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Journal of Environmental Sciences 2024年第4期138卷 266-276页

作者： Xu Liu Xun Wang dingyong Wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the *** this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at *** in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric *** showed that distinct variabilities among Masson pine tree-ring Hg concentration *** Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric *** found a distinct age effect that the tree ring of young trees had the higher Hg ***,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree *** modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in *** finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

关键词： Masson pine Tree-ring mercury Radial translocation Tree age effect

Uncovering the magnetic response of open-shell graphene nanostructures on metallic surfaces at different doping levels

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 142-148页

作者： Zengfu Ou Jun Wang Jihai Zhang Yukang Ding Shenwei Chen Wenya Zhai Jingcheng Li dingyong Zhong Donghui Guo School of Physics Sun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of PhysicsSun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen UniversityGuangzhou 510275China College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China

Open-shell graphene nanostructures(GNs)are promising candidates for future spintronics and quantum *** progress based on on-surface synthetic approach has successfully created such GNs on metallic ***,the doping effect of metallic surfaces is inevitably present and can significantly tune their electronic and magnetic ***,we investigate the zigzag end states of open-shell 7-armchair graphene nanoribbons(7-AGNRs)on Au(1.1.,Au(1.0)and Ag(1.1.*** with the manipulation of a scanning tunneling microscope,we demonstrate that the end states can be tuned from empty states to singly occupied states and to doubly occupied states by substrate ***,the singly occupied states can be finely tuned,with the occupancy number of the states and related magnetic behaviors uncovered by experiments at different temperatures and magnetic *** results provide a comprehensive study of the magnetic response of open-shell GNs on metallic surfaces at different doping levels.

关键词： open-shell graphene nanostructures magnetic response metallic substrate doping Kondo resonance scanning tunneling microscopy/spectroscopy

Coastal hypoxia response to the coupling of catastrophic flood,extreme marine heatwave and typhoon:a case study off the Changjiang River Estuary in summer 2020

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Acta Oceanologica Sinica 2024年第6期43卷 107-118页

作者： Xiao Ma Qicheng Meng Dewang Li Yuanli Zhu Xiaobo Ni dingyong Zeng Di Tian Ting Huang Zhihao Jiang Haiyan Jin Feng Zhou State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Observation and Research Station of Yangtze River Delta Marine Ecosystems Ministry of Natural ResourcesZhoushan 316022China Key Laboratory of Marine Ecosystem Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200240China College of Oceanography Zhejiang UniversityZhoushan 316021China

Massive bodies of low-oxygen bottom waters are found in coastal areas worldwide,which are detrimental to coastal *** summer 2020,the response of coastal hypoxia to extreme weather events,including a catastrophic flooding,an extreme marine heatwave,and Typhoon Bavi,is investigated based on multiple satellite,four cruises,and mooring *** extensive fan-shaped hypoxia zone presents significant northward extension during July-September 2020,and is estimated as large as 1. 000 km^(2) with rather low oxygen minimum(0.42 mg/L) during its peak in 28-30 *** severe hypoxia is attributed to the persistent strong stratification,which is indicated by flood-induced larger amount of riverine freshwater input and subsequent marine heatwave off the Changjiang River ***,the Typhoon Bavi has limited effect on the marine heatwave and coastal hypoxia in summer 2020.

关键词： coastal hypoxia Changjiang River Estuary extreme weather events seasonal evolution

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新时代地勘单位精细化管理研究

中国矿业 2024年第4期33卷 99-104页

作者：刘定勇湖南省水文地质环境地质调查监测所湖南长沙410014

新时代下高质量发展为地勘行业提出了新的任务,也为广大地质工作者提供了新的发展机遇。尤其是在新一轮找矿突破战略行动的背景下,地勘单位要找准工作定位,主动承担任务。但当前地勘单位普遍存在同质化恶性竞争激烈、科技创新能力不足... 详细信息

新时代下高质量发展为地勘行业提出了新的任务,也为广大地质工作者提供了新的发展机遇。尤其是在新一轮找矿突破战略行动的背景下,地勘单位要找准工作定位,主动承担任务。但当前地勘单位普遍存在同质化恶性竞争激烈、科技创新能力不足、新兴地质专业人才缺乏等问题,严重制约地勘单位的转型发展。因此,地勘单位应改变传统的管理模式,实现精细化管理,确保管理高效、科学,从而更好地促进发展。据此,分析了地勘单位精细化管理的含义、特征,以及地勘单位实现精细化管理的意义,并提出了地勘单位精细化管理应从加强目标设计与细化、严密规范制定制度和流程、增强目标执行力、加强各方沟通合作、问题导向与解决、注重细节管理等途径得以实现,以期通过精细化管理提升地勘单位核心竞争力,为地勘行业高质量发展做出贡献。

关键词：地勘单位地质勘查精细化管理地质找矿高质量发展

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新时代地矿文化转型发展研究

中国矿业 2024年第7期33卷 26-30页

作者：刘定勇湖南省水文地质环境地质调查监测所湖南长沙410014

地矿文化作为地矿行业的精神财富,不仅承载着地质工作者的奋斗历程和精神追求,也是推动地矿行业实现高质量发展的重要精神力量。尤其在新时代下,地矿文化不仅是地质工作和矿业发展的精神支柱,也是推动社会文明进步和文化繁荣的重要力量... 详细信息

地矿文化作为地矿行业的精神财富,不仅承载着地质工作者的奋斗历程和精神追求,也是推动地矿行业实现高质量发展的重要精神力量。尤其在新时代下,地矿文化不仅是地质工作和矿业发展的精神支柱,也是推动社会文明进步和文化繁荣的重要力量。本文对地矿文化进行概述,梳理地质文化与矿业文化的关系,厘清广义地矿文化与狭义地矿文化的含义,并论述地矿文化的价值与作用。结合新时代地矿行业发展需要,分析了地矿文化转型发展的基本内涵,即从单向发展向开放融合发展转变、从低水平循环向高质量发展转变、从重资源向资源与环境并重转变、从重经济向经济与文化并重转变、从重传承向传承与创新并重转变。在此基础上,提出了新时代地矿文化转型发展的路径,主要包括发掘传统地矿文化优秀资源、夯实地矿行业高质量发展基础、打造新时代地矿精神高地、构建新时代地矿文化体系、推进地矿文化开放创新发展。地矿文化以其特有的内涵影响着地矿行业的发展模式、制度选择、政策取向,以及各种资源开发和生产要素组合的水平,从而影响行业发展的速度、质量和水平。因此,地矿文化转型具有重要意义,以期能够为地矿行业发展和国家资源安全提供坚实的文化支撑。

关键词：地矿文化地质文化地矿行业新时代地质勘查地勘单位

选区激光熔化成形NiTi合金工艺参数对表面粗糙度的影响规律

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表面技术 2024年第9期53卷 200-208页

作者：王俊伟贺定勇吴旭王国红北京工业大学材料科学与工程学院北京100124

目的针对选区激光熔化(SLM)制备NiTi形状记忆合金表面粗糙度难以满足实际应用要求,通过优化工艺参数(激光功率、扫描速度、扫描间距)以有效地降低表面粗糙度以及研究各工艺参数对表面粗糙度的影响规律。方法采用L1.正交阵列的田口模型... 详细信息

目的针对选区激光熔化(SLM)制备NiTi形状记忆合金表面粗糙度难以满足实际应用要求,通过优化工艺参数(激光功率、扫描速度、扫描间距)以有效地降低表面粗糙度以及研究各工艺参数对表面粗糙度的影响规律。方法采用L1.正交阵列的田口模型设计选区激光熔化制备NiTi样品的工艺参数,通过对表面粗糙度信噪比值进行统计方法分析以及样品表面形貌的表征,研究不同工艺参数对表面粗糙度的影响程度以及影响机理,最终优化出制备低表面粗糙度的工艺参数组合。结果在激光功率为20 W和30 W时,NiTi粉末不能够充分熔化造成熔道不连续,使得样品表面起伏增大,粗糙度值最大到7.8μm;增大激光功率到40W和50W时,粉末充分熔化,样品表面形貌明显改善;在相同功率下,扫描速度从200mm/s增加到500mm/s时,样品的粗糙度值也随之增大。结论工艺参数对表面粗糙度影响的重要性顺序依次为激光功率、扫描速度、扫描间距;最终优化出的工艺参数组合为激光功率50W、扫描速度200mm/s、扫描间距0.07mm,并在该工艺参数下制备的样品表面粗糙度值为1.38μm,与模型预测的值1.43μm接近,相差仅为9.97%。

关键词：选区激光熔化 NiTi形状记忆合金田口方法表面粗糙度工艺优化

维普期刊数据库博看期刊

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振荡流下二维单椭圆柱体水动力特性研究

水动力学研究与进展（A辑） 2024年第3期39卷 425-433页

作者：阮黎于定勇李现琦房子昂中国海洋大学工程学院青岛266404

椭圆柱体的流线型结构有助于降低应力集中,增强结构稳定性。为研究椭圆柱体在振荡流作用下的水动力特性,该文利用Fluent数值模拟了雷诺数Re=200,迎流角度θ=1.°、30°、45°、60°、75°和90°,轴长比R_(A)=0.5、0.6、0.7、0.8和0.9的... 详细信息

椭圆柱体的流线型结构有助于降低应力集中,增强结构稳定性。为研究椭圆柱体在振荡流作用下的水动力特性,该文利用Fluent数值模拟了雷诺数Re=200,迎流角度θ=1.°、30°、45°、60°、75°和90°,轴长比R_(A)=0.5、0.6、0.7、0.8和0.9的椭圆柱体绕流过程,分析了柱体的流场特性和水动力参数等变化规律。结果表明:振荡流正向来流时,小轴长比的椭圆柱体尾涡沿顺流方向发展,随着轴长比及迎流角度的增大,椭圆柱体尾涡的强度、尺寸、脱落周期和影响范围增大,柱体两侧脱落的涡对数量增多,尾流迹线增长,偏转角度增大;迎流角度θ=0°~90°时,随着θ的增大,椭圆柱体的拖曳力系数C_(D)不断增大,惯性力系数C_(M)先减小后增大,升力系数均方根C_(l-rms)先增大后减小,C_(M)和C_(l-rms)均在θ=45°时最大;θ≤30°时,椭圆柱体可发挥减阻效果。该研究结果可为相关工程设计提供参考。

关键词：振荡流椭圆柱体迎流角度轴长比

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生物标志物在结核病诊断中的研究进展

中国防痨杂志 2024年第6期46卷 713-721页

作者：徐文辉张艳秋石洁孙定勇郑州大学公共卫生学院流行病学系郑州450001 河南省疾病预防控制中心结核病预防控制所郑州450016

结核病是全球性的公共卫生问题,结核分枝杆菌生物标志物可以用于结核病的早期诊断和治疗监测。但现有结核病诊断方法存在不足,亟需寻找新的易获取的快速诊断结核病的生物标志物,以探索快速诊断结核病的新方法。本综述介绍了来源于血液... 详细信息

结核病是全球性的公共卫生问题,结核分枝杆菌生物标志物可以用于结核病的早期诊断和治疗监测。但现有结核病诊断方法存在不足,亟需寻找新的易获取的快速诊断结核病的生物标志物,以探索快速诊断结核病的新方法。本综述介绍了来源于血液、尿液、唾液及其他样本的结核病生物标志物最新研究进展,为开发新型结核病诊断方法提供线索。

关键词：结核生物因子生物学标记诊断综述文献(主题)

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Effect of dissolved organic matter on adsorption and desorption of mercury by soils

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Journal of Environmental Sciences 2008年第9期20卷 1097-1102页

作者： YANG, Yongkui LIANG, Li WANG, dingyong College of Resources and Environment Southwest University Chongqing 400716 China Chongqing Key Lab of Agricultural Resources and Environment Chongqing 400716 China

Effects of dissolved organic matter (DOM) on adsorption and desorption of Hg were investigated in two kinds of soils, Xanthi-Udic Ferralosols (XUF) and Typic Purpli-Udic Cambosols (TPUC). The DOM was obtained from humus soil (DOMH), rice straw (DOMR), and pig manure (DOMP). The presence of DOM obviously reduced Hg maximum adsorption capacity with up to 40% decreases over the control, being an order of DOMH (250.00 mg/kg)1..67 mg/kg) for the...

关键词： mercury (Hg) dissolved organic matter (DOM) adsorption desorption

Modulation of low-frequencyoscillations in GaAs MESFETs’ channel current by sidegating bias

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Chinese Science Bulletin 2005年第9期50卷 932-935页

作者： dingyong LUShengli ZHAOFuchuan NationalEngineeringResearchCenterForApplicationSpecificIntegratedCircuitSystem SoutheastUniversityNanjing210096China

Low-frequency oscillations in channel current are usually observed when measuring the GaAs MESFET’s output characteristics. This paper studies the oscillations by testing the MESFET’s output characteristics under different sidegate bias conditions. It is shown that the low-frequency oscillations of channel current are directly related to the sidegate bias. In other words, the sidegate bias can modulate the oscillations. Whether the sidegate bias varies positively or negatively, there will inevitably be a threshold voltage after which the low-frequency oscillations disappear. The observa- tion is strongly dependent upon the peculiarities of chan- nel-substrate (C-S) junction and impact ionization of traps-EL2 under high field. This conclusion is of particular pertinence to the design of low-noise GaAs IC’s.

关键词：通信技术低频振动信道底层连接撞击电离输出频率