质谱仪的自动供样系统设计

本文介绍以AT89C52单片机为主控核心,采用电机驱动方式切换被测样品,有供样方式切换、测量时间设置、显示样品号等功能,广泛适用于各种固相、液相分析仪的自动供样。

农产品检验机构的样品管理

为了保障农产品样品的准确性,从样品的采集到检验完毕、留样等各个环节,都应进行严格的管理,以防样品在某些过程中被污染,使其符合检验条件,有效减少被检样品的检验风险。要想保证农产品检验结果的准确性,所检验样品是否具有代表性,在检验过程中起着举足轻重的地位。所以,对于样品从采集到检验完毕,都应进行严格的管理,以防样品在此过程中被污染。被污染的样品不仅影响检验结果的准确性,还需要对检验结果异常的农产品进行再次复检,

The Demand Investigation and Suggestions of the Supply System of Preschool Education in Western Areas of China

Nowadays, preschool education has become the weak part of eduction. Thus, the supply system of preschool education has been heatedly discussed accordingly.This thesis makes some suggestions for the supply system innovation of preschool education in western areas, based on the sampling surveys in Yibin.