The World Federation of Democratic Youth and Bruno Bernini's encounter with Mao's China

This paper examines the role played by adult-led youth groups in providing avenues for early encounters between Italian and Chinese Communists in the '50s. In particular, it focuses on the links built up within international organisations linked to the Soviet-sponsored peace movement at a time when direct exchange between the Italian and Chinese Communist parties had yet to start. Relying on a large variety of primary and secondary sources, some of which have never been used before, I provide evidence of how participation in Soviet-led international organisations made early political contacts and interactions possible. The focus is on Bruno Bernini, whose personal experience in China is examined within the context of the World Federation of Democratic Youth's policies and initiatives in the early and mid-'50s

780nm InGaAsP/InGaP/AlGaAs高功率半导体激光器

采用MOCVD生长了InGaAsP/InGaP/AlGaAs材料系分别限制异质结构(SCH) 的高功率半导体激光器.对于厚度为10nm 的单量子阱,通过计算量子阱增益谱优化了器件的激射波长. 在室温下外延材料的荧光峰值波长为764nm,由于In原子的记忆效应(In carry-over effect)和As/P的替换作用使材料的InGaP/AlGaAs界面不陡峭,通过在InGaP/AlGaAs间长一层5nm的GaAsP大大改善了界面质量. 器件的阈值电流从界面改善前的560mA 减小到改善后的450mA, 斜率效率也从0.61W/A提高到了0.7W/A, 特别是单面最大输出功率已经从370mW 增加到了940mW,发生灾变性光学损伤时的工作电流已经由原来的1100mA 上升为1820mA

大功率GaInP／AlGaInP半导体激光器

制备了大功率实折射率GaInP／AlGaInP压应变分别限制量子阱激光器．所用外延材料在15°偏角的GaAs衬底上由有机金属气相外延一次外延生长得到．制备的激光器具有双沟脊波导结构，条宽和腔长分别为3和900μm，前后端面分别蒸镀5％的增透膜和95％的高反膜．分析了室温连续激射时激光器的光电输出性能．阈值电流的典型值为32mA，光学灾变阈值为88mW，功率为80mW时的工作电流为110mA，斜率效率为1W／A，串联电阻为3Ω．基横模光输出功率可达60mW，60mW时的平行结和垂直结的远场发散角分别为10°和32°，激射波长为658．4nm．器件的内损耗为4．1cm^-1，内量子效率达80％，透明电流密度为648A／cm^2