The Zeeman effect,a fundamental quantum phenomenon,demonstrates the interaction between magnetic fields and atomic systems.While precise spectroscopic measurements of this effect have advanced significantly,there rema...The Zeeman effect,a fundamental quantum phenomenon,demonstrates the interaction between magnetic fields and atomic systems.While precise spectroscopic measurements of this effect have advanced significantly,there remains a lack of simple,visually accessible demonstration for educational purposes.Here,we present a low-cost experiment that allows for direct visual observation of the Zeeman effect.Our setup involves a flame containing sodium(from table salt)placed in front of a sodium vapor lamp.When a magnetic field is applied to the flame,the shadow cast by the flame noticeably lightens,providing a clear,naked-eye demonstration of the Zeeman effect.Furthermore,we conduct two quantitative experiments using this setup,examining the effects of varying magnetic field strength and sodium concentration.This innovative approach not only enriches the experimental demonstration for teaching atomic physics at undergraduate and high school levels but also provides an open platform for students to explore the Zeeman effect through hands-on experience.展开更多
The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,wo...The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,workable,harmonious,and beautiful villages,thereby accelerating agricultural and rural modernization and better advancing the construction of Chinese modernization.This paper,based on elucidating the scientific connotations and logical pathways of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project and"harmonious and beautiful villages",analyzes the practices of building"harmonious and beautiful villages"in Gansu Province.It proposes learning from the experience of coordinated advancement in the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to strengthen infrastructure and public service construction;learning from the experience of adapting to local conditions to reinforce rural industrial drive and integrated development;learning from the experience of environmental optimization and shaping to accelerate the improvement of human settlements and ecological civilization construction;and learning from the experience of co-construction,co-governance,and sharing to speed up rural governance and spiritual civilization development,thereby aiding the construction of harmonious and beautiful villages in Gansu.展开更多
Exploring the specific environmental impacts and mechanisms of China’s sustainable development pilot policy can enrich and expand China’s institutional and practical experiences,offering valuable insights and refere...Exploring the specific environmental impacts and mechanisms of China’s sustainable development pilot policy can enrich and expand China’s institutional and practical experiences,offering valuable insights and references for advancing global environmental sustainability.This study selects the National Innovation Demonstration Zone for Sustainable Development Agenda(NIDZSDA)as the sample and empirically evaluates the effects of the policy on urban environmental quality,using panel data from 74 prefecture-level cities in China between 2006 and 2020.The findings indicate that the sustainable development policy significantly improves urban environmental quality.Two key mechanisms identified are the aggregation of high-quality talent and the enhancement of technological innovation capabilities.Furthermore,the policy exhibits heterogeneous effects across different types of cities,with more pronounced improvements observed in mega and super cities,as well as in resource-based cities.展开更多
The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In ...The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In this paper, a combined approach of Learning from Demonstration (LfD) and Reinforcement Learning (RL) is proposed for space multi-arm collaborative skill learning. The combination effectively resolves the trade-off between learning efficiency and feasible solution in LfD, as well as the time-consuming pursuit of the optimal solution in RL. With the prior knowledge of LfD, space robotic arms can achieve efficient guided learning in high-dimensional state-action space. Specifically, an LfD approach with Probabilistic Movement Primitives (ProMP) is firstly utilized to encode and reproduce the demonstration actions, generating a distribution as the initialization of policy. Then in the RL stage, a Relative Entropy Policy Search (REPS) algorithm modified in continuous state-action space is employed for further policy improvement. More importantly, the learned behaviors can maintain and reflect the characteristics of demonstrations. In addition, a series of supplementary policy search mechanisms are designed to accelerate the exploration process. The effectiveness of the proposed method has been verified both theoretically and experimentally. Moreover, comparisons with state-of-the-art methods have confirmed the outperformance of the approach.展开更多
With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteris...With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteristic and promising plan of the park was proposed.展开更多
基金the National Natural Science Foundation of China for support under grant No.12305037the Fundamental Research Funds for the Central Universities under grant No.2023NTST017。
文摘The Zeeman effect,a fundamental quantum phenomenon,demonstrates the interaction between magnetic fields and atomic systems.While precise spectroscopic measurements of this effect have advanced significantly,there remains a lack of simple,visually accessible demonstration for educational purposes.Here,we present a low-cost experiment that allows for direct visual observation of the Zeeman effect.Our setup involves a flame containing sodium(from table salt)placed in front of a sodium vapor lamp.When a magnetic field is applied to the flame,the shadow cast by the flame noticeably lightens,providing a clear,naked-eye demonstration of the Zeeman effect.Furthermore,we conduct two quantitative experiments using this setup,examining the effects of varying magnetic field strength and sodium concentration.This innovative approach not only enriches the experimental demonstration for teaching atomic physics at undergraduate and high school levels but also provides an open platform for students to explore the Zeeman effect through hands-on experience.
基金Supported by 2025 Gansu Provincial Party School(Institute of Administration)System Social Science Planning Project(QSDXYB2025046).
文摘The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,workable,harmonious,and beautiful villages,thereby accelerating agricultural and rural modernization and better advancing the construction of Chinese modernization.This paper,based on elucidating the scientific connotations and logical pathways of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project and"harmonious and beautiful villages",analyzes the practices of building"harmonious and beautiful villages"in Gansu Province.It proposes learning from the experience of coordinated advancement in the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to strengthen infrastructure and public service construction;learning from the experience of adapting to local conditions to reinforce rural industrial drive and integrated development;learning from the experience of environmental optimization and shaping to accelerate the improvement of human settlements and ecological civilization construction;and learning from the experience of co-construction,co-governance,and sharing to speed up rural governance and spiritual civilization development,thereby aiding the construction of harmonious and beautiful villages in Gansu.
基金fund support was received from National Social Science Fund of China[Grant No.23BJL010].
文摘Exploring the specific environmental impacts and mechanisms of China’s sustainable development pilot policy can enrich and expand China’s institutional and practical experiences,offering valuable insights and references for advancing global environmental sustainability.This study selects the National Innovation Demonstration Zone for Sustainable Development Agenda(NIDZSDA)as the sample and empirically evaluates the effects of the policy on urban environmental quality,using panel data from 74 prefecture-level cities in China between 2006 and 2020.The findings indicate that the sustainable development policy significantly improves urban environmental quality.Two key mechanisms identified are the aggregation of high-quality talent and the enhancement of technological innovation capabilities.Furthermore,the policy exhibits heterogeneous effects across different types of cities,with more pronounced improvements observed in mega and super cities,as well as in resource-based cities.
基金co-supported by the National Natural Science Foundation of China(No.12372045)the Guangdong Basic and Applied Basic Research Foundation,China(No.2023B1515120018)the Shenzhen Science and Technology Program,China(No.JCYJ20220818102207015).
文摘The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In this paper, a combined approach of Learning from Demonstration (LfD) and Reinforcement Learning (RL) is proposed for space multi-arm collaborative skill learning. The combination effectively resolves the trade-off between learning efficiency and feasible solution in LfD, as well as the time-consuming pursuit of the optimal solution in RL. With the prior knowledge of LfD, space robotic arms can achieve efficient guided learning in high-dimensional state-action space. Specifically, an LfD approach with Probabilistic Movement Primitives (ProMP) is firstly utilized to encode and reproduce the demonstration actions, generating a distribution as the initialization of policy. Then in the RL stage, a Relative Entropy Policy Search (REPS) algorithm modified in continuous state-action space is employed for further policy improvement. More importantly, the learned behaviors can maintain and reflect the characteristics of demonstrations. In addition, a series of supplementary policy search mechanisms are designed to accelerate the exploration process. The effectiveness of the proposed method has been verified both theoretically and experimentally. Moreover, comparisons with state-of-the-art methods have confirmed the outperformance of the approach.
文摘With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteristic and promising plan of the park was proposed.
