乙炔水合制乙醛的演示实验-气相非汞水合法

本人采用一支试管,既发生乙炔又同时使乙炔和水蒸气一起与催化剂磷酸釜接触,在250-400oC温度下,直接水合生成乙醛。本实验可作演示实验、学生实验,也可用于定性实验中的少量制备。     

简易的光纤拉断法

对150μm以下的石英光纤或玻璃光纤可不用专门工具切割,采用拉断法。先剥去护套(紧包型可用火烧掉),然后左手握光纤,右手用尖咀钳之类的工具夹住裸光纤部分,沿光纤轴线方向用力拉断光纤(不是折断和夹断)。由于光纤的圆对称性和均匀的应力分布,这样拉断的光纤,其断面大多能平整如镜,且垂直于纤芯。为避免夹伤和增加摩擦     

A GaN AlGaN InGaN last quantum barrier in an InGaN/GaN multiple-quantum-well blue LED

The advantages of a GaN–AlGaN–InGaN last quantum barrier(LQB) in an InGaN-based blue light-emitting diode are analyzed via numerical simulation. We found an improved light output power, lower current leakage, higher recombination rate, and less efficiency droop compared with conventional GaN LQBs. These improvements in the electrical and optical characteristics are attributed mainly to the specially designed GaN–AlGaN–InGaN LQB, which enhances electron confinement and improves hole injection efficiency.     

A GaN-AIGaN-InGaN last quantum barrier in an InGaN/GaN multiple-quantum-well blue LED

The advantages of a GaN-AlGaN-InGaN last quantum barrier （LQB） in an InGaN-based blue light-emitting diode are analyzed via numerical simulation. We found an improved light output power, lower current leakage, higher recombi- nation rate, and less efficiency droop compared with conventional GaN LQBs. These improvements in the electrical and optical characteristics are attributed mainly to the specially designed GaN-AlGaN-InGaN LQB, which enhances electron confinement and improves hole injection efficiency.