内通道气帘的设计与分析

保持光传输通道内单一均匀的低吸收系数气体,对削弱内通道中的气体热效应有重要意义。采用气帘作为封装设备,对气帘的结构进行了设计。取气帘入口气体为氮气,出口气体为空气,借助现有计算流体力学软件FLUENT提供的组分输运模型,对气帘进行了数值模拟。结果表明,气帘入口段形成的平面射流可以阻挡外界空气的回流;在氮气与氧气相混合的区域内,尽管气体密度存在一定起伏,但气体密度变化的梯度方向与光传输方向基本是平行的,这种密度起伏只会对光场相位的活塞项产生影响,不会影响激光的远距离传输。最后,对气帘的性能进行了实验测试,实验结果表明,设计的气帘能够对管道内的气体进行密封,并避免了较大光程差的引入。     

嵌入式处理器的定点化运算单元设计

为了满足基于嵌入式处理器的音频解决方案的需要,提出了一种嵌入式处理器中高精度、多功能的定点化运算单元(FPU)。FPU由移位、舍入、饱和3个部分组成。通过对FPU的实现和验证,证明FPU能够显著提高嵌入式处理器定点化操作的速度。     

电气设备绝缘系统局部放电检测技术研究

国内SF6气体绝缘类的电气设备常发生局部放电故障,影响电力系统的安全稳定运行。针对这种情况,文中提出了基于电气设备局部放电的超声波检测技术,对电气设备进行局部放电故障检测与诊断,同时对电力变压器的在线监测进行诊断,最终给出电力变压器的检测图谱。通过使用超声波对SF6气体绝缘类电气设备进行实例验证,结果表明采用超声波技术可以准确地检测出电气设备的电晕放电、悬浮放电等故障。     

基于量子级联激光器的气体检测研究

随着社会的发展,对基于激光光谱技术的快速、灵敏和选择性气体探测的需求日益增加,量子级联(QC)激光器特有的高输出功率、宽调谐范围和能够在室温或者接近室温下工作的特性使它成为气体遥测的理想光源.详细描述了QC激光器,介绍了基于室温脉冲QC-DFB激光器的典型的中红外激光光谱实验装置,并探讨了QC激光器应用于气体检测的广阔前景.     

智能气体监控器设计

针对监测有害气体产品的缺点,综合运用自动控制、气电转换、气敏传感及语音报警等先进技术,设计并开发了集一机多能、一机多用、自动控制及自动管理于一体的智能气体监控器.由于现实世界的大量需求,该设计在交通、消防、工厂、矿井及家庭等场所具有广泛的应用前景,不仅对保证生命财产安全具有重要意义,而且在系统分析和设计方法学上也有一定的学术参考价值.     

Reversible Formation of g‐C3N4 3D Hydrogels through Ionic Liquid Activation: Gelation Behavior and Room‐Temperature Gas‐Sensing Properties

Many unique properties arise when the 3D stacking of layered materials is disrupted, originating nanostructures. Stabilization, and further reorganization of these individual layers into complex 3D structures, can be essential to allow these properties to persist in macroscopic systems. It is demonstrated that a simple hydrothermal process, assisted by ionic liquids (ILs), can convert bulk g‐C₃N₄ into a stable hydrogel. The gelation occurs through delamination of the layered structure, driven by particular interactions between the IL and the carbon nitride sheets, forming an amphiphilic foam‐like network. This study employs spectroscopic and computational tools to unravel the gelation mechanism, and provides a rational approach toward the stabilization of 2D materials in hydrogels. The solution‐processable hydrogels can also be used as building blocks of complex devices. Chemiresistive gas sensors employing g‐C₃N₄ 3D hydrogels exhibit superior response at room temperature, enabling effective gas sensing under low power conditions.     

Solution‐Processed Nanoporous Organic Semiconductor Thin Films: Toward Health and Environmental Monitoring of Volatile Markers

Porous materials are ubiquitous in nature and have found a wide range of applications because of their unique absorption, optical, mechanical, and catalytic properties. Large surface‐area‐to‐volume ratio is deemed a key factor contributing to their catalytic properties. Here, it is shown that introducing tunable nanopores (50–700 nm) to organic semiconductor thin films enhances their reactivity with volatile organic compounds by up to an order of magnitude, while the surface‐area‐to‐volume ratio is almost unchanged. Mechanistic investigations show that nanopores grant direct access to the highly reactive sites otherwise buried in the conductive channel of the transistor. The high reactivity of nanoporous organic field‐effect transistors leads to unprecedented ultrasensitive, ultrafast, selective chemical sensing below the 1 ppb level on a hundred millisecond time scale, enabling a wide range of health and environmental applications. Flexible sensor chip for monitoring breath ammonia is further demonstrated; this is a potential biomarker for chronic kidney disease.     

HoCoO_3纳米材料的结构改性与气敏性能

利用溶胶–凝胶法成功合成了Cu2+掺杂改性的HoCoO3纳米材料。经X射线粉末衍射(XRD)仪和扫描电镜(SEM)表征后发现,所得HoCoO3纳米材料具有纯相的钙钛矿结构,其晶粒粒径为50~130 nm。将改性及未改性HoCoO3纳米材料分别制成气敏元件,并对其电性能和气敏性能进行对比研究,结果发现Cu2+掺杂可以明显降低HoCoO3气敏元件的电阻,并显著提高其对汽油的灵敏度和选择性。这表明Cu2+掺杂改性的HoCoO3纳米材料将来极有可能成为一种良好的汽油敏感材料。     

宽带CARS技术用于气体温度的测量

本文报道了用宽带CARS技术测量高温空气的温度及其实时的升降过程。结果明显地优于有滞后效应的常规热电偶测试方法。