Ligands in Lead Halide Perovskite Nanocrystals: From Synthesis to Optoelectronic Applications

Ligands are indispensable for perovskite nanocrystals (NCs) throughout the whole lifetime, as they not only play key roles in the controllable synthesis of NCs with different sizes and shapes, but also act as capping shell that affects optical properties and electrical coupling of NCs. Establishing a systematic understanding of the relationship between ligands and perovskite NCs is significant to enable many potential applications of NCs. This review mainly focuses on the influence of ligands on perovskite NCs. First of all, the ligands-dominated size and shape control of NCs is discussed. Whereafter, the surface defects of NCs and the bonding between ligands and perovskite NCs are classified, and corresponding post-treatment of surface defects via ligands is also summarized. Furthermore, advances in engineering the ligands towards the high performance of optoelectronic devices based on perovskite NCs, including photodetector, solar cell, light emitting diode (LED), and laser, and finally to potential challenges are also discussed.     

Unconventional Nanofabrication for Supramolecular Electronics

The scientific effort toward achieving a full control over the correlation between structure and function in organic and polymer electronics has prompted the use of supramolecular interactions to drive the formation of highly ordered functional assemblies, which have been integrated into real devices. In the resulting field of supramolecular electronics, self‐assembly of organic semiconducting materials constitutes a powerful tool to generate low‐dimensional and crystalline functional architectures. These include 1D nanostructures (nanoribbons, nanotubes, and nanowires) and 2D molecular crystals with tuneable and unique optical, electronic, and mechanical properties. Optimizing the (opto)electronic properties of organic semiconducting materials is imperative to harness such supramolecular structures as active components for supramolecular electronics. However, their integration in real devices currently represents a significant challenge to the advancement of (opto)electronics. Here, an overview of the unconventional nanofabrication techniques and device configurations to enable supramolecular electronics to become a real technology is provided. A particular focus is put on how single and multiple supramolecular fibers and gels as well as supramolecularly engineered 2D materials can be integrated into novel vertical or horizontal junctions to realize flexible and high‐density multifunctional transistors, photodetectors, and memristors, exhibiting a set of new properties and excelling in their performances.     

Application of K008 camera in diagnostics of shock and detonation waves

Results of tests of the K008 camera to determine its resistance to the action of factors that accompany gaseodynamic experiments, such as powerful electromagnetic, acoustic, and optical interference, and its application as a component of laser Doppler velocity meters of objects thrown by an explosion are presented. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 46–49, May, 2007.     

Velocity Reversal Systems: A Simple Friction Model for Telescopes

In this paper we experimentally characterize friction in an astronomical telescope and introduce a new model for capturing the observed behavior of friction in both the micro and macro displacement regimes of motion. The model is a modification of the LuGre model and is developed for velocity reversal systems like an astronomical telescope. The proposed model is represented with a pair of masses separated by a linear spring. This model is then employed to synthesize a feedback linearizable controller for the system. The simulation results for the proposed friction model in open loop are presented and validated with the experimental results. The stability aspects of the closed loop system with the modified friction model is then investigated. For estimating the unmeasurable states of the system used in feedback linearization, we discuss the observability of the system with the new model for friction.     

大射电望远镜精调稳定平台逆动力学分析

在获得了大射电望远镜精调稳定平台逆运动学参数的基础上,采用虚功原理对精调稳定平台进行了逆动力学分析,获得了进行高精度轨迹跟踪转矩控制所需的广义驱动力。为精调稳定平台实时运动控制,实现馈源高精度轨迹跟踪奠定了坚实的基础。     

余核飞行与ΔE—E望远镜双鉴别系统

设计和测试了一套在重离子熔合反应中同时测量蒸发剩余核的质量和电荷的飞行时间谱仪和ΔE-E望远镜双鉴别系统。实验结果表明,该系统对粒子的鉴别能力,Z分辨率好于25,质量分辨可达45。     

空间低温光学的新进展

介绍美国计划于２００２年发射的新型红外太空望远镜的低温系统、低温光学仪器的性能；主镜和二次镜的低温性能试验和材料选择。概述了９０年代初期发射的哈勃太空望远镜在实际运转时所存在的问题。     

大口径机械快门的设计与研制

针对大口径大视场望远镜的需求,设计了一种用于大口径望远镜的机械快门,其通光口径可达φ200mm,具有快速启停,定位准确,不同倾角下两叶片同开同闭等特点。机械结构设计中采用同步传送带和步进电机作为其传动装置具有平稳、速度快、定位准等特点;步进电机的控制、驱动设计中采用DSP发生PWM脉冲波控制电机的速度与位置;同时采用了指数型加减速曲线实现快门的快速启停。实验结果表明,研制的快门叶片打开或关闭时间达到0.2s,稳定性高,整体结构设计巧妙、紧凑,完全可以满足大口径望远镜的使用要求。