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.     

含Nb2O5碲酸盐玻璃的热力学稳定性和光谱性质

在掺铒碲酸盐玻璃中加入Nb2O5以提高其热力学稳定性,测试了4种掺铒碲酸盐玻璃的热力学稳定性参数及其吸收光谱、荧光光谱.应用Judd-Ofelt理论计算了玻璃的强度参数Ω(Ω2=(5.99～10.38)×10-20 cm2,Ω4=(1.91～2.67)×10-20 cm2,Ω6=(0.92～1.28)×10-20 cm2),应用McCumber理论计算了受激发射截面.比较了不同组成对碲酸盐热力学稳定性和光谱性质的影响.实验结果表明,0.70TeO2-0.15ZnO-0.05BaO-0.10Nb2O5玻璃具有较大的受激发射截面(10.96×10-21 cm2)和荧光半高宽(67 nm),热力学稳定性良好,是一种理想的掺Er3+宽带光纤放大器用基质玻璃.     

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.     

Er3+:Y0.5Gd0.5VO4晶体荧光光谱性质

室温下测量了用968 nm LD激发Er3+:Y0.5Gd0.5VO4晶体的上转换发光,并讨论其上转换发光机制.同时测量了Er3+:Y0.5Gd0.5VO4晶体的荧光光谱和吸收光谱,发现Er3+:Y0.5Gd0.5VO4晶体的荧光半高宽可达68 nm,利用McCumber理论计算了1 531 nm处的受激发射截面为3.52 pm2,这表明Er3+:Y0.5Gd0.5VO4晶体是一种优良的潜在上转换激光器增益介质.     

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.     

一种Er3+/Yb3+共掺锗碲铋钾玻璃的光谱性质

用熔融法制备了Er3 /Yb3 共掺TeO2-GeO2-B i2O3-K2O玻璃样品,对玻璃进行了差热分析并测试了玻璃的吸收光谱和上转换光谱.应用Judd-Ofelt理论计算了Er3 /Yb3 共掺锗碲铋钾玻璃的3个强度参数,及Er3 各能级的振子强度、自发辐射跃迁几率、荧光分支比和辐射寿命等光谱参数.通过977 nm的激光二极管抽运,在室温下同时观察到绿色(522和546 nm)和红色(658 nm)的荧光发射,分别是由于Er3 自2H11/2→4I15/24、S3/2→4I15/2和4F9/2→4I15/2跃迁而产生.强烈的绿光和红光发射均来源于双光子吸收过程.     

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.     

不同Er~(3+)离子掺杂浓度下硼铋酸盐玻璃荧光浓度猝灭研究

制备了系列不同Er3+离子掺杂浓度的硼铋酸盐玻璃样品,在常温条件下测量了样品的吸收光谱和荧光衰减曲线。通过分析Er3+离子4I13/2能级的荧光衰减几率,建立了Er3+基于OH-基团作为猝灭中心的浓度猝灭模型。通过电偶极-电偶极相互作用机理计算了Er3+离子在硼铋酸盐玻璃中发生荧光浓度猝灭的相互作用微参量,并与其它玻璃基质进行了比较。     

铋化物发光玻璃中Er3+离子的J-O光谱参量的计算分析

贵金属等离子体对稀土离子发光晶体材料的发光有着一定的增强作用.本文对基质为60 Bi2O3-20SiO2-20Ga2O3的Er3+(0.5％)Ag(0.5％)铋化物发光玻璃进行了吸收光谱的测量.利用J-O理论分析了 Er3+在该基质中的振子强度、自发辐射速率、积分发射截面和荧光分支比等光谱参数.通过振子强度和3个参量Ωλ(λ=2,4,6)的拟合计算,根据拟合结果对Er3+的各能级跃迁的积分发射截面、荧光分支比等光谱参数进行计算分析,发现这些参数有着较大的数值,表明Er3+在本文所研究的基质材料中具有较强的发光能力.     

铒镱共掺碲酸盐玻璃材料上转换光谱性质

用熔融-淬冷法制备了玻璃样品系统75TeO2-2OZnO-(4.6-x)La2O3-0.4Er2O3(x=0,0.4,0.8,2.0,3.2,4.0)),研究了镱离子的掺入对该玻璃系统上转化光谱的影响,结果表明:当Yb3 离子浓度达到2mol%的时候,上转换红光和545nm绿光都达到了最大值,此时绿光强度是未掺Yb3 时的6倍左右,红光强度为未掺Yb3 时的4倍左右.通过Judd-Ofelt理论对该玻璃系统的光谱参量进行了详细计算与分析.随着Yb3 离子溶度的增加,4S3/2能级的荧光寿命和量子效率都呈现先增加后减少的趋势,在溶度迟到2mol%时,荧光寿命和量子效率分剐达到最大值0.26ms和58.9%.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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