红外耦合光学系统设计

红外目标模拟器由红外目标图像发生器和投影光学系统组成。该红外光学系统是一个要求与2个导引光学系统的光学技术参数相匹配的长焦距、大视场和具有像方远心光路的中红外光学系统。叙述用于红外目标模拟器的红外耦合光学系统的设计原理，提出它与导引光学系统一起可组成放大倍率M=4.5×的红外投影光学系统，并指出IR CRT产生的图像通过红外投影光学系统可成像在导引接收器上。针对给出的红外耦合光学系统的设计特点和技术要求，光学材料选取硅（Si） 锗（Ge） 硅（Si），采用简单的柯克三片式结构完成光学系统设计。设计评价结果表明，该系统的光学性能和成像质量均满足设计指标要求。     

退火工艺对ICF靶用冷轧镍膜的影响

 为了满足惯性约束聚变（ICF）和状态方程（EOS）实验以及靶装配工艺的需要,在薄膜轧制过程中间以及轧制工艺完成以后需要对镍膜进行热处理来改善其组织结构和力学性能。对多辊轧机冷轧的方法制备的厚11 mm镍膜中间退火工艺进行了研究,根据确定的合适的退火工艺退火后继续轧制得到成品镍膜厚7 mm,表面粗糙度小于50 nm,基本满足目前状态方程实验对箔膜的要求。金相显微照片表明镍膜晶粒经500 ℃保温1 h退火由轧制前的条带状变为等轴晶;镍膜硬度经500 ℃退火后由4 GPa降低到了2.3 GPa左右;XRD衍射测试表明镍膜经500 ℃以上温度退火后,高角度的衍射峰开始出现,织构得到一定程度的改善。由此可以确定镍膜合适的中间退火温度为520 ℃保温1 h。     

室内环境中脑控轮椅的路径跟踪控制

为了实现室内环境中脑控轮椅的自主导航,提出了一种简单有效的路径跟踪控制方法。给定的路径通常被表示为一系列离散点,根据这一特点,提出了分段直线路径跟踪方法,即依次跟踪由前后两个路径点构成的直线路径到达目标点。基于预瞄点技术并结合模糊算法和传统的PID控制方法设计控制器,完成各分段直线路径的跟踪,并给出了有效的切换条件。实验结果表明,本文提出的路径跟踪控制方法能够使脑控轮椅在室内环境中精确地跟踪给定路径。     

Differentiating bulk nanobubbles from nanodroplets and nanoparticles

History has shown that it is not as easy as one might think to differentiate between bulk nanobubbles and nanodroplets or nanoparticles. It is generally easy to detect colloids (i.e. something that looks different, e.g. scatters light differently than its surrounding solvent), but less easy to determine the nature of these colloids. This has led to misinterpretations in the literature, where nanodroplets or nanoparticles have mistakenly been assumed to be nanobubbles. In this paper, we review a multitude of experimental methods and approaches to prove the existence of bulk nanobubbles. We conclude that combinations of optical detection with physical perturbations such as pressure or ultrasound, or phase-sensitive holographic methods are the most promising and convenient approaches.     

地面目标雷达与红外特性数据库构建

为了对地面目标雷达与红外特性测试的各类数据进行统一规范化管理,使其高效应用,分析各类数据的特性及其处理方式,构建了目标特性数据库管理系统;数据库的整体设计中,在数据头和数据文件方案基础上增加了自动跟随数据表编号的路径生成方法,结合了接口式的运作结构,模块化的数据库功能和层次化的数据表结构设计思路;数据库的编制基于Access数据库管理软件和VC++编程软件,通过ADO数据库访问技术加以实现,详细描述了ADO接口的编程步骤,并对本接口不同指针的入库频率和提取效率进行了对比择优;在运行中,提出了主、副数据库移植性管理方法;工作实践验证了目标特性数据库管理系统的可靠性和高效性,为地面目标特性的测试与分析提供了良好的数据支撑。     

Scale-space point spread function based framework to boost infrared target detection algorithms

Small target detection is one of the major concern in the development of infrared surveillance systems. Detection algorithms based on Gaussian target modeling have attracted most attention from researchers in this field. However, the lack of accurate target modeling limits the performance of this type of infrared small target detection algorithms. In this paper, signal to clutter ratio (SCR) improvement mechanism based on the matched filter is described in detail and effect of Point Spread Function (PSF) on the intensity and spatial distribution of the target pixels is clarified comprehensively. In the following, a new parametric model for small infrared targets is developed based on the PSF of imaging system which can be considered as a matched filter. Based on this model, a new framework to boost model-based infrared target detection algorithms is presented. In order to show the performance of this new framework, the proposed model is adopted in Laplacian scale-space algorithms which is a well-known algorithm in the small infrared target detection field. Simulation results show that the proposed framework has better detection performance in comparison with the Gaussian one and improves the overall performance of IRST system. By analyzing the performance of the proposed algorithm based on this new framework in a quantitative manner, this new framework shows at least 20% improvement in the output SCR values in comparison with Laplacian of Gaussian (LoG) algorithm.     

一种改进的三帧差分运动目标实时检测算法

针对传统的三帧差分法提取的运动目标存在大量的噪声和空洞,提出了一种改进的三帧差分运动目标实时检测算法。该算法采用Surendra背景提取算法提取有效背景,对视频流中连续的三帧图像分别进行背景减除,得到的结果作为反馈对背景进行选择性更新,利用HSV颜色空间去除阴影后进行三帧差分,将差分结果进行“与”运行,通过将中间帧背景减除结果与“与”运算的结果进行“或”运算,这样可以得到运动目标的完整信息。实验结果表明,该算法能够快速、完整、准确地检测出运动目标,可有效应用于实时监控系统。     

黑腔冷冻靶传热与自然对流的数值模拟研究

惯性约束聚变的设计要求在靶丸内形成均匀光滑的氘氚冰层, 靶丸周围的热环境对冰层的质量特别是低阶粗糙度有很大的影响. 本文对自主研发的黑腔冷冻靶实验装置中的热物理问题展开了数值模拟, 重点考察了黑腔冷冻靶的传热和流体力学特性. 通过参数分析得到了自然对流对靶丸温度均匀性产生影响的临界条件. 比较了黑腔不同布置朝向时的流场和温度分布, 结果显示黑腔水平布置时自然对流更加强烈, 造成的靶丸温度不均匀性也更大. 在此基础上, 讨论了消除自然对流影响的可能性, 结果发现仅当黑腔垂直布置时利用黑腔分区方法能够消除对流效应对靶丸温度不均匀性的影响而黑腔水平布置时不能消除. 研究结论对于实验中冷冻靶结构的设计、改进和实验的开展等具有指导意义.     

COMPUTATION OF DILUTE PARTICULATE LAMINAR FLOW OVER A BACKWARD-FACING STEP

Particle-laden flows are calculated for a classical laminar backward- facing step problem. The particle tracks are calculated using a recently developed exponential Lagrangian tracking scheme. The behaviour of the particle-laden flow is considered for various inlet for Reynolds number, Stokes numbers and void fractions. Doping the flow with low-Stokes-number particles has the effect of increasing the inlet inertia of the flow and this increases the strength of the recirculation behind the step. High-Stokes- number particles are dominated by gravitational effects which affect the flow accordingly. Differences between the single-phase flow and the particle-laden flows are therefore dependent on the Stokes number and increase linearly with void fraction.     

灰度人脸识别形态学相关的一般理论研究

提出一般形态学相关概念,并提出一种小型联合变换相关器的硬件设计以实现一般形态学相关.提出两种改进的一般形态学相关算法,灰度图像按某种分解方法分解成一系列二值图像片.在第一种算法中,每片二值联合图像片的边缘被检测,其功率谱求和.在第二种算法中,一种情况是每片的联合变换功率谱被二值化或细化再求和;另一种情况是这些片的联合变换功率谱的总和被二值化或细化.计算机模拟结果表明,改进后的算法能改善高相似度灰度人脸图像识别的鉴别率.