Enhanced strengthening by two-step progressive solution and aging treatment in AM50-4%(Zn,Y) magnesium alloy

AM50-4%(Zn,Y)alloy with a Zn/Y mole ratio of6:1was subjected to thermal analysis,and the results were used for designing a two-step progressive solution treatment process.The effects of solution and aging treatments on the microstructure and mechanical properties of the AM50-4%(Zn,Y)alloy were investigated using OM,XRD,SEM/EDS,TEM,tensile test and hardness test.The experimental results demonstrated that the two-step progressive solution treatment could make theΦandβphases sufficiently dissolve into the matrix which possessed higher supersaturated degree of the dissolved solute compared with the one-step solution treatment.This resulted in a certain enhancement of the precipitation strengthening effect during the subsequent aging process.The precipitation of theФphase had a greater impact on the comprehensive mechanical properties of the alloy thanβphase precipitation when the aging treatment was performed at180℃.The peak aging strength of the AM50-4%(Zn,Y)alloy which was subjected to the two-step progressive solution treatment process(345℃for16h and375℃for6h)was obtained after the aging treatment at180℃for12h.

电子结肠镜下4%甲醛溶液治疗宫颈癌放疗后放射性出血性直肠炎的疗效观察

目的:放射性出血性直肠炎是盆腔恶性肿瘤放疗后的常见并发症,本研究旨在探索电子结肠镜下4%甲醛溶液治疗宫颈癌放疗后放射性出血性直肠炎的疗效。方法:选取我院于2012年5月至2014年5月确诊为宫颈癌并于接受放射治疗后出现放射性出血性直肠炎的患者104例,随机平均分为甲醛治疗组(52例)和对照组(52例),前组给予电子结肠镜下4%甲醛溶液局部治疗,后者给予思密达(3g)、地塞米松(5mg)和庆大霉素(8万单位)混合液保留灌肠治疗,比较该方法与传统方法治疗效果的差异。结果:甲醛组共治愈患者24例(46.2%),显效21例(40.4%),好转4例(7.7%),无效3例(5.7%),总有效率94.3%,未发现直肠溃疡和穿孔;对照组共治愈患者18例(34.6%),显效17例(32.7%),好转6例(11.5%),无效11例(21.2%),总有效率78.8%,甲醛组的疗效明显高于对照组(χ2=7.84,P<0.01)。结论:电子结肠镜下4%甲醛稀释液是治疗宫颈癌放射性出血性直肠炎的有效方法。