蓝宝石光纤法布里-珀罗高温传感的实验研究

进行了基于蓝宝石光纤及晶片的光纤法布里- 珀罗(F-P)高温传感器研究。理论仿真分析了传感器温度传感灵敏度及干涉光谱信号质量 随蓝宝石晶片厚度 变化趋势。结果表明,在信噪比(SNR)为30〖J P ＋2〗dB、晶片厚为75μm时,可避免干涉光谱信号波峰干涉级次跳 变问题, 同时获得3.114nm/℃(1080℃)的温度传感 灵敏度。建立了高温传感器系统,并基于干涉光谱相位分析算法 进行解调,实现了130～1080℃测温范围,测 温误差小于±2.45℃, 1080℃下温度传感灵敏度测试值为2. 973nm/℃,与理论温度传感灵敏度基本吻合。     

能量分析攻击及其防御策略研究

针对密码系统的旁路攻击已从时间攻击发展到更为有效的能量分析攻击阶段。本文即从两类能量分析攻击方式的原理入手,对其产生背景、技术原理、实施手段等进行了详细介绍,并在其中引入具体攻击DES算法的实例。最后,给出了针对此类攻击的防御策略。     

Strong Electronic Interaction of Amorphous Fe2O3 Nanosheets with Single‐Atom Pt toward Enhanced Carbon Monoxide Oxidation

Platinum‐based catalysts are critical to several chemical processes, but their efficiency is not satisfying enough in some cases, because only the surface active‐site atoms participate in the reaction. Henceforth, catalysts with single‐atom dispersions are highly desirable to maximize their mass efficiency, but fabricating these structures using a controllable method is still challenging. Most previous studies have focused on crystalline materials. However, amorphous materials may have enhanced performance due to their distorted and isotropic nature with numerous defects. Here reported is the facile synthesis of an atomically dispersed catalyst that consists of single Pt atoms and amorphous Fe₂O₃ nanosheets. Rational control can regulate the morphology from single atom clusters to sub‐nanoparticles. Density functional theory calculations show the synergistic effect resulted from the strong binding and stabilization of single Pt atoms with the strong metal‐support interaction between the in situ locally anchored Pt atoms and Fe₂O₃ lead to a weak CO adsorption. Moreover, the distorted amorphous Fe₂O₃ with O vacancies is beneficial for the activation of O₂, which further facilitates CO oxidation on nearby Pt sites or interface sites between Pt and Fe₂O₃, resulting in the extremely high performance for CO oxidation of the atomic catalyst.     

基于Vega的动态红外图像仿真

为提高红外图像的仿真效果,在Vega平台实现动态红外图像的仿真。首先分析了目标场景辐射特性模型、大气传输模型以及红外探测器模型,然后以F-16飞机为例详细地分析了Creator建立三维模型和在Vega平台完成动态红外图像仿真的过程,最后利用MFC和Vega API编程开发了友好的交互界面,用于不同仿真条件的切换和参数的调整。仿真实验结果表明该方法简单易行、有较高的逼真度,可为红外目标模拟器提供信号源。     

单相电压源变换器减少开关次数调制算法的研究

作为基本的电力电子变换器,单相全桥结构两电平电压源变换器包括单相电压源逆变器、单相并网逆变器、单相电压源整流器和单相有源电力滤波器,具有广泛的应用场合。鉴于单相电压源变换器具有多解性,可以寻找一种减少开关次数的调制算法,以便降低开关损耗。本文根据三相电压源全桥结构两电平电压源变换器的最小开关次数调制算法,设计了一种适合单相全桥结构两电平电压源变换器的最少开关次数的调制算法,在理论分析的基础上,采用MATLAB/SIMULINK进行了仿真验证。     

A Convenient Organic–Inorganic Hybrid Approach Toward Highly Stable Squaraine Dyes with Reduced H‐Aggregation

A generic and effective approach for solving the aggregation effect observed with optical materials in solid state or in a solution with a poor solvent was explored by designing two types of squaraine‐containing polyhedral oligomeric silsesquoixane (POSS)‐based hybrids. It is expected that incorporation of “huge” inorganic POSS nanoparticles into optical materials via covalent bonding can effectively decrease the strong dipole–dipole and π–π stacking interactions, inhibit intermolecular charge transfer between adjacent squaraine molecules, and improve optical, thermal and chemical stability of the resultant materials. Both theoretical calculations and experimental results indicate that the molecular design strategy is rational and efficacious. The resultant organic–inorganic hybrid optical materials effectively eliminate the aggregation of organic optical chromophoric groups by hindering intermolecular charge transfer and decreasing dipole–dipole and π–π stacking interaction between the chromophores, and exhibit good optical stability, i.e., the absorption peaks of H1 and H2 display only a slight blue‐shift, even in the solid. Simultaneously, the hybrids also show significantly enhanced thermal, and chemical stabilities in comparison with the precursor organic optical materials.     

基于Zernike多项式波面拟合中边界误差的影响分析

波面拟合实质上就是把携带测量表面信息的离散点采样数据拟合成与实际波面尽可能一致的数学上的波面函数;在光学检测中,由于Zernike多项式在单位圆域里具有正交性而通常被选作拟合基函数.Zemike拟合首先需要进行归一化处理,而待拟合的离散数据组的中心点和半径坐标值是归一化处理所需要的必要参数.简单介绍了基于Zemike多项式的波面拟合方法,重点分析了被拟合数据组边界误差(中心点和半径值误差)对拟合结果的影响.分析结果表明边界误差将影响到各项Zernike拟合系数精度,其影响程度与边界误差大小有关.因此,在实际的波面拟合分析中有必要采用一些有效的方法以提高待拟合数据组中心点和半径值的确定精度.     

7050航空铝合金激光冲击强化残余压应力研究

用激光冲击强化处理装置对重要航空铝合金结构材料7050T7451、7050T7452不同工艺条件下进行了冲击强化处理,并对试件激光冲击区存在的残余压应力进行了测量。结果显示经激光冲击处理后试件表面具有极高的残余压应力,可达-200MPa以上;经过两次迭加冲击处理能够极大提高强化效果,其残余压应力相比单次冲击处理提高1倍以上;单面两次迭加处理与双面依次迭加冲击处理相比,试件正面(先冲击一面)残余压应力水平相当,且双面依次迭加处理试件反面(后冲击一面)的残余压应力远小于正面。以上一系列重要结果均为首次通过试验发现,对激光冲击强化处理技术的实际工程应用具有指导性意义。最后还给出了相应的表层组织结构分析和疲劳寿命试验结果。     

三维荧光光谱技术及平行因子分析法在绿茶分析及种类鉴别中的应用

提出了一种绿茶成分分析和种类鉴别的新方法。利用FS920荧光光谱仪测量得到国内生产的26个绿茶样品的三维荧光光谱矩阵(EEMs),建立了不同种类绿茶在特定范围内(激发波长为300～550 nm,发射波长为310～750 nm)的三维荧光光谱图和等高线光谱图。采用平行因子分析法(PARAFAC)计算得到绿茶的3因子激发-发射光谱轮廓图和样品因子投影得分图。通过因子光谱特征分析确定绿茶的三种主要成分(茶多酚、黄酮醇及叶绿素);通过三维荧光光谱图和等高线光谱图的图谱特征和样品因子投影得分图的分析,证实三维荧光光谱技术和平行因子分析法对绿茶进行成分分析和种类鉴别,是一种高效、精确的方法。     

Organic Nanoprobe Cocktails for Multilocal and Multicolor Fluorescence Imaging of Reactive Oxygen Species

Hypochlorite (ClO^?) as a highly reactive oxygen species not only acts as a powerful “guarder” in innate host defense but also regulates inflammation‐related pathological conditions. Despite the availability of fluorescence probes for detection of ClO^? in cells, most of them can only detect ClO^? in single cellular organelle, limiting the capability to fully elucidate the synergistic effect of different organelles on the generation of ClO^?. This study proposes a nanoprobe cocktail approach for multicolor and multiorganelle imaging of ClO^? in cells. Two semiconducting oligomers with different π‐conjugation length are synthesized, both of which contain phenothiazine to specifically react with ClO^? but show different fluorescent color responses. These sensing components are self‐assembled into the nanoprobes with the ability to target cellular lysosome and mitochondria, respectively. The mixture of these nanoprobes forms a nano‐cocktail that allows for simultaneous imaging of elevated level of ClO^? in lysosome and mitochondria according to fluorescence color variations under selective excitation of each nanoprobe. Thus, this study provides a general concept to design probe cocktails for multilocal and multicolor imaging.