Collisional effects on the current-filamentation instability in a dense plasma

The collisional current-filamentation instability (CFI) is studied for a nonrelativistic electron beam penetrating an infinite uniform plasma. It is analytically shown that the CFI is driven by the drift-anisotropy rather than the classical anisotropy of the beam and the background plasma. Therefore, collisional effects can either attenuate or enhance the CFI depending on the drift-anisotropy of the beam-plasma system. Numerical results are given for some typical parameters, which show that collisional effects cannot stabilize but enhance the CFI in a dense plasma. Thus, the CFI may play a dominant role in the fast electron transport and deposition relevant to the fast ignition scenario (FIS).     

正常金属-分子量子点-超导耦合系统的介观输运研究

运用非平衡格林函数理论、正则变换以及BCS平均场理论研究了正常金属-分子量子点-超导耦合系统（N-MQD-S）的介观输运,得到了系统的电流公式并选择适当的参数进行了数值计算。数值计算结果表明：电声子耦合强度 与线宽函数 对系统的输运行为有较大影响。当 增大时,由声子辅助隧穿所产生的共振峰将高于分子量子点自身能级产生的共振峰;当线宽函数 增大时,在Andreev反射共振峰的两侧将出现新的边峰。     

Laser in micro and nanoprocessing of diamond materials

Basic processing operations will be presented. These include diamond polishing and shaping, production of conductive pathways, micro‐ and nanostructures on the diamond surface, such as diffractive optical elements. The possibility to laser produce conductive and hollow structures in the diamond bulk, including curved elements, will be demonstrated. Finally, the techniques of laser assisted diamond CVD, that allow production of smooth or selective‐area grown films will be presented     

双势阱中冷原子的关联隧穿

研究了在不同的相互作用和隧穿耦合强度比值情况下双势阱中冷原子的隧穿现象.两格点Bose-Hubbard模型不能完全解释实验.为此,对此模型做了高阶修正.取双势阱的基态和第一激发态作基矢,写出哈密顿量的表示,解释了用两格点Bose-Hubbard模型分析实验时参数不能定量符合的原因.另外,通过计算两阱中原子纠缠度的变化,结合三态上原子布居数分布,直观描述了整个隧穿过程.     

Hyperfine Spectroscopy with Nuclear Resonant Scattering of Synchrotron Radiation

Since its observation in 1985 nuclear resonant scattering of synchrotron radiation has become an excellent tool to study hyperfine interactions in solids. It combines the advantages of both local probe experiments and scattering techniques and gives valuable information on magnetic and electronic structures in case of NFS experiments. Experiments benefit from the outstanding beam quality of 3rd generation synchrotron radiation sources, as the small beam size and divergence. This revised version was published online in August 2006 with corrections to the Cover Date.     

δ势垒对多臂量子环中持续电流的影响

提出了中臂弯曲的多臂量子环模型,且是上臂最短和下臂最长的不等臂量子环.研究发现：总磁通为零时,持续电流随半导体环增大发生非周期性振荡,并与电极的磁矩方向及隧穿电子的自旋方向相关,下臂因为最长而获得最小的平均持续电流.AB磁通增强时,持续电流会发生周期性振荡,各臂之间明显出现相互制约的现象.各臂持续电流之间的差异与臂长和磁通分布相关,Rashba自旋轨道耦合具有改变持续电流相位和相位差的效应.在一定条件下,两种波函数所对应的持续电流是可分离的.     

核物质状态方程中动量相关作用可能的探针

研究了动量相关作用对于中子-质子比动能谱rb(Ek)的效应,发现rb(Ek)灵敏的依赖于动量相关作用而弱的依赖于介质中核子-核子碰撞截面和对称势.因此rb(Ek)是提取重离子碰撞中动量相关作用信息的可能探针.同时,对于丰中子弹核和相同质量稳定弹核在相同入射道条件下,丰中子碰撞系统明显加强了动量相关作用对rb(Ek)的效应.故两个碰撞系统rb(Ek)结果的比较为在重离子碰撞中提取动量相关作用的知识提供了另一个重要的判据。     

Deeply bound kaonic states in nuclei

Using a new phenomenological KN interaction which reproduces Λ(1405) as an I=0 bound state of KN, we have investigated K^－－³ He(T=0) and K^－－⁴ He(T=1/2) within the framework of the Brueckner-Hartree-Fock(BHF) theory. Our calculations show that the above kaonic nuclear systems are both deeply bound. The binding energy B_K－ is 124.4 MeV(94.1 MeV) and the width Γ is 11.8 MeV(25.8 MeV) for K^－－³He(T=0) (K^－－⁴He(T=1/2)).     

He-BH碰撞体系微分截面的理论计算

用公认精确的密耦近似方法计算了入射能量从25至150 meV时,He原子与基态BH分子碰撞的弹性微分截面、非弹性微分截面和总微分截面,进一步讨论了微分截面的变化趋势及特征.计算结果表明：He-BH碰撞体系的总微分截面具有原子与双原子分子散射的一般规律和特征;随着入射能量的增加,低转动激发态-态微分截面在大角区的散射振荡现象会更加明显. 关键词： He-BH复合物 相互作用势 密耦近似 微分截面