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A novel and promising engineering application of carbon dots:Enhancing the chloride binding performance of cement

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Chinese Chemical Letters 2024年第6期35卷 409-416页

作者： Wu-Jian Long Yang yu Chuang he Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Key Lab of Coastal Urban Resilient InfrastructureMOECollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

Corrosion of reinforcement induced by chloride invasion is extensively considered as the dominating deterioration mechanism of reinforced concrete(RC)structures,leading to serious safety hazards and tremendous economic ***,it still lacks well dispersive and cost-efficient nanomaterials to improve the anti-chloride-corrosion ability of RC ***,specific carbon dots(CDs)with high dispersity and low cost are deliberately designed,successfully prepared by hydrothermal processing,and then firstly applied to immensely enhance chloride binding performance of cement,thereby contributing to suppressing the corrosion of ***,the tailored CDs are composed of the carbon core with highly crystalline sp^(2)C structures and oxygen-containing groups connecting on the carbon core;The typical equilibrium test confirms that with respect to that of the blank cement paste,the chloride binding capacity of cement paste involving 0.2 wt%(by weight of cement)CDs is increased by 109% after 14-day exposure to 3 mol/L Na Cl solution;according to comprehensive analyses of phase compositions,the chloride binding mechanism of CDs-modified cement is rationally attributed to the fact that the incorporation of CDs advances the formation of calcium silicate hydrate(C-S-H)gels and Friedel's salt(Fs),thus enormously enhancing the physically adsorbed and chemically bound chloride ions of cement *** work not only firstly provides a novel high-dispersity and low-cost nanomaterial toward the durability enhancement of RC structures,but also broadens the application of CDs in the field of engineering,conducing to stimulating their industrialization development.

关键词： Carbon dots Chloride binding Cement Chloride binding mechanism Friedel’s salt

High-entropy design boosts dielectric energy storage

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Rare Metals 2024年第8期43卷 4013-4015页

作者： Qiu-ying Xia he Zhu Si Lan Yang Ren herbert Gleiter Institute of Nanoscience School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Physics City University of Hong KongHong Kong999077China

Dielectric capacitors are vital for advanced electronic and electrical power systems due to their impressive power density and ***,a persistent challenge has been enhancing their energy densities while maintaining high *** in Science,a novel high-entropy design for relaxor ferroelectric materials has been proposed,promising significant improvements in both energy density and efficiency for multilayer dielectric ceramic *** the crucial role of high-entropy design in energy storage materials and devices,this highlight focuses on interpreting the progress and significance of this innovative work.

关键词： ceramic dielectric energy

Understory seedlings of Quercus mongolica survive by phenological escape

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Forest Ecosystems 2024年第2期11卷 236-246页

作者： Shixiong Wu ying Liu Lulu he Wei Zeng Qijing Liu College of Forestry Beijing Forestry UniversityBeijing100083China

Understanding understory seedling regeneration mechanisms is important for the sustainable development of temperate primary forests in the context of increasingly intense climate warming *** poor regeneration of dominant tree species,however,is one of the biggest challenges it faces at the ***,the regeneration of the shade-intolerant Quercus mongolica seedling is difficult in primary forests,which contrasts with the extreme abundance of understory seedlings in secondary *** mechanism behind the interesting phenomenon is still *** study used in-situ monitoring and nursery-controlled experiment to investigate the survival rate,growth performance,as well as nonstructural carbohydrate (NSC) concentrations and pools of various organ tissues of seedlings for two consecutive years,further analyze the understory light availability and simulate the foliage carbon (C) gain in the secondary and primary *** suggested that seedlings in the secondary forest had greater biomass allocation aboveground,height and specific leaf area (SLA) in summer,which allowed the seedling to survive longer in the canopy closure *** light availability and positive C gain in early spring and late autumn are key factors affecting the growth and survival of understory seedlings in the secondary forest,whereas seedlings in the primary forest had annual negative carbon *** the growing season,the total NSC concentrations of seedlings gradually decreased,whereas those of seedlings in the secondary forest increased significantly in autumn,and were mainly stored in roots for winter consumption and the following year's summer shade period,which was verified by the nursery-controlled experiment that simulated autumn enhanced light availability improved seedling survival rate and NSC *** conclusion,our results revealed the survival trade-off strategies of Quercus mongolica seedlings and highlighted the necessity of high light availability d

关键词： Carbon gain Nonstructural carbohydrate Recruitment Trade-off Biomass allocation

Effects of impregnation sequence on the NH_(3)-SCR activity and hydrothermal stability of a Ce-Nb/SnO_(2) catalyst

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Journal of Environmental Sciences 2024年第4期138卷 450-457页

作者： ying Zhu Wenpo Shan Zhihua Lian Jingjing Liu Yan Zhang Hong he Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control Ningbo Urban Environment Observation and Research StationInstitute of Urban EnvironmentChinese Academy of SciencesNingbo 315800China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Hydrothermal stability is crucial for the practical application of deNO_(x)catalyst on diesel vehicles,for the selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).SnO_(2)-based materials possess superior hydrothermal stability,which is attractive for the development of NH_(3)-SCR *** this work,a series of Ce-Nb/SnO_(2)catalysts,with Ce and Nb loading on SnO_(2)support,were prepared by impregnation *** was found that,the NH_(3)-SCR activities and hydrothermal stabilities of the Ce-Nb/SnO_(2)catalysts significantly varied with the impregnation sequences,and the Ce-Nb(f)/SnO_(2) catalyst that firstly impregnated Nb and then impregnated Ce exhibited the best *** characterization results revealed that CeNb(f)/SnO_(2)possessed appropriate acidity and redox ***,the strong synergistic effect between Nb and Sn species stabilized the structure and maintained the dispersion of acid *** study may provide a new understanding for the effect of impregnation sequence on activity and hydrothermal stability and a new environmental-friendly NH_(3)-SCR catalyst with potential applications for NO_(x)removal from diesel and hydrogenfueled engines.

关键词： NO_(x)emission control NH_(3)-SCR Hydrothermal stability Ce-Nb/SnO_(2)catalyst Impregnation sequence

Early endoscopic management of an infected acute necrotic collection misdiagnosed as a pancreatic pseudocyst: A case report

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World Journal of Gastrointestinal Surgery 2024年第2期16卷 609-615页

作者： Hong-ying Zhang Chen-Cong he Department of Gastroenterology Jinhua People's HospitalJinhua 321000Zhejiang ProvinceChina Department of General Medicine Jinhua Guangfu HospitalJinhua 321001Zhejiang ProvinceChina

BACKGROUND Infected acute necrotic collection(ANC)is a fatal complication of acute pancre-atitis with substantial morbidity and *** plays an exceedingly important role as the first step in invasive intervention for infected necrosis;however,there is great controversy about the optimal drainage time,and better treatment should be *** SUMMARY We report the case of a 43-year-old man who was admitted to the hospital with severe intake reduction due to early satiety 2 wk after treatment for acute pancre-atitis;conservative treatment was ineffective,and a pancreatic pseudocyst was suspected on contrast-enhanced computed tomography(CT).Endoscopic ultra-sonography(EUS)suggested hyperechoic necrotic tissue within the cyst *** wall was not completely mature,and the culture of the puncture fluid was positive for A-haemolytic ***,the final diagnosis of ANC in-fection was *** necrotic collection was not walled off and contained many solid components;therefore,the patient underwent EUS-guided aspiration and *** weeks after the collection was completely encapsulated,pancreatic duct stent drainage via endoscopic retrograde cholangiopancreatography(ERCP)was performed,and the patient was subsequently successfully *** repeat CT,the pancreatic cysts had almost disappeared during the 6-month fo-llow-up period after *** Early EUS-guided aspiration and lavage combined with late ERCP catheter drainage may be effective methods for intervention in infected ANCs.

关键词： Infected acute necrotic collection Pancreatic pseudocyst Endoscopic ultrasonography Endoscopic retrograde cholangiopancreatography Endoscopic ultrasound-guided fine-needle aspiration Case report

Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

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China Foundry 2024年第1期21卷 51-59页

作者： Dong Pan Qing-tao Guo Kai-lun Zhang Fu-zhi yu yu-ying Li yu-bao Xiao State Key Laboratory of Metal Materials for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Beijing Research Institute Co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring *** a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation

Inverse Calculation and Regularization Process for the Solar Aspect System(SAS) of HXI Payload on ASO-S Spacecraft

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Research in Astronomy and Astrophysics 2024年第4期24卷 13-34页

作者： Ji-Rui yu Ping Ruan Yang Su ying-Hong he Jin-You Tao Zhe Zhang Song Guo Bin Xue Jian-Feng Yang Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences Xi'an 710119China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 20034China School ofAstronomy and Space Science Universityof Science and Technology of ChinaHefei 230026China

For the ASO-S/HXI payload, the accuracy of the flare reconstruction is reliant on important factors such as the alignment of the dual grating and the precise measurement of observation orientation. To guarantee optimal functionality of the instrument throughout its life cycle, the Solar Aspect System (SAS) is imperative to ensure that measurements are accurate and reliable. This is achieved by capturing the target motion and utilizing a physical model-based inversion algorithm. However, the SAS optical system’s inversion model is a typical ill-posed inverse problem due to its optical parameters, which results in small target sampling errors triggering unacceptable shifts in the solution. To enhance inversion accuracy and make it more robust against observation errors, we suggest dividing the inversion operation into two stages based on the SAS spot motion model. First, the as-rigid-aspossible (ARAP) transformation algorithm calculates the relative rotations and an intermediate variable between the substrates. Second, we solve an inversion linear equation for the relative translation of the substrates, the offset of the optical axes, and the observation orientation. To address the ill-posed challenge, the Tikhonov method grounded on the discrepancy criterion and the maximum a posteriori (MAP) method founded on the Bayesian framework are utilized. The simulation results exhibit that the ARAP method achieves a solution with a rotational error of roughly±3 5 (1/2-quantile);both regularization techniques are successful in enhancing the stability of the solution, the variance of error in the MAP method is even smaller—it achieves a translational error of approximately±18μm (1/2-quantile) in comparison to the Tikhonov method’s error of around±24μm (1/2-quantile). Furthermore, the SAS practical application data indicates the method’s usability in this study. Lastly, this paper discusses the intrinsic interconnections between the regularization methods.

关键词： methods:data analysis Sun:flares Sun:X-rays gamma rays

Evolution of Biofilm and Its Effect on Microstructure of Mortar Surfaces in Simulated Seawater

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 234-243页

作者：荣辉 yu Chenglong 张颖 School of Materials Science and Engineering Tianjin Chengjian UniversityTianjin 300384China Tianjin Key Laboratory of Building Green Functional Materials Tianjin Chengjian UniversityTianjin 300384China

To explore the role of biofilm formation on the corrosion of marine concrete structures, we investigated the attachment of biofilm on mortar surfaces in simulated seawater and the influence of biofilm on the microstructure of mortar surfaces. The results show that the evolution of biofilm on mortar surfaces in simulated seawater is closely related to the corrosion suffered by the mortar, and the process of biofilm attachment and shedding is continuous and cyclical. It is found that the specimens in the absence of biofilm attachment are more severely eroded internally by the corrosive medium in simulated seawater than those in the presence of biofilm attachment. For the specimens without biofilm attachment, after 60 days, gypsum forms,and after 120 days, the number of pores in the mortar is reduced. In contrast, for the specimens in the presence of biofilm attachment, gypsum could only be detected after 90 days, and fewer pores are filled. Therefore, the formation of biofilm could delay the invasion of the corrosive medium into the interior of mortar during the evolution of biofilm on mortar surfaces, mitigating the corrosion of mortars in seawater.

关键词： biofilm attachment mortar sulfur-oxidizing bacteria gypsum simulated seawater microstructure

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玩具资源服务功能之价值探索

图书馆工作与研究 2007年第5期 107-108页

作者：何瑜英杭州少年儿童图书馆浙江杭州310007

以玩具资源为载体,吸引幼儿来到图书馆;以快乐体验为媒介,激发幼儿亲近图书馆,由此达到培育幼儿阅读习惯的目的。

关键词：玩具亲近图书馆阅读习惯