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简要描述了慢速(v<vBohr)高电荷态离子与表面相互作用过程中的电子、光子发射过程.介绍了用于高电荷态离子与表面作用实验研究的目前兰州近物所的实验装置和取得的一些初步实验结果. 相似文献
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126Xeq+轰击Al表面产生的原子和离子光谱线 总被引:1,自引:1,他引:0
报道了高电荷态离子^126Xe^q (6≤q≤30)入射到固体Al表面产生的200~1000nm波段的发射光谱的实验结果。实验表明,在弱束流(nA量级)高电荷态的情况下,通过入射离子与固体靶的相互作用可有效地产生原子和离子的复杂组态间跃迁所形成的可见光波段的特征谱线,而且当入射离子的电荷剥离数超过一临界值后(对Al,q=26),谱线相对强度突然显著增强。根据经典过垒模型COB(The classic over-barrier model),在入射离子的动能较小(~1keV/u)的条件下.高电荷态离子与表面相互作用过程中电子的俘获或转移起着非常重要的作用,通过提高入射离子的电荷态可增强入射离子俘获电子的能力.显著增强激发粒子的光谱线的强度。 相似文献
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建成了兰州重离子加速器国家实验室320KV—ECR离子源表面物理实验终端,阐述了该实验终端的关键技术参数,描述了即将开展的高电荷态离子与表面相互作用的物理研究工作及其研究意义. 相似文献
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论述了高电荷态离子与表面相互作用的过程 ,说明了发射电子、发射光子、负离子、中性粒子、正离子的散射和发射的物理机理以及应用前景 .介绍了在兰州重离子国家实验室ECR源建立高电荷态离子与表面相互作用的原子物理平台的重要意义和将要开展的工作.The interaction between highly charged ions and surface is investigated, the mechanisms for emissions of electrons, photons and scattered neutral particles, negative and positive ions are reviewed. We report a new atomic physics station in ECR and our work plan. 相似文献
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报道了利用兰州重离子加速器国家实验室ECR源引出的高电荷态离子207Pbq+(24≤q≤36)入射到Si(110)表面产生的电子发射的实验测量结果.结果表明,高电荷态离子与固体表面相互作用产生的电子发射产额Y与入射离子的电荷态q、入射角度ψ和入射能量E都有很强的关联.首次发现,电子发射产额Y与入射角度ψ间有接近1/tanψ的关系.理论分析认为,这些过程与基于经典过垒模型的势能电子发射过程密切相关.
关键词:
高电荷态离子
经典过垒模型
电子发射产额 相似文献
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报道了利用兰州重离子加速器国家实验室ECR源引出的高电荷态离子207Pbq+(24≤q≤36)入射到Si(110)表面产生的电子发射的实验测量结果.结果表明,高电荷态离子与固体表面相互作用产生的电子发射产额Y与入射离子的电荷态q、入射角度ψ和入射能量E都有很强的关联.首次发现,电子发射产额Y与入射角度ψ间有接近1/tanψ的关系.理论分析认为,这些过程与基于经典过垒模型的势能电子发射过程密切相关. 相似文献
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This paper describes ab initio electronic structure calculations on the planar transition states of 2-chloropropene leading to HCI elimination in the ground electronic state to form either propyne or allene as the cofragment. The calculations provide optimized geometries of the transition states for these two reaction channels, together with vibrational frequencies, barrier heights, and reaction endothermicities. The calculated barrier heights for the two distinct four-centre HCI elimination transition states, one leading to HCI and propyne and the other leading to HCI and allene, are 72.5kcalmol?1 (77.8kcalmol?1 without zero-point correction) and 73.2kcalmol?1 (78.7kcalmol?1) at the MP2/6-311G(d, p) level, 71.Okcalmol?1 (76.3kcalmol?1) and 70.5kcalmol?1 (76.0kcalmol?1) at the QCISD(T)/6-311 +G(d, p)//MP2/6-311G(d, p) level, and 66.9kcalmol?1 (71.7kcalmol?1) and 67.3kcalmol?1 (72.1kcalmol1) at the G3//B3LYP level of theory. Calculated harmonic vibrational frequencies at the B3LYP/6-31G(d) level along with transition state barrier heights from the G3//B3LYP level of theory are used to obtain RRKM reaction rate constants for each transition state, which determine the branching ratio between the two HCI elimination channels. Even at internal energies well above both HCI elimination barriers, the HCI elimination leading to propyne is strongly favoured. The smaller rate constant for the HCI elimination leading to allene can be attributed to the strong hindrance of the methyl rotor in the corresponding transition state. 相似文献
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Zoran Andelkovic Gerhard Birkl Svetlana Fedotova Volker Hannen Frank Herfurth Kristian König Nikita Kotovskiy Bernhard Maaß Jonas Vollbrecht Tobias Murböck Dennis Neidherr Wilfried Nörtershäuser Stefan Schmidt Manuel Vogel Gleb Vorobjev Christian Weinheimer 《Hyperfine Interactions》2015,231(1-3):37-44
Heavy few-electron ions are relatively simple systems in terms of electron structure and offer unique opportunities to conduct experiments under extremely large electromagnetic fields that exist around their nuclei. However, the preparation of highly charged ions (HCI) has remained the major challenge for experiments. As an extension of the existing GSI accelerator facility, the HITRAP facility was conceived as a multi-stage decelerator for HCI produced at high velocity. It is designed to prepare bunches of around 105 HCI and to deliver them at low energies to various experiments. One of these experiments is SpecTrap, aiming for laser spectroscopy of trapped, cold HCI. We present the latest results on deceleration of ions in a radio-frequency quadrupole, synchrotron cooling of electrons in a trap as a preparation step for the prospective electron cooling of the HCI decelerated in HITRAP, as well as laser cooling of singly charged Mg ions for sympathetic cooling of HCI in SpecTrap. 相似文献
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随着场效应晶体管(MOSFET)器件尺寸的进一步缩小和器件新结构的引入, 学术界和工业界对器件中热载流子注入(hot carrier injections, HCI)所引起的可靠性问题日益关注. 本文研究了超短沟道长度(L=30–150 nm)绝缘层上硅(silicon on insulator, SOI)场效应晶体管在HCI应力下的电学性能退化机理. 研究结果表明, 在超短沟道情况下, HCI 应力导致的退化随着沟道长度变小而减轻. 通过研究不同栅长器件的恢复特性可以看出, 该现象是由于随着沟道长度的减小, HCI应力下偏压温度不稳定性效应所占比例变大而导致的. 此外, 本文关于SOI器件中HCI应力导致的退化和器件栅长关系的结果与最近报道的鳍式场效晶体管(FinFET)中的结果相反. 因此, 在超短沟道情况下, SOI平面MOSFET器件有可能具有比FinFET器件更好的HCI可靠性. 相似文献
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Wilfried N?rtersh?user 《Hyperfine Interactions》2011,199(1-3):131-140
An overview on laser spectroscopic work on highly charged ions (HCI) currently performed or in preparation at GSI is given. This includes laser spectroscopy on HCI in ion traps at the HITRAP facility and at the experimental storage ring (ESR). 相似文献
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原子吸收光谱法测定鸡蛋中营养元素的前处理方法研究 总被引:8,自引:1,他引:7
本文分别采用0.1mol·L-1盐酸、6mol·L-1盐酸、pH7.01mol·L-1NH4Ac振荡提取及6mol·L-1盐酸煮沸法测定了鸡蛋中K、Na、Mg、Ca、Zn、Fe、Mn、Cu八种元素,并与经典前处理方法即现在普遍采用的浓硝酸-高氯酸全消化法及干灰法进行比较,结果表明,对于大量元素K、Na、Mg几种提取方法与经典法接近,回收率达90%~115%;微量元素Zn、Mn、Fe也可分别用pH7.01mol·L-1NH4Ac,0.1mol·L-1盐酸、6mol·L-1盐酸振荡提取,回收率在100%~115%之间,Cu则可用6mol·L-1盐酸煮沸法测定,回收率较理想。而Ca这几种方法提取结果均不理想,主要因增感作用,造成结果偏高。经典干灰化结果偏低,灰化温度达450℃,即可造成多种元素损失,且繁琐费时。本文采用的几种提取方法简单、快速,结果准确性、精度可达到分析要求。 相似文献
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基于生物电的人-机交互(HCI)技术作为特殊场景下常规人-机交互方法的一种补充,具有非常广阔的应用前景。为了解决基于生物电的HCI系统中多用户通信问题,文章设计并实现了一种基于ZigBee技术的信息交互系统。该系统主要由ZigBee无线通信模块、信息生成/处理模块、串口通信模块三部分组成,用以实现多用户间使用眼电信号(EOG)进行无线信息交互。在实验室环境下,眼电信号有效检出率98.2%,传输距离在无遮挡、无路由的情况下可达到70m。实验结果表明该系统具有识别率高、稳定性好、配置简单、使用方便等优点,具有较强的实际应用价值。 相似文献
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Jinghao Zhao Hang Zhou Jiangwei Cui Qiwen Zheng Ying Wei Shanxue Xi 《辐射效应与固体损伤》2013,168(7-8):606-616
ABSTRACTThe authors perform gamma ray irradiation and hot carrier stress on RH H-Gate PD (partially depleted) SOI NMOSFETs as the experimental group and commercial strip-shaped gate PD SOI NMOSFETs as the control group. They analyse HCI degradation in samples and conclude that radiation could enhance HCI degradation in RH H-gate samples. Moreover, the mechanism is explained as the coupling effect between the front gate and back gate caused by TID radiation-induced trap charges in the buried oxide. 相似文献
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Highly charged ions (HCIs) have huge potential energy due to their high charge state. When a HCI reaches a solid surface, its potential energy is released immediately on the surface to cause a nano-scale defect. Thus, HCIs are expected to be useful for solid-surface modifications on the nano-scale. We investigate the defects on a highly oriented pyrolytic graphite (HOPG) surface induced by slow highly charged Ar^q+ ions with impact energy of 20-2000qeV with scanning probe microscopy (SPM). In order to clarify the role of kinetic and potential energies in surface modification, the nano-defects are characterized in lateral size and height corresponding to the kinetic energy and charge state of the HCIs. Both the potential energy and kinetic energy of the ions may influence the size of nano-defect. Since potential energy increases dramatically with increasing charge state, the potential energy effect is expected to be much larger than the kinetic energy effect in the case of extremely high charge states. This implies that pure surface modification on the nano-scale could be carried out by slow highly charged ions. The mean size of nano-defect region could also be controlled by selecting the charge state and kinetic energy of HCI. 相似文献
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M. Froese C. Champagne J. R. Crespo López-Urrutia S. Epp G. Gwinner A. Lapierre J. Pfister G. Sikler J. Ullrich J. Dilling 《Hyperfine Interactions》2006,173(1-3):85-92
The precision of atomic mass measurements in a Penning trap is directly proportional to the charge state q of the ion and,
hence, can be increased by using highly charged ions (HCI). For this reason, charge breeding with an electron beam ion trap
(EBIT) is employed at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) on-line facility in Vancouver, Canada. By bombarding
the injected and trapped singly charged ions with an intense beam of electrons, the charge state of the ions is rapidly increased
inside the EBIT. To be compatible with the on-line requirements of short-lived isotopes, very high electron beam current densities
are needed. The TITAN EBIT includes a 6 Tesla superconducting magnet and is designed to have electron beam currents and energies
of up to 5 A and 60 keV, respectively. Once operational at full capacity, most species can be bred into a He-like configuration
within tens of ms. Subsequently, the HCI are extracted, pass a Wien filter to reduce isobaric contamination, are cooled, and
injected into a precision Penning trap for mass measurement. We will present the first results and current status of the TITAN
EBIT, which has recently been moved to TRIUMF after assembly and commissioning at the Max-Planck-Institute (MPI) for Nuclear
Physics in Heidelberg, Germany. 相似文献