机械磨抛对CdZnTe薄膜阻变特性的影响

采用磁控溅射法在ITO玻璃上制备了CdZnTe薄膜,探究机械磨抛对CdZnTe薄膜阻变特性的影响。通过对XRD图谱、Raman光谱、AFM显微照片等实验结果分析阐明了机械磨抛影响CdZnTe薄膜阻变特性的物理机制。研究结果表明,磁控溅射制备的薄膜为闪锌矿结构,F43m空间群。机械磨抛提高了CdZnTe薄膜的结晶质量;CdZnTe薄膜粗糙度(Ra)由磨抛前的3.42 nm下降至磨抛后的1.73 nm;磨抛后CdZnTe薄膜透过率和162 cm^-1处的类CdTe声子峰振动峰增强;CdZnTe薄膜的阻变开关比由磨抛前的1.2增加到磨抛后的4.9。机械磨抛提高CdZnTe薄膜质量及阻变特性的原因可能是CdZnTe薄膜在磨抛过程中发生了再结晶。     

Effect of strain on charge density wave order in α-U

The effect of strain on charge density wave (CDW) order in $\alpha$-U is investigated within the framework of relativistic density-functional theory. The energetical stability of $\alpha$-U with CDW distortion is enhanced by the tensile strain along $a$ and $b$ axes, which is similar to the case of negative pressure and normal. However, the tensile strain along $c$ axis suppresses the energetical stability of CDW phase. This abnormal effect could be understood from the emergence of a new one-dimensional atomic chain along $c$ axis in $\alpha$-U. Furthermore, this effect is supported by the calculations of Fermi surface and phonon mode, in which the topological objects and the dynamical instability show opposite behaviors between strains along $a$/$b$ and $c$ axes.     

Conformational change-modulated spin transport at single-molecule level in carbon systems

Controlling the spin transport at the single-molecule level, especially without the use of ferromagnetic contacts, becomes a focus of research in spintronics. Inspired by the progress on atomic-level molecular synthesis, through first-principles calculations, we investigate the spin-dependent electronic transport of graphene nanoflakes with side-bonded functional groups, contacted by atomic carbon chain electrodes. It is found that, by rotating the functional group, the spin polarization of the transmission at the Fermi level could be switched between completely polarized and unpolarized states. Moreover, the transition between spin-up and spin-down polarized states can also be achieved, operating as a dual-spin filter. Further analysis shows that, it is the spin-dependent shift of density of states, caused by the rotation, that triggers the shift of transmission peaks, and then results in the variation of spin polarization. Such a feature is found to be robust to the length of the nanoflake and the electrode material, showing great application potential. Those findings may throw light on the development of spintronic devices.     

The behavior of capillary suspensions at diverse length scales: From single capillary bridges to bulk

Liquid-liquid-solid systems are becoming increasingly common in everyday life with many possible applications. Here, we focus on a special case of such liquid-liquid-solid systems, namely, capillary suspensions. These capillary suspensions originate from particles that form a network based on capillary forces and are typically composed of solids in a bulk liquid with an added secondary liquid. The structure of particle networks based on capillary bridges possesses unique properties compared with networks formed via other attractive interactions where these differences are inherently related to the properties of the capillary bridges, such as bridge breaking and coalescence between adjacent bridges. Thus, to tailor the mechanical properties of capillary suspensions to specific requirements, it is important to understand the influences on different length scales ranging from the dynamics of the bridges with varying external stimuli to the often heterogeneous network structure.     

Supramolecular Arrangement and DFT analysis of Zinc(II) Schiff Bases: An Insight towards the Influence of Compartmental Ligands on Binding Interaction with Protein

We report, for the first time, a detailed crystallographic study of the supramolecular arrangement for a set of zinc(II) Schiff base complexes containing the ligand 2,6-bis((E)-((2-(dimethylamino)ethyl)imino)methyl)-4-R-phenol], where R=methyl/tert-butyl/chloro. The supramolecular study acts as a pre-screening tool for selecting the compartmental ligand R of the Schiff base for effective binding with a targeted protein, bovine serum albumin (BSA). The most stable hexagonal arrangement of the complex [Zn − Me] (R=Me) stabilises the ligand with the highest FMO energy gap (ΔE=4.22 eV) and lowest number of conformations during binding with BSA. In contrast, formation of unstable 3D columnar vertebra for [Zn − Cl] (R=Cl) tend to activate the system with lowest FMO gap (3.75 eV) with highest spontaneity factor in molecular docking. Molecular docking analyses reported in terms of 2D LigPlot+ identified site A, a cleft of domains IB, IIIA and IIIB, as the most probable protein binding site of BSA. Arg144, Glu424, Ser428, Ile455 and Lys114 form the most probable interactions irrespective of the type of compartmental ligands R of the Schiff base whereas Arg185, Glu519, His145, Ile522 act as the differentiating residues with ΔG=−7.3 kcal mol⁻¹.     

黄绿色葡萄石的矿物学特征及谱学研究

葡萄石可以以板状、片状、葡萄状、肾状、放射状或块状集合体的形式产出,因其美丽的外观和特殊的晶体结构,近年来受到了学者的广泛关注。本文通过电子探针、粉晶X射线衍射仪、傅里叶变换红外光谱仪、显微拉曼光谱仪、紫外可见分光光度计等仪器对黄绿色葡萄石的成分、结构及谱学特征进行了分析与探讨。葡萄石的主要致色元素为Fe,且Fe³⁺经常取代Al³⁺占据八面体配位,Fe²⁺经常取代Ca²⁺存在于空隙中。电子探针数据表明:Fe与Al的含量变化整体呈现负相关关系,Fe与Ca的含量变化也整体呈现负相关关系,Fe含量相对较高的样品其黄绿色调加深。XRD图谱和拉曼光谱的结果表明:在葡萄石中绿帘石以包裹体的形式存在。红外光谱和拉曼光谱表明葡萄石中存在硅氧四面体和铝氧八面体两种架构,紫外可见吸收光谱揭示了葡萄石的致色机理。本文对葡萄石的矿物学特征及谱学特征进行系统分析,为后续葡萄石的进一步研究提供思路与实验数据。     

Characterizations of modalities and lex modalities

A reflective subuniverse in homotopy type theory is an internal version of the notion of a localization in topology or in the theory of ∞-categories. Working in homotopy type theory, we give new characterizations of the following conditions on a reflective subuniverse L: (1) the associated subuniverse $L^{\prime }$ of L-separated types is a modality; (2) L is a modality; (3) L is a lex modality; and (4) L is a cotopological modality. In each case, we give several necessary and sufficient conditions. Our characterizations involve various families of maps associated to L, such as the L-étale maps, the L-equivalences, the L-local maps, the L-connected maps, the unit maps ${\eta }_X$, and their left and/or right orthogonal complements. More generally, our main theorem gives an overview of how all of these classes related to each other. We also give examples that show that all of the inclusions we describe between these classes of maps can be strict.     

非线性玻尔兹曼方程的傅里叶谱方法

玻尔兹曼方程作为空气动理学中最基本的方程之一,是连接微观牛顿力学和宏观连续介质力学的重要桥梁.该方程描述了一个由大量粒子组成的复杂系统的非平衡态时间演化:除了基本的输运项,其最重要的特性是粒子间的相互碰撞由一个高维,非局部且非线性的积分算子来描述,从而给玻尔兹曼方程的数值求解带来非常大的挑战.在过去的二十年间,基于傅里叶级数的谱方法成为了数值求解玻尔兹曼方程的一种很受欢迎且有效的确定性算法.这主要归功于谱方法的高精度及它可以被快速傅里叶变换加速的特质.本文将回顾玻尔兹曼方程的傅里叶谱方法,具体包括方法的导出,稳定性和收敛性分析,快速算法,以及在一大类基于碰撞的空气动理学方程中的推广.