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。     

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。     

多碱光电阴极单色光电流测试技术研究

多碱光电阴极的单色光电流实质上反映的是其在该单色光照射下的量子产额。该文阐述了单色光电流的测试原理和影响量子产额的因素,介绍了多碱光电阴极多信息量测试系统,该系统可在多碱光电阴极制备过程中在线测试、处理阴极的单色光电流,测得的曲线有助于分析和指导工艺,从中还可得到光电子逸出深度的信息。该文给出并分析了在该系统应用于玻璃阴极实验管制备过程中的测试结果。     

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．     

S20光电阴极光谱响应特性的理论研究

该文根据光电阴极的量子产额谱，导出了光谱响应Ｓ（λ），通过选择合适参数，计算的Ｓ２０光谱响应曲线与实验基本吻合。该文也分析了阴极厚度Ｄ，阴极结构参量Ｐ，光电阴极光谱响应截止波长λ＿ｊ和光电子逸出深度Ｌ对Ｓ（λ）的影响，认为Ｄ、Ｐ和λ＿ｊ是决定Ｓ２０阴极性能的主要因素。     

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。     

半透明多碱阴极浅氧敏化研究

根据多碱阴极理想模型:Na_3KSb+K_2CsSb+sb·Cs 偶极层,提出用 Cs_2O 取代 K_2CsSb+Sb·Cs 偶极层,很可能形成 p—n Na_2KSb—Cs_2O异质结光电阴极。用研制的氧发生器,以常规的碱金属源在超高真空系统中制备了 Na_2KSb,然后采用 NEA 光电阴极的激活工艺,用铯、氧交替激活 Na_2KSb,获得 p—n Na_2KSb—Cs_2O 光电阴极。结果表明,这种光电阴极在紫外—红外范围内具有较高的量子产额,其长波截止超过1.06um,达到1.1μm。     

CsI/Ni/LiF光电发射特性研究

本文用 H_2水冷毛细管真空紫外辐射源对 CsI/Ni/LiF 半透明真空紫外光阴极进行了测试研究,得出该光阴极的伏安特性曲线,光阴极厚度与光电发射关系;测出真空紫外辐射源的工作特性.通过测试与计算得出 CsI/Ni/LiF 半透明光阴极的量子产额,利用对照测试法指出该阴极具有良好的“日盲”效应.     

渐变层线性掺杂的InGaAs/InP场助阴极的能带结构设计与仿真

为了进一步提高阴极材料的量子效率,设计了一种新的InGaAs/InP转移电子(Transferred Eletron,TE)光电阴极结构,且在不同掺杂浓度、渐变层宽度、外加电压等条件下,利用Matlab仿真工具对能带曲线进行了模拟。实验结果表明:发射层与吸收层的掺杂比例应不高于50;能带曲线得到了更为严格的优化参数范围,可以使表面发射几率进一步提高;且由于计算中考虑掺杂浓度、费米能级移动对能带结构变化的影响,并对描述渐变区能带的双曲函数进行改进,使得计算结果比以往的计算更为准确。结果表明此种结构可以极大地提高阴极的量子效率,对进一步改进阴极参数和制备出更高灵敏度的TE阴极具有实际的指导意义。     

用蒸发法制备NEA光电阴极初探

用蒸发法制备负电子亲和势(NEA)光电阴极,探讨了两个可能性:(一)改进现有多碱阴极的工艺规范,制备负电子亲和势光电阴极。(二)用蒸发法制备Ⅲ—Ⅴ族负电子亲和势光电阴极。     

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~~