铁电半导体耦合光伏器件的历史与最新进展

本文介绍了新型铁电-半导体耦合光伏器件的发展历史和现状, 阐述了所观察到的非经典行为, 即开路电压在直流偏置电场控制下的迟滞的现象. 将之与含有光诱导偶极子场的有机光伏器件和量子点电池、压电光电子器件、铁电光伏器件、钙钛矿电池等进行比较, 发现偶极子极化电场在多种光伏器件中均存在, 甚至可能起到主导作用. 因此, 提出了偶极子场半导体器件的概念, 期望从更广义的范围涵盖结场型器件和非结场型偶极子器件, 为促进光伏发电领域更多的创新提供思路.     

Measurement of the Seperation between Atoms beyond Diffraction Limit

We propose a scheme to obtain the distance of two identical atoms placed inside the standing wave field by monitoring the collective resonance fluorescence spectrum emitted by the two particles. We find three different parameter ranges, depending on the distance of the atoms as compared to the transition wavelength. For large interparticle distances, dipole-dipole coupling is negligible, and the main system evolution arises from the interaction with the standing wave field. In the small-distance limit, the dynamics is dominated by the dipole-dipole interaction. Finally, in the intermediate region, a rich interplay of the various couplings arises, which however is lifted for strong driving laser fields. The present measurement procedure allows us to distinguish the three cases. In each of the cases, we show how to determine the distance of the two particles and their respective positions relative to the nodes of the standing wave field with fractional-wavelength precision.     

带电粒子在偶极子电场中的运动

求得了带电粒子在电偶极子产生的电场中的径向运动方程，分析了带电粒子在该电场中各种可能的运动规律。     

偶极子在非均匀外场中的受力

电偶极子ｐ在非均匀电场Ｅ（Ｒ）中受到的力在一般情况下不是Ｆｅ＝　（ｐ·Ｅ）而是Ｆｅ＝ｐ·Ｅ，磁偶极子ｍ在非均匀磁场Ｂ（Ｒ）中受到的力一般也不是Ｆｍ＝　（ｍ·Ｂ）而是Ｆｍ＝　Ｂ·ｍ本文推导出普遍的表达式，并讨论了原公式可以应用的特殊条件．     

Elastic Interaction between a String of Cells and an Individual Cell

The elastic interaction between a string of cells and an individual cell on an elastic substrate is investigated numerically using the force-dipole model. This interaction is found to be of short range, and the cut-off distance is about 1.4 times of the length of the cell. The energy-minimization distance is about half the cellular length. The specific relationship between the cellular reorientation and the cellular position are obtained quantitatively. A critical distance is found, and the cellular orientation has an abrupt change at this transition point.     

带电粒子在偶极子电场中的运动

求得了带电粒子在电偶极子产生的电场中的径向运动方程 ,分析了带电粒子在该电场中各种可能的运动规律     

在磁场中运动诱导的偶极子量子相位

在磁场中运动诱导的偶极子量子相位尉海清韩汝珊（北京大学物理系，北京１００８７１）１９９５年９月，美国《物理评论通讯》（Ｐｈｙｓ．Ｒｅｖ．Ｌｅｔ）第７５卷第２０７１页上发表了由北京大学物理系韩汝珊教授指导他的学生尉海清完成的一篇介观物理量子相位方面的...     

固体介质中电偶极子介电常数温度特性与能级密度分布关系

从电介质极化的基本方程出发,实现了直接从介电常数温度特性关系获得偶极子任意能级密度分布,该理论并不需要已知偶极子任何性质,均能实现分布计算. 关键词：     

半导体异质结(111)面的界面偶极子及其对能带偏移的影响

本文采用紧束缚的界面键极性模型(interface-bond-polarity-model),计算了匹配的半导体异质结(111)面的界面偶极子,并将计算结果与(110)和(001)面的结果进行了比较,讨论了界面取向和界面成分对偶极子的影响。结果表明,对于两边同是Ⅲ-V族半导体或同是Ⅱ-Ⅵ族半导体的异质结,界面偶极子几乎不依赖于界面的取向和界面的组成,因此,能带偏移也基本上是各向同性的。对于两边由不同类型半导体组成的异质结,如Ⅱ-Ⅵ/Ⅲ-Ⅴ体系、Ⅲ-Ⅴ/Ⅳ和Ⅱ-Ⅵ/Ⅳ体系,混和的阴离子(111)界面给出的偶极子小于零,而混和的阳离子(111)界面给出的偶极子大于零,二者的平均值等于中性的(110)界面的偶极子。 关键词：     

Role of Electromagnetic Dipole Operator in the Electroweak Penguin Dominated Vector Meson Decays of B Meson

The pure annihilation type decays Dd^0→Фγand Bs→ργ receive only colour suppressed penguin contributions with a very small branching ratio in the standard model. When we include the previously neglected electromagnetic dipole operator, the branching ratios can be enhanced to R（^-Bd^0→Фγ）≈ 1×10^-11 and R（^-Bs→ργ）～（6 - 16） ×10^-10, which are one order magnitude larger than previous study using the QCD factorization approach. The new effect can also give a large contribution, of order 10^-9, to transverse polarization of B→Фρ and B →ωФ, which is comparable to the longitudinal part. These effects can be detected in the LHCb experiment and the super-B factories.     

电偶极子与单摆

电偶极子是电磁学基本模型之一,其电场强度分布颇有特点.通常教材要么给出电势然后做梯度计算,要么通过矢量叠加直接给出场强,推导比较数学化,学生难以对偶极子场强特点和物理图像获得直观理解.本文把熟知的力学单摆和偶极子联系起来,通过力电类比给出偶极子电场的两种形式,特别是不依赖坐标的场强形式,清楚阐明了各分量特点,还给出类比...     

Ce, Y-TZP陶瓷的内耗峰和介电损耗峰机制

测量了淬火前后8Ce，0．5Y-TZP陶瓷（稳定剂Y2O3的摩尔分数为0．50％）在室温到250℃温度范围内的内耗行为，并对出现的内耗峰机理进行了研究，发现淬火前后的样品在100℃左右均出现的内耗峰与YZr，VOE偶极子的再取向有关，而淬火后样品出现的高温内耗峰起源于马氏体相变。此外，本文还研究了8Ce，0．5Y-TZP和8Ce，0．75Y-TZP陶瓷在室温到400℃温度范围内的介电损耗，计算了介电驰豫的激活能，结果表明与内耗试验中机械驰豫的激活能一致。     

平板波导光子阱中自发发射特性

本文从腔量子电动力学角度讨论了平板波导光子阱中自发辐射特性与阱厚度之间的依赖关系,从而对光学微腔的设计提供了理论依据.     

Ce, Y-TZP陶瓷的内耗峰和介电损耗峰机制

测量了淬火前后8Ce, 0.5Y-TZP陶瓷(稳定剂Y2O3的摩尔分数为0.50%)在室温到250℃温度范围内的内耗行为,并对出现的内耗峰机理进行了研究,发现淬火前后的样品在100℃左右均出现的内耗峰与YZr‘V偶极子的再取向有关,而淬火后样品出现的高温内耗峰起源于马氏体相变.此外,本文还研究了8Ce, 0.5Y-TZP和8Ce, 0.75Y-TZP陶瓷在室温到400℃温度范围内的介电损耗,计算了介电驰豫的激活能,结果表明与内耗试验中机械驰豫的激活能一致.     

多极子阵列声波成像测井技术研究*

多极子阵列声波成像测井已经成为测井中主要方法之一,在地层评价与油气田开发中有重要作用。在已有理论与数值模拟的基础上,经过近十年的技术攻关,我们已经在多极阵列声波成像仪器制造、测试与数值处理等主要关键技术方面都取得了长足的进展,具体包括高温正交偶极子发射换能、高温低频单极子换能器、声系测试、多极子阵列声波测井高温电路及仪器集成、资料处理及解释等主要方面。所研制的仪器及资料处理方法,经过与国外同类仪器的测井结果进行了对比分析,验证了所研发的仪器的可靠性和处理方法的正确性,这些关键技术为我国声学测井仪器装备技术研发和快速发展打下了基础,提供了技术支撑。     

Active Control of Cellular Orientation through In-Situ Stress in the Substrate

We investigate the orientation of cells on substrates to find possible methods for controlling the cellular orientation. The force dipole model is employed in our modelling and simulation. The elastic interaction between cells as well as the elastic interaction between the cell and in-situ stress field in the substrate are found to be the two main physical mechanisms to control the cellular orientation. The former interaction dominates the cellular orientation when the in-situ stress is small, while the later dominates when the in-situ stress is large enough. Two cells tend to align perpendicularly on a free substrate, but the cellular orientation varies with the increasing in-situ stress. Two cells tendto align in parallel when the normal stress is large enough. Their direction is perpendicular to the extension stress direction or parallel to the compression stress direction. When the positive in-situ shear stress is large enough, the two cells tend to align at -45°. Based on this theoretical simulation, it is believed that the cellular orientation on substrates can be controlled by thein-situ stresses.     

Discrete Dipole Approximation Aided Design Method for Nanostructure Arrays

A discrete dipole approximation （DDA） aided design method is proposed to determine the parameters of nanostructure arrays. The relationship between the thickness, period and extinction efficiency of nanostructure arrays for the given shape can be calculated using the DDA. Based on the calculated curves, the main parameters of the nanostructure arrays such as thickness and period can be determined. Using this aided method, a rhombic sliver nanostructure array is designed with the determinant parameters of thickness （40 nm） and period （440 nm）. We further fabricate the rhombic sliver nanostructure arrays and testify the character of the extinction spectra. The obtained extinction spectra is within the visible range and the full width at half maximum is 99nm, as is expected.     

Dispersion Energy in a Molecule Composed of Two Anisotropic Vibrating Dipoles

For the first time, we derive the dispersion energy for a molecule which involves the anisotropic dipole interaction by virtue of the invariant eigen-operator method, which greatly simplifies the usual calculation if one uses the Schroedinger equation.