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To investigate the influence of Zn-alloying on the microstructure and tensile mechanical properties of Mg–6Bi alloy after hot extrusion, a new ternary Mg–6Bi–3Zn alloy was prepared by extrusion at 300 °C. The microstructures, texture, dynamic precipitates and tensile mechanical behaviors of the extruded alloy were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), electron backscattered diffraction (EBSD) and a material testing machine at room temperature. After extrusion, the Mg–6Bi–3Zn alloy possesses a bimodal microstructure with elongated large unrecrystallized (unDRXed) grains and fine dynamic recrystallized (DRXed) grains. In addition, non-basal <20 2 _ 1>//ED, <44 8 _ 3>//ED and <11 2 _ 1>//ED textures are observed within DRXed grains due to the Zn addition, leading to texture weakening in the extruded Mg–6Bi–3Zn alloy. Zn addition facilitates the dynamic precipitation behavior, leading to a 12.2% area fraction of Mg3Bi2 precipitates with an average size of 39.2 nm. Furthermore, incorporation of Zn atoms in Mg3Bi2 phases and segregation of Zn at the grain boundary are found. The extruded Mg–6Bi–3Zn alloy exhibits a tensile strength of 336 ± 7.1 MPa and a yield strength of 290 ± 5.5 MPa, as well as an elongation of 11.5%. Therefore, Zn addition is beneficial to enhance strength and keep good ductility for the extruded Mg–6Bi–3Zn alloy. [ABSTRACT FROM AUTHOR]

[Objectives] In order to determine the antagonism relationship and mutual influence between anti-ship missiles and shipborne defensive weapons, and meet the design requirement by using quantitative methods to provide the configuration for the self-defense weapons in warships,[Methods] this paper mainly realizes the simulation of the anti-hit problem between a single anti-ship missile and a warship based on the discrete sequence method. The Monte-Carlo method is then used to carry out a discrete sequency-based assessment of a warship's air defense performance. Through this method,the convergence of the evaluation is solved.[Results] The results indicate that the diameter of the anti-ship missile,position of attack and velocity will each have an impact on the penetration effect,and the velocity effect is most obvious. The reduction of the attack distance within the range of the shipborne defense system will significantly reduce the probability of being hit;otherwise,with the reduction of the attack distance outside of the defense distance,the effect on the probability of successful interception is not significant. It is also pointed out that the reaction time of the shipborne weapon system and success rate of single interception are important factors affecting the defensive effects of a shipborne weapon system. In particular, when the speed of an anti-ship missile increases, its impact will be more significant.[Conclusions] The results of this research can provide technical support for the quantitative design of ships based on survivability.

Background: Tobacco use is a major preventable cause of death in the world. This article describes and compares tobacco use prevalence for students attending junior high schools and senior high schools in Taiwan. Methods: This report uses data from the Global Youth Tobacco Survey (GYTS) completed among 4689 junior high school students and 4426 senior high school students in Taiwan in 2004-2005. The GYTS uses a 2-stage sampling design to produce nationally representative data for junior and senior high students in general and vocational schools. Results: Higher smoking prevalence was observed among senior high (10.1% general schools and 15.9% vocational schools) than junior high (5.5%) school students. Smoking prevalence of girls in junior high (3.2%) and senior high schools (4.6% general and 11.1% vocational) was almost as high or higher than adult females' (4.3%) smoking rates. The pattern of smoking intensity across school years and type of school shows that the percentage of smokers who were experimenters (47.1%) was higher in junior high school and the percentage of smokers who were regular/established smokers (over 50%) was higher in senior high school. Conclusions: Smoking prevalence described in this report shows that there are challenges facing the tobacco prevention and control program in Taiwan. The findings suggest that schools should increase their smoking initiation prevention efforts and make available cessation programs and counseling to help students quit smoking. If effective youth tobacco control programs are not developed and implemented in Taiwan, future morbidity and mortality attributed to tobacco will surely increase, especially among women. (Contains 3 tables and 1 figure.)