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Catalysis by subsurface metal atoms in Al(001) through electron transfer

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National Science Review 2024年第4期11卷 12-13页

作者： bo sun Ding Ma Beijing National Laboratory for Molecular Science New Cornerstone Science Laboratory College of Chemistry and Molecular Engineering Peking University

Heterogeneous catalysis plays a crucial role in the chemical industry, which has evolved from the investigation of chemisorption to an electronic structure[1]. Diverse strategies, such as alloying,doping, and confining, have been applied to enhance the catalytic properties of active sites through electronic modulation. The electron transfer between active sites and substrates profoundly influences catalytic activity [2].

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Catalytic recycling of polyesters via a binuclear catalyst

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Science China Chemistry 2024年第2期67卷 426-427页

作者： bo sun Ding Ma Beijing National Laboratory for Molecular Science New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

Plastics play a crucial role in modern society life. While the increasing use of plastics and rapid accumulation of plastic waste in nature environment have caused severe environmental crisis and the waste of carbon resources. Catalytic upcycling is a promising approach to transform plastic waste into high value-added chemicals to achieve a sustainable circular economy.

关键词： Catalytic polyester catalyst

Effect and Mechanism of Rare Earth Hydrotalcite Inhibiting Coal Spontaneous Combustion

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 50-59页

作者：张小娟 LIU bo 罗振敏 sun Lu School of Safety Science and Engineering Xi’an University of Science and TechnologyXi’an 710054China

A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.

关键词： rare earth hydrotalcite coal spontaneous combustion mechanism

Heat transfer and temperature evolution in underground mininginduced overburden fracture and ground fissures: Optimal time window of UAV infrared monitoring

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International Journal of Mining Science and Technology 2024年第1期34卷 31-50页

作者： Yixin Zhao Kangning Zhang bo sun Chunwei Ling Jihong guo Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources China University of Mining and Technology-BeijingBeijing 100083China School of Energy&Mining Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China

Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this study, discrete element software UDEC was employed to investigate the overburden fracture field under different mining conditions. Multiphysics software COMSOL were employed to investigate heat transfer and temperature evolution of overburden fracture and ground fissures under the influence of mining condition, fissure depth, fissure width, and month alternation. The UAV infrared field measurements also provided a calibration for numerical simulation. The results showed that for ground fissures connected to underground goaf(Fissure Ⅰ), the temperature difference increased with larger mining height and shallow buried depth. In addition, Fissure Ⅰ located in the boundary of the goaf have a greater temperature difference and is easier to be identified than fissures located above the mining goaf. For ground fissures having no connection to underground goaf(Fissure Ⅱ), the heat transfer is affected by the internal resistance of the overlying strata fracture when the depth of Fissure Ⅱ is greater than10 m, the temperature of Fissure Ⅱ gradually equals to the ground temperature as the fissures’ depth increases, and the fissures are difficult to be identified. The identification effect is most obvious for fissures larger than 16 cm under the same depth. In spring and summer, UAV infrared identification of mining fissures should be carried out during nighttime. This study provides the basis for the optimal time and season for the UAV infrared identification of different types of mining ground fissures.

关键词： Heat transfer Overburden fracture ground fissures Infrared thermal imaging Unmanned aerial vehicle(UAV) COMSOL simulation

Temporal changes in mixing effects on litter decay and nitrogen release in a boreal riparian forest in northeastern China

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Journal of Forestry Research 2024年第2期35卷 33-41页

作者： Simin Wang bo Liu Rui Li Xiaoxin sun Rong Mao Key Laboratory of National Forestry and grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricultural UniversityNanchang 330045People’s Republic of China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102People’s Republic of China Key Laboratory of Sustainable Forest Ecosystem Management of Ministry of Education School of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China Heilongjiang Sanjiang Plain Wetland Ecosystem Research Station Fuyuan 156500People’s Republic of China

In riparian forests,litter decay provides essential energy and nutrients for both terrestrial and fluvial *** mixing effects(LMEs)are crucial in regulating litter decay and nutrient dynamics,yet how LMEs change over time is unclear in riparian *** this study,leaf litter of three common species(Alnus sibirica *** Turcz,Betula platyphylla Sukaczev,and Betula fruticosa Pall.)were mixed in an equal mass ratio and LMEs were measured for mass and nitrogen(N)remaining in whole litter mixtures over a 3-year period in a boreal riparian forest,northeastern *** were also assessed for component litter mass and N remaining by separating litter mixtures by *** the decay of litter mixtures,antagonistic effects on mass and N remaining were dominant after one and two years of decay,whereas only additive effects were observed after three *** correlated negatively with functional diversity after the first and two years of decay but disappeared after three *** sorting litter mixtures by species,non-additive LMEs on mass and N remaining decreased over incubation ***,non-additive LMEs were more frequent for litter of both *** and *** with lower N concentration than for *** litter with higher N *** results indicate that incubation time is a key determinant of litter mixing effects during decay and highlight that late-stage litter mixture decay may be predicted from single litter decay dynamics in boreal riparian forests.

关键词： Biodiversity Litter quality Litter mixtures Synergistic effects Functional diversity

Forced boiling of nonazeotropic immiscible mixture in a supercapillary microchannel array for ultra-high heat flux removal with chip junction temperature below 85℃

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Science China(Technological Sciences) 2024年第5期67卷 1364-1380页

作者： sun bo BAO YuChen TIAN Tong LI Ji School of Engineering Science University of Chinese Academy of SciencesBeijing100049China Laboratory of Advanced Thermal Management Technologies School of Engineering ScienceUniversity of Chinese Academy of SciencesBeijing100049China

In this study,a structure-optimized two-phase microchannel heat sink with sintered submicron nucleation sites was developed and *** copper-based microchannels had a rectangular cross-section with an equivalent hydraulic diameter of 222μ*** subcooled flow boiling characteristics were comprehensively compared between pure HFE-7100 and a non-azeotropic,immiscible binary mixture of HFE-7100 and water,considering heating areas of 1 and 5 cm^(2).The total heating power input to the test section were 100–1500 and 250–3000 W for a 1 and 5 cm^(2)heat source,respectively,with a flow rate ranging from 50 to150 L/*** to pure HFE-7100,the non-azeotropic immiscible binary mixture of HFE-7100/water in the sintered porous microchannels exhibited a much higher overall heat transfer coefficient and lower power *** maintain the junction temperature of a high power electronic chip below 85℃,the proposed supercapillary microchannel heat sink could effectively dissipate the heat flux of 1275 W/cm^(2)over 1 cm^(2)heat source and 500 W/cm^(2)over 5 cm^(2)heat *** addition,the volume ratio of the binary mixture strongly influence the two-phase flow heat transfer *** optimal volume ratio exist in terms of the thermal resistance–pumping power minimization(HFE-7100:water=2:8 is recommended in this study).The findings of this investigation on the flow boiling properties of non-azeotropic immiscible mixtures help fill a gap in the related field.

关键词： microchannel sintered powder coating submicron nucleation cavities nonazeotropic immiscible ultra-high heat flux

When smoke meets gut:deciphering the interactions between tobacco smoking and gut microbiota in disease development

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Science China(Life Sciences) 2024年第5期67卷 854-864页

作者： bo Chen guangyi Zeng Lulu sun Changtao Jiang Center of Basic Medical Research Institute of Medical Innovation and ResearchPeking University Third HospitalBeijing 100191China Department of Physiology and Pathophysiology School of Basic Medical SciencesState Key Laboratory of Vascular Homeostasis and RemodelingPeking UniversityBeijing 100191China Center for Obesity and Metabolic Disease Research School of Basic Medical SciencesPeking UniversityBeijing 100191China State Key Laboratory of Women’s Reproductive Health and Fertility Promotion Peking UniversityBeijing 100191China Department of Endocrinology and Metabolism Peking University Third HospitalBeijing 100191China

Tobacco smoking is a prevalent and detrimental habit practiced worldwide,increasing the risk of various diseases,including chronic obstructive pulmonary disease(COPD),cardiovascular disease,liver disease,and *** previous research has explored the detrimental health effects of tobacco smoking,recent studies suggest that gut microbiota dysbiosis may play a critical role in these *** tobacco smoke components,such as nicotine,are found in the gastrointestinal tract and interact with gut microbiota,leading to lasting impacts on host health and *** review delves into the ways tobacco smoking and its various constituents influence gut microbiota composition and *** also summarize recent advancements in understanding how tobacco smoking-induced gut microbiota dysbiosis affects host ***,this review introduces a novel perspective on how changes in gut microbiota following smoking cessation may contribute to withdrawal syndrome and the degree of health improvements in smokers.

关键词： tobacco smoking gut microbiota dysbiosis nicotine smoking cessation

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Experimental Investigation on Solution Regeneration Performance and Coefficients in Full-Open System for Heat and Water Recovery of Flue gas

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Journal of Thermal Science 2024年第3期33卷 1094-1108页

作者： WEI Hongyang HUANg Shifang MA Yuxin CHEN bo sun Li ZHANg Xiaosong School of Energy and Environment Southeast UniversityNanjing210096China MOE Engineering Research Center for Building Energy Equipment&Environment Southeast UniversityNanjing210096China Jiangsu Frontier Electric Technology Co. LtdNanjing211106China

The recovery of heat and water from low-grade flue gas is of considerable importance for energy conservation and environmental *** the full-open absorption heat pump shows promise as a means of achieving heat and water recovery,the lack of research on heat and mass transfer performance of open-type solution evaporation regeneration represents a significant impediment to its design and *** paper experimentally investigates the regeneration performance of an open-type spaying tower equipped with ceramic structured *** different regeneration modes are proposed,namely ambient air receiver mode and flue gas receiver mode,to utilize air or low-grade flue gas as a driving *** impact of different input parameters on the regeneration characteristics,including heat transfer capacity,water removal rate,thermal efficiency,and humidity effectiveness,are *** findings indicate that the enhancement of regeneration can be achieved through the increase of solution flow rate,solution temperature,and flue gas flow rate in both regeneration ***,high solution concentration and flue gas humidity ratio can weaken water removal rates and reduce thermal *** the regeneration of CaCl_(2)-H_(2)O with a concentration of55%,flue gas around 200℃with a humidity ratio below 44 g/kg can successfully drive the solution regeneration *** the solution concentration or flue gas humidity ratio continues to rise,additional energy is necessary for ***,the coupled heat and mass transfer coefficients are fitted,which can contribute to the design and optimization of the open-type regenerator.

关键词： heat and water recovery solution regeneration flue gas regeneration performance coefficient

Cluster-Based Massive Access for Massive MIMO Systems

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China Communications 2024年第1期21卷 24-33页

作者： Shiyu Liang Wei Chen Zhongwen sun Ao Chen bo Ai State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong UniversityBeijing 100091China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100091China Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong UniversityBeijing 100091China Key Laboratory of Railway Industry of Broadband Mobile Information Communications Beijing Jiaotong UniversityBeijing 100091China Beijing Engineering Research Center of High-speed Railway Broadband Mobile Communications Beijing Jiaotong UniversityBeijing 100091China School of Information Engineering Zhengzhou UniversityZhengzhou 450001China

Massive machine type communication aims to support the connection of massive devices,which is still an important scenario in *** this paper,a novel cluster-based massive access method is proposed for massive multiple input multiple output *** exploiting the angular domain characteristics,devices are separated into multiple clusters with a learned cluster-specific dictionary,which enhances the identification of active *** detected active devices whose data recovery fails,power domain nonorthogonal multiple access with successive interference cancellation is employed to recover their data via *** results show that the proposed scheme and algorithm achieve improved performance on active user detection and data recovery.

关键词： compressive sensing dictionary learning multiuser detection random access