利用扫描开尔文探针显微镜观察薄膜光电器件能级排布

薄膜光电器件的能级结构直接决定了载流子的产生、分离、传输、复合和收集等微观动力学过程,从而决定了器件性能。因此准确获取器件能级结构,是深入理解器件工作机制、推动器件技术革新的重要科学依据。此专论系统地介绍了本课题组利用扫描开尔文探针显微镜(SKPM)表征薄膜光电器件如有机太阳能电池、有机-无机钙钛矿光探测器等器件中界面能级结构的工作。垂直型薄膜器件中的活性材料层被顶电极与底电极封闭,通常难以直接在器件工况下测量其中的界面能级排布,我们发展了横截面SKPM技术来解决这一难题。研究表明,界面层是调控器件能级结构、决定器件极性、提高器件性能的重要手段。本文介绍的表征技术有望在各种薄膜光电器件,诸如光伏器件、光探测器、发光二极管,尤其是各种叠层构型器件的研究中展现出广阔的应用前景。     

Dynamics of hybrid shafts

In this paper the dynamic performance and cross-section deformation of shafts made of metals (steel and aluminum), composites (CFRP and GFRP) and hybrids of metals and composites have been studied. A layered finite degenerated shell element with transverse shear deformation and dynamic behavior is employed. Results obtained show that improvements in dynamic performance and reduction of cross-section deformation of hybrid shafts over metallic and composite shafts are possible.     

将SVRT模型应用到单原子多原子反应F+CH2 D2→CH2 D/CHD2 +DF/HF中

The semirigid vibrating rotor target（SVRT）model is applied for the reaction F+CH2D2→CH2D/CHD2+DF/HF. The time-dependent wave packet approach is also used in the calculation. Reaction probabilities,crosssections,and rate constants are calculated for the title reaction from the ground state of the reagent on the modified J1（MJ1）potential energy surface（PES）for both channels. Numerical calculation shows the oscillatory structures in the energy dependence of the calculated reaction probability. Those structures are generally associated with broad dynamical resonances. They are smooth in the energy dependence of integral cross-sections due to summation over partial waves. The calculated rate constants are in good agreement with the experimental measurement.     

Analytical modeling of constricted channel flow

Analytical flow models are frequently applied when describing constricted channel flow at low and moderate Reynolds numbers. A common assumption underlying such flow models is two-dimensional or axi-symmetrical flow. In this work, two analytical model approaches are formulated in order to overcome this assumption in the case of naturally occurring channel flows for which the assumption might be critiqued. Advantages and flaws of both model approaches are discussed and their outcome is compared with experimental data.     

将SVRT模型应用到单原子多原子反应F+CH2D2→CH2D/CHD2+DF/HF中

由于含时波包方法具有经典的直观又不乏量子力学的准确 ,选择含时波包方法来处理F +CH2 D2 →CH2 D/CHD2 +DF/HF反应 .把半刚性振转子 (SVRT)模型应用到该反应体系中 ,研究了两个通道中该反应从基态反应物开始在修正过的J1(MJ1)势能面上计算出来了反应几率、积分截面、速率常数 .反应几率随能量变化的图的数值结果给出了振荡结构 ,这些振荡结构是可以和动力学振荡联系起来的 .而这些振荡结构在积分截面随着能量变化的图中就被反应几率求和后的平均结果所掩盖了 .速率常数和实验结果的比较也得到了较好的结果 .     

Computation of triple differential cross-sections with the inclusion of exchange effects in atomic K-shell ionization by relativistic electrons for symmetric geometry

The triple differential cross-section for K-shell ionization of silver and copper atoms by relativistic electrons have been computed in the coplanar symmetric geometry with the inclusion of exchange effects following the multiple scattering theory of Das and Seal [1] multiplied by suitable spinors. Present computed results are marginally improved in some cases from the previous computed results [2]. Present results are compared with measured values [3] and with previous computation results [2]. Some other theoretical computational results are also presented here for comparison.      

A rapid-scan device for the determination of spectral line profiles in pulsed discharges

The results of a time-of-flight experiment are presented, in which the total cross-sections for 2–400 eV positrons on H₂, D₂, N₂, and CO were measured. Paper F7 presented at 3rd Internat'l. Conf. Positron Annihilation. Otaniemi, Finland (August 1973).     

Calculation of triple differential cross-sections ofK-shell ionization of medium-heavy atoms by electrons for symmetric geometry

Triple differential cross-section forK-shell ionization of medium-heavy atoms by relativistic electrons has been calculated for coplanar symmetric geometry. In this calculation the final state is described by a non-relativistic wave function of Das and Seal [Phys. Rev. A47 (1993) 2978] multiplied with suitable spinors. Results of the present calculation are compared with the available experimental data and with other theoretical calculations.     

An experimental study on cross-section ratio of coherent to incoherent scattering for 145 keV incident gamma photons

The coherent (Rayleigh) to incoherent (Compton) scattering cross-section ratio of elements, in the range 6 ≤ Z ≤ 82, are determined experimentally for 145 keV incident gamma photons. An HPGe (High purity germanium) semiconductor detector is employed, at scattering angle of 50°, 70° and 90°, to record the spectra originating from interactions of incident gamma photons with the target under investigation. The intensity ratio of Rayleigh to Compton scattered peaks observed in the recorded spectra, and corrected for photo-peak efficiency of gamma detector and absorption of photons in the target and air, along with the other required parameters provides the differential cross-section ratio. The measured values of cross-section ratio are found to agree with theoretical predictions (corresponding to 4.939, 6.704 and 8.264 Å⁻¹ photon momentum transfer) based upon non-relativistic form factor, relativistic form factor, modified form factor and S-matrix theory.