便携式三坐标测量机在水轮机叶片修复中的应用研究

水轮机叶片是水轮机发电机组中的核心部件,由于工作的强度和环境影响,叶片极易磨损并且难以修复,更换叶片则成本巨大,故有效地对叶片进行修复则尤为重要。通过便携式三坐标测量机系统可对缺陷叶片进行逆向工程扫描,确立三维模型,还原其原始特性。根据系统软件处理三维比对得出叶片的缺陷部位偏差,从而进行修复指导,通过实践,证明三坐标测量机系统能对叶片修复给予指导并达到良好效果。