新型Ca_9Sr(PO_4)_6Cl_2:Mn~(2+)红色荧光粉的合成及其发光特性

采用高温固相法合成一系列不同摩尔分数Mn~(2+)掺杂的Ca_9Sr(PO_4)_6Cl_2荧光粉,并利用X射线粉末衍射及荧光光谱手段对所制备样品的结构及其发光特性进行表征,在波长为412nm蓝光激发下,Ca_9Sr(PO_4)_6Cl_2:Mn~(2+)荧光粉产生中心波长位于643nm的红光宽带发射,其色坐标为(0.68,0.32)。研究发现,Mn~(2+)掺杂摩尔分数为15%时获得的Ca_9Sr(PO_4)_6Cl_2:Mn~(2+)荧光粉表现出最佳发光特性。利用Van Uitert理论模型分析发光强度与掺杂浓度之间的关系,表明Ca_9Sr(PO_4)_6Cl_2:Mn~(2+)荧光粉中Mn~(2+)浓度猝灭的机制为电偶极-电偶极相互作用。新型Ca_9Sr(PO_4)_6Cl_2:Mn~(2+)荧光粉可望发展成一种具有良好应用前景的白光LED用红色荧光粉材料。     

红色荧光粉Mg_2TiO_4∶Mn~(4+)的制备及发光性能

采用高温固相反应成功地制备出Mn~(4+)激活的Mg_2TiO_4∶Mn~(4+)红色荧光粉,并对它的结构及发光性能进行了测试表征.实验结果表明:合成的样品能被270~570 nm的紫外光和蓝光有效地激发,产生很强的红光发射.样品的主发射峰位于660 nm左右,这对应于Mn~(4+)的2E2→4A2跃迁.通过Mn~(4+)掺杂浓度的调控,优化了Mg_2TiO_4∶Mn~(4+)的发光性能.最后将优化后的Mg_2TiO_4∶0.002 5Mn~(4+)荧光粉和YAG涂覆于~465 nm发射的Ga N芯片上,制作成暖白光发光二极管(LED).该LED器件表现出很强的暖白光发射.     

共沉淀法合成Mn~(2+)-SnO_2纳米粒子及其磁性能研究

以SnCl_4.5H_2O作为锡源,采用共沉淀法制备SnO_2纳米粒子,对产物进行了TGA,XRD,TEM,EDX表征,以检测产物的微观结构和形貌,证实Mn掺杂物被掺入到SnO_2主晶格中而不改变金红石结构,而且所制备的SnO_2纳米粒子结晶性好,尺寸较小。对Mn~(2+)离子掺杂的SnO_2纳米粒子进行了磁性能测试,结果表明,Mn~(2+)离子的加入不改变SnO_2纳米粒子的铁磁性,只改变顺磁性。随着温度的降低,Mn~(2+)离子掺杂的SnO_2纳米粒子磁化强度逐渐增强。同一温度下,随着磁场的增强,Mn~(2+)离子掺杂的SnO_2纳米粒子磁化强度逐渐增强。     

铈锰铽激活硼酸镁的光致发光

研究不同组成铈锰铽激活硼酸镁的发射光谱和激发光谱表明:只含Mn~(2+)的硼酸镁发光很弱;Ce~(3+)能很好地吸收254nm紫外光并能把能量传递给Mn~(2+),Ce~(3+)→Mn~(2+)能量传递效率最高可达99.8％,从而获得发明亮红光的荧光粉。Ce~(3+)→Mn~(2+)能量传递的机理为共振传递。铈锰铽共激活的硼酸镁中,Tb~(3+)和Mn~(2+)都有较高的发光效率,增加Tb~(3+)浓度使色坐标x值降低,y值升高;相反,增加Mn~(2+)浓度使色坐标x值升高、y值降低,改变Tb~(3+)、Mn~(2+)的浓度可调整荧光粉发光的颜色。     

掺杂晶体MgO:Mn~(2+)的零场分裂与静水压的关系

本文利用赵敏光的过渡金属离子Mn~(2+)的d轨道,研究了掺杂晶体MgO:Mn~(2+)的晶场吸收谱。在光谱计算的基础上我们研究了零场劈裂α因子和合理地解释了MgO:Mn~(2+)的α因子对静水压力的依赖关系。     

黑曲霉HD-404酸性蛋白酶若干动力学性质的研究

研究金属离子、EDTA、表面活性剂、碘乙醚等对黑曲霉HD-404酸性蛋白酶活力的影响的结果表明:Cu~(2+)、Mn~(2+)对酶有明显的激活作用;Cu~(2+)、Mn~(2+)和Al~(3+)同时使用时,产生协同效应,显著提高酶活力;十二烷基磺酸钠(SDS)、西湖高效洗洁剂对酶有明显的抑制作用;在以酪蛋白为底物时,AgNO_3是酶的不可逆抑制剂。     

固氮鱼腥藻HB686固氮_放氢与谷氨酰胺合成酶的关系

固氮鱼腥藻HB686(Anabaena azotica HB686)的固氮和放氢被氨抑制与蛋氨酸砜亚胺(MSX)解除氨抑制的作用呈平行关系.谷氨酰胺能抑制固氮和放氢,而对谷氨酰胺合成酶(GS)和吸氢酶却有激活作用.固氮血腥藻在Mg~(2+)介质中的乙炔还原活性和放氢量皆比在Mn~(2+)介质中的高,而GS的活性则相反.不同波长的光照射对固氮、放氢和GS活性有不同的影响.     

锌,锰,卟啉（TPPS）络合物的伏安法和吸收光谱法研究

本文报道在氨性溶液中(pH=8.8)TPPS和Zn~(2+)-TPPS,Mn~(2+)-TPPS络合物的形成及伏安行为;在Cd~(2+)和咪唑存在时,室温下可以较快形成相应的络合物,用伏安法和光度法研究了它们的催化作用;比较了Zn~(2+)-TPPS和Mn~(2+)-TPPS的氧化还原性质以及氧的影响。     

CaSO_4:RE(Eu,Dy,Tm),Mn磷光体的热释光发光谱

选择稀土Eu、Dy、Tm和过渡金属元素Mn,在CaSO_4中进行掺杂,制成了CaSO_4:RE、CaSO_4:Mn和CaSO_4:RE,Mn多晶粉末,测量了三种物质的热释光发光谱,研究稀土离子和Mn杂质在CaSO_4发光中的相互作用。实验发现:稀土离子与Mn离子既是发光中心,又能对陷阱能级的分布产生影响;Mn~(2+)对稀土离子150℃以上的高温热释光峰没有增强作用,只对较低温度的发光峰有显著的增强作用,即存在Mn~(2+)向稀土离子的能量转移。但Mn~(2+)对CaSO_4中不同价态的稀土离子的增强作用差异很大,对Eu~(2+)的发光有很强的增强作用,对Dy~(3+)、Tm~(3+)只有较弱的增强。     

11—钨钴合镓酸及其过渡金属盐的合成与性质研究

本文研究了用离子交换法首次制得固体11—钨钴合镓酸。用复分解法制备了未见文献报道的ZH_5[Ga(H_2O)CoW_(11)O_(39)]·xH_2O(Z=Zn~(2+)、Ni~(2+)、Mn~(2+))。研究了它们的红外、紫外、x—射线粉末衍射和差热性质。     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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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