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Dynamically observing the formation of MOFs-driven Co/N-doped carbon nanocomposites by in-situ transmission electron microscope and their application as high-efficient microwave absorbent

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Nano Research 2022年第8期15卷 6819-6830页

作者： You Zhou Xia Deng Hongna Xing Hongyang Zhao Yibo liu Lisong Guo Juan feng Wei feng Yan Zong Xiuhong Zhu Xinghua Li Yong Peng Xinliang Zheng School of Physics State Key Laboratory of Photoelectric Technology and Functional MaterialsNorthwest UniversityXi’an 710127China School of Materials and Energy Electron Microscopy Centre of Lanzhou UniversityLanzhou UniversityLanzhou 730000China School of Chemistry Xi’an Key Laboratory of Sustainable Energy Materials ChemistryXi’an Jiaotong UniversityXi’an 710049China

Metal-organic frameworks(MOFs)derived magnetic carbon-based nanocomposites have drawn widespread attentions due to the well distributed nanocrystals in carbon matrix.Dynamically observing the formation process is urgently needed.Herein,taking zeolitic imidazolate framework(ZIF)-67 as an example,the pyrolysis process is investigated by in-situ transmission electron microscopy(TEM)assisted with ex-situ characterizations.Co nanocrystals are evenly distributed in carbon at the initial stage of carbonization.By increasing pyrolysis temperature,the nanocrystals grow bigger and migrate to carbon surface.The carbon texture transfers from amorphous to crystalline at 600°C,and thoroughly converts at 800°C.In-situ heating TEM shows that more tiny Co nanocrystals move out from the carbon texture by increasing temperature from 700 to 800°C.At 1,000°C,some escaped tiny Co nanocrystals are volatilized and disappeared.The residual escaped Co nanocrystals catalyze the formation of carbon nanotubes(CNTs).Due to the synergistic effect between Co and carbon as well as porous structure,the nanocomposites show high-efficient microwave absorption performance,which can be tuned by pyrolysis temperature,heating rate,and mass fraction.When the mass fraction is 30 wt.%,the nanocomposites obtained at 600 or 700°C display remarkable microwave absorption with optimal reflection loss(RL)smaller than−70 dB and effective absorption band larger than 4.9 GHz.Combining the in-situ and ex-situ techniques,some key findings were observed:(1)graphitization of carbon;(2)volatilization of Co nanocrystals;(3)formation process of CNTs by Co catalyst.These findings are helpful to understand the formation of MOFs derived carbon-based composites and expand their practical applications,especially for microwave absorption.

关键词： metal-organic frameworks Co/N-doped carbon nanocomposites in-situ transmission electron microscopy(TEM) microwave absorption

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Highly Reversible Zn Metal Anodes Enabled by Increased Nucleation Overpotential

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Nano-Micro Letters 2023年第10期15卷 197-209页

作者： Zhengqiang Hu fengling Zhang Anbin Zhou Xin Hu Qiaoyi Yan Yuhao liu Faiza Arshad Zhujie Li Renjie Chen feng Wu Li Li Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081People’s Republic of China Collaborative Innovation Center of Electric Vehicles in Beijing Beijing 100081People’s Republic of China Advanced Technology Research Institute Beijing Institute of TechnologyJinan 250300People’s Republic of China

Dendrite formation severely compromises further development of zinc ion batteries. Increasing the nucleation overpotential plays a crucial role in achieving uniform deposition of metal ions. However, this strategy has not yet attracted enough attention from researchers to our knowledge. Here, we propose that thermodynamic nucleation overpotential of Zn deposition can be boosted through complexing agent and select sodium L-tartrate(Na-L) as example. Theoretical and experimental characterization reveals L-tartrate anion can partially replace H_(2)O in the solvation sheath of Zn^(2+), increasing de-solvation energy. Concurrently, the Na^(+) could absorb on the surface of Zn anode preferentially to inhibit the deposition of Zn^(2+) aggregation. In consequence, the overpotential of Zn deposition could increase from 32.2 to 45.1 mV with the help of Na-L. The Zn-Zn cell could achieve a Zn utilization rate of 80% at areal capacity of 20 mAh cm^(-2). Zn-LiMn_(2)O_(4) full cell with Na-L additive delivers improved stability than that with blank electrolyte. This study also provides insight into the regulation of nucleation overpotential to achieve homogeneous Zn deposition.

关键词： Nucleation overpotential Complexing agent Zn batteries Zn deposition

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Light-driven biohybrid system utilizes N2 for photochemical CO2 reduction

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National Science Review 2023年第7期10卷 159-171页

作者： Jin-Yue Zeng Xiao-Shuang Wang Xin-Hua liu Qian-Ru Li Jun feng Xian-Zheng Zhang Key Laboratory of Biomedical Polymers of Ministry of Education and Department of Chemistry Wuhan University Wuhan Research Centre for Infectious Diseases and Cancer Chinese Academy of Medical Sciences

Attempting to couple photochemical CO2reduction with N2fixation is usually difficult,because the reaction conditions for these two processes are typically incompatible.Here,we report that a light-driven biohybrid system can utilize abundant,atmospheric N2to produce electron donors via biological nitrogen fixation,to achieve effective photochemical CO2reduction.This biohybrid system is constructed by incorporating molecular cobalt-based photocatalysts into N2-fixing bacteria.It is found that N2-fixing bacteria can convert N2into reductive organic nitrogen and create a localized anaerobic environment,which allows the incorporated photocatalysts to continuously perform photocatalytic CO2reduction under aerobic conditions.Specifically,the light-driven biohybrid system displays a high formic acid production rate of over 1.41×10-14mol h-1cell-1under visible light irradiation,and the organic nitrogen content undergoes an over-3-fold increase within 48 hours.This work offers a useful strategy for coupling CO2conversion with N2fixation under mild and environmentally benign conditions.

关键词： biohybrid photocatalysis CO2 reduction nitrogen fixation bacterium

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Novel algorithm for detection and identification of radioactive materials in an urban environment

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Nuclear Science and Techniques 2023年第10期34卷 103-116页

作者： Hao-Lin liu Hai-Bo Ji Jiang-Mei Zhang Jing Lu Cao-Lin Zhang Xing-Hua feng Department of Automation University of Science and Technology of ChinaHefei 230026China School of Information Engineering Southwest University of Science and TechnologyMianyang 621010China Fundamental Science on Nuclear Wastes and Environment Safety Laboratory Southwest University of Science and TechnologyMianyang 621010China School of Automation and Information Engineering Sichuan University of Science and EngineeringZigong 643000China

This study introduces a novel algorithm to detect and identify radioactive materials in urban settings using time-series detector response data. To address the challenges posed by varying backgrounds and to enhance the quality and reliability of the energy spectrum data, we devised a temporal energy window. This partitioned the time-series detector response data, resulting in energy spectra that emphasize the vital information pertaining to radioactive materials. We then extracted characteristic features of these energy spectra, relying on the formation mechanism and measurement principles of the gammaray instrument spectrum. These features encompassed aggregated counts, peak-to-flat ratios, and peak-to-peak ratios. This methodology not only simplified the interpretation of the energy spectra's physical significance but also eliminated the necessity for peak searching and individual peak analyses. Given the requirements of imbalanced multi-classification, we created a detection and identification model using a weighted k-nearest neighbors(KNN) framework. This model recognized that energy spectra of identical radioactive materials exhibit minimal inter-class similarity. Consequently, it considerably boosted the classification accuracy of minority classes, enhancing the classifier's overall efficacy. We also executed a series of comparative experiments. Established methods for radionuclide identification classification, such as standard KNN, support vector machine, Bayesian network, and random tree, were used for comparison purposes. Our proposed algorithm realized an F1 measure of 0.9868 on the time-series detector response data, reflecting a minimum enhancement of 0.3% in comparison with other techniques. The results conclusively show that our algorithm outperforms others when applied to time-series detector response data in urban contexts.

关键词： Gamma-ray spectral analysis Nuclide identification Urban environment Temporal energy window Peakratio spectrum analysis Weighted KNN

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刮板输送机闸盘联接套铣用加工装置

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机械工程与自动化 2024年第1期 122-123页

作者：王凤鲜张少伟刘超宇山西煤矿机械制造股份有限公司山西太原030031

矿用刮板输送机的机头传动部上所用闸盘联接套的主要功能是实现减速器与电机之间的联接,该联接部件加工位置不仅有精度和公差要求,而且有60°圆周均布要求。因此,在铣床上加工时必须定位可靠和分度精准。为此,设计了专用的闸盘联接套铣... 详细信息

矿用刮板输送机的机头传动部上所用闸盘联接套的主要功能是实现减速器与电机之间的联接,该联接部件加工位置不仅有精度和公差要求,而且有60°圆周均布要求。因此,在铣床上加工时必须定位可靠和分度精准。为此,设计了专用的闸盘联接套铣用加工工艺装置。该装置定位精准、安全可靠、装卸方便,既能保证被加工工件尺寸、精度、粗糙度要求,又可明显提高加工质量和效率。

关键词：闸盘联接套工艺装置定位可靠分度精准

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斑马鱼视网膜微细结构及发育特征

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解剖学报 2024年第1期55卷 105-112页

作者：冯丽萍徐伊琳陈珣刘大海王军勇王晓瑛林金杏上海实验动物研究中心上海201203 复旦大学附属眼耳鼻喉科医院眼科上海200031 复旦大学上海市卫健委近视眼重点实验室上海200031 上海市眼视光学研究中心上海200031 上海必凯科翼生物科技有限公司上海201203

目的探讨斑马鱼眼球和视网膜的微细结构及不同发育阶段的形态特征,为其作为视觉研究模型奠定基础。方法分别选取不同周龄的8组斑马鱼,每组各6条,共48条。利用光学显微镜和透射电子显微镜观察不同发育阶段的斑马鱼眼球结构,并测量视网膜... 详细信息

目的探讨斑马鱼眼球和视网膜的微细结构及不同发育阶段的形态特征,为其作为视觉研究模型奠定基础。方法分别选取不同周龄的8组斑马鱼,每组各6条,共48条。利用光学显微镜和透射电子显微镜观察不同发育阶段的斑马鱼眼球结构,并测量视网膜各层厚度,分析其时空发育模式。从显微结构及超微结构上观察视网膜中各种细胞形态特征及神经连接方式,尤其是视杆细胞和视锥细胞的结构差异。结果斑马鱼视网膜可分为色素上皮层、视杆视锥层、外界膜、外核层、外网层、内核层、内网层、神经节细胞层、神经纤维层和内界膜等10层。与视锥细胞相比,视杆细胞的细胞核更小且电子密度更高。感光细胞终足整齐地排列在外网层,与水平细胞和双极细胞形成神经连接,并在其内观察到多条突触带。在斑马鱼视网膜中,最早发育的是神经节细胞层和内核层,随着斑马鱼的生长发育,视杆视锥层和色素上皮层厚度逐渐增长,10周左右视网膜的结构基本发育完成。结论斑马鱼视网膜形态结构典型,分层明显,神经细胞高度分化,外网层神经连接丰富。斑马鱼眼球发育特征与大多数哺乳动物相似。

关键词：视网膜视杆细胞视锥细胞透射电子显微镜斑马鱼

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XGN-40.5 kV气体绝缘金属封闭开关设备抗震性能研究

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电工电气 2024年第4期 65-71页

作者：骆钰鑫黄鑫郝留成姜云风张智慧刘子健平高集团有限公司河南平顶山467000

轨道交通供电系统在山地尤其高海拔地区建设条件相对恶劣,对供电系统设备的抗震性能的要求也不断提升。以XGN-40.5 kV气体绝缘金属封闭开关设备(GIS)为研究对象,采用有限元分析软件,建立三维有限元计算模型,在自重载荷条件下对其进行静... 详细信息

轨道交通供电系统在山地尤其高海拔地区建设条件相对恶劣,对供电系统设备的抗震性能的要求也不断提升。以XGN-40.5 kV气体绝缘金属封闭开关设备(GIS)为研究对象,采用有限元分析软件,建立三维有限元计算模型,在自重载荷条件下对其进行静力分析、模态分析和地震作用下的反应谱分析。计算结果表明:该GIS开关设备具有较好的抗震性能,在0.5g地震激励下的抗震性能满足规范要求。

关键词：轨道交通气体绝缘金属封闭开关设备抗震性能静力分析模态分析反应谱分析

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中药调控RhoA信号通路防治糖尿病肾病研究进展

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中医学报 2024年第3期39卷 547-554页

作者：陈影刘玲玉刘浩飞冯睿苗少博马继伟河南中医药大学第一临床医学院河南郑州450000 河南中医药大学第一附属医院肾病科二病区河南郑州450000

RhoA信号通路在糖尿病肾病的发生发展中发挥着关键作用,可作为糖尿病肾病的治疗靶点。中药活性成分及中药复方可通过调控RhoA信号通路发挥抗氧化应激、抑制炎症反应、抗纤维化、维持内皮细胞功能、保护足细胞等作用,延缓糖尿病肾病的进... 详细信息

RhoA信号通路在糖尿病肾病的发生发展中发挥着关键作用,可作为糖尿病肾病的治疗靶点。中药活性成分及中药复方可通过调控RhoA信号通路发挥抗氧化应激、抑制炎症反应、抗纤维化、维持内皮细胞功能、保护足细胞等作用,延缓糖尿病肾病的进展,具有多组分、多靶点、副作用小等优势。目前,中药调控RhoA信号通路防治糖尿病肾病的研究仍存在不足之处:RhoA在糖尿病肾病中作用机制复杂,尚未明确是单一靶点还是多靶点调控RhoA;RhoA信号通路的激活是通过调节多个下游效应蛋白实现的,但目前对下游通路的研究多集中于ROCK,需加强对其他通路的研究;对RhoA通路和糖尿病肾病的关系研究匮乏,多集中于炎症反应的研究,可进一步明确二者关系,拓展炎症反应方向的研究,明确中药单体及复方的作用机制,为相关实验提供理论支撑。

关键词：糖尿病肾病糖尿病 RhoA信号通路氧化应激炎症反应肾脏纤维化内皮功能障碍足细胞损伤

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Epidemiology and Genotypic Diversity of Eurasian Avian-Like H1N1 Swine Influenza Viruses in China

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Virologica Sinica 2021年第1期36卷 43-51页

作者： Zhaomin feng Wenfei Zhu Lei yang Jia liu Lijuan Zhou Dayan Wang Yuelong Shu National Institute for Viral Disease Control and Prevention Collaboration Innovation Center for Diagnosis and Treatment of Infectious DiseasesChinese Center for Disease Control and PreventionKey Laboratory for Medical VirologyNational Health and Family Planning CommissionBeijing 102206China School of Public Health(Shenzhen) Sun Yat-sen UniversityGuangzhou 510275China

Eurasian avian-like H1 N1(EA H1 N1)swine influenza virus(SIV)outside European countries was first detected in Hong Kong Special Administrative Region(Hong Kong,SAR)of China in 2001.Afterwards,EA H1 N1 SIVs have become predominant in pig population in this country.However,the epidemiology and genotypic diversity of EA H1 N1 SIVs in China are still unknown.Here,we collected the EA H1 N1 SIVs sequences from China between 2001 and 2018 and analyzed the epidemic and phylogenic features,and key molecular markers of these EA H1 N1 SIVs.Our results showed that EA H1 N1 SIVs distributed in nineteen provinces/municipalities of China.After a long-time evolution and transmission,EA H1 N1 SIVs were continuously reassorted with other co-circulated influenza viruses,including 2009 pandemic H1 N1(A(H1 N1)pdm09),and triple reassortment H1 N2(TR H1 N2)influenza viruses,generated 11 genotypes.Genotype 3 and 5,both of which were the reassortments among EA H1 N1,A(H1 N1)pdm09 and TR H1 N2 viruses with different origins of M genes,have become predominant in pig population.Furthermore,key molecular signatures were identified in EA H1 N1 SIVs.Our study has drawn a genotypic diversity image of EA H1 N1 viruses,and could help to evaluate the potential risk of EA H1 N1 for pandemic preparedness and response.

关键词： Eurasian avian-like H1N1(EA H1N1)swine influenza viruses(SIV) Epidemiology Genotypes Molecular markers

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Simulation of Horizontal-Two-Dimension Focused Waves Using A Two-Layer Boussinesq-Type Model

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China Ocean Engineering 2023年第5期37卷 725-737页

作者： ZOU Wen-feng WANG Ping liu Zhong-bo FANG Ke-zhao SUN Jia-wen ZHANG Ning-chuan Key Laboratory of coastal and offshore engineering Dalian University of TechnologyDalian 116024China State Environmental Protection Key Laboratory of Marine Ecosystem Restoration National Marine Environmental Monitoring CenterDalian 116023China Dalian Maritime University College of Transportation EngineeringDalian 116024China

Accurate simulation of the horizontal-two-dimension(H2D)focused wave group in deep water requires high accuracy of a numerical model.The two-layer Boussinesq-type model(liu and Fang,2016;liu et al.,2018)with the highest spatial derivative of 2 has high accuracy in both linear and nonlinear properties.Based on the further development of the velocity equations(liu et al.,2023),the H2D numerical model for water waves is established with the prediction-correction-iteration model in the finite difference method,and a composite fourth-order Adams-Bashforth-Moulton scheme is used for time integration.The wave generation method proposed by Hsiao et al.(2005)is applied and calibrated in this H2D model.The numerical calculations lead to the following three main conclusions:First,compared with the analytical solution of Stokes linear waves,the calculated velocity profiles show higher accuracy by using the improved velocity formulas.Second,the simulations of the focused multidirectional wave group are carried out,and good agreements are found,demonstrating that the present H2D numerical model shows high accuracy in simulating focused multidirectional wave groups,and the effectiveness of the improved velocity formulas is also validated.Furthermore,the velocity profiles throughout the computational domain at the time of maximum wave crest are given.Finally,the FFT method is used to obtain the amplitude with different frequencies for several locations,and the changes of the wavelet energy spectrum at different locations are presented for several cases.

关键词： focused wave horizontal-two-dimension model finite difference method nonlinear property

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