AMPEROMETRIC DETECTION AT A CARBON-FIBER ARRAY RING GLASSY-CARBON DISK ELECTRODE IN A WALL-JET CELL

A wall-jet cell incorporating a carbon fibre array ring/glassy-carbon disk electrode has been constructed, and characterized by the cyclic voltammetry and flow-injection techniques. The ring (composed of several microdisks) and glassy-carbon disk electrode, can be used separately for different purposes, e.g., detection in solution without a supporting electrolyte, collection/shielding detection with dual-electrode and voltammetric/amperometric detection with series dual-electrode. The electrode shows better collection and shielding effects than usual ring-disk electrode in quiescent solution and the series dual-electrode in a thin-layer flow-through cell. The detection limit at the ring electrode is comparable with that at a conventional-size electrode, and has been used in the mobile phase without a supporting electrolyte, proving to be a promising detector for normal-phase liquid chromatography.

PCM控制的新型气液位置伺服系统的研究

本文提出了一种新型气液缸和气液位置伺服系统。该系统采用气液连动控制，充分发挥液压与气动各自的优点，大大提高了位置控制精度，同时克服单纯气动的特点。在气液回路上，利用两位三通阀、“ＰＣＭ”阀组及油开关阈实现分区控制和准确定位，解决了快速性和定位精度之间的矛盾，通过分析和实验研究表明，此方案是可行的。