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In order to study the critical ricochet velocity and critical penetration velocity of tungsten alloy rod obliquely penetrating a finite-thickness metal plate, experiment and numerical calculation of tungsten alloy rod impacting on homogeneous armor steel plate with a thickness of 30mm at an angle of 60° were carried out. Compared the experimental and numerical results with the results using models, it is found that, the results of the ricochet models proposed by Tate, Rosenberg and Steven B for semi-infinite thick plate are quite different from those of experiment and numerical calculation, so they can not be applied to the ricochet situation of finite-thickness plate. The critical penetration velocity model proposed by De Marre and Zhao are in good agreement with the numerical and experimental results, which can predict critical penetration velocity of tungsten alloy rod obliquely penetrating a finite-thickness metal plate with large impact angle. The penetration depth of the projectile under the critical ricochet velocity is about 1/3 of the thickness of the target plate, and the angle between the ejection trajectory of the fragments produced by projectile and target plate and projectile penetration trajectory is exactly 90° in the first penetration stage.

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In acute nonvariceal upper gastrointestinal bleeding, diagnostic failure is associated with higher morbidity and mortality. The data from this study emphasize the importance of good preparation before the procedure and adequate removal of blood during emergency endoscopy procedures.

This paper investigates a unified theory to derive vector network analyzer calibration algorithms based on the T-matrix representation, by which means the line-reflect-match (LRM), line-reflect-match-match (LRMM), and the line-reflect-reflect-match (LRRM) calibrations are formulated. The proposed calibration theory is more general than other versions of LRM, LRMM, and LRRM in that an arbitrary known two-port device can be used as the line standard L, rather than a perfect thru or transmission line. Experimental verifications of the proposed theory using on-wafer calibrations from 0.5 GHz to 110 GHz are given.

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