面向租户的虚拟机定制化组网技术

基于OpenStack 设计并实现了一个面向租户的虚拟机定制化组网系统,通过资源的元数据定义和基于模板的协同操作,实现云基础设施（计算、存储和网络资源）的自动化部署和管控。具体功能包括统一的图形化租户可拖拽操作、定制化的虚拟机组网编排、动态批量的资源配置更新、网络接口粒度上的服务质量控制以及基于虚拟机网络连接关系的优化映射算法等。该系统可以为租户提供网络配置能力,使租户可以方便、快捷而不受制于技术细节地进行虚拟机组网;性能上降低了网络平均时延,实现了资源的高效匹配,提高了资源利用率。     

铁链镶嵌锯齿形氮化硼纳米带半金属铁磁性的第一性原理研究

基于第一性原理,研究了铁链单侧边界钝化型的锯齿形氮化硼纳米带（简称为Fe-terminated ZBNNRs）和铁链连接型的锯齿形氮化硼纳米带（简称为Fe-jointed ZBNNRs）的电子结构及磁性。Fe-terminated ZBNNRs 对于不同带宽的BN纳米带都是半导体型的,而Fe-jointed ZBNNRs 对于不同带宽的BN纳米带则为半金属型。这两种 结构各自的磁性主要都是来自于所掺杂的铁原子。Fe-jointed ZBNNRs 的半金属性源自Fe原子的3d轨道与N原子的2p轨道间的强耦合作用。通过分子动力学模拟,证实了该 结构在常温下可以稳定存在。Fe-jointed-ZBNNRs 对于两种不同自旋方向电子的选择过滤作用可以被应用于自旋电子学器件的设计。其它各种不同的过渡金属所形成的连接型的锯齿形氮化硼纳米带（简称为M-jointed ZBNNRs）既可以是金属型的、半金属型的,也可以是半导体型的。     

YG20/45#钢激光焊焊缝组织与界面元素扩散研究

在无填充、不开坡口条件下,以5 k W光纤激光作为热源,研究激光扫描速度对YG20硬质合金与45#钢的焊缝组织与元素扩散的影响规律。分析了YG20/45#钢焊缝成形、组织及元素扩散。讨论了激光扫描速度对于热胀系数差异较大的异质材料焊接的焊缝成形的影响规律。研究结果表明,当被焊材料厚度为2 mm时,采用激光功率P=1.93 k W、激光扫描速度v=2.40 m/min,离焦量-8 mm时,可以获得冶金结合良好的YG20/45#钢焊接接头;随着焊接热输入的增加,硬质合金/焊缝侧界面的碳化钨晶粒粗化,裂纹倾向增加。主要分布在焊缝和硬质合金侧热影响区,降低焊接接头的性能。线扫描分析结果表明,硬质合金中的W、Co与钢中Fe发生了互相扩散,使整个接头达到了很好的冶金结合。     

Molecular‐Scale Hybridization of Clay Monolayers and Conducting Polymer for Thin‐Film Supercapacitors

Development of electrode materials with well‐defined architectures is a fruitful and profitable approach for achieving highly‐efficient energy storage systems. A molecular‐scale hybrid system is presented based on the self‐assembly of CoNi‐layered double hydroxide (CoNi‐LDH) monolayers and the conducting polymer (poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate), denoted as PEDOT:PSS) into an alternating‐layer superlattice. Owing to the homogeneous interface and intimate interaction, the resulting CoNi‐LDH/PEDOT:PSS hybrid materials possess a simultaneous enhancement in ion and charge‐carrier transport and exhibit improved capacitive properties with a high specific capacitance (960 F g^–1 at 2 A g^–1) and excellent rate capability (83.7% retention at 30 A g^–1). In addition, an in‐plane supercapacitor device with an interdigital design is fabricated based on a CoNi‐LDH/PEDOT:PSS thin film, delivering a significantly enhanced energy and power output (an energy density of 46.1 Wh kg^–1 at 11.9 kW kg^–1). Its application in miniaturized devices is further demonstrated by successfully driving a photodetector. These characteristics demonstrate that the molecular‐scale assembly of LDH monolayers and the conducting polymer is promising for energy storage and conversion applications in miniaturized electronics.     

Spiro Linkage as an Alternative Strategy for Promising Nonfullerene Acceptors in Organic Solar Cells

This work focuses on developing diketopyrrolopyrrole (DPP)‐based small molecular nonfullerene acceptors for bulk heterojunction (BHJ) organic solar cells. The materials, SF‐DPP s, have an X‐shaped geometry arising from four DPP units attached to a spirobifluorene (SF) center. The spiro‐dimer of DPP‐fluorene‐DPP is highly twisted, which suppresses strong intermolecular aggregation. Branched 2‐ethylhexyl (EH), linear n‐octyl (C8), and n‐dodecyl (C12) alkyl sides are chosen as substituents to functionalize the N,N‐positions of the DPP moiety to tune molecular interactions. SF‐DPPEH , the best candidate in SF‐DPP s family, when blended with poly(3‐hexylthiophene) (P3HT) showed a moderate crystallinity and gives a J_sc of 6.96 mA cm^?2, V_oc of 1.10 V, a fill factor of 47.5%, and a power conversion efficiency of 3.63%. However, SF‐DPPC8 and SF‐DPPC12 exhibit lower crystallinity in their BHJ blends, which is responsible for their reduced J_sc. Coupling DPP units with SF using an acetylene bridge yields SF‐A‐DPP molecules. Such a small modification leads to drastically different morphological features and far inferior device performance. These observations demonstrate a solid structure–property relationship by topology control and material design. This work offers a new molecular design approach to develop efficient small molecule nonfullerene acceptors.     

Humidity‐Triggered Self‐Healing of Microporous Polyelectrolyte Multilayer Coatings for Hydrophobic Drug Delivery

Layer‐by‐layer (LbL) self‐assemblies have inherent potential as dynamic coatings because of the sensitivity of their building blocks to external stimuli. Here, humidity serves as a feasible trigger to activate the self‐healing of a microporous polyethylenimine/poly(acrylic acid) multilayer film. Microporous structures within the polyelectrolyte multilayer (PEM) film are created by acid treatment, followed by freeze‐drying to remove water. The self‐healing of these micropores can be triggered at 100% relative humidity, under which condition the mobility of the polyelectrolytes is activated. Based on this, a facile and versatile method is suggested for directly integrating hydrophobic drugs into PEM films for surface‐mediated drug delivery. The high porosity of microporous film enables the highest loading (≈303.5 μg cm^?2 for a 15‐bilayered film) of triclosan to be a one‐shot process via wicking action and subsequent solvent removal, thus dramatically streamlining the processes and reducing complexities compared to the existing LbL strategies. The self‐healing of a drug‐loaded microporous PEM film significantly reduces the diffusion coefficient of triclosan, which is favorable for the long‐term sustained release of the drug. The dynamic properties of this polymeric coating provide great potential for its use as a delivery platform for hydrophobic drugs in a wide variety of biomedical applications.     

An improved and provable self‐certified digital signature scheme with message recovery

This paper presents a self‐certified digital signature scheme with message recovery that is proven to be secure. So far, many schemes of this kind have been proposed to keep message secret in the transmission. But Zhang et al. has proposed the man‐in‐middle attack to Shao's self‐certified signature scheme, which is based on discrete logarithm. The attacker can make a new signature by using an old one, but the reason of such man‐in‐middle attack was not referred. We present the scheme of Yoon et al., which is also based on discrete logarithm, that cannot resist man‐in‐middle attack either, give the analysis of the attack, and propose a new scheme. The proposed scheme can resist forgery attack in the random oracle model and avoid message leakage, the man‐in‐middle attack, and meanwhile has several security characters. Compared with some self‐certified schemes, our scheme is the best because of the time cost. Copyright © 2013 John Wiley & Sons, Ltd.     

分层分布式微机保护系统

根据国内外变电站综合自动化微机保护的现状,介绍了分层分布式微机保护系统的结构,功能及通信技术,并例举了ＩＳＡ／ＬＳＡ－３００系列分布式微机保护的特点。