Near-Infrared Lasing in Four-Zigzag Edged Nanographenes by 1D versus 2D Electronic π-Conjugation

The search of compounds emitting in the near-infrared (NIR) has been accelerated owing to their use in biomedical and telecommunications applications. In this regard, nanographenes (NGs) are attractive materials adequate for integration with other technologies, which have recently demonstrated amplified spontaneous emission (ASE) and lasing across the visible spectrum. Here, the optical and ASE properties of four-zigzag edged NGs of the [m,n]peri-acenoacene family are reported, whose size is increased through conjugation extension by varying n (from 3 to 5) while keeping m = 2. Results show that such 1D conjugation extension method is more efficient in terms of shifting the photoluminescence (PL) to the infrared (PL at 710 nm in the larger compound, PP-Ar) than through 2D conjugation extension as in previously reported NGs (PL at 676 nm with the largest compound FZ3, with n = 3 and m = 4). Additionally, PP-Ar shows dual-ASE (at 726 and 787 nm), whose origin is elucidated through Raman and transient absorption spectroscopies. These compounds’ potential for red and NIR lasing is demonstrated through the fabrication of distributed feedback lasers with top-layer resonators. This study paves the way towards the development of stable low-cost all-plastic NIR lasers.     

浅析融媒体业务平台网络安全系统的组建

介绍了沂源县融媒体中心网络安全系统的组建、承载业务、主要网络设备及安全设备的性能。     

一段转化炉钢结构架的抗震分析

本文根据静力等效原则探讨了结构物的质量分布和振型的关系以及振型对地震荷载的影响,修正了多质点地震荷载的近似算法,并以一段转化炉刚架抗震分析的结果说明了修正后的近似算法和振型算法所确定的地震荷载是一致的。     

喷射沉积快速凝固技术制备镁合金的研究现状及展望

喷射沉积是一种新型的快速凝固技术,被广泛用于研究和开发高性能的快速凝固材料.叙述了喷射沉积快速凝固技术的原理,综述了喷射沉积镁合金的特点和研究现状,并对其发展前景进行了展望.     

综合物探方法在检测桥墩及墩基础中的应用

详细介绍了在检测深圳罗湖铁路桥桥墩材质和墩基础检测中使用的几种工程物探方法，总结了这些方法的应用经验和体会，说明了在一些工程检测中使用综合物探方法可以取得较好的应用效果。     

原位铝基复合材料的制备及微观组织

提出制备原位合金化和原位反应颗粒共同强化金属基复合材料的概念,并据此制备了原位10％Cu(质量分数,下同）和5．35％α-Al2O3颗粒增强纯铝复合材料（A）以及原位10％Cu,4%Si和15.06%α-Al2O3颗粒共同增强纯铝复合材料（B）。对原位反应过程进行了热力学分析。SEM观察和EDS分析显示,A和B中的原位反应分别生成了合金元素Cu、Cu Si以及Al2O3;原位Al2O3颗粒直径小于0.5μm,在材料中均匀分布。TEM观测显示Al2O3颗粒边角圆滑,与基体结合良好。探讨了原位反应的机理以及在铸造凝固过程中原位颗粒的行为。     

基坑抗隆起稳定安全系数实用计算分析与应用

 总结基坑由于插入深度不足导致的坑底隆起破坏的两种形式，研究基坑抗隆起稳定安全系数Ks计算公式的适用性及局限性，指出常用公式的错误，给出考虑因素更多、更适用的修正公式，并对修正公式的敏感性进行分析。运用该修正公式及数值方法分析基坑变形与Ks值的关系，指出Ks值对控制基坑变形的意义；通过分析发现基坑变形在Ks小于某值时发生突变，证明基坑设计存在一个最优的插入比。给出考虑因素全面、计算简便、更能反映工程实际的Ks计算公式，并得到一些对工程具有指导意义的结论，可以在基坑设计、施工中应用。     

机械合金化制备Ti-Al-Si纳米金属间化合物

4种成分的Ti-Al-Si颗粒T3,T4,T5和T6通过球磨获得非晶.这些非晶在退火时的结构变化分为3个阶段:(1)球磨非晶的部分晶化并产生Ti₅Si₃;(2)其余非晶的完全晶化并依赖于颗粒中Ti和Al的组成产生钛铝金属间化合物,(3)粉末中各相的晶粒长大.晶化反应依粉末成分产生Ti₃Al,TiAl和Al₃Ti.Ti₅Si₃是晶化反应的唯一硅化物.低于800℃退火可获得纳米晶。     

Effect of Precipitating Phases on Tensile Strength and Microstructural Stability of a Spray-Deposited Al-Si-Fe-Mn-Cu-Mg Alloy

Spray deposition is a novel process which is used to manufacture rapidly solidified bulk and near-net-shape preforms. In this study, AI-20Si-5Fe-3Mn-3Cu-1Mg alloy was synthesized by spray deposition technique. The aging process of the alloy was investigated by differential scanning calorimetry (DSC) analysis and transmission electron microscopy (TEM). The results show that two kinds of phases, i.e. S(Al2CuMg) and σ(Al5Cu6Mg2), precipitate from matrix and improve the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300℃). In addition, the σ-Al5Cu6Mg2 is a relatively stable phase which improves microstructural stability of the alloy.