Ion Mobility Sensor In Environmental Analytical Chemistry—Concept And First Results

Abstract

Ion mobility spectrometry is a technique for generating ions at atmospheric pressure via ion-molecule reactions, and for analysing them in an ion drift tube.

The time required for the ions to traverse the length of the drift tube is mainly a function of the mass and the charge of the ions. Besides, ion shape and polarizability also affect the drift time.

Ion mobility spectrometry does not allow structural identification and quantification of unknown substances in mixtures. However, under certain boundary conditions it provides selective fingerprints of the substances to be observed, and operates at the ppbv concentration level and the millisecond time scale.

Through further miniaturization of a recently developed instrument of this type an ion mobility sensor is to be constructed. This sensor includes drift channel, operating shutter, collecting electrode, electronic data acquisition and translation board. The sensor makes possible to obtain real-time ion mobility spectra.

We present and discuss the concept of a small ion mobility spectrometer, its operation principle and first results on the way towards its further miniaturization.     

Compact zoom lens unit for camera phones

We present a novel approach to the miniaturization of an imaging system with high resolution and high optical magnification for camera phones. An optical zoom system with a mechanical shutter has been designed and developed, the mechanical shutter being necessary to assure high image quality. The shutter is integrated with the zooming lens group, which allows the zoom lens unit to be downsized. Performance of the zoom lens unit accommodates an image sensor of over five-mega-pixels and fulfills all the requirements of a camera phone.     

新型小型化牙科扫描仪探头的光学系统设计

为解决牙科扫描探头小型化问题,基于结构光三维重建算法,创新性地设计出一种投影与成像共孔径设置的小型化牙科三维扫描仪探头光学系统。系统采用分视场共孔径技术,部分视场用于实现投影功能,另一部分视场用于实现成像功能,投影区域和成像区域存在公共区域。仿真实验给出了在扫描范围为46×35mm2内的系统性能,借助LightTools软件做了照明分析仿真,证明了系统光路的可行性。     

Spectral Characteristics of Raman Emissions from Miniature Pulsed Optically Pumped Far Infrared Laser

A miniature FIR laser with a sample-tube in 10 or 20cm length were constructed, and the laser's cavity consisted of a pair of metallic meshes, with NH3 molecules as active medium pumped by a TEA-CO2 laser, a series of FIR laser lines were observed. By taking account of the properties of the Fabry-Perot cavity and the gain characteristics of Raman transitions in the miniature optically pumped FIR laser, the spectral characteristics of the FIR laser were studied.     

A miniaturized arrayed assay format for detecting small molecule-protein interactions in cells

Background: Two complementary approaches to studying the cellular function of proteins involve alteration of function either by mutating protein-encoding genes or by binding a small molecule to the protein. A mutagen can generate millions of genetic mutations; correspondingly, split-pool synthesis can generate millions of unique ligands attached to individual beads. Genetic screening of mutations is relatively straightforward but, in contrast, split-pool synthesis presents a challenge to current methods of screening for compounds that alter protein function. The methods used to screen natural products are not feasible for large libraries composed of covalently immobilized compounds on synthesis beads. The sheer number of compounds synthesized by split-pool synthesis, and the small quantity of individual compound attached to each bead require assay miniaturization for efficient screening.Results: We present a miniaturized cell-based technique for the screening of ligands prepared by split-pool synthesis. Spatially defined droplets with uniform volumes of approximately 50–150 nanoliters (depending on well dimensions) are arrayed on plastic devices prepared using a combination of photolithography and polymer molding. Using this microtechnology, approximately 6,500 assays using either yeast cells or mammalian tissue culture can be performed within the dimensions of a standard 10 cm petri dish. We demonstrate that the biological effect of a small molecule prepared by split-pool synthesis can be detected in this format following its photorelease from a bead.Conclusions: The miniaturized format described here allows uniformly sized nanodroplets to be arrayed on plastic devices. The design is amenable to a large number of biological assays and the spatially arrayed format ensures uniform and controlled ligand concentrations and should facilitate automation of assays. The screening method presented here provides an efficient means of rapidly screening large numbers of ligands made by split-pool synthesis in both yeast and mammalian cells.     

超轻小宽视场高分辨无人机机载相机光学系统设计

随着航空航天成像技术的发展,遥感成像观测系统需求不断增加,为了简化光学系统的加工装配复杂度,缩小光学系统体积,该文提出了一种低成本、小型化遥感成像光学系统设计方法。在全球面镜的基础上,配合氟化钙等低色散材料,设计了一种焦距2 000 mm,适用于5.08 cm（2 inch）探测器的光学成像系统,该系统在50 lp/mm处MTF（调制传递函数）优于0.41,体积与R-C系统接近,系统的球面主、次镜避免了在加工装调时使用非球面补偿器,降低了加工装调成本。同时设计了新型百叶窗遮光罩结构,有效避免了传统外遮光罩结构形式体积过大的问题,规避角大于12°后PST（点源透射比）值均小于10⁻⁶,且光学体积仅为ϕ227×421 mm³,远小于传统外遮光罩形式。该系统具有低成本、结构小型化、轻量化、像质优良、杂散光抑制良好等优点,在工程应用中可以满足航空航天成像系统的使用要求。

     

量子点微型光谱传感技术在水质实时监测中的应用

随着我国城市化进程加快和工业化程度加大,水环境保护问题愈发突出。水质的实时监测是水质治理的重要前提之一。从水质实时监测发展历程中的各项技术谈起,介绍和比较多种光学传感法,并着重聚焦于新兴的量子点微型光谱传感技术。量子点光谱仪是基于胶体量子点材料的重建式微型光谱仪,具有成本较低、性能优良、发展潜力大等诸多优势,目前已实际应用到水环境实时监测中。最后总结并展望了水质实时监测技术未来的发展方向。     

全同轴型Marx发生器的研制与场路协同仿真

针对Marx发生器小型化的应用需求和快前沿脉冲下Marx发生器内部存在波过程的实际情况,开展了全同轴结构Marx发生器的研制和场路协同仿真。Marx发生器采用基于环形电容器、环形开关、锥形隔离电感、轴心单边充电的全同轴结构方案,避免结构偏心带来的局部场增强效应。在CST软件中建立了Marx发生器实际结构模型,利用时变材料和场路协同仿真功能实现了充放电过程的动态仿真,仿真结果显示出快前沿脉冲下Marx发生器内部存在波过程。据此可以对绝缘设计进行优化,并分析结构参数对输出脉冲的影响。研制的5级Marx发生器体积小于0.015 m³,可在10 μs内充电至88 kV,对40 Ω传输线输出峰值电压210 kV的高压脉冲,峰值功率约1.1 GW,脉冲前沿5.3 ns,半高宽11.2 ns。     

碘量法测定葡萄糖含量的小量化与绿色化研究与实践

碘量法是测定葡萄糖含量的常规分析方法,也是定量分析化学实验常开设的综合性实验。对传统教材中的碘量法测定葡萄糖含量实验内容进行了小量化改造,并研究了氢氧化钠用量及滴加速度、反应温度、放置时间、酸的用量、滴定震荡速度及淀粉加入时刻等影响因素对碘量法测定葡萄糖含量的影响。实验结果表明,小量化滴定能够达到常量滴定分析要求的精密度与准确度,可大幅度降低实验消耗、节省实验经费80%以上,使学生树立绿色化学思想和环境保护意识,全面提高人才的培养质量和效益。     

15 mm～300 mm宽光谱变焦光学系统设计

变焦光学系统不仅适用于照相、监控以及显微等日常生活中,还被广泛应用于航空航天及国防建设等领域。随着应用范围的扩大,对其性能指标的要求也越来越多,该文设计了一款15 mm ~300 mm的宽光谱四组元连续变焦光学系统。该系统采用正组补偿结构实现了20^×的光学变焦,工作在450 nm~900 nm光谱范围,工作温度范围为−40 ℃~60 ℃;采用了18片球面玻璃镜片,总长160 mm,最大口径66 mm,长焦F数优于5,系统结构紧凑,满足小型化要求。系统在可见光波段,中心视场的调制传递函数（modulation transfer function, MTF）>0.4@145 lp/mm,全视场MTF>0.2@145 lp/mm;在近红外波段,中心视场MTF>0.45@60 lp/mm,全视场MTF>0.2@60 lp/mm。从设计结果可以看出,该设计满足高性能指标要求,对于宽光谱、大变倍比、小型化的变焦光学系统设计具有一定的参考意义。