电离层遥感远紫外成像光谱仪光学系统设计

基于Czerny-Turner分光结构的成像光谱仪光学系统,介绍了一种用于电离层观测的远紫外成像光谱仪光学系统设计方法。分析了该结构的像差来源,提出了使用发散光照明光路的消像差方法,计算了像差校正条件。设计了工作在120～180nm波长范围内的远紫外成像光谱仪光学系统,视场角为6.0°×0.1°,焦距为121.8mm,F数为6.2。利用调制传递函数(MTF)和成像仿真分析的方法对该系统的主要性能参数进行了评价,验证了设计的成像光谱仪的光谱分辨力优于1.0nm,空间分辨力优于0.1°,完全满足电离层观测的应用要求。与同类设计相比,该系统不含非球面光学元件,加工装调简单且易于工程实现。     

基于极坐标变换去除计算机层析图像环形伪影

探测器像元响应的不一致、光源能不稳定等因素使得计算机层析(CT)图像中含有较多的环形伪影,严重降低了图像质量,影响了图像的三维重建和量化分析,为此提出了基于极坐标变换与傅里叶变换后低通滤波的算法去除环形伪影。通过极坐标变换将直角坐标下的环形伪影转化为极坐标下的线性伪影,然后对线性伪影图像进行傅里叶变换获得频谱图像,进而设计二维低通滤波器进行滤波处理,最后通过傅里叶逆变换与坐标逆变换获得校正后的图像。利用Matlab软件,编写程序对算法进行验证,结果表明,该算法能够有效地去除环形伪影,使图像内部细节清晰可见,并且保护了图像边缘信息,提高了图像的信噪比;另外,使用该方法处理100张切片图像只需3.5min,可满足批量处理的需求。     

Homogeneous-aligned high-transmission and fast-response liquid crystal display with three-layer electrodes

A homogeneous-aligned, high-transmission, and fast-response liquid crystal display (LCD) with three-layer electrodes is proposed. The molecules of liquid crystals are more inclined to rotate above and between the pixel electrodes. This induces a much higher transmission than that of the cell driven by the fringe field switching method and a wide viewing angle simultaneously because of the combined fringe and in-plane electric fields. Furthermore, a trigger pulse voltage is applied between the top and common electrodes to forcibly align the liquid crystal molecules vertically to show the transient dark state, which results in a very fast turn-off time (～1 ms). With high degree of transmission and fast response time, this kind of LCD is a potential candidate for large LCD panels.     

带有临界指标的非线性Poisson-Schrdinger系统解的不存在性(英文)

本文研究一个在强非线性项阻碍临界增长条件下Poisson-Schrdinger(PS)系统的孤波解.分别利用变分不等式和Pohozaev型讨论,证明了径向对称解和非平凡解的不存在性.     

例析如何在物理探究实验中培养学生的科学探究能力

以两个探究实验"对‘不透明物体只反射与它颜色相同的光’的质疑"和"在‘验证最大静摩擦力大于滑动摩擦力实验’中,如何选取连接材料"为案例,学生利用已掌握的知识和技能探究得出科学合理的实验结论.让学生在探究实验中体验科学探究能力培养的具体步骤,即提出明确的科学问题、获取实验数据、得出合理的科学结论、评估其科学意义和与他人进行学术交流.从而更好地为初高中物理实验教学培养学生科学素养提供可行性方案.     

Hydrogen Bonds Strengthened Metal-Free Perovskite for Degradable X-ray Detector with Enhanced Stability,Flexibility and Sensitivity

Metal-free perovskites (MFPs) with flexible and degradable properties have been adopted in flexible X-ray detection. For now, figuring out the key factors between structure and device performance are critical to guide the design of MFPs. Herein, MPAZE-NH₄I₃ ⋅ H₂O was first designed and synthesized with improved structural stability and device performance. Through theoretical calculations, the introducing methyl group benefits modulating tolerance factor, increases dipole moment and strengthens hydrogen bonds. Meanwhile, H₂O increases the hydrogen bond formation sites and synergistically realizes the band nature modulation, ionic migration inhibition and structural stiffness optimization. Spectra analysis also proves that the improved electron-phonon coupling and carrier recombination lifetime contribute to enhanced performance. Finally, a flexible and degradable X-ray detector was fabricated with the highest sensitivity of 740.8 μC Gy_air⁻¹ cm⁻² and low detection limit (0.14 nGy_air s⁻¹).     

金催化化学概况及新进展

金催化的有机化学反应在最近的十几年内得到巨大发展.本文从金化学的两类重要概念出发,讨论了金化学反应的本质,同时结合亲核加成和碳氢活化两个反应类型进行探讨,并分析了目前该领域的热点.     

Retracted: The Effect of Air on the Oxidation Decomposition of Cationic Exchange Resins in a Ternary Li2CO3−Na2CO3−K2CO3 Molten-Salt System

The molten-salt oxidation method (MSO) can be applied for disposal of spent cationic exchange resins (CERs) after the treatment of nuclear industry wastewater. In this work, the oxidation decomposition of resins in carbonate molten salt in N₂ and air atmospheres was investigated. The SEM morphology and FTIR spectrograms indicated that the addition of air obviously prompted the oxidation decomposition of the benzene ring, S−O bond and S−C bond in residues and the decomposition efficiency of resins reached 98.69 % at 800 °C. The XPS analysis showed the conversion of sulfur species in residues. The peroxide and superoxide ions in carbonate molten salt prompted the decomposition of thiophene sulfur and resulted in the formation of sulfate. The retention rate of sulfur in spent salt was 84.36 % at 800 °C. This work provided more theoretical guidance for the treatment of resins and technical support for the sustainable development of nuclear industry.     

Electronic Structure of [Cu(C7H4NO3S)2(H2O)4] · 2H2O Crystal

The electronic absorption spectrum and ESR spectrum of the crystal of the title compound [Cu(C₇H₄NO₃S)₂(H₂O)₄] · 2 H₂O, are measured. The experimental results are discussed quantitatively by using the ligand field theory and the radial wave function of non-free Cu(II). The electronic structure of the compound is in agreement with its crystal structure.