25 GHz interleavers made by Michelson interferometer with a Gires–Tournois etalon

We report a high-quality interleaver with frequency spacing of 25 GHz, which is made by a Michelson interferometer with a mirror replaced by a Gires–Tournois etalon. Our optimal design and elaborate manufacture assure its excellent performance. We present the analysis of performance parameters, design of structural parameters, the unique fabrication technology and testing results of this interleaver in this paper.     

Magnetic M<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript>@N-C as heterogeneous catalysts for the catalytic oxidation of aniline solution with sulfate radicals

Metal nanoparticles have been combined with magnet metal–organic frameworks (MOFs) to afford new materials that demonstrate an efficient catalytic degradation, high stability, and excellent reusability in areas of catalysis because of their exceptionally high surface areas and structural diversity. Magnetic M _x O _y @N-C (M = Fe, Co, Mn) nanocrystals were formed on nitrogen-doped carbon surface by using 8-hydroxyquinoline as a C/N precursor. The Co@N-C, MnO@N-C, and Fe/Fe₂O₃@N-C catalysts were characterized by X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), N₂ adsorption/desorption, and X-ray photoelectron spectroscopy (XPS). The catalytic performances of catalysts were thoroughly investigated in the oxidation of aniline solution based on sulfate radicals (SO₄ ^?.) toward Fenton-like reaction. Magnetic M _x O _y @N-C exhibits an unexpectedly high catalytic activity in the degradation of aniline in water. A high magnetic M _x O _y @N-C catalytic activity was observed after the evaluation by aniline degradation in water. Aniline degradation was found to follow the first-order kinetics, and as a result, various metals significantly affected the structures and performances of the catalysts, and their catalytic activity followed the order of Co > Mn > Fe. The nanoparticles displayed good magnetic separation under the magnetic field.

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机载腔增强吸收光谱系统应用于大气NO_2空间高时间分辨率测量

介绍了一套用于机载平台测量的非相干宽带腔增强吸收光谱(IBBCEAS)系统,并应用于实际大气NO_2空间分布的高时间分辨率观测.为满足机载测量中对时间分辨率的需求,系统采用离轴抛物面镜代替消色差透镜提高光学耦合效率;并运用Allan方差,对系统性能进行了分析.通过腔增强吸收光谱系统与长光程吸收光谱系统对实际大气NO_2的对比测试,两者线性相关系数R~2达到0.86.将IBBCEAS系统应用于机载平台,在时间分辨率为2 s的情况下,探测限达到95 ppt(1σ).通过机载观测,获得了华北地区石家庄等地上空对流层大气NO_2的廓线信息.     

新型干涉高光谱成像系统的光束剪切特性分析

提出了一种基于新型双折射横向剪切分束器的高光谱成像方法,采用的横向剪切分束器主要由Wollaston棱镜和角锥反射体组成.在分析双折射分束器的偏光结构和分光机理的基础上,利用光线追迹方法分析了光束在Wollaston棱镜中的传播特性,通过计算光束在双折射分束器中的传播方向及出射位置,推导出调制光程差的理论表达公式.根据理论推导结果,分别仿真分析了系统在不同扫描模式下光程差与入射光视场角以及角锥顶点偏移量的调制关系.基于理论分析结果搭建了实验装置,对光程差分析结果进行验证,实验结果与理论分析结果匹配较好.所提方法可以提高剪切光束的平行性,保证干涉条纹的高调制度,降低了复原光谱准确度对光学装调精度和元件加工精度的依赖性,具有结构稳定、复杂度低的显著特点.     

Br_2分子在360—610 nm的光解离动力学研究

利用包含转动自由度在内的含时薛定谔方程研究了Br_2分子在波长范围为360—610 nm的光解离动力学.通过计算得到了Br_2分子在四个特征波长处的切片解离影像,并经过分析得到了与切片解离影像相对应的动能分布;计算了Br_2分子在波长范围为360—610 nm内总的动能分布,以及从A,B和C三个电子态解离的碎片各自所对应的动能分布;计算了A,B和C三个电子态各自的解离概率以及碎片产物的分支比Γ(Br~*/(Br+Br~*))随波长的变化.     

New achievements from CE-3 mission

正The Chang'E-3(CE-3)mission began with a smooth countdown and flawless launch on the Long March 3B rocket from the Xichang satellite launch center at 01:30 CST on December 2,2013.It landed on the northeastern Imbrium basin(340.49°E,44.12°N)at 21:11 CST on December 14,2013,and the Yutu rover was deployed from the lander the next morning at 04:35.The lander was equipped with a number of remote-sensing     

Ionic liquid-based electrolyte with dual-functional LiDFOB additive toward high-performance LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> batteries

Manganese oxide-based cathodes are one of the most promising lithium-ion battery (LIB) cathode materials due to their cost-effectiveness, high discharge voltage plateau (above 4.0 V vs. Li/Li⁺), superior rate capability, and environmental benignity. However, these batteries using conventional LiPF₆-based electrolytes suffer from Mn dissolution and poor cyclic capability at elevated temperature. In this paper, the ionic liquid (IL)-based electrolytes, consisting of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfon)imidate (PYR_1,4-TFSI), propylene carbonate (PC), lithium bis(trifluoromethanesulfon)imide (LiTFSI), and lithium oxalyldifluoroborate (LiDFOB) additive, were explored for improving the high temperature performance of the LiMn₂O₄ batteries. It was demonstrated that LiTFSI-ILs/PC electrolyte associated with LiDFOB addition possessed less Mn dissolution and Al corrosion at the elevated temperature in LiMn₂O₄/Li batteries. Cyclic voltammetry and electrochemical impedance spectroscopy implied that this kind of electrolyte also contributed to the formation of a highly stable solid electrolyte interface (SEI), which was in accordance with the polarization measurement and the Li deposition morphology of the symmetric lithium metal cell, thus beneficial for improving the cycling performance of the LiMn₂O₄ batteries at the elevated temperature. Cyclic voltammetry and electrochemical impedance spectroscopy implied that the cells using this kind of electrolyte exhibited better interfacial stability, which was further verified by the polarization measurement and the Li deposition morphology of the symmetric lithium metal cell, thus beneficial for improving the cycling performance of the LiMn₂O₄ batteries at the elevated temperature. These unique characteristics would endow this kind of electrolyte a very promising candidate for the manganese oxide-based batteries.     

Synthesis of hierarchical Na<Subscript>2</Subscript>FeP<Subscript>2</Subscript>O<Subscript>7</Subscript> spheres with high electrochemical performance via spray drying

Hierarchical Na₂FeP₂O₇ spheres with nanoparticles were successfully fabricated by a facile spray drying method. A relatively low drying temperature was introduced in order to form a carbon layer on the surface. As a cathode material for sodium-ion batteries, it delivered a reversible capacity of 84.4 mAh g^?1 at 0.1 C and showed excellent cycling and rate performance (64.7 mAh g^?1 at 5 C). Furthermore, a full sodium battery was fabricated using SP-Na₂FeP₂O₇ as the cathode and hard carbon as the anode, suffering almost no capacity loss after 400 cycles at 1 C. Due to its superior electrochemical property and the low materials cost, Na₂FeP₂O₇ is becoming a promising cathode material for large-scale energy storage systems.     

Mössbauer study of fired Lishan clay and terra-cotta warriors and horses of Qin dynasty (221 B.C.)

The sherds of terra-cotta warriors and horses and Lishan clay were characterized by Mossbauer spectroscopy, XRD, XRF, NAA, thermal and chemical analyses. Lishan clay was testified as the original material of terracotta warriors and horses, the kilning of these warriors and horses was first carried out in an oxidizing atmosphere, and then changed to a predominantly reducing atmosphere. With refiring experiments, the temperatures of Q3 and Q4 samples were determined to be 830±50 and 980±50°C respectively. Transformations of Lishan clay were determined by firing in oxidizing and reducing atmospheres. The Mossbauer parameters of Lishan clay, which was taken after 2–24h firing, were changing up to 12h.