Instabilities of thermocapillary-buoyancy convection in open rectangular liquid layers

This article presents the experimental investigation on instabilities of thermocapillary-buoyancy convection in the transition process in an open rectangular liquid layer subject to a horizontal temperature gradient. In the experimental run,an infrared thermal imaging system was constructed to observe and record the surface wave of the rectangular liquid layer. It was found that there are distinct convection longitudinal rolls in the flow field in the thermocapillary-buoyancy convection transition process. There are different wave characterizations for liquid layers with different thicknesses. For sufficiently thin layers, oblique hydrothermal waves are observed, which was predicted by the linear-stability analysis of Smith Davis in 1983. For thicker layers, the surface flow is distinct and intensified, which is because the buoyancy convection plays a dominant role and bulk fluid flow from hot wall to cold wall in the free surface of liquid layers. In addition, the spatiotemporal evolution analysis has been carried out to conclude the rule of the temperature field destabilization in the transition process.     

All-Optical AND Logic Gate without Additional Input Beam by Utilizing Cross Polarization Modulation Effect

A novel design of all-optical AND gate is proposed by using cross polarization modulation effect in a semiconductor optical amplifier. In this scheme, an additional continuous-wave beam is not required as that in traditional scheme. AND output is obtained on either of two input signal wavelengths. The AND scheme is numerically simulated and experimentally demonstrated at a bit rate of 10 Gb/s successfully.     

Amplitude Regenerative Characteristics of RZ-DPSK Wavelength Converter Based on Four-Wave Mixing in SOA

We investigate the phase-preserving amplitude regenerative characteristics of the return-to-zero （RZ） differential- phase-shift-keying （DPSK） wavelength conversion based on four-wave m/xing （FWM） in a semiconductor optical amplifier （SOA）. The Q-factor and the optical signal-to-noise ratio （OSNR） before and after conversion are experimentally obtained and analysed in different input noise power levels. In both the continuous-wave and synchronous clock pumping cases, we find that there is amplitude clamping in the FWM conversion due to the gain saturation of SOA, which can suppress the amplitude fluctuation of the converted DPSK signal before and after demodulation. We have achieved 2-dB Q penalty improvement in our experiment demonstration of lOGbit/s RZ-DPSK signal with OSNR lower than 19dB.     

矩形液池热毛细对流转捩途径研究

主要研究矩形液池热毛细对流的分岔转捩. 通过测量流体内部温度振荡情况, 详细研究了热毛细对流的转捩过程和转捩途径. 实验发现, 矩形液池热毛细对流的转捩过程依次经历了定常、规则振荡、不规则振荡的阶段. 对于不同普朗特数的硅油在不同长高比情况下, 通向混沌的途径不同. 在转捩过程中, 随着温差的增加, 普朗特数在16 (1cSt) 以下和普朗特数为25 (1.5cSt)、长高比为26 的硅油热毛细对流主要以准周期分岔的转捩方式为主;而普朗特数为25 以上的则以倍周期分岔的转捩方式为主;两种分岔有时还会伴随有切分岔形式的出现.实验中还观察到了表面波动和对流涡胞振荡等现象.      

集成光波导干涉芯片的设计及特性研究

运用光波导的模式理论设计了多层集成光波导干涉芯片,对芯片的光波导结构和材料参数进行优化,并制作了集成干涉芯片.借助集成芯片的波导双通道,通过干涉获得了高对比度的远场干涉条纹.在实验误差范围内,当外界环境条件发生微小变化时,干涉条纹发生移动,符合杨氏双缝干涉理论的预期.芯片对水汽、酒精的探测灵敏度约为100ppm,并具有足够的温度稳定性.该集成干涉芯片具有低浓度环境气体检测的应用前景,可为集成高灵敏气体传感器的开发提供发展平台.     

GC－MS/MS法测定食品接触用硅橡胶制品中6种环硅氧烷迁移量

基于气相色谱－串联质谱（GC－MS/MS）建立了食品接触用硅橡胶制品中6种环硅氧烷（D4 ~ D9）向50%乙醇、95%乙醇、异辛烷迁移量的检测方法,并应用于38批次实际样品的检测。取10 mL迁移实验得到的50%乙醇浸泡液,使用2 mL正己烷萃取,经过滤后测定,95%乙醇和异辛烷浸泡液直接经过滤后测定。采用HP－5 MS色谱柱分离,多反应监测模式进行分析。结果表明,D4 ~ D9在0.05 ~ 1.00 mg/L或0.20 ~ 5.00 mg/L范围内具有良好的线性关系,相关系数（r2）不低于0.996 0。各目标物的检出限为0.02 ~ 0.07 mg/L,定量下限为0.05 ~ 0.20 mg/L,回收率为90.1% ~ 106%,相对标准偏差不大于13%。使用该方法对市面上的食品接触用硅橡胶制品进行迁移实验,发现D4~D9向50%乙醇存在迁移风险;向95%乙醇和异辛烷迁移的检出率为80%,迁移风险最大。D4 ~ D9在95%乙醇和异辛烷第3次的迁移检出率显著大于第1次,而在50%乙醇中第1次迁移和第3次迁移的检出率无明显差异。     

热毛细对流表面波空间实验研究

介绍了实践十号返回式科学实验卫星19项科学项目载荷之一:热毛细对流箱表面波空间实验研究,包括项目研究目标、意义、研究内容、空间实验模型及地面匹配实验结果等.阐述了本项目开展空间实验研究的必要性,用科学的地面实验研究数据预测和对比微重力条件下可能获得的研究结果,展望本项目可能取得的成果.