Investigation of multilayer microstrip electrode for an asymmetric Mach–Zehnder modulator

In the condition of velocity matching and impedance matching, Mach–Zehnder modulator can obtain large bandwidth and low driving voltage. Based on Wheeler’s transformation of multilayer microstrip line, effective permittivity of microwave has been analyzed. Both the microwave index and characteristic impedance are affected by the thickness and the width of microstrip electrode. In order to achieve velocity matching and impedance matching simultaneously, a compensation layer is placed on the electrode. The optimal thicknesses of the electrode and the compensation layer as well as the width of electrode have been obtained. Based on single-mode condition, an asymmetric Mach–Zehnder modulator (AMZM) has been designed and simulated by effective index method and finite-difference beam propagation method (FD-BPM). The initial phase difference between the two arms of the modulator has been achieved 0.522π in the linear region. Comparing with the typical MZM, AMZM can get a larger value of f _3dB , increased by 67.32%.     

Highly active copper-based catalyst for atom transfer radical polymerization

Atom transfer radical polymerization (ATRP) generally requires a catalyst/initiator molar ratio of 0.1 to 1 and catalyst/monomer molar ratio of 0.001 to 0.01 (i.e., catalyst concentration: 1000-10,000 ppm versus monomer). Herein, we report a new copper-based complex CuBr/N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) as a versatile and highly active catalyst for acrylic, methacrylic, and styrenic monomers. The catalyst mediated ATRP at a catalyst/initiator molar ratio of 0.005 and produced polymers with well-controlled molecular weights and low polydispersities. ATRP occurred even at a catalyst/initiator molar ratio as low as 0.001 with copper concentration in the produced polymers as low as 6-8 ppm (catalyst/monomer molar ratio = 10(-5)). The catalyst structures were studied by X-ray diffraction and NMR spectroscopy. The activator CuIBr/TPEN existed in solution as binuclear and mononuclear complexes in equilibrium but as a binuclear complex in its single crystals. The deactivator CuIIBr2/TPEN complex was mononuclear. High stability and appropriate KATRP (ATRP equilibrium constant) were found crucial for the catalyst working under high dilution or in coordinating solvents/monomers. This provides guidance for further design of highly active ATRP catalysts.     

A novel three-dimensional holographic display system based on LC-R2500 spatial light modulator

A novel holographic display system is proposed in this paper. The system takes LC-R2500, a kind of reflective liquid crystal spatial light modulator, (LC-SLM) as the core display unit, which can meet the requirement of real-time reconstruction of three-dimensional (3D) objects from holograms in free space. The relationship between hologram recording and image reconstruction is discussed, and the parameters associated with the magnification of reconstructed image over original object are determined. Experimental results of holographic display using the system are also given in the end.     

球面上紧超曲面的等谱问题

本文讨论了球面上全脐超曲面与全测地超曲面的等谱问题。     

发现于金华的浙江省卫矛科植物新记录

报道了最近在植物资源调查过程中发现的浙江地理分布新记录属永瓣藤属Monimopetalum Rehd.,新记录种永瓣藤（Monimopetalum chinense Rehd.）.     

Non-resonant magneto-optical effects in cold atoms

We report a novel nonresonant magneto-optical effect in cold atoms and present the optimized parameters of the biased magnetic field, the incident probe light intensity, and the probe detuning to obtain the maximal signal of the magneto-optical rotation. This detection scheme may further improve the stability of the cold atom clock.     

梯度洗脱优化-离子色谱-脉冲安培法分析婴幼儿配方乳粉中的糖和糖醇

建立了梯度洗脱优化-离子色谱-脉冲安培检测技术分析婴幼儿配方乳粉中麦芽糖醇、半乳糖、葡萄糖、蔗糖、果糖、乳糖6种与代谢疾病紧密相关的糖和糖醇的方法。该方法对样品的前处理、色谱柱的选择、淋洗液的梯度等色谱条件进行了优化,重点研究了淋洗液梯度对各组分分离效果的影响。将梯度洗脱程序分解为弱保留组分分离、乳糖分离、基质消除、系统平衡4个子程序,并分别对其进行了条件优化,实现了6种组分的完全分离,并有效解决了弱保留组分色谱峰易重叠、乳糖色谱峰易拖尾等现象。6种组分的线性范围为0.5~100 mg/L,相关系数（r）>0.99,方法的检出限（S/N=3）为0.06~0.40 mg/L。该方法具有分离度好、灵敏度高等优点,可满足例行分析的要求,同时也为淋洗液的梯度优化提供了可借鉴的方法。