By means of high speed gas stream compound with coaxial cutting gas for pulsed Nd:YAG laser on cutting of ceramics,the technological parameters affected on the thickness of re cast layer and the exiting of crack in re cast layer were studied.

The study on the effects of fleedback from classroom teachers of second languages,and especially of recasts,is of much importance,not only theoretically but also empirically, when conducting a comprehensive research on the quantity and quality of such feedback.

The long-held belief that recasts are implicit in nature is now open to challenge.

This paper discusses the concept and nature of recasts, the roles they play in second language acquisition and their related theoretical background.

This empirical study is designed to investigate the effects of corrective feedback on Chinese low-intermediate middle school students, with an attempt to research into the role of two typical implicit corrective feedback (recasts and elicitations) on middle school students’learning the third person singular form of simple present tense verbs in task-based interactional activities.

Although recasts have been generally proved to be a common corrective feedback strategy in L2classroom interaction both home and abroad, present research has not provided a complete picture of the effects of recasts, particularly that in Chinese EFL setting.

According to the studies abroad,recasting can help students correct errors.

In this paper,the characteristic & application of gravity casting are discussed.

The influences of aging effect, gravity casting and adjusted pressure casting on the mechanical properties of ZL101A T6 aluminum alloy are compared by experiment.

The current research and application status of the creep resistant magnesium alloys used for high pressure die casting and for gravity casting in automobile were reviewed.