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High-resolution ARPES endstation for in situ electronic structure investigations at SSRF

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Nuclear Science and Techniques 2021年第3期32卷 94-106页

作者： Yi-Chen Yang Zheng-Tai Liu Ji-Shan Liu Zhong-Hao Liu Wan-Ling Liu Xiang-Le Lu Hong-Ping Mei Ang Li Mao Ye Shan Qiao da-wei shen State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China University of Chinese Academy of Sciences Beijing 100049China

Angle-resolved photoemission spectroscopy(ARPES)is one of the most powerful experimental techniques in condensed matter *** ARPES,which uses photons with high flux and continuously tunable energy,has become particularly ***,an excellent synchrotron ARPES system must have features such as a small beam spot,super-high energy resolution,and a user-friendly operation interface.A synchrotron beamline and an endstation(BL03 U)were designed and constructed at the Shanghai Synchrotron Radiation *** beam spot size at the sample position is 7.5(V)μm×67(H)μm,and the fundamental photon range is 7-165 eV;the ARPES system enables photoemission with an energy resolution of 2.67 meV at21.2 *** addition,the ARPES system of this endstation is equipped with a six-axis cryogenic sample manipulator(the lowest temperature is 7 K)and is integrated with an oxide molecular beam epitaxy system and a scanning tunneling microscope,which can provide an advanced platform for in situ characterization of the fine electronic structure of condensed matter.

关键词： Synchrotron ARPES In situ VUV laser Quantum materials

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

Electronic structure of single-crystalline graphene grown on Cu/Ni(111) alloy film

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Chinese Physics B 2019年第8期28卷 250-253页

作者： Xue-Fu Zhang Zhong-Hao Liu Wan-Ling Liu Xiang-Le Lu Zhuo-Jun Li Qing-Kai Yu da-wei shen Xiao-Ming Xie State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology (SIMIT)Chinese Academy of SciencesShanghai 200050China University of Chinese Academy of Sciences Beijing 100049China School of Physical Science and Technology Shanghai Tech UniversityShanghai 200031China CAS Center for Excellence in Superconducting Electronics (CENSE) Shanghai 200050China

Graphene with a Dirac cone-like electronic structure has been extensively studied because of its novel transport properties and potential application for future electronic *** epitaxially grown graphene,the process conditions and the microstructures are strongly dependent on various substrate materials with different lattice constants and interface *** angle-resolved photoemission spectroscopy,here we report an investigation of the electronic structure of single-crystalline graphene grown on Cu/Ni(111)alloy film by chemical vapor *** a relatively low growth temperature,graphene on Cu/Ni(111)exhibits a Dirac cone-like dispersion comparable to that of graphene grown on Cu(111).The linear dispersions forming Dirac cone are as wide as 2 e V,with the Fermi velocity of approximately 1.1×10^6 m/*** cone opens a gap of approximately 152 meV at the binding energy of approximately 304 *** findings would promote the study of engineering of graphene on different substrate materials.

关键词： single-crystal graphene electronic structure Cu/Ni(111)

Associative fear learning-induced changes in the synchrony of activity between hippocampal CA1 pyramidal cells

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Associative fear learning-induced changes in the synchrony o...

Morphology engineering of ZnO micro/nanostructures under mild conditions for optoelectronic application

中国神经科学学会第十届全国学术会议

作者： Yao WANG wei-da shen Chao DING Zhiru WANG Plasticity of Neural Circuit Lab Key Laboratory of Brain Functional GenomicsMinistry of EducationEast China Normal University

Objective The hippocampus implements its function of initial memory consolidation with the dependence of spontaneous *** raises a possibility that spontaneous oscillations in the hippocampus may undergo some learning-associated changes with the requirement for memory consolidation,an issue that has been *** Using simultaneous whole-cell recordings in anaesthetized rats,we measured the synchrony between spontaneous oscillations of CA1 pyramidal cells in *** We found that,in rats recently（on day 1） receiving an associative learning paradigm of trace fear conditioning,the extent of correlations between the spontaneous oscillations measured simultaneously from CA1 pyramidal cells were increased significantly to a higher level,as compared with that observed in unlearned（naive） *** increase disappeared on day 5 after the learning,indicating a transient increase in the synchrony of CA1 activity accompanying imtial memory storage and consolidation in the *** Our data suggest that a transient increase in the synchrony of membrane-potential oscillations between CA1 pyramidal cells may be used by the hippocampus for initial memory consolidation,with the effect contributing to activity-dependent neuronal plasticity for permanent memory storage in other brain regions.

关键词： oscillation synchrony hippocampus associative learning memory consolidation

来源： cnki会议评论

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 498-503页

作者： Liang Chu Haoyu shen Hudie wei Hongyu Chen Guoqiang Ma Wensheng Yan Institute of Carbon Neutrality and New Energy&School of Electronics and Information Hangzhou Dianzi UniversityHangzhou 310018China School of Applied Physics and Materials Wuyi UniversityJiangmen 529020China

Zinc oxide(ZnO)serves as a crucial functional semiconductor with a wide direct bandgap of approximately 3.37 *** reaction is commonly used in the synthesis of ZnO micro/nanostructures,given its low cost,simplicity,and easy ***,ZnO morphology engineering has become desirable through the alteration of minor conditions in the reaction process,particularly at room *** this work,ZnO micro/nanostructures were synthesized in a solution by varying the amounts of the ammonia added at low temperatures(including room temperature).The formation of Zn^(2+)complexes by ammonia in the precursor regulated the reaction rate of the morphology engineering of ZnO,which resulted in various structures,such as nanoparticles,nanosheets,microflowers,and single ***,the obtained ZnO was used in the optoelectronic application of ultraviolet detectors.

关键词： morphology engineering low temperature ZnO nanosheets microflowers ultraviolet detector

Growth of high-quality perovskite (110)-SrIrO_3 thin films using reactive molecular beam epitaxy

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Chinese Physics B 2018年第8期27卷 578-581页

作者： Kai-Li Zhang Cong-Cong Fan Wan-Ling Liu Yv -Feng Wu Xiang-Le Lu Zheng-Tai Liu Ji-Shan Liu Zhong-Hao Liu da-wei shen State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technoloy（SIMIT）Chinese Academy of Sciences（CAS）Shanghai 200050Chia University of Chinese Academy of Sciences Beijing 100049China School of Physicai Science and Technology ShanghaiTech UniversityShanghai 200031China CAS Center for Excellence in Superconducting Electronics（CENSE） Shanghai 200050China

Recently, 5d transition metal iridates have been reported as promising materials for the manttfacture of exotic quan- tum states. Apart from the semimetallic ground states that have been observed, perovskite SrlrO3 is also predicted to have a lattice-symmetrically protected topological state in the （110） plane due to its strong： spin-orbil coupling and electron correlation. Compared with non-polar （001）-SflrO3, the especial polarity of （110）-SrIrC）3 undoubtedly adds the： difficulty of fabrication and largely impedes the research on its surface states. Here, we have successfully synthesized high-quality （110）-SflrO3 thin films on （110）-SrTiO3 substrates by reactive molecular beam epitaxy fi^r the first time. Both reflec- tion high-energy electron diffraction pattems and x-ray diffraction measurements suggest the expected orientation and outstanding crystallinity. A （1 × 2） surface reconstruction driven from the surface instabiJity, the. same as that reported in （110）-SrTiO3, is observed. The electric transport measurements uncover that （110）-SrIrO3 exhibits a more prominent semimetallic property in comparison to （001）-SrIrO3.

关键词： molecular beam epitaxy iridates topological crystalline metal sunace reconstruction

Hausdorff Measure of Space Anisotropic Gaussian Processes with Non-stationary Increments

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Acta Mathematicae Applicatae Sinica 2025年第1期41卷 114-132页

作者： Jun WANG Zhen-long CHEN wei-jie YUAN Guang-jun shen School of Mathematics and Physics Anhui Polytechnic UniversityWuhu 241000China School of Statistics and Mathematics Zhejiang Gongshang UniversityHangzhou 310018China Department of Mathematics Anhui Normal UniversityWuhu 241000China

Let X={X(t),t∈R+} be a centered space anisotropic Gaussian process values in R^(d) with non-stationary increments,whose components are independent but may not be identically *** certain conditions,then almost surely c_(1)≤ϕ-m(X([0,1]))≤c_(2),where ϕ denotes the exact Hausdorff measure associated with function ϕ(s)=s1/α_(k)+Σ_(i=1)k(1-αi/αk)log log 1/s for some 1≤k≤d,(α_(1),…,α_(d))∈(0,1]^(d).We also obtain the exact Hausdorff measure of the graph of X on[0,1].

关键词： Hausdorff measure self-similar Gaussian processes non-stationary increment Lamperti theorem

Numerical simulation of microstructure and microporosity morphology in directional solidification of aluminum-copper alloys:Effect of copper content and withdrawal rate

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China Foundry 2025年第1期22卷 33-44页

作者： wei Yuan Hai-dong Zhao Xu shen Chun Zou Yuan Liu Qing-yan Xu National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China Key Laboratory for Advanced Materials Processing Technology(Ministry of Education) Tsinghua UniversityBeijing 100084China

Microporosity formed in the solidification process of Al alloys is detrimental to the alloy properties.A two-dimensional cellular automaton(CA)model was developed to simulate the microstructure and microporosity formation in Al-Cu alloys,considering variations in Cu content and solidification *** results indicate that the Cu content primarily influences the growth of *** validate the model,directional solidification experiments were conducted on Al-Cu alloys with varing Cu contents and withdrawal *** experimental results of dendrites and microporosity characteristics agree well with the predictions from the developed model,thus confirming the validity of the *** alloy’s liquidus temperature,dendrite morphology,and hydrogen saturation solubility arising from different Cu contents have significant effects on microporosity *** withdrawal rate primarily affects the nucleation of hydrogen microporosity by altering cooling rates and dendritic growth rates,resulting in different microporosity characteristics.

关键词： microporosity dendrites cellular automaton Al-Cu alloys directional solidification

Ce-UiO-66 nanozymes with charge-regulated uricase-like activity for enzyme/reagent-free detection of uric acid

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Nano Research 2025年第2期18卷 675-686页

作者： Zhixiong Guo da Chen wei Gao Yongquan Qu Zhimin Tian Key Laboratory of Special Functional and Smart Polymer Materials of Ministry of Industry and Information Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710054China State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Designing highly performed uricase-like nanozymes through enzymatic-like colorimetric analysis system is of vital significance for the quantitative detection of uric acid(UA).Herein,series of Ce-UiO-66 nanozymes with different surface charges through the ligand engineering strategy were rationally designed and synthesized as efficient uricase mimics with tailorable uricase-like activities to catalytically convert UA into allantoin and ***,by tuning the functional groups of 1,4-benzoic acid ligands,we explored the relationships between the surface charges of Ce-UiO-66-X(X=H,NO_(2),Br,CH_(3),and OH)nanozymes and their uricase-like *** them,Ce UiO-66-CH_(3) with the moderate surface charge exhibited optimal substrate adsorption and product desorption,displaying the highest uricase-like ***,H2O2,as the product of UA oxidation,enabled Ce-UiO-66-CH_(3) itself as a dose-dependent chromogenic substrate of H_(2)O_(2),giving a white-to-orange color evolution due to the Ce-UiO-66-CH_(3)-to-CeO_(2) phase ***,a smartphone-assisted all-in-one enzyme/reagent-free biosensor based on Ce-UiO-66-CH_(3) was established for the precise visual detection of UA analysis,which was featured by a wide detection range(31–4000µM),a high sensitivity(limit of detection:8.9µM),a rapid response(-3 min),a high structural stability,and a high anti-interference ability.

关键词： Ce-UiO-66 uricase-like nanozyme colorimetric uric acid analysis enzyme/reagent-free detection smartphone