“四模块”嵌入下的混合式教学设计与实践*——以功能材料专业物理化学基础课程为例

为建设适应新时代要求,突出高阶性、创新性、挑战度的一流本科课程,实现价值引领、能力培养和知识传授的教育教学目标,结合功能材料专业的特点和民族高等院校学生的学情,构建了物理化学基础课程的“四模块、三阶段、两时空、双平台”的混合式教学新模式,重塑了“价值引领模块、基础理论模块、多学科融合模块和虚拟仿真实验模块”的“四模块”内容体系。通过“四模块”嵌入下的混合式教学实践研究,结合学生的课前、课中、课后等学习成绩,多维度评价学习效果,并藉由调查问卷来分析学生对混合式教学的评价,最终研究结果表明学生的个性化自主学习能力有了显著提高、学生运用物理化学理论解决复杂问题的综合能力得到了提升,学生经过刻苦学习获得了素质提高的成就感。     

微量钛掺杂的纳米二氧化锆相变过程中的光学性质

微量钛掺杂的纳米氧化锆由于纳米“小尺寸效应”的影响,在材料中产生了过量的氧空位缺陷,这些氧空位缺陷使得氧化锆在室温下呈现出高温的四方相。这种晶相的变化对氧化锆的光学性质产生了很大的影响。在氧化锆从四方相向单斜相的转变过程中,位于470 nm位置的Ti发光中心的宽带发光以及相同位置的余辉发光得到了增强。     

合成GaP纳米晶过程的关键影响因素

本文系统研究了在有机溶剂中常压合成GaP纳米晶过程中反应温度、反应时间、反应体系的均匀性和原料的比例等关键影响因素.GaP纳米晶的产率、形貌以及平均粒度随着这些关键因素的改变有很大的不同.制备的GaP纳米晶用X射线衍射仪和透射电镜进行了表征.发现了最优化的合成工艺条件,实现了GaP纳米晶的高产率(达85;)制备,而且形貌和粒度可以根据需要进行调控.     

Characteristics of High In-Content InGaN Alloys Grown by MOCVD

InN and In0.46 Ca0.54N films are grown on sapphire with a CaN buffer by metalorganic chemical vapour deposition （MOCVD）. Both high resolution x-ray diffraction and high resolution transmission electron microscopy results reveal that these films have a hexagonal structure of single crystal. The thin InN film has a high mobility of 4 75 cm^2V^-1s^-1 and that oflno.46 Gao.54N is 163 cm^2 V^-1s^-1. Room-temperat ure photoluminescence measurement of the InN film shows a peak at 0.72eV, confirming that a high quality InN film is fabricated for applications to full spectrum solar cells.     

使用SiNx原位淀积方法生长的GaN外延膜中的应力研究

采用低压MOCVD系统,在生长过程中使用SiNx原位淀积的方法产生纳米掩模,并在纳米掩模上进行选区生长和侧向外延制备了GaN外延薄膜.使用拉曼光谱和光荧光的手段对GaN外延膜中的残余应力进行了研究.研究发现,用SiNx原位淀积出纳米掩模后,GaN生长将由二维向三维转变,直到完全合并为止.利用拉曼光谱和光荧光谱分别研究了薄膜中的残余应力,两者符合得很好;这种方法生长出的GaN薄膜的应力分布较传统的侧向外延更加均匀;并且从中发现随着生长过程中SiNx原位淀积时间的增加,生长在其上的GaN外延膜中的残余应力减小.这是因为,随着SiNx原位淀积时间的增加,SiNx纳米掩模的覆盖度也增大.因此侧向外延区的比例增大,残余应力随之减小.     

Interplay between spin frustration and magnetism in the exactly solved two-leg mixed spin ladder

We study a mixed spin-(3/2,1) ladder system with antiferromagnetic rung coupling and next-nearest-neighbor interaction.The exactly solved Ising-chain model is employed to investigate the ground-state properties and thermodynamics of the low-dimensional ladder system.Our results show that the competition between different exchange couplings brings in a large variety of ground states characterized by various values of normalized magnetization equal to 0,1/5,2/5,3/5,1.Moreover,an interesting double-peak structure is also detected in the thermal dependence of magnetic susceptibility and specific heat when the frustration comes into play.It is shown that the double-peak phenomenon at zero-field for the case of AF_2 ground-state arises from the very strong antiferromagnetic rung coupling,while other cases are attributed to the excitations induced by temperature and external field around the phase boundary.     

两个基于三氰构筑单元三核氰基簇合物的合成、结构与磁性研究

在咪唑(im)或者三乙烯四胺(tetraen)存在的条件下,反应Bu4N[Fe(Tp)(CN)3]和(Bu4N)[(Tp*)Fe(CN)3](Tp=Tris(pyrazolyl)hydroborate,Tp*=hydridotris(3,5-dimethylpyrazol-1yl)borate)三氰基前驱物与Ni(ClO4)2·6H2O得到两个新型的氰基桥联{Fe2Ni}异金属三核簇合物{[Fe(Tp)(CN)3]2[Ni(im)4]}(1)和{[Fe(Tp*)(CN)3]2[Ni(tetraen)]}·12H2O(2).采用X射线单晶衍射法确定分子结构.在这两个晶体中,每个FeI I离子与三个氰基碳原子以及Tp(或者Tp*)阴离子中的三个氮原子配位.而每个Ni I离子与两个氰基氮原子以及来自四分子咪唑或者一分子三乙烯四胺分子中的四个氮原子配位,这些Ni I离子通过三氰基构筑单元相连接形成两个{Fe2Ni}三核簇合物.磁性测试表明,在晶体1和2中的低自旋FeI I(S=1/2)离子和高自旋NiI(S=1)离子间存在强烈的链内铁磁性相互作用.     

Yb3+掺杂对Er3+:NaYF4上转换发光的调制作用

采用溶胶-凝胶(Sol-gel)法制备了2 mol％ Er3+、0,20和80 mol％ Yb3+共掺杂NaYF4上转换发光粉末.Er3+:NaYF4为α-NaYF4相和β-NaYF4相的混合结构,Yb3+共掺杂促进了β相到a相的转变.在976 nm半导体激光器(LD)激发下获得了对应于Er3+的2 H11/2/4 S...     

有机芳香烃掺杂控制C_(60)微/纳米晶形貌和发光

C60高度的分子对称性使其能带间的电子跃迁被禁止,导致其发光很弱。为了提高C60纳米晶的发光强度,采用挥发C60的芳香烃饱和溶液的方法,一步合成了芳香烃溶剂化的C60纳米晶。实验结果表明,有机溶剂的掺杂在不同程度上增强了C60纳米晶的发光,其原因可能是溶剂的掺杂破坏了C60的高度的分子对称性。     

Syntheses,Structures, Electrochemistry and Magnetic Properties of Two Trinuclear Cyanide-bridged Clusters Based on Tricyanometalate Building Block

The reaction of tricyanometallate precursor, Bu_4N[Fe(Tp)(CN)_3] and(Bu_4N)[(pzTp)Fe(CN)_3](Tp = tris(pyrazolyl)hydroborate, pzTp = tetrakis(pyrazolyl)borate) with Ni(ClO_4).26 H_2O in the presence of the monodentate N-methylimidazole ligand afforded two new cyano-bridged heterobimetallic {Fe2 Ni} trinuclear clusters, {[Fe(Tp)(CN)_3]_2[Ni(Mim)_4]}·8 H_2O(1) and {[Fe(pzTp)(CN)_3]_2[Ni(Mim)_4]}·2 CH_3OH·2H_2O(2). The molecular structure was determined by single-crystal X-ray diffraction. In the two compounds, the FeIII ions were coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp(or pzTp) anions, whereas, the NiII ions were surrounded by two cyanide nitrogen atoms and four nitrogen atoms from four monodentate N-methylimidazole ligands, and they were bridged by tricyanometalate building block to form similar {Fe2Ni} trinuclear clusters. Cyclic voltammetry(CV) measurements indicated that compound 1 exhibited two quasireversible iron-centered reduction processes at –0.71 and –0.17 V and one quasireversible nickel-centered oxidation process at 0.92 V, while compound 2 showed two quasireversible iron-centered reduction processes at –0.66 and –0.09 V and one quasireversible nickel-centered oxidation process at 0.88 V. Magnetic measurements showed that compounds 1 and 2 exhibited strong intrachain ferromagnetic interaction between the low-spin Fe~Ⅲ(S = 1/2) and high-spin Ni~Ⅱ(S = 1) ions.