Spray behavior is regarded as one of the main factors influencing engine performances, fuel consumption and emissions for diesel engines. Under high injection pressure, diesel spray behaviors are extremely sensitive to the nozzle internal geometries, especially the geometric structures of orifice entrance. Based on the synchrotron radiation X-ray tomography technique, the 3D digital models of nozzle tips can be constructed. A new automatic method is presented to reveal the inlet structures according to these nozzle orifice models. The planes passing through the orifice axis are determined and used to cut the models, and then the corresponding cutting images are applied to measure the inlet chamfer radii around the orifice axis automatically. The orifices of a single-hole nozzle and an eight-hole nozzle are measured according to this method. The results show that this method can automatically measure the orifice inlet chamfer radii around the orifice axis with high precision. The obtained inlet chamfer radius shows the whole profile of the orifice entrance, which is a precise feedback for nozzle designing and manufacturing, and it also provides precise geometrical boundary conditions for the study of spray behaviors.

数值模拟了一种利用高非线性光纤(HNLF)中的交叉相位调制(XPM)效应实现归零(RZ)码到非归零(NRZ)码的转换方案，讨论了RZ信号的占空比对转换后NRZ码性能的影响。转换后NRZ码的性能受输入RZ信号占空比的影响，当RZ信号占空比在30%~50%范围内可实现较好地转换。同时，实验实现了码率为10 Gb/s、占空比为33%的 RZ码到NRZ码的转换，对比了连续探测光的原始谱和展宽谱，给出了转换前后信号的典型眼图和误码率(BER)特性。结果显示，在误码率为10-9时，由RZ码转换到NRZ码引入的功率代价不到1 dB。进一步的实验验证了这种方案在大于160 Gb/s或更高码率下的可行性。

采用分布傅里叶方法模拟了光子晶体光纤超连续谱的产生，分析了超连续谱的产生机理与不同光子晶体光纤超连续谱的特点，分析结果表明，在正常色散区可以获得高质量超连续谱。优化光子晶体光纤结构，利用脉宽为100 fs、峰值功率为500 W的高斯脉冲通过10 m长的优化光子晶体光纤，在1 550 nm波段获得了宽度为210 nm、平坦度为3 dB的超连续谱。

数值仿真分析了利用高非线性光纤(HNLF)的交叉相位调制(XPM)效应实现归零(RZ)码到非归零(NRZ)码的转换，并讨论了RZ信号占空比、光纤色散对转换后NRZ信号Q因子的影响。数值结果表明：转换后NRZ码的Q值受输入RZ信号占空比的影响；而且RZ信号与连续的探测光之间的色散差也严重影响转换后NRZ信号的Q因子值。