Papers by Author: Yu Tang

Abstract: Abstract. Water-extracting enzyme from plants is used in practice because of simple and low cost. The sweet potato was taken as material to extract -amylase, the optimized parameters were studied. The results showed that the optimized parameters were as follows: extraction temperature 60°C, the level of reducing agent NaHSO3 1.5 g/L, the ratio of water to sweet potato 2:1, pH 5.0-5.5, extraction time 0 h. Under the optimum technological conditions, the β-amylase activity was 113096.9±2445.7 U/g. The study of β-amylase from sweet potato is of great theoretical and practical significance to the β-amylase industrialization production.

Abstract: In order to minimize the fluctuation of gear transmission error (GTE) about the planetary gear transmission. A method was developed to deciding tooth profile modification curves of planetary transmission. According to the condition of the invariable design load, computing the dynamic characteristics of the planetary transmission system under modified and un-modified gear. At the same time, the compare is carried through of the dynamic characteristics for modified and un-modified gear. The results of the dynamic calculation indicate that the profile modification method can make the amplitudes of gear mesh stiffness change calmness and reduce the amplitudes of gear mesh stiffness by this method in paper. At last, the conclusion can be obtained that the tooth profile modification can reduce the vibration and noise of the planetary transmission system.

Abstract: In this paper, a Drill Point Simulation System (DPSS) which is being developed at Northeastern University is presented. By means of DPSS, the geometric models of the helical drill points were shown after inputting their design parameters. Then, the grinding parameters of the helical drill points were produced. According to the grinding parameters, the helical drill points were ground by the SD helical drill point grinder which was developed at Northeastern University. Furthermore, drilling tests were performed on aluminum sheet workpieces to investigate drilling performance of the helical drill points. In addition, the relationships between the geometric parameters of helical drill points and their grinding parameters also were derived.