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Intrinsic superflat bands in general twisted bilayer systems

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Light(Science & Applications) 2022年第7期11卷 1475-1481页

作者： hongfei wang Shaojie Ma Shuang Zhang Dangyuan Lei Department of Materials Science and Engineering City University of Hong KongKowloonHong Kong 999077China Department of Physics University of Hong KongHong Kong 999077China Department of Electrical and Electronic Engineering University of Hong KongHong Kong 999077China

Twisted bilayer systems with discrete magic angles,such as twisted bilayer graphene featuring moirésuperlattices,provide a versatile platform for exploring novel physical ***,we discover a class of superflat bands in general twisted bilayer systems beyond the low-energy physics of magic-angle twisted *** considering continuous lattice dislocation,we obtain intrinsic localized states,which are spectrally isolated at lowest and highest energies and spatially centered around the AA stacked region,governed by the macroscopic effective energy potential *** localized states exhibit negligible inter-cell coupling and support the formation of superflat bands in a wide and continuous parameter space,which can be mimicked using a twisted bilayer nanophotonic *** finding suggests that general twisted bilayer systems can realize continuously tunable superflat bands and the corresponding localized states for various photonic,phononic,and mechanical waves.

关键词： properties. twisted bands

Temperature-sensitive molecularly imprinted microgels with esterase activity

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Science China Chemistry 2011年第3期54卷 515-520页

作者： wang hongfei YANG Hao ZHANG LiMing Key Laboratory for Designed Synthesis and Application of Polymer Materials School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 China Key Laboratory for Polymer Composite and Functional Materials Ministry of EducationSchool of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 China

Temperature-sensitive molecularly imprinted microgels(MIGs)exhibiting esterase activity were prepared by a reverse emulsion method using dialdehyde dextran-histidine conjugate(PAD-His)as the functional macromonomer and p-nitrophenyl phosphate(NPP)as the stable transition state analogue(TSA)as well as Co2+as the coordination *** catalytic activity of MIGs was greatly influenced by the amount of the template,and could be modulated by *** hydrolysis kinetics of p-nitrophenyl acetate(NPA)in the presence of MIGs could be described by the Michaelis-Menten *** MichaelisMenten constant and maximum velocity were found to be 2.2×105mol/L and 2.04×10 -8mol/h,*** addition,the MIGs were found to have a high catalytic selectivity to NPA.

关键词： molecular imprinting microgels esterase temperature sensitivity dextran

Flume experiments to study fine-grain migration and its impact on slope stability

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Journal of Mountain Science 2024年第10期21卷 3552-3566页

作者： wang Baoliang wang Quanwei LI Yong YAO Zhenguo wang hongfei Yellow River Engineering Consulting Co.Ltd. Zhengzhou 450003China Key Laboratory of Water Management and Water Security for Yellow River Basin Ministry of Water Resources(under construction)Zhengzhou 450003China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Key Laboratory of mountain Hazards and Surface Process Chinese Academy of SciencesChengdu 610041China

Fine grains migration is a primary cause of landslides and debris *** study investigates the effect of fine-grain migration on slope failure through flume experiments,focusing on the spatiotemporal characteristics and mechanisms of slope stability.A series of artificial rainfall flume experiments with varying rainfall intensities and slopes were conducted using soil samples collected from Wei Jia *** experiments monitored pore-water pressure,grain migration,and failure ***-size distribution parameters(μand Dc)were analyzed to understand the migration path and accumulation of fine *** experiments reveal that fine-grain migration significantly alters soil structure,leading to random blockage and interconnection of internal pore *** changes result in fluctuating pore-water pressure distributions and uneven fine-grain accumulation,critical factors in slope *** failures occur randomly and intermittently,influenced by fine-grain content in runoff and resulting pore-water pressure *** study highlights that fine-grain migration plays a vital role in slope stability,with significant implications for predicting and mitigating slope *** stochastic nature of fine-grain migration and its impact on soil properties should be incorporated into predictive models to enhance their accuracy and reliability.

关键词： Fine-grain migration Slope stability Pore-water pressure Artificial rainfall Soil structure Flume experiments

Recent advances in the synthesis of non-carbon two-dimensional electrode materials for the aqueous electrolyte-based supercapacitors

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Chinese Chemical Letters 2021年第12期32卷 3733-3752页

作者： hongfei wang Yijun Zhong Jiqiang Ning Yong Hu Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of ChemistryZhejiang Normal UniversityJinhua 321004China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Vacuum Interconnected Nanotech Workstation Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China

Supercapacitors(SCs) with high power density and long cycling span life are demanding energy storage devices that will be an attractive power solution to modern electronic and electrical applications. Numerous theoretical and experimental works have been devoted to exploring various possibilities to increase the functionality and the specific capacitance of electrodes for SCs. Non-carbon two-dimensional(2D)materials have been considered as encouraging electrode candidates for their chemical and physical advantages such as tunable surface chemistry, high electronic conductivity, large mechanical strength, more active sites, and dual non-faradaic and faradaic electrochemical performances. Besides, these 2D materials also play particular roles in constructing highway channels for fast ion diffusion. This concise review summarizes cutting-edge progress of some representative 2D non-carbon materials for the aqueous electrolyte-based SCs, including transition metal oxides(TMOs), transition metal hydroxides(TMHs), transition metal chalcogenides(TMCs), MXenes, metal-organic frameworks(MOFs) and some emerging materials. Different synthetic methods, effective structural designs and corresponding electrochemical performances are reviewed in detail. And we finally present a detailed discussion of the current intractable challenges and technical bottlenecks, and highlight future directions and opportunities for the development of next-generation high-performance energy storage devices.

关键词： Supercapacitors 2D non-carbon materials Aqueous electrolyte High power density Long cycling span life

Correction of integrated multipoles of five IDs in SSRF

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Nuclear Science and Techniques 2010年第5期21卷 257-260页

作者： LU Jie ZHOU Qiaogen wang hongfei ZHANG Wei Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China Graduate University of Chinese Academy of Science Beijing 100049 China

Five of the seven Phase I beamlines of Shanghai Synchrotron Radiation Facility(SSRF) are based on insertion devices(IDs),which include two wigglers,one elliptically polarized undulator(EPU),and two in-vacuum *** were some inevitable field integral errors in manufacturing the IDs,and these would affect performance of the storage *** integrated multipoles were corrected by using the magic fingers *** this paper,we report the correction method based on the simulated-annealing *** results show that the integrated multipole components were corrected to meet the design specifications.

关键词：上海同步辐射装置集成组件多极光源校正标识模拟退火算法椭圆极化

DARPA Robotics Grand Challenge Participation and Ski-Type Gait for Rough-Terrain Walking

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Engineering 2015年第1期1卷 36-45页

作者： hongfei wang Shimeng Li Yuan F.Zheng Department of Electrical and Computer Engineering Ohio State University

In this paper, we briefly introduce the history of the Defense Advanced Research Projects Agency(DARPA) Grand Challenge programs with particular focus on the 2012 Robotics Challenge. As members of team DRC-HUBO, we propose different approaches for the Rough-Terrain task, such as enlarged foot pedals and a transformation into quadruped walking. We also introduce a new gait for humanoid robot locomotion to improve stability performance, called the Ski-Type gait. We analyze the stability performance of this gait and use the stability margin to choose between two candidate step sequences, Crawl-1 and Crawl-2. Next, we perform a force/torque analysis for the redundant closedchain system in the Ski-Type gait, and determine the joint torques by minimizing the total energy consumption. Based on the stability and force/torque analysis, we design a cane length to support a feasible and stable Crawl-2 gait on the HUBO2 humanoid robot platform. Finally, we compare our experimental results with biped walking to validate the SkiType gait. We also present our team performance in the trials of the Robotics Challenge.

关键词： humanoid robot DARPA robotics challenge(DRC) rough-terrain walking Ski-Type gait

Distinct structural characteristics define a new subfamily of Mycoplasma ferritin

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Chinese Chemical Letters 2022年第11期33卷 4952-4955页

作者： Wenming wang Xiaojia Liu Yajie wang Yuan wang Dan Fu Hongfang Xi Yi Zhao hongfei wang Institute of Molecular Science Shanxi UniversityTaiyuan 030006China State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy Nankai UniversityTianjin 300350China Shanxi Key Laboratory of Pharmaceutical Biotechnology Taiyuan 030006China

Ferritins can generally be divided into four subfamilies based on their structural characteristics,namely,the classic ferritins(Ftns),bacterioferritins(Bfrs),DNA-binding proteins from starved cells(Dps’),and encapsulated ferritins(Enc Ftns).However,the ferritin from Mycoplasma penetrans(Mpef)possesses a particular ferroxidase center with an extreme low activity and exhibits unusual characteristics,indicating that it could be a member of a quite different subfamily of ***,the crystal structure of the ferritin from Ureaplasma urealyticum(Uurf)is presented,Mpef and Uurf have very similar properties,though they display very low sequence ***,ferritins from Mycoplasma with these unique properties do not belong to any known subfamily,but they should rather be placed in a novel ferritin subfamily,which we term Mycoplasma Ferritin(Mfr).

关键词： Ferritin Ferritin subfamily Ureaplasma Mycoplasma Crystal structure

Electrochemical exfoliation for few-layer graphene in molybdate aqueous solution and its application for fast electrothermal film

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Progress in Natural Science:Materials International 2020年第3期30卷 312-320页

作者： Juan Wu hongfei wang Jun Qiu Jingwen Shao Kefu Zhang Lifeng Yan CAS Key Laboratory of Soft Matter Chemistry Hefei National Laboratory for Physical Sciences at the Microscale And Department of Chemical Physics University of Science and Technology of China

There are still serious barriers from laboratory exploration to large-scale production of commercializing highquality graphene, especially by environmental-friendly methods. In this study, a simple and efficient electrochemical method for the preparation of high-quality water-dispersible graphene has been developed using molybdate aqueous solutions as the electrolyte. The exfoliation of graphite paper could be achieved in the electrolyte with a high yield of a few layers graphene（1–5 layers, 76%） and uniform lateral size（1–6 μm, 90%）.The as-obtained few layers graphene well dispersed in aqueous solution with a solubility of ～4 mg mL-1and stability for at least 2 months. It provides a new green method to prepare high-quality graphene. The as-prepared water-dispersible graphene films exhibit significant electrothermal performance, with a steady-state temperature of 147 °C under voltage of 10 V and a maximum heating rate achieved of 11.8 °C s-1.

关键词： Graphene Electrochemical Exfoliation Few-layer Electrothermal film

PpINH1,an invertase inhibitor,interacts with vacuolar invertase PpVIN2 in regulating the chilling tolerance of peach fruit

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Horticulture Research 2020年第1期7卷 591-604页

作者： Xingxing wang Yi Chen Shu Jiang Feng Xu hongfei wang Yingying Wei Xingfeng Shao College of Food and Pharmaceutical Sciences Ningbo University315800 NingboChina

Sucrose metabolism,particularly the decomposition of sucrose by invertase,plays a central role in plant responses to cold *** inhibitors(INHs)evolved in higher plants as essential regulators of sucrose *** limiting invertase activity,INHs keep cellular sugar levels elevated,which provides enhanced protection to plants under *** results showed that the expression of PpVIN2,the only vacuolar invertase(VIN)gene in peach fruit sensitive to chilling temperatures,increases significantly during cold storage,while VIN enzyme activity increases more *** also found that peach fruit transiently overexpressing PpINH1 had decreased VIN *** of PpINH1 and PpVIN2 with recombinant proteins were shown by yeast two-hybrid assays and bimolecular fluorescence complementation assays,as well as in *** cold storage,trehalose-treated peach fruit had significantly increased PpINH1 expression,decreased VIN enzyme activity,and significantly higher sucrose content than did untreated *** a result,the treated fruit had enhanced resistance to chilling ***,our data show that the post-translational repression of VIN enzyme activity by PpINH1 helps maintain sucrose levels in peach fruit during cold storage,thereby improving resistance to chilling injury.

关键词： INH metabolism thereby