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Fringe visibility and distinguishability in two-path interferometer with an asymmetric beam splitter

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Chinese Physics B 2019年第3期28卷 109-113页

作者： Yanjun Liu Jing Lu Zhihui Peng Lan Zhou Dongning Zheng Key Laboratory of Low-Dimensional Quantum structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center of Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China Beijing National Laboratory for Condnesed Matter Physics and Institute of Physics Beijing 100190China CAS center for excellence in Topological Quantum Computation and School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Songshan Lake Materials Laboratory DongguanGuangdong 523808China

We study the fringe visibility and the distinguishability of a general Mach-Zehnder interferometer with an asymmetric beam splitter. Both the fringe visibility V and the distinguishability D are affected by the input state of the particle characterized by the Bloch vector S =(S_x, S_y, S_z) and the second asymmetric beam splitter characterized by the paramterβ. For the total system is initially in a pure state, it is found that the fringe visibility reaches the upper bound and the distinguishability reaches the lower bound when cosβ=-S_x, The fringe visibility obtain the maximum only if S_x = 0 and β = π/2 when the input particle is initially in a mixed state. The complementary relationship V^2 +D^2 ≤ 1 is proved in a general Mach-Zehnder interferometer with an asymmetric beam splitter, and the conditions for the equality are also presented.

关键词： complementarity fringe visibility distinguishability general Mach–Zehnder interferometer

A biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties and accelerating osseointegration in spinal fusion

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Bioactive Materials 2023年第5期23卷 234-246页

作者： Cheng-Qi Jia Zhen Zhang Shi-Qi Cao Tian-Jiao Wang Hai-Chao Yu Wen-Xiang Wang Bo-Min Guo Xiong-Ying Qiu Yong-Gang You Fan-Qi Hu Jun Zhao Xue-Song Zhang Medical School of Chinese PLA Beijing100853China department of Orthopedics Chinese PLA General HospitalBeijing100853China department of Orthopedics of TCM Clinical Unit 6th Medical CenterChinese PLA General HospitalBeijing100853China Research Institute of Aerospace Special Materials and Processing Technology Beijing100074China CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190China Academy of Military Medical Sciences Academy of Military SciencesBeijing100080China University of Chinese Academy of Sciences Beijing100049China

Objectives:Spinal fusion is a widely employed treatment of patients with degenerative disc disease,in which a cage is used to replace the disc for spinal *** it often fails for insufficient mechanical strength and poor ***,we designed a polyether-ether-ketone(PEEK)/tantalum(Ta)composite cage with a biomimetic gradient porous micro-structure,simultaneously enhancing mechanical properties and accelerating osseointegration in spinal *** and methods:In the study,based on the mechanical performances of PEEK and osteogenic potential of Ta,and the three-dimensional(3D)structures of cuttlebone and vertebra,the cages were respectively 3D printed by pure PEEK,PEEK with 5 wt%Ta(PEEK/Ta-5),PEEK with 10 wt%Ta(PEEK/Ta-10)and PEEK with 15 wt%Ta(PEEK/Ta-15),then verifiedin vitroand in sheep cervical fusion model ***:Vertebral Gyroid structure PEEK/Ta-15 cage exhibited superior mechanical properties than Cuttlebone-like structure PEEK/Ta-15 cage,closer to the cervical ***,PEEK/Ta-15 cage with higher Ta microparticles in PEEK provided a biomimetic gradient porous micro-structure with higher surface energy,guiding cell biological behavior,promoting new bone penetration,and accelerating osseointegrationin vivo.Conclusion:In conclusion,the study designed a biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties,accelerating osseointegration and forming an anatomical lock in the fusion segment through composites,mechanical efficiency,surface extension,and pores.

关键词： Biomimetic Porous Composite Osseointegration Spinal fusion

Electroluminescence from pure resonant states in hBN-based vertical tunneling junctions

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Light(Science & Applications) 2024年第8期13卷 1557-1564页

作者： Magdalena Grzeszczyk Kristina Vaklinova Kenji Watanabe Takashi Taniguchi Konstantin SNovoselov Maciej Koperski Institute for Functional Intelligent Materials National University of SingaporeSingapore 117544Singapore Research center for Functional Materials National Institute for Materials ScienceTsukuba 305-0044Japan International center for Materials Nanoarchitectonics National Institute for Materials ScienceTsukuba 305-0044Japan department of Materials Science and Engineering National University of SingaporeSingapore 117575Singapore

Defect centers in wide-band-gap crystals have garnered interest for their potential in applications among optoelectronic and sensor ***,defects embedded in highly insulating crystals,like diamond,silicon carbide,or aluminum oxide,have been notoriously difficult to excite electrically due to their large internal *** address this challenge,we realized a new paradigm of exciting defects in vertical tunneling junctions based on carbon centers in hexagonal boron nitride(hBN).The rational design of the devices via van der Waals technology enabled us to raise and control optical processes related to defect-to-band and intradefect *** fundamental understanding of the tunneling events was based on the transfer of the electronic wave function amplitude between resonant defect states in hBN to the metallic state in graphene,which leads to dramatic changes in the characteristics of electrons due to different band structures of constituent *** our devices,the decay of electrons via tunneling pathways competed with radiative recombination,resulting in an unprecedented degree of tuneability of carrier dynamics due to the significant sensitivity of the characteristic tunneling times on the thickness and structure of the *** enabled us to achieve a high-efficiency electrical excitation of intradefect transitions,exceeding by several orders of magnitude the efficiency of optical excitation in the sub-band-gap *** work represents a significant advancement towards a universal and scalable platform for electrically driven devices utilizing defect centers in wide-band-gap crystals with properties modulated via activation of different tunneling mechanisms at a level of device engineering.

关键词： carbide tunneling defect

Nanoscale architecture of ceria-based model catalysts: Pt-Co nanostructures on well-ordered CeO_(2)(111) thin films

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Chinese Journal of Catalysis 2020年第6期41卷 985-997页

作者： Yaroslava Lykhach TomásSkála Armin Neitzel Nataliya Tsud Klára Beranová Kevin CPrince Vladimír Matolín Jorg Libuda Interface Research and Catalysis Erlangen Catalysis Resource CenterFriedrich-Alexander-Universit?t Erlangen-NürnbergEgerlandstrasse 391058 ErlangenGermany Charles University Faculty of Mathematics and PhysicsDepartment of Surface and Plasma ScienceV Hole?ovi?kách 218000 PragueCzech Republic Elettra-Sincrotrone Trieste SCpA Strada Statale 14km 163.534149 Basovizza-TriesteItaly

We have prepared and characterized atomically well-defined model systems for ceria-supported Pt-Co core-shell catalysts. Pt@Co and Co@Pt core-shell nanostructures were grown on well-ordered CeO2(111) films on Cu(111) by physical vapour deposition of Pt and Co metals in ultrahigh vacuum and investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy. The deposition of Co onto CeO2(111) yields CoCeO2(111) solid solution at low Co coverage(0.5 ML), followed by the growth of metallic Co nanoparticles at higher Co coverages. Both Pt@Co and Co@Pt model structures are stable against sintering in the temperature range between 300 and 500 K. After annealing at 500 K, the Pt@Co nanostructure contains nearly pure Co-shell while the Pt-shell in the Co@Pt is partially covered by metallic Co. Above 550 K, the re-ordering in the near surface regions yields a subsurface Pt-Co alloy and Pt-rich shells in both Pt@Co and Co@Pt nanostructures. In the case of Co@Pt nanoparticles, the chemical ordering in the near surface region depends on the initial thickness of the deposited Pt-shell. Annealing of the Co@Pt nanostructures in the presence of O2 triggers the decomposition of Pt-Co alloy along with the oxidation of Co, regardless of the thickness of the initial Pt-shell. Progressive oxidation of Co coupled with adsorbate-induced Co segregation leads to the formation of thick CoO layers on the surfaces of the supported Co@Pt nanostructures. This process is accompanied by the disintegration of the CeO2(111) film and encapsulation of oxidized Co@Pt nanostructures by CeO2 upon annealing in O2 above 550 K. Notably, during oxidation and reduction cycles with O2 and H2 at different temperatures, the changes in the structure and chemical composition of supported Co@Pt nanostructures were driven mainly by oxidation while reduction treatments had little effect regardless of the initial thickness of the Pt-shell.

关键词： Core-shell nanoparticles Model catalyst Pt-Co Cerium oxide Chemical ordering Synchrotron radiation photoelectron spectroscopy

Nitrogen doped FeS_(2) nanoparticles for efficient and stable hydrogen evolution reaction

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Journal of Energy Chemistry 2021年第5期30卷 283-289页

作者： Jian Ye Yipeng Zang Qingyu Wang Yida Zhang Da Sun Leijie Zhang Gongming Wang Xusheng Zheng Junfa Zhu National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029AnhuiChina School of Science Anhui Agricultural UniversityHefei 230036AnhuiChina Hefei National Laboratory for Physical Science at the Microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

Performance breakthrough of electrocatalysts highly relies on the regulation of internal structures and electronic *** present work,for the first time,we successfully synthesized nitrogen doped FeS_(2) nanoparticles(N-FeS_(2))as the electrocatalysts for hydrogen evolution reaction(HER).The band structure and electronic state of FeS_(2) are modulated by a nitrogen doping strategy,as confirmed by X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS)and density functional theory(DFT)*** to the band structure and electronic state regulation as well as the weakening of H-S interaction,the designed N-FeS_(2) electrocatalyst exhibits superior catalytic performance with a low overpotential(~126 mV at 10 mA cm^(-2))and excellent activity stability under alkaline conditions,which is substantially improved as compared with that of the pure FeS_(2) *** work demonstrates that the modulation of electron state and band structure of an electrocatalyst,which can provide a valuable guidance for designing excellent catalysts for hydrogen evolution reaction and beyond.

关键词： Ferric sulfide Nitrogen dopant Nanoparticles Electrocatalyst Hydrogen evolution reactio

Introducing sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction in SnS_(2) nanosheets to promote photocatalytic activity

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Chinese Chemical Letters 2020年第10期31卷 2809-2813页

作者： Keyan Hu Chen Ming Yiting Liu Chong Zheng Shaoning Zhang Dong Wang Wei Zhao Fuqiang Huang State Key Laboratory of High-Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China School of Mechanical and Electrical Engineering Jingdezhen Ceramic InstituteJingdezhen 333403China State Key Laboratory of Precision Spectroscopy East China Normal UniversityShanghai 200062China department of Chemistry and Biochemistry Northern Illinois UniversityDeKalbIllinois 60115United States Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Due to the relatively sluggish charge carrier separation in metal sulfides,the photocatalytic activity of them is still far lower than ***,sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction were successfully introduced into the SnS_(2) nanosheets through high energy *** defective structures were studied by the electron paramagnetic resonance,Raman spectra,X-ray photoelectron spectroscopy,and high-resolution transmission electron microscope *** sulfur vacancies and in-plane heterojunctions strongly accelerate the separation of photoexcited electron-hole pairs,as confirmed by the photo luminesce nce emission spectra and time-resolved photoluminescence decay *** introduction of sulfur vacancies and in-plane heterojunction in SnS_(2) nanosheets results in roughly six times higher photodegrading rate for methyl orange and four times higher photocatalytic reduction rate of Cr6+than those of pure SnS_(2) nanosheets.

关键词： Sulfur vacancies In-plane heterojunction SnS_(2)Nanosheets Ball-milling Charge carrier separation