ZnGa2Se4:V3+ 光谱的理论研究

应用区分t₂和e轨道共价性的差异(包含静电部分和晶场部分)并考虑了低对称场的能量矩阵, 在考虑和忽略静电参量B₀₀的条件下, 分别研究了t₂和e轨道共价性的差异对三元半导体ZnGa₂Se₄:V ³⁺能级以及低对称分裂的影响; 计算了ZnGa₂Se₄:V ³⁺晶体的能级的低对称分裂, 并与实验值进行比较. 计算结果与实验值符合很好. 研究发现: 在对ZnGa₂Se₄:V ³⁺晶体的光学性质进行理论研究时, 在能量矩阵的静电和晶场部分同时考虑t₂和e轨道共价性的差异是非常有必要的; 晶场参量B₀₀对ZnGa₂Se₂4:V ³⁺的能级有重要影响, 因此不能忽略.     

NaBH4还原改性TiO2(B)及光催化性能研究

以TiCl₄为原料,在（CH₂OH）₂溶液中通过一步水热法制备单斜相二氧化钛[TiO₂(B)]。使用不同质量含量NaBH₄对TiO₂(B)进行还原改性,调控其内含Ti³⁺的浓度,合成了含Ti³⁺的TiO₂(B)-NaBH₄X样品。采用X射线衍射仪（X-ray diffraction,XRD）、拉曼光谱仪（Raman spectroscopy）、紫外-可见漫反射光谱仪（UV-visible diffuse reflectance spectroscopy,UV-DRS）、X射线光电子能谱仪(X-ray photoelectron spectroscopy,XPS）对材料进行表征。改性后TiO₂(B)-NaBH₄X样品保持其原有晶体结构,并未发生相变,仅有结晶度的改变。原始TiO₂(B)禁带宽度为3.15 eV,通过改性,Ti³⁺的存在改变了禁带宽度,成功地将禁带宽度降低到2.82 eV,将吸光区域扩展到可见光区域。通过可见光光催化分解水制氢与可见光降解甲基橙试验,确立了TiO₂(B)-NaBH₄3样品有最好的可见光光催化活性,产氢速率达到0.58 μmol·h^-1·g^-1,6 h降解率达到40%。     

CdS/Ru（bpy）32+电致化学发光传感器的构建及邻苯二酚的检测

基于硫化镉量子点（CdS QDs）对三联吡啶钌（Ru（bpy）₃²⁺）电致化学发光（ECL）信号的增敏作用,在电极表面滴涂CdS QDs,然后引入含有多壁碳纳米管（MWCNTs）和金纳米粒子（Au NPs）的（Ru（bpy）₃²⁺）复合物（MWCNTs-Au NPs-Ru（bpy）₃²⁺）,得到了自增强CdS/Ru（bpy）₃²⁺ECL传感器.该传感器同时包含了ECL物质Ru（bpy）₃²⁺和共反应剂CdS QDs,具有自增强特点,MWCNTs和Au NPs的存在可进一步放大传感器的信号.邻苯二酚的电极氧化产物与Ru（bpy）₃²⁺之间存在能量转移,导致ECL信号淬灭,从而实现了邻苯二酚的灵敏检测,线性响应范围为5.0×10^-9~1.0×10^-5 mol·L^-1,检出限为1.5×10^-9 mol·L^-1.该传感器用于河水中邻苯二酚的检测,结果令人满意.同时,传感器也表现出良好的重现性和稳定性.     

Pu(H2O)53+和Pu(H2O)54+ 团簇的相对论密度泛函研究

用TPSSTPSS密度泛函方法, Pu离子和H₂O分子分别采用相对论有效原子实势(RECP)和6-31g基组, 研究了Pu(H₂O)₅³⁺和Pu(H₂O)₅⁴⁺ 团簇溶剂化和非溶剂化效应中的几何结构及紫外可见吸收光谱. 计算结果表明: 水溶剂环境对Pu(H₂O)₅³⁺及Pu(H₂O)₅⁴⁺ 团簇的几何结构影响都比较明显. NBO电荷分析表明水分子与钚离子之间没有直接的电荷转移. 所研究团簇的未配对电子都占据5f轨道. 在气相及水溶剂环境下, 所研究团簇的紫外可见吸收光谱存在较大差距. 主要的吸收峰大都源于f电子之间的跃迁.     

CoFe2O4-Al2O3复合材料的制备及其在含日落黄废水处理中的应用

制备了铁酸钴-氧化铝（CoFe₂O₄-Al₂O₃）复合材料,并采用扫描电子显微镜（SEM）、X射线衍射（XRD）、比表面积和孔径分析仪对多孔CoFe₂O₄-Al₂O₃复合材料的物相和形貌进行了分析. 利用制备的CoFe₂O₄-Al₂O₃复合材料活化过硫酸氢钾（PMS）来降解废水溶液中的日落黄（SY）,通过研究CoFe₂O₄-Al₂O₃材料制备过程中Co²⁺,Fe³⁺和Al³⁺的物质的量之比、煅烧温度和时长对材料催化性能的影响,发现Co²⁺,Fe³⁺和Al³⁺的最佳物质的量之比为1:2:12,最佳煅烧温度为400 ℃和最佳煅烧时长为3 h. 对采用在最优条件下制得的CoFe₂O₄-Al₂O₃复合材料作为催化剂,PMS氧化降解含日落黄废水进行研究,考察了pH值、温度、不同体系、PMS用量、CoFe₂O₄-Al₂O₃材料用量和一些阴离子对日落黄降解的影响. 结果表明：在pH=7,温度为55 ℃条件下,用0.1 g催化剂和0.125 g PMS能使100 mL质量浓度为0.6 g·L^-1的日落黄溶液在30 min内降解率达到99.5%. 同时,碳酸氢根负离子（HCO₃^-）和硝酸根负离子（NO₃^-）的加入抑制了日落黄的降解,而Cl^-则能促进日落黄的降解. 此外,在进行4次循环使用后,CoFe₂O₄-Al₂O₃仍表现出很好的催化性能,日落黄去除效果仍能达到90%以上.     

一种新型发红光材料SrGdGa3O7:Eu 3+及其性质研究

 采用高温固相法合成了发红光的荧光粉SrGdGa₃O₇:Eu³⁺。漫反射光谱和激发光谱中Eu^₃₊的电荷迁移带、Eu³⁺离子f→f跃迁以及Gd³⁺离子^8S_7/2→⁶I_7/2的跃迁相互吻合;监测Eu³⁺离子的特征发射,激发谱中有Gd^3+离子的激发线表明存在Gd³⁺→Eu³⁺的能量传递。发射光谱中以⁵D₀→⁷F₂ 跃迁为主,表明Eu³⁺离子所占据的晶体学格位没有对称中心的Cs格位。根据低温下的发射光谱计算了⁷F₁ 和^7F₂ 能级完全解除简并后的每个分裂能级的位置。Eu³⁺的发射发生明显的温度猝灭现象,同时发射谱线的分辨率也逐渐降低。Eu³⁺离子的⁵D₀→ ⁷F₂ 跃迁在不同温度下的荧光衰减曲线相似;随着温度的升高,荧光发射强度衰减越快,但是仍然处于毫秒数量级;⁵D₀ → ⁷F₂ 跃迁是宇称和自旋禁阻的跃迁,所以荧光衰减时间比较长。     

Al2O3/WO3/ZrO2催化剂的制备及在酯交换反应中的研究

以松木为模板,采用模板法将不同含量的Al₂O₃添加到WO₃/ZrO₂复合氧化物中,采用X射线衍射、BET比表面积分析、拉曼光谱和NH₃等温吸附测试等手段对其进行表征,以评估其改进结果。将Al₂O₃/WO₃/ZrO₂催化剂应用到甲醇与乌桕油（非食用油）的酯交换反应中,在其他反应条件相同,Al₂O₃质量分数为3%时,生物柴油最高产率达到83.1%。结果表明：添加Al₂O₃稳定了ZrO₂的四方相结构,使得催化剂比表面积更大、孔数量增加;模板法制备的催化剂孔径分布均匀,WO₃呈高度分散无定型状态;引入Al₂O₃增加了WO₃/ZrO₂催化剂的中强酸性,对弱酸性和强酸性无明显改变。     

BLim1/2+(m=6、7)团簇的结构及储氢性能的研究

为开发新型储氢材料提供更为丰富的理论基础,采用B3LYP泛函在6-311++G(d,p)基组水平上对BLi₆⁺超碱团簇和BLi₇²⁺超碱土团簇的稳定性结构、电荷分布等方面进行理论研究,进而研究团簇的储氢性能。结果表明：两个离子团簇均比它们所对应的中性团簇均具有较高的动力学稳定性。两个离子团簇中的每个Li原子同时有效吸附2个氢分子,BLi₆⁺团簇中氢分子在团簇表面平均吸附能为0.969~2.162kCal/mol,储氢质量分数达31.56wt%。而BLi₇⁺团簇中氢分子在团簇表面平均吸附能为1.764~3.714kCal/mol,储氢质量分数达32.21wt%。它们的储氢性能表明BLi₆⁺团簇和BLi₇²⁺团簇均有望成为良好的储氢媒介。     

高密度TeO2-Gd2O3-WO3闪烁玻璃颜色调控的研究

采用传统高温熔融法制备了不同玻璃组成的碲钆钨酸盐玻璃（TeO₂-Gd2O₃-WO₃），通过紫外—可见分光光度计研究了碲钆钨酸盐玻璃在分别固定Gd₂O₃浓度为10 mol%（xTeO₂-10Gd₂O₃-(90-x)WO₃）和20 mol%（yTeO₂-20Gd₂O₃-(80-x)WO₃）时，玻璃光学透过性随WO₃浓度和熔制温度的依赖关系，并借助光碱度理论进行了解释。结果表明，xTeO₂-10Gd₂O₃-(90-x)WO₃玻璃随着玻璃中WO₃浓度由0 mol%增加到60 mol%，碲钆钨酸盐玻璃的颜色由浅黄（低于20 mol%）逐渐变为深棕色（40 ~ 60 mol%）。另一方面，yTeO₂-20Gd₂O₃-(80-y)WO₃（y=40）玻璃随着玻璃熔制温度从1000 ℃升高到1200 ℃，碲钆钨酸盐玻璃的颜色从浅黄（低于1050 ℃），变为深棕色（1100 ℃）甚至黑色（1200 ℃）。这种颜色变化是由于随WO₃浓度升高，玻璃的光碱度单调增加，导致玻璃截止吸收边红移及玻璃光学透过率降低的共同作用效果。     

TiO2/CB-NiCo2O4修饰玻碳电极的制备及其对葡萄糖的电化学测定

利用低温下的水化学生长法合成了镍钴氧化物（NiCo₂O₄）纳米针,因其自组装而表现出立方晶相,再用二氧化钛/炭黑（TiO₂/CB）对NiCo₂O₄表面进行了改性,合成了TiO₂/CB-NiCo₂O₄复合纳米材料.用X射线光电子能谱仪（XPS）、扫描电子显微镜（SEM）、能量色散X射线光谱仪（EDX）图谱对材料的形貌进行了表征,运用循环伏安法（CV）、时间-电流（i-t）曲线法考察了TiO₂/CB-NiCo₂O₄修饰玻碳电极的电化学行为.实验发现：TiO₂/CB-NiCo₂O₄修饰电极对葡萄糖的氧化有良好的电催化性能,其线性范围为0.001~1.780 mmol·L^-1,检测限为0.53 μmol·L^-1（信噪比S/N=3）.将该法用于实际样品中葡萄糖的测定,结果令人满意.     

The concentration quenching characteristics of 5D3-7FJ and 5D4-7FJ (J=0―6) transitions of Tb3+ in YBO3:Tb3+ phosphor

The photoluminescence quenching behaviors of ^5D3-^7Fj and ^5D4-^7Fj （J = 0—6） transitions of Tb^3＋ in YBO3：Tb under 130—290 nm excitation were systematically investigated. The results revealed that the quenching concentrations of both ^5D3-^7Fj and ^5D4-^7Fj transitions of Tb^3＋ in YBO3：Tb were mainly dependent on excitation wavelength. Particularly, the quenching concentrations of ^5D4-^7Fj transitions of Tb^3＋ under 130—290 nm excitation were correlated with excitation bands of YBO3：Tb. The quenching concentrations of ^5D3-^7Fj transitions remained at low concentration （2%） under 186—290 nm excitation and then increased gradually with energy of incoming excitation photon when excited at 130—186 nm. This dependence should be involved in their excitation mechanisms and quenching pathway in particular excitation region.[第一段]     

Preparation and luminescence characteristics of Sr3SiO5：Eu^2＋ phosphor for white LED

The Sr3SiO5：Eu^2＋ phosphor was synthesized by high temperature solid-state reaction. The emission spectrum of Sr3SiO5：Eu^2＋ shows two bands centered at 487 and 575 nm, which well agree with the theoretic values of emission spectrum. The excitation spectrum for 575 nm emission center has several excitation bands at 365, 418, 458 and 473 nm. And the results show that the emission spectrum of Sr3SiO5：Eu^2＋ is influenced by the Eu^2＋ concentration. The relative emission spectra of the white-emitting InGaN-based YAG：Ce^3＋ LED and Sr3SiO5：Eu^2＋ LED were investigated. The results show that the color development of InGaN-based Sr3SiO5：Eu^2＋ is better than that of InGaN-based YAG：Ce^3＋, and the CIE chromaticity of InGaN-based Sr3SiO5：Eu^2＋ is （x=0.348, y=0.326）.     

Mg2+-induced LHC II aggregation in thylakoid membrane

Mg²⁺-induced changes in 77K fluorescence spectra of wheat thylakoid membranes were analyzed by a Gaussian deconvolution program. All spectra were fitted well with 7 Gaussian sub-bands. The sub-band areas for the LHC H macroaggregate (F₆₉₉) and PS II (F₆₈₅ and F₆₉₅) were increased and those for the LHC II trimer (F₆₈₁) and PS I (F₇₂₉ and F₇₄₀) were decreased by Mg²⁺. Moreover, it was found that the sub-band area ratio for F₆₉₉ over F₆₈₁ was dramatically enhanced by Mg²⁺ by 1.72 times. It was concluded that the LHC II trimer in thylakoid membranes could be aggregated and transformed into its macroaggregate by Mg²⁺ on a large scale. The possible implication of the Mg²⁺-induced LHC II aggregation was also discussed.     

Theoretical study of partial oxidation of ethylene by vanadium trioxide cluster cation

Density functional theory （DFT） study of reaction between vanadium trioxide cluster cation （VO3^＋） and ethylene （C2H4） to yield VO2^＋ ＋ CH3CHO （acetaldehyde） and VO2CH2^＋ ＋ HCHO （formaldehyde） is carried out. Structures of all reactants, products, intermediates, and transition state in the reaction have been optimized and characterized. The results show unexpected barriers in the reaction due to the existence of a η^2-O2 moiety in the ground state structure of VO3^＋. The initial reaction steps combining ethylene adsorption, C=C activation and O-O cleavage are proposed as rate limiting processes. Comparison of reactions of VO3^＋ ＋ C2H4 with VO3 ＋ C2H4 and VO2^＋ ＋ C2H4 in the previous studies is made in detail. The results of this work may shed light on the understanding of C=C bond cleavage in related heterogeneous catalysis.     

Zn2+对果蝇生育力和寿命及抗氧化能力的影响

为了研究Zn~(2+)对果蝇生育力和寿命及抗氧化能力的影响。以黑腹果蝇(Drosophila melanogaster)为研究动物,用生存实验来考查不同浓度的Zn~(2+)处理果蝇,研究果蝇F1-F4代生育力和寿命的变化,雌、雄果蝇数量的变化,抗氧化酶SOD、CAT的活力及MDA含量的变化。结果显示:添加Zn~(2+)浓度为1.0 g/mL可以使F1-F4代雌、雄果蝇世代生育力增强,寿命延长,而在Zn~(2+)浓度为2.0×10-3g/mL时果蝇体内MDA含量大量积累,SOD和CAT活性急剧降低,使果蝇提前衰老、死亡并且降低或丧失生殖能力,而Zn~(2+)对果蝇性别分化影响不大,总体接近于1:1。因此,适当浓度的Zn~(2+)可以延长果蝇寿命,增强其生殖力,提高抗氧化能力。     

Potential red-emitting phosphor GdNbO4:Eu3+,Bi3+ for near-UV white light emitting diodes

A red-emitting phosphor GdNbO₄:Eu³⁺,Bi³⁺ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction (XRD), particle size analyzer and fluorescence spectrometer. The single phase of GdNbO₄:Eu³⁺,Bi³⁺ was obtained at 1150°C and the average particle diameter was about 2.30 ??m. Excitation and emission spectra reveal that the phosphor can be efficiently excited by ultraviolet (UV) light (394 nm) and emit the strong red light of 612 nm due to the Eu³⁺ transition of ⁵D₀??⁷F₂. The optimum content of Eu³⁺ doped in the phosphor GdNbO₄:Eu³⁺ is 20mol%. The phosphor Gd_0.80NbO₄:0.20Eu³⁺,0.03Bi³⁺ shows much stronger photoluminescence intensity and better chromaticity coordinates (x=0.642, 0.352) than GdNbO₄:Eu³⁺. It is confirmed that Gd_0.80NbO₄:0.20Eu³⁺,0.03Bi³⁺ is a potential candidate for near-UV chip-based white light emitting diodes.     

Effects of Yb^3＋ codoping on visible and near infrared emissions of Er^3＋-Yb^3＋ codoped Al2O3 powders by the sol-gel method

The 0.1 mol% Er^3＋ and 0-2 mol% Yb^3＋ codoped Al2O3 powders were prepared by the sol-gel method, and the phase structure, including only two crystalline types of doped Al2O3 phase, γ-（Al,Er, Yb）2O3 and θ-（Al,Er, Yb）2O3, was detected at the sintering temperature of 1000℃. The visible and near infrared emissions properties depended strongly on the Yb^3＋ codoping, and the corresponding maximal peak intensities centered at about 523, 545, 660 and 1533 nm were obtained respectively for the 0.1 mol% Er^3＋ and 0.5 mol% Yb^3＋ codoped Al2O3 powders, which were composed of θ-（Al,Er,Yb）2O3 and a small amount of γ-（Al,Er, Yb）2O3 phases. The two-photon absorption process was responsible for the visible up-conversion emissions, and the one-photon absorption process was involved in the near infrared emissions of the Er^3＋-yb^3＋ codoped Al2O3 powders.     

Y2O2S:Eu3+,Zn2+,Ti4+荧光体的缺陷及红色长余辉发光性质

采用高温固相法合成了红色长余辉材料Y2O2S:Eu3+,Zn2+,Ti4+,实现了余辉发光中心和缺陷中心之间的能量传递。通过XRD、荧光发射和激发光谱、余辉发射光谱与衰减曲线、色坐标和热释光谱测试手段对Y2O2S:Eu3+,Zn2+、Y2O2S:Eu3+,Ti4+、Y2O2S:Eu3+,Zn2+,Ti4+和Y2O2S:Eu3+,Mg2+,Ti4+进行了结构与性能的表征,发现其荧光发射与余辉发射基本一致,红色余辉发光主峰位于625 nm附近,来源于Eu3+的5D0→7F2跃迁发射。相比而言,Y2O2S:Eu3+,Zn2+,Ti4+余辉发光性能最好,可持续1.5 h左右。