共沉淀法制备Y_2O_2S∶Eu^(3+),Mg^(2+),Ti^(4+)红色长余辉材料

用共沉淀法制备了Y2O2S∶Eu3+,Mg2+,Ti4+红色长余辉材料。测量了材料的电子显微形貌、晶体结构和发射光谱。通过与固相法制备的Y2O2S∶Eu3+,Mg2+,Ti4+长余辉材料比较,发现两种方法都可以制备粒度基本相同的纯相Y2O2S基质晶体,但共沉淀法样品的颗粒结构更松散。研究了Eu3+浓度对两种方法制备样品的谱线发射强度的影响,通过比较共沉淀法和高温固相法制备的样品中Eu3+的5D1→7F3较高能级跃迁的587.6 nm谱线强度随Eu3+浓度的变化,发现共沉淀法更有利于Eu3+均匀进入Y2O2S基质晶格而形成有效的发光中心。

Ti^(4+)掺杂改善锂离子电池正极材料LiFePO_4的电化学性能研究

采用固相法掺杂钛合成了Li1-yTiyFePO4,研究了原料钛的掺杂量、焙烧温度和焙烧时间对锂离子电池正极材料Li1-yTiyFePO4电化学性能的影响。通过正交实验[L9(33)]确定合成橄榄石型Li1-yTiyFePO4的最佳工艺为:掺杂Ti4+量为1%(摩尔分数),焙烧温度为700℃,焙烧时间为16 h。经实验验证,优化后的合成工艺有利于提高锂离子电池正极材料的电化学性能。

温和条件下制备掺Ti^(4+)磷酸铁的研究

为提高LiFePO_4的电性能,将LiFePO_4掺杂工序前置至磷酸铁的合成阶段,在磷酸铁的制备过程中添加Ti^(4+)制备掺Ti^(4+)磷酸铁。结果显示:Ti^(4+)可以取代Fe^(3+)进入磷酸铁晶格中;Ti^(4+)掺入量的增加将会影响磷酸铁晶体的晶面间距,使得(002)晶面间距显著增大,且当Ti^(4+)掺杂量为0.5%时,对磷酸铁晶面间距影响最大;晶面间距增大,有利于锂离子的脱嵌,磷酸铁锂的电性能增强;掺Ti^(4+)的磷酸铁较未掺杂时,在600℃时出现了明显的晶型转变的吸热峰;掺Ti^(4+)的磷酸铁的比表面积较未掺杂磷酸铁的比表面积显著提高,这说明掺Ti^(4+)磷酸铁的化学活性提高,有利于提高磷酸铁锂的电性能;采用掺Ti^(4+)磷酸铁为原料制备的磷酸铁锂,当钛含量为0.5%时,放电容量最高,即电容为0.2 C时,放电容量为160 m Ah/g。

Ti^(4+)的掺入对Y_2O_2S:Eu^(3+),Mg^(2+),Ti^(4+)陷阱分布和余辉性能的影响

用高温固相法制备了不同Ti4+掺杂量的红色长余辉材料Y2O2S:Eu3+,Mg2+,Ti4+,其X射线衍射分析、发射光谱和激发光谱均不受Ti4+掺杂量改变的影响.测量了Ti4+掺杂量不同的样品的热释光谱,随着Ti4+掺杂量的增加,热释光的峰值强度先增强后减弱,有了很大的变化;用PeakFit软件以一般阶动力学模型对Ti与Y2O2S的物质的量比分别为0.5%,2.5%和8.0%的样品进行了热释光曲线拟合,得出了它的单峰曲线并计算了与其对应的陷阱参数.陷阱分布表明:当Ti掺杂量为2.5%时,有利于合适深度陷阱的大量形成,从而使材料的发光和余辉性能得到了很大的提高.

Ti^(3+):ZrSiO_4中Ti^(3+)中心g因子研究

锆英石(ZrSiO4)的热膨胀系数和导热系数较低,抗震性能和化学稳定出色,近年来,逐渐受到人们的重视.通 过引入平均因子和3d1电子在D2d晶场的g因子公式,研究了Ti3+:ZrSiO4中Ti3+中心EPRg因子,得到的结果与实验值基本 稳合.

Y_2O_2S∶Eu^(3+),Mg^(2+),Ti^(4+)长余辉材料制备中烧结条件和助熔剂的影响

采用高温固相法合成了Y2O2S∶Eu3+,Mg2+,Ti4+红色长余辉材料。通过X射线衍射分析和扫描电镜测试技术研究了样品的晶体结构和颗粒的大小、形貌,分析了有助于晶体颗粒生长的烧结温度、气氛以及助熔剂对它的影响,还对荧光体的发光光谱、相对亮度、余辉性质进行了研究。结果表明,制备得到的Y2O2S∶Eu3+,Mg2+,Ti4+红色长余辉材料体系相态纯净,有较完整和均匀的晶形,完整的晶体结构有利于提高荧光体的发光性质。制备中合适的烧结温度为1 150℃,要选择弱还原气氛。加入L i3PO4可以使晶体颗粒的晶型完整,粒径增大,并且粒度分布较窄。

Ti^(3+)自掺杂TiO_2纳米管/g-C_3N_4复合材料的制备及可见光催化性能

以低温退火制得的TiO_2纳米管和三聚氰胺为原料,经过一步煅烧制备Ti^(3+)自掺杂TiO_2纳米管/g-C_3N_4复合材料.采用热重分析(TGA)、X-射线衍射(XRD)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)和紫外-可见漫反射光谱(UV-Vis DRS)对Ti^(3+)自掺杂TiO_2纳米管/g-C_3N_4复合材料的热稳定性、组成、结晶性、形貌、化学价态和光学性能等进行了表征.结果表明,将H_2Ti_3O_7预处理后再与三聚氰胺混合热处理,产物是Ti^(3+)自掺杂TiO_2纳米管/g-C_3N_4复合材料,而未经预处理的H_2Ti_3O_7与三聚氰胺混合后热处理得到的是Ti^(3+)自掺杂TiO_2纳米颗粒/g-C_3N_4复合材料.罗丹明B((RhB)水溶液为模拟废水,以300 W氙灯(λ>420 nm)为光源,研究了所得产物的可见光催化降解性能.结果表明,与纯的TiO_2和g-C_3N_4相比,Ti^(3+)自掺杂TiO_2纳米管/g-C_3N_4复合材料具有最佳的光催化降解性能,光催化降解80 min时,对RhB的降解率达98.4%.这得益于Ti^(3+)及TiO_(2-x)纳米管与g-C_3N_4构筑的异质结提高了材料对可见光的响应性能,加快了光生电子的传输和分离,降低了电子和空穴的复合几率.

水热法制备Y_2O_2S∶Dy^(3+),Mg^(2+),Ti^(4+)白色长余辉微纳米材料及发光性能

采用水热法制备了白色长余辉微纳米发光材料Y2O2S∶x Dy3+,Mg2+,Ti4+(x=0.5%,1.0%,1.5%,2.0%,2.5%),利用X射线粉末衍射(XRD)、扫描电镜(SEM)、激发和发射光谱、色度坐标、余辉曲线和热释光谱对样品进行表征。结果表明:煅烧后,样品的形貌为颗粒状,其粒径在150~250 nm之间;在359 nm的紫外光激发下,样品在488 nm和579 nm处有两个很强的发射峰,它们分别对应于Dy3+的蓝色跃迁(4F9/2→6H15/2)和黄色跃迁(4F9/2→6H13/2),适当比例的黄光和蓝光混合可以产生白光;当Dy3+浓度为2.0%(摩尔分数)时,样品的余辉性能最佳,用254 nm的低压汞灯照射10 min后,余辉时间可达到3600 s(≥1 mcd/m2)以上,与同样温度下高温固相法或溶胶凝胶法所制备样品的相比,其余辉性能得到了很大改善。

Characterization of Y_2O_2S∶Eu ^(3+), Mg^(2+), Ti^(4+) Long-Lasting Phosphor Synthesized by Flux Method

Long-lasting phosphor Y2O2S ： Eu^3＋ , Mg^2＋ , Ti^4＋ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased with the increase of Eu2O3 content in Y2O2S： Eu^3＋ （0.01 ≤ x ≤0.10）. On the other hand, the change of unit cell parameter a is not linear dependence. In the Y2O2S： Eu^3 ＋ crystal structure, Eu^3＋ ions only replaced Y^3 ＋ ions＇ places in which it posited center position of c axis. With the increase of Eu2O3 content, the position of the strongest emission peak changed from 540 nm （5D1→^ 7F2 transition） to 626 nm （^5Do→^7TF2 transition）, and the maximum intensity was obtained when x = 0.09 in Y2O2S： Eu^3＋ （0.01 ≤x ≤0.10）. This is due to the environment of trivalent europium in the crystal structure of Y2O2S. Doping with Mg^2＋ or Ti^4＋. ions alone cannot get the good long-lasting afterglow effect, whereas co-doping with Mg^2 ＋ and Ti^4 ＋ ions and excited with 365 nm ultraviolet light, a strong thermoluminesence peak appeared, red and orange long-lasting phosphorescence （LLP） was also observed and the phosphorescence lasted nearly 3 h in the light perception of the dark-adapted human eye （0.32 mcd·m^-2）. Thus the LLP mechanism was analyzed.

Co-Precipitation Synthesis and Spectral Characteristics of Long Afterglow Phosphor Y_2O_2S:Sm^(3+), Mg^(2+), Ti^(4+)

Y2O2S：Sm^3＋, Mg^2＋, Ti^4＋ phosphor was synthesized by co-precipitation method. The crystalline structure of all synthesized phosphors was investigated by XRD. The result showed that all synthesized phosphors had a hexagonal crystal structure, which was the same as Y2O2S. The emission spectrum and excitation spectrum were measured, and the effect of Sm^3 ＋ molar ratio on the spectra was discussed. The emission spectra of the phosphors showed three emission peaks due to typical transitions of Sm^3 ＋ （4G5/2→6HJ ,J = 5/2, 7/2, 9/2）, and the emission peaks at 606 nm was stronger than others. With the increase of Sm^3 ＋ molar ratio, the emission intensity was strengthened. The excitation peaks were ascribed to the representative energy transition 4f→4f of Ti^4＋ phosphor prepared by co-precipitation method was Sm^3＋ ions. The results indicated that the Y2O2S ： Sm^3＋ , Mg^2＋ , an efficient long afterglow phosphor.

Insights into the enhanced structure stability and electrochemical performance of Ti^(4+)/F^(-) co-doped P2-Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2) cathodes for sodium ion batteries at high voltage

P2-Na_(0.67)N_(i0.33)Mn_(0.67)O_(2)is considered as a promising cathode material for sodium-ion battery (SIBs)because of its high capacity and discharge potential.However,its practical use is limited by Na^(+)/vacancy ordering and P2-O2 phase transition.Herein,a Ti^(4+)/F^(-) co-doping strategy is developed to address these issues.The optimal P2-Na_(0.67)Ni_(0.33)Mn_(0.37)Ti_(0.3)O_(1.9)F_(0.1) exhibits much enhanced sodium storage performance in the high voltage range of 2.0–4.4 V,including a cycling stability of 77.2%over 300cycles at a rate of 2 C and a high-rate capability of 87.7 m Ah g^(-1) at 6 C.Moreover,the P2-Na_(0.67)Ni_(0.33)Mn_(0.37)Ti_(0.3)O_(1.9)F_(0.1) delivers reversible capacities of 82.7 and 128.1 m Ah g^(-1) at-10 and 50℃ at a rate of 2 C,respectively.The capacity retentions over 200 cycles at-10℃ is 94.2%,implying more opportunity for practical application.In-situ X-ray diffraction analysis reveals that both P2-O2 phase transitions and Na^(+)/vacancy ordering is suppressed by Ti^(4+)/F^(-) co-doping,which resulting in fast Na^(+) diffusion and stable phase structure.The hard carbon//P2-Na_(0.67)Ni_(0.33)Mn_(0.37)Ti_(0.3)O_(1.9)F_(0.1) full cell exhibits a high energy density of 310.2 Wh kg^(-1) and remarkable cyclability with 82.1%retention after 300 cycles at 1 C in the voltage range of 1.5–4.2 V.These results demonstrate that the co-doping Ti^(4+)/F^(-) is a promising strategy to improve the electrochemical properties of P2-Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2),providing a facile tactic to develop high performance cathode materials for SIBs.

Thin Layer Chromatographic Study of Bauxite and Quantitative Estimation of Co-Existing Al^(3+), Fe^(2+) and Ti^(4+)

Thin layer chromatography in combination with spectrophotometry and titrimetry has been used to evaluate chromatographic characteristics of bauxite constituents. The retention behaviors of four major constituents (Al 3+ , Fe 2+ , Ti 4+ , Si 4+ ) in bauxite mineral have been examined on plain and modified layers of silica gel G, silica gel H and cellulose with mobile phases containing aqueous sodium chloride, formic acid and hydrochloric acid. Ternary separation of Al-Fe-Ti was achieved on chromatographic plates made of silica gel H. The pH effect and presence of impurity elements in samples, nature of stationary phases on the ternary separation and detection limits of bauxite constituents were studied. Silicon in bauxite was detected on cellulose plates. Quantitative determinations of Al 3+ , Fe 2+ and Ti 4+ on silica gel H impregnated with sodium formate layers were achieved by titrimetry and spectrophotometry.

Influence of Ti^(4+) doping on hyperfine field parameters of Mg_(0.95)Mn_(0.05)Fe_(2-2x)Ti_(2x)O_4(0≤x≤0.7)

The mixed spinel ferrite system Mg0.95Mn0.05Fe2-2xTizxO4 （0 ≤x ≤ 0.7） was synthesized by the conventional solid-state reaction technique. The effect of Ti^4＋ doping was studied by using the Moessbauer spectroscopy measurements at room temperature. From the analysis of the Moessbauer spectra, it is observed that s-electron density, electric field gradient （EFG）, quadrupole coupling constant （QCC） and the net hyperfine magnetic fields acting on the Moessbauer nuclei-FeA^3＋ and FeB^3＋ change with the increase of Ti^4＋ doping in Mg0.95Mn0.05Fe2O4. The hyperfine magnetic field decreases with the increase of Ti^4＋ doping.

X-RAY FLUORESCENCE SPECTRA ANALYSIS ON THE STRUCTURE AROUND Ti^(4+) OF BaO-SiO_2-B_2O_3-TiO_2 SYSTEM GLASSES

The structure around Ti^(4+) in Bao-SiO_2 -B_2O_3-TiO_2 had been studied by X-ray fluorescence spectra. The results show that the Ti^(4+) mainly exists in the [TiO_4] and enters the network of [SiO_4]. [TiO_4] has the tendency to change to [TiO_6] with the increase of TiO_2 con-tent. When the TiO_2 content increases to about 20mol% the tendency reaches its maximum.

氮肥和钛离子对燕麦光合生理和农艺性状的影响

为提高植物对氮素的吸收利用效率,本试验以尿素和钛离子为影响因子,采用完全随机试验设计,通过测定分析燕麦净光合速率、水分利用效率等光合生理指标以及株高、分蘖、草产量等农艺性状,研究不同施肥处理对燕麦光合生理和农艺性状的影响。结果表明,氮肥显著提高了燕麦叶片气孔导度、胞间CO_(2)浓度、鲜草产量、干草产量、茎重、叶重以及叶面积指数(P<0.05),对燕麦的净光合速率的提高亦具有一定的促进作用;钛离子显著提高了燕麦净光合速率、鲜草产量、叶面积指数(P<0.05);氮肥和钛离子配合施用对燕麦的光合生理和生产性能具有协同效应,施肥方式为撒施90 kg/hm^(2)尿素+叶面喷施800倍钛离子稀释液(Ti^(4+)约4.38mg/L)时,能让燕麦产量与光合性能达到最优,适宜在燕麦牧草生产上推广应用。

定量磷酸化蛋白质组解析17β-雌二醇致死效应的细胞调控过程

17β-雌二醇(E2)是人体内一种重要的内分泌激素,在生理浓度下(0.2~1.0 nmol/L)对生殖系统、乳腺等靶器官的生长发育起着重要的调节作用。但很多研究表明,高剂量(μmol/L~mmol/L)的E2能够诱导肿瘤组织消退和细胞凋亡,其具体调控机制尚不明确。本工作聚焦于高剂量(μmol/L)的E2致死效应,首先分析了μmol/L水平的E2对HeLa细胞表型的影响,发现在1~10μmol/L下E2以浓度依赖的形式抑制HeLa细胞增殖,并诱导HeLa细胞发生死亡,其中,用5μmol/L E2处理2天后可使约74%的HeLa细胞增殖受到抑制,并引起约50%的HeLa细胞死亡。在此基础上,为了探究高剂量E2诱导细胞死亡的内在调控过程,将基于固相萃取(SPE)的固定化钛离子亲和色谱技术(Ti 4+-IMAC)与基于数据非依赖采集模式(DIA)的蛋白质组定量技术结合,用于筛选HeLa细胞内参与高剂量(μmol/L)E2致死效应调控过程的磷酸化位点。最终,在5μmol/L E2和二甲基亚砜(DMSO)处理的HeLa细胞中共鉴定到超过10000个磷酸化位点;t检验分析发现,在E2处理后,有924个磷酸化位点(对应599个蛋白质)的丰度发生了显著变化(显著性水平(p)<0.01,|log 2(倍数变化)|≥1),推测其可能参与调控E2致死效应过程。此外,有453个磷酸化位点(对应325个蛋白质)仅单独发生在E2或DMSO处理后的HeLa细胞样品中,表明这些磷酸化位点在E2处理后发生了磷酸化或去磷酸化,也可能参与E2致死效应的调控过程。分别对以上两种方式筛选的E2调控的磷酸化蛋白质进行富集分析,发现这些磷酸化蛋白质主要参与细胞分裂、核糖体/核质转运、信使核糖核酸(mRNA)加工/剪接及转录等过程,表明高剂量的E2可能通过调控核糖体及mRNA加工等过程影响蛋白质转录,进而诱导细胞发生死亡。此外,我们发现表皮生长因子受体(EGFR)和丝裂原活化蛋白激酶(MAPK)家族蛋白(包括MAPK1、MAPK4和MAPK14)上多个磷酸化位点的修饰水平在高剂量E2处理后发生了明显变化,表明EGFR和MAPK信号通路可能在雌激素诱导的细胞死亡中起着重要调控作用。本实验得到的磷酸化蛋白质组定量结果有助于进一步了解高剂量E2的内在调控过程,为后续解析高剂量E2的作用机制及疾病的治疗提供了参考。

Ti4+掺杂Fe位对CuFeO2陶瓷材料结构和介电性能的影响

以CuO,Fe2O3和TiO2为主要原料,采用固相反应法制备了CuFe1-xTixO2(0≤x≤0.08)陶瓷系列样品,对所得样品的结构、形貌和介电性能进行了表征和分析,并利用内部阻挡层模型(IBLC)对样品的微观结构与介电性能的关联规律进行了物理解释.结果表明,掺杂样品均具有单相铜铁矿结构;适量的Ti^4+掺杂能够促进铜铁矿CuFeO2陶瓷样品的晶粒生长,而较大浓度的Ti^4+掺杂则会对铜铁矿CuFeO2陶瓷样品的晶粒生长有明显的抑制作用,同时会破坏较为致密的晶体形貌;未掺杂及少量Ti^4+掺杂(x=0.005和0.01)样品展现出室温巨介电性能,适当掺杂Ti^4+可以有效提高体系的介电性能;IBLC模型可以解释Ti^4+掺杂CuFeO2样品的介电机理,即CuFeO2陶瓷体系的微观形貌能明显影响体系的巨介电性能.

基于Ti^(4+)-IMAC富集的分枝菌酸小杆菌深度覆盖磷酸化蛋白质组研究

【目的】本研究以分枝菌酸小杆菌(Mycolicibacterium smegmatis)为研究对象,探索适于原核微生物理想的磷酸化富集方法。【方法】我们比较了二氧化钛(TiO_(2))、Fe^(3+)-NTA和Ti^(4+)螯合在磷酸酯修饰的固相微球(Ti^(4+)-IMAC)3种不同富集方法磷酸化肽段的富集效率,并用不同分辨率的质谱仪评估富集稳定性。【结果】Ti^(4+)-IMAC富集效率最高,磷酸化位点数是TiO_(2)或Fe^(3+)-NTA方法的7倍以上;TiO_(2)和Fe^(3+)-NTA方法富集到的磷酸化位点数相差不大,与已报道的用TiO_(2)方法富集的磷酸化位点数目接近。Ti^(4+)-IMAC富集结果稳定性很好,高分辨率Lumos质谱仪鉴定到的磷酸化位点数是Velos的2.6倍。【结论】本研究较高效地实现了分枝菌酸小杆菌磷酸化事件的鉴定,共鉴定到2280个磷酸化蛋白、10880个磷酸化肽段及4433个可信磷酸化位点,有望用于其他微生物的磷酸化蛋白质组学研究。

Ce-doped MIL-125-NH_(2)coupled Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators for thermo-enhanced photocatalytic oxidative desulfurization

Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene(DBT)under mild reaction conditions.The 1.0 mol%Ce/MIL-125-NH_(2)catalyst achieved 100%sulfur removal within 22 min at 30℃ under visible light illumination,which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling.The valence transformation of Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators could not only expose abundant Lewis acid sites,but also promote the separation and transfer of photogenerated charges.In addition,increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance.Additionally,a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH_(2),demonstrating the great potential of thermal energy to promote the desulfurization activity.

Ti^＋离子和C2H4分子自旋禁阻反应中C-H键活化机理的理论研究

用密度泛函B3LYP方法,研究了二重态和四重态势能面自旋禁阻反应Ti+(4F,3d24s1)+C2H4→TiC2H2+(2A2)+H2的微观机理.通过自旋-轨道耦合的计算讨论了势能面交叉点和可能的自旋翻转过程.中间体IM1-4B2处,四重态和二重态间的旋-轨耦合值为59.3cm-1.自旋多重度必将发生变化,从四重态系间穿越到二重态势能面形成共价型复合物IM1-2A1,同时导致四重态势能面的势垒明显降低.到插入中间体IM2后,二重态势能面上有两条不同的反应路径,即分步和协同路径,后者在二重态势能面上得到放热产物TiC2H2+(2A2)+H2具有较低的活化势垒,4.52kcal/mol,其主反应路径为:Ti++C2H4→4IC→IM1-4B2→4,2ISC→IM1-2A1→[2TSins]→IM2-2A″→[2TSMCTS]→IM5→TiC2H2+(2A2)+H2.