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31.
Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion (ECC) technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly. 相似文献
32.
The early stages of corrosion of AISI 314, HK 40, and Alloy 800H have been studied in a strongly carburizing (aC=0.8), weakly oxidizing
atmosphere at 1098 K. Samples with electropolished and cold-worked surfaces were exposed for up to 400 min. at temperature, in a conventional corrosion rig or in a reaction vessel which was installed within an X-ray photoelectron spectrometer. The latter facility allowed the effects of the specimen heating rate and the rat of gas flow to be investigated. Examination of the corrosion products was accomplished with the aid of XPS, SEM, TEM, and conventional metallography. Initially, surface layers comprised of -Cr2O3, (Mn, Cr)3O4, and SiO2 formed, with layer structure, microstructure, and composition being functions of alloy composition and surface condition. Only on the cold-worked surfaces did a well-developed duplex oxide, consisting of an outer, Cr-rich oxide layer and an inner, SiO2 layer, form. In good agreement with the predicted value of 1.9 wt.%, between 1.4 and 2 wt.% Si in the alloy was required to form a complete SiO2 layer. After an incubation period, -Cr2O3 became unstable and transformed to M7C3; the carbides then grew by diffusion of metal from the alloy substrate. The presence of manganese, as (Mn, Cr)3O4, in the surface oxide influenced the mode of carbide growth, whereas the rate of carbide growth was severely suppressed by a continuous SiO2 layer which acted as a diffusion barrier both to metal and to carbon. It is argued that the SiO2 layer is most effective in reducing carburization when it is free from or contains very few structural defects. 相似文献
33.
GAO Haiyong ZHUANG Huizhao XUE Chengshan WANG Shuyun DONG Zhihua HE Jianting 《稀有金属(英文版)》2005,24(3):267-271
ZnO thin films were deposited on Si(111) substrates through a radio frequency (rf) magnetron sputtering system. Then the samples were annealed at different temperatures in air ambience and ammonia ambience respectively. The structure and composition of the ZnO films were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The morphology of the samples was studied by scanning electron microscopy (SEM). Measured results show that ZnO films with hexagonal wurtzite structure were grown on Si(111) substrates when annealed in the two ambiences. The volatilization process of ZnO in the ammonia ambience at high temperature was discussed and the mechanism of the reaction was analyzed. 相似文献
34.
35.
R. Etchart-Salas V. Rat J. F. Coudert P. Fauchais N. Caron K. Wittman S. Alexandre 《Journal of Thermal Spray Technology》2007,16(5-6):857-865
Direct current Suspension Plasma Spraying (SPS) allows depositing finely structured coatings. This article presents an analysis
of the influence of plasma instabilities on the yttria-stabilized suspension drops fragmentation. A particular attention is
paid to the treatment of suspension jet or drops according to the importance of voltage fluctuations (linked to those of the
arc root) and depending on the different spray parameters such as the plasma forming gas mixture composition and mass flow
rate and the suspension momentum. By observing the suspension drops injection with a fast shutter camera and a laser flash
sheet triggered by a defined transient voltage level of the plasma torch, the influence of plasma fluctuations on jet or drops
fragmentation is studied through the deviation and dispersion trajectories of droplets within the plasma jet.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
36.
The effect of hard anodic oxide and plasma electrolytic oxide coatings on the fatigue strength of 7475-T6 aluminium alloy has been investigated. The coated aluminium alloy was tested using constant load uniaxial tensile fatigue machine. Hard anodising led to an appreciable reduction in the fatigue strength of 7475-T6 alloy of about 75% for a 60 μm thick coating. Further, plasma electrolytic oxidation resulted in reduction of the fatigue strength of about 58% for a 65 μm thick oxide coating. The decrease in fatigue strength of the hard anodic oxide coatings was associated with the stress concentration at the microcracks in the coating. The better fatigue performance of the PEO coatings was attributed to the development of the compressive residual internal stress within the coatings. The reduction in the fatigue strength of the PEO coatings as compared to the uncoated material was associated with the development of the tensile residual internal stress within the substrate. This may cause an early crack initiation in the substrate adjacent to the coating. 相似文献
37.
用Java设计的基于三层结构的答疑系统 总被引:1,自引:0,他引:1
介绍了一个用Java进行设计的基于三层结构的答疑系统,用于辅助日常教学工作.系统由客户服务器模式和浏览器服务器模式构成,包括答疑、提问和自测等各个功能模块.对系统的数据库访问及在其间存在的安全性问题做了探讨,对系统的数据通信处理问题以及关于Java的双通道Socket通路的实现办法和机制进行了详细说明,同时对三层结构的答疑系统在服务器端和客户端的消息设计等一些关键技术做了具体介绍,对系统的用户界面如教师答疑界面、学生提问等一些重要界面进行了介绍,并给出了系统开发重要环节的设计过程和系统最后运行结果的一些重要界面.测试结果表明,系统运行稳定、结果准确、能够对日常的教学工作起到一定的帮助作用. 相似文献
38.
Run Wang Hengyang Xiang Yan Li Yihui Zhou Qingsong Shan Yuqin Su Zhi Li Yongjin Wang Haibo Zeng 《Advanced functional materials》2023,33(21):2215189
Perovskite light-emitting diodes (PeLEDs) show promising prospects in the wide color gamut display owing to their ultra-narrow full width at half maximum (FWHM). However, up to now, all perovskite white LEDs integrated by standard red, green, and blue perovskite emitters, namely, monolithic white PeLEDs (WPeLEDs), have been rarely reported, owing to facing some issues, e.g., solvent incompatibility in solution technique, ion exchange, and energy transfer between different emission centers. Herein, centered on these issues, an optimal intermediate connection layer (ICL) of Po-T2T/LiF/Ag/HAT-CN/MoO3 is adopted to successfully develop monolithic tandem multicolor PeLEDs and WPeLEDs for the first time. The multicolor PeLEDs can achieve the best external quantum efficiency of 1.8% and the highest luminance of 4844 cd m−2. Besides, the red/green/blue (R/G/B) monolithic tandem WPeLED shows a standard white International Commission on Illumination coordinate of (0.33, 0.33) and achieves an extremely wide color gamut reaching National Television Standards Committee of 130%. This study is the first to realize the standard R/G/B co-electroluminescence in a monolithic perovskite device and offers a feasible strategy for developing wide-color gamut perovskite displays. 相似文献
39.
Lisi Yang Shuaishuai Shen Xiang Chen Huan Wei Dongdong Xia Chaowei Zhao Ningfang Zhang Yuanyuan Hu Weiwei Li Hao Xin Jinsheng Song 《Advanced functional materials》2023,33(36):2303603
The electron transport layer (ETL) is a critical component in achieving high device performance and stability in organic solar cells. Conjugated polyelectrolytes (CPEs) have become an attractive alternative due to film-forming properties and ease of preparation. However, p-type CPEs generally exhibit poor charge mobility and conductivity, incorporation of electron-withdrawing units forming alternated D-A conjugated backbone can make up for these deficiencies. Herein, the ratio of electron withdrawing moieties are further increased and two poly(A1-alt-A2) typed PIIDNDI-Br and PDPPNDI-Br based on the combination of naphthalene diimide (NDI) with isoindigo (IID) or diketopyrrolopyrrole (DPP) via direct arylation polycondensation are synthesized. These CPEs possess excellent alcohol solubility, a suitable lowest unocuppied molecular orbital energy level, and work function tunability. Surprisingly, the incorporation of IID and DPP units generate distinct self-doping behaviors, which are confirmed by UV–vis absorption and ESR spectra. However, no matter doped or undoped, both CPEs present better charge-transporting properties and conductivity when utilized as ETLs. The PIIDNDI-Br and PDPPNDI-Br display good universal compatibility with the blend of PM6:Y6 and PM6:L8-BO, and PCEs of 18.32% and 18.36% are obtained, respectively, which also present excellent storage stability. In short, the combination of two different acceptors demonstrates an efficient strategy to design highly efficient ETLs for high performance photovoltaic devices. 相似文献
40.
Heng Zhao Jingwei Xue Hongbo Wu Baojun Lin Yuhang Cai Ke Zhou Daqin Yun Zheng Tang Wei Ma 《Advanced functional materials》2023,33(5):2210534
The power conversion efficiency (PCE) of organic solar cells (OSCs) has reached high values of over 19%. However, most of the high-efficiency OSCs are fabricated by spin-coating with toxic solvents and the optimal photoactive layer thickness is limited to 100 nm, limiting practical development of OSCs. It is a great challenge to obtain ideal morphology for high-efficiency thick-film OSCs when using non-halogenated solvents due to the unfavorable film formation kinetics. Herein, high-efficiency ternary thick-film (300 nm) OSCs with PCE of 15.4% based on PM6:BTR-Cl:CH1007 are fabricated by hot slot-die coating using non-halogenated solvent (o-xylene) in the air. Compared to PM6:BTR-Cl:Y6 blends, the stronger pre-aggregation of CH1007 in solution induces the earlier aggregation of CH1007 molecules and longer aggregation time, and thus results in high and balanced crystallinity of donors and acceptor in CH1007-based ternary film, which led to high-carrier mobility and suppressed charge recombination. The ternary strategy is further used to fabricate high-efficiency, thick-film, large-area, and flexible devices processed from non-halogenated solvents, paving the way for industrial development of OSCs. 相似文献