Up?Scalable Fabrication of -SnO2 with Multifunctional Interface for High Performance Perovskite Solar Modules

Tin dioxide -(SnO2) has been demonstrated as one of the promising electron transport layers for highefficiency perovskite solar cells (PSCs). However, scalable ...     

裂解/烧焦切换操作的双辐射段裂解炉的数值模拟

用Gambit软件对双辐射段裂解炉进行几何建模和网格划分,选择计算流体力学软件Fluent的标准k-ε湍流模型、有限速率/涡耗散燃烧模型和P1辐射模型,对裂解炉辐射段和对流段进行数值模拟计算。模拟计算结果表明,裂解辐射段的烟气温度高于烧焦辐射段;在炉管中心面处,裂解辐射段的压力略高于烧焦辐射段,烟气流动的线速度明显大于烧焦辐射段;两个辐射段的炉管管壁温度分布不一致。尽管裂解辐射段的横跨段出口面烟气平均温度高于烧焦辐射段,但高温烟气没有流入烧焦辐射段且流向对流段的烟气温度场随着对流段高度上升逐渐均匀,该计算结果说明了双辐射段裂解炉的裂解/烧焦切换操作是可行的,并可进一步优化双辐射段裂解炉的结构和操作。     

一个改进的N元自适应模式识别系统开发工具

N元自适应模式识别系统开发工具NIRSS是一个通用开发工具.它可以对多种N元自适应模式识别系统模型的体系结构和应用对象进行试验研究.本文针对该系统的不足,提出采用修改编译模式并利用EMS技术扩大存贮容量的方法,使其具有处理高维数模式数据(如图像)的能力.实验证明,改进工作是成功且有意义的.     

基于统计分析的数据链电磁环境适应性研究

通过对无人机数据链在零均值和非零均值电磁干扰环境条件下的电磁兼容性概率函数的研究,检验系统在给定信号条件下的电磁兼容性概率,可以客观地反映出无人机数据链电磁环境适应能力的高低.从总体性能检测或环境适应性分析的角度考虑,利用具有可比性的传统误码率分析方法的验证及其取得的一致性结论,清晰地表明该统计方法的有效性.     

Recent Advances in Optical Engineering of Light‐Emitting Electrochemical Cells

Since the first demonstration of light‐emitting electrochemical cells (LECs) in 1995, much effort has been made to develop this technology for display and lighting. A common LEC generally contains a single emissive layer blended with a salt, which provides mobile ions under a bias. Ions accumulated at electrodes facilitate electrochemical doping such that operation voltage is low even when employing high‐work‐function inert electrodes. The superior properties of simple device architecture, low‐voltage operation, and compatibility with inert metal electrode render LECs suitable for cost‐effective light‐emitting sources. In addition to enormous progress in developing novel emissive materials for LECs, optical engineering has been shown to improve device performance of LECs in an alternative way. Light outcoupling enhancement technologies recycle the trapped light and increase the light output from LECs. Techniques to estimate emission zone position provide a powerful tool to study carrier balance of LECs and to optimize device performance. Spectral tailoring of the output emission from LECs based on microcavity effect and localized surface plasmon resonance of metal nanoparticles improves the intrinsic emission properties of emissive materials by optical means. These reported optical techniques are overviewed in this review.     

微机电系统关键技术及其研究进展

微机电系统(MEMS)是在微电子技术的基础上兴起的一个多学科交叉的前沿领域,集约了当今科学技术发展的许多尖端成果,在汽车电子、航空航天、信息通讯、生物医学、自动控制、国防军工等领域应用前景广阔.该文介绍了微机电系统发展的背景与基础理论研究,综述了微机电系统所涉及的器件设计、制作材料、3大加工工艺(硅微机械加工、精密微机械加工与光刻、电铸和注塑(LIGA)技术)、微封装与测试等关键技术,总结了微机电系统在微纳传感器、微执行器、微机器人、微飞行器、微动力能源系统、微型生物芯片等方面的典型应用,最后指明了MEMS技术的发展趋势,有望在近几十年将大量先进的MEMS器件从实验室推向实用化和产业化.     

基于莫尔光纤光栅的带通滤波器

通过改变写入条件,控制两次曝光量、光纤拉伸大小和起始位相差等参数,可以调整π相移点的位置,制作出符合要求的相移光纤光栅.用同一块均匀相位板在普通的SMF-28单模光纤上制作出了3 dB带通宽度分别为0.01和0.5 nm的带通滤波器,符合理论模拟的计算结果.利用啁啾量为10 nm/cm,长度为1 cm的啁啾相位掩模板制作了7信道的带通滤波器.     

Modeling the Sojourn Time of Items for In-Networ Cache Based on LRU Policy

To reduce network redundancy, in- network caching is considered in many future Internet architectures, such as Information Centric Networking. In in-network caching system, the item sojourn time of LRU （Least Recently Used） replacement policy is an important issue for two reasons： firstly, LRU is one of the most common used cache policy; secondly, item sojourn time is positively correlated to the hit probability, so this metric parameter could be useful to design the caching system. However, to the best of our knowledge, the sojourn time hasn＇t been studied theoretically so far. In this paper, we first model the LRU cache policy by Markov chain. Then an approximate closed- form expression of the item expectation sojourn time is provided through the theory of stochastic service system, which is a function of the item request rates and cache size. Finally, extensive simulation results are illustrated to show that the expression is a good approximation of the item sojourn time.     

The BER theoretical model and properties of SiPM‐based receiver for OOK optical communication

The bit error rate (BER) theory of silicon photomultiplier (SiPM) based on‐off keying optical communication receiver, which introduces photon equivalent threshold is established. The optical crosstalk effect, the dark counts, the amplitude fluctuations of output pulses of SiPM, the baseline fluctuation, the shape of the incident light pulse, the adjacent symbol interference as well as the photon detection efficiency (PDE) are considered in the theory model. The numerical result shows that the average minimum optical power required is much smaller than that of the avalanche photodiode‐based receivers under the same conditions. The BER of SiPM‐based optical communication receiver is very sensitive to the PDE and optical crosstalk (OC) probability of SiPM. For the application of digital optical communication, a SiPM with high PDE but low OC probability and low dark count rate is a preference, under the premise that the output pulse is fast enough. For the state‐of‐the‐art SiPMs, the dark count rate is small enough to obtain adequate BER, and the OC effect is not a big limitation of the performance of SiPM‐based receiver. Moreover, the amplitude fluctuation and the baseline fluctuation of the SiPM‐based receiver are not bottlenecks of the performance in practice.     

准数字示样DRFM对线性调频脉压雷达的干扰和仿真

传统的干扰信号通过线性调频雷达脉冲压缩处理后,能量损失严重,不能很好的完成干扰的任务.本文简述了DRFM的原理、分类和优缺点,提出准数字示样DRFM的干扰方式,分析这种方式对线性调频脉压雷达干扰的有效性并对此进行仿真.