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Direct observation of Pt nanocrystal coalescence induced by electron-excitation-enhanced van der Waals interactions

Nano Research 2014年第3期7卷 308-314页

作者： Ying Jiang Yong Wang Yu yang Zhang zhengfei Zhang Wentao Yuan Chenghua Sun Xiao Wei Casey N. Brodsky Chia-Kuang Tsung Jixue Li Xiaofeng Zhang Scott X. Mao Shengbai Zhang Ze Zhang Center of Electron Microscopy and State Key Laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA Centre for Computational Molecular Science Australian Institute for Bioengineering and Nanotechnology University of Queensland St Lucia QLD 4072 Australia Department of Chemistry Boston College Chestnut Hill MA 02467 USA Hitachi High Technologies America Pleasanton CA 94588 USA Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh PA 15261 USA

Nanocrystal coalescence has attracted paramount attention in nanostructure fabrication in the past decades. Tremendous endeavor and progress have been made in understanding its mechanisms, benefiting from the development of transmission electron microscopy. However, many mechanisms still remain unclear, especially for nanocrystals that lack a permanent dipole moment standing on a solid substrate. Here, we report an in situ coalescence of Pt nanocrystals on an amorphous carbon substrate induced by electron-excitation- enhanced van der Waals interactions studied by transmission electron microscopy and first principles calculations. It is found that the electron-beam-induced excitation can significantly enhance the van der Waals interaction between Pt nanocrystals and reduce the binding energy between Pt nanocrystals and the carbon substrate, both of which promote the coalescence. This work extends our understanding of the nanocrystal coalescence observed in a transmission electron microscope and sheds light on a potential pathway toward practical electron- beam-controlled nanofabrication.

关键词： Pt nanocrystals coalescence electron excitation van der Waals interactions

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Optimizing interfacial electronic coupling with metal oxide to activate inert polyaniline for superior electrocatalytic hydrogen generation

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Carbon Energy 2019年第1期1卷 77-84页

作者： Zhen-Feng Huang Jiajia Song Yonghua Du Shuo Dou Libo Sun Wei Chen Kaidi Yuan zhengfei Dai Xin Wang School of Chemical and Biomedical Engineering Nanyang Technological UniversitySingaporeSingapore Singapore-HUJ Alliance for Research and Enterprise NEW-CREATE Phase IICampus for Research Excellence and Technological Enterprise(CREATE)SingaporeSingapore Institute of Chemical and Engineering Sciences A*STARJurong IslandSingapore Department of Chemistry National University of SingaporeSingaporeSingapore School of Materials Science and Engineering Nanyang Technological UniversitySingaporeSingapore

Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient ***,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal *** a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.

关键词： hydrogen evolution interfacial electronic coupling metal oxide N-H bond polyaniline

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Magnetic-field enhanced high-thermoelectric performance in topological Dirac semimetal Cd3As2 crystal

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Science Bulletin 2018年第7期63卷 411-418页

作者： Honghui Wang Xigang Luo Weiwei Chen Naizhou Wang Bin Lei Fanbao Meng Chao Shang Likuan Ma Tao Wu Xi Dai zhengfei Wang Xianhui Chen Hefei National Laboratory for Physical Science at Microscale and Department of Physics University of Science and Technology of China and Key Laboratory of Strongly-coupled Quantum Matter Physics. Chinese Academy of Sciences Hefei 230026 China Physics Department Hong Kong University of Science and Technology Hang Kong China High Magnetic Field Laboratory of the Chinese Academy of Sciences Hefei 230031 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China

Thermoelectric materials can be used to convert heat to electric power through the Seebeck effect. We study magneto-thermoelectric figure of merit （ZT） in three-dimensional Dirac semimetal Cd3A 5 2 crystal. It is found that enhancement of power factor and reduction of thermal conductivity can be realized at the same time through magnetic field although magnetoresistivity is greatly increased. ZT can be highly enhanced from 0.17 to 1.1 by more than six times around 350 K under a perpendicular magnetic field of 7 T. The huge enhancement of ZT by magnetic field arises from the linear Dirac band with large Fermi velocity and the large electric thermal conductivity in CdsA 5 2. Our work paves a new way to greatly enhance the thermoelectric performance in the quantum topological materials.

关键词： Dirac semimetal Thermoelectric material Magnetic field Enhancement of figure of merit

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Flexible coal-derived carbon fibers via electrospinning for self-standing lithium-ion battery anodes

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International Journal of Mining Science and Technology 2024年第12期34卷 1753-1763页

作者： Xing, Baolin Meng, Weibo Liang, Hao Kang, Weiwei Zeng, Huihui Zhang, Chuanxiang Egun, Ishioma Laurene Li, Peng Cao, Yijun Chen, zhengfei Henan International Joint Laboratory of Coal Clean Utilization College of Chemistry and Chemical Engineering Henan Polytechnic University Jiaozuo 454003 China State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization Jiaozuo 454003 China School of Biological and Chemical Engineering NingboTech University Ningbo 315100 China Henan Province Industrial Technology Research Institute of Resources and Materials Zhengzhou University Zhengzhou 450001 China

A series of flexible and self-standing coal-derived carbon fibers (CCFs) were fabricated through electrospinning coupled with carbonization using bituminous coal and polyacrylonitrile (PAN) as the carbon precursors. These CCFs were utilized as free-standing lithium-ion battery (LIB) anodes. Optimizing carbonization temperature reveals that the CCFs exhibit a one-dimensional solid linear structure with a uniform distribution of graphite-like microcrystals. These fibers possess a dense structure and smooth surface, with averaging diameter from approximately 125.0 to 210.0 nm at carbonization temperatures ranging from 600 to 900 °C. During electrospinning and carbonization, the aromatic rings enriched in bituminous coal crosslink with PAN chains, forming a robust three-dimensional (3D) framework. This 3D microstructure significantly enhances the flexibility and tensile strength of CCFs, while increasing the graphite-like sp2 microcrystalline carbon content, thus improving electrical conductivity. The CCFs carbonized at 700 °C demonstrate an optimal balance of sp3 amorphous and sp2 graphite-like carbons. The average diameter of CCFs-700 is 177 nm and the specific surface area (SSA) is 7.2 m2·g−1. Additionally, the fibers contain oxygen-containing functional groups, as well as nitrogen-containing functional groups, including pyridinic nitrogen and pyrrolic nitrogen. Owing to its characteristics, the CCFs-700 showcases remarkable electrochemical performance, delivering a high reversible capacity of 631.4 mAh·g−1. CCFs-700 also exhibit outstanding cycle stability, which retains approximately all of their first capacity (400.1 mAh·g−1) after 120 cycles. This research offers an economical yet scalable approach for producing flexible and self-supporting anodes for LIBs that do not require current collectors, binders and conductive additives, thereby simplifying the electrode fabrication process. © 2024

关键词： Microcrystals

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High-density lipoprotein as a potential carrier for delivery of a lipophilic antitumoral drug into hepatoma cells

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World Journal of Gastroenterology 2005年第7期11卷 954-959页

作者： BinLou Xue-LingLiao Man-PingWu Pei-FangCheng Chun-YanYin zhengfei DepartmentofBiochemistry SchoolofPharmacyFudanUniversityShanghai200032China

AIM: To investigate the possibility of recombinant highdensity lipoprotein (rHDL) being a carrier for delivering antitumoral drug to hepatoma cells. METHODS: Recombinant complex of HDL and aclacinomycin (rHDL-ACM) was prepared by cosonication of apoproteins from HDL (Apo HDL) and ACM as well as phosphatidylcholine. Characteristics of the rHDL-ACM were elucidated by electrophoretic mobility, including the size of particles, morphology and entrapment efficiency. Binding activity of rHDL-ACM to human hepatoma cells was determined by competition assay in the presence of excess native HDL. The cytotoxicity of rHDL-ACM was assessed by MTT method. RESULTS: The density range of rHDL-ACM was 1.063-1.210 g/mL, and the same as that of native HDL. The purity of all rHDL-ACM preparations was more than 92%. Encapsulated efficiencies of rHDL-ACM were more than 90%. rHDL-ACM particles were typical sphere model of lipoproteins and heterogeneous in particle size. The average diameter was 31.26±5.62 nm by measure of 110 rHDL-ACM particles in the range of diameter of lipoproteins. rHDL-ACM could bind on SMMC-7721 cells, and such binding could be competed against in the presence of excess native HDL. rHDL-ACM had same binding capacity as native HDL. The cellular uptake of rHDL-ACM by SMMC-7721 hepatoma cells was significantly higher than that of free ACM at the concentration range of 0.5-10 μg/mL (P<0.01). Cytotoxicity of rHDL-ACM to SMMC-7721 cells was significantly higher than that of free ACM at concentration range of less than 5 ug/mL (P<0.01) and IC50 of rHDL-ACM was lower than IC50 of free ACM (1.68 nmol/L vs3 nmol/L). Compared to L02 hepatocytes, a normal liver cell line, the cellular uptake of rHDL-ACM by SMMC-7721 cells was significantly higher (P<0.01) and in a dose-dependent manner at the concentration range of 0.5-10 μg/*** of the rHDL-ACM to SMMC- 7721 cells was significantly higher than that to L02 cells at concentration range of 1-7.5μg/mL (P<0.01). IC50 for S

关键词： High-density lipoprotein Carrier Antitumoral drug: SMMC-7721 hepatoma cell

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The stability research of coated sodium butyrate

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Feed & Livestock 2011年第1期4卷 40-45页

作者： Guoshun Chen zhengfei Xu Min Zhao Gansu Agricultural University Institute of Animal Science and Technology. National Engineering Laboratory for Biological Feed Security and Contamination Control Biological Coating Engineering PilotPlant Test Base Zhejiang Hangzhou.

The objective of this study is to research the stability of sodium butyrate in feedstuff. The sodium butyrate with three types of coated, common and granule was produced at three differ- ent feed mills and sampled and determined the content. The results showed that the retention rate of common sodium butyrate was 7.35% through carrier difference, mixing, granulating, stomach and digestive tract forepart. The retention rates of granule and coated sodium butyrate （the content of sodium butyrate is 30%） were 17.04% and 72.66% respectively. Therefore, the stability of coated sodium butyrate is obviously higher than common and granule sodium butyrate.

关键词： sodium butyrate coated stability

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高岭土/水合MnO_2复合预涂动态膜的制备

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膜科学与技术 2010年第5期30卷 98-102,112页

作者：杨涛马正飞杨期勇南京工业大学化学化工学院南京210009 九江学院化学化工学院九江332005

为制备出抗污染预涂动态膜,本研究以高岭土和水合MnO2溶胶为涂膜材料,在陶瓷膜管外表面涂制双层复合预涂动态膜,通过对比分析考察该动态膜对乳化油废水的处理效果,并讨论水合MnO2主要制备条件和工艺操作条件对乳化油分离性能的影响,结... 详细信息

为制备出抗污染预涂动态膜,本研究以高岭土和水合MnO2溶胶为涂膜材料,在陶瓷膜管外表面涂制双层复合预涂动态膜,通过对比分析考察该动态膜对乳化油废水的处理效果,并讨论水合MnO2主要制备条件和工艺操作条件对乳化油分离性能的影响,结果表明：制备的复合预涂动态膜具有内层疏松,外层密实的结构,处理乳化油废水表现出极强的分离性能;碱性条件下用0.3 g/L的KMnO4溶液合成水合MnO2可制备出分离性能更佳的复合预涂动态膜;负压抽吸增加跨膜压差、提高搅拌速度以及在285-308 K温度范围内增加温度都可使膜通量增加,但对截留性能的影响不大.

关键词：动态膜预涂水合MnO2 复合

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Lamellar hafnium ditelluride as an ultrasensitive surface-enhanced Raman scattering platform for label-free detection of uric acid

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Photonics Research 2021年第6期9卷 1039-1047页

作者： yang LI HAOLIN CHEN YANXIAN GUO KANGKANG WANG YUE ZHANG PEILIN LAN JINHAO GUO WEN ZHANG HUIQING ZHONG ZHOUYI GUO zhengfei ZHUANG ZHIMING LIU MOE Key Laboratory of Laser Life Science&SATCM Third Grade Laboratory of Chinese Medicine and Photonics Technology College of BiophotonicsSouth China Normal UniversityGuangzhou 510631China Department of Hematology The Seventh Affiliated HospitalSun Yat-sen UniversityShenzhen 518107China Department of Medical Biotechnology School of Basic Medical SciencesGuangzhou University of Chinese MedicineGuangzhou 510006China

The development of two-dimensional(2D)transition metal dichalcogenides has been in a rapid growth phase for the utilization in surface-enhanced Raman scattering(SERS)***,we report a promising 2D transition metal tellurides(TMTs)material,hafnium ditelluride(HfTe2),as an ultrasensitive platform for Raman identification of trace molecules,which demonstrates extraordinary SERS activity in sensitivity,uniformity,and *** highest Raman enhancement factor of 2.32×10^(6)is attained for a rhodamine 6G molecule through the highly efficient charge transfer process at the interface between the HfTe2 layered structure and the adsorbed *** the same time,we provide an effective route for large-scale preparation of SERS substrates in practical applications via a facile stripping *** application of the nanosheets for reliable,rapid,and label-free SERS fingerprint analysis of uric acid molecules,one of the biomarkers associated with gout disease,is performed,which indicates arresting SERS signals with the limits of detection as low as 0.1 mmol/*** study based on this type of 2D SERS substrate not only reveals the feasibility of applying TMTs to SERS analysis,but also paves the way for nanodiagnostics,especially early marker detection.

关键词： stripping applying adsorbed

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Detection of Resistances of Different Corn Varieties to Corn Borer

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Plant Diseases and Pests 2015年第2期6卷 5-8,18页

作者： Huang Kai Miao Yong Shao zhengfei College of Plant Protection Anhui Agricultural University

In order to practice integrated management of corn insect pests effectively, a field experiment was made to study the resistances of 33 corn varieties to corn borer （ Ostrinia furnacalis） in the corn area to the north of the Huaihe River in Anhui Province. The results showed that there were evident differences in resistances of different corn varieties to corn borer and the resistant levels of the same corn variety to corn borer were also different in the whorl stage and the ear stage. In the whorl stage of corn, eight corn varieties, ＇ ‘Zhongnougda 311＇, ‘Zhongke 11＇, ‘ Denghai 3＇, ＇ Dongdan 80＇ , ‘ Liyu 16＇, ‘ Zhengdan 23＇, ‘ Jidan 8＇ and‘ Huayu 13＇ preformed relatively stronger resistance to corn borer. In the ear stage of corn, five corn varieties of ‘ Xundan 20＇, ‘ Qidan 1 ＇, ‘ Zhongke 4＇, ‘ Nongda 108＇ and ＇ Ludan 6018＇ showed relatively stronger resistance to corn borer. The comprehensive resistances of ten corn varieties to corn borer in the whorl stage and the ear stage successively were ‘Zhongnongda 311’ 〉 ‘Zbong, ke 4＇〉 ‘Jidan 8＇〉 ‘ Zhengdan 23＇〉‘Zhengdan 958＇〉 ‘ Qidan 1＇〉 ‘ Zhongdi 985＇〉 ‘Nongda108＇〉 ‘Liyu16＇〉‘Denghai3＇.

关键词： Corn Variety Resistance Corn borer

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Automated apoptosis identification in fluorescence imaging of nucleus based on histogram of oriented gradients of high-frequency wavelet coefficients

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Journal of Innovative Optical Health Sciences 2023年第2期16卷 28-38页

作者： Shutong Liu Limei Su Han Sun Tongsheng Chen Min Hu zhengfei Zhuang MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science College of Biophotonics South China Normal University Guangzhou 510631P.R.China Guangdong Provincial Key Laboratory of Laser Life Science College of Biophotonics South China Normal University Guangzhou 510631P.R.China Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices School of Information and Optoelectronic Science and Engineering South China Normal University Guangzhou 510631 P.R.China SCNU Qingyuan Institute of Science and Technology Innovation Co. Ltd.Qingyuan 511500P.R.China

The automatic and accurate identification of apoptosis facilitates large-scale cell *** identification approaches using nucleus fluorescence imaging are based on specific morphological ***,these parameters cannot completely describe nuclear morphology,thus limiting the identification accuracy of *** paper proposes a new feature extraction method to improve the performance of the model for apoptosis *** proposed method uses a histogram of oriented gradient(HOG)of high-frequency wavelet coefficients to extract internal and edge texture *** HOG vectors are classified using support vector *** experimental results demonstrate that the proposed feature extraction method well performs apoptosis identification,attaining 95:7% accuracy with low cost in terms of *** confirmed that our method has potential applications to cell biology research.

关键词： Apoptosis nucleus fluorescence imaging HOG wavelet decomposition

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