Spin Transport in a Rashba Ring-Quantum Dot System Pumped by Microwave Fields

We report a theoretical study on producing electrically spin-polarized current in the Rashba ring with parallel double dots embedded, which are subject to two time-dependent microwave fields. By means of the Keldysh Green's function method, we present an analytic result of the pumped current at adiabatic limit and demonstrate that the interplay between the quantum pumping effectand spin-dependent quantum interference can lead to an arbitrarily controllable spin-polarized current in the device. The magnitude and direction of the charge and spin current can be effectively modulated by system parameters such as the pumping phase difference, Rashba precession phase, and the dynamic phase difference of electron traveling in two arms of ring; moreover, thespin-polarization degree of the charge current can also be tuned in the range [-∞, +∞]. Our findings may shed light on the all-electric way to produce the controllable spin-polarized charge current in the field of spintronics.     

过模慢波结构频率反射特性及谐振腔的影响

利用有限元方法求解:S-参数矩阵,研究了过模慢波结构对圆波导TM01,TM02模的反射特性,分析了在慢波结构末端加入谐振腔后,由于两端口的不对称性而造成的对反射特性影响。结果表明,在TM01的π模频率附近,慢波结构和谐振腔组成的系统对无谐振腔一侧端口入射TM01模的反射增大,而对有谐振腔一侧端口入射TM01模的反射减小。根据计算结果,解释了普通多波切伦柯夫振荡器所用慢波结构周期数较多的原因,说明了在多波切伦柯夫振荡器中引入谐振腔后,不但可以减少所用慢波结构周期数,而且有利于提高微波输出效率。     

马克思的制度经济思想再认识

在当代经济学的语境下,本文从一种广义的制度分析新视角,首次重新解读了马克思（以及恩格斯）著作中的制度经济论述。通过深入细致的思想梳理、观点辨析、理论提炼与重构工作发现,马克思的经济学是经济思想史上第一个重要的制度经济学分析体系。这一分析体系既包含有关社会经济制度问题的基本概念与原理的“一般性分析”,也包括关于资本主义市场经济制度的历史特性的“专门性分析”。两个分析层次之间具有内在的逻辑联系,反映了从“一般”到“特殊”的创新性理论演绎思路。对马克思的制度经济学分析体系的重新发掘与提炼表明,马克思的制度经济思想不仅在制度经济思想史上占具至关重要的地位,而且对于丰富和推进当代制度经济理论发展也具有重要的学术启示与借鉴意义。     

Effect of long-period stacking ordered phase on thermal stability of refined grains in Mg-RE-based alloys

The refined grains in both as-cast Mg-10Y-1Zn-2Zr (WZ101?K, wt.%) and Mg-10Y-1Al (WA101, wt.%) alloys have been found to have superior thermal stability after solution treatment. Plate-shaped, but different polytypes of long-period stacking ordered (LPSO) phases distributed along grain boundaries are considered as the predominant inhibitors of grain growth. Based on the plate-shaped features of the LPSO phases, a modified Zener’s model is established and the predicted limiting grain sizes are in a good agreement with the experimental results. Therefore, this model has strong potential for designing advanced Mg-RE-based alloys with high strength and high creep resistance at high temperatures.     

Poly(amidoamine)s: Past,present, and perspectives

Poly(amidoamine)s (PAAs) are a family of synthetic polymers obtained by stepwise polyaddition of prim‐ or sec‐amines to bisacrylamides. Nearly all conceivable bisacrylamides and prim‐ or sec‐amines can be employed as monomers endowing PAAs of a structural versatility nearly unique among stepwise polyaddition polymers. PAAs are degradable in aqueous media, including physiological fluids. Many of them are remarkably biocompatible notwithstanding their cationic character. PAAs are per se highly functional polymers and, in addition, can be further functionalized giving rise to an endless variety of polymeric structures meeting the requisites for applications in such apparently disparate fields as inorganic water pollutants scavengers, sensors, drug and protein intracellular carriers, transfection promoters, peptidomimetic antiviral and antimalarial agents. In this review, the unique chemistry of PAAs is discussed and a vast library of PAA structures and PAA applications from the beginning to the present days reported. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2319–2353     

Röntgenographische Strukturuntersuchung geschmolzener Magnesium-Blei Legierungen

Abstract

Um Aufschluß über die Atomanordnung in geschmolzenen Magnesium-Blei Legierungen zu erhalten, wurden rontgenographische Strukturuntersuchungen durchgeführt.     

Solvatochromic Solvent Polarity Measurements In Analytical Chemistry: Synthesiss And Applications Of Et-30

Abstract

The E_T(30) scale of solvent polarity has been shown to be useful in examining many diverse analytical processes. It is based on the charge transfer absorption of 2,6-diphenyl-4-(2,4,6-triphenyl-N-pyridinio)phenolate (referred to as ET-30 in this paper). Unfortunately, use of the E_T(30) scale has been hindered by (a) the lack of a commercial source of the ET-30 dye and (b) the lack of an English language synthetic procedure. Here we discuss recent applications of the E_T(30) scale to analytical techniques, as well as a simplified procedure for the synthesis of ET-30.     

Separation and Analysis of o.p'-DDD and its Lipophilic Metabolite,O.P'-DDE,in Tissue,Faeces and Plasma

Abstract

An analytical procedure based on electron capture gas chromatography for the determination of o,p′-DDD, a drug used for the treatment of Cushing′s syndrome, is presented. Detection of a metabolite, identified as o,p′-DDE, is also described.     

Photoconductivity of erbium-doped germanium

We have applied the technique of Photo Thermal Ionization Spectroscopy (PTIS) to the study of an erbium-doped p-Ge epitaxial layer, grown by MBE on an undoped n-type germanium substrate. The Er-doped Ge layer shows continuum photoconductivity response in the far-infrared region extending from 70 cm^–1 to 900 cm^–1. This type of epitaxial Er-doped Ge layers is a potentially attractive system for photoconductivity detectors of far-infrared radiation. Below 900 cm^–1 three acceptor-like charged states can be distinguished with ionization energies of 9, 26.6 and 50 meV. Additionally, a study of the photoconductive response of the same sample for radiation from 1000 cm^–1 to 10000 cm^–1, i.e., for radiation energies well inside the forbidden gap to energies above it, shows a wealth of levels, some of which have previously been associated with erbium.On leave from: Instituto de Física, Universidad Autónoma de Puebla, Puebla, México