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Relationship between dispersibility of ZrO2 nanoparticles in Ni-ZrO2 electroplated nanocomposite coatings and mechanical properties of nanocomposite coatings

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 186-189页

作者： WANG Wei HOU feng-yan guo He-tong School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

Ni-ZrO2 nanocomposite coatings with monodispersed ZrO2 nanoparticles were prepared from the composite plating bath containing dispersant under DC electrodeposition condition. It is found that the morphology, orientation and hardness of the composite coating with monodispersed ZrO2 nanoparticles have lots of difference from the composite coating with agglomerated ZrO2 nanoparticles and pure nickel coating. Especially, the result of hardness shows that only a very low volume fraction (less than 1%) of monodispered ZrO2 nanoparticles in Ni-ZrO2 composite coatings will result in higher hardness of the coating. The hardness of Ni-ZrO2 nanocomposite coatings with monodispersed and agglomerated ZrO2 nanoparticles are HV 529 and HV 393, respectively. The hardness value of the former composite coatings is over 1.3 times higher than that of the later. All these composite coatings are 2 - 3 times higher than that of pure nickel plating (HV 207) prepared under the same conditions.

关键词： Nanocomposites electroplating coating metal matrix composites Ni-ZrO2

A New Effect of Oxygen Plasma on Two-Dimensional Field-Effect Transistors:Plasma Induced Ion Gating and Synaptic Behavior

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Chinese Physics Letters 2019年第7期36卷 116-120页

作者： Cheng-Lei guo Bin-Bin Wang Wei Xia yan-feng guo Jia-Min Xue Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 School of Physical Science and Technology ShanghaiTech University Shanghai 201210 Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049

Plasma treatment is a powerful tool to tune the properties of two-dimensional materials. Previous studies have utilized various plasma treatments on two-dimensional materials. We find a new effect of plasma treatment. After controlled oxygen-plasma treatment on field-effect transistors based on two-dimensional SnSe2, the capacitive coupling between the silicon back gate and the channel through the 300 nm SiO2 dielectric can be dramatically enhanced by about two orders of magnitude(from 11 n F/cm^2 to 880 nF/cm^2), reaching good efficiency of ionliquid gating. At the same time, plasma treated devices show large hysteresis in the gate sweep demonstrating memory behavior. We reveal that this spontaneous ion gating and hysteresis are achieved with the assistance of a thin layer of water film automatically formed on the sample surface with water molecules from the ambient air, due to the change in hydrophilicity of the plasma treated samples. The water film acts as the ion liquid to couple the back gate and the channel. Thanks to the rich carrier dynamics in plasma-treated two-dimensional transistors, synaptic functions are realized to demonstrate short-and long-term memories in a single device. This work provides a new perspective on the effects of plasma treatment and a facile route for realizing neuromorphic devices.

关键词： Plasma treatment is a powerful two-dimensional materials realizing neuromorphic devices

Long-term Efficacy and Safety of Pamidronate Disodium in Treatment of Bone Metastases in Breast Cancer

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Chinese Journal of Cancer Research 2009年第2期21卷 109-114页

作者： Li-jun Di Jun Ren Ying yan feng-ling Wan guo-gong Song Jing Yu Key Laboratory of Carcinogenesis and Translational Research （Ministry of Education） Peking University School of Oncology Beijing Cancer Hospital ＆ Institute Beijing 100142 China

Objective： To evaluate the long-term efficacy and safety of pamidronate disodium in patients with bone lesions secondary to advanced breast carcinoma. Methods： A retrospective chart review was conducted of 62 patients receiving intravenous pamidronate disodium for metastatic breast cancer. The proportion of patients experiencing at least one skeletal related event （SRE） after 12 months of therapy was determined. Results： The proportion of patients who had an SRE was 29.00% （18 individuals） and the median time to first event was greater than 350 days. Radiotherapy（ll individuals）and pathologic fracture（6 individuals）were the most frequent type of SRE, while cord compression（1 individuals） and hypercalcaemia（0 individuals） were rare. A total of 37 individuals had transient hypocalcaemia without any clinical symptom. No significant creatinine abnormalities were encountered. There were no clinically relevant changes of calcium ,phosphate and creatinine before and after therapy. Conclusion： Long-term treatment with pamidronate disodium significantly reduces and delays skeletal morbidity from osteolytic metastases . Prolonged therapy was well tolerated. This study suggests that the rate of clinically relevant SREs is substantially lower than the event rate observed in phase llI clinical trials.

关键词： Pamidronate disodium Skeletal related event Bone metastases Breast cancer

Nontrivial topological states in the tantalum dipnictides TaX_(2)(X = As, P)

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Tungsten 2020年第3期2卷 251-260页

作者： Xiao‑Lei Liu Hong‑Yuan Wang Hao Su Zhen‑Hai Yu yan‑feng guo School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China CAS Center for Excellence in Superconducting Electronics(CENSE) Chinese Academy of SciencesShanghai 200050China

The intriguing quasiparticles in solids,known as Dirac,Weyl,and Majorana fermions,*** properties akin to those theoretically predicted but never realized in high-energy physics,have excited intensive research activities in recent *** transition metal dipnictides are attractive because of their extremely large magnetoresistance that is usually attributed to the carrier compensation *** briefly review herein the crystal growth,magneto-transport measurements,and theoretical studies of tantalum dipnictides TaAs_(2) and TaP_(2),with the emphasis being put on discussion of the nontrivial topological states in both *** analysis of quantum oscillations of the magnetoresistance unveils nonzero Berry *** chiral negative longitudinal magnetoresistance further points to possible Weyl state,which was recently theoretically sug-gested as the result of the magnetic field-induced Zeeman splitting effect no matter how large the field *** analysis of these intriguing behaviors could brush up our understanding about the family of materials and would be valuable for future work on investigating the magnetic field-induced topological phase transition in such semimetals.

关键词： Tantalum dipnictides Semimetal Crystal growth Nontrivial topological states

Preface to the special issue on topological materials

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Tungsten 2023年第3期5卷 287-287页

作者： yan-feng guo School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

The theoretical prediction and experimental realization of topological phases of matter open a new window for brushing up our knowledge of the band theory of materials,which has become one of the frontiers of current *** immense research activities are not only limited to condensed matter physics,but also are expanded to high-energy physics,chemistry,materials science,and are intimately related to application fields such as quantum computing and *** topological phases of matter have been conceived as building blocks for the next-generation electronics industry,based on the concept of"topological electronics".

关键词： topological realization frontier

A SYSTEM DYNAMICS APPROACH FOR SUSTAINABLE DEVELOPMENT IN THE MIYUN RESERVOIR AREA, CHINA

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Chinese Geographical Science 2002年第2期12卷 157-165页

作者： SUN yan feng,guo Huai cheng,QU Guang yi(Center for Environmental Sciences,Peking University,Beijing 100871,P. R. China) Center for Environmental Sciences Peking University Beijing P. R. China

Miyun Reservoir was designated as the water source of Beijing City in 1982. Since that time, socio economic development in Miyun Area has been slowing due to the restriction of severe environmental standards. More and more attention from the public and government has been paid to the regional sustainable development. And an effective planning for the local society management system is urgently desired. In this study, a regional sustainable development system dynamics model, named MiyunSD, is developed for supporting this planning task. MiyunSD consists of dynamic simulation models that explicitly consider information feedback that governs interactions in the system. Such models are capable of simulating the system′s behavior and predicting its developing situation of the future. For the study case, interactions among a number of system components within a time frame of fifteen years are examined dynamically. Three planning alternatives are carefully considered. The base run is based on an assumption that the existing pattern of human activities will prevail in the entire planning horizon, and the other alternatives are based on previous and present planning studies. The different alternatives will get different system′s environmental and socio economic results. Through analyzing these dynamic results, local authorities may find an optimal way to realize the objectives that the regional environment will be well protected and at the same time the economy will be rapidly developed.

关键词： Miyun reservoir sustainable development model policy management system dynamics

Measurement of Superconductivity and Edge States in Topological Superconductor Candidate TaSe_(3)

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Chinese Physics Letters 2021年第7期38卷 110-115页

作者： Shuai Liu Si-Min Nie yan-Peng Qi yan-feng guo Hong-Tao Yuan Le-Xian yang Yu-Lin Chen Mei-Xiao Wang Zhong-Kai Liu School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Department of Materials Science and Engineering Stanford UniversityStanfordCA 94305USA National Laboratory of Solid State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China State Key Laboratory of Low Dimensional Quantum Physics Department of PhysicsTsinghua UniversityBeijing 100084China Frontier Science Center for Quantum Information Beijing 100084China Department of Physics University of OxfordOxfordOX13PUUK ShanghaiTech Laboratory for Topological Physics Shanghai 201210China

Topological superconductors(TSCs)have been widely investigated in recent years due to their novel physics and ability to host Majorana fermions(MFs)which are key to topological quantum *** the great interest,only a few compounds have been proposed as candidates of intrinsic TSCs,such as iron-based superconductor FeSe_(0.55)Te_(0.45) and 2M-WS_(2).Among them,quasi-one-dimensional superconductor TaSe_(3) possesses fascinating properties such as its simple stoichiometry,layered nature and chemical ***,using scanning tunneling microscope/spectroscopy(STM/STS),we systematically investigate the topography and electronic structure of TaSe_(3).Our STM/STS measurement reveals large atomically flat,defect-free surfaces suitable for the search of MF;electronic density of states consistent with our angle-resolved photoemission result and band-structure calculations,and a uniform superconducting gap with a typical size of∼0.25 ***,additional edge states are observed in the vicinity of the terrace edge,suggesting they may have a topological *** result proves the coexistence of superconductivity and topological electronic structure in TaSe_(3),making it an intriguing platform to investigate topological superconductivity.

关键词： stability topological superconductor

Investigation of the room-temperature photoelectron spectroscopy of type-Ⅱ Weyl semimetal candidate WTe_(2)

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Tungsten 2023年第3期5卷 350-356页

作者： Jian-yang Ding Zheng-Tai Liu Zhe Huang Zhi-Cheng Jiang Yi-Chen yang Zhong-Hao Liu Ji-Shan Liu yan-feng guo Da-Wei Shen State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

Layered transition metal dichalcogenides have novel physical properties and great potential for *** them,WTe2,which has an extremely large unsaturated magnetoresistance and is theoretically predicted to be a type-Ⅱ Weyl semimetal,has been extensively ***,we systematically probe the electronic structure of WTe_(2) at room temperature using high-resolution angle-resolved photoelectron spectroscopy(ARPES).We find that temperature-driven chemical potential shift and Lifshitz transition,which is equivalent to low-energy band structures shift downward by around 50 meV,compared to the results at low *** ARPES experimental results match well with previous theoretical calculations,implying the possible existence of type-Ⅱ Weyl points near the Γ-X ***,as expected,there exists a dominantly electron-like Fermi surface instead of the one with compensated electrons and ***,our ARPES results show that the flat band(FB) lying below the Fermi level(EF) becomes closer to the Fermi level at room temperature,which might start to dominate the transport behavior and lead to the disappearance of the unsaturated giant magnetoresistance *** findings not only reveal the electronic structure features of WTe_(2) at room temperature,but also provide new insights into the development of room-temperature topological quantum devices.

关键词： Weyl semimetal Electronic structure ARPES Compensation effect

Pressure-driven metallization with significant changes of structural and photoelectric properties in two-dimensional EuSbTe_(3)

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Rare Metals 2024年第11期43卷 5943-5952页

作者： Zhi-Kai Zhu Zhong-yang Li Zhen Qin Yi-Ming Wang Dong Wang Xiao-Hui Zeng Fu-yang Liu Hong-Liang Dong Qing-yang Hu Ling-Ping Kong Hao-Zhe Liu Wen-Ge yang yan-feng guo Shuai yan Xuan Fang Wei He Gang Liu State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures MOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materialsand School of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Shanghai 201203China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Poly Technologies INCBeijing 100010China ShanghaiTech Laboratory for Topological Physics ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201204China Sch Sci State Key Lab High Power Semicond LasersChangchun University Science and TechnologyChangchun 130022China Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments(MFree) Shanghai Advanced Research in Physical Sciences(SHARPS)Shanghai 201203China

Two-dimensional materials are widely considered to be highly promising for the development of *** improve the performance of these devices,researchers often employ techniques such as defect ***,pressure is employed as a clean and novel means to manipulate the structural and physical properties of EuSbTe_(3),an emerging two-dimensional *** experimental results demonstrate that the structural phase transformation of EuSbTe_(3)occurs under pressure,with an increase in infrared reflectivity,a band gap closure,and a metallization at *** with X-ray diffraction(XRD)and Raman characterizations,it is evident that the pressure-driven transition from semiconductor Pmmn phase to metallic Cmcm phase causes the disappearance of the charge density ***,at a mild pressure,approximately 2 GPa,the maximum photocurrent of EuSbTe_(3)is three times higher than that at ambient condition,suggesting an untapped potential for various practical applications.

关键词： Pressure Phase transition Metallization Photoresponse Two-dimensional(2D)