晶体

According to the boundary relations of the electromagnetic field, and based on the phenomena of double refraction and double reflection in crystals, the reflectivity and transmissivity are deduced at boundary when an extraordinary beam is incident from an isotropic medium upon a crystal or from a crystal to an isotropic medium with optical ax.

为分析非常偏振光在晶体表面的能量损耗，给出一种求解反射率和透射率的方法，即根据电磁场的边值关系以及晶体的双折射和双反射现象，求解晶体光轴在入射面内时，非常偏振光从各向同性介质入射到晶体和从晶体出射到各向同性介质两种情况的反射率和透射率的方法，并给出反射率和透射率的解析解，同时得到对于晶体光轴在入射面内的情况，光轴的取向对非常偏振光反射率的大小几乎没有影响，但对产生全反射的临界角θc影响较大的结论。

The relationship between the orientation of tetrahedral [SO4]2- in sulfate crystals such as barite,anhydrite, epsomite and jarosite and their morphology was studied from the standpoint of crystal chemistry,and the formation inechanisin of their morphology was analysed according to the structural orientation of tetrahedral [SO4]2- and the bonding energy between [SO4]2- and metal ions [M2+] during growth.

本文从硫酸盐类晶体中负离子配位多面体的结晶方位和相互联结的稳定性出发，探讨了硫酸盐类晶体中[SO4]2-结晶方位与晶体结晶形貌之间的关系；认为[SO4]2-四面体与金属阳离子（Ba2+、Ca2+、Mg2+…）结合时，由于晶体结构和生长条件的不同，在晶体各族晶面上的叠合速率和取向不同；晶体的结晶形貌迥然有别。

The completely diagonalized Hamiltonian matrices of 3d2/3d8 ion configuration in the trigonal symmetry have been established by irreducible representation method. Taken into account the influence of the spin-spin coupling interactions omitted in previous publications, the spectra and the constants of crystal structure and zero-field splitting parameters of CsNiCl3 crystal and CsNiCl3: Mg2+ crystal are calculated and the influence of the doping to the spectra, the constants of crystal structure, zero-field splitting parameters and Jahn-Teller effect are studied. The results show that doping can change the structure of crystal which brings about the changes in the spectra and zero-field splitting parameters as well as Jahn-Teller effect.

应用不可约张量理论构造了三角对称晶场中3d2/3d8态离子的45阶可完全对角化的微扰哈密顿矩阵，在考虑了以前工作中被忽略的自旋-自旋耦合作用的基础上计算了CsNiCl3晶体和CsNiCl3：Mg2+晶体的基态能级、晶体结构、零场分裂参量和Jahn-Teller效应，研究了掺入Mg2+对CsNiCl3晶体的光谱、零场分裂参量及Jahn-Teller效应的影响和自旋单重态对基态能级的贡献，发现掺杂使得晶体结构产生畸变，从而改变晶体光谱的精细结构和零场分裂参量，不改变Jahn-Teller效应的分裂规律但改变分裂的大小。

We studied the structural characteristic of AR2O4 crystals within calcium ferrite type, ABO4 crystals in zircon, monazite, and scheelite type, R2M2O7 crystals in pyrochlore type and - and -type R2MoO6 crystals, and performed systematical calculations on the chemical bond parameters, thermal expansion coefficients and bulk moduli of these crystals.

对铁酸钙型AR2O4晶体、锆石、独居石和白钨矿型ABO4晶体、烧绿石型R2M2O7晶体和-和-R2MoO6晶体等复杂体系的结构进行研究，并系统的计算了各晶体组成化学键的属性以及表征晶体膨胀和压缩行为的膨胀系数和体模量等参数。

Since polar organic crystals have noncentric structures, the existence of polar axis in the crystals has a significant effect on the molecular arrangement and on the crystal growth.

极性有机晶体在不同的溶剂中具有明显不同的生长习性，主要有两个方面的原因：一是极性有机晶体属非中心对称性晶类，晶体具有极轴，极轴的存在对分子堆积和晶体生长具有重要影响；另一是极性有机晶体的界面结构不同，溶剂与晶体界面的相互作用不同，使得晶体同一面族的生长速率不同，从而导致了晶体习性的改变。

The inperfect crystal structure and its analysis for materials, is an elective course for the master graduate student, which include the crystallology principle, development of crystal diffraction, crystal determination and computer simulation of new phase, analysis of solid solution and superstructure, correction of crystal structure and bondvalent theory, analysis of inperfect crystal structure, analysis of amorphous structure and so on.

材料不完整晶体结构及其分析方法，为材料科学及工程等专业硕士研究生的选修课，内容包括晶体学基础、晶体衍射技术最新进展、新相晶体结构测定与数值模拟、固溶体与超结构分析、晶体结构修正与价键理论、不完整晶体结构分析、非晶结构分析等。

Photonic quantum-well structures can be constructed by stacking 3 photonic crystals with the same photonic band gap and different defect modes. On condition that the defect mode of the PC in the well region is located into nontransmission frequency ranges of the PCs in the barrier regions, the confined photonic state appears and can completely transmit through the structure by tunneling. However, its transmission will be strongly prohibited due to vanishing of the photonic QW induced by shifting the defect mode frequency of either of the PCs in the surrounded regions to that of the middle PC.

把三块各带有一个缺陷的光子晶体结合起来，如果中央晶体的缺陷模处在两侧晶体的禁带中，缺陷模内的光波会受到两侧晶体的阻碍并被局域在中央晶体内，形成量子阱结构；若一侧晶体的缺陷模被移动到中央晶体缺陷模处，则只有一侧晶体阻碍在中央晶体缺陷模内传播的光波，量子阱效应完全消失，光的传输受到最大程度的阻碍。

The possible reason is that doped Zr〓 ion enters the interstitial sites for its small ionic radius and no dipole complexes were formed. Monovalent ion F〓 has been reported to improve the scintillating performance greatly. Our results show that Agrand diagrams of F〓: PWO crystals obey an modified Cole-Cole equation. The crystals present similar dielectric relaxation phenomena to but have much higher activation energy than that of RE〓: PWO crystals, which originate from the 〓 dipole complexes. The co-doping of trivalent Y〓 and pentavalent ion Nb〓 does not always show a better scintillation performance than that of solely doped samples, which could be attributed to the existence of the 〓 dipole complexes, which counteract the solely doping effect.

而Zr〓由于离子半径太小，可能进入间隙位置，不形成类似的偶极缺陷；一价负离子F〓的掺入提高了晶体闪烁性能，阻抗谱测试结果表明F〓：PWO晶体Argand图符合修正的Cole—Cole方程，晶体同样表现出介电弛豫现象，并具有比RE〓：PWO晶体中高得多的弛豫激活能，可能起源于形成的〓偶极缺陷；Y〓和Nb〓双掺的PWO晶体并没有显示出两种离子单掺优点的叠加，阻抗谱测量结果表明，在双掺晶体中可能形成〓偶极缺陷，使两者掺杂作用相互抵消。

The optical characterization methods were used in the study of the defects of transparent crystal in visible light and the near UV absorption topography method is used in the study of the defects and relationship between defect and growth facets because scintillant BGO crystals, when suffered radiation damage,have a high absorption coefficient for light of short wavelength.

除使用通常研究透明晶体的光学方法外，由于BGO晶体在受到光辐照损伤时时短波长光具有高的吸收系数，因此还采用近紫外光吸收形貌法研究晶体缺陷，以及缺陷与晶体小面之间的关系，并根据BGO晶体的结晶习性和小面形成机理提出了减少和消除晶体小面生长及缺陷的方法。

The α-BaB〓O〓 crystal is colorless, transparent and without cracking. The cracking problem has been overcome by a special growth procedure. The dislocation density, crystallization morphology and growth habit of α-BaB〓O〓 crystal have been systematically studied by chemical etching method, X-ray laue orientation of synchrotron radiation, double-crystal diffraction topography. The growth striation and irregular dislocation consist of the primary defect in α-BaB〓O〓 crystal. The convex solid-liquid interface is stable during the whole growth process.

在国际上首次采用提拉法生长出φ50×40mm〓的α-BaB〓O〓晶体，生长方向为[0001]，晶体完整、无色透明；提出了三种固相反应的原料制备方法，并保证B〓O〓过量1mol%；采用独特的生长装置和程序有效地解决了α-BaB〓O〓晶体易开裂的问题；首先采用化学腐蚀法、白光X射线衍射术、X射线双晶衍射形貌术等研究了α-BaB〓O〓晶体的位错密度；首次采用同步辐射X射线劳埃定向术研究了α-BaB〓O〓晶体的结晶形态及生长习性；结果发现α-BaB〓O〓晶体的缺陷以位错为主，部分α-BaB〓O〓晶体中存在生长条纹。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。