Natural color low-level-light EBAPS imaging system based on three-color LCTF北大核心CSCD

The high-sensitivity electron bombarded active pixel sensor (EBAPS) not only has the characteristics of high gain and high sensitivity of vacuum imaging devices, but also has the digital characteristics of solid-state imaging devices, which greatly improves the level of night vision imaging. A natural color low-level-light EBAPS imaging system was built based on three-color liquid crystal tunable filter (LCTF). According to the characteristics of low-level-light images, the color enhancement processing such as grayscale stretching, white balance, and color correction was performed on the color images obtained by the system. The experimental results show that the system can realize the natural low-illumination color imaging that reflects the color characteristics of the scene itself, which can effectively improve the observation effect of the characteristics of the target scene at night, and can realize the color imaging under 5×10−4 lx illumination. © 2022 Editorial office of Journal of Applied Optics. All rights reserved.     

Controlled growth and field emission of vertically aligned AlN nanostructures with different morphologies

The controllable growth of three different morphologies of AlN nanostructures (nanorod, nanotip and nanocrater) arrays are successfully realized by using chemical vapour deposition (CVD) technology. All three nanostructures are of single crystal h-AlN with a growth orientation of [001]. Their growth is attributed to the vapour-liquid-solid (VLS) mechanism. To investigate the factors affecting field emission (FE) properties of AlN nanostructures, we compare their FE behaviours in several aspects. Experimental results show that AlN nanocrater arrays possess the best FE properties, such as a threshold field of 7.2~V/μm and an emission current fluctuation lower than 4%. Moreover, the three AlN nanostructures all have good field emission properties compared with a number of other excellent cathode nanomaterials, which suggests that they are future promising FE nanomaterials.     

炉内两相流动和煤粉燃烧的双流体-轨道模型

本文首次用双流体一轨道（连续介质－轨道ＣＴ）模型对大尺寸四角喷燃炉内气粒两相流动及煤粉燃烧进行了模拟。该模型基于欧拉气相方程组、欧拉颗粒连续方程和动量方程以及拉氏颗粒能量和质量变化的方程,对各子模型用ｋ－ε－ｋｐ两相湍流模型,ＥＢＵ－Ａｒｒｈｅｎｉｕｓ湍流燃烧模型,煤粉颗粒的水分蒸发,热解挥发和焦炭燃烧的扩散－动力模型,ＤＯ（离散坐标）辐射模型。采用了将坐标扭转一定角度的方法减小入口射流和网格斜交造成的伪扩散。编制了ＬＥＡＧＡＰ－ＦＵＲＮＡＣＥ－３程序,分别对冷态模型炉内两相流动和大尺寸炉内三维两相流动和煤粉燃烧进行了模拟,并与颗粒轨道（ＳＴ）模型的模拟结果进行了对照。采用ＰＤＰＡ对冷态模型炉内气粒两相流场进行了测量。冷态两相流动的模拟与实验结果的对比表明ＣＴ模型的模拟结果和实验符合较好,ＳＴ模型所得颗粒浓度分布和实验山入较大。热态模拟的结果给出了两相速度,气相温度,组分浓度和壁面热流分布。模拟结果定性合理。模拟结果显示在出口处由于气流旋转,有一局部高温区存在。     

网络计划编制系统中网络图的自动生成

本文从设计角度，系统地介绍了一个计算机网络计划编制系统中如何实现计算机辅助生成网络图和时间坐标网络图的方法与步骤。并阐述了资源优化的计算机实现。     

钪(Ⅲ)-镧系元素共显色效应的研究

显色反应中的共显色效应不仅有理论上的研究意义,而且有可能用以提高反应的灵敏度和选择性。我们首次发现,钪(Ⅲ)和镧(Ⅲ)、钇(Ⅲ)、钕(Ⅲ)、钐(Ⅲ)等与铬天青S(CAS)在较高浓度的阳离子表面活性剂溴化十四烷基三甲铵(TTAB)存在下,有很强的共显色效应。本文研究了该体系共显色效应发生的条件,制定了氧化镧中微量钪的分光光度测定方法。     

柱层析-紫外分光光度法测定糠叉丙酮含量

糠叉丙酮[1,5-bis(5-nitro-2-furyl)-3-pen-tadienone](PEN)是合成多种抗菌剂及饲料添加剂的原料。其结构式如下:     

立足基础 着眼能力 锐意创新——2007年重庆高考物理试题简析及其启示

编辑按:高考物理试卷正在部分省(市)施行自主命题,这样做有利于体现地方特色,有利于促进当地高校与中学之间的联系,2007年重庆物理试卷加强了基础知识之间的联系和综合,应该说对基础知识的教学和能力的培养有促进作用,但是难度偏高,区分度偏低,高考命题怎样处理既突出能力测试,又控制难度和区分度,又怎样设计难度较大试题的分值,这是个值得研究的重要问题,欢迎大家发表意见.     

基于高非线性光纤中四波混频饱和效应的NRZ-DPSK和RZ-DPSK信号幅度再生实验(英文)

利用高非线性光纤中的四波混频饱和效应,实验展示了42.8Gbit/s非归零差分相移键控(NRZ-DPSK)信号和归零差分相移键控(RZ-DPSK)信号的全光幅度再生.测量了NRZ-DPSK信号和RZ-DPSK信号经过高非线性光纤的功率传递曲线.在平均输入功率均为16dBm的条件下,对两种调制格式的再生性能进行了比较.实验结果显示RZ-DPSK信号具有更好的幅度再生性能.     

等温热重法测量熔融织构YBCO准单晶的化学扩散系数

用熔融织构YBCO块体研磨出来的细粉 ,筛选后可得粒度均匀的片状单晶 .单晶粒平均半径R =2 7.2 μm ,片的两个面为ab底平面 ,所以是不透氧的封闭面 ,因此可将粉视为平均半径R=2 7.2 μm的无限长圆柱体 ,以此几何模型来解二维扩散方程 .在热天平上做出恒温增重曲线 .以二维扩散方程的解来拟合增重曲线 ,得出化学扩散系数D ,和Rothman等单晶和多晶的同位素扩散系数D ab相同 .求得的热力学因子为F =10 ,和Kaupel等的结果相符 .     

伽玛函数与一个力学问题的解析解

本文借助质心系动能定理、质心运动定理和伽玛函数Γ(a)的性质,不用计算机和数学软件,得出一个力学问题的解析解.