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3篇 您的检索式:作者名="R.Gray"
    题名 作者 年代 出处 被引量
1EMP control and characterization on high-power laser systems显示文摘Giant electromagnetic pulses(EMP) generated during the interaction of high-power lasers with solid targets can seriously degrade electrical measurements and equipment. EMP emission is caused by the acceleration of hot electrons inside the target, which produce radiation across a wide band from DC to terahertz frequencies. Improved understanding and control of EMP is vital as we enter a new era of high repetition rate, high intensity lasers(e.g. the Extreme Light Infrastructure).We present recent data from the VULCAN laser facility that demonstrates how EMP can be readily and effectively reduced. Characterization of the EMP was achieved using B-dot and D-dot probes that took measurements for a range of different target and laser parameters. We demonstrate that target stalk geometry, material composition, geodesic path length and foil surface area can all play a significant role in the reduction of EMP. A combination of electromagnetic wave and 3 D particle-in-cell simulations is used to inform our conclusions about the effects of stalk geometry on EMP,providing an opportunity for comparison with existing charge separation models.P.Bradford N.C.Woolsey G.G.Scott G.Liao H.Liu Y.Zhang B.Zhu C.Armstrong S.Astbury C.Brenner P.Brummitt F.Consoli I.East R.Gray D.Haddock E Huggard E J.R.Jones E.Montgomery I.Musgrave E Oliveira D.R.Rusby C.Spindloe B.Summers E.Zemaityte Z.Zhang Y.Li P.McKenna D.Neely 2018High Power Laser Science and Engineering2018,6,2:3
2Accuracy of radiological staging in identifying high‐risk colon cancer patients suitable for neoadjuvant chemotherapy: a multicentre experience显示文摘S.Dighe I.Swift L.Magill K.Handley R.Gray P.Quirke D.Morton M.Seymour B.Warren G.Brown 2012Colorectal Disease2012,,:2
3金属固化:从单晶体到微晶体显示文摘控制铸件的固化和冷却速度会大大影响合金的宏观结构与微观结构及其最终机械特性。根据期望要得到的结果,金属可以极其缓慢地也可几乎瞬时地予以冷却。要制造单晶体,金属得在模具中以每秒10^(-3)~10^(-1)度的冷却速度予以固化。制造出来的铸件与涡轮叶片的实际形状几乎相同。反之,以每秒10~6度的速度快速固化,则得到粉状或带状物。这些材料晶粒极细,并且合金元素和强化相位分布均匀。单晶体超合金作为航天飞机主发动机高压涡轮泵的涡轮叶片正在鉴定之中。虽然这些叶片将在比飞机涡轮低的稳态温度环境中工作,但是它们经受的疲劳状况势必要严重得多。国家航空航天局的刘易斯研究中心和马歇尔研究中心都在研究如何改善超合金的抗疲劳性以及如何更好地了解氢对超合金的有害影响。Hugh R.Gray 林志信 1989世界科学1989,11,1:0
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