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Ultralight aerogel sphere composed of nanocellulose-derived carbon nanofiber and graphene for excellent electromagnetic wave absorption

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Nano Research 2023年第5期16卷 7931-7940页

作者： Runa Zhang Bin Li yunfei yang Na Wu Zhuyin Sui Qingfu Ban Lili Wu Wei Liu Jiurong Liu Zhihui Zeng Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials Ministry of EducationSchool of Materials Science and EngineeringShandong UniversityJinan 250061China Department of Chemistry and Applied Biosciences ETH ZurichZurich CH-8093Switzerland School of Chemistry and Chemical Engineering Yantai UniversityYantai 264005China State Key Laboratory of Crystal Materials Institute of Crystal MaterialsShandong UniversityJinan 250100China Shenzhen Research Institute of Shandong University Shenzhen 518063China Suzhou Research Institute of Shandong University Suzhou 215123China

A novel type of three-dimensional ultralight aerogel sphere,consisting of one-dimensional nanocellulose-derived carbon fibers and two-dimensional graphene layers,was prepared based on a developed drop-freeze-drying followed by carbonization *** nanofibrous carbon efficiently prevents the agglomeration of the graphene layers,which,in turn,reduces the shrinkage and maintains the structural stability of the hybrid carbon aerogel ***,the aerogel spheres showing an ultralow-density of 2.8 mg/cm^(3) and a porosity of 99.98%accomplish the tunable dielectric property and electromagnetic wave(EMW)absorption *** high-efficiency utilization of biomass-derived fibrous nanocarbon,graphene,the porous structure of the hybrid aerogel spheres leads to the excellent EMW absorption *** aerogel spheres display an effective absorption bandwidth of 6.16 GHz and a minimum reflection loss of−70.44 dB even at a filler loading of merely 3 wt.%,significantly outperforming that of other biomass-derived carbon-based EMW absorbing *** work offers a feasible,facile,scalable approach for fabricating high-performance and sustainable biomass-based aerogels,suggesting a tremendous application potential in EMW absorption and aerospace.

关键词： nanocellulose aerogel graphene electromagnetic wave absorption composite

Metal sulfides based composites as promising efficient microwave absorption materials:A review

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Journal of Materials Science & Technology 2022年第9期104卷 244-268页

作者： Bin Li Fenglong Wang Kejun Wang Jing Qiao Dongmei Xu yunfei yang Xue Zhang Longfei Lyu Wei Liu Jiurong Liu School of Materials Science and Engineering Shandong UniversityJinan 250061China 96901 Troops of the People’s Liberation Army Beijing 100085China State Key Laboratory of Crystal Materials Institute of Crystal MaterialsShandong UniversityJinan 250100China

The increasingly severe electromagnetic microwave pollution raises higher requirements for the development of efficient microwave absorption(MA)*** sulfides are regarded as potential robust MA materials because of their unique optical,thermal,electrical,and magnetic properties,as well as the controllable ***,due to the limited MA performances of unary metal sulfides,morphology regulations and foreign materials hybridizations are adopted as effective strategies to improve their MA *** years witnessed the fast research progresses on the metal sulfides based MA materials and thus,a systematic literature survey on the materials design,fabrication,characterizations,MA behaviors,and the mechanisms behind is,highly desirable to summarize the rapid progress of this hot research area so as to provide guidance for the future development *** review firstly reviewed the research background,research progress,and basic principles of MA ***,the present synthetic methods and performance improvement strategies of metal sulfides based MA materials are systematically ***,by comparing the MA properties of one-dimensional,two-dimensional,and three-dimensional metal sulfides based composites,the influence of dimensionality and morphology on the MA properties are *** summarizing the research process of metal sulfides/dielectrics composites,metal sulfides/magnets composites,and metal sulfides/dielectrics/magnets composites MA materials,the influence of foreign materials hybridizations on the loss mechanisms and impedance matching conditions of metal sulfides based composites are ***,the challenges and development prospects of metal sulfides based MA materials are *** review would provide a comprehensive understanding and insightful guidance for the exploration and development of efficient MA materials with thin thickness,light weight,wide absorption bandwidth,and strong abs

关键词： Metal sulfides Microwave absorption Structure regulation Materials hybridization Impedance matching

Non‑Magnetic Bimetallic MOF‑Derived Porous Carbon‑Wrapped TiO2/ ZrTiO4 Composites for Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2021年第5期13卷 45-60页

作者： Jing Qiao Xue Zhang Chang Liu Longfei Lyu yunfei yang Zhou Wang Lili Wu Wei Liu Fenglong Wang Jiurong Liu School of Materials Science and Engineering Shandong UniversityJinan 250061People’s Republic of China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100People’s Republic of China

Modern communication technologies put forward higher requirements for electromagnetic wave(EMW)absorption ***-organic framework(MOF)derivatives have been widely concerned with its diverse *** break the mindset of magneticderivative design,and make up the shortage of monometallic non-magnetic derivatives,we first try non-magnetic bimetallic MOFs derivatives to achieve efficient EMW *** porous carbon-wrapped TiO2/ZrTiO4 composites derived from PCN-415(TiZr-MOFs)are qualified with a minimum reflection loss of−67.8 dB(2.16 mm,13.0 GHz),and a maximum effective absorption bandwidth of 5.9 GHz(2.70 mm).Through in-depth discussions,the synergy of enhanced interfacial polarization and other attenuation mechanisms in the composites is ***,this work confirms the huge potentials of nonmagnetic bimetallic MOFs derivatives in EMW absorption applications.

关键词： Bimetallic metal-organic framework PCN-415 MOF derivatives TiO2/ZrTiO4/C composites Electromagnetic wave absorption

Thermal and textural properties of extruded rice affect its cooking performances and the texture of the steamed extruded rice

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Grain & Oil Science and Technology 2024年第4期7卷 237-245页

作者： Yulong Wang Lingjie Jiang Kangru Cui Zhonghua Gu yunfei yang Renyong Zhao Xinwei Wang Hongxin Jiang College of Food Science and Technology Henan University of TechnologyZhengzhouHenan 450001China Food Laboratory of Zhongyuan LuoheHenan 462300China

Extruded rice has increasingly gained popularity in the market due to its convenience and acceptable *** objective of this study was to understand how the physicochemical,thermal,and textural properties of the extruded rice affected its cooking properties and texture of the cooked *** was found that air trapped in the grains during extrusion reduced the transparency of extruded *** air trapped in the grains reduced the true density of the extruded rice,which in turn decreased the hardness of extruded rice.A looser internal structure of extruded rice grain,as indicated by the lower true density,resulted in a faster hydration and shorter optimum cooking *** rices showed two thermal-transition peaks,with peak 1 from 93.3℃ to 112.8℃ and peak 2 from 107.5℃ to 132.5℃.The increased hardness of extruded rice led to increases in its thermaltransition temperatures,longer optimum steaming time,and decreases in its water absorption and cooking loss,which resulted in an increase in the hardness and a reduction in the adhesiveness of the steamed *** study provides insights into the key factors determining the eating quality of extruded rice,which is beneficial for food scientists in developing premium extruded rice.

关键词： Extruded rice Textural properties Cooking properties Thermal properties Pasting properties

A Comparative Study of General Education Between China’s and Singapore’s Universities

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Journal of Contemporary Educational Research 2020年第10期4卷 76-79页

作者： yunfei yang University of Electronic Science and Technology of China Shijiazhuang 611731Hebei ProvinceChina

Along with the development of knowledgebased economy,interdisciplinary talents have received widespread *** teaching students professional knowledge,universities also focus on general *** studying the education objectives and curriculum of China and Singapore,this paper makes a comparative analysis of the similarities and differences between UESTC and NTU in terms of general education objectives and curriculum design,so as to provide certain references for universities,especially science and engineering universities,and to further improve general education.

关键词： General education Education Objective Curriculum System

微型风力发电机组无数字控制MPPT充电器研究

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太阳能学报 2015年第9期36卷 2307-2313页

作者：杨云飞常熟理工学院电气与自动化工程学院常熟215500 南京航空航天大学自动化学院南京210016

对常用微型风力发电机组结构存在的缺点以及缺乏功率优化控制的现状,提出一种新型的机组结构,实现对机组输出功率的优化控制、对蓄电池充放电周期的优化管理以及对机组在高风速区运行时转速的限制。为了解决常规的最大功率跟踪控制策略... 详细信息

对常用微型风力发电机组结构存在的缺点以及缺乏功率优化控制的现状,提出一种新型的机组结构,实现对机组输出功率的优化控制、对蓄电池充放电周期的优化管理以及对机组在高风速区运行时转速的限制。为了解决常规的最大功率跟踪控制策略因采用数字控制器带来控制成本高的问题,通过合理优化变换器的主电路参数和运行状态实现机组在不同风速下的最大功率跟踪运行,可明显降低微型风力发电机组的控制。通过1.2 k W实验验证理论分析的正确性及所提控制策略的有效性。

关键词：风力发电微型机组最大功率跟踪无数字控制

Iron-doped Ag/Ni_(2)(CO_(3))(OH)_(2)hierarchical microtubes for highly efficient water oxidation

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Carbon Energy 2022年第5期4卷 939-949页

作者： Huiwen Zhang Shuxuan Liu Enlai Hu yunfei yang Huimin Zhang Yuting Zhu Lijing Yan Xuehui Gao Jing Zhang Zhan Lin Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of ChemistryZhejiang Normal UniversityJinhuaChina College of Materials and Chemistry China Jiliang UniversityHangzhouChina Guangzhou Key Laboratory of Clean Transportation Energy Chemistry Guangzhou Higher Education Mega CenterGuangdong University of TechnologyGuangzhouGuangdongChina

Doping of foreign atoms and construction of unique structures are considered as effective approaches to design high-activity and strongdurability ***,we report Fe-doped nickel hydroxide carbonate hierarchical microtubes with Ag nanoparticles(denoted Ag/NiFeHC HMTs)through hydrolysis precipitation *** tests and density functional theory calculations reveal that Fe doping can tune the electron configuration to enhance the conductivity,markedly improve the electrochemical surface area to expose more active sites,and act as reactive centers to lower the free energy of the rate determination *** addition,the unique hierarchical structure can also offer active sites and excellent cycling *** from these advantages,the as-obtained Ag/NiFeHC HMTs show excellent oxygen evolution reaction activity,with an overpotential of 208 mV at 10 mA cm^(−2)in 1.0M ***,it could achieve long-term stability at a current density of 20 mA cm^(−2)for 24 h.

关键词： density functional theory Fe doping Ni2(CO3)(OH)2 hierarchical microtubes water oxidation reaction

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《蝴蝶梦》的生态女性主义解读

《蝴蝶梦》的生态女性主义解读

作者： yang yunfei 西安外国语大学

学位级别：硕士

达芙妮·杜穆里埃被视为哥特文学的奇才。《蝴蝶梦》是她最成功的一部作品。自1938年面世以来，就引起了国内外读者和评论家对其广泛的关注。传统的对这篇文章的分析多是从悬念、哥特的角度展开的。《蝴蝶梦》的叙事技巧,写作技巧和语... 详细信息

达芙妮·杜穆里埃被视为哥特文学的奇才。《蝴蝶梦》是她最成功的一部作品。自1938年面世以来，就引起了国内外读者和评论家对其广泛的关注。传统的对这篇文章的分析多是从悬念、哥特的角度展开的。《蝴蝶梦》的叙事技巧,写作技巧和语言风格也被很多学者研究过了。除此以外,有些学者也从女性主义,象征主义的角度对这部作品进行了研究。但是，少有学者从生态女性主义的角度对这部作品展开分析和研究。此论文就是在生态女性主义的理论的指导下分析《蝴蝶梦》,其主要是分析男人和女人的关系以及男人对女人的统治和对自然统治内在间的关系。

关键词：生态女性主义《蝴蝶梦》男人女人自然

Leaf Growth of Different Populations of Vetiveria zizanioides

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Animal Husbandry and Feed Science 2014年第6期6卷 304-307,327页

作者： Liu Jinxiang Peng Xuemei yang yunfei Institute of Tropical Pratacultural Sciences Lingnan Normal University Teaching Laboratory Management Center Guizhou Normal College Insitute of Pratacultural Sciences Key Laboratory for Vegetation EcologyMinistry of EducationNortheast Normal University

Large sample sampling was adopted in this paper for the statistical analysis of leaves of four populations of Vetiveria zizanioides （ introduced, local wild, domesticated wild populations of different years）. The results showed that four populations varied in different degrees in terms of tiller height, leaf biomass, and leaf biomass ratio. Leaf length, leaf width, and ratio of leaf width to length of different populations also varied, but had similar power-function change regularity, and showed converging leaf biomass growth pattern and leaf growth process.

关键词： Vetiveria zizanioides Leaf Growth pattern