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场发射枪低压扫描电镜的电子光学设计
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作者 西门纪业 P.S.D.Lin +1 位作者 J.B.Pawley M.Schippert 《电子显微学报》 CAS CSCD 1993年第5期428-432,共5页
本文讨论了场发射枪低压扫描电镜的电子光学设计,包括用于低压条件下两种型式的磁透镜的优化设计,以及对于磁透镜和二次电子接收器的整体联合设计。计算结果和初步实验表明,本文设计的低压扫描电镜可以达到2.5~3.0纳米的分辨率,它与电... 本文讨论了场发射枪低压扫描电镜的电子光学设计,包括用于低压条件下两种型式的磁透镜的优化设计,以及对于磁透镜和二次电子接收器的整体联合设计。计算结果和初步实验表明,本文设计的低压扫描电镜可以达到2.5~3.0纳米的分辨率,它与电子光学理论预期值基本符合。低压扫电镜的工作电压一般认为是在0.75kV到3~5kV范围内。其主要优点为:可以减小试样的荷电,直接观察非导体试样而不用涂覆,并减少图形的假象;穿透深度浅,提高图象的立体感和衬度;对于半导体、塑料、高分子和生物试样还可以减少试样的辐射损伤。因此低压扫描电镜成为具有特色的电镜分析工具。近年来国外正在兴起低压扫描电镜的研制、开发和应用(例如,美国的AM-RAY公司和日本的日立公司等)。1991—1993年,我们从事了美国国家科学基金研究项目,设计成功低压扫描电镜及其电子接收器系统。现已由美国AMRAY公司研制成功。本文将讨论这个具有场发射枪的低压扫描电镜的电子光学设计。 展开更多
关键词 低压扫描电镜 扫描电镜 磁透镜 电子光学设计
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Effects of strain rate and temperature on microstructure and texture for AZ31 during uniaxial compression
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作者 辛仁龙 汪炳叔 +2 位作者 周正 黄光杰 刘庆 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期594-598,共5页
In order to investigate the effects of strain rate and temperature on the microstructure and texture evolution during warm deformation of wrought Mg alloy,AZ31 extruded rods were cut into cylinder samples with the dim... In order to investigate the effects of strain rate and temperature on the microstructure and texture evolution during warm deformation of wrought Mg alloy,AZ31 extruded rods were cut into cylinder samples with the dimension of d8 mm×12 mm.The samples were compressed using a Gleeble 1500D thermo-mechanical simulation machine at various strain rates(0.001,0.01,0.1,1 and 5 s- 1)and various temperatures(300,350,400 and 450℃).The microstructure and texture of the compressed samples at the same strain under different deformation conditions were studied and compared by electron backscatter diffraction(EBSD)in scanning electron microscope(SEM).The results show that the size of recrystallized grains in the deformed samples generally increases with the decrease of strain rate and the increase of temperature.After 50%reduction,most basal planes are aligned perpendicular to the compression direction at relatively high strain rate(>0.01 s- 1)or low temperature(<350℃).The optimized strain rate is 0.1 s- 1for uniaxial compression at 300℃,which produces about 80%of small grains(<5μm). 展开更多
关键词 magnesium alloy electron backscatter diffraction dynamic recrystallization microstructure TEXTURE
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