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121.
耦合光学系统是端面抽运固体激光器中不可缺少的部分,其成像质量的优劣直接影响到激光器转换效率的高低.以激光二极管(LD)端面抽运Nd∶YVO4/LBO 457 nm蓝光激光器为例,分别采用两种不同结构的准直聚焦透镜组合作为耦合光学系统,分析其对抽运光的成像情况以及对端面抽运固体激光器光束质量和输出功率的影响,在激光器的抽运功率和谐振腔的参数完全相同的情况下,改进的四片式耦合光学系统使激光器输出的光束质量得到了明显改善,同时极大地提高了倍频输出功率,在30 W的抽运功率下,得到了4.3 W的连续457 nm蓝光激光输出,光-光转换效率达到13.7%. 相似文献
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列车速度的不断提高增大了车轮的磨损,加快了车轮直径的变化,给列车运行带来了安全隐患。提出了一种采用激光动态测量车轮直径的方法,介绍了使用单个激光位移传感器和两个激光位移传感器动态测量车轮直径的工作原理,并对影响测量精度的主要误差因素进行了分析和仿真计算。结果表明,采用两个激光位移传感器的测量方案可有效克服车轮运动过程中定位误差对测量的影响。经过现场测试,研制的激光测量装置的测量精度为±0.38 mm(σ)满足现场要求,实现了列车在正常运行过程中对其直径进行动态在线测量。 相似文献
124.
Rapid Assembly of Large Scale Transparent Circuit Arrays Using PDMS Nanofilm Shaped Coffee Ring 下载免费PDF全文
Yiwei Li Weixia Zhang Jiliang Hu Yachao Wang Xiaojun Feng Wei Du Ming Guo Bi‐Feng Liu 《Advanced functional materials》2017,27(11)
Rapid and precise assembly of functional nanoparticles into well‐defined structures in large scale is motivated by broad fields. In this study, large‐scale transparent conductive circuit arrays are rapidly self‐assembled by simply pipetting a gold nanoparticles suspension onto a PDMS nanofilm patterned substrate with distinct hydrophilic/hydrophobic areas. The solution firstly self‐confines into predefined hydrophilic geometries, followed by assembly of nanoparticles into well‐defined circuits with 1D patterns by coffee ring effect. Submicrometer height and submicrometer‐ to micrometer‐width circuit arrays with various shapes are precisely generated by varying the PDMS nanofilm patterns. Thousands of circuits with different geometries are self‐assembled simultaneously within 1 min. The conductive circuits show good optical transparency up to 95%. After being transferred into PDMS elastomer sheet by encapsulating, the circuits remain highly conductive during bending and stretching. With the advantages of high‐throughput, equipment‐free, scalability, and precise control, this technique will open an avenue for fabricating large‐scale functional materials for applications in electronics, optoelectronics, and healthcare devices. 相似文献
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介绍了直接探测瑞利测风激光雷达工作及风速反演的原理,说明了激光雷达接收机的内部结构及工作情况。为修正雷达接收机中分光片分束比、单光子计数器探测率等参数与设计值的偏差所导致的风速测量误差,提出了随光强变化比较两信号通道的计数值的接收机校准方案。实验测得了校准系数随信号通道信号强度的变化关系。在弱光下该系统两信号通道性能差异小于25%。在当前系统的标准具透过率条件和对称的风场扫描合成方式下,接收机校准只对系统透过率曲线和径向风速的测量有较大影响,对合成风场没有影响。 相似文献
127.
红外光学系统冷反射指制冷型探测器看到自身的反射像,它严重影响红外光学系统的图像质量。光学系统设计中控制冷反射的强度往往与提高光学系统像质和满足边界要求之间是矛盾的。详细介绍了冷反射强度仿真分析和评估方法,提出了冷反射辐射的信号与系统噪声之比的定量计算模型。对两套红外系统的冷反射强度进行了仿真分析和实验测试。研究结果表明,冷反射强度实验测试与仿真计算结果一致,冷反射仿真分析和定量计算在光学设计中能够有效地评估冷反射强度,保证光学系统设计质量。 相似文献
128.
Erpeng Li Enbing Bi Yongzhen Wu Weiwei Zhang Linchang Li Han Chen Liyuan Han He Tian Wei‐Hong Zhu 《Advanced functional materials》2020,30(7)
All organic charge‐transporting layer (CTL)‐featured perovskite solar cells (PSCs) exhibit distinct advantages, but their scaling‐up remains a great challenge because the organic CTLs underneath the perovskite are too thin to achieve large‐area homogeneous layers by spin‐coating, and their hydrophobic nature further hinders the solution‐based fabrication of perovskite layer. Here, an unprecedented anchoring‐based coassembly (ACA) strategy is reported that involves a synergistic coadsorption of a hydrophilic ammonium salt CA‐Br with hole‐transporting triphenylamine derivatives to acquire scalable and wettable organic hole‐extraction monolayers for p–i–n structured PSCs. The ACA route not only enables ultrathin organic CTLs with high uniformity but also eliminates the nonwetting problem to facilitate large‐area perovskite films with 100% coverage. Moreover, incorporation of CA‐Br in the ACA strategy can distinctly guarantee a high quality of electronic connection via the cations' vacancy passivation. Consequently, a high power‐conversion‐efficiency (PCE) of 17.49% is achieved for p–i–n structured PSCs (1.02 cm2), and a module with an aperture area of 36 cm2 shows PCE of 12.67%, one of the best scaling‐up results among all‐organic CTL‐based PSCs. This work demonstrates that the ACA strategy can be a promising route to large‐area uniform interfacial layers as well as scaling‐up of perovskite solar cells. 相似文献
129.
Lei Tao Anyang Hu Zhijie Yang Zhengrui Xu Candace E. Wall Alan R. Esker Zhifeng Zheng Feng Lin 《Advanced functional materials》2020,30(31)
Porous carbon scaffolds can host lithium (Li) metal anodes to potentially enable stable Li metal batteries. However, the poor Li metal wettability on the carbon surface has inhibited the uniform distribution of metallic Li on most carbon scaffolds. Herein, this work reports a lithiophilic top layer through mild surface ozonolysis and ammoniation methods can universally facilitate the infiltration of liquid Li metal into most carbon matrices. Based on this finding, thin, a lightweight Li@carbon film (CF) composite anode with a high practical capacity of 3222 mAh g?1 and suppressed volume expansion and dendrite formation is reported. It is observed that the deep stripping/plating pre‐cycling yields dense, trunky Li metal in the Li@CF composite, which allows for favorable long‐term cycling performance. The full cell combining the thin Li@CF composite anode and a high‐mass‐loading, cobalt‐free cathode can deliver high reversible capacity, good cycle stability, and good rate capability in the conventional carbonate electrolyte. The present study further establishes the relationship between lithiophilicity and hydrophilicity for carbon materials as well as provides insights into improving the liquid Li metal infiltration into other carbon scaffolds. 相似文献
130.