GaN基二维八重准晶光子晶体制备与应用

针对半导体发光管（LED）器件普遍存在的出光效率低下的问题,首次采用聚焦离子束技术成功地在GaN基发光器件上制备了GaN二维八重准晶光子晶体（2D-8PQCs）结构。并将二维八重准晶光子晶体应用于电注入器件,当刻蚀孔径为600nm,空气填充因子为30％时,得到了表面出光效率高达2.5倍的增强。通过微区电致发光与发光图样的研究,证实二维八重准晶光子晶体结构抑制了导波模式的传播,将LED中导波模式耦合到辐射模式,从而起到改进表面出光的作用。上述结果为二维准晶光子晶体在GaN基发光器件中的应用提供了一种可能的途径。     

微接触压印法制备ZnO纳米线二维光子晶体

采用基于微接触压印的一种新工艺制备了ZnO纳米线二维光子晶体,工艺包括两个步骤:第一,利用Zn(AOc)_2溶胶作为墨水和PDMS作为印章,通过微接触压印技术在ITO衬底上制备图形化的ZnO种子层;第二,采用80℃的低温水热法在图形化的ZnO种子层上选择性的生长ZnO纳米线,获得ZnO纳米线二维光子晶体。测试结果表明:通过优化后的工艺,实现了微结构完整的图形化ZnO种子层;通过短时间的水浴生长实现ZnO纳米线二维光子晶体。由于光子晶体的多重散射效应,透过ZnO纳米线光子晶体的光波呈周期性震动的光谱曲线与带状色散条纹。     

基于聚苯乙烯模板的二维光子晶体的制备

给出了一种制备聚苯乙烯小球蛋白石结构光子晶体,并运用单层聚苯乙烯小球为模板制备了一系列二维光子晶体的方法,包括α-Fe_2O_3二维碗状光子晶体和ZnO柱二维光子晶体结构,并通过大面积反射谱测量了聚苯乙烯胶体光子晶体的光子带隙.聚苯乙烯小球模板法制备方法简单,成本低,重复性好,而且是大面积生长,为制备各种形貌的二维光子晶体提出了新思路.     

荧光染料掺杂的高效率、高亮度黄色OLEDs

利用真空蒸镀的方法制备了结构为:ITO/m-MTDATA(20 nm)/NPB(15 nm)/DPAVBi:Rub(x nm,2%)/Alq3(25 nm)/Li F(0.5 nm)/Al(100 nm)的器件.研究了掺杂层的不同厚度(x=15,25和30 nm)对器件性能的影响.结果是当掺杂层的厚度为25 nm时,器件的性能最好.当电流密度为524.22 m A/cm2时,获得最大电流效率,为4.37 cd/A;获得最大亮度,为22 890 cd/m2.器件的高亮度与高效率主要是因为主客体之间的能量转移很充分.     

光阱中多个金纳米棒的双光子荧光效应及热熔合过程

本文利用单束、波长对应金纳米棒长轴表面等离子共振的飞秒脉冲激光对多个长度为40 nm,直径为10 nm的金纳米棒颗粒进行了光捕获,系统研究了金纳米棒颗粒在共振激光作用下的双光子荧光及光致热熔合效应.实验结果表明,在光阱捕获过程中金纳米棒颗粒会激发出明显的双光子荧光.当多个金纳米棒被光力捕获在光斑中心时,金纳米棒发生热熔化并熔合成大尺寸的金纳米团簇.利用这种单光束光镊熔合技术,我们在玻璃衬底上制备了二维有序的金纳米团簇阵列.这一研究对利用金纳米棒颗粒来制备微纳光子结构及多功能光子器件等具有重要的指导意义.     

Ag层厚度对Ag/Fe/Ag薄膜的微结构和磁特性的影响

室温下,利用直流对靶磁控溅射设备制备了Ag(x)/Fe(35nm)/Ag(x)系列薄膜,x=1,2,3,4nm.利用扫描探针显微镜(SPM)观测了样品的表面形貌及磁畴结构,应用X射线衍射仪(XRD)分析了样品的晶体结构,通过振动样品磁强计(VSM)测量了样品的磁特性.研究表明,非磁性Ag层厚度对Ag/Fe/Ag系列薄膜的微结构和磁特性有很大的影响.SPM观测显示,随Ag层厚度增加磁畴尺寸呈现先减小后增加的趋势.VSM结果显示,矫顽力的变化与磁畴尺寸的变化趋势是一致的,x=3nm时,垂直膜面矫顽力达到最大.     

荧光染料掺杂的高效率、高亮度白色OLEDs

利用真空蒸镀的方法,制备了结构为:ITO/m-MTDATA(20 nm)/NPB(10 nm)/Rubrene(0.2 nm)/DPVBi:BCzVBi(x nm,10%)/Alq_3(20 nm)/Cs_2CO_3:Ag_2O(2 nm,20%)/Al(100 nm)的器件.研究了掺杂层的不同厚度(x=20,25和30)对器件性能的影响.结果是当掺杂层的厚度为25 nm时,器件的性能最好.电流密度为285.064 m A/cm~2时,器件B获得最大亮度为13 560 cd/m~2,同时获得最大电流效率,为4.76 cd/A.器件的高亮度与高效率主要是因为主客体之间的能量转移很充分.     

高Al组分AlGaN基紫外LED结构材料

采用金属有机物气相外延(MOVPE)技术在c面蓝宝石衬底上,引入脉冲原子层外延技术,制备了一系列表面平整度较高的高Al组分AlGaN基异质结构外延片.并采用电子束金属蒸镀技术及优化热退火方法,获得了良好的欧姆接触电极,进一步将外延片制备成LED管芯.通过对量子结构有源层量子阱混晶组分的设计和调整,掌握并实现了主波长260～330 nm紫外LED结构材料的制备.     

磷钨氧化物薄膜的制备及其有机发光二极管

有机发光二极管(OLED)中的高性能材料和新制备工艺一直是该领域的研究热点.以磷钨杂多酸溶液为前驱体,采用旋涂法在氧化铟锡(ITO)阳极上经退火制备磷钨氧化物薄膜,通过不同的退火条件调控薄膜的功函数.以X射线光电子能谱(XPS)、原子力显微镜(AFM)和紫外可见吸收光谱(UV-Vis)表征其组成、表面粗糙度和透光性.以此薄膜作为空穴注入层(HIL),构建结构为[ITO/HIL(35,nm)/NPB(25,nm)/C545T:Alq3(40,nm)/Alq3(15,nm)/LiF(1,nm)/Al(100,nm)]的绿光OLED器件.结果表明,采用旋涂法制备了表面平整、透光度大于92%,及功函数可调的磷钨氧化物薄膜,基于真空中退火的磷钨氧化物空穴注入层的器件表现出优异的发光性能,启亮电压为3.6,V,最大亮度为31,160,cd/m2,最大电流效率为11.54,cd/A,最大功率效率为4.45,lm/W.这一结果为研究金属氧化物空穴注入材料及其成膜方法以及获得高性能发光器件提供了新的启示.     

硅衬底高光效GaN基蓝色发光二极管

经过近十年的探索,作者在国际上率先突破了硅衬底高光效Ga N基蓝光LED材料生长技术及其薄膜型芯片制造技术,制备了内量子效率和取光效率均高达80%的单面出光垂直结构Ga N基蓝光LED,并实现了产业化和商品化,成功地应用于路灯、球炮灯、矿灯、筒灯、手电和显示显像等领域.本文就相关关键技术进行全面系统地介绍.发明了选区生长、无掩模微侧向外延等技术,仅用100 nm厚的单一高温Al N作缓冲层,制备了无裂纹、厚度大于3μm的器件级Ga N基LED薄膜材料,位错密度为5×108 cm-2.发明了自成体系的适合硅衬底Ga N基薄膜型LED芯片制造的工艺技术,包括高反射率低接触电阻p型欧姆接触电极、高稳定性低接触电阻n型欧姆接触电极、表面粗化、互补电极、Ga N薄膜应力释放等技术,获得了高光效、高可靠性的硅基LED,蓝光LED(450 nm)在350 m A(35 A/cm2)下,光输出功率达657 m W,外量子效率为68.1%.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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