MMgF4(M=Ca,Sr, Ba)体系中Eu和Tb的电荷迁移

于不同气流中, 合成了MMgF4:xEu,yTb复合氟化物磷光体。该体系中Eu^3^+和Eu^2^+共存。Tb的存在影响Eu的价态存在形式。ESR测试表明, 随Tb的掺入浓度增加, Eu^2^+的浓度呈规律性变化。随Eu的掺入, 样品的XPS谱中出现了四价铽的Tb3d5/2特征伴峰。认为Eu^3^+和Tb^3^+之间存在电荷迁移平衡。即Eu^3^++Tb^3^+=Eu^2^++Tb^4^+。通过半定量手段研究了SrMgF4中这一衡的平衡常数。     

BaLaB_9O_(16)∶Eu,Tb的真空紫外光谱特性

采用高温固相反应法合成了BaLaB9O1 6 ∶RE (RE =Eu ,Tb)等离子荧光体 ,测量了它们的真空紫外激发光谱和 14 7nm激发下的发射光谱。结果表明 ,硼氧阴离子基团基质吸收带位于 15 0nm附近 ,Eu3 电荷迁移带位移 2 5 0nm附近 ,Tb3 的 4f 5d吸收位于 15 0～ 2 60nm的区域内 ,相关数据表明 ,基质与稀土离子之间存在能量传递。     

Eu~(3 )在CaYBO_4中的取代和发光

用固相法制备化合物CaY1 -xBO4∶xEu ,研究Eu3 在CaYBO4中的取代格位和发光特性。当Eu3 掺杂浓度不大时 ,存在两个发光中心 ,认为是取代基质中有两个Y格位的结果 ;通过对Eu O的电荷迁移激发带位置的分析 ,表明Eu3 所处八面体中心格位的对称性越低 ,Eu O的电荷迁移带越偏向于短波 ;当Eu3 的掺杂浓度较大 (x >0 1 0 )时 ,Eu3 离子也可占据Ca2 格位 ,同时Eu3 还原成Eu2 。     

Ce4+和Eu3+共掺杂的Ca2SnO4发光材料的合成与光谱特性

利用高温固相反应法合成了Ce4 和Eu3 共掺杂的Ca2-xEuxSn1-yCeyO4样品,并对其结构和发光特性进行了研究。X射线衍射结果显示,在Ca2SnO4中同时掺入Ce4 和Eu3 离子没有改变其晶体结构。Ca2-xEuxSn1-yCeyO4样品的发射光谱随Eu3 掺杂浓度产生很大变化,当Eu3 掺杂浓度低时,样品中同时存在着Ce4 -O2-的蓝光发射和Eu3 的红光发射;当Eu3 掺杂浓度较高时,样品呈现出Eu3 离子的红光发射。Ce4 -O2-蓝色发光的寿命约为81μs,其能量来源于O2-和Ce4 离子间的电荷迁移吸收;而Eu3 红色发光的寿命约为830μs,其能量来源于O2-和Eu3 离子间的电荷迁移吸收。Eu3 -O2-键比Ce4 -O2-键更容易吸收紫外光,两者之间没有能量传递现象。     

Eu:GGG纳米荧光粉体制备及其光学特性

采用液相共沉淀方法并在不同烧结温度下制得了Eu：GGG荧光粉体。用X射线衍射分析了样品的结构，计算了其晶格常数，为1．2371nm。室温下，测量了Eu：GGG的光致发射光谱、激发光谱和荧光衰减曲线。激发光谱在波长240～287nm的谱带内和393。。处有强的激发，分别来自于Eu^3＋O2^-间的电荷迁移态吸收和Eu“的^7F0→^5L6的跃迁吸收，同时在274nm处也出现了Gd^3＋的^8S7/2→^6I1的特征吸收。393nm激发下，591nm处的发射峰最强，对应Eu^3＋的^5D0→^7F1的磁偶极跃迁，可能由于部分Eu^3＋处于反演中心对称格位所致。随着烧结温度升高，Eu：GGG的发光强度增强，这可能由于随着烧结温度升高，样品晶粒尺寸变大，单位体积内被激发的Eu^3＋离子数增加引起，而591nm发光的荧光寿命变短，可能是由Eu^3＋离子的能量共振传递过程中发光被陷阱捕获所致。     

CaBPO5∶RE(RE=Eu,Tb)的水热合成及其发光特性

利用水热法合成了CaBPO5∶RE(RE=Eu,Tb)荧光体并测试了其结构和光谱, 讨论了其发光性质, 并与高温固相法合成的产物作了对比. 结果表明, 由于电子转移, Eu3+, Tb3+和Eu2+共存于同一体系中, 而且Eu2+的发射位置从402 nm移至428 nm. 在双掺杂体系中引入Ce3+, Eu3+, Tb3+和Eu2+的发光强度均有所增强, 这可能是Ce3+与Eu3+之间的电子转移及各种稀土离子之间能量传递相互竞争的结果.     

BaLaB9O16：Eu,Tb的真空紫外光谱特性

采用高温固相反应法合成了BaLaB9O16:RE(RE=Eu,Tb)等离子荧光体，测量了它们的真空紫外激发光谱和147nm激发下的发射光谱。结果表明，硼氧阴离子基团基质吸收带位于150nm附近，Eu^3 电荷迁移带位移250nm附近，Tb^3 的4f-5d吸收位于150－260nm的区域内，相关数据表明，基质与稀土离子之间存在能量传递。     

GdPO_4∶Eu~(3 )和GdBO_3∶Eu~(3 )中“Gd-Eu”间的能量传递

利用同步辐射光源(德国HASYLAB实验室的SUPERLUMI实验站)对高温固相法制备的GdPO4∶Eu3 和GdBO3∶Eu3 的发射谱与激发谱进行了研究,并从量子剪裁的角度对“Gd3 -Eu3 ”之间的能量传递作了讨论。在两种样品监测Eu3 红光发射的激发谱上,都显著观察到了对应Gd3 离子4f-4f跃迁的谱线,说明从基质中Gd3 离子向掺杂的Eu3 离子之间存在非常有效的能量传递,这有利于量子剪裁的发生。在激发谱上还观察到了对应Eu3 -O2-电荷迁移态的宽激发带(180~270nm),而对应Gd3 离子8S7/2→6GJ跃迁的谱线(196nm,203nm)叠加在这个宽带之上,微弱可辨,这不利于Gd3 -Eu3 间交叉弛豫的能量传递过程,从而不利于量子剪裁的发生。结合Eu3 -O2-电荷迁移态位置变化的规律,提出了如何避开其干扰以增强量子剪裁效应的材料设计方案。     

M2B5O9X∶Eu,Tb(M=Ca,Sr;X=Cl,Br)荧光体的光谱特征

利用Eu3+和Tb3+稀土离子之间存在电子组态共轭性的特征,将其双掺于同一基质中,由于电子转移而产生Eu2+,使Eu3+,Tb3+和Eu2+共存于同一体系中.在空气中合成了M2B5O9X∶Eu,Tb荧光粉,研究了其发光特征及影响作用.结果表明,Eu3+,Tb3+和Eu2+共存于同一基质中,且稀土离子的掺杂量对其光谱产生影响.     

Ca2Y7.9（SiO4）6O2-0.5xFx:Eu0.1（3+,2+）荧光粉的合成和发光特性

采用高温固相反应法在弱还原气氛下制备了Ca2Y7.9(SiO4)6O2-0.5xFx:Eu(2+,3+)0.1(x=0～4)系列荧光粉。晶胞参数a,c和晶胞体积V均随着F-置换量的增加呈线性减小,晶胞参数a和c的变化率相近。荧光体中Eu2+和Eu3+共存,Eu2+3d5/2与Eu3+3d5/2电子结合能分别为1128.4和1136.3 eV,Eu2+的3d5/2与3d3/2的电子结合能差为28.4 eV。Eu2+和Eu3+的3d5/2态XPS峰面积比为6.9∶1。激发光谱由Eu3+的两个电荷迁移(CTS)带和f-f跃迁激发线组成,x=0,1的试样中出现了Eu2+的f-d跃迁强激发谱带。激发到Eu3+的电荷迁移态或激发Eu2+,除了来自Eu3+的5D0能级的发射之外,还观察到了5D1能级的强发射和5D2能级的弱发射,并且激发Eu2+时5D1→7F4发射强度超过5D0→7F2,没有出现Eu2+的明显发射,Eu2+对Eu3+发光起到很好的敏化作用。5DJ(J>0)高能级发射来自4f格位的Eu3+发光中心,Eu2+的敏化起关键作用。Eu3+在4f和6h两种格位的分布比为4∶6。     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Synthesis and Optical and Redox Properties of Symmetric and Asymmetric BODIPYs

Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission.     

Conformations and steric and stacking interactions of trisubstituted ureas and thioureas with alkyl and phenyl groups

The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R₂UPh type and -thioureas of the R₂TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

钒与糖代谢及糖尿病

微量元素钒作为生物体内必需元素，经证实有很重要的生理学功能，与机体糖代谢有十分密切的关系，且能降低糖尿病动物模型的高血糖，极有可能被开发为治疗糖尿病的药物。     

Ferrocene and ferrocenium modified clays and their styrene and EVA composites

In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer.     

Synthesis of Tyrosol and Hydroxytyrosol Glycofuranosides and Their Biochemical and Biological Activities in Cell-Free and Cellular Assays

Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection.