Synthesis of robust tracking systems with specified transfer matrices

In this paper we study linear time-invariant multivariable systems in which the compensators consist of both feedforward and feedback parts. Firstly, a necessary and sufficient condition for the system to be an internally stable robust tracking system is obtained. Secondly, the class of attainable transfer matrices from reference signal to plant output of internally stable robust tracking systems is clarified. Thirdly, a simple method is proposed for specifying two feedback properties, i.e., sensitivity and stability margin. Finally, based on these results, we propose a synthesis procedure of robust tracking systems with desirable transient responses, sensitivity and stability margin     

Effect of Japanese Green Tea oh Nitrosamine Formation in Vitro

The effect of Japanese green tea extract and various phenolic components of green tea on nitrosamine formation in vitro were investigated. We found that green tea extract seems to enhance the nitrosation of four secondary amines under acidic conditions; however, there exists an optimum concentration for the catalytic effect on nitrosamine forma ion. Among various polyphenols in Japanese green tea, only catechins catalyze nitrosamine formation, while pyrocatechol, pyrogallol, and gallic acid inhibit the reaction. No significant effect on the nitrosation reaction could be observed in the presence of either flavonols or flavones.