以不锈钢薄板、三元乙丙橡胶和硅胶层建立的固体火箭发动机（SRM）壳体为对象, 研究了由压电陶瓷片(PZT)激励和接收的兰姆(Lamb)波在壳体中的传播问题。首先通过设置多组压电传感器检测路径, 对不同脱粘尺寸下椭圆定位法和结合椭圆法的基于概率成像（PDI）法（即改进PDI法）定位结果进行对比; 其次对不同位置, 不同概率取值下的改进PDI法成像进行对比;最后通过试验验证了成像情况。研究结果表明, 与椭圆定位法相比, 基于PZT的改进PDI法具有更高的精度和灵敏度, 且该方法可以实现对SRM钢壳体和绝热层不同脱粘位置的检测。

In this paper, a slot microring resonator with a piece of spiral feedback waveguide for CH4 sensing application is pro-posed. This sensor is based on silicon-on-insulator (SOI) substrate and with the operation wavelength in mid-infrared region. To reach high sensitivity and good selectivity, slot cross section and spiral feedback waveguide are carefully tailored. The sensor shows ppb-scale trace gas sensing potential and is easy to be packaged in integrated photonics circuits. Calculation results show that the sensitivity reaches 1.4×10-2 dB/ppm and the detection limit achieves 700 ppb in the case of Lspiral=100Lr.

The Nd³⁺ doped fluorochlorozirconate (FCZ) glass was prepared by melt-quenching method. The 3.9 μm emission from Nd3+ ions is attributed to the two-photon absorption process. The strong emission transition at 3.9 μm fluorescence peak intensity, corresponding to the ⁴G_11/2→²K_13/2 transition, is directly proportional to the NaCl concentration. With the increase of the Cl^- ions amount, the mid-infrared (MIR) luminescent intensity is significantly enhanced. Additionally, the Judd-Ofelt (J-O) parameter Ω² is larger than that of the fluorozirconate (FZ) glass, which indicates the covalency of the bond between RE ions and ligand is stronger as Cl^- ions substitution of F^- ions in chloride FZ glass. The X-ray diffraction (XRD) patterns show that the amorphous glassy state keeps the FZ glass network structure. In brief, the advantageous spectroscopic characteristics make the Nd³⁺-doped FCZ glass be a promising candidate for application of 3.9 μm emission.

A high-sensitivity sensor for multiple gases based on microring array filter and fiber loop ring-down spectroscopy system is proposed and demonstrated. The parameters of the resonators are designed so that the filtered signal from a broadband light source can be tuned with an absorption spectral line of gas. Therefore, through adding microring resonators horizontally and vertically, the number of target gases and filter range are increased. In this research, in the broad spectral range of about 0.9 μm, only the absorption spectral lines of target gases are filtered. The simulation results show that three target gases, CH₄, CO₂and HF, can be simultaneously detected by the sensing system. Owing to the fiber loop ring-down spectroscopy, the whole system is optimized in mini-size and sensitivity, and we can choose different sensing methods to enhance the measurement accuracy for high and low concentration conditions.

理论和数值研究了轴向均匀的三层波导系统中太赫兹表面等离子激元的单向传输行为, 三层系统由厚度为d的高介电常数介质层插入到低介电常数介质层和磁光半导体层中间组成。计算结果表明, 在外加磁场的作用下, 系统存在单向传输的频段。通过金属微米粒子的耦合及调节磁光半导体区域的磁场方向, 可以有效控制表面等离子体激元在三端口系统中的传播。

提出了具有PT对称性的金属-绝缘体-金属波导系统, 由两个波导耦合一个环谐振器组成, 环谐振器的上臂填充增益介质而下臂填充损耗介质。对表面等离激元在该系统的传输特性进行了研究,结果表明:通过平衡增益介质和损耗介质, PT对称性诱导的透明峰可以被清楚地看到, 并且该透明峰具有反相位的特点。

半波孔问题严重影响了倍频分束镜在高功率激光系统中的应用。为研究半波孔的产生机理，分别模拟了由高、低折射率膜层厚度失配和膜料色散失配引起的1/4波长对称规整膜系的半波孔。基于等效层理论，在Matlab平台上计算膜系的等效折射率E，绘出其对应的反射率极值包络曲线。通过研究对称膜系的等效折射率、反射率光谱和反射率包络之间的关系，从原理上分析了半波孔的大小、位置和变化趋势等特点。结果表明，膜层的厚度失配使对称膜系的等效折射率在光谱半波处产生截止带。膜层数越多，膜层厚度和膜料色散的失配越严重，则倍频分束镜的半波孔越深。

在分析液晶触摸屏的工作原理基础上,分析触摸屏专用控制器ADS7846的工作原理与控制方式。通过ADS7846与MCU的SPI接口,给出AT89S51的测量子程序流程图,提出触摸屏触点坐标的获得方法与液晶屏显示实现同步的算法,以提高设计触摸屏与液晶屏的效率,满足控制精度。