LaBa2VO6∶Eu3+红色荧光粉的制备及其发光性能

采用改进高温固相法合成了Eu3+掺杂的LaBa2VO6红色荧光粉,用X-射线衍射仪和荧光分光光度计对样品进行了表征.结果表明:煅烧温度为900℃时,晶型形成比较完全,Eu3+成功掺入LaBa2 VO6晶格中;荧光强度随着Eu3+掺杂浓度的升高先增强后减弱,Eu3+的最佳掺杂浓度(Eu3+取代La3+的摩尔百分比)为11％;用466nm激发光源激发样品显示出强616nm红光发射.该荧光粉与蓝光LED相匹配,适合用于蓝光转换型红色荧光粉.     

稀土离子掺杂硼酸铝荧光材料的制备及发光性能的研究

采用高温固相法,在900～1 300℃范围内煅烧3h,合成Eu~(3+)和Tb~(3+)离子掺杂的硼酸铝系列荧光粉。用X射线粉末衍射仪(XRD)和荧光分光光度计对合成样品进行物相结构和荧光性能表征。结果表明,在合成温度范围内,可得到两种不同结构的稀土离子掺杂硼酸铝荧光粉Al18-xMxB4O33和Al4-xMxB2O9(M=Eu、Tb),物相结构和稀土离子的掺杂浓度对样品的发光性能均有显著影响。     

熔盐法制备CaTiO3∶Pr^3＋荧光粉及其发光性能的研究

以CaCl2为熔盐,采用熔盐法制备了CaTiO3∶Pr3＋红色荧光粉,应用XRD、SEM、荧光分光光度计等测试手段研究了熔盐法制备对粉体结构、形貌和发光性能的影响。结果表明,以CaCl2为熔盐800℃时保温4h,已完全转变为CaTiO3相,与固相法相比,CaTiO3相的完全转变温度降低了400℃,荧光粉的发光强度提高了1.5倍。     

(Y,Gd)BO_3∶Eu荧光粉的溶胶-凝胶法合成及其发光性能

用溶胶-凝胶法合成等离子显示器(PDP)用红色荧光粉(Y,Gd)BO3∶Eu,研究其在真空紫外光激发下的发光特性.研究结果表明,用溶胶-凝胶法在800 ℃下即能合成类球形形貌,粒度小,结晶性能好的(Y,Gd)BO3∶Eu荧光粉,合成温度比传统高温固相法低400 ℃.该方法合成的(Y,Gd)BO3∶Eu荧光粉在147 nm激发下,发光强度比固相法提高10%,且在626 nm处(Eu3+离子的电偶极跃迁5D0→7F2)的纯红色发射峰强度显著提高,因此用溶胶-凝胶法制备 (Y,Gd)BO3∶Eu可以有效的提高荧光粉的发光效率和色纯度.     

BaNb2O6:Eu3+,Bi3+荧光粉的制备及发光性质研究

采用传统的固相法制备了BaNb2O6:Eu3+荧光粉,对其晶体结构、形貌和发光性质进行了X-射线衍射(XRD)、扫描电镜(SEM)和荧光光谱(PL)表征.结果表明,经1 200°C烧结后可得到BaNb2O6纯相;BaNb2O6:Eu3+荧光粉的颗粒大小分布较均匀,粒径大约为1～3μm;Ba1-xNb2O)6:Eu3+x...     

Gd_2Mo_4O_(15):Eu~(3+)荧光材料的制备与发光性能研究

采用了高温固相法制备了稀土离子Eu3+掺杂的Gd2M04O15:Eu3+荧光粉,通过X-射线衍射(XRD)和荧光光谱的测定,分别讨论了烧结温度、烧结时间以及稀土离子Eu3+掺杂量对发光性能的影响.测试结果表明Gd2Mo4O15:Eu3+荧光粉在近紫外区(uv)(393 nm)和蓝光区(464 nm)可以被有效的激发,Gd2Mo4O15:Eu3+荧光粉发出明亮的红光,对应于Eu3+的4f-4f跃迁,当Eu3+的掺杂浓度约为40 mol%时,在616nm处的发光强度最大.在393,464 nm的吸收分别与目前应用的紫外光和蓝光LED芯片相匹配.因此,Gd2Mo4015:Eu3+是一种可能应用在白光LED上的红色荧光材料.     

NaY（WO4）2:Eu3+红色荧光粉的水热法制备及其发光性能研究

采用水热法,在乙二醇:水=1:4的环境下制备出了NaY(WO4)2:Eu3+红色荧光粉,研究了体系pH值对粉体结构、形貌以及发光性能的影响.采用X-射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、荧光分光光度计(PL)对样品进行了表征.结果表明:在180℃下可以得到纯相结构的NaY(WO4)2:Eu3+荧光粉,反应体系的pH值对合成的粉体的形貌及发光性能有显著影响.     

红色荧光材料Ba_3Eu(BO_3)_3:Ce~(3+)的制备及性能研究

用高温固相法制备了Ce3+掺杂的红色荧光材料——Ba3Eu(BO3)3∶Ce3+.用X-射线衍射仪、扫描电子显微镜、荧光分光光度计对所得样品的物相、表面形貌、激发光谱和发射光谱进行表征.结果表明,用程序升温法合成,稀土离子Ce3+的最佳掺杂量w=10%、最佳焙烧温度T=750℃.在最佳工艺条件下制备出的荧光材料的发光性能较好.     

燃烧法合成自激发荧光粉X3(VO4)2(X=Sr,Ba)

为了寻求廉价荧光粉,采用燃烧法于850 ℃合成了自激发蓝绿色荧光粉X3(VO4)2(X=Sr,Ba),研究了燃烧温度对荧光粉发光强度的影响,并用XRD、TEM和荧光/磷光分光光度计对该荧光粉的物相、形貌及发光性能进行了表征和研究.结果表明:在340 nm激发下可得到一个400～600 nm宽发射峰.     

微片结构Gd3GaO6：Eu3＋荧光粉的合成及其发光特性

以柠檬酸为燃烧剂,乙二醇为分散剂采用燃烧固相法制备Gd3GaO6：Eu3＋新型荧光粉．利用X线粉末衍射、扫描电镜和荧光光谱分别对热处理后产物的结构、形貌和发光性能进行表征．结果表明：700℃燃烧10min并在1200℃热处理5h即可获得产物Gd3GaO6：Eu3＋,其空间点群为P21（4）,形貌为微米片结构;产物的特征发射峰来自于Eu3＋的5D0→7FJ（J=1,2,3,4）跃迁,其中在616nm处发射最强,为Eu3＋的。5D0→7F2的特征红色发射;宽激发带主要来自于O2-→Eu3＋的荷移跃迁吸收．该产物是一种性能优良的红色荧光粉．     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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