As the core carrier of Lingnan culture and a nationally famous historical&cultural city,Guangzhou preserves more than 3000 immovable historic buildings,including arcade rows,ancestral halls,Xiguan mansions and mod...As the core carrier of Lingnan culture and a nationally famous historical&cultural city,Guangzhou preserves more than 3000 immovable historic buildings,including arcade rows,ancestral halls,Xiguan mansions and modern public edifices.Their brick-timber hybrid structures,high-density“bambootube”street pattern and hot-humid subtropical climate create unique fire challenges.This study systematically summarizes an“inherent-acquired-environmental”superimposed fire-risk mechanism.By integrating traditional Cantonese fire-resistance wisdom—such as Qingyun fire lanes,wok-ear gables and courtyard smoke vents—and heritage-friendly innovations,a three-level policy-technology-management protection framework is established.Hierarchical protection aligned with value grading,life-cycle technology pathways and multistakeholder collaboration is proposed.The“minimum-intervention and performance-based”route and the“regulation-guideline-standard”policy loop developed by Guangzhou reduce the fire incidence of priority historic buildings while retaining heritage authenticity,offering a replicable paradigm for balancing fire safety and conservation in hot-humid,high-density contexts.展开更多
Millisecond isomers were recently observed in ^(213,215)Tl.These two isomers can be interpreted by the π 0h 11/2- single-proton-hole states.The 11/2−states in Tl isotopes decrease in energy when neutrons are added to...Millisecond isomers were recently observed in ^(213,215)Tl.These two isomers can be interpreted by the π 0h 11/2- single-proton-hole states.The 11/2−states in Tl isotopes decrease in energy when neutrons are added to the ν0g_(9/2) orbital,as driven by the protonneutron monopole interaction.Based on the mechanism,this work investigates the isomerism in the southeastern vicinity of ^(208)Pb with an optimized shell-model effective Hamiltonian.The 11/2−isomericγ-decay half-lives are predicted to be longer in more neutron-rich nuclei,potentially exceeding theβ-decay half-lives.In this way,βdecay may predominantly occur in the 11/2−states,which are crucial for understanding the N=126 waiting points and the A=195 peak.展开更多
The Jiangmen Underground Neutrino Observatory(JUNO)started physics data taking on 26 August 2025.JUNO consists of a 20-kton liquid scintillator central detector,surrounded by a 35 kton water pool serving as a Cherenko...The Jiangmen Underground Neutrino Observatory(JUNO)started physics data taking on 26 August 2025.JUNO consists of a 20-kton liquid scintillator central detector,surrounded by a 35 kton water pool serving as a Cherenkov veto,and almost 1000 m^(2) of plastic scintillator veto on top.The detector is located in a shallow underground laboratory with an overburden of 1800 m.w.e.This paper presents the performance results of the detector,extensively studied during the commissioning of the water phase,the subsequent liquid scintillator filling phase,and the first physics runs.The liquid scintillator achieved an attenuation length of 20.6 m at 430 nm,while the high coverage PMT system and scintillator together yielded about 1785 photoelectrons per MeV of energy deposit at the detector centre,measured using the 2.223 MeVγfrom neutron captures on hydrogen with an Am-C calibration source.The reconstructed energy resolution is 3.4%for two 0.511 MeVγat the detector centre and 2.9%for the 0.93 MeV quenched ^(214)Po alpha decays from natural radioactive sources.The energy non-linearity is calibrated to better than 1%.Intrinsic contaminations of ^(238)U and ^(232)Th in the liquid scintillator are below 10^(-16) g/g,assuming secular equilibrium.The water Cherenkov detector achieves a muon detection efficiency better than 99.9%for muons traversing the liquid scintillator volume.During the initial science runs,the data acquisition duty cycle exceeded 97.8%,demonstrating the excellent stability and readiness of JUNO for high-precision neutrino physics.展开更多
基金supported by Guangzhou Railway Polytechnic(No.GTXYRC 250107)Guangzhou Municipal Education Bureau(No.2025YBJG010).
文摘As the core carrier of Lingnan culture and a nationally famous historical&cultural city,Guangzhou preserves more than 3000 immovable historic buildings,including arcade rows,ancestral halls,Xiguan mansions and modern public edifices.Their brick-timber hybrid structures,high-density“bambootube”street pattern and hot-humid subtropical climate create unique fire challenges.This study systematically summarizes an“inherent-acquired-environmental”superimposed fire-risk mechanism.By integrating traditional Cantonese fire-resistance wisdom—such as Qingyun fire lanes,wok-ear gables and courtyard smoke vents—and heritage-friendly innovations,a three-level policy-technology-management protection framework is established.Hierarchical protection aligned with value grading,life-cycle technology pathways and multistakeholder collaboration is proposed.The“minimum-intervention and performance-based”route and the“regulation-guideline-standard”policy loop developed by Guangzhou reduce the fire incidence of priority historic buildings while retaining heritage authenticity,offering a replicable paradigm for balancing fire safety and conservation in hot-humid,high-density contexts.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (Grant No. 2021B0301030006)the National Natural Science Foundation of China (Grant Nos. 12475129, 12405144, and 12305129)+2 种基金the International Atomic Energy Agency Coordinatated Research Project F41034 (Grant No. 28649)the Computational Resources from Sun Yat-sen University and Fudan Universitythe National Supercomputer Center in Guangzhou
文摘Millisecond isomers were recently observed in ^(213,215)Tl.These two isomers can be interpreted by the π 0h 11/2- single-proton-hole states.The 11/2−states in Tl isotopes decrease in energy when neutrons are added to the ν0g_(9/2) orbital,as driven by the protonneutron monopole interaction.Based on the mechanism,this work investigates the isomerism in the southeastern vicinity of ^(208)Pb with an optimized shell-model effective Hamiltonian.The 11/2−isomericγ-decay half-lives are predicted to be longer in more neutron-rich nuclei,potentially exceeding theβ-decay half-lives.In this way,βdecay may predominantly occur in the 11/2−states,which are crucial for understanding the N=126 waiting points and the A=195 peak.
文摘The Jiangmen Underground Neutrino Observatory(JUNO)started physics data taking on 26 August 2025.JUNO consists of a 20-kton liquid scintillator central detector,surrounded by a 35 kton water pool serving as a Cherenkov veto,and almost 1000 m^(2) of plastic scintillator veto on top.The detector is located in a shallow underground laboratory with an overburden of 1800 m.w.e.This paper presents the performance results of the detector,extensively studied during the commissioning of the water phase,the subsequent liquid scintillator filling phase,and the first physics runs.The liquid scintillator achieved an attenuation length of 20.6 m at 430 nm,while the high coverage PMT system and scintillator together yielded about 1785 photoelectrons per MeV of energy deposit at the detector centre,measured using the 2.223 MeVγfrom neutron captures on hydrogen with an Am-C calibration source.The reconstructed energy resolution is 3.4%for two 0.511 MeVγat the detector centre and 2.9%for the 0.93 MeV quenched ^(214)Po alpha decays from natural radioactive sources.The energy non-linearity is calibrated to better than 1%.Intrinsic contaminations of ^(238)U and ^(232)Th in the liquid scintillator are below 10^(-16) g/g,assuming secular equilibrium.The water Cherenkov detector achieves a muon detection efficiency better than 99.9%for muons traversing the liquid scintillator volume.During the initial science runs,the data acquisition duty cycle exceeded 97.8%,demonstrating the excellent stability and readiness of JUNO for high-precision neutrino physics.
