禁带

Of these structures, the fcc structure, owing to its high symmetry, is only fit for close-packed lattice prepared by inverted-opal method.

三种结构中，fcc结构由于高对称性导致的能级简并，只适用于密堆积排列的反蛋白石结构；diamond结构非常容易产生高带隙率的完全禁带，并且可以通过调节多项参数得到所需的完全禁带；woodpile结构参数调节范围比较宽，为实验制备带来方便。

There is a less difference of ionic bond in Ti_2AlC and Ti_2AlN, the covalent bond of Ti_2AlN is larger than that of Ti_2AlC. Analysis of the total density of states, the trend forming forbidden band of Ti_2AlC was more evident than that of Ti_2AlN, which made the conductivity of Ti_2AlN than Ti_2AlC.

从总态密度可见，Ti_2AlC和Ti_2AlN都有在最低导带和最高价带之间形成较窄的禁带的趋势，即表现出形成混合型导体的趋势，而Ti_2AlC形成禁带的趋势要比Ti_2AlN更为明显，这与Ti_2AlN的电导率大于Ti_2AlC的实验结果一致。

Since the forbidden bands can appear in ranges above ultra-violet frequencies,superlattice may become a good reflectorof ultraviolet light or waves of even higher frequencies.

所得结论是：极化激元呈现为能带，在禁带内电磁波不能传播，因而将完全被材料反射，由于禁带可以出现在紫外以上的频率区间，故超晶格有可能作为紫外甚至更高频率电磁波的反射器件。

The results showed that the TiN andN films are polycrystalline phase. The properties and structure of TiN films are mainly determined by the N2 mass flow rate, and as the N2 mass flow rate increases, the structure of the TiN films transforms to f.c.c. type leading to better the properties of films. The presence of negative bias voltage can optimize the grain of TiN films, lower the defect proportion and denser the films, which improves the hardness of films. The TiN films conform to the free carrier absorption mechanism and there are many of free electrons with lower N content in TiN films. With the increase of N content, the quantity of free electrons and reflectivity of films decrease, and the plasma frequence shifts to the lower energy, which leads to the regular change of colors of films from silver, yellowy, golden to yellow-red, meanwhile the lightness of films decreases. The goldenN film consists of TiN and ZrN phase, but belongs to a sigle f.c.c. structure with (111) preferred orientation. The Zr-doping dosen't change the position of the valance band, conduction band and forbidden band ofN film, but leads to the presence of new energy levels, which is the reason thatN film remains golden. The transparent hard films with good corrosion resistance and high hardness have been prepared and the further reseachs showed that the grain size of those films is by far smaller than the wave length and the width of forbidden band of those films is very broad, is the reasons that those films are transparent.

研究表明：氮化钛和N 薄膜为多晶态，氮流量决定了氮化钛薄膜的结构和性能，增加氮流量能使氮化钛薄膜的结构向面心立方结构转变，从而得到性能良好的氮化钛薄膜；施加负偏压能优化氮化钛晶粒和减少薄膜中的缺陷，使膜层变得更致密，从而提高薄膜硬度；氮化钛主要遵循自由载流子光吸收，氮含量较少时薄膜中的自由电子数目较多，随着氮含量的增加，薄膜中的自由电子数目不断减少，反射率逐渐降低，等离子体频率向低能端移动，从而使薄膜颜色出现规律变化，由金属色银白色到淡黄、金黄再到红黄，并且薄膜亮度呈下降趋势；金黄色的N 薄膜中存在TiN 和ZrN 的分离相，但其为单一的面心立方结构并具有(111)面择优取向；相对于TiN 薄膜，Zr 掺杂后，并没有使薄膜的导带、价带和禁带发生变化，只是在TiN 禁带内增加了新能级，这也正是掺杂Zr 后，薄膜仍

The spectrum peaks nearby 530nm and 480 nm are corresponding with BTSD and BMD respectively. It is found from measurement that the luminescence peak from BMD is bluely shifted. The atoms of BTSD nearby dislocation core are affected by tensile stress along the Burger's vector direction leading to its band gap narrowed. In addition, there is the effect of part quantity of edge dislocation in BMD existed. Part of atoms in BMD are strained by compressive stress leading to its band gap narrowed, in other words, the wavelength from BMD is shorter than that from BTSD.

从测试结果中还发现BMD 的发光位较BTSD有所蓝移，分析认为BTSD位错芯附近原子沿伯格斯矢量方向只受到拉应力，致使禁带宽度变窄，BMD由于除了具有螺型位错的分量外还具有部分刃型位错的分量，而刃型位错中有部分原子受到压应力的作用，导致禁带宽度增宽，从而使得BMD的发光波长比BTSD短

The contents are: measure and tuning of accelerating cavities, coupling cavities, measure of quality, field distribution, dispersion curve . and the way of measuring and eliminating the stop band, etc. At the same time, utilizing the test data and the dispersion equation of cavity chain, we make a fit dispersion curve by way of least squares fit, and we work out the width of stop band and the intercavernous coupling coefficient.

内容包括：加速腔频率韵测量和调谐、耦合腔频率的测量和调谐、品质因素的测量、场分布的测量、色散曲线的测量、禁带的测量和消除等，同时，论文还从腔链色散方程和测得的实验数据出发，利用最小二乘法进行拟合得到拟合色散曲线，并计算出禁带的大小和腔间耦合系数。

The effect on periodic band gap of unmagnetized plasma is analyzed by its periodic structures and parameters of plasma.The electromagnetic propagation process of a Gaussian pulse through an unmagnetized plasma photonic crystal is investigated.

用时域有限差分法（Finite-Different Time-Domain，FDTD）中的电流密度卷积（Current Density Convolution，JEC）算法讨论了一维非磁化等离子体光子晶体的禁带周期特性，分析了非磁化等离子光子晶体的周期结构和等离子体参量对其禁带周期的影响。

It is an effective way to use the appropriate narrow bandgap nanosize semiconductors that is stable in chemical and biochemical conditions and not pollute the surroundings in reaction, which sensitizes nanocrysalline titanium dioxide carriers synchronously to prompt the utilization of the solar spectra and the efficiency of photocatalysis.

利用染料分子作表面敏化半导体材料和利用杂质掺杂来实现宽禁带半导体吸收光谱的扩展有一定的局限性，采用化学和生物惰性且对环境不产生二次污染的窄禁带半导体敏化同时考虑团簇颗粒粒径对载体性能的影响，是提高纳米二氧化钛光催化剂对阳光的吸收利用率和量子效率的有效方法。

Both transmission and reflection dispersion, with regard to parameters and frequency detuning, are quantitatively studied.

研究表明：光纤布拉格光栅的透射色散和反射色散在禁带边缘有很大的色散；在禁带内布拉格波长两侧，以及禁带外两侧，光纤布拉格光栅具有相反的色散特性。

By taking the effects of Ge fraction and strain on the energy band structure and effective masses into account, the analytical model of the effective densities of states of the conduction and valence bands are proposed, and the temperature and Ge fraction dependence of the effective densities of states are also studied. Following this, the temperature and Ge fraction dependence of intrinsic carrier concentration in strained SiGe layers are analytically calculated. Furthermore, carder freezeout effect and the minority carrier trapping effect of the shallow-level compensated imputities in strained SiGe layers at low temperatures are investigated.

其中，分析了应变SiGe层的临界厚度、能带结构、禁带宽度及禁带变窄模型；在考虑了Ge组份和应力对应变SiGe层能带结构的影响后，给出了较为精确的SiGe应变层的导带和价带有效状态密度的模型，并研究了有效状态密度与Ge组份及温度的变化关系；分析了应变SiGe层的本征载流子浓度及重掺杂下的禁带变窄；讨论了低温下应变SiGe层中的载流子冻析效应，并计算了SiGe应变层的电离杂质浓度与Ge组份及温度的关系；研究了应变SiGe层低温浅能级补偿杂质的陷阱效应；给出了应变SiGe层多数和少数载流子迁移率以及少数载流子寿命模型。

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。