锑化物光电阴极的量子效率

研究了晶粒间界对光电发射的影响，仔细考虑了在单位能量间隔内参与光跃迁的有效电子态密度和光电子逸出几率，提出锑化物阴极的光电发射模型，并导出了量子产额的表达式．借助电子计算机，计算了各种锑化物阴极的量子产额，理论和实验符合较好．     

多碱光电阴极光电信息测试结果与分析

该文根据多碱光是阴极光学信息和光电流监控原理，给出了理论模型，研制了测试仪器，例举了测量结果，并对此作了简单分析，理论的多碱光电阴极光学反射率Ｒ（ｄ）和实测的Ｒ（ｄ）比较可以控制阴极成分，并给出阴极厚度的信息、多碱光电阴极的单色光电流Ｉ（ｄ）、光电子逸出深度以及大量的工艺信息，借此可以调整工艺，改善光电阴极的光谱响应。     

透射式负电子亲和势光电阴极基片的无损检测

本文对用作透射式负电子亲和势光电阴极的Ⅲ—V族半导体基片的无损检测进行了研究。建立了一套带微机处理的高信噪比的激光荧光测试系统,测试了基片的发射层GaAs的掺杂浓度、过渡层Gal_(-x)Al_xAs的组分X值及沿表面X值的均匀性、高X值的测量等。实验结果表明,激光荧光检测为Ⅲ—V族半导体材料的研究提供了一种快速的非破坏性的检测方法,对研究透射式负电子亲和势光电阴极具有重要意义。     

负电子亲和势GaN光电阴极特性研究

分析了NEAGaN光电阴极的产生背景,介绍了NEAGaN光电阴极的结构以及工作模式,研究了GaN光电阴极的光电发射机理以及NEA特性的形成原因,P型GaN经过Cs、O处理后的有效电子亲和势约为一1．2eV。分析表明：充分激活后形成的双偶极层是表面真空能级降低的原因,体内产生的光电子按照光电发射的“三步模型”逸出到真空中。     

用XPS对激活过程中的GaAs光电阴极的表面分析

对ＧａＡｓ光电阴极激活过程中各阶段做了Ｘ射线光电子谱（ＸＰＳ）表面分析，根据ＸＰＳ分析所得数据，改进了激活工艺，提出了获得更好发射性能的光电阴极的最佳Ｃｓ和Ｏ２量，并提出了Ｃｓ和Ｏ２在ＧａＡｓ表面排列的模型．     

多晶半导体三碱光电阴极厚度研究

该文利用多晶半导体三碱光电阴极量子产额公式,研究了光电阴极厚度D与光吸收系数α_T(hv)和光电子逸出深度L的关系,指出阴极厚度与光电阴极光谱响应峰值位置有关。对第一类阴极,厚度应为30nm左右。对第二类阴极则为90nm。预计可通过光电阴极光谱响应峰值位置设计光电阴极厚度。研究结果首次定量给出:随着光电子逸出深度和入射光子波长的增加,光电阴极厚度将增加。如果L在40～55nm之间,则对1.0μm敏感的阴极厚度应在120nm左右。     

AlGaAs基光电阴极光学性质计算模型分析

为了分析不同波长响应对光电阴极结构的要求,提出适用于各类响应的AlGaAs基光电阴极的计算模型.通过宽光谱响应GaAs和窄带响应AlGaAs基光电阴极样品试验证实模型的有效性.基于该模型仿真研究AlGaAs基光电阴极组件中GaAs发射层及各子层、AlGaAs窗口层、Si₃N₄增透层的厚度与400～900 nm单波长光子吸收情况的分布关系.仿真结果表明,同一波长响应下,GaAs发射层对光电阴极吸收率的影响最大,其次是Si₃N₄增透层,而AlGaAs窗口层对吸收率的影响不明显.要得到90%以上的吸收率,在600 nm波长响应下GaAs发射层厚度应大于0.5μm, 700 nm波长响应下GaAs发射层厚度应大于0.8μm, 800 nm波长响应下GaAs发射层厚度应大于1.5μm.400～600 nm波段的光子主要在GaAs发射层表面0.2μm内被吸收,700～800 nm波段的光子主要在GaAs发射层表面0.6μm内被吸收,而850 nm以后的光子在各子层间的吸收比较均匀.该结论对不同响应AlGaAs基...     

New S-25光电阴极红外延伸原因研究

该本研究了S-25与New S-25光电阴极的红外光谱响应特性,分析了New S-25光电阴极红外延伸的原因。研究结果表明:在850～1000 nm范围内New S-25光电阴极红外光谱响应明显提高,主要归因于阴极层较厚,具有较大的阴极结构参量和截止波长。这既是New S-25光电阴极的创新之处,也代表了碱锑光电发射材料的发展方向。     

反射式GaAs负电子亲和势光电阴极的激活

本文叙述反射式ＧａＡｓ负电子亲和势（ＮＥＡ）光电阴极的激活工艺已制备出积分灵敏度为４４０～１１７７μＡ／ｌｍ的光电阴极。文中讨论了对ＮＥＡ光电阴极稳定性的影响因素，铯和氧的作用，以及ＮＥＡ的形成机理。     

多晶半导体三碱光电阴极厚度的理论研究

该文利用辐射强度指数衰减率,多晶半导体三碱光电阴极量子产额公式和光吸收系数公式,首次研究了多晶半导体三碱光电阴极的最佳厚度。结果表明:当I_a/I_0>0.4时,阴极最佳厚度D应在1000A以上,并且D随I_a/I_o上升而增加。高能光子产生的光电子出现在阴极内表面层。该文同时指出:对第一类阴极(S-20,S-20R,S-25),D应为300A左右;对第二类阴极(New S-25,Varo,LEP)则为900A。并预计可通过光电阴极光谱响应峰值位置设计光电阴极厚度。研究结果首次定量给出,随着光电子逸出深度和入射光波长增加,光电阴极厚度增加。如果光电子逸出深度在40～55nm之间,则对1.0μm敏感的阴极最佳厚度D应在1200A左右。     

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