C6H2(NO2)3ONH4的单晶制备和晶体结构

This paper introduces the preparation method of single crystal and the molecular structure of ammonium picrate.The obtained results show that the crystal of ammonium picrate belongs to orthorhombic, Ibca space group.The crystal parameters of the ammonium picrate was given in the paper .a=7.131(1),b=13.487(1),c=19.810(2),V=1905.2(4)³,Z=8,D_c=1.716mg/cm³,μ=0.159mm^-1,F(000)=1008。     

热色液晶红外传感器和摄像仪

红外摄像系统包括热色液晶红外传感器、斩波器、控制器、光源、透镜、液晶相位推移器、微处理器、光学系统、ＣＣＤ阵列等,描述了热色液晶红外摄像系统的工作原理和特性。     

3,6-二（3 ′-氨基呋咱-4-基）-1,4-二氧杂-2,5-二氮杂环己-2,5-二烯的晶体结构（英）

制备并表征了化合物3,6-二(3'-氨基呋咱-4-基)-1,4-二氧杂-2,5-二氮杂环己-2,5-二烯(BADDD) .其晶体结构参数为:Mr=252.17,三斜晶系,P-1空间群,a=0.48616 (10) nm,b=0.5237 (2) nm,c=0.97076 (19) nm,α=102.25(3)°,β=93.631(17)°,γ=101.88 (2)°,V=0.23489 (12) nm3,Z=1,Dc=1.783g·cm-3,λ (MoKα)=0.071073 nm,μ(MoKα)=0.153 mm-1,F(000)=128,T=294 (2) k,R1=0.0351 and wR2=0.0875.BADDD分子由两个氨基呋咱环和一个由两个O原子,两个N原子和两个C原子组成的六元杂环构成.分子具有中心对称性.     

光子晶体光学频率变换技术

文章首先介绍了光子晶体光学频率变换技术的基本原理和技术特点;然后简述光子晶 体光学频率变换技术研究进展情况;最后指出了光子晶体变频技术在可调谐激光器和其它领域中的应用前景。     

氨法铁红晶种转化机理探讨

论述了氨法氧化铁红合成中真实晶核(二次晶种)在氧化合成(二步氧化)初期的形成过程,并强调了控制二次晶种的形成对产品质量和产量的重要作用。在湿法合成工艺中,氧化合成初期的条件有利于转化为α-Fe2O3晶核。     

Photoluminescence characterization of AlGaN-GaN pseudomorphic quantum wells and calculation of strain induced bandgap shifts

The low temperature (77 K) photoluminescence characteristics of Al _x Ga_1-x N-GaN strained layer quantum wells with differentx values grown by metalorganic chemical vapor deposition (MOCVD) were investigated. The photoluminescence spectra were useful in analyzing both quantum confinement effects and strain induced energy shifts. The strain induced shifts were found to be a strong function of aluminum compositionx. A model was developed to calculate the strain induced bandgap shifts atk = 0. The values predicted by this model which took into account the wurtzite crystal structure of the material system, were in good agreement with (i.e. within 2 meV of) the experimentally measured shifts.     

Determination of the direction of the crystal optical axis of ground uniaxial precious stones by means of polarized-light microscope photometry

The direction of the crystal optical axis of a uniaxial microscopic object is determined on the basis of the known correlation between this direction, the displacement of isogyres of the conoscopic figure, and the rotation of the microscope stage. It is shown that the use of photoelectric equipment for indicating the displacement, a stepping motor controlled by a microprocessor for rotating the stage, and a desk calculator for processing the photometric data provides a more convenient and accurate determination than classicial procedures, involving visual inspection and manual operation. The method is particularly suitable for uniaxial crystals of the size and shape of precious stones.     

Bridgman法生长的PWO晶体的发光特性和透光特性

本文采用改进的Bridgman法，以纯度不低于99．99％的PbO和WO3为原料，生长出无色透明的、大尺寸的PbWO4（PWO）晶体，研究了晶体沿生长方向不同部位的透射光谱及X射线激发的发射光谱特性．发现改进的Bridgman法生长的PWO晶体具有较好的发光均匀性和透光均匀性，其原因主要是改进的Bridgman法采用密封的坩埚，有效地抑制了组份（PbO和WO3）的挥发.     

全芳族液晶共聚酯的合成与表征

以对乙酰氧基苯甲酸，对苯二酚二乙酯和间苯二甲酸合成了一系列全芳香族热致性液晶共聚酯，并用ＩＲ，ＤＳＣ和热台偏光显微镜等方法对共聚酯进行了分子结构和液晶相行为的表征。     

涡轮叶片材料及制造工艺的研究进展

针对航空发动机涡轮叶片的工作环境和使用要求,介绍了提高涡轮叶片耐温能力的两种途径,即加强叶片冷却和提高叶片材质自身的耐温性能。文中着重评述了用作叶片材料的合金及其制造工艺的研究进展与发展趋势。