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非共价改性石墨烯的制备及环氧树脂复合材料导热性能
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作者 董育民 姜昀良 +3 位作者 熊勇 周建萍 胡智为 梁红波 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2024年第3期143-152,共10页
采用非共价键表面修饰制备了聚乙烯吡咯烷酮(PVP)改性的石墨烯(GR@PVP),通过共混方式将其作为填料与环氧树脂(EP)复合得到了不同填充量的EP/GR复合材料。红外光谱和热重分析结果表明,聚乙烯吡咯烷酮成功接枝到石墨烯表面。动态力学热分... 采用非共价键表面修饰制备了聚乙烯吡咯烷酮(PVP)改性的石墨烯(GR@PVP),通过共混方式将其作为填料与环氧树脂(EP)复合得到了不同填充量的EP/GR复合材料。红外光谱和热重分析结果表明,聚乙烯吡咯烷酮成功接枝到石墨烯表面。动态力学热分析和热性能测试结果表明,EP/GR@PVP复合材料的储能模量、玻璃化转变温度和损耗因子峰高度均比EP/GR复合材料有所降低,表明聚乙烯吡咯烷酮增强了环氧树脂复合材料的柔韧性。采用扫描电子显微镜观察复合材料断面形貌,GR@PVP在环氧树脂中分散均匀,且与基体相容性好。当填料质量分数为2.0%时,EP/GR@PVP复合材料的热导率比纯EP和EP/GR复合材料分别提高了205.3%和52.6%,25℃EP复合材料的表观黏度为13.29 Pa·s,符合电子封装材料对复合材料加工黏度的需求(<20 Pa·s)。其研究为进一步制备高导热、低黏度的电子封装材料提供了一种简便的方法。 展开更多
关键词 石墨烯 环氧树脂 聚乙烯吡咯烷酮 复合材料 导热
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Simultaneously mastering operando strain and reconstruction effects via phase-segregation strategy for enhanced oxygen-evolving electrocatalysis 被引量:1
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作者 Daqin Guan Chenliang Shi +6 位作者 Hengyue Xu Yuxing Gu Jian Zhong Yuchen Sha zhiwei hu Meng Ni Zongping Shao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期572-580,I0012,共10页
Material strain and reconstruction effects are critical for catalysis reactions,but current insights into operando strain effects during reaction and means to master catalyst reconstruction are still lacking.Here,we p... Material strain and reconstruction effects are critical for catalysis reactions,but current insights into operando strain effects during reaction and means to master catalyst reconstruction are still lacking.Here,we propose a facile thermal-induced phase-segregation strategy to simultaneously master material operando strain and reconstruction effects for enhanced oxygen-evolving reaction(OER).Specifically,self-assembled and controllable layered LiCoO_(2)phase and Co_(3)O_(4)spinel can be generated from pristine Li2Co_(2)O_(4)spinel via Li and O volatilization under different temperatures,realizing controllable proportions of two phases by calcination temperature.Combined operando and ex-situ characterizations reveal that obvious tensile strain along(003)plane appears on layered LixCoO_(2)phase during OER,while low-valence Co_(3)O_(4)phase transforms into high-valence CoOOHx,realizing simultaneous operando strain and reconstruction effects.Further experimental and computational investigations demonstrate that both strained LixCoO_(2)phase and reconstructed CoOOHxcompound contribute to the beneficial adsorption of important OH-reactants,while respective roles in activity and stability are uncovered by exploring their latticeoxygen participation mechanism.This work not only reveals material operando strain effects during OER,but also inaugurates a new thermal-induced phase-segregation strategy to artificially master material operando strain and reconstruction effects,which will enlighten rational material design for many potential reactions and applications. 展开更多
关键词 Operando strain Structural reconstruction Phase-segregation strategy Operando synergistic effects Oxygen-evolving reaction
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Enhanced H_(2) permeation and CO_(2) tolerance of self-assembled ceramic-metal-ceramic BZCYYb-Ni-CeO_(2) hybrid membrane for hydrogen separation
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作者 Jianqiu Zhu Jingzeng Cui +11 位作者 Yuxuan Zhang Ze Liu Chuan Zhou Susu Bi Jingyuan Ma Jing Zhou zhiwei hu Tao Liu Zhi Li Xiangyong Zhao Jian-Qiang Wang Linjuan Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期47-55,I0002,共10页
Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming ba... Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism.Exploring cost-effective membrane materials that can achieve both high H_(2) permeability and strong CO_(2)-tolerant chemical stability has been a major challenge for industrial applications.Herein,we constructed a triple phase(ceramic-metal-ceramic)membrane composed of a perovskite ceramic phase BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb),Ni metal phase and a fluorite ceramic phase CeO_(2).Under H_(2) atmosphere,Ni metal in-situ exsolved from the oxide grains,and decorated the grain surface and boundary,thus the electronic conductivity and hydrogen separation performance can be promoted.The BZCYYbNi-CeO_(2)hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min^(-1)cm^(-2) at 800℃ under a 10 vol% H_(2) atmosphere,surpassing all other perovskite membranes reported to date.Furthermore,the CeO_(2) phase incorporated into the BZCYYb-Ni effectively improved the CO_(2)-tolerant chemical stability.The BZCYYbNi-CeO_(2) membrane exhibited outstanding long-term stability for at least 80 h at 700℃ under 10 vol%CO_(2)-10 vol%H_(2).The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO_(2) resistance stability. 展开更多
关键词 Hydrogen separation Triple phase hybrid membrane Mixed proton-electron conductor Chemical stability X-ray absorption spectra
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In operando-formed interface between silver and perovskite oxide for efficient electroreduction of carbon dioxide to carbon monoxide
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作者 Xinhao Wu Yanan Guo +11 位作者 Yuxing Gu Fenghua Xie Mengran Li zhiwei hu Hong-Ji Lin Chih-Wen Pao Yu-Cheng huang Chung-Li Dong Vanessa KPeterson Ran Ran Wei Zhou Zongping Shao 《Carbon Energy》 SCIE CSCD 2023年第4期81-93,共13页
Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic perf... Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces. 展开更多
关键词 electrochemical CO_(2)reduction faradaic efficiencies interfaces perovskite oxides
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基于 DDES 算法的有扰流片腔体气动噪声分析 被引量:7
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作者 刘瑜 童明波 zhiwei hu 《空气动力学学报》 CSCD 北大核心 2015年第5期643-648,共6页
为了进一步了解腔体流场的物理特性以及锯齿形扰流片这种被动控制方法对腔体噪声振荡的抑制效果,对马赫数0.85下、长深比为5∶1的矩形腔体进行了气动声学分析。分析过程采用了基于Spalart-Allmaras单方程模型的延迟分离涡模拟(DDES)的CF... 为了进一步了解腔体流场的物理特性以及锯齿形扰流片这种被动控制方法对腔体噪声振荡的抑制效果,对马赫数0.85下、长深比为5∶1的矩形腔体进行了气动声学分析。分析过程采用了基于Spalart-Allmaras单方程模型的延迟分离涡模拟(DDES)的CFD方法。计算结果以声压级(SPL)形式与英国QinetiQ基地进行的实验研究结果进行比较。计算准确地预测出了第二阶和第三阶主导模态的声调噪声幅值,其误差均不超过2dB。为了验证腔体前缘安装扰流片这种广泛应用的腔体噪声被动控制方法,计算重点分析了带有锯齿形扰流片的腔体结构噪声等级。计算分析结果与空腔结果对比分析后认为前缘锯齿形扰流片可以降低第二阶主导模态的峰值噪声等级10dB以上,其它频率下的腔体噪声等级可降低接近5dB,降噪效果较好。 展开更多
关键词 腔体 气动噪声 扰流片 声压级 DDES
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Sr掺杂钙钛矿体系中高活性氧析出反应机制(英文) 被引量:2
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作者 宋三召 周靖 +6 位作者 孙健 张诗雨 林逍 zhiwei hud 胡钧 张林娟 王建强 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第4期592-597,共6页
析氧反应(oxygen evolutionreaction OER)是电催化分解水、二氧化碳还原、金属-空气电池以及燃料电池等能源转化及存储技术的关键过程,因此被广泛关注和研究.OER过程涉及四个电子转移,是动力学迟滞过程,具有较大的过电位,此外OER催化反... 析氧反应(oxygen evolutionreaction OER)是电催化分解水、二氧化碳还原、金属-空气电池以及燃料电池等能源转化及存储技术的关键过程,因此被广泛关注和研究.OER过程涉及四个电子转移,是动力学迟滞过程,具有较大的过电位,此外OER催化反应的同时也可能改变电极表面状态,故其机理的研究十分困难.设计和开发高效OER催化剂材料是提高电解水效率的关键.最近的研究发现反应后催化剂表面会发生重构,进而形成无定形层,该无定形层被认为会改善催化活性.我们的前期研究也发现了表面不饱和配位无定形层的存在,但对于重构机制尚没有明确的解释.本文在上述研究基础上,利用熔盐法合成了一系列具有多孔结构的不同Sr含量的LaCo0.8Fe0.2O3-δ钙钛矿材料,通过电化学装置测试其催化活性,并采用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电镜(HRTEM)、比表面积测试(BET)和软硬X射线吸收谱技术等表征手段对其进行了深入探索.XRD测试结果表明,Sr掺杂LaCo0.8Fe0.2O3-δ钙钛矿材料的主峰随着Sr含量增加向低角度偏移,这是由于Sr的离子半径较La的大.SEM和BET测试结果表明,不同Sr含量样品均表现出多孔的钙钛矿结构,并具有相似的比表面积,说明Sr含量变化不影响催化剂的形貌和比表面积.利用硬X射线吸收谱对体相Co和Fe元素的价态进行了研究,发现随着Sr含量的增加,Co和Fe离子的价态没有明显变化.类似地,利用软X射线吸收谱对表面层Co和Fe价态进行的研究发现,Co和Fe均表现出+3价,但在氧元素的K边吸收谱上观察到明显的氧空穴存在.电化学测试结果表明,催化剂的活性随Sr含量增加而增大.总之,随着Sr的掺杂,催化剂形貌及活性元素价态均无明显变化,但样品的电化学性能却发生了明显改善,这意味着尚有其它因素影响催化剂活性.利用HRTEM对OER反应前后的样品进行了形貌分析,发现在OER反应后Sr掺杂的催化剂表面出现了明显的无定形层,而无Sr掺杂的样品反应前后几乎未观察到表面形貌的变化.由此我们推断,Sr掺杂可诱导催化剂表面出现无定形层,进而提高OER反应活性.因此,在LaCo0.8Fe0.2O3-δ钙钛矿材料体系中,Sr掺杂是影响OER催化剂表面重构和制约催化活性的关键. 展开更多
关键词 熔盐法 钙钛矿 氧析出反应 表面重构 氧空穴
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Effect of cavity flow control on high-speed train pantograph and roof aerodynamic noise 被引量:12
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作者 Hogun Kim zhiwei hu David Thompson 《Railway Engineering Science》 2020年第1期54-74,共21页
The pantograph and its recess on the train roof are major aerodynamic noise sources on high-speed trains.Reducing this noise is particularly important because conventional noise barriers usually do not shield the pant... The pantograph and its recess on the train roof are major aerodynamic noise sources on high-speed trains.Reducing this noise is particularly important because conventional noise barriers usually do not shield the pantograph.However,less attention has been paid to the pantograph recess compared with the pantograph.In this paper,the flow features and noise contribution of two types of noise reduction treatments rounded and chamfered edges are studied for a simplified high-speed train pantograph recess,which is represented as a rectangular cavity and numerically investigated at 1/10 scale.Improved delayed detached-eddy simulations are performed for the near-field turbulent flow simulation,and the Ffowcs Williams and Hawkings aeroacoustic analogy is used for far-field noise prediction.The highly unsteady flow over the cavity is significantly reduced by the cavity edge modifications,and consequently,the noise radiated from the cavity is reduced.Furthermore,effects of the rounded cavity edges on the flow and noise of the pantographs(one raised and one folded)are investigated by comparing the flow features and noise contributions from the cases with and without rounding of the cavity edges.Different train running directions are also considered.Flow analysis shows that the highly unsteady flow within the cavity is reduced by rounding the cavity edges and a slightly lower flow speed occurs around the upper parts of the raised pantograph,whereas the flow velocity in the cavity is slightly increased by the rounding.Higher pressure fluctuations occur on the folded pantograph and the lower parts of the raised pantograph,whereas weaker fluctuations are found on the panhead of the raised pantograph.This study shows that by rounding the cavity edges,a reduction in radiated noise at the side and the top receiver positions can be achieved.Noise reductions in the other directions can also be found. 展开更多
关键词 High-speed TRAIN Aeroacoustics PANTOGRAPH PANTOGRAPH RECESS CAVITY flow Noise CONTROL
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Viral vectors as a novel tool for clinical and neuropsychiatric research applications 被引量:2
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作者 Yao Wang zhiwei hu +4 位作者 Peijun Ju Shan Yin Fujie Wang Oudong Pan Jinghong Chen 《General Psychiatry》 CSCD 2018年第5期100-108,共9页
Background A viral vector is a genetically modified vector produced by genetic engineering. As pathogenic genes in the virus are completely or largely eliminated, it is safe to be widely used in multidisciplinary rese... Background A viral vector is a genetically modified vector produced by genetic engineering. As pathogenic genes in the virus are completely or largely eliminated, it is safe to be widely used in multidisciplinary research fields for expressing genes, such as neuroscience, metabolism, oncology and so on. Neuroscience and psychiatry are the most closely related disciplines in either basic research or clinical research, but the application of viral vectors in neuropsychiatry has not received much attention or not been widely accepted.Aim This article will focus on the application of viral vectors in basic and clinical neuropsychiatric research.Methods By using viral vectors, scientists can perform neurological labelling, gene expression regulation and physiological manipulation for investigating phenomenon from molecular mechanisms to behaviours. At the same time, to treat mental or neurological disorders, viral vectors can be designed for gene therapy, which alter gene expression levels or repair mutated genes in the brains of patients.Perspective Viral vectors play an important role in basic research and clinical applications. To further understand brain function and prevent mental and neurological diseases, we hypothesize that viral vectors could be used along with various advanced technologies, such as sequencing and high-throughput expression analysis in the neuroscience research field. 展开更多
关键词 Methods By using VIRAL VECTORS NEUROSCIENCE and PSYCHIATRY
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On the origin of the anomalous sign reversal in the Hall effect in Nb thin films
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作者 周丹 曾寒松 +4 位作者 汤如俊 杭志宏 胡志伟 裴子玺 凌新生 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期527-532,共6页
We re-visit the anomalous sign reversal problem in the Hall effect of the sputtered Nb thin films. We find that the anomalous sign reversal in the Hall effect is extremely sensitive to a small tilting of the magnetic ... We re-visit the anomalous sign reversal problem in the Hall effect of the sputtered Nb thin films. We find that the anomalous sign reversal in the Hall effect is extremely sensitive to a small tilting of the magnetic field and to the magnitude of the applied current. Large anomalous variations are also observed in the symmetric part of the transverse resistance R_(xy).We suggest that the surface current loops on superconducting grains at the edges of the superconducting thin films may be responsible for the Hall sign reversal and the accompanying anomalous effects in the symmetric part of R_(xy). 展开更多
关键词 anomalous sign reversal Hall effect edge supercurrents Aharonov–Bohm effect
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Overcome the Impairment of NK Cells for Icon and Antibody Immunotherapy of Cancer
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作者 zhiwei hu 《Journal of Immune Based Therapies, Vaccines and Antimicrobials》 2013年第1期1-8,共8页
Natural killer (NK) cells play an important role in innate immunity and in mediating antibody and Icon (an antibody-like factor VII/IgG1 Fc immunoconjugate, which, to our best knowledge, was the first therapeutic agen... Natural killer (NK) cells play an important role in innate immunity and in mediating antibody and Icon (an antibody-like factor VII/IgG1 Fc immunoconjugate, which, to our best knowledge, was the first therapeutic agent for dual targeting of both the tumor cells and tumor angiogenic endothelial cells) for cancer immunotherapy. However, a common yet often neglected observation and challenge in antibody immunotherapy is that NK cells are often impaired in cancer patients. Here we hypothesize that the impairment of NK cells significantly contributes to host resistance to antibody immunotherapy for cancer. In order for antibody and Icon to achieve their optimal therapeutic efficacy, we briefly reviewed the current strategies to enhance NK activity, including infusion of cytokines, vaccines or NK cells, and the use of dietary supplements. Moreover, from our point of view we identified some remaining challenges and propose to combine these NK-enhancing strategies with Icon or antibody to overcome NK impairment and ultimately to optimize the efficacy of Icon and antibody immunotherapy for cancer. 展开更多
关键词 Natural KILLER Cells Antibody CANCER IMMUNOTHERAPY ICON Dietary SUPPLEMENTS
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Pd single atoms cooperate with S vacancies in ZnIn_(2)S_(4) nanosheets for photocatalytic pure-water splitting
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作者 Lin Sun huiping Peng +7 位作者 Fei Xue Shangheng Liu zhiwei hu Hongbo Geng Xiaozhi Liu Dong Su Yong Xu Xiaoqing huang 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第3期855-861,共7页
Photocatalytic water splitting has emerged as a new frontier for converting solar energy to green H_(2) and value-added chemicals.Nevertheless,great challenges still remain for developing efficient photocatalysts for ... Photocatalytic water splitting has emerged as a new frontier for converting solar energy to green H_(2) and value-added chemicals.Nevertheless,great challenges still remain for developing efficient photocatalysts for pure water splitting without sacrificial agents.In this work,we demonstrate that doping hexagonal ZnIn_(2)S_(4)(ZIS) with Pd single atoms(Pd_(0.03)/ZIS) can serve as a highly efficient photocatalyst for pure water splitting to simultaneously produce H_(2) and H_(2)O_(2) without any sacrificial agents.Results from aberration-corrected high-angle annular dark field scanning transmission electron microscopy,X-ray fine spectroscopy,insitu electron paramagnetic resonance and diffuse Fourier transform infrared spectroscopy reveal that doping ZIS with Pd single atoms facilitates the formation of S vacancies(S_(v)),where the photogenerated electrons can transfer to Pd single atoms,as a result of enhanced separation of electron-hole pairs and improved photocatalytic performance.Impressively,Pd_(0.03)/ZIS displays a stoichiometric ratio of H_(2) and H_(2)O_(2) with the productivity of 1,037.9 and 1,021.4μmol g^(-1)h^(-1),respectively,which has largely outperformed pure ZIS and other reported catalysts for pure water splitting.This work provides an efficient photocatalyst for water splitting to produce H_(2) and H_(2)O_(2),which may attract rapid interest in materials science,chemistry,and heterogeneous catalysis. 展开更多
关键词 ZnIn_(2)S_(4) Pd single atom S vacancy pure water splitting H_(2)O_(2)
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Antimony oxides-protected ultrathin Ir-Sb nanowires as bifunctional hydrogen electrocatalysts
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作者 Bingyan Xu Xuan huang +6 位作者 Shangheng Liu zhiwei hu Cheng-Wei Kao Ting-Shan Chan Hongbo Geng Ying Zhang Xiaoqing huang 《Nano Research》 SCIE EI CSCD 2024年第3期1042-1049,共8页
Developing electrocatalysts with fast kinetics and long-term stability for alkaline hydrogen oxidation reaction(HOR)and hydrogen evolution reaction(HER)is of considerable importance for the industrial production of gr... Developing electrocatalysts with fast kinetics and long-term stability for alkaline hydrogen oxidation reaction(HOR)and hydrogen evolution reaction(HER)is of considerable importance for the industrial production of green and sustainable energy.Here,an ultrathin Ir-Sb nanowires(Ir-Sb NWs)protected by antimony oxides(SbO_(x))was synthesized as an efficient bifunctional catalyst for both HOR and HER under alkaline media.Except from the much higher mass activities of Ir-Sb nanowires than those of Ir nanowires(Ir NWs)and commercial Pt/C,the SbO_(x) protective layer also contributes to the maintenance of morphology and anti-CO poisoning ability,leading to the long-term cycling performance in the presence of CO.Specifically,the Ir-Sb NW/SbO_(x) exhibits the highest catalytic activities,which are about 3.5 and 4.8 times to those of Ir NW/C and commercial Pt/C toward HOR,respectively.This work provides that the ultrathin morphology and H_(2)O-occupied Sb sites can exert the intrinsic high activity of Ir and effectively optimize the absorption of OH*both in alkaline HER/HOR electrolysis. 展开更多
关键词 Ir nanowire amorphous antimony oxides bifunctional mechanism hydrogen evolution reaction hydrogen oxidation reaction
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Ultrathin,flexible,and oxidation-resistant MXene/graphene porous films for efficient electromagnetic interference shielding 被引量:3
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作者 Xinwei Tang Jiangtao Luo +9 位作者 zhiwei hu Shijie Lu Xiaoyi Liu Shuangshuang Li Xu Zhao Zihang Zhang Qianqian Lan Piming Ma Zicheng Wang Tianxi Liu 《Nano Research》 SCIE EI CSCD 2023年第1期1755-1763,共9页
Designing and fabricating efficient electromagnetic interference(EMI)shielding materials becomes a significant and urgent concern.Hence,a novel ultrathin,flexible,and oxidation-resistant MXene-based graphene(M-rGX)por... Designing and fabricating efficient electromagnetic interference(EMI)shielding materials becomes a significant and urgent concern.Hence,a novel ultrathin,flexible,and oxidation-resistant MXene-based graphene(M-rGX)porous film is successfully fabricated by electrostatic self-assembly between MXene and graphene oxide(GO)nanosheets,and subsequently thermal annealing under hydrogen-argon atmosphere.The rapid breakaway of functional groups on GO and MXene sheets induces formation of porous conductive network in film,thereby facilitating efficient shielding for incident electromagnetic waves.The optimal absolute shielding effectiveness(SSE/t)value of 76,422 dB·cm2·g−1 can be achieved at a thinner thickness of 15μm.More importantly,the effective removal of functional groups on MXene conspicuously improves the oxidation resistance of the film,endowing it with an excellent durability(12 months)in EMI shielding performance. 展开更多
关键词 MXene GRAPHENE porous film oxidation resistance electromagnetic interference shielding
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Concurrent channel and spatial attention in Fully Convolutional Network for individual pig image segmentation 被引量:1
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作者 zhiwei hu hua Yang +1 位作者 Tiantian Lou Hongwen Yan 《International Journal of Agricultural and Biological Engineering》 SCIE CAS 2023年第1期232-242,共11页
The separation of individual pigs from the pigpen scenes is crucial for precision farming,and the technology based on convolutional neural networks can provide a low-cost,non-contact,non-invasive method of pig image s... The separation of individual pigs from the pigpen scenes is crucial for precision farming,and the technology based on convolutional neural networks can provide a low-cost,non-contact,non-invasive method of pig image segmentation.However,two factors limit the development of this field.On the one hand,the individual pigs are easy to stick together,and the occlusion of debris such as pigpens can easily make the model misjudgment.On the other hand,manual labeling of group-raised pig data is time-consuming and labor-intensive and is prone to labeling errors.Therefore,it is urgent for an individual pig image segmentation model that can perform well in individual scenarios and can be easily migrated to a group-raised environment.In order to solve the above problems,taking individual pigs as research objects,an individual pig image segmentation dataset containing 2066 images was constructed,and a series of algorithms based on fully convolutional networks were proposed to solve the pig image segmentation problem.In order to capture the long-range dependencies and weaken the background information such as pigpens while enhancing the information of individual parts of pigs,the channel and spatial attention blocks were introduced into the best-performing decoders UNet and LinkNet.Experiments show that using ResNext50 as the encoder and Unet as the decoder as the basic model,adding two attention blocks at the same time achieves 98.30%and 96.71%on the F1 and IOU metrics,respectively.Compared with the model adding channel attention block alone,the two metrics are improved by 0.13%and 0.22%,respectively.The experiment of introducing channel and spatial attention alone shows that spatial attention is more effective than channel attention.Taking VGG16-LinkNet as an example,compared with channel attention,spatial attention improves the F1 and IOU metrics by 0.16%and 0.30%,respectively.Furthermore,the heatmap of the feature of different layers of the decoder after adding different attention information proves that with the increase of layers,the boundary of pig image segmentation is clearer.In order to verify the effectiveness of the individual pig image segmentation model in group-raised scenes,the transfer performance of the model is verified in three scenarios of high separation,deep adhesion,and pigpen occlusion.The experiments show that the segmentation results of adding attention information,especially the simultaneous fusion of channel and spatial attention blocks,are more refined and complete.The attention-based individual pig image segmentation model can be effectively transferred to the field of group-raised pigs and can provide a reference for its pre-segmentation. 展开更多
关键词 PIG image segmentation Fully Convolutional Network(FCN) attention mechanism channel and spatial attention
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碱金属离子诱导亚稳相钌纳米晶合成
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作者 张俊涛 刘效知 +6 位作者 陈立刚 曹茂丰 李晓彤 苏东 胡志伟 徐勇 黄小青 《Science Bulletin》 SCIE EI CAS CSCD 2023年第23期2924-2928,M0004,共6页
亚稳相金属纳米晶因其优异的物理化学性质备受关注,然而如何可控合成亚稳相结构依然面临诸多挑战.本文报道了碱金属离子诱导亚稳相钌纳米晶(面心立方相)的可控合成策略.研究表明钌纳米晶结构和碱金属离子半径密切相关,因此通过改变碱金... 亚稳相金属纳米晶因其优异的物理化学性质备受关注,然而如何可控合成亚稳相结构依然面临诸多挑战.本文报道了碱金属离子诱导亚稳相钌纳米晶(面心立方相)的可控合成策略.研究表明钌纳米晶结构和碱金属离子半径密切相关,因此通过改变碱金属离子实现了面心立方相和六方密堆相比例的连续调控.理论计算结果表明,碱金属的存在导致面心立方相的形成能低于六方密堆相,并且这种能量差随着碱金属离子半径的增大而增大.本工作为拓展亚稳态结构的实际应用奠定了基础. 展开更多
关键词 亚稳相 碱金属离子 面心立方 纳米晶结构 金属纳米晶 物理化学性质 可控合成
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Revealing the importance of suppressing formation of lithium hydride and hydrogen in Li anode protection
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作者 Gaojie Xu Xiaofan Du +4 位作者 Shenghang Zhang Jiedong Li Shanmu Dong zhiwei hu Guanglei Cui 《Interdisciplinary Materials》 2023年第2期337-347,共11页
The reviving of the“Holy Grail”lithium metal batteries(LMBs)is greatly hindered by severe parasitic reactions between Li anode and electrolytes.Herein,first,we comprehensively summarize the failure mechanisms and pr... The reviving of the“Holy Grail”lithium metal batteries(LMBs)is greatly hindered by severe parasitic reactions between Li anode and electrolytes.Herein,first,we comprehensively summarize the failure mechanisms and protection principles of the Li anode.Wherein,despite being in dispute,the formation of lithium hydride(LiH)is demonstrated to be one of the most critical factors for Li anode pulverization.Secondly,we trace the research history of LiH at electrodes of lithium batteries.In LMBs,LiH formation is suggested to be greatly associated with the generation of H_(2)from Li/electrolyte intrinsic parasitic reactions,and these intrinsic reactions are still not fully understood.Finally,density functional theory calculations reveal that H_(2)adsorption ability of representative Li anode protective species(such as LiF,Li_(3)N,BN,Li_(2)O,and graphene)is much higher than that of Li and LiH.Therefore,as an important supplement of well-known lithiophilicity theory/high interfacial energy theory and three key principles(mechanical stability,uniform ion transport,and chemical passivation),we propose that constructing an artificial solid electrolyte interphase layer enriched of components with much higher H_(2)adsorption ability than Li will serve as an effective principle for Li anode protection.In summary,suppressing formation of LiH and H_(2)will be very important for cycle life enhancement of practical LMBs. 展开更多
关键词 density functional theory H_(2)adsorption ability Li anode protection lithium hydride solid electrolyte interphase
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Insult of gastroesophageal reflux on airway: clinical significance of pharyngeal nozzle 被引量:22
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作者 Zhonggao Wang zhiwei hu +9 位作者 Jimin Wu Feng Ji Hongtao Wang Yungang Lai Xiang Gao Yachan Ning Chengchao Zhang Zhitong Li Weitao Liang Jianjun Liu 《Frontiers of Medicine》 SCIE CAS CSCD 2015年第1期117-122,共6页
At the very time of global paying the highest attention to the worst insults of smoking as well as haze on the airway, everybody knows both are exogenous and noticeable. However, people mostly, including many medical ... At the very time of global paying the highest attention to the worst insults of smoking as well as haze on the airway, everybody knows both are exogenous and noticeable. However, people mostly, including many medical personnel, do not know how badly the gastroesophageal reflux (GER) insults on our own airway. Symptoms of GER are commonly seen as heartburn and regurgitation, which can be mostly tolerated. However, when the up going gastric content reversely passes the esophagus and then the distal pharynx, where it appears a beak like stricture, serving as a nozzle, so as to produce numerous micro-particles and reach the oro-nasal cavity and also the airway causing allergic rhinitis and asthmatic attacks, even pulmonary parenchyma lesions. It will reduce life quality or even jeopardize life. The point that the endogenous insult appears in the respiratory system, but originates from the digestive tract is not well known and often undiagnosed and not correctly treated. The GER induced airway challenge is a treatable and preventive entity, as soon as a diagnosis is made, a good relief could be expected by means of life style adjustment, medicine, or fixation of the patulous cardia through radiofrequency or fundoplication. The author Dr. Zhonggao Wang had suffered it for long and symptoms disappeared for 8 years after anti-reflux surgery. Here is a presentation of Dr. Zhonggao Wang and his team's work and would call attention to the public so as to recognize this relatively unknown entity -- a treatable condition occurring from human itself, but not from outside surroundings as smoking or haze does. 展开更多
关键词 gastroesophageal reflux AIRWAY pharyngeal nozzle micro-aspiration ASTHMA
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Outcome of Stretta radiofrequency and fundoplication for GERD- related severe asthmatic symptoms 被引量:10
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作者 zhiwei hu Jimin Wu +3 位作者 Zhonggao Wang Yu Zhang Weitao Liang Chao Yan 《Frontiers of Medicine》 SCIE CAS CSCD 2015年第4期437-443,共7页
This study aimed to investigate the outcome of treatment with Stretta radiofrequency (SRF) or laparoscopic Nissen fundoplication (LNF). A total of 137 gastroesophageal reflux disease (GERD) patients with severe ... This study aimed to investigate the outcome of treatment with Stretta radiofrequency (SRF) or laparoscopic Nissen fundoplication (LNF). A total of 137 gastroesophageal reflux disease (GERD) patients with severe asthmatic symptoms who responded inadequately to medical treatment for asthma were investigated. The patients were followed up 1 year and 5 years after SRF (n = 82) or LNF (n = 55) treatment. A questionnaire covering 29 related symptoms and medication use was employed. Digestive, respiratory, and ear-nose-throat (ENT) symptom scores significantly decreased after antireflux treatment. Symptom scores respectively changed from 17.2 ± 10.1, 31.9 ± 6.6, and 21.1± 11.8 to 5.0 ±6.2, 11.5 ±10.2, and 6.3± 6.8 at 1 year and to 5.6 ± 6.5, 13.1± 10.1, and 7.8 ± 7.2 at 5 years (P 〈 0.001). The outcome of LNF was significantly better than that of SRF in terms of digestive (P 〈 0.001, P = 0.001), respiratory (P = 0.006, P = 0.001), and ENT symptoms (P = 0.006, P = 0.003) at both 1 year and 5 years. SRF and LNF were both effective against the digestive symptoms of GERD as well as GERD-related severe asthmatic and ENT symptoms, with better outcomes exhibited by the LNF group. Severe asthmatic symptoms and GERD were closely associated, and this finding warrants further study. 展开更多
关键词 ASTHMA gastroesophageal reflux Stretta radiofrequency laparoscopic Nissen fundoplication
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Improved control of hypertension following laparoscopic fundoplication for gastroesophageal reflux disease 被引量:4
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作者 zhiwei hu Meiping Chen +4 位作者 Jimin Wu Qing Song Chao Yan Xing Du Zhonggao Wang 《Frontiers of Medicine》 SCIE CAS CSCD 2017年第1期68-73,共6页
This study aims to determine whether successful laparoscopic fundoplication for gastroesophageal reflux disease (GERD) can improve the control of hypertension. We conducted an observational study of GERD patients wi... This study aims to determine whether successful laparoscopic fundoplication for gastroesophageal reflux disease (GERD) can improve the control of hypertension. We conducted an observational study of GERD patients with hypertension. The esophageal and gastroesophageal symptoms of these patients were successfully treated with laparoscopic fundoplication, as measured by the reduced GERD symptoms and proton pump inhibitor consumption. A hypertension control scale was used to classify the use of antihypertensive medications and the quality of blood pressure control before and after anti-reflux surgery. Wilcoxon signed-ranks test was used for the statistical analyses. Seventy GERD patients were included in the analysis and followed up for a mean period of 3.5± 1.4 years. Prior to surgery, all participating patients were taking at least one class of antihypertensive medication, and 56 patients (80%) had intermittently high blood pressure. After surgery, the mean number of antihypertensive medication classes per patient was significantly reduced from 1.61 ± 0.77 pre-procedure to 1.27 ± 0.88 post-procedure (P 〈 0.001). The blood pressure of 48 of the 56 cases (86±) with preoperative intermittent high blood pressure returned to normal post procedure. A total of 50 patients (71%) recorded improvements on the hypertension control scale, with the overall mean score decreasing from 3.1 ± 1.0 pre- procedure to 1.4 ± 1.0 post-procedure (P 〈 0.001). Therefore, successful laparoscopic fundoplication may result in better blood pressure control in some hypertensive GERD patients. This result suggests a possible connection between gastroesophageal reflux and hypertension. 展开更多
关键词 gastroesophageal reflux disease HYPERTENSION blood pressure laparoscopic fundoplication
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Atomically isolated Pd sites within Pd-S nanocrystals enable trifunctional catalysis for direct,electrocatalytic and photocatalytic syntheses of H_(2)O_(2) 被引量:3
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作者 Tang Yang Chengyong Yang +10 位作者 Jiabo Le Zhiyong Yu Lingzheng Bu Leigang Li Shuxing Bai Qi Shao zhiwei hu Chih-Wen Pao Jun Cheng Yonggang Feng Xiaoqing huang 《Nano Research》 SCIE EI CSCD 2022年第3期1861-1867,共7页
Although high-efficiency production of hydrogen peroxide(H_(2)O_(2))can be realized separately by means of direct,electrochemical,and photocatalytic synthesis,developing versatile catalysts is particularly challenging... Although high-efficiency production of hydrogen peroxide(H_(2)O_(2))can be realized separately by means of direct,electrochemical,and photocatalytic synthesis,developing versatile catalysts is particularly challenging yet desirable.Herein,for the first time we reported that palladium-sulphur nanocrystals(Pd-S NCs)can be adopted as robust and universal catalysts,which can realize the efficient O_(2) conversion by three methods.As a result,Pd-S NCs exhibit an excellent selectivity(89.5%)to H_(2)O_(2)with high productivity(133.6 mol·kgcat^(−1)·h^(−1))in the direct synthesis,along with the significantly enhanced H_(2)O_(2)production activity and stability via electrocatalytic and photocatalytic syntheses.It is demonstrated that the isolated Pd sites can enhance the adsorption of O_(2) and inhibit its O–O bond dissociation,improving H_(2)O_(2)selectivity and reducing H_(2)O_(2)degradation.Further study confirms that the difference in surface atom composition and arrangement is the key factor for different ORR mechanisms on Pd NCs and Pd-S NCs. 展开更多
关键词 Pd-S UNIVERSALITY direct synthesis of H_(2)O_(2) oxygen reduction photocatalysis
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