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Microstructure and superconducting properties of (BaTiO3,Y2O3)-doped YBCO films under different firing temperatures

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Rare Metals 2017年第1期36卷 37-41页

作者： Hong-Yan Wang fa-zhu ding Hong-Wei Gu Hui-Liang Zhang Ze-Bin Dong University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Applied Superconductivity Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190 China

YBaCuO(YBCO) films with co-doping of Ba Ti O(BTO) and YOnanostructures were successfully fabricated on La Al O(LAO) substrate by metal organic deposition using trifluoroacetates(Tfa-MOD). The focus of this study was to optimize the process conditions during the firing heat treatment of high critical current density(J C)-co-doped YBCO films. The effect of the firing temperatures on both the surface morphology and the superconducting properties for the doped YBCO films was systematically studied. According to the X-ray diffraction(XRD) and scanning electron microscopy(SEM) results,the films prepared at 820 and 850 °C show poor electrical performance due to impurity phases and large pores. In contrast, the dense YBCO films prepared at 830 and840 °C with the critical current densities of 10 MA-cm(77 K, 0 T) are obtained.

关键词： YBa2Cu3O7-x BaTiO3 and Y2O3 nanostructures Firing temperature Tfa-MOD

Growth mechanism of CdS film prepared by chemical bath deposition

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Rare Metals 2014年第3期33卷 324-329页

作者： Xing-Yu Peng Hong-Wei Gu Teng Zhang fa-zhu ding Fei Qu Hong-Yan Wang Key Laboratory of Applied Superconductivity Institute of Electrical Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences

In this paper, sodium citrate was adopted as a complexing agent and ammonia merely served as pH adjustor to investigate the growth mechanism of CdS film The growth rate, structural properties, surface morphology microstructure, and optical properties of CdS films were studied by profilometer, X-ray diffractometer（XRD）scanning electron microscopy（SEM）, transmission elec tron microscopy（TEM）, and spectrophotometer, respec tively. The SEM images show that CdS films prepared with higher ammonia concentration have lower nucleation density on substrate. SEM and EDS results show that the formation of Cd（OH）2is not required in the growth of CdS film. As the ammonia concentration increases, the sites tha previously adsorbed S2-are taken by OH-which leads to lower S2-density on substrate. CdS film forms through direct reaction of Cd2？with the S2-which are adsorbed on the substrate. Lower S2-density on the substrate results in the decrease of particle density on the substrate. The as deposited CdS films have relatively high-average trans mittance（＊80 %） in the wavelength range from 500 to1,000 nm which makes them suitable to be used in sola cell.

关键词： CdS Chemical bath deposition Ammoniaconcentration Growth mechanism

Morphological evolution of CdS films prepared by chemical bath deposition

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Rare Metals 2013年第4期32卷 380-389页

作者： Xing-Yu Peng Hong-Wei Gu Teng Zhang Fei Qu fa-zhu ding Hong-Yan Wang Key Laboratory of Applied Superconductivity Institute of Electrical Engineering Chinese Academy of Sciences

In this article, the growth process of chemical bath deposited CdS films was systematically investigated. The structural, optical, and morphological properties were investigated by X-ray diffraction （XRD）, transmission electron microscope （TEM）, UV-Vis spectrophotometer, scanning electron microscope （SEM）, respectively. CdS nanocubes with size of less than 500 nm and nanocrystal-lites with diameter of less than 5 nm forming in reaction solution are observed. According to the TEM results and the SEM morphological evolution of CdS films, a crystal-lite-by-crystallite growth mechanism is proposed to eluci-date the growth process of chemical bath deposited CdS films based on the present growth mechanism.

关键词： CdS Chemical bath deposition Growthmechanism Crystallite-by-crystallite

Electrical and optical properties of ZnO:Al films with different hydrogen contents in sputtering gas

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Rare Metals 2015年第3期34卷 173-177页

作者： Fei Qu Teng Zhang Hong-Wei Gu Qing-Quan Qiu fa-zhu ding Xing-Yu Peng Hong-Yan Wang Applied Superconductors Key Laboratory Institute of Electrical EngineeringChinese Academy Sciences

Aluminum-doped zinc oxide （ZnO：AI） films were deposited by direct current magnetron sputtering in incorporating hydrogen in sputtering gas at room temper- ature. The influences of hydrogen content in sputtering gas on the structural, optical, and electrical properties of ZnO：A1 films were systematically investigated. It is found that hydrogen incorporated into ZnO lattice forms shallow donors in ZnO：A1 films and plays an important role in the properties of ZnO：A1 films. The electrical conductivity and infrared （IR） reflectance are improved due to the increase of electron carrier concentration, and the average trans- mittance decreases, which is ascribed to the strong scat- tering from the hydrogen incorporated and oxygen vacancies in ZnO：A1 films. In this study, the resistivity of 5.5 × 10-4 Ω.cm is obtained, the average transmittance of the wavelength in the range of 400-900 nm is almost 86 %, and the IR reflectance reaches 75 % at 2,500 nm, which is higher than that of reported TCO films. The band gap determined by optical absorption is a result of com- petition between Burstein-Moss effect and many-body perturbation effect. However, the hydrogen content in sputtering gas is above 10 %, and the optical band gap shift is independent of hydrogen content in sputtering gas.

关键词： ZnO:A1 thin films Hydrogen Electricalresistivity Transmittance IR reflectance

Substrate angle-induced fully c-axis orientation of AlN films deposited by off-normal DC sputtering method

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Rare Metals 2021年第12期40卷 3668-3675页

作者： Bo-Wei Xie fa-zhu ding Hong-Jing Shang Da-Xing Huang Tai-Guang Li Qi Zou Ji-Liang Zhang Hong-Wei Gu Key Laboratory of Applied Superconductivity Chinese Academy of SciencesBeijing 100190China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea

A highly c-axis-oriented aluminum nitride(Al N)thin film with smooth and crack-free surface was fabricated by an off-normal direct current(DC)sputtering method in a pure nitrogen atmosphere,in which the rotatable substrate holder positioned in the middle of four side targets was a key approach to guarantee the grain growth with no *** detailed effects of substrate angle on the c-axis orientation of Al N films were investigated by varying the substrate angle from 0°to 90°.Moreover,theoretical analysis and Monte Carlo(MC)simulation reveal that the oblique or even vertical angle could improve the lateral kinetic energy of sputtered atoms deposited on the growing film.A variety of examining techniques including X-ray diffraction(XRD),(002)peak rocking curve,scanning electron microscopy(SEM)were conducted to evaluate the angle dependence on the crystallographic *** test results indicate that larger substrate angle is beneficial to the(002)growth of Al N thin film,and a fully c-axis textured Al N thin film is obtained at 90°with small surface roughness(R_(a))of 3.32 nm.

关键词： AlN film c-axis orientation Off-normal DC sputtering Rotating substrate Side target

Emerging Flexible Thermally Conductive Films:Mechanism,fabrication,Application

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Nano-Micro Letters 2022年第8期14卷 24-57页

作者： Chang‑Ping Feng fang Wei Kai‑Yin Sun Yan Wang Hong‑Bo Lan Hong‑Jing Shang fa‑zhu ding Lu Bai Jie Yang Wei Yang Shandong Engineering Research Center for Additive Manufacturing Qingdao University of TechnologyQingdao 266520People’s Republic of China State Key Laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu 610065People’s Republic of China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190People’s Republic of China

Effective thermal management is quite urgent for electronics owing to their ever-growing integration degree,operation frequency and power density,and the main strategy of thermal management is to remove excess energy from electronics to outside by thermal conductive *** to the conventional thermal management materials,flexible thermally conductive films with high in-plane thermal conductivity,as emerging candidates,have aroused greater interest in the last decade,which show great potential in thermal management applications of next-generation ***,a comprehensive review of flexible thermally conductive films is rarely ***,we review recent advances of both intrinsic polymer films and polymer-based composite films with ultrahigh in-plane thermal conductivity,with deep understandings of heat transfer mechanism,processing methods to enhance thermal conductivity,optimization strategies to reduce interface thermal resistance and their potential ***,challenges and opportunities for the future development of flexible thermally conductive films are also discussed.

关键词： Thermal conductivity Flexible thermally conductive films Heat transfer mechanism Interface thermal resistance Thermal management applications

A review of vortex pinning in REBa_(2)Cu_(3)O_(7-x) coated conductors

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cMat 2024年第1期1卷 110-125页

作者： Tong-Xin Wang Da-Xing Huang fa-zhu ding Hao Dong Hao Yu Chao-Chao Dun Hong-Wei Gu Key Laboratory of Applied Superconductivity and Institute of Electrical Engineering Chinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina The Molecular Foundry Lawrence Berkeley National Laboratory BerkeleyBerkeleyCaliforniaUSA

REBa_(2)Cu_(3)O_(7-x)exhibits outstanding qualities such as a high irreversible field(7 T)and strong current-carrying capacity(77 K,10^(6) A cm^(-2)),making it ideal for high magnetic field applications such as fusion,accelerators,and nuclear magnetic ***,the degradation of in-field critical current density(Jc)due to vortex motion is a significant *** indicates that improving vortex pinning can notably enhance Jc in REBCO,showing promise for its future high-field *** review explores vortex pinning mecha-nisms,artificial pinning centers(APCs),and how environmental conditions affect pinning characteristics,highlighting advancements in vortex pinning for REBCO in magnetic *** methods for introducing APCs are discussed and compared for evaluating their efficacy in achieving optimal nanoparticle distri-butions and consequent superconducting performance improvements,under-scoring the importance of nano-defect features(type,size,and distribution)in optimizing the superconducting properties of the ***,the re-view tackles current challenges,shares recent research breakthroughs,and out-lines future research directions for designing pinning landscapes to further improve REBCO performance.

关键词： critical current density magnetic field REBCO vortex pinning

Rock fracture mechanism of buffer blasting with cushion layer at the borehole bottom

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 325-334页

作者： Xinguang zhu Chenxi ding Zhe Sui Hong Su Xu Guo School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Chemical and Blasting Engineering Anhui University of Science and TechnologyHuainan 232001China

This study primarily investigates the rock fracture mechanism of bottom cushion layer blasting and explores the effects of the bottom cushion layer on rock *** involves analyses of the evolution patterns of blasting stress,characteristics of crack distribution,and rock fracture features in the ***,blasting model experiments were carried out using the dynamic caustics principle to investigate the influence of bottom cushion layers and initiation methods on the integrity of the bottom rock *** experimental results indicate that the combined use of bottom cushion layers and inverse initiation effectively protects the integrity of the bottom rock ***,the process of stress wave propagation and dynamic crack propagation in rocks was simulated using the continuum-discontinuum element method(CDEM)and the Landau explosion source model,with varying thicknesses of bottom cushion *** numerical simulation results indicate that with increasing cushion thickness,the absorption of energy generated by the explosion becomes more pronounced,resulting in fewer cracks in the bottom rock *** illustrates the positive role of the cushion layer in protecting the integrity of the bottom rock mass.

关键词： bottom cushion layer blasting crack propagation continuum-discontinuum element method dynamic stress intensity factor

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高速公路软基处理中浮桩和薄硬夹层初步研究

山西建筑 2008年第28期34卷 12-13页

作者：朱发丁李小山浙江中医药大学总务处浙江理工大学建工学院土木系

在两个模型的基础上,针对水泥搅拌桩加固高速公路可能出现的浮桩情况研究了地基总沉降和未打穿土层厚度的关系;针对可能出现的薄硬夹层情况探讨了地基总沉降和中间薄硬夹层厚度的关系,并因此得出了一些对工程有益的结论。

关键词：水泥搅拌桩浮桩薄硬夹层地基沉降