The opening up environment of this system is very ripe . the cpu is the at89c52 , it is very cheap . the fijnction includes the sampling of the data , operation and control , key operation , display ctc 该系统开发环境比较成熟，采用价格比较便宜的at89c52单片机做为调节器主体，完成的功能主要有数据采集、运算控制、键盘操作、显示等功能。
Past comparative - effectiveness trials have shown that older and cheaper anti - psychotic drugs are often just as good as expensive new ones , and that the costs of some pricey new procedures , such as spinal surgery , can outweigh their benefits 通过比较收益分析我们可以发现那些普通的,价格比较便宜的安定类药物和那些价格昂贵的新药一样有效,一些花费巨大的新技术例如脊柱外科技术,其花费要大于它给患者带来的收益
