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Lingling Ren,Huimin Gu,Wei Wang,Shuai Wang,Chengde Li,Zhenbiao Wang,Yuchun Zhai,Peihua Ma 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.1
Despite showing considerable potential, wire arc additive manufacturing (WAAM) has been limited to producing Al–Mgalloys. As the addition of Sc can improve the mechanical properties of Al–Mg alloys, in this study, Al–Mg–Sc alloy depositswith different Sc contents were prepared by a WAAM process. The porosity, microstructure, and mechanical properties ofthe deposits were studied. At Sc contents less than 0.15%, Sc was completely dissolved in the Al matrix without grain refinement,and the mechanical properties were slightly improved. At a Sc content of 0.3%, the primary Al3Scphase precipitatedout of the as-deposited body, resulting in an abrupt change in the microstructure, significant grain refinement, significantlyincreased tensile strength and yield strength, with a tensile strength, yield strength, and elongation of 372 MPa, 270 MPa,and 22.5%, respectively. Following heat treatment at 350 °C for 1 h, the grain boundaries were refined and the secondaryAl3Scphase was precipitated. Furthermore, the tensile strength and yield strength were significantly increased to 415 MPaand 279 MPa, respectively, and elongation decreased to 18.5%. At a Sc content of 0.45%, due to the aggregated precipitatedphase, the coarsened grain boundaries and the limited solid solution amount of Sc in the α(Al) matrix (~ 0.25%), themechanical properties were not further improved compared with the deposit with Sc content of 0.3%. Thus, based on economicconsiderations, the optimal Sc content was 0.3%. Owing to their enhanced mechanical properties, WAAM-producedAl–Mg–Sc alloys are expected to have a wide range of applications in aviation, aerospace.
Granularity and Laxative Effect of Ultrafine Powder of Dendrobium officinale
DanDan Luo,Chao Qu,ZhenBiao Zhang,JianHui Xie,LieQiang Xu,HongMei Yang,CaiLan Li,GuoSheng Lin,HongFeng Wang,ZiRen Su 한국식품영양과학회 2017 Journal of medicinal food Vol.20 No.2
Constipation is a common disorder that is a significant source of morbidity among people around the world ranging from 2% to 28%. Dendrobium officinale Kimura et Migo is a traditional herbal medicine and health food used for tonicity of the stomach and promotion of body fluid production in China. This study aimed to prepare the ultrafine powder of Dendrobium officinale (UDO) and investigate its laxative effect and potential mechanism in mice with diphenoxylate-induced constipation. Results indicated that the mean diameter (d50) of UDO obtained by ball milling was 6.56 lm. UDO (62.5, 125, and 250 mg/kg, p.o.) could significantly enhance the gastrointestinal transit ratio and promote fecal output. Moreover, UDO treatment resulted in significant increases in the serum levels of acetylcholinesterase (AChE), gastrin (Gas), motilin (MTL), and substance P (SP), and obviously decreased serum contents of somatostatin (SS). Taken together, UDO, which can be easily obtained through milling to a satisfactory particle size, exhibited obvious laxative effect in diphenoxylate-induced constipated mice, and the mechanism might be associated with elevated levels of AChE, Gas, MTL, SP, and reduced production of SS. UDO has the potential for further development into an alternative effective diet therapy for constipation.