Optical Interface Phonon in Graded Quantum Well Structures

The behaviour of optical interface phonon is investigated first for the graded quantum well of Ga_(l-x)Al_(x)As in the dielectric continuum model.It is found that the behaviour of interface phonon modes is quite different from that in square quantum well structure.The dispersions of the interface modes are sensitive to the gradient of the graded quantum well structure,and the symmetry of modes can be changed greatly,which is important for phonon-related phenomena.

Electronic Structure of C_(70) Within the Tight-Binding Approximation

The electronic structure of C_(70) molecule with D5h symmetry has been studied using a simple tight-binding approximation.Comparing the results with those of local-density approximation calculation and experiment,we have determined the hopping matrix element.We have also compared the electronic structure and charge density over cluster of C_(70) with the results of ellipsoid model,and found the angular momentum and magnetic quantum number(1 and m)of each bunch and level.

Electronic Structure of CBN Ball Within Tight-Binding Approximat ion

Using a tight-binding approximation,we have calculated the electronic structure of the suggested CBN ball created from buckyball C_(60) in which 48 carbon atoms are replaced with 24 boron atoms and 24 nitrogen atoms.

Electronic Structure of (lll)-Oriented St rained-Layer SiGe Superlattice

Using the first-principle self-consistent linear-muffin-tin-orbital method within the local density approximation,band structure of(111)-oriented strained-layer SiGe superlattice is studied.Three different ordered arrangements of atom layers(Si-Ge■Si-Ge Si-Si■Ge-Ge and Si■Si-Ge■Ge)are considered.Calculated results indicate that(111)-oriented SiGe strained layer superlattices are semiconductive,with a band gap about 1.OeV.The first two superlattices are indirect band gap semiconductors,and the third one(Si■Si-Ge■Ge)is a direct band gap semiconductor.The influence of strain on the band structure is also investigated.

甘肃省白银市2019-2020年药械化“四项监测”报告回顾分析

目的分析白银市2019-2020年药械化"四项监测"发生的规律与特点,促进公众合理用药用械用妆。方法回顾性分析白银市2019-2020年上报至国家不良反应监测中心的4791例不良反应报告。结果4791例不良反应报告中,药品不良反应占比最大,2019、2020年分别占34.69%、36.97%;医疗器械不良事件次之,2019、2020年分别占9.58%、10.02%;化妆品不良反应和药物滥用占比最小,2019、2020年化妆品不良反应分别占2.50%、2.71%,药物滥用分别占2.88%、0.65%。结论应进一步提升白银市药械化"四项监测"能力。白银市药械化不良反应/事件的发生受多种因素影响,需引起高度重视。