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research progress on rolling superlubricity in solid lubricants

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Science China(Technological Sciences) 2024年第7期67卷 1980-1990页

作者： LI PanPan LI HongXuan ZHU DongXiang ZHU YongQi KANG FuYan WANG Wan ZHANG YaXin LIU XiaoHong JI Li ZHOU HuiDi CHEN JianMin State Key laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Chemical Engineering Northwest Minzu UniversityLanzhou 730030China

Superlubricity is an ideal lubrication state where friction nearly vanishes between contact interfaces. It has become one of the most important research topics and approaches owing to its significance in reducing energy consumption and preventing device failures. As an efficient and universal lubricating principle capable of achieving superlubricity, rolling lubrication has attracted widespread attention in recent years. In this review, the theoretical concept of rolling lubrication and the experimental research progress of spherical/scroll structures are summarized. The review focuses on the possibility of achieving rolling lubrication using spherical/scroll structures(such as spherical fullerenes, carbon nanotubes, and formed and constructed spherical/scroll structures). The challenges in achieving rolling lubrication are summarized, and the possibility of molecular rolling lubrication,as well as its potential applications in superlubrication, are discussed.

关键词： spherical/scroll structure rolling lubrication superlubricity fullerene

Strong and ductile Mg alloys developed by dislocation engineering

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Journal of Materials Science & Technology 2019年第3期35卷 394-395页

作者： M.Wang B.B.He M.X.Huang Department of Mechanical Engineering The University of Hong Kong Shenzhen Institute of research and innovation The University of Hong Kong

Dislocation engineering concept has been successfully employed to tackle the strength-ductility trade-off in steels, resulting in the development of high-strength high-ductility deformed and partitioned(D&P)steel. The present perspective proposes to employ such dislocation engineering concept to develop strong and ductile magnesium(Mg) alloys. High density of dislocations could be generated at appropriate temperature and retained in the Mg alloy after quenching to room temperature. Those dislocations inherited from the warm deformation could provide dislocation sources when the Mg alloy is deformed at room temperature, resulting in good ductility. The high dislocation density generated at warm deformation provides dislocation forest hardening, leading to improved yield strength of Mg alloy.

关键词： Dislocation engineering Mg alloys Warm rolling Strength and ductility

Remote Sensing Monitoring of Surface Characteristics in the Badain Jaran, Tengger, and Ulan Buh Deserts of China

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Chinese Geographical Science 2019年第1期29卷 151-165页

作者： LIU Qingsheng LIU Gaohuan HUANG Chong LI He State Key laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Jiangsu Center for Collaborative innovation in Geographical Information Resource Development and Application

Deserts and sandy land in northern China are very susceptible to sandy desertification and are the main source of sand-dust storms of Asian dust. However, because of the complex factors involved, descriptions of the relationship between sandy desertification and surface characteristics in these regions are lacking. We monitored the surface characteristics and their changes in time using information about soil, vegetation, and landforms in the Badain Jaran Desert(BJD), Tengger Desert(TD), and Ulan Buh Desert(UBD) in the northern China. The monitoring was done using tasseled cap angle(TCA), disturbance index(DI), and topsoil grain size index(TGSI) from Moderate Resolution Imaging Spectroradiometer(MODIS) images combined with a decision tree classification. Results showed that the TD had higher topsoil fine sand content, and the ratio of non-vegetated to vegetated areas was similar with that in the UBD. Northeast-southwest coarse sand dunes with thin interdune(NECTI) dominated the BD, fine sand dunes(FSD) dominated the TD, and a combination of northeast-southwest coarse sand dunes with wide interdune(NECWI) and northwest-southeast coarse sand dunes with wide interdune(NWCWI) dominated the UBD. From 2000 to 2015, in the BJD the area of the NECTI, non-sand dune(Non) and potential sand sources(PSS) increased, whereas the area of the NECWI, FSD and NWCWI decreased, indicating a improve process in the BJD. In the TD, the area covered by Non increased, whereas the area covered by PSS, NECWI, NECTI, FSD, and NWCWI decreased from 2000 to 2015. The area covered by the various surface characteristic types fluctuated annually in the UBD from 2000 to 2015. Changes in surface characteristics reflect the combined effects of natural conditions and human activity. The findings of our study will assist scientists and policy makers in proposing different management techniques to combat sandy desertification for the different surface characteristics of these regions.

关键词： surface characteristics MODIS desert tasseled cap angle disturbance index topsoil grain size index

Transient self-assembly driven by chemical fuels

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ChemPhysMater 2024年第1期3卷 1-23页

作者： Ling Wang Jin Yuan Jingcheng Hao Key laboratory of Colloid and Interface Chemistry Shandong UniversityMinistry of EducationJinan 250100China School of Chemistry and Chemical Engineering Qilu Normal UniversityJinan 250200China

Self-assembly has been extensively studied in chemistry,physics,biology,and materials engineering and has become an important“bottom-up”approach in creating intriguing structures for different *** dissipative self-assembly to construct fuel-dependent,energy-consuming,and dynamic nonequilibrium systems is important for developing intelligent life-like ***,dissipative self-assembly has become a research hotspot in materials chemistry,biomedical science,environmental chemistry,and physical *** in-depth understanding of the process and mechanism provides useful insights to the researchers for devel-oping materials using dissipative self-assembly and also helps guide future innovation in material *** critical review comprehensively analyzes various chemical fuel input and energy consumption mechanisms,supported by numerous illustrative *** transient assemblies,including gels,vesicles,micelles,and nanoparticle aggregates,have been systematically studied in our and other *** relationship between the molecular structure of precursors and temporal assemblies in dissipative self-assemblies is discussed from the perspective of physical *** dissipative self-assembly methods to construct functional assemblies provides important implications for constructing high-energy,nonequilibrium,and intelligent functional materials.

关键词： Self-Assembly Chemical Fuel Consumption mechanisms Functional assemblies

High Quality Audio Object Coding Framework Based on Non-Negative Matrix Factorization

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China Communications 2017年第9期14卷 32-41页

作者： Tingzhao Wu Ruimin Hu Xiaochen Wang Shanfa Ke Jinshan Wang National Engineering research Center for Multimedia Software School of Computer ScienceWuhan University Hubei Key laboratory of Multimedia and Network Communication Engineering Wuhan University Collaborative innovation Center of Geospatial Technology

Object-based audio coding is the main technique of audio scene coding. It can effectively reconstruct each object trajectory, besides provide sufficient flexibility for personalized audio scene reconstruction. So more and more attentions have been paid to the object-based audio coding. However, existing object-based techniques have poor sound quality because of low parameter frequency domain resolution. In order to achieve high quality audio object coding, we propose a new coding framework with introducing the non-negative matrix factorization(NMF) method. We extract object parameters with high resolution to improve sound quality, and apply NMF method to parameter coding to reduce the high bitrate caused by high resolution. And the experimental results have shown that the proposed framework can improve the coding quality by 25%, so it can provide a better solution to encode audio scene in a more flexible and higher quality way.

关键词： object-based audio coding non-negative matrix factorization audio scenecoding

Paving the road toward the use of β-Fe2O3 in solar water splitting: Raman identification, phase transformation and strategies for phase stabilization

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National Science Review 2020年第6期7卷 1059-1067页

作者： Ningsi Zhang Xin Wang Jianyong Feng Huiting Huang Yongsheng Guo Zhaosheng Li Zhigang Zou Collaborative innovation Center of Advanced Microstructures National Laboratory of Solid State Microstructures College of Engineering and Applied Sciences Nanjing University Jiangsu Key laboratory of Nano Technology Nanjing University

Although β-Fe2O3has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap, the study of β-Fe2O3photoanodes for water splitting is elusive as a result of their metastable nature. Raman identification of β-Fe2O3is theoretically and experimentally investigated in this study for the first time, thus clarifying the debate about its Raman spectrum in the literature. Phase transformation of β-Fe2O3toα-Fe2O3was found to potentially take place under laser and electron irradiation as well as ***, phase transformation of β-Fe2O3to α-Fe2O3was inhibited by introduction of Zr doping, andβ-Fe2O3was found to withstand a higher annealing temperature without any phase transformation. The solar water splitting photocurrent of the Zr-doped β-Fe2O3photoanode was increased by 500% compared to that of the pure β-Fe2O3photoanode. Additionally, Zr-doped β-Fe2O3exhibited very good stability during the process of solar water splitting. These results indicate that by improving its thermal stability,metastable β-Fe2O3film is a promising photoanode for solar water splitting.

关键词： solar energy conversion metastable phase phase transformation iron oxide photoelectrochemical water splitting

An updated review and conceptual model for optimizing WEEE management in China from a life cycle perspective

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Frontiers of Environmental Science & Engineering 2017年第5期11卷 21-32页

作者： Xiaolong Song Jingwei Wang Jianxin Yang Bin Lu WEEE research Center of Shanghai Polytechnic University Shanghai 201209 China Shanghai Collaborative innovation Center for WEEE Recycling Shanghai 201209 China State Key laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Waste electrical and electronic equipment （WEEE） is a rapidly growing category of solid waste. China is now facing WEEE problems from both growing domestic generation and illegal imports. Currently, the amount of WEEE formally treated has increased steadily in China. The layout of the formal sector has been basically completed. Meanwhile, by controlling illegal disassembly activities, the informal sector has been gradually transformed to formal one. Beginning with the overview of the WEEE recycling industry in China, this paper first lists the latest progress in WEEE management from such aspects as the new edition of China RollS Directive （Restriction of Hazardous Substances Directive）, the updated WEEE Treatment List, the updated WEEE fund standard, the revised National Hazardous Waste List, and a brand-new plan on extended producer responsibility. In so doing, we elucidate the current challenges on WEEE management in detail： the imbalance between fund levies and subsidies, the gap in the supervision scope, the homogenization of recycling industry and the lack of life cycle approaches. Finally, a conceptual framework for integrated management of WEEE is proposed from a life cycle perspective. Overall, the life cycle management of WEEE includes three aspects： developing life cycle information for decision-making, implementing life cycle engineering with life cycle tools, and improving WEEE legislation based on life cycle thinking. By providing specific operating strategies, this life cycle framework should help to optimize WEEE management in developing countries where legislation is imperfect and the recycling system is relatively immature.

关键词： Waste electrical and electronic equipment E-wasteLife cycle management China

Fracture mode identification of low alloy steels and cast irons by electron back-scattered diffraction misorientation analysis

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Journal of Materials Science & Technology 2017年第12期33卷 1582-1595页

作者： Shao-Shi Rui Yi-Bo Shang Wenhui Qiu Li-Sha Niu Hui-Ji Shi Shunsaku Matsumoto Yasuharu Chuman Applied Mechanics laboratory School of Aerospace EngineeringTsinghua UniversityBeijing 100084China Residential Air Conditioning Division MIDEAFoshan528311China Strength research Department Research&Innovation CenterMitsubishi Heavy IndustriesLtd.Nagasaki 851-0392Japan

The fracture modes of low alloy steels and cast irons under tensile and fatigue conditions were identified by electron back-scattered diffraction（EBSD） misorientation analysis in this research. The curves of grain reference orientation deviation（GROD） distribution perpendicular to the fracture surface were obtained by EBSD observation, and the characteristics of each fracture mode were identified. The GROD value of the specimen fractured in tension decreases to a constant related to the elongation of corresponding specimen in the far field（farther than 5 mm away from the fracture surface）. The peak exhibits in GROD curves of two smooth specimens and a notched specimen near the fracture surface（within 5 mm away from the fracture surface）, and the formation mechanisms were discussed in detail based on the influences of specimen geometries（smooth or notched） and material toughness. The GROD value of fatigue fractured specimen is close to that at undeformed condition in the whole field, except the small area near the crack path. The loading conditions（constant stress amplitude loading or constant stress intensity factor range K loading） and the EBSD striation formation during fatigue crack propagation were also studied by EBSD observation parallel to the crack path.

关键词： Fracture mode identification Low alloy steels Cast irons Electron back-scattered diffraction (EBSD) Misorientation

Rab27a/Slp2-a complex is involved in Schwann cell myelination

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Neural Regeneration research 2016年第11期11卷 1830-1838页

作者： Wen-feng Su Yun Gu Zhong-ya Wei Yun-tian Shen Zi-han Jin Ying Yuan Xiao-song Gu Gang Chen Jiangsu Key laboratory of Neuroregeneration Co-innovation Center of NeuroregenerationNantong University Affiliated Hospital of Nantong University

Myelination of Schwann cells in the peripheral nervous system is an intricate process involving myelin protein trafficking. Recently, the role and mechanism of the endosomal/lysosomal system in myelin formation were emphasized. Our previous results demonstrated that a small GTPase Rab27a regulates lysosomal exocytosis and myelin protein trafficking in Schwann cells. In this present study, we established a dorsal root ganglion （DRG） neuron and Schwann cell co-culture model to identify the signals associated with Rab27a during myelination. First, Slp2-a, as the Rab27a effector, was endogenously expressed in Schwann cells. Second, Rab27a expression significantly increased during Schwann cell myelination. Finally, Rab27a and Slp2-a silencing in Schwann cells not only reduced myelin protein expression, but also impaired formation of myelin-like membranes in DRG neuron and Schwann cell co-cultures. Our findings suggest that the Rab27a/ Slp2-a complex affects Schwann cell myelination in vitro.

关键词： nerve regeneration Schwann cells dorsal root ganglion neurons co-culture myelin proteins myelination Rab27 effectors Rab27a Slp2-a neural regeneration