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The dynamic fracture behavior of notched semi-circular bending(NSCB) subjected to hammer impact loading was studied by using caustics experimental method.The results show that the shear stress at the crack tip increased with the offset distance increased, and correspondingly, the crack changed from mode I to mixed mode I-II, the time from impact force loaded to crack initiation also increased, moreover, the crack deflecting angle became more fluctuating with crack propagation;the crack velocity increased rapidly under dynamic load until it reached a certain value with continual fluctuation, with the ratio of crack vertical displacement to the total vertical lengthλ> 0.8, the crack velocity sharply decreased because of the effect of the local compressive stress around the hammer;as the offset distance increased, the initial fracture toughness KIC decreased, whereas KIIC increased;while the dynamic propagation toughness increased gradually with crack propagation.

Objective: To study the anti-tumor and immunity activity of toad coat (Chantui), which is a new officinal part of Bufo bufo gargarizans., Method: The tumor weight of S180, H22, Lewis lung cancer cell inoculated in mice were compared between the groups of mice, fed with toad coat, and those which were not (control group). The average longevity of the mice with HCA fed with toad coat was also compared with the control group. The T lymphocyte transformation and NK cell killing activity were tested and compared with the control group. The condition of the mice which were fed with great dosage of Chantui (16 g x kg(-1) x d(-1)) was observed., Result: The tumor weight was remarkably reduced in the groups which were fed with toad coat compared with the control group. Tests show that toad coat can raise the activity of both T lymphocyte and NK cell. There was no obvious side-effect when the mice were fed with great dosage of toad coat., Conclusion: The results show that toad coat has a strong inhibitory activity against tumors inoculated in mice and a strong enhancement of immune activity, so it could be viewed as a new valuable safe medicinal source.