硅表面清洗对热氧化13nm SiO_2可靠性的影响

实验研究表明热生长13nm薄SiO_2的可靠性同氧化前硅表面清洗处理方法有很关系。氧化前稀HF酸及HF/乙醇漂洗不会提高热氧化薄SiO_2的可靠性；氧化前用NH_4OH/H_2O_2/H_2O(0.05:2:5)溶液清洗形成化学预氧化层对提高薄SiO_2可靠性很有效；用H_2SO_4/H_2O_2(3:1)溶液清洗形成预氧化层的改善作用也较明显，在之间增加比例为0.05:2:5或1:2:5的NH_4OH/H_2O_2/H_2O溶液清洗和稀HF酸漂洗效果更好。另外，薄栅介质抗电离辐射性能和抗热电子损伤能力同氧化前形成化学预氧化层的清洗液种类关系不大，电离辐射对薄栅介质击穿特性的影响不明显。

Photoemission evidence for dilute k-doped phase KxC（60） with x<0.2

于2010-11-23批量导入

Electronic characteristics of InAs self-assembled quantum dots

Deep-level transient spectroscopy and photoluminescence studies have been carried out on structures containing self-assembled InAs quantum dots formed in GaAs matrices. The use of n- and p-type GaAs matrices allows us to study separately electron and hole levels in the quantum dots by the deep-level transient spectroscopy technique. From analysis of deep-level transient spectroscopy measurements it follows that the quantum dots have electron levels 130 meV below the bottom of the GaAs conduction band and heavy-hole levels at 90 meV above the top of the GaAs valence band. Combining with the photoluminescence results, the band structures of InAs and GaAs have been determined. (C) 2000 Elsevier Science B.V. All rights reserved.

PREDICTION OF VORTEX-INDUCED VIBRATION OF FLEXIBLE RISER USING AN IMPROVED WAKE-OSCILLATOR MODEL

Based on improving the wake-oscillator model, an analytical model for vortex-induced vibration (VIV) of flexible riser under non-uniform current is presented, in which the variation of added mass at lock-in and the nonlinear relationship between amplitude of response and reduced velocity are considered. By means of empirical formula combining iteration computation, the improved analytical model can be conveniently programmed into computer code with simpler and faster computation process than CFD so as to be suitable to application of practical engineering. This model is validated by comparing with experimental result and numerical simulation. Our results show that the improved model can predict VIV response and lock-in region more accurately. At last, illustrative examples are given in which the amplitude of response of flexible riser experiencing VIV under action of non-uniform current is calculated and effects of riser tension and flow distribution along span of riser are explored. It is demonstrated that with the variation of tension and flow distribution, lock-in region of mode behaves in different way, and thus the final response is a synthesis of response of locked modes.

超重核研究谱仪的RFQ冷却聚束器RFQ1L

介绍了超重核研究谱仪中RFQ冷却聚束器RFQ1L的结构和运用SIMION程序对离子的冷却、聚束、引出和撇气过程的模拟情况。模拟显示:通过仔细选择工作点就完全可以把经过充气反冲质量分离器分离后的低品质束流转化为斑点小、发射度小和能量单一的高品质束流,为紧接其后的磁铁和激光高效率分析提供条件。

离子束生物效应及应用中值得研究的几个问题

重离子束生物效应及重离子束在生命科学中的应用研究,在国内外物理学与生命科学领域中得到了广泛的开展,但对出现的一些现象还没有深刻地揭露其本质,作出机理性解释。为了深入研究,本文提出一些值得研究的问题供参考,如:重离子径迹结构及能量沉积分布模型,DNA辐射敏感位点,质量沉积-分子改造,直接作用与间接作用,放射性核束的应用等。

高电荷态离子~(207)Pb~(36+)与金属Nb表面作用产生的二次离子产额

本文报道了利用兰州重离子加速器国家实验室的ECR离子源引出的高电荷态离子207Pb36+入射到金属Nb表面产生的二次离子的实验测量结果.实验发现,二次离子产额Y随入射初动能Ek的增加有先增加后减小的关系,在初动能为576 keV时二次离子产额达到最大.通过对实验点做高斯拟合发现,曲线峰值对应的入射初动能为602 keV.分析表明,这是势能沉积作用与线性级联碰撞过程协同作用的结果.高电荷态离子本身携带的高势能沉积在靶表面引起势能溅射,促进了二次离子的发射;而主导二次离子溅射的过程是动能溅射,它与靶表面的动量沉积(核能损)过程密切相关.