Electrical performance of the embedded-type surface electrodes containing carbon and silver nanowires as fillers and one-step organosoluble polyimide as a matrix

Embedded-type surface electrodes with silver nanowire (AgNW) and carbon nanotube (CNT) as conductive fillers and organosoluble polyimide (PI) as a matrix were investigated for their electrical conductivity and electrical durability under cyclic bending. The chosen polyimide was constituted with 4,4′-oxydiphthalic dianhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane through a one-step process. Two types of surface electrodes of CNT/PI and AgNW/PI were prepared at 90 °C. The flexible CNT/PI and AgNW/PI surface electrodes not only had high electrical conductivities of 6.3 and 100 S/cm, respectively, after 30 spraying cycles but also kept electrical durability after 1200-time bending tests. The ITO-coated ITO/PI and ITO/AgNW/PI electrodes, for a comparative purpose, had severe electrical failure under cyclic bending.     

High-efficiency host free deep-blue organic light-emitting diode with double carrier regulating layers

A bright high-efficiency host-free deep-blue organic light-emitting diode (OLED) is demonstrated. Without the aid of any carrier regulating layer, the deep-blue OLED shows a power efficiency of 1.7 lm W⁻¹ with CIE coordinates of (0.143, 0.098) at 1000 cd m⁻². The respective power efficiency is increased from 1.7 to 2.1 and 2.2 lm W⁻¹ as a single- and double-carrier regulating layers were incorporated. The respective peak luminance also increases from 5250 to 7620 and 9130 cd m⁻², an increment of 45% and 74%. The marked brightness improvement may be attributed to the incorporated carrier regulating layers that effectively lead carriers to recombine in a wider zone. Moreover, the blue emission can be hypsochromic shifted by varying the incorporation position of the carrier regulating layer and the emissive layer thickness.     

Pyrolyzed Cobalt Corrole as a Potential Non‐Precious Catalyst for Fuel Cells

Non‐precious metal catalysts of the oxygen reduction reaction are highly favored for use in polymer electrolyte fuel cells (PEFC) because of their relatively low cost. Here, a new carbon‐black‐supported pyrolyzed Co‐corrole (py‐Co‐corrole/C) catalyst of the oxygen reduction reaction (ORR) in a PEFC cathode is demonstrated to have high catalytic performance. The py‐Co‐corrole/C at 700 °C exhibits optimized ORR activity and participates in a direct four‐electron reduction pathway for the reduction of O₂ to H₂O. The H₂‐O₂ PEFC test of py‐Co‐corrole/C in the cathode reveals a maximum power density of 275 mW cm^?2, which yields a higher performance and a lower Co loading than previous studies of Co‐based catalysts for PEFCs. The enhancement of the ORR activity of py‐Co‐corrole/C is attributable to the four‐coordinated Co‐corrole structure and the oxidation state of the central cobalt.     

Alcohol‐Responsive,Hydrogen‐Bonded,Cholesteric Liquid‐Crystal Networks

Hydrogen‐bridged, cholesteric liquid‐crystal (CLC) polymer networks are adopted as an optical sensor material to distinguish between ethanol and methanol. Fast uptake of the alcohols is facilitated by an incorporated porosity created by breaking the hydrogen bridges and by a previously removed non‐reactive liquid‐crystal agent. The discrimination between the alcohols is based on the diversity in molecular affinity of ethanol and methanol with the hydrogen‐bridged CLC polymer networks. The CLC networks are molecular‐helix‐based, one‐dimensional bandgap materials with a discrete reflection band in the visible part of the spectrum that depends on the pitch of the molecular helix. The changes in positions of the reflection bands of the CLC network accurately discriminate between the alcohol types and provide information on their ratio in case they are blended.     

陶瓷窑炉节能技术工程应用与经济性分析

通过对陶瓷窑炉进行清洁燃料技术改造、燃烧系统技术改造、余热资源回收利用,研究其工程应用的节能效果及经济性。工业应用试验结果表明,窑炉燃水煤气改燃天然气后,平均节能率及减排率为25.6%;窑炉应用预混式二次燃烧技术后,平均节能率及减排率为9.0%;窑炉余热资源回收利用后,平均节能率及减排率为58%;陶瓷窑炉余热资源回收利用、清洁燃料技术应用,产生的节能和减排效果十分明显。     

环氧液晶对木质素/聚丙烯复合材料结构和性能影响

以4,4'-二(β-羟乙氧基)联苯(BP2)、环氧氯丙烷及对苯二甲酰氯等为原料,通过取代反应合成一种小分子的环氧液晶(LCEP),将该LCEP与木质素(lignin)/聚丙烯(PP)进行共混改性,采用FT-IR、DSC、POM及TGA等对LCEP结构和液晶相转变行为进行了表征,并研究了LCEP含量对Lignin/PP复合材料物理力学性能和热性能的影响。利用SEM观察了复合材料断裂形貌,探讨其增韧增强机理。结果表明:加入4%的LCEP聚丙烯/木质素复合材料的综合性能最好,其冲击强度、弯曲强度和弯曲模量较未改性前分别提高了38.6%、30.5%和20%,热稳定性、结晶性和结晶速率也有明显提高。     

MPI下三维FDTD并行运算的分析与实现

基于Message-Passing Interface(MPI)的编程环境,以PML(Perfectly Matched Layer)为吸收边界条件,讨论了时域有限差分法FDTD的三维并行运算情况。通过一定的数值计算,定量地给出了MPI下FDTD并行算法中的网格数、进程数、分割方式三者之间的关系以及对计算效率的影响。     

Security-State Adjustable Gateway with Threat-Based Configuration

This paper proposes a configurable secure gateway architecture which allows the system administrators to dynamically configure the security mechanisms upon deployment or during the run-time. Rather than allowing the system administrators to turn on or off individual security mechanisms, the proposed architecture allows the administrators to configure the gateway based on the security threats to be overcome. The current common architecture leads to tremendous administration overhead and increases the chance of misconfiguration vulnerability. We propose a novel software architecture to aid the product designers to avoid the misconfiguration vulnerability and the end-users to ease the administration overhead. The software architecture makes use of the threats to the gateways and the occurrence relation between the threats to configure the security software components on the gateways. With the software architecture, the end-users can focus on determining the desired security features rather than the software configuration. Moreover, the architecture allows the product designers or security service to incrementally revise the software configuration when new threats appear.     

青岛体育中心体育馆楼盖振动特性分析与对比

对青岛体育中心体育馆比赛场地——楼盖部分建立了有限元分析建模,对比了三种软件求解出的楼盖振型信息,并讨论了楼盖边界条件对结构振型产生的影响。结果表明,建模软件的选择对自振特性计算结果影响较大,推荐配合现场实测来确定楼盖的真正动力特性;板四周边界条件将影响振动模态。     

Salt effect of lithium bromide on the solution polymerization of acrylonitrile

Abstract

In this paper, the salt effect of lithium bromide (LiBr) on the dimethyl formamid (DMF) solution polymerization of acrylonitrile was studied. From the experimental data, we proposed a possible mechanism and derived its rate expression to determine the kinetic parameters for this system. The results show that the values of k_v/k_tr (1.984～79.365) and k_t/k² _tr (3.311×l0²～3.156×l0⁵ sec·mole/1) of the DMF‐LiBr solution polymerization of acrylonitrile are larger than those of the DMF‐LiCl solution polymerization of acrylonitrile shown by Bamford and others. These results can be explained by the basicity of salt and the dissociation of polyacrylonitrile in the DMF‐LiBr solution.