Angle-resolved photoemission spectroscopy(ARPES)is one of the most powerful experimental techniques in condensed matter physics.Synchrotron ARPES,which uses photons with high flux and continuously tunable energy,has b...Angle-resolved photoemission spectroscopy(ARPES)is one of the most powerful experimental techniques in condensed matter physics.Synchrotron ARPES,which uses photons with high flux and continuously tunable energy,has become particularly important.However,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 Facility.The 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 eV.In 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.展开更多
In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitud...In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitudinal strong focusing(GLSF).At present,GLSF is the most promising method for realizing high-power short-wavelength coherent radiation with mild requirements on modulation laser power.Its essence is to exploit the ultrasmall natural vertical emittance of an electron beam in a planar storage ring for efficient microbunching formation,like a partial transverse-longitudinal emittance exchange in the optical laser wavelength range.Based on an in-depth investigation of related beam physics,a solution for a GLSF SSMB storage ring that can deliver 1 kW average-power EUV light is presented.The work in this paper,such as the generalized Courant–Snyder formalism,analysis of theoretical minimum emittances,transverse-longitudinal coupling dynamics,and derivation of the bunching factor and modulation strengths for laser-induced microbunching schemes,is expected to be useful not only for the development of SSMB but also for future accelerator light sources in general that demand increasingly precise electron beam phase space manipulations.展开更多
The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa2Ca2Cu3O8+δ(Hg1223)superconductor with a T_(c...The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa2Ca2Cu3O8+δ(Hg1223)superconductor with a Tc of 133 K.Two distinct regions are identified on the cleaved surface:the single Fermi surface region where only one Fermi surface is observed,and the double Fermi surface region where two Fermi surface sheets are resolved coming from both the inner(IP)and outer(OP)CuO2 planes.The electronic structure and superconducting gap are measured on both of these two regions.In both cases,the observed electronic states are mainly concentrated near the nodal region.The momentum dependence of the superconducting gap deviates from the standard d-wave form.These results indicate that the surface electronic structure of Hg1223 behaves more like that of underdoped cuprates.展开更多
Particulate matter(PM)is a heterogeneous mixture of liquid and solid particles suspended in the atmosphere,originating from both natural and anthropogenic sources.PM is particularly harmful because it penetrates deep ...Particulate matter(PM)is a heterogeneous mixture of liquid and solid particles suspended in the atmosphere,originating from both natural and anthropogenic sources.PM is particularly harmful because it penetrates deep into the alveoli,entering the systemic circulation,and smaller particles can reach more distant organs and cause widespread physiological effects[1].展开更多
Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O8+and measured a nearly whole superconducting dome on one surface by in-situ angl...Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O8+and measured a nearly whole superconducting dome on one surface by in-situ angle-resolved photoemission spectroscopy [arXiv: 1805.06450]. Here we study the evolution of the electronic structures of Bi_2Sr_2CaCu_2O8+xusing this technique together with tight binding fits. The tight binding parameters are extracted to study their evolution with doping.展开更多
针对局域网中地址解析协议(address resolution protocol,ARP)欺骗攻击隐蔽性强且传统防御手段配置烦琐的问题,设计了基于eNSP仿真平台的ARP欺骗攻击与防御实验方案。通过搭建仿真网络拓扑,复现了ARP欺骗攻击过程,验证了静态ARP绑定、...针对局域网中地址解析协议(address resolution protocol,ARP)欺骗攻击隐蔽性强且传统防御手段配置烦琐的问题,设计了基于eNSP仿真平台的ARP欺骗攻击与防御实验方案。通过搭建仿真网络拓扑,复现了ARP欺骗攻击过程,验证了静态ARP绑定、虚拟局域网(virtual local area network,VLAN)划分及访问控制列表(access control list,ACL)等防御措施的有效性。实验结果表明,该方案可精准模拟ARP欺骗攻击行为,防御措施能实现100%攻击拦截率,同时有效降低目标主机的系统资源消耗。研究成果可为高校网络安全课程实践教学提供支撑,也为中小企业局域网ARP攻击防护提供实践方案。展开更多
Metal-insulator transition(MIT)in perovskite iridium oxides Srn+1IrnO3n+1represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes...Metal-insulator transition(MIT)in perovskite iridium oxides Srn+1IrnO3n+1represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes place when Srn+1IrnO3n+1(n=1,2)is doped with carriers.While electron-doped Srn+1IrnO3n+1(n=1,2)systems have been extensively investigated,hole-doped samples are still limited.Here,we report the first growth of Fe-doped(hole-doped)Sr3Ir2O7single crystals[Sr_3(Ir1-xFe_x)2O7]with the doping level 0.1≤x≤0.28.An MIT behavior is observed at the doping level of x~0.16 from resistivity measurements.Electronic structures of Fe-doped Sr3Ir2O7have been revealed by angle-resolved photoemission spectroscopy(ARPES)measurements.The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr3Ir2O7.Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr3Ir2O7,thereby offering a powerful strategy to modulate MIT in this material system.展开更多
Pathological cardiac hypertrophy is an early and significant cardiac structural characteristic that contributes to the onset and progression of heart failure(HF).Its mainly structural feature is the abnormally enlarge...Pathological cardiac hypertrophy is an early and significant cardiac structural characteristic that contributes to the onset and progression of heart failure(HF).Its mainly structural feature is the abnormally enlarged cardiomyocyte.Effective intervention targets for abnormally enlarged cardiomyocyte remain to be identified.Previous studies have shown that the cellular shape and size can be regulated by the actin related protein 2/3(Arp2/3)complex,which is an actin-binding protein complex involved in the actin nucleation and assembly.However,the roles of the Arp2/3 complex in cardiomyocyte hypertrophy remain unknown.Here our study identifies its novel roles in the occurrence and development of cardiomyocyte hypertrophy.We found that mRNA levels of all subunits from the Arp2/3 complex are significantly upregulated(P<0.05)in the angiotensin Ⅱ(Ang Ⅱ)-induced neonatal rat primary and H9c2 cardiomyocyte hypertrophy.Further studies showed that siRNA-directed ARPC 2 silencing inhibits the reactivation of fetal genes and enlargement of cardiomyocyte area induced by Ang Ⅱ in neonatal rat primary cardiomyocytes(NRCMs)and H9c2 cells(P<0.05).In addition,the upstream activators of the Arp2/3 complex including SH3 protein interacting with Nck,90 kD(SPIN90)and Ras-related C3 botulinum toxin substrate 1(Rac1)/WASp family Verprolin-homologous protein-2(WAVE-2)are upregulated(P<0.05)in Ang Ⅱ-induced neonatal rat primary and H9c2 cardiomyocyte hypertrophy,indicating the excessive activation of the Arp2/3 complex.We further show that CK666,a specific Arp2/3 complex inhibitor,prevents the reactivation of fetal genes and the enlargement of cardiomyocyte area induced by Ang Ⅱ in NRCMs and H9c2 cells(P<0.05).Our results reveal that the Arp2/3 complex plays a crucial role in Ang Ⅱ-induced cardiomyocyte hypertrophy,which is beneficial to further studies about the molecular mechanisms by which the Arp2/3 complex regulates pathological cardiac hypertrophy.展开更多
基金supported by the National Key R&D Program of the MOST of China(No.2016YFA0300204)the National Natural Science Foundation of China(No.11227902)as part of the SiP·ME2 beamline project。
摘要Angle-resolved photoemission spectroscopy(ARPES)is one of the most powerful experimental techniques in condensed matter physics.Synchrotron ARPES,which uses photons with high flux and continuously tunable energy,has become particularly important.However,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 Facility.The 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 eV.In 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.
基金supported by the National Key Research and Development Program of China(No.2022YFA1603401)National Natural Science Foundation of China(Nos.12035010 and 12342501)+1 种基金Beijing Outstanding Young Scientist Program(No.JWZQ20240101006)the Tsinghua University Dushi Program.
摘要In this study,three specific scenarios of a novel accelerator light source mechanism called steady-state microbunching(SSMB)were studied:longitudinal weak focusing,longitudinal strong focusing,and generalized longitudinal strong focusing(GLSF).At present,GLSF is the most promising method for realizing high-power short-wavelength coherent radiation with mild requirements on modulation laser power.Its essence is to exploit the ultrasmall natural vertical emittance of an electron beam in a planar storage ring for efficient microbunching formation,like a partial transverse-longitudinal emittance exchange in the optical laser wavelength range.Based on an in-depth investigation of related beam physics,a solution for a GLSF SSMB storage ring that can deliver 1 kW average-power EUV light is presented.The work in this paper,such as the generalized Courant–Snyder formalism,analysis of theoretical minimum emittances,transverse-longitudinal coupling dynamics,and derivation of the bunching factor and modulation strengths for laser-induced microbunching schemes,is expected to be useful not only for the development of SSMB but also for future accelerator light sources in general that demand increasingly precise electron beam phase space manipulations.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1401800,2022YFA1604200,2022YFA1403900,2023YFA1406002,2024YFA1408301 and 2024YFA1408100)the National Natural Science Foun-dation of China(Grant Nos.12488201,12374066,12374154,12494593)+2 种基金Quantum Science and Technology-National Science and Technology Major Project(Grant No.2021ZD0301800)CAS Superconducting Research Project(Grant No.SCZX-0101)the Synergetic Extreme Condition User Facility(SECUF).
摘要The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa2Ca2Cu3O8+δ(Hg1223)superconductor with a Tc of 133 K.Two distinct regions are identified on the cleaved surface:the single Fermi surface region where only one Fermi surface is observed,and the double Fermi surface region where two Fermi surface sheets are resolved coming from both the inner(IP)and outer(OP)CuO2 planes.The electronic structure and superconducting gap are measured on both of these two regions.In both cases,the observed electronic states are mainly concentrated near the nodal region.The momentum dependence of the superconducting gap deviates from the standard d-wave form.These results indicate that the surface electronic structure of Hg1223 behaves more like that of underdoped cuprates.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(RS-2025-16064487 and RS-2026-25472831).
摘要Particulate matter(PM)is a heterogeneous mixture of liquid and solid particles suspended in the atmosphere,originating from both natural and anthropogenic sources.PM is particularly harmful because it penetrates deep into the alveoli,entering the systemic circulation,and smaller particles can reach more distant organs and cause widespread physiological effects[1].
基金supported by the Ministry of Science and Technology of China(Grant Nos.2016YFA0401000,2016YFA0300600,2015CB921300,and 2015CB921000)the National Natural Science Foundation of China(Grant Nos.11227903,and 11574371)and the Chinese Academy of Sciences(Grant Nos.XDB07000000,and XDPB08-1)
摘要Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O8+and measured a nearly whole superconducting dome on one surface by in-situ angle-resolved photoemission spectroscopy [arXiv: 1805.06450]. Here we study the evolution of the electronic structures of Bi_2Sr_2CaCu_2O8+xusing this technique together with tight binding fits. The tight binding parameters are extracted to study their evolution with doping.
摘要针对局域网中地址解析协议(address resolution protocol,ARP)欺骗攻击隐蔽性强且传统防御手段配置烦琐的问题,设计了基于eNSP仿真平台的ARP欺骗攻击与防御实验方案。通过搭建仿真网络拓扑,复现了ARP欺骗攻击过程,验证了静态ARP绑定、虚拟局域网(virtual local area network,VLAN)划分及访问控制列表(access control list,ACL)等防御措施的有效性。实验结果表明,该方案可精准模拟ARP欺骗攻击行为,防御措施能实现100%攻击拦截率,同时有效降低目标主机的系统资源消耗。研究成果可为高校网络安全课程实践教学提供支撑,也为中小企业局域网ARP攻击防护提供实践方案。
基金supported by the National Natural Science Foundation of China(Grant No.12074358)the National Key Research and Development Program of China(Grant No.2024YFA1408103)+2 种基金the International Partnership Program of the Chinese Academy of Sciences(Grant No.123GJHZ2022035MI)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the Fundamental Research Funds for the Central Universities(Grant No.WK3510000015)。
摘要Metal-insulator transition(MIT)in perovskite iridium oxides Srn+1IrnO3n+1represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes place when Srn+1IrnO3n+1(n=1,2)is doped with carriers.While electron-doped Srn+1IrnO3n+1(n=1,2)systems have been extensively investigated,hole-doped samples are still limited.Here,we report the first growth of Fe-doped(hole-doped)Sr3Ir2O7single crystals[Sr_3(Ir1-xFe_x)2O7]with the doping level 0.1≤x≤0.28.An MIT behavior is observed at the doping level of x~0.16 from resistivity measurements.Electronic structures of Fe-doped Sr3Ir2O7have been revealed by angle-resolved photoemission spectroscopy(ARPES)measurements.The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr3Ir2O7.Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr3Ir2O7,thereby offering a powerful strategy to modulate MIT in this material system.
摘要Pathological cardiac hypertrophy is an early and significant cardiac structural characteristic that contributes to the onset and progression of heart failure(HF).Its mainly structural feature is the abnormally enlarged cardiomyocyte.Effective intervention targets for abnormally enlarged cardiomyocyte remain to be identified.Previous studies have shown that the cellular shape and size can be regulated by the actin related protein 2/3(Arp2/3)complex,which is an actin-binding protein complex involved in the actin nucleation and assembly.However,the roles of the Arp2/3 complex in cardiomyocyte hypertrophy remain unknown.Here our study identifies its novel roles in the occurrence and development of cardiomyocyte hypertrophy.We found that mRNA levels of all subunits from the Arp2/3 complex are significantly upregulated(P<0.05)in the angiotensin Ⅱ(Ang Ⅱ)-induced neonatal rat primary and H9c2 cardiomyocyte hypertrophy.Further studies showed that siRNA-directed ARPC 2 silencing inhibits the reactivation of fetal genes and enlargement of cardiomyocyte area induced by Ang Ⅱ in neonatal rat primary cardiomyocytes(NRCMs)and H9c2 cells(P<0.05).In addition,the upstream activators of the Arp2/3 complex including SH3 protein interacting with Nck,90 kD(SPIN90)and Ras-related C3 botulinum toxin substrate 1(Rac1)/WASp family Verprolin-homologous protein-2(WAVE-2)are upregulated(P<0.05)in Ang Ⅱ-induced neonatal rat primary and H9c2 cardiomyocyte hypertrophy,indicating the excessive activation of the Arp2/3 complex.We further show that CK666,a specific Arp2/3 complex inhibitor,prevents the reactivation of fetal genes and the enlargement of cardiomyocyte area induced by Ang Ⅱ in NRCMs and H9c2 cells(P<0.05).Our results reveal that the Arp2/3 complex plays a crucial role in Ang Ⅱ-induced cardiomyocyte hypertrophy,which is beneficial to further studies about the molecular mechanisms by which the Arp2/3 complex regulates pathological cardiac hypertrophy.