BaF2中Vk心的ESR谱分析

电子自旋共振（ＥＳＲ）实验间接表明，γ射线辐照能在室温下在ＢａＦ２微晶中产生Ｆｒｅｎｋｅｌ激子这样的元激发，此元激发受热在１５０℃以下消失。γ射线辐照使ＢａＦ２微晶中Ｆ－离子上的２Ｐ电子跃迁到外层轨道，并与２Ｐ轨道的空穴形成紧束缚的电子－空穴对——Ｆｒｅｎｋｅｌ激子。激子中的电子受热脱离Ｆ原子，这种晶格上的Ｆ０是ＥＳＲ可探测的顺磁色心点缺陷——Ｖｋ心。受γ射线辐照的ＢａＦ２微晶中含有Ｆｒｅｎｋｅｌ激子，受热时Ｆｒｅｎｋｅｌ激子湮灭。Ｖｋ心增多的现象，表现为随温度增高Ｖｋ心的ＥＳＲ信号增强的反常现象。     

两个含有平行交替链的新型二氰胺配位高聚物: {Mn(dmpz)[N(CN)2]2}2和{Cu(dmpz)[N(CN)2]2}2

Two new dicyanamide coordination polymers, {Mn(dmpz)[N(CN)2]2}2 (1) and {Cu(dmpz)[N(CN)2]2}2 (2)(dmpz=3,5-dimethylpyrazole), were synthesized and characterized by single crystal X-ray diffraction analysis and IR spectroscopy. In 1 and 2 the metal ions have two different coordination modes, where one is coordinated to four dicyanamide anions and two monodentate dmpz molecules to form a slightly distorted octahedral geometry, while the other adopts octahedral geometry, surrounded by four nitrile N atoms and two amide N atoms of the dicyanamide anions. Both complexes contain two alternating chains that are parallel to each other.     

硼离子对铕掺杂SiO2干凝胶发光性能的影响

采用溶胶-凝胶法制备了Al单掺和B，Al共掺的Eu掺杂SiO2干凝胶。利用荧光光谱、IR，XRD，DSC，TG／DTG等技术研究了硼离子、退火温度对样品发光性质的影响。经500℃以上退火处理用248nm激发的样品，产生Eu^3＋离子^5D0→^7FJ的特征发射，^5D0→^7F1的跃迁分裂为两个峰。比较615nm处的发光强度，掺硼酸样品的发光强度是不加硼酸发光强度的3．3倍。这是因为B离子的加入，在材料中形成了Si—O—B键，破坏了网络的对称性，加强了Eu^3＋的红光发射。当退火温度上升到850℃用350nm激发时，样品有很强的Eu^2＋蓝光发射。Al单掺的发射中心在437nm处，发射半峰宽约为70nm，而B，Al共掺样品的发光中心蓝移到425nm处，单掺样品的蓝光强度几乎是共掺样品强度的2倍。这是由于硼酸的加入改变了基质的网络结构，从而导致单掺和共掺样品发射峰位和强度的改变。     

Three-component one-pot total syntheses of glyantrypine, fumiquinazoline F, and fiscalin B promoted by microwave irradiation

A microwave-promoted three-component one-pot reaction has been developed to provide access to the core pyrazino[2,1-b]quinazoline-3,6-dione (1) scaffold, which is common to several families of alkaloids with significant biological activities. By adapting this synthetic strategy through the use of selected Boc-amino acids and amino acid esters, we have accomplished highly efficient and concise total syntheses of glyantrypine (2), fumiquinazoline F (3), and fiscalin B (5), achieving overall yields of 55, 39, and 20%, respectively.     

Unprecedented isospecific 3,4-polymerization of isoprene by cationic rare earth metal alkyl species resulting from a binuclear precursor

The isospecific 3,4-polymerization of isoprene has been achieved for the first time by use of a combination of a binuclear rare earth metal dialkyl complex, such as [Me2Si(C5Me4)(mu-PCy)YCH2SiMe3]2 (Cy = cyclohexyl), and an equimolar amount of [Ph3C][B(C6F5)4] as a catalyst system. A DFT calculation suggested that a binuclear monocationic monoalkyl species, such as [Me2Si(C5Me4)(mu-PCy)Y(mu-CH2SiMe3)Y(mu-PCy)(C5Me4)SiMe2]+, in which the alkyl group bridges the two metal centers, could be the true catalyst species.     

A simple method for large-scale preparation of ZnS nanoribbon film and its photocatalytic activity for dye degradation

ZnS nanoribbon film has been successfully prepared by solvothermal treating of Zn foil and S powder in hydrazine hydrate without any surfactant and post-high temperature treatment. The prepared samples were characterized by XRD, SEM and PL. Results show that the obtained films were with high crystallinity and uniformity. The obtained samples were used as a photocatalyst for degradation of dye X-3B, and results show that the dye can be photocatalytically degraded with high rate by as-prepared ZnS nanoribbon film under UV light irradiation.     

Self-focusing in two-color collinear optical Kerr measurements

We performed the femtosecond two-color collinear optical Kerr shutter (OKS) measurements in a thick Kerr medium. The time-resolved OKS signals showed a multi-peak structure and a large broadening with respect to that for non-collinear. By measuring the time-resolved OKS signals in the sample at different powers, we demonstrated that the abnormal profile of the OKS signals was mainly attributed to self-focusing and re-focusing of the pump beam in the Kerr medium and the group velocity difference between the pump and the probe beams.     

共沉淀法制备Zn-La-Al型混合金属氢氧化物纳米材料及其性能研究

采用非稳态共沉淀法制备了 Ｚｎ Ｌａ Ａｌ 型混合金属氢氧化物纳米颗粒材料，研究了沉淀过程的机理、产品的化学组成、粒度、晶态、等电点和红外光谱等，考察了沉淀剂（ Ｎ Ｈ４ Ｏ Ｈ、 Ｎａ Ｏ Ｈ 和 Ｋ Ｏ Ｈ） 对产品性能的影响