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Migration mechanism of atrazine in the simulated lake icing process at different freezing temperatures based on density function theory
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作者 Yan Zhang Hao Lin +5 位作者 Aixin Yu xiaozhuang wang Yucan Liu Tongshuai Liu Chen Zhao Rui Mei 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第10期45-54,共10页
Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms,causing pollution in lakes.This study measured the concentration of atrazine in ice and the water under ice ... Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms,causing pollution in lakes.This study measured the concentration of atrazine in ice and the water under ice through a simulated icing experiment and calculated the distribution coefficient K to characterize its migration ability in the freezing process.Furthermore,density functional theory(DFT)calculations were employed to expatiate the migration law of atrazine during icing process.According to the results,it could release more energy into the environment when atrazine staying in water phase(-15.077 kcal/mol)than staying in ice phase(-14.388 kcal/mol),therefore it was beneficial for the migration of atrazine from ice to water.This explains that during the freezing process,the concentration of atrazine in the ice was lower than that in the water.Thermodynamic calculations indicated thatwhen the temperature decreases from268 to 248 K,the internal energy contribution of the compound of atrazine and ice molecule(water cluster)decreases at the same vibrational frequency,resulting in an increase in the free energy difference of the compound from-167.946 to-165.390 kcal/mol.This demonstrated the diminished migratory capacity of atrazine.This study revealed the environmental behavior of atrazine during lake freezing,which was beneficial for the management of atrazine and other pollutants during freezing and environmental protection. 展开更多
关键词 Density functional theory(DFT) Icing process ATRAZINE Migration behavior Free energy
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年长员工退休后继续工作动机的影响因素及群体间比较:基于网络分析法 被引量:2
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作者 王晓庄 孟鸿兴 李洪玉 《中国人力资源开发》 CSSCI 北大核心 2023年第8期37-53,共17页
关于年长员工对衰老和时间的观念和认知、对工作特征相关因素的感知及其与退休后继续工作动机的关系,还缺乏充分的研究证据和结论。本研究基于动机生命周期发展理论和社会情感选择理论,采用网络分析方法,通过两次问卷调查收集的887名年... 关于年长员工对衰老和时间的观念和认知、对工作特征相关因素的感知及其与退休后继续工作动机的关系,还缺乏充分的研究证据和结论。本研究基于动机生命周期发展理论和社会情感选择理论,采用网络分析方法,通过两次问卷调查收集的887名年长员工数据,考察年长员工继续工作动机的影响因素及不同年长员工群体的网络结构差异。结果表明:(1)影响年长员工退休后继续工作动机因素的核心节点为工作自主性、职业剩余机会、组织支持感和非本质主义信念。(2)不同性别年长员工的网络结构和核心节点存在显著差异,男性网络图中,工作自主性、职业剩余机会与退休后继续工作动机的联系更为密切;而女性网络图中,非本质主义信念、组织支持感与退休后继续工作动机的联系更为密切。(3)不同职业和单位性质的年长员工群体网络核心节点存在显著差异,商业服务业年长员工的网络图中,组织支持感的中介中心性高于其他职业;机关事业单位年长员工的网络图中,工作自主性的强度中心性高于企业单位。本文深化了对年长员工退休后继续工作动机相关因素及群体差异的认识,为开展年长员工生涯管理及助推延迟退休政策实施提供了新视角。 展开更多
关键词 年长员工 退休后继续工作动机 网络分析法
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Study of MRPC technology for BESIII endcap-TOF upgrade
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作者 Xin Li Yongjie Sun +18 位作者 Cheng Li Zhen Liu Yuekun Heng Ming Shao xiaozhuang wang Zhi Wu Ping Cao Mingming Chen Hongliang Dai Shubing Liu Xiaolan Luo Xiaoshan Jiang Shengsen Sun Zebo Tang Weijia Sun Siyu wang Meihang Xu Rongxing Yang Kejun Zhu 《Radiation Detection Technology and Methods》 2017年第2期31-36,共6页
Purpose In order to improve the charged particle identi-fication capability,end-cap time-of-flight(ETOF)detector of the Beijing Spectrometer(BESIII)has been upgraded with multi-gap resistive plate chamber(MRPC)technol... Purpose In order to improve the charged particle identi-fication capability,end-cap time-of-flight(ETOF)detector of the Beijing Spectrometer(BESIII)has been upgraded with multi-gap resistive plate chamber(MRPC)technology,aiming at an overall time resolution of 80 ps for minimum-ionization particles to extend the K/πseparation(2σ)momentum range to 1.4 GeV/c.Methods The previous version of ETOF in BESIII consisted of plastic scintillators.The multi-hit events distort both shape and amplitude of the output signals.MRPC technique was chosen for the BESIII ETOF upgrade as it provides high time resolution and high detection efficiency,is of relatively low cost and is insensitive to neutral particles.Most importantly,the fine segmentation of the MRPC readout stripes can suppress multi-hit events effectively.Results The final design of MRPC module for ETOF is characterized by double-stack(2×6)structure,dual-end readout mode and precision electronics.To batch-produce and test these MRPC modules,a series of tools and production procedures as well as related performance simulation and test methods were developed.Results showed that each MRPC module’s intrinsic time resolution(including the electronics contribution)is around 50 ps and the efficiency is better than 97%.The overall performance of the upgraded ETOF is better than the designed index.The new ETOF has been successfully installed at BESIII and run in 2016. 展开更多
关键词 Multi-gap resistive plate chamber Endcap time-of-flight detector Particle identification Beijing spectrometer High time resolution
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