Raman analysis of epitaxial graphene on 6H-SiC (000(1)) substrates under low pressure environment

This article investigates the formation mechanism of epitaxial graphene on 6H-SiC (000(1)) substrates under low pressure of 2 mbar environment.It is shown that the growth temperature dramatically affects the formation and quality of epitaxial graphene.The higher growing temperature is of great benefit to the quality of epitaxial graphene and also can reduce the impact of the substrate for graphene.By analyzing Raman data,we conclude that epitaxial graphene grown at 1600 ℃ has a turbostratic graphite structure.The test from scanning electron microscopy (SEM) indicates that the epitaxial graphene has a size of 10μm.This research will provide a feasible route for fabricating larger size ofepitaxial graphene on SiC substrate.     

云计算的开放架构设计

云计算作为IT基础设施的提供者,必须提供开放接口才能够获得广泛使用,否则只是专用系统而不能称为云计算。文章从云计算各个层面,包括基础设施即服务(IaaS)、平台即服务(PaaS)、软件即服务(SaaS)讨论了服务开放的实现方式,并提出了如何处理开放引发的安全及升级问题的解决方案。最后指出利用开放的云计算服务可以给传统的电信服务发展带来新的契机。     

COREX用煤及检测块煤热解新方法

COREX工艺是目前惟一工业化的熔融还原炼铁新工艺,其优势之一为可以尽可能少用焦炭,能直接使用块煤。针对COREX工艺给出了其用煤要求,为了减少其焦炭使用量,发挥其直接用煤优势,必须找出焦炭与块煤使用的匹配关系,对块煤运输和装卸产生的粉煤总结出几种利用途径。通过观测用于COREX-3000的块煤在熔化气化炉中的裂解和脱气过程,提出了块煤热爆裂性能和脱气性能测试的实验室可视化试验方法。     

Optical and photocatalytic properties of arginine-stabilized cadmium sulfide quantum dots

Currently, environmental pollution caused by organic compounds leads to severe negative consequences in the human society. Therefore, the removal of these pollutants from aqueous media has become one of the most important issues in environmental science. In the present study, CdS QDs were successfully prepared under aqueous conditions using l-arginine as the stabilizing agent. Optical property determination results reveal that the CdS QDs exhibited strong absorption and photoluminescence in a visible wavelength region. Moreover, the CdS QDs could effectively degrade two organic dyes under visible light irradiation. This suggested that the CdS QDs prepared in this work might be used as the potential photocatalyst to effectively treat the organic pollutants under visible light irradiation.     

MoS2/有序介孔碳复合材料的制备及性能研究

采用水热法合成了纯MoS2及MoS2/有序介孔碳复合材料(MoS2/OMC)。X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)及循环伏安曲线(CV)等分别用来表征样品的结构、形貌及电化学性能。实验结果表明,以钼酸钠和硫脲分别为钼、硫源合成的MoS2/OMC复合材料的性能较纯MoS2有明显提升。MoS2/OMC复合材料的首次放电容量达到1247mAh/g,第二、三次的放电容量分别为948mAh/g、894mAh/g,容量保持率为94%。二、三次充、放电曲线的近乎重合及高倍率下的高放电容量,亦表明该复合电极有极佳的循环稳定性及良好的可逆性。     

PBT/PVA复合纳米纤维膜的制备及性能研究

通过将聚乙烯醇(PVA)与聚对苯二甲丁二醇酯(PBT)不同比例混合进行静电纺丝,对所得PBT/PVA复合纳米纤维膜通过扫描电子显微镜(SEM)、单轴拉伸测试以及水接触角测试进行了表征。结果显示:PBT/PVA混合溶液的可纺性和所得纤维膜形貌随PVA含量增加而变化;纯PBT纳米纤维膜表现为较低的力学性能和疏水性(水接触角为135°),而少量PVA的混入(PBT/PVA=20/1或10/1)可以有效提高所得纤维膜力学性能和亲水性,尤其10/1的PBT/PVA复合纤维膜在力学性能提高的同时表现为超亲水特性(水接触为0°)。     

薄壁铜铝管电阻焊焊接界面的微观结构研究

利用SEM、EDS等技术对电阻焊薄壁铜铝管焊接界面进行研究,并结合Cu-Al二元相图进行界面分析。研究结果表明在铜铝连接管的焊接界面处,铜与铝进行原子的互扩散,且铜原子向铝侧扩散的深度比铝原子向铜侧扩散的深度要大。对界面进行背散射电子分析和能谱分析,发现界面存在柱状晶形貌的CuAl2相和呈灰白相间的层片状的α-Al与CuAl2的共晶。讨论柱状晶与共晶组织的形成与性能,并分析其对接头性能的影响。     

感应重熔Fe-Al金属间化合物涂层的制备及性能研究

采用Fe粉和Al粉的混合粉料,利用火焰喷涂加感应重熔制备出Fe-Al金属间化合物涂层,并在750℃退火2h。用扫描电子显微镜(SEM)观察涂层的微观形貌,用X射线衍射仪(XRD)测定涂层的物相组成。并用维氏硬度计测得退火前后涂层显微硬度,发现涂层显微硬度退火前后变化很大,特别是手工混料涂层,退火后涂层显微硬度增幅高达150%。     

Friction stir lap welding of AA2024-T4 with drastically different thickness

The International Journal of Advanced Manufacturing Technology - Friction stir lap welding is a promising technology to obtain high-strength joints of Al alloys in aviation and aerospace...     

Efficient Catalytic Conversion of Polysulfides by Biomimetic Design of “Branch‑Leaf” Electrode for High‑Energy Sodium–Sulfur Batteries

Rechargeable room temperature sodium–sulfur(RT Na–S)batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates.Herein,a 3D“branch-leaf”biomimetic design proposed for high performance Na–S batteries,where the leaves constructed from Co nanoparticles on carbon nanofibers(CNF)are fully to expose the active sites of Co.The CNF network acts as conductive“branches”to ensure adequate electron and electrolyte supply for the Co leaves.As an effective electrocatalytic battery system,the 3D“branch-leaf”conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction.DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co–S–Na molecular layer on the Co surface,which can enable a fast reduction reaction of the polysulfides.Therefore,the prepared“branch-leaf”CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g^−1 at 0.1 C and superior rate performance.