External optical feedback effects in a frequency locking dual frequency laser

We present a systematic study of external optical feedback effects on the output characteristics of the two orthogonally polarized modes in a frequency locking dual frequency laser. Accompanied by the change of the external cavity length, the length of the resonance cavity is changed very slowly to set the oscillating modes sweeping across the laser gain curve. Comprehensive results are obtained and a strong mode competition is observed. Particularly, when the laser runs in the middle region of the gain curve, which mode can oscillate is determined by the movement direction of the external feedback mirror. Based on the phenomenon, a displacement sensor with directional discrimination is proposed and its capability is also discussed.     

Uncertainty Analysis in Triangle Orientation Discrimination Threshold Measurement

The Triangle Orientation Discrimination Threshold (TOD) is a new figure of merit for characterizing the performance of an infrared imager. In this paper, focusing on a reflective infrared target projector, the TOD curve is measured utilizing four alternative forced choice (4AFC) test method. Furthermore, the dominant sources affecting uncertainties in the TOD measure values, are analyzed in detail, the effective temperature difference, sensor, and observer. And, the variation of the TOD measurement is described quantitatively utilizing the uncertainty analysis theory. Simulation results show that the TOD measurement values vary in a small range, which show a higher stability than minimum resolvable temperature difference (MRTD) measure values. Project supported by National natural foundation of China (No: 60477038).     

Intracellular Entropy-Driven Multi-Bit DNA Computing for Tumor Progression Discrimination

Tumor progressions such as metastasis are complicated events that involve abnormal expression of different miRNAs and enzymes. Monitoring these biomolecules in live cells with computational DNA nanotechnology may enable discrimination of tumor progression via digital outputs. Herein, we report intracellular entropy-driven multivalent DNA circuits to implement multi-bit computing for simultaneous analysis of intracellular telomerase and microRNAs including miR-21 and miR-31. These three biomolecules can trigger respective DNA strand displacement recycling reactions for signal amplification. They are visualized by fluorescence imaging, and their signal outputs are encoded as multi-bit binary codes for different cell types. The results can discriminate non-tumorigenic, malignant and metastatic breast cells as well as respective tumors. This DNA computing circuit is further performed in a microfluidic chip to differentiate rare co-cultured cells, which holds a potential for the analysis of clinical samples.     

大口径光学元件表面灰尘与麻点自动判别

在大口径光学元件表面疵病初检时,灰尘和麻点由于形态类似,不易区分。针对该问题,提出了一种基于模式识别理论的灰尘麻点判别方法。该判别方法以既有的疵病检测系统为基础,根据灰尘麻点的暗场成像特点,选取了合适的特征并根据因子分析理论对特征进行变换,最后基于贝叶斯判别原理对灰尘麻点进行分类。采用自制定标板建立了灰尘麻点训练样本库,并进行多组实验,选取了合适的判别函数,最后进行了对未知样品表面灰尘麻点的区分。实验结果表明,该判别方法的正确率可以达到95%以上。目前此判别方法已经用于惯性约束聚变系统中大口径光学元件表面灰尘与麻点自动区分。     

高能X射线基材料分解法基材料选择方法

选择基材料是高能双能X射线基材料分解法的重要环节。为了解基材料对材料识别精度的影响,确定选择基材料的方法和原则,利用美国国家标准与技术研究院(NIST)给出的材料的线性衰减系数,选择不同基材料,分析计算了各种待检测材料的原子序数和电子密度及相对误差。归纳总结出选取基材料的"临近原则",即基材料与待检测材料的原子序数接近,能提高待检测材料原子序数和电子密度的分解计算精度。在此基础上,提出了四能基材料分解法。理论计算表明四能基材料分解法比双能基材料分解法对多种材料的整体识别精度更高,更适合用于多种材料同时存在情况下的识别与检测。运用蒙特卡罗方法模拟验证了四能基材料分解法用于实际的可行性。     

A study of hadronic shower development in the ECAL of the alpha magnetic spectrometer Ⅱ

In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e^±-π^± discrimination and tau jet reconstruction was discussed.     

Timing properties and pulse shape discrimination of LAB-based liquid scintillator

Linear Alkyl Benzene (LAB) is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied through ultraviolet and ionization excitation in this study. The decay time of LAB, PPO and bis-MSB is found to be 48.6 ns, 1.55 ns and 1.5 ns, respectively. A model can describe the absorption and re-emission process between PPO and bis-MSB perfectly. The energy transfer time between LAB and PPO with different concentrations can be obtained via another model. We also show that the LAB-based liquid scintillator has good (n, γ) and (α, γ) discrimination power.     

基于FISS成像光谱数据牛奶品种识别研究

利用自主研制的地面成像光谱辐射测量系统(field imaging spectrometer system,FISS)获取了14种典型牛奶样品的高光谱图像数据,并基于此做了牛奶品种识别研究.首先剔除2个异常样品,对剩余12种牛奶样品随机取样,共取1 200个像元样本;为消除高频随机噪声和基线偏移,改善多重共线性,对所有...     

调制无线电信号的分形特征研究

调制方式的不同以及信号受到功率放大器的非线性变换决定了调制无线电信号的形状存在着差异,提取这些差异特征是信号识别的基础. 基于分形理论提取信号特征是一种新的方法,本文模拟了在不同信噪比条件下,通过计算调制无线电信号的方差分形维以及Mandelbrot奇异分形维谱,将信号的调制特征以及非线性变换特征投射到分形特征空间. 数值仿真结果表明,不同调制方式、非线性变换对应了分形特征空间中的不同位置. 这些结果表明分形理论能够有效提取无线电信号的调制特征以及功率放大器的特征,对信号的调制方式以及个体特征识别具有一定 关键词： 无线电 信号 分形特征 识别     

ICP-MS混合模式测定植物性农产品中的9种痕量元素

建立了ICP- MS混合模式测定蔬菜、水果、大米等植物性农产品中痕量元素的检测方法.样品经HNO3 + H2O2消解,以74Ge,115In、209Bi作为内标溶液消除基体干扰,动能歧视型碰撞/反应池技术消除质谱干扰的方式测定植物性农产品中As,Hg,Pb,Cd,Cr,Se,Cu,Ni,Zn 9种痕量元素.结果表明:该...