Ge20Sb15Se65硫系玻璃光子晶体光纤的中红外色散特性

硫系玻璃与石英玻璃相比具有高折射率(2.0~3.5)、低声子能量 (<350 cm^-1)、优良的中远红外透过性能(可至25 μm)等特性.本文制备了一种在中红外具有优良透过特性的无As环保型Ge₂₀Sb₁₅Se₆₅硫系玻璃材料,以此为基质材料设计了一种三层空气孔结构光子晶体光纤,利用多极法对光纤的中红外色散特性进行了数值模拟,系统研究了结构参量孔径d、孔间距Λ 以及d/Λ 对其色散特性的影响.分析表明:通过改变包层空气孔直径d或空气孔间距Λ,可灵活的调节光子晶体光纤的零色散波长向短波或长波方向移动.通过优化结构参量发现,当Λ=3 μm,d/Λ=0.35 附近变化时,可获得3~5 μm色散平坦,且色散值小于5 ps·nm^-1·km^-1的光子晶体光纤.     

Highly stereoselective synthesis of 1-cyanocyclopropane-carboxamides from 3-substituted-2-cyanoacrylamides with N-tosylhydrazones under metal-free conditions

A metal-free cyclopropanation of electron-deficient olefins 3-substituted-2-cyanoacrylamides with N-tosylhydrazones has been successfully developed. This strategy provide a simple route to the synthesis of very valuable 1-cyanocyclopropanecarboxamides with a quaternary stereogenic center in good yields and with high diastereoselectivities (up to 90% yield with 19:1 dr). The reaction could be performed in one-pot fashion and in a gram-scale from aryl aldehydes.     

Non-Markovian Dynamics of Two-level System in a Composite Environment

We have studied the non-Markovian decoherence dynamics of the two-level system in a composite environment, which consists of a spin-star environment and a boson reservoir. By use of the measures presented recently, we theoretically study the non-Markovianity of the dynamics of the model.     

Preparing an Eight-Qubit Entangled State in Cavity QED

An experimental protocol for preparing an eight-qubit entangled state in cavity QED is proposed, which is insensitive to the cavity decay and the thermal field. And the experimental feasibility of our protocol is discussed.     

Selective transformation of carbohydrates to hydroxymethyl furfural with polyaniline-based catalysts

Research on Chemical Intermediates - The efficient production of 5-hydroxymethyl furfural (HMF) from carbohydrates is achieved in the presence of polyaniline-based solid catalysts. The composite...     

固体手性材料的研制及其特性测试

利用溶胶凝胶低温合成非晶态技术,以正硅酸乙酯、γ缩水甘油醚基丙基三甲氧基硅烷和乙醇为前驱体,将手性分子葡萄糖均匀地掺入到上述体系的溶胶与凝胶中,成功地研制出无机固体手性材料样品,并对其光学极化特性、光谱特性及材料的热稳定性进行了测试.测试结果表明,样品的旋光率为-095°cm,计算所得的手征参数为155×10-7. 关键词： 溶胶-凝胶 手性分子 旋光率 手征参数     

气相色谱法测定柑桔中甲基托布津残留量

本文根据甲基托布津在一定温度下,分解放出含硫化合物的特点,建立了用气相色谱法直接测定甲基托布津残留量的方法。用丙酮提取样品,二氯甲烷液液分配净化,用带FPD气相色谱仪检测。在5～30ng范围内呈良好的线性关系。方法最低检测浓度为0.02ppm,回收率为87.3～98.2%,变异系数为2.0%。