曲率限制的红外焦平面告警系统目标搜索算法

为了降低红外焦平面告警系统中较高的虚警率,提出了一种速度限制基础上基于曲率限制的目标搜索算法。以视场角5.34.0凝视型红外告警系统为例,在MATLAB中对红外图像序列进行了目标搜索实验,验证了该算法的可行性。按照蒙特卡罗法思路模拟了包含大量随机噪声的目标场景,研究了该算法相比传统多帧检测算法对随机噪声的抗干扰性。对该算法的搜索帧数进行了扩展,给出了不同搜索帧数的搜索效果和时效性表现。     

Analytical model of an acoustic diode comprising a superlattice and a nonlinear medium

We give an analytical analysis to the acoustic propagation in an acoustic diode (AD) model formed by coupling a superlattice (SL) with a nonlinear medium. Analytical solutions of the acoustic transmission are obtained by studying the propagations in the SL and the nonlinear medium separately with the conventional transfer-matrix method and a perturbation technique. Compared with the previous numerical method, the proposed approach contributes a better physical insight into the intrinsic mechanism of acoustic rectification and helps us to predict the performance of an AD within the effective rectifying bands in a simple way. This is potentially significant for the practical design and fabrication of AD devices.     

初态对光波导阵列中连续量子行走影响的研究

本文使用近邻耦合模型得到的解析解,分析了周期性波导中输入态对量子行走的粒子数的概率分布函数 和二阶相干性的影响.结果表明:输入态的对称性质对量子行走过程的二阶相干度有影响, 而对粒子数的概率分布函数影响不大. 关键词： 周期性光波导阵列 量子行走 二阶相干度 纠缠态     

Optical properties of surface-modified Bi2O3 nanoparticles

Stearic acid coated Bi₂O₃ nanoparticles in the size range of 5-13 nm were synthesized by the microemulsion method. HRTEM showed that the morphology of Bi₂O₃ nanoparticles was ellipsoidal. The absorption edge of Bi₂O₃ nanoparticles showed a blue shift of ∼0.45 eV, comparing with that of the bulk Bi₂O₃. At room temperature, Bi₂O₃ nanoparticles also showed a strong luminescence at 397 and 420 nm, depending on the excitation wavelength.     

离子速度成像技术研究2-溴戊烷的光解离动力学

运用离子速度成像技术研究了2-溴戊烷分子在～234 nm处的光解离动力学. 通过分析光解产物Br(²P_3/2)(简称Br)和Br(²P_1/2) (简称Br*)的速度影像,分别得到其速度分布和角度分布. Br和Br*的速度分布可以用两个高斯分布拟合,分别对应于2-溴戊烷在～234 nm处两个独立的光解离反应通道. 高能的高斯分量对应于C-Br伸缩振动模式的直接解离,低能的高斯分量对应于弯曲振动和C-Br伸缩振动耦合所导致的解离. 确定出光解离产物Br的相对量子产率为0.892,结合Br和Br*碎片的各项异性参数和溴原子的相对量子产率,讨论了³Q₀、³Q₁和¹Q₁激发态分别对产物Br和Br*的贡献. 通过对比溴代戊烷4种同分异构体光解离过程的差异,讨论了分子烷基分支化对光解机理的影响.     

A bubble detection technique based on light intensity and Mie scattering theory for spinning solution

A novel bubble detection technique based on light intensity and Mie scattering theory for spinning solution is presented theoretically and experimentally. With the light intensity in every direction, the particle or bubble size distribution can be calculated with the Mie scattering theory. The light intensity distribution in every direction, corresponding to the light intensity received by every assumed annulus of the detector has been calculated theoretically. According to the light intensity distribution, the size distribution of bubbles can be deduced. A series of standardized polystyrene micro-sphere (with 7 μm diameter) solution has been used not only as sample for experiments and calibration, but also as the bubbles in the glycerin. Theoretical and experimental results show that the technique can be used for bubble detection, in order to improve the traditional bubble detection scheme, and to lower production costs.     

Synthesis of Fluorescent Gold Nanoclusters Directed by Bovine Serum Albumin and Application for Nitrite Detection

In the present work, gold nanocluster (GNC) induced by bovine serum albumin (BSA) was synthesized as a novel fluorescence probe to detect nitrite (NO₂ ^?) sensitively and selectively. The fluorescence of GNC was found to be quenched effectively by NO₂ ^?. Under the optimum conditions, it was found that the change of fluorescence intensity was proportional with the concentration of NO₂ ^? in the linear range of 0.1–50 μM (R?=?0.9990), with a detection limit (S/N?=?3) of 30 nM. The absorption spectroscopy, circular dichroism (CD), and X-ray photoelectron spectroscopy (XPS) studies were employed to discuss the quenching mechanism. In addition, the present approach was successfully applied in real water samples.     

大气湍流三维波前探测模式层析算法分析

大气湍流三维波前探测是实现多层共轭自适应光学技术的关键和前提. 对湍流三维波前探测中最常用的模式法层析技术进行理论研究与分析, 提出该算法存在原理性限制, 并基于此对模式法层析技术产生误差的原因展开分析, 最后针对不同类型的模式层析重构误差给出数值仿真实验结果.分析表明, 模式层析重构中使用了Zernike分解基的一部分作为新的分解基进行波面拟合, 从而引入模式混淆和模式耦合两个方面的误差; 部分Zernike分解基不相关是避免模式混淆误差的必要条件, 模式耦合误差则无法避免. 最后结合仿真结果提出大视场探测、小区域重构的方法, 很好地抑制了模式耦合误差. 关键词： 三维波前探测 大气层析 模式法 误差分析     

Efficiency and multifractality analysis of CSI 300 based on multifractal detrending moving average algorithm

We apply the multifractal detrending moving average (MFDMA) to investigate and compare the efficiency and multifractality of 5-min high-frequency China Securities Index 300 (CSI 300). The results show that the CSI 300 market becomes closer to weak-form efficiency after the introduction of CSI 300 future. We find that the CSI 300 is featured by multifractality and there are less complexity and risk after the CSI 300 index future was introduced. With the shuffling, surrogating and removing extreme values procedures, we unveil that extreme events and fat-distribution are the main origin of multifractality. Besides, we discuss the knotting phenomena in multifractality, and find that the scaling range and the irregular fluctuations for large scales in the _Fq(s)$F_q\left(s\right)$ vs s$s$ plot can cause a knot.     

一种直接用示波器观测单变量非线性系统状态的新方法

为解决用示波器观测单变量非线性系统难的问题, 本文提出了一种45°线法, 该方法能将随时间变化的连续信号以特殊的方式转换成直角坐标上45°线上的点图, 并可用通用双踪示波器 (模拟或数字均可)直接显示出来, 从而达到直接方便地观测和分析单变量被测系统运行时的各种状态, 如周期稳定态, 局部和全局不稳定态. 文中详细阐述了该方法的机理. 同时, 研究和解决了设计实现该方法物理电路的关键问题, 即从连续变化的信号中提取出能反映系统状态的有用信号. 由于蔡氏电路是典型的非线性系统, 且能随参数的变化产生各种丰富的状态, 本文选用该电路作为被测系统进行了大量的物理实验, 实验结果证实了该方法的有效性和实用性. 关键词： 45°线法 单变量系统 系统状态 双踪示波器