Applications of polydimethylsiloxane in analytical chemistry: A review

Silicones have innumerable applications in many areas of life. Polydimethylsiloxane (PDMS), which belongs to the class of silicones, has been extensively used in the field of analytical chemistry owing to its favourable physicochemical properties. The use of PDMS in analytical chemistry gained importance with its application as a stationary phase in gas chromatographic separations. Since then it has been used in many sample preparation techniques such as solid phase microextraction (SPME), stir bar sorptive extraction (SBSE), thin-film extraction, permeation passive sampling, etc. Further, it is gaining importance in the manufacturing of lab-on-a-chip devices, which have revolutionized bio-analysis. Applications of devices containing PDMS and used in the field of analytical chemistry are reviewed in this paper.     

高超音速进气道粘性流场的分块计算

本文采用一种隐式迎风型TVD格式求解二维Navier—Stokes方程，使用分块技术数值模拟了某超音速进气道在飞行马赫数2．291和2.557两种状态下的流动，给出了该进气道的内外流场结构、捕获面积比、表面压力分布、总压恢复系数等等。     

多路光导纤维探测系统的设计和实验结果

本文给出了多路光导纤维探测系统的原理及初步实验结果。探测系统的空间分辨能力为1.2mm,时间分辨能力由采样速率来决定。利用本系统测量了氦灯中He I 5875体发射系统的时间—空间变化。其结果与理论分析相吻合。     

物理实验课的启发式教学初探

文章通过课堂教学实例论述了实验课启发式教学的重要性 ,是对教学方法与模式改革的一种尝试     

一种无缝棱镜导光管光线传输原理的研究

目前市场上已有的棱镜导光管均为国外产品,且价格极高．为此,作者研制了一种新型无缝棱镜导光管．该导光管采用拉制工艺制成,没有缝隙且成本较低,仅为国外棱镜薄膜价格的15%左右．当光源位于导光管的轴线上时,无缝棱镜导光管能够将光源的光线以全反射的方式向前传播,提高了光线的传输效率,因此它具有效率高、成本低的特点．文中详细介绍了光线在该系统中发生全反射的原理和过程,并简单介绍了该系统在高温高湿的混凝土养护室中的应用．应用结果表明,该系统能够为养护室提供合适的工作照度,且降低了维护成本并提高了安全性．     

溢流阀回油口压力对进口压力的影响

本在忽略溢流阀阀芯所受到液动力的前提下，分析了溢流阀串联联接时的静态受力情况，进而推出了溢流阀回油口压力对进口压力影响的有关表达式。     

光导中喇曼放大实验的观察

本文报道了光导中单束激光无聚焦多次反射激励喇曼介质H_2,使得同步入射的H_2的斯托克斯种子光得到耦合放大,放大系数大于2,并且光束质量明显提高     

Light Guide Systems for the Ultraviolet Region of the Spectrum

Whereas diverse and highly refined fiber optics have long been in technical use for the conduction of visible light, traditional but expensive silica glass lenses and prisms have had to be utilized until quite recently for the transmission of ultraviolet light. The reason for this was the lack of suitable materials. UV light cannot be transported to any technically useful extent either with pure glass-glass (core and sheath materials) light guides or with plastic-plastic light guides. UV light guides for wavelengths down to 200 nm can be produced by combination of a silica glass as the core material with a tetrafluoroethylene-hexafluoropro pylene copolymer or methylpolysiloxane as the sheath material. Fiber optics of this type constitute a new aid for medical technology, medicine, and many technical and scientific fields, whose range of applications cannot yet be fully envisaged.