rotational life
1.The effect of compound casting technology and compound modification on the properties of high Speed steel roll collar was studied.The results showed that compound high speed steel roll collar with high and even hardness and good bond between outer and inner layers could be gained when the modified colbalt free high speed steel in outer layer and nodular iron inner layer in connection with appropriate rotational speed of centrifugal machine,pertinent pouring interval between two kinds of the melt and moderate pouring temperature as well as surface induction heat treatment were chosen.It is indicated in industrial use that the service life of compound roll collar is higher by 5 times than that of high chromium cast iron collar.
2.The twenty experimental population life tables of Aphis craccjvora Koch were studied by regression rotational combinatorial design and the essential parameters for investigation includ-ed net reproduction rate (R0),average time of a generation (T) and innate capacity for increase (rm) at different temperature (TE),relative humidity (RH) and photoperiod (PH). Quadratic regression models were developed on the relationship between Ro,T and rm,and also in reference to TE,RH and PH.
