禁带

The electromagnetic propagation process of a Gaussian pulse through an unmagnetized plasma photonic crystal is investigated.

它具有一定的光子能带结构，一定频率的光不能在晶体中传播，从而产生了光子禁带。

The frequency dispersion and variation of group velocity with frequency are also calculated.

分析表明，两种界面上的非线性TE表面波均存在频率通带和禁带，且带宽是传播功率的函数。

XRD,X-ray EDS analysis,AFM and Fourier transform infrared spectroscopy were employed to characterize PbSe thin films. The results show that all of the films were heteromorphy and the growth temperature has effect to the diffract peaks of the films. The contents of PbSe thin films by PLD consisted with the targets,and realizing thin films deposited with same constitutes; the films had rather flatness surface and compact structure; the peak-to-tail roughness of PbSe thin films surfaces was less than 200nm;they had sensitivity to light of a specified wavelength and obvious absorption edge at 5μm corresponding to band-gap width of PbSe thin films;light of wavelength less than 5μm was strongly absorbed.

通过脉冲激光沉积法在Si(111)和SiO2玻璃基片上制备了PbSe薄膜。X射线衍射、X射线能谱、原子力显微镜、傅里叶变换红外光谱仪测试结果表明：所有制备的薄膜都为多晶薄膜，发现薄膜生长温度对薄膜衍射峰有一定影响；PLD法制备的薄膜的成分与靶材的基本一致，实现了同组分沉积；所有薄膜表面比较平滑，表面不平整度小于200nm，结构比较致密；PbSe薄膜对红外光具有敏感的响应特性；在波长为5μm处存在有明显的吸收边，此吸收边对应于直接带隙PbSe材料的禁带宽度；对应于波长小于5μm的红外光，PbSe薄膜存在有明显的强吸收。

In recent years, SiC FET power transistor and GaN high electron movability power transistor represent the third generation semiconductor-wide bandgap semiconductor power devices, have advantages of high breakdown voltage, high power density, as well as high output power, high operation efficiency, high operation frequency, wide instant aneous bandwidth, operation in high temperature environment and strong ability of resisting radiation.

近年来以SiC场效应功率晶体管和GaN高电子迁移率功率晶体管为代表的第三代半导体－宽禁带半导体功率器件具有击穿电压高、功率密度高、输出功率高、工作效率高、工作频率高、瞬时带宽宽、适合在高温环境下工作和抗辐射能力强等优点。

ZnO is a n-type semiconductor with wide band gap of 3.2 eV.

ZnO是一种n型的宽禁带半导体材料，带隙3.2 eV。

Zinc oxide is an n-type direct band-gap semiconductor material. Due to the large exciton binding energy of 60 meV, which ensures the large exciton emission at room temperature, it is regarded as one of the most promising materials for fabricating efficient ultraviolet blue light emitting device.

氧化锌是直接带隙宽禁带半导体材料，具有较高的激子束缚能(~60meV)，可以实现室温下的紫外受激辐射，在紫外发射器件等领域具有广阔的应用前景。

The results show the dispersive curve of one-dimensional photonic crystals have the normal dispersion in the transmitted bands and abnormal dispersion in the band gaps which is similar with that of elastic electronic dipolar.

结果表明一维光子晶体的色散曲线与弹性电偶极子的经典色散曲线类似，在光子晶体的导带为正常色散，而在禁带呈现反常色散。

It also a new generation II-VI compound semiconductor with direct wide-band gap and a hexagonal wurtzite structure.

氧化锌还是新一代宽禁带、直接带隙的多功能Ⅱ-Ⅵ族六方纤锌矿结构半导体材料。

The stop band above the waveguide cut-off frequency can be controlled by tuning the varactors loaded between the arms of SRRs. Similarly, the pass band below the waveguide cut-off frequency can also be tuned by the same token.

在波导的截止频率之上，我们可以通过控制变容二极管的电容值达到控制禁带的目的，在波导的截止频率以下，我们依然可以通过改变变容二极管的电容来控制通带。

Base on the analysis, the interface between a nonlinear lefthanded material and a righthanded material can support both forward TE surface waves and backward TE surface waves under certain conditions.

针对电磁波在非线性左手系材料中的传播性质，分别研究了左、右手系材料界面以及两左手系材料界面上非线性TE表面波的传播行为讨论了导波的频率特性、色散关系以及群速度随频率的变化规律分析表明，两种界面上的非线性TE表面波均存在频率通带和禁带，且带宽是传播功率的函数揭示了在一定条件下，左、右手系材料界面上既可以支持正向传播的非线性TE表面波，也可以支持反向传播的非线性TE表面波；两左手系材料界面上表面波的传播性质因材料参量的变化差异较大，一定参量条件下，该界面上仅支持反向传播的非线性TE表面波。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。