掺Er3+碲铌酸盐玻璃的发光特性及其J-O理论计算

以TeO2,Nb2O5,ZnO,Na2O为基质制备了掺铒碲铌酸盐玻璃,应用McCumber原理计算的结果表明:4mol% Nb2O5的加入使碲酸盐玻璃在1.53 μm处的受激发射截面提高了8%,其峰值达8.9×10-21 cm2,而受激发射截面的有效带宽几乎不变.同时应用Judd-Ofelt理论计算了玻璃中Er3+离子的自发跃迁几率、荧光分支比和辐射寿命等参量.     

掺Er3+离子碲酸盐玻璃的光谱性质研究

测量了掺Er3 离子碲酸盐玻璃的吸收光谱和荧光光谱,经荧光光谱测试发现掺Er3 离子碲酸盐玻璃的荧光半高宽可达80 nm,应用McCumber理论计算了1 531 nm处的受激发射截面可达7.5×10-21cm2.对Er3 离子在不同基质玻璃中光谱特性的比较发现,Er3 离子在碲酸盐玻璃中具有相对较高的受激发射截面和宽的荧光半高宽.     

Er3+离子掺杂的碲酸盐玻璃光谱性质分析

用976 nm光激发测量了室温下掺Er3 碲酸盐玻璃的上转换发光,讨论了上转换发光机制.同时测量了掺Er3 离子碲酸盐玻璃的吸收光谱和荧光光谱,发现掺Er3 离子碲酸盐玻璃的荧光半高宽可达80 nm,应用McCumber理论计算了1 531 nm处的受激发射截面可达0.75×10-20cm2.对Er3 离子在不同基质玻璃中光谱特性的比较,发现了Er3 离子在碲酸盐玻璃中具有相对较高的受激发射截面和宽的荧光半高宽.     

掺Yb3+硅酸盐和磷酸盐激光玻璃的光谱性质

采用熔融法制得掺Yb3+硅酸盐玻璃和磷酸盐激光玻璃,并对其物理性能和光谱性能进行研究.研究结果表明掺Yb3+硅酸盐玻璃的受激发射截面和荧光寿命分别为0.67×10-20cm2和1.2 ms;而掺Yb3+磷酸盐玻璃的受激发射截面和荧光寿命分别为0.75×10-20cm2和1.0 ms.掺Yb3+硅酸盐玻璃的受激发射截面和荧光寿命的乘积比掺Yb3+磷酸盐玻璃的略大,表明掺Yb3+硅酸盐玻璃有较好的增益效果;掺Yb3+硅酸盐玻璃比掺Yb3+磷酸盐玻璃的热膨胀系数低,但其非线性折射率却远比掺Yb3+磷酸盐玻璃的高.     

Er3+/Yb3+共掺铅铌磷酸盐玻璃光纤放大器特性

以P2O5、Nb2O5、Na2O、Ga2O3和PbCl2为基质制备Er3 /Yb3 共掺磷酸盐(EYPNGP)玻璃.应用McCumber原理研究的结果显示,EYPNGP玻璃在1530 nm处的峰值受激发射截面和有效带宽分别为6.20×10-21cm2和56.6 nm,大于常规的掺铒磷酸盐玻璃.数值模拟计算结果表明,对于EYPNGP光纤放大器而言,利用较短的激活长度就可获得足够的信号光放大.     

Tm3+在氟氧化物玻璃中的光谱性质

通过测量Tm掺杂氟氧化物玻璃的光吸收谱,根据Judd-Ofelt理论,拟合得到了Tm3+离子的J-O强度参量Ω2=1.955×10-20 cm2,Ω4=2.629×10-20 cm2,Ω6=1.279×10-20 cm2.利用强度参量,给出氟氧化物玻璃中Tm3+离子各激发能级的自发辐射跃迁速率、辐射寿命、荧光分支比和积分发射截面等光谱参量的预计值,发现许多跃迁振子强度大于10-6且积分发射截面大于10-18cm,如(3F,3H)4→3H6(1707nm)跃迁的振子强度、积分发射截面分别为3.593×10-6,3.180×10-18cm,若上能级有足够高的量子效率,可能实现激光发射.而蓝光波段1G4→3H6(466nm)跃迁也有较大的振子强度(1.112×10-6)和积分发射截面值(0.984×10-18cm).     

xZnO-20Nb_2O_5-(80-x)TeO_2系玻璃组成对性能影响

为研究Zn O-Nb2O5-Te O2亚碲酸盐玻璃组成对玻璃性能的影响,采用熔融法制备了不同摩尔百分含量Zn O(0 mol%,2 mol%,4 mol%,6 mol%,8 mol%)的Zn O-Nb2O5-Te O2亚碲酸盐玻璃.利用拉曼光谱仪、红外吸收光谱仪、DTA差热分析仪等手段对玻璃样品进行了表征.研究表明:当Zn O的掺量为4mol%时,亚碲酸盐玻璃的玻璃化温度Tg最低;表观密度和折射率都达到最大值.Te O2、Nb2O5以及OH基在玻璃体中存在形式的不同是Zn O-Nb2O5-Te O2亚碲酸盐玻璃性能变化的主要原因.研究结论为稀有金属掺杂亚碲酸盐玻璃领域的研究提供了可行的研究思路.     

掺钕PLZT电光陶瓷的光辐射特性

研究了掺钕锆钛酸铅(PLZT)电光陶瓷的光学特性,利用Judd-O fe lt(J-O)理论计算该材料的强度参量:Ω2=0.7747×1-0 20cm2,Ω4=0.9856×1-0 20cm2,Ω6=0.9264×1-0 20cm2,并用强度参量计算了4F3/2亚稳态的辐射寿命(394μs)、受激发射截面iσj、荧光分支比,测量了4F3/2亚稳态的荧光寿命(168μs)并计算了该能级的荧光量子效率.同时还研究了该材料在803 nm激发下的上转换荧光特性.分析表明掺钕PLZT电光陶瓷在多功能器件、集成光学等方面有潜在的应用价值.     

掺钕聚合物光纤的光辐射特性

制备了掺钕螯合物的聚合物阶跃型光纤.研究三价钕离子在钕螯合物掺杂的聚甲基丙烯酸甲酯(PMMA)中的吸收光谱和发射光谱.根据Judd-Ofelt理论,用吸收光谱计算钕离子在PMMA中的光学跃迁的强度参量:Ω2=33.967×10-20cm2,Ω4=4.465×10-20cm2,Ω6=3.942×10-20cm2.用该参量计算钕离子激发态(4F3/2)的辐射跃迁几率(2167.4s-1)和辐射寿命(461.4μs),同时计算了受激发射截面σij(4F3/2→4I11/2)和荧光分支比β(4F3/2→4IJ′).分析表明,Nd(DBM)3掺杂的PMMA可望用于聚合物光纤放大器和激光器.     

基于相干控制的超快光开光材料研究

相干控制是近年来国际上的一个研究热点。本文采用了飞秒相干控制技术对新型无序稀土材料掺铒锌铌碲酸盐玻璃（ZnO-Nb2O5-TeO2：Er2O3）上转换荧光相干控制及其作为超快光开关材料关键因素：荧光强度及响应时间进行分析与探索,并对其作为高速光开关材料的可能性与实用性进行了简要的展望。     

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

正~~