辅助方程构造(2+1)维Hybrid-Lattice系统和离散的mKdV方程的精确解

给出双曲函数型辅助方程和函数变换相结合的一种方法，借助符号计算系统Mathematica构造了(2+1)维Hybrid-Lattice系统和离散的mKdV方程新的精确孤波解和三角函数波解. 关键词： 辅助方程 函数变换 (2+1)维Hybrid-Lattice系统 mKdV方程')" href="#">离散的mKdV方程     

MgF2单晶的THz光谱研究

利用THz时域光谱技术对MgF₂晶体(样品1)和MgF₂：Co晶体(样品2)在0.5—2.5 THz的吸收特性进行了研究.在0.5—2.5 THz波段，样品1吸收系数α(ν)随频率ν增加而增大，最大值为24 cm^-1.样品2的吸收系数比样品1大得多，Co掺杂使晶格吸收带边向低频移动，而且样品2在1.9 THz有吸收峰，吸收系数达到70 cm^-1，由此求出F^--Co²⁺离子键伸缩振动的键力常数K为3.40×10^-2　N/cm.这一结果表明，THz光谱分析有可能成为研究晶体化学键的一种重要手段.利用光学常数之间的关系计算了两个样品在0.5—2.5 THz的介电函数的实部ε₁(ν)，得到样品1的ε₁(ν)值在4.67至4.73之间，样品2的ε₁(ν)值在4.62至5.01之间. 关键词： THz辐射 光谱 2晶体')" href="#">MgF₂晶体     

Vibrational spectra of Na4P2O7·10H2O

The IR and Raman spectra are measured and analysed for sodium pyrophosphate decahydrate. The spectra are interpreted on the basis of P₂O ₇ ⁴⁻ ion and water vibrations. The observed results fit with the features predicted for the factor goup model. The appearance of two sets of frequencies in the stretching and bending regions of water suggests the existence of two kinds of water molecules in the crystal. This is confirmed by deuterium substitution.     

Effect of annealing on the opto-electronic properties of Cu0.9In1.0Se2.0 films

The influence of annealing on the structure and opto-electronic properties of Cu_0.9In_1.0Se_2.0 films prepared by solution growth technique has been studied. The films annealed at 500–520°C in air, vacuum (10^?4 torr), In-vapour and Se-vapour show polycrystalline chalcopyrite structure with orientation perpendicular to the (220) plane. Films annealed in Se-vapour at 500°C for 30 min have maximum grain size (560 Å), minimum optical energy gap, maximum absorption coefficient, lowest resistivity, maximum photosensitivity and thus are suitable for photovoltaic applications. Annealing in In-vapour or in vacuum changesp-type CuInSe₂ inton-type which possibly arises due to the increase in Se vacancies.     

三硼酸锂晶体的多光子散射

本文报道三硼酸锂(LBO)晶体的瞬态前向相干多光子散射,实验表明LBO晶体内部同时发生x~(2)和x~(3)非线性相互作用过程,而未发现光耦合效应,测量了LBO晶体的光栅寿命上限.     

AlB2和Al2B的结构与解析势能函数

运用单双取代耦合簇（CCSD）方法,选择基组6-311+g（2df）对基态B₂、Al₂分子和基组6-311g（3df）对基态AlB分子的微观结构进行优化计算,采用最小二乘法拟合得到B₂、Al₂和AlB分子的势能函数,并得到了与实验值符合很好的光谱常数.采用同种方法,选择6-31g基组,对基态AlB₂和Al₂B分子的结构进行优化计算.运用原子分子反应静力学原理得到离解极限.在此基础上,采用多体项展式法,得到AlB₂和Al₂B分子基态解析势能函数,该势能函数准确再现了AlB₂和Al₂B分子基态平衡结构特征.     

Observation of carbon‐facilitated phase transformation of titanium dioxide forming mixed‐phase titania by confocal Raman microscopy

Confocal Raman microscopy, a relatively new and advanced technique, is found to be suitable for imaging the chemical morphology below the submicrometer scale. It has been employed to probe the phase transformation of carbon‐containing titania (TiO₂) nanopowder and titania thin film subjected to laser annealing. The observation of phase transformation from the anatase phase to the rutile phase at high laser power annealing is attributed to carbon inclusion inside or on the surface of titania. Upon annealing, carbon could react with the oxygen of titania and create oxygen vacancies favoring the transformation from the anatase to the rutile phase. This study provides evidence for the carbon‐assisted phase transformation for creating carbon‐containing mixed‐phase titanium dioxide by laser annealing. We explicitly focus on the presence of carbon in the phase transformation of TiO₂ using confocal Raman microscopy. In all of the investigated samples, mixed anatase/rutile phases with carbon specifically was found at the rutile site. X‐ray diffraction (XRD), scanning electron microscopy (SEM) and energy‐dispersive spectroscopy (EDS) studies have been performed in addition to Raman mapping to verify the mixed‐phase titania formation. Copyright © 2010 John Wiley & Sons, Ltd.     

Raman spectroscopic study of the magnesium carbonate mineral hydromagnesite (Mg5[(CO3)4(OH)2]· 4H2O)

Magnesium minerals are important for understanding the concept of geosequestration. One method of studying the hydrated hydroxy magnesium carbonate minerals is through vibrational spectroscopy. A combination of Raman and infrared spectroscopy has been used to study the mineral hydromagnesite. An intense band is observed at 1121 cm⁻¹, attributed to the CO₃²⁻ν₁ symmetric stretching mode. A series of infrared bands at 1387, 1413 and 1474 cm⁻¹ are assigned to the CO₃²⁻ν₃ antisymmetric stretching modes. The CO₃²⁻ν₃ antisymmetric stretching vibrations are extremely weak in the Raman spectrum and are observed at 1404, 1451, 1490 and 1520 cm⁻¹. A series of Raman bands at 708, 716, 728 and 758 cm⁻¹ are assigned to the CO₃²⁻ν₂ in‐plane bending mode. The Raman spectrum in the OH stretching region is characterized by bands at 3416, 3516 and 3447 cm⁻¹. In the infrared spectrum, a broad band is found at 2940 cm⁻¹, which is assigned to water stretching vibrations. Infrared bands at 3430, 3446, 3511, 2648 and 3685 cm⁻¹ are attributed to MgOH stretching modes. Copyright © 2011 John Wiley & Sons, Ltd.     

二氧化钛修饰的微结构聚合物光纤预制棒制备及其在光催化中应用的探索研究

首次用二氧化钛(TiO₂)纳米材料修饰的547孔微结构聚合物光纤(MPOF)二次预制棒作为阵列化微管式光催化反应器对亚甲基兰的光催化分解进行研究.将高光催化活性的P25型二氧化钛纳米粒子均匀分散在TiO₂溶胶中,对547孔微结构聚合物光纤孔洞内壁进行铺膜,得到了负载光催化剂的阵列化微管材料.该TiO₂MPOF有序复合的阵列化微管不仅对二氧化钛纳米粒子起到负载作用,还可以作为光波导介质(rolling-up薄膜波导,聚光、导光进入二氧化钛薄膜层)、污染物反应流体通道.以有机染料亚甲基兰为模拟污染物,研究了TiO₂负载量、亚甲基兰的初始浓度及溶液pH值等因素对光降解效果的影响.该反应器547个孔道的内表面用于负载光催化剂,不仅增加了固-液接触面积,也提高了光的吸收效率,从而提高了光催化效率.迄今为止,这种兼具导光、聚光、传质、负载功能于一体的光催化反应器还未见报道.     

Mo-X(B, C, N, O, F)共掺杂TiO2体系的光催化协同效应研究

采用密度泛函理论平面波超软赝势方法, 计算并分析了Mo/X(B, C, N, O, F)共掺杂TiO₂体系的形成能、电子结构和光学性质, 研究了共掺杂协同效应对于计算体系光催化性能的影响机制. 首先计算出不同掺杂体系的态密度及能带结构, 利用能带理论分析了共掺杂效应对于禁带宽度的调控作用, 进而分析了共掺杂对TiO₂光催化能力和稳定性的协同作用. 结合电荷密度图, 分析原子间的电荷转移情况, 得到计算体系中各原子成键状态. 最后, 结合光吸收谱线分析得出Mo/C共掺杂类型在调制TiO₂体系中可见光波段的光催化性能上优势明显, 在催化作用上表现出协同效应. 本文的理论研究对共掺杂方法在TiO₂光催化领域有着一定的指导意义.