一维势垒散射中粒子的概率分布

利用数值计算方法研究了E>U0、0相似文献   

同轴式DBD分解NO/N_2混合气的光谱研究

本文建立了大气压介质阻挡放电发射光谱测量系统,测得NO/N_2体系的等离子体发射光谱。利用Q-V Lissajous图形法对反应器电学参量进行测试,研究激励电压峰峰值V_（P-P）对NO、N_2各激发态物种光谱强度的影响。实验结果表明：低温等离子体产生的高能电子可有效作用于NO、N-2分子,产生NO（A~2∑~＋→X~...     

介质阻挡放电跃变升压模式下靶波斑图研究

在大气压氩气介质阻挡放电中,首次通过跃变外加电压得到了稳定的靶波斑图.实验分别研究了跃变再缓变和直接跃变升压模式下靶波斑图的稳定性和波长选择.研究发现,跃变再缓变升压之后得到的靶波斑图不稳定,其与螺旋波相互转换.在这种转换中,靶波每次出现的时间为几十毫秒.直接跃变升压得到的靶波斑图稳定性明显增强,其稳定时间通常为5 min以上.比较不同升压模式下靶波斑图的波长,发现直接跃变升压模式下波长随电压升高减小较快.综上表明,升压模式对靶波斑图的稳定性和波长都有影响. 关键词： 介质阻挡放电 靶波斑图 跃变升压 缓变升压     

线度和势垒宽度对球状纳米系统电子散射截面的影响

在有效质量近似和球形方形势模型下,计算了开放型球状纳米系统电子散射截面及电子按能量的概率分布,探讨了线度、势垒宽度对电子散射截面和共振能量以及共振宽度的影响.结果表明:电子的散射截面随能量的分布曲线有一极大值和极小值,而且电子能量的概率分布曲线的极大值位置总是介于散射截面分布曲线的极大值与极小值的能量位置之间;散射截面随内核半径r₀的增大而增大,而且散射截面分布曲线随r₀的增大由较平滑变得较尖锐;散射截面随势垒宽度Δ的增大而增大,但在Δ＝1.4a_CdS–1.7a_CdS的范围内,变化出现异常,在Δ=1.6a_CdS时散射截面出现极小;电子共振能量E_l 随Δ的变化与电子所处状态有关,而电子共振宽度Γ_l随Δ的增大而减小;不论Δ取何值, E_l和Γ_l都满足能量和时间的测不准关系. 关键词： 球状纳米系统 势垒宽度 电子散射截面 电子概率分布     

A boundary element method for the calculation of noise barrier insertion loss in the presence of atmospheric turbulence

Atmospheric turbulence is an important factor that limits the amount of attenuation a barrier can provide in the outdoor environment. It is therefore important to develop a reliable method to predict its effect on barrier performance. The boundary element method (BEM) has been shown to be a very effective technique for predicting barrier insertion loss in the absence of turbulence. This paper develops a simple and efficient modification of the BEM formulation to predict the insertion loss of a barrier in the presence of atmospheric turbulence. The modification is based on two alternative methods: (1) random realisations of log-amplitude and phase fluctuations of boundary sources and (2) de-correlation of source coherence using the mutual coherence function (MCF). An investigation into the behaviours of these two methods is carried out and simplified forms of the methods developed. Some systematic differences between the predictions from the methods are found. When incorporated into the BEM formulation, the method of random realisations and the method of MCF de-correlation provide predictions that agree well with predictions by the parabolic equation method and by the scattering cross-section method on a variety of thin barrier configurations.     

Concentric-ring structures in an atmospheric pressure helium dielectric barrier discharge

This paper performs a numerical simulation of concentric-ring discharge structures within the scope of a two-dimensional diffusion--drift model at atmospheric pressure between two parallel circular electrodes covered with thin dielectric layers. With a relative high frequency the discharge structures present different appearances of ring structures within different radii in time due to the evolvement of the filaments. The spontaneous electron density distributions help understanding the formation and development of self-organized discharge structures. During a cycle the electron avalanches are triggered by the electric field strengthened by the feeding voltage and the residual charged particles on the barrier surface deposited in the previous discharges. The accumulation of charges is shown to play a dominant role in the generation and annihilation of the discharge structures. Besides, the rings split and unify to bring and annihilate rings which form a new discharge structure.     

Erratum to "Quantum compact model for thin-body double-gate Schottky barrier MOSFETs"

<正>The statement for the third paragraph of the right column of page 3079 (Chinese Physics B, 2008, Vol. 17,No. 8, pp. 3077-3082 )[1]is inappropriate. This paragraph should be restated as follows.     

磁通量子比特qubit信号强度随势垒偏置电压的变化

在20mK极低温下,测量了超导磁通量子比特的环流方向,并测到量子比特(qubit)信号.通过改变磁通量子比特的势垒高度,得到qubit信号强度随势垒高度的变化的实验数据并建立理论模型解释了实验现象.     

The influence and explanation of fringing-induced barrier lowering on sub-100 nm MOSFETs with high-k gate dielectrics

The fringing-induced barrier lowering(FIBL) effect of sub-100 nm MOSFETs with high-k gate dielectrics is investigated using a two-dimensional device simulator.An equivalent capacitance theory is proposed to explain the physics mechanism of the FIBL effect.The FIBL effect is enhanced and the short channel performance is degraded with increasing capacitance.Based on equivalent capacitance theory,the influences of channel length,junction depth,gate/lightly doped drain(LDD) overlap length,spacer material and spacer width on FIBL is thoroughly investigated.A stack gate dielectric is presented to suppress the FIBL effect.     

Coverage Dependence of Growth Mode in Heteroepitaxy of Ni on Cu（100） Surface

A realistic kinetic Monte Carlo （KMC） simulation model with physical parameters is developed, which well reproduces the heteroepitaxial growth of multilayered Ni thin film on Cu（100） surfaces at room temperature. The effects of mass transport between interlayers and edge diffusion of atoms along the islands are included in the simulation model, and the surface roughness and the layer distribution versus total coverage are calculated. Speeially, the simulation model reveals the transition of growth mode with coverage and the difference between the Ni heteroepitaxy on Cu（100） and the Ni homoepitaxy on Ni（100）. Through comparison of KMC simulation with the real scanning tunneling microscopy （STM） experiments, the Ehrlich-Schwoebel （ES） barrier Ees is estimated to be 0.18±0.02 eV for Ni/Cu（100） system while 0.28 eV for Ni/Ni（100）. The simulation also shows that the growth mode depends strongly on the thickness of thin film and the surface temperature, and the critical thickness of growth mode transition is dependent on the growth condition such as surface temperature and deposition flux as well.