晶体

Based on the result of normalized frequency with effective refraction index -1 versus inner radius of ring-shaped holes we theoretically analysis the effects of structure parameters to equifrequency contours of respective normalized frequency and imaging properties.

通过光子晶体有效折射率的计算，得到了有效折射率为-1 的电磁波频率随空气环内径由0～0.2a 变化的规律，并由对应等频曲线的变化解释了结构参数对光子晶体平板成像的影响。

Key words: sodium yttrium tungstate crystal doped with neodymium; Raman spectra; absorption spectrum; Czochralski method

为此，采用提拉法生长了 Nd ， NYW 晶体，分析了晶体的红外光谱、 Raman 光谱和吸收光谱。

One of these patients received Arcysof Natural IOL in the left eye and Arcysof single-piece IOL in the right eye.

其中1例左眼为Acrysof Natural人工晶体，右眼为一片式Acrysof人工晶体。

Based on the analysis and investigation of different testing methods for determining the morphology, the crystallographic structure and orientation of graphite in cast iron, a set of more comprehensive and accurate analytical methods was advanced in this paper.

在分析考察以前各种对铸铁石墨结构及晶体位向的测试方法基础上，本文提出了一套研究石墨形貌、晶体结构和位向的更为综合和准确的检测方法。

This thesis proposed the design and implementation of an ASIC for the motor control with DTC technology. Note that this ASIC is implemented by cell-based Design style with Verilog language.The basic principle of the Direct Torque Control is to select the switch sequence of the inverter. Those switches will control the magnetism and torque of the stator, to induce a fast response of the induction motor. Furthermore, the d-q axle's static coordinate, which is transferred from both the three-phase current and voltage, is used to compute the stator's magnetism and torque. By comparing with original values, those magnetism and torque will be calculated and set to new data. Then the switching table and the hysteresis controller are decided with the new data to generate a voltage vector and to control the stator magnetism and torque.

直接转矩控制的基本原理为经由侦测马达定子磁通与转子转速，来适当的选择变频器功率电晶体的切换状态，以获得快速且不易受外在环境影响的马达控制响应；首先，根据量测三相电流与利用变频器的切换状态取得马达的三相电压，将其转换至d-q轴静止座标，然后藉此估测马达的磁通量与转矩量，再分别与侦测的定子磁通量和转矩量比较后，得到定子磁通量与转矩量比较的结果，再利用DTC电压向量切换表(DTC Voltage Vector Switching table)，依定子磁通与转矩的比较值及马达所在的角度位置，来选择一个适当的电压向量，进而依切换顺序来激发功率电晶体，达到控制感应马达的目的。

In summary, various key experimental conditions in electron acoustic imaging of ferroelectric domains were systematically studied. The optimum experimental conditions to obtain EAI of domains with good quality and the factors important to image analysis have been presented. The piezoelectric vibrator model and calculation of motion equation are helpful for explaining the imaging mechanism and related experimental phenomena. The sample holder with variable electric field was designed. The domain movement of BaTiO〓 ceramics and crystal under lateral and longitudinal applied electric field and domain movement of PMN-PT crystal under longitudinal poling electric field were observed. The application of SEAM on revealing of ferroelastic domains, imaging of residual stress distribution in ceramics coatings and around the pores on the surface of ferroelectric ceramic composite have been reported respectively. All these works enriched the study of electron acoustic imaging and extended the application of SEAM in the characterization of materials.

综上所述，本文系统地研究了各项关键实验条件对电畴电声成像的影响，指出了获得最佳畴结构电声像的条件和成像分析中应当考虑的各种影响因素；提出了解释电畴电声成像的压电振子模型，在此基础上推导并求解了压电振子运动方程，并对一些实验现象作出了解释；成功地设计了可变电场的样品台，观察了BaTiO〓陶瓷和晶体在横向电场作用下的畴运动，PMN-PT晶体在纵向极化电场作用下的畴运动；探索了电声显微镜在铁弹畴成像，陶瓷涂层应力观察，陶瓷自然表面气孔周围应力成像的应用，这些研究，丰富了电声成像的学术内涵，拓展了电声显微镜的应用领域。

Salt happens to be a crystal in which, except for defects in the structure of the crystal lattice , the position of every sodium and chlorine atom is predetermined .

盐正好是晶体，在晶体中，除非晶格结构有缺陷，每个氯原子和钾原子的位置是固定的。

So the treatment of cataract rest with the early diagnosis and prevention.

因此，通过对晶体图像分析系统的诊断指标与相应状态下的晶体形态学、生化改变等进行对比研究，制定白内障的诊断标准和定量的分期分级标准，这样就有一可参照的标准，不但可以对白内障作出早期的判断，对抗白内障药物疗效也会作出正确的评价。

Furthermore, combined with the structure of LBO crystal, the formation mechanism of dislocation is proposed.

总结了LBO晶体中位错的形成规律，联系LBO的晶体结构，探讨了位错的形成机制。

The results show that the average crystal size of terephthalic acid increases obviously during the aging process,but the changing of water content has not obvious influence on the aging process.

研究了高温下含水量对粗对苯二甲酸晶体粒度和固液两相中杂质浓度的影响，结果表明：熟化能增加对苯二甲酸晶体的平均粒径，但含水量变化对熟化过程影响不明显。

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。