This study investigates the self-focusing characteristics of a rectangular Airy vortex beam (RAVB) via phase modulation. Numerical simulations are conducted to examine the influence of modulation parameters, including linear factor (c), topological charge (l) and wavelength (λ) on RAVB self-focusing characteristics. The focus depth, focus spot size and peak intensity of RAVB can be effectively controlled via the modulation parameters. Among these parameters, c has the most significant impact on RAVB self-focusing characteristics. As c increases from 4 to 8, the focus depth changes from 8 cm to 41 cm, while the peak intensity increases to 50 times. Although variations in l and λ also contribute to increases in both focus depth and peak intensity, their effects are relatively minor compared to those of c.

针对现有的彩色全息技术中存在的制作过程复杂、色串扰、技术条件要求高等问题,提出了 一种计算机制一步彩色彩虹全息技术.该技术将光学一步法彩虹全息技术和多次曝光彩色全息技术相结合,首先根据线全息图理论,确定每个物点的线全息图在整个彩虹全息图中的区域范围,并计算线全息图,然后将每个物点的线全息图相加,直接获得计算机制一步彩虹全息图,大大减少了全息图的计算量.在此基础上,分别计算彩色物体的红、绿、蓝三分色计算全息图,并合成为彩色彩虹全息图,用白光再现获得真彩色全息再现像,大大简化了彩色彩虹全息图的制作过程、降低了技术条件要求,充分发挥了计算全息简单、灵活、方便的优点.给出了理论分析和实验结果.

为了获取高质量的彩色动态全息,采用计算机编码的方法,提出了一种制彩色动态全息的新方法.根据色度学和采样原理,将任一分动作物点分解为红、绿、蓝三基色物点,计算编码调整三基色物点的位置,使它们对应的含体视对的3张分色全息图放置在同一平面上,经共轭光再现后,所有体视对的再现像能在空间上完全重合,并记录重合像与参考光干涉后的彩色全息图.结果表明,彩色全息图经再现后,随着人眼位置的移动,可见不同的动作像,从而实现彩色动态效果.此方法能有效解决彩色动态全息图再现像难重合、对实验条件要求高的问题;且操作简单易行,能有效避免一些不必要的噪声,在3维显示方面具有较好的应用价值.

信息化教学是近些年来教育改革的重心和热点.结合省虚拟仿真实验示范中心和省在线精品课程的建设经验以及此次疫情的实践教学经验,对信息化实践教学模式的必要性、整体目标与框架、建设内容和成效展开了讨论.提出了一种虚实结合、网络教学与线下实践相融的大学物理实验教学模式.此教学模式有利于增强学生的学习兴趣和实践创新能力,提高实验教学质量和学生学习效率,对实验教学研究有一定的参考价值.

Fast radio bursts (FRBs) are intense radio pulses with millisecond-duration from the sky, the physical origin of which remains a mystery. A compact binary model consisting of a magnetic white dwarf and a neutron star with strong bipolar magnetic field may be responsible for the central engine of repeating FRBs. The scenario is that, when the white dwarf fills its Roche lobe, mass transfer will occur through the inner Lagrange point, and the white dwarf may be kicked away after a mass transfer process. For the only known repeating burst source, i.e., FRB 121102, 41 repeating events have been detected. With the known redshift and the 41 repeating bursts, we revisit the neutron star-white dwarf binary model and confirm that such an intermittent Roche-lobe overflow mechanism can be responsible for the observed repeating behavior of FRB 121102. In addition, no correlation exists between the time interval of two adjacent bursts and the fluence of the subsequent burst, which agrees with the Roche-lobe overflow mechanism.

对高职模拟电子技术实训课程"音频功率放大器制作"进行了教学实践探索, 详细论述了实训电路组成及工作原理, 阐述了基于项目驱动的实训课程教学过程, 提出了课程的评价考核方式, 总结了实训中存在的常见问题并提出了相应对策.

In view of the problems existing in the traditional college physics experiment teaching,this paper puts forward a teaching mode of physics experiment in college classroom based on " micro-lecture".This teaching model is divided into three aspects,i.e.,video learning + preview test;experimental operation + group discussion;experimental report + innovation experiment.The students who are interested and capable have been added open laboratories to expand their experiments and design experiments.This teaching model can urge students to complete online preview,ensure students adequate classroom operation time,consolidate learnt knowledge after-school effectively.And open laboratory provides students a platform for improvement and innovation.So the model not only ensures a good teaching effect,but also improves students awareness of self-learning and trains their innovative ability.

Different from the pseudo three-dimensional (3D) visualization of computer tomography (CT)images synthesized by computer softwares,a new technology of 3D visualization of color CT images based on computer generated holography is proposed.A set of color CT images are decomposed into three primary color CT images of red,green and blue,then,the two-dimension information of this set of color CT images is synthesized into 3D information using three computer generated holograms (CGHs)which are saved in a computer.Because all CT images are two-dimension,fast-Fourier-transform algorithm that can greatly speed up the calculation of CGHs is adopted.3D photoelectric display system of color CT images is set up,in which,three CGHs are displayed on three liquid crystal spatial light modulators (LC-SLM) cormected to a computer.Re-illuminating the three CGHs with red,green and blue laser simultaneously,three 3D monochrome CT images of three primary colors are obtained,and a 3D color CT image is gotten by fusing the three 3D monochrome CT images together with X-Cube.A fog screen is used in this system as the 3D display screen for the final 3D color CT image,that not only increases the visual angle,but also enhances the stereoscopic effects of the 3D color CT image.The principle and experimental result are given.

针对分光计调整难度大、耗费时间长等问题,在分析分光计的调节原理和调节难点的基础上,针对通过望远镜目镜能否看到反射的十字叉丝像的三种不同情况,分别探讨了分光计的调节方法和技巧.

This study proposes a method to create a dynamic color hologram by using the coding method. According to the colorimetric principle, a color object can be resolved into three primary color objects. Thus, when we create a dynamic color hologram, we can regard every object as three primary color objects once we obtain the color and three-dimensional coordinate data of the objects. Coordinate data concerning the behavior of the three primary color objects are coded by the relationship between the objects and their hologram images. Therefore, when the three monochromatic holograms are calculated on a plane, they reappear due to conjugate light, and overlap at points in the plane where the color object had been located. Three line-monochromatic Fresnel holograms with stereoscopic image pairs are then computed according to the theory of light propagation and the relationship between object and image. The overlapping images experience interference due to the reference light to form a dynamic color hologram. Experiments showed that the proposed method can simplify the creation of high-quality dynamic color histograms.

选取2005年1月-2016年12月期间具有X射线余辉观测的16个γ射线暴的短暴数据样本,估算史瓦西黑洞外中微子主导吸积盘的质量,发现大部分盘的质量远大于模拟的最大值.这个结果表明,短暴要求更大质量的吸积盘,即史瓦西黑洞的吸积不足以提供多数短暴能量,短暴爆发所需要的能量可能需要黑洞的自旋或其他的电磁动力学过程来提供.

选取Swift卫星从2005年5月-2015年4月间观测的具有显著X射线耀发的已知红移的γ射线暴,共200个X射线耀发,分析γ暴本身的各向同性能Eγ,iso和晚期每个X射线耀发0.3～10 keY波段的各向同性能Ex.iso,比较它们的演化.研究发现:Eγ,iso和Ex,iso的分布没有显著区别,并且都满足高斯分布,但是Eγ,iso比Ex,iso高两个数量级.对γ暴本身和X射线耀发平均流量分布的统计结果显示,γ暴本身的流量也比X射线耀发高两个数量级.说明X射线耀发可能是中心引擎在晚期的活动产生的,但是中心引擎的活动在后期不断衰减,引起总的能量在降低.

Based on the colorimetric principle,a color object can be coded into a red object,a green object and a blue object.So,the color object can be coded into three primary color objects in making color rainbow hologram.The coordinates of three primary color objects can be calculated according to the relationship between the objects and their holograms,then the diffraction wave from three primary color objects in the hologram plane can be calculated,which is interfered through a reference light to form a hologram.After the hologram is shown by SLM and is illuminated by the light with continuous spectrum,three primary color images will superposite in space to form a color image.This method use a equivalent hologram instead of three monochrome holograms,which provide a simple and convenient way to make a high-quality color hologram.

Different with the fact that the traditional imaging optics emphasizes its ability to get clear image on the image plane, the purpose of LED illumination design is to meet the requirement of high availability of optical energy and homogeneity of illumination. As the study object, the LED track lighting has been designed with secondary optical design by the Lighttools design software. After using TIR lens which has two ways of concentrating: reflectors and lenses, the exit light of the spotlight will be adjusted and the illuminated surface will be with high homogeneity. Therefore, it will reduce the harm of the light to human's eyes. In this study, the LED spotlights have been produced and tested with the corresponding test results: Lighting power is 7W, luminous efficiency is82.57lm/W, color rendering index is 83.7, the main wavelength is 488.2nm, the ratio of red, green, blue is 13.1: 83.0: 3.9.

基于色度学原理和全息图的基本物像关系,提出利用等效编码法制作彩色彩虹全息图.首先,将空间坐标确定的彩色物点,编码为三个不同空间坐标的三基色等效物点,它们的空间坐标由全息物像关系确定.在一全息记录面上的不同位置,计算出三基色物点对应的三条线全息图.然后,利用平面共轭光再现三线全息图,在原彩色物点位置能看到完全重合的三分色全息图再现像,重合像与参考光干涉后,获得彩色全息图.经实验验证,此方法有效解决了两步法制彩色全息图时,三分色全息处于同一平面再现时,它们的再现像无法重合的问题.

Based on analyzing the relationship among the hologram spatial frequency, the object size and the hologram record distance in making the color hologram by two-step method,a method for making color hologram of large objects was proposed.Firstly, the tricolor hologram H1rgb was recorded in visual plane after intercalating right parameters, so as to make sure the full information were recorded in the least area and when H1rgb placed in the same plane, their reappeared images could overlap.Then, the overlapped images were recorded to acquire the color hologram after the information of objects were enlarged by the conjugate light.This method can enlarge the field of view(FOV) and sit for making hologram of large objects.It is verified by experiment that the FOV can be widen by 6 times.

基于Whittaker-Shannon抽样定理,对计算全息的采样进行了研究,获取适合计算全息图的采样间隔,并研究了菲涅尔全息图采样间隔与全息图尺寸、物点坐标及物点到全息面距离的关系以及傅里叶变换全息中全息面记录点数与物点采样间隔的关系.实验模拟表明此方法采样后的全息图再现像效果较好,且有利于减少全息图的信息存储量和提高全息图的计算速度.