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Recrystallization nucleation under close-setδphase in a nickel-based superalloy during annealing

Journal of Materials Science & Technology 2022年第20期115卷 166-176页

作者： guanqiang wang Mingsong Chen Yongcheng Lin Hongbin Li Yuqiang Jiang Yanyong Ma Chengxu Peng Jinliang Cai Quan Chen School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China Light Alloy Research Institute Central South UniversityChangsha 410083China State Key Laboratory of High Performance Complex Manufacturing Changsha 410083China College of metallurgies and energy North China University of Science and TechnologyTangshan 063009China

Annealing is one of the most efficient heat treatment to refine the grain microstructure in metal alloys.Prior to the annealing,an aging treatment can be implemented to precipitate the second phases for more nucleation sites in deformed mixed grains during subsequent recrystallization.However,the underlying mechanism behind the second phases and recrystallization has not yet been fully understood.Taking a typical deformed nickel(Ni)-based(GH4169)superalloy as an exapmle,this research aims to clairfy the connections between the recrystallization and delta(δ)phase(Ni_(3)Nb) during annealing.All deformed samples were also treated by aging and then annealing.The results show that the microstructure and component ofδphase dominated the recrystallization nucleation in the Ni-based alloy.Moreover,there was the presence of theδphase interval limiting nucleation(PILN)andδphase protecting nucleation(PPN),when a high content of close-set phase was precipitated from the matrix.The PILN determined the primary condition for the recrystallization nucleation that happended at the interval ofδphase larger than the critical nucleation size.The peak nucleation occurred in the PPN,where the recrystallization nucleus were free of the penetration by the adjacent grains,before the nucleation incubation time was reached.Thus,a new feasible JNtheory was proposed to determine the maximum domain of recrystallization nucleation under close-set precipitated phases.All the possible nucleation sites were assumed under PPN in the JNtheory.As such,the original microstructure can be expected to design for the annealing via the aging process.A quantitative evaluation of recrystallization nucleation can also achieved in the Ni-based alloys during aging.

关键词： Nickel-based superalloy δphase Recrystallization Nucleation Metal alloys

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精英运动员身体再造的符号解读与图式建构

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成都体育学院学报 2024年第2期50卷 85-92页

作者：赵妍杨冠强王智慧中国人民大学社会与人口学院北京100872 中国人民大学体育部北京100872 中国人民大学社会学理论与方法研究中心北京100872

为进一步拓展身体社会学的理论边界,以精英运动员的身体再造为切入点,通过揭示其价值认同、符号意涵,建构出内在机理所蕴含的身体图式。研究发现:(1)精英运动员无限接近人类身体潜能的再造过程可以被定义为“意指进阶”。(2)精英运动员... 详细信息

为进一步拓展身体社会学的理论边界,以精英运动员的身体再造为切入点,通过揭示其价值认同、符号意涵,建构出内在机理所蕴含的身体图式。研究发现:(1)精英运动员无限接近人类身体潜能的再造过程可以被定义为“意指进阶”。(2)精英运动员的身体再造是规训话语表征于运动展演和行为互动的镜像,同时也是社会文化表征于身体价值与观念的镜像。(3)精英运动员身体再造具有形塑社会秩序、推进社会再生产以及塑立文化符号标识三重属性,并在“身体消费”和表征社会变迁的结构化行动中使运动态身体、商品态身体以及社会态身体形成联结。(4)精英运动员的身体再造图式是该群体在以身体实践感为基础,以互动情境链为桥连、以身体仪式嵌入为核心的运作机制中,通过“存在—规训—展演—象征”复合性实践型构的一种特定文化样态。

关键词：身体图式仪式互动情境链身体规训价值认同情感能量

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Assessment of tree-ring mercury radial translocation and age effect in Masson pine:Implications for historical atmospheric mercury reconstruction

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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 reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The 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 Chongqing.We 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

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Pushing the boundaries: an interview with Dae-Hyun Kim on terahertz devices

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National Science Review 2024年第3期11卷 42-45页

作者： Defu wang the Center for Carbon-based Electronics School of Electronics Peking University

Ⅲ–Ⅴ compound semiconductors, such as InGaAs/InAlAs, exhibit exceptional carrier transport properties, establishing them as fundamental elements in terahertz(THz) applications crucial for the development of 6G netwo...

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Enrichment of anammox biomass during mainstream wastewater treatment driven by achievement of partial denitrification through the addition of bio-carriers

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Journal of Environmental Sciences 2024年第3期137卷 181-194页

作者： Yuqing Ma Bo wang Xiaodi Li Shuo wang Wen wang Yongzhen Peng National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology Engineering Research Center of BeijingBeijing University of TechnologyBeijing 100124China

Anammox is widely considered as the most cost-effective and sustainable process for nitrogen removal.However,how to achieve the enrichment of anammox biomass remains a challenge for its large-scale application,especially in mainstream wastewater treatment.In this study,the feasibility of enrichment of anammox biomass was explored through the realization of partial denitrification and the addition of bio-carriers.By using ordinary activated sludge,a sequencing batch reactor(SBR)followed by an up-fow anaerobic sludge bed(UASB)was operated at 25±2℃ for 214 days.The long-term operation was divided into five phases,in which SBR and UASB were started-up in Phases I and II,respectively.By eliminating oxygen and adjusting the infow ratios in Phases III-V,advanced nitrogen removal was achieved with the effuent total nitrogen being 4.7 mg/L and the nitrogen removal efficiency being 90.5%in Phase V.Both in-situ and ex-situ activity tests demonstrated the occurrence of partial denitrification and anammox.Moreover,16S rRNA high-throughput sequencing analysis revealed that Candidatus Brocadia was enriched from below the detection limit to in biofilms(0.4%in SBR,2.2%in UASB)and the foc sludge(0.2%in SBR,1.3%in UASB),while Thauera was mainly detected in the foc sludge(8.1%in SBR,8.8%in UASB),which might play a key role in partial denitrification.Overall,this study provides a novel strategy to enrich anammox biomass driven by rapid achievement of partial denitrification through the addition of bio-carriers,which will improve large-scale application of anammox processes in mainstream wastewater treatment.

关键词： Enrichment Anammox biomass Bio-carriers Partial denitrification Mainstream wastewater

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Performance and mechanism of La-Fe metal-organic framework as a highly efficient adsorbent for fluoride removal from mine water

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Journal of Environmental Sciences 2024年第5期139卷 245-257页

作者： Chaomin Jia Jianbing wang Huijiao wang Sichao Zhu Xiaohui Zhang Yuxiang wang School of Chemical&Environmental Engineering China University of Mining&Technology-BeijingBeijing 100083China Beijing Polytechnic Beijing 100176China Chinese Society for Urban Studies Beijing 100835China

Water fluoride pollution has caused non-negligible harm to the environment and humans,and thus it is crucial to find a suitable treatment technology.In this study,La-Fe@PTA adsorbent was synthesized for the defluoridation of mine water.The results showed that the optimum conditions for defluoridation by La-Fe@PTA were p H close to 7.0,the initial F-concentration of 10 mg/L,the dosage of 0.5 g/L and the adsorption time of 240 min.Compared with SO_4^(2-),Cl^(-),NO_(3)^(-),Ca^(2+)and Mg^(2+),CO_(3)^(2-)and HCO_(3)^(-)presented severer inhibition on fluoride uptake by La-Fe@PTA.The adsorption process fits well with the pseudo-second-order kinetic model and Freundlich model,and the maximum adsorption capacity of Langmuir model was 95 mg/g.Fixed-bed adsorption results indicated that fluoride in practical fluorinated mine water could be effectively removed from 3.6 mg/L to less than 1.5 mg/L within130 bed volume(BV)by using 1.5 g La-Fe@PTA.Furthermore,the adsorbent still had good adsorption capacity after regeneration,which confirms the great application potential of La-Fe@PTA as a fluoride ion adsorbent.The mechanism analysis showed that La-Fe@PTA adsorption of fluorine ions is a physicochemical reaction driven by electrostatic attraction and ion exchange.

关键词： Adsorption La-Fe@PTA Fluoride ion Mine water Mechanism

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烟气凝变过程中SO_(3)酸雾凝结长大与脱除特性模拟研究

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中国电机工程学报 2024年第6期44卷 2301-2309,I0018页

作者：裴婷马素霞赵贯甲王鹏宋冠强米晨锋太原理工大学电气与动力工程学院山西省太原市030027

烟气冷凝技术能够回收湿烟气中的废水和余热,同时降低SO_(3)酸雾排放量。该文通过建立烟气冷凝、颗粒运动及颗粒凝结长大模型,对烟气凝变过程中SO_(3)酸雾的凝结长大和脱除特性进行研究,分析关键影响因素,并讨论了酸雾长大和脱除机理。... 详细信息

烟气冷凝技术能够回收湿烟气中的废水和余热,同时降低SO_(3)酸雾排放量。该文通过建立烟气冷凝、颗粒运动及颗粒凝结长大模型,对烟气凝变过程中SO_(3)酸雾的凝结长大和脱除特性进行研究,分析关键影响因素,并讨论了酸雾长大和脱除机理。结果表明:SO_(3)酸雾经过凝结长大后在换热器出口粒径呈双峰分布,最高数量浓度在微米范围;亚微米粒径的酸雾捕集机理以热泳和扩散泳为主,提高入口烟气温度和相对湿度,降低壁面温度和入口烟气流速都有利于酸雾粒径的增长和脱除。微米粒径的酸雾捕集机理以惯性碰撞和拦截为主,提高烟气流速有助于微米粒径酸雾的脱除。

关键词：凝变换热器数值模拟脱除效率饱和度

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Analysis of Hot Topics Regarding Global Smart Elderly Care Research—1997-2021

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China CDC weekly 2024年第9期6卷 157-161页

作者： Hongman wang Hong Chen Yuqi wang School of Health Humanities Peking UniversityBeijingChina Center for Global Public Health Chinese Center for Disease Control and PreventionBeijingChina

Summary What is already known about this topic?With the assistance of the internet,big data,cloud computing,and other technologies,the concept of smart elderly care has emerged.What is added by this report?This study presents information on the countries or regions that have conducted research on smart elderly care,as well as identifies global hotspots and development trends in this field.

关键词： Smart internet smart

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Continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

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Light(Science & Applications) 2024年第3期13卷 446-453页

作者： Ziye wang Xia Liu Pinyao wang Huanyu Lu Bo Meng Wei Zhang Lijie wang Yanjing wang Cunzhu Tong State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Central Research Institute Planning Dept 2012 LabsHuawei Technologies Company Ltd.Shenzhen 518129China

Benefitting from narrow beam divergence,photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and ranging.Lasers operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe threshold.However,high interband absorption significantly decreases their performance at this 1.55μm wavelength.Therefore,stronger optical feedback is needed to reduce their threshold and thus improve the output power.Toward this goal,photonic-crystal resonators with deep holes and high dielectric contrast are often used.Nevertheless,the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final yield.In this paper,we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a‘triple-lattice photonic-crystal resonator’,which superimposes three lattice point groups to increase the strength of in-plane optical feedback.Using this geometry,the in-plane 180°coupling can be enhanced threefold compared to the normal single-lattice structure.Detailed theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to‘single-lattice’and‘double-lattice’photonic-crystal resonators,verifying our design principles.Our findings provide a new strategy for photonic crystal laser miniaturization,which is crucial for realizing their use in future high-speed applications.

关键词： resonator crystal lattice

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Determining an optimal control strategy for anthropogenic VOC emissions in China based on source emissions and reactivity

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Journal of Environmental Sciences 2024年第2期136卷 248-260页

作者： Ruipeng wang Xiaoqi wang Shuiyuan Cheng Jiaxian Zhu Xinyu Zhang Long Cheng Kai wang Key Laboratory of Beijing on Regional Air Pollution Control Faculty of Environment and LifeBeijing University of TechnologyBeijing 100124China

An evidence-based control strategy for emission reduction of VOC sources can effectively solve the regional PM2.5and O3compound pollution in China.We estimated the anthropogenic VOC emission inventory in China in 2018 and established a source profile database containing 129 sources based on localized detection and the latest research results.Then,the distribution of the ozone formation potential(OFP)and secondary organic aerosol formation potential(SOAFP)for emission sources was analyzed.Moreover,priority control routes for VOC emission sources were proposed for different periods.Anthropogenic VOC emissions in China reached 27,211.8 Gg in 2018,and small passenger cars,industrial protective coatings,biomass burning,heavy trucks,printing,asphalt paving,oil storage and transportation,coking,and oil refining were the main contributors.Industrial protective coatings,small passenger cars,and biomass burning all contributed significantly to OFP and SOAFP.Priority in emission reduction control should be given to industrial protective coatings,small passenger cars,heavy trucks,coking,printing,asphalt paving,chemical fibers,and basic organic chemical sources over the medium and long term in China.In addition,the priority control route for VOC emission sources should be adjusted according to the variations in VOC emission characteristics and regional differences,so as to obtain the maximum environmental benefits.

关键词： Volatile organic compounds Anthropogenic emission inventory Reactivity Emission projection Priority control route

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