双闪耀光栅的计算机设计与制作方法

提出一种用计算机设计制作的双闪耀光栅，是在闪耀光栅和双频光栅基础上发展起来的一种新型光学元件，是由微闪耀光栅列阵组成的、兼有闪耀光栅和双频光栅的优良特性。     

基于网络编码的协作中继策略分析与对比

简要介绍了中继协作通信技术发展里程;在传统的2用户网络编码协作中继模型基础上,对2种不同的传输策略的系统性能进行了对比,并研究了功率优化分配问题。仿真表明,在系统总发射功率相同的情况下,策略二的系统性能明显优于策略一。     

空间光通信系统发射光束准直特性研究

提出一种前端直接耦合光纤平凸透镜的聚合物直光锥光准直系统.通过具体地对直光锥的端体结构参数进行优化设计以得到高耦合效率准直精度的直接耦合式聚合物直光准直系统.并利用光线传输理论和仿真实验,论证了直光锥的锥角和锥长准直效能的较大影响.结果表明,选择合适的锥角和锥长能达到十微弧度级准直精度,能较好地满足空间光通信系统远距离发射和接收对于光束质量的要求.此外,理论数值和仿真实验同样验证了该直接耦合式直光准直系统对于较大发散角的发散光束具有较好准直效果.     

多次散射激光雷达接收信号的模拟

MonteCarlo方法模拟多次散射激光雷达接收信号是一种经典方法，但这种方法的最大缺点是计算时间很长．为提高计算效率，本文在传统的半解析MonteCarlo方法的基础上，使用Henyey－Greenstein函数的修正公式来表示散射相位函数，计算出每个散射点处光子不发生进一步散射而直接到达接收机的概率．模拟结果显示，一、二、三次散射起主要作用，但随着海水衰减系数和接收机视场角的增大，高次散射对激光雷达的接收信号的作用也越来越强．     

铝衰减膜表面氧化对软X光透过率的影响与修正

对用不同方法制备的软Ｘ光激光实验用的Ａｌ衰减膜样品,用Ａｕｇｅｒ电子能谱（ＡＥＳ）结合氩离子束刻蚀进行了组分的表面和深度分布分析,结果表明表面氧化层主要由Ａｌ２Ｏ３组成,氧化达到饱和时的氧化层厚度≈７．５ｎｍ。由于在软Ｘ光波段内,氧的吸收系数比铝大一个多数量级,这一氧化层对软Ｘ光透过率的影响甚大。将ＡＥＳ测试结果作为参数,使用公式Ｉ＝Ｉ０·ｅｘｐ［－μ（Ｅ）·（ρｄ）］对Ｘ光透过强度进行修正。同步辐射软Ｘ光对样品透过率的直接测量表明,对于透过率大于２０％的Ａｌ膜,直接测量结果与按修正公式计算的结果在最大偏差１１％范围内符合。     

一种新型的太阳自动跟踪系统研究

为了最大限度的利用太阳能,采用自动跟踪太阳的方式以获得更多的能量。简要介绍了现有的几种主要跟踪方式,光电探测器跟踪方式容易受天气条件干扰,时钟跟踪方式有累积误差或者因数据库庞大导致反应变慢等缺点。提出了一种时钟跟踪与光电探测器跟踪相结合的双轴跟踪方式,方位角采用时钟跟踪,俯仰角采用四象限光电探测器跟踪,控制核心选用ATmega16单片机。该跟踪方式结合这两种跟踪方式的优点,很好地克服了两者的缺点。实验表明,本系统转动精度高,工作稳定性好,太阳能接收损失小。     

Elucidating the Origins of Subgap Tail States and Open‐Circuit Voltage in Methylammonium Lead Triiodide Perovskite Solar Cells

Recombination via subgap trap states is considered a limiting factor in the development of organometal halide perovskite solar cells. Here, the impact of active layer crystallinity on the accumulated charge and open‐circuit voltage (V_oc) in solar cells based on methylammonium lead triiodide (CH₃NH₃PbI₃, MAPI) is demonstrated. It is shown that MAPI crystallinity can be systematically tailored by modulating the stoichiometry of the precursor mix, where small quantities of excess methylammonium iodide (MAI) improve crystallinity, increasing device V_oc by ≈200 mV. Using in situ differential charging and transient photovoltage measurements, charge density and charge carrier recombination lifetime are determined under operational conditions. Increased V_oc is correlated to improved active layer crystallinity and a reduction in the density of trap states in MAPI. Photoluminescence spectroscopy shows that an increase in trap state density correlates with faster carrier trapping and more nonradiative recombination pathways. Fundamental insights into the origin of V_oc in perovskite photovoltaics are provided and it is demonstrated why highly crystalline perovskite films are paramount for high‐performance devices.     

溶胶-凝胶提拉法制备Mgx Ni1-xO薄膜与表征

利用溶胶-凝胶提拉法在石英玻璃衬底上制备出吸收边波长位于地球表面太阳光谱日盲区(240～280nm)内的MgxNi1-xO薄膜.XPS和XRD结果显示,MgxNi1-xO在1000℃下形成具有立方结构的固溶体;紫外-可见吸收谱结果表明,MgxN1-xO吸收边随着Mg含量的变化而发生改变,当Mg含量x在0.2～0.3之间时,薄膜的吸收边波长在248～276nm范围内可调;光电响应测试结果表明,MgxNi1-xO薄膜(x=0.3)对太阳光不敏感,而对波长为254nm的紫外光具有很好的光电导特性,光照前后薄膜电阻变化率达40%,因此,我们可以认为MgxNi1-xO(x=0.2～0.3)薄膜材料有望应用于日盲区的紫外探测.     

MEMS压阻式三轴加速度传感器的双路循环电桥检测法

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.