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Analyzing the spatiotemporal evolution and driving forces of gross ecosystem product in the upper reaches of the Chaobai River Basin

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 117-132页

作者： Jiacheng li Qi han liqiu Zhang li feng Guihuan liu Beijing Key Laboratory for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Center of Eco-compensation Chinese Academy of Environmental PlanningMinistry of Ecology of EnvironmentBeijing 100041China

The Chaobai River Basin,which is a crucial ecological barrier and primary water source area within the Beijing-Tianjin-Hebei region,possesses substantial ecological *** gross ecosystem product(GEP)in the Chaobai River Basin is a reflection of ecosystem conditions and quantifies nature’s contributions to humanity,which provides a basis for basin ecosystem service management and *** study investigated the spatiotemporal evolution of GEP in the upper Chaobai River Basin and explored the driving factors influencing GEP spatial *** patterns from 2005 to 2020 were analyzed,and GEP was calculated for 2005,2010,2015,and *** driving factors influencing GEP spatial differentiation were identified using the optimal parameter-based geographical detector(OPGD)*** key findings are as follows:(1)From 2005 to 2020,the main ecosystem types were forest,grassland,and *** areas experienced significant changes,and conversions mainly occurred among urban,water,grassland and agricultural ecosystems.(2)Temporally,the GEP in the basin increased from 2005 to 2020,with regulation services *** the county(district)scale,GEP exhibited a north-west-high and south-east-low pattern,showing spatial differences between per-unit-area GEP and county(district)GEP,while the spatial variations in per capita GEP and county(district)GEP were similar.(3)Differences in the spatial distribution of GEP were influenced by regional natural geographical and socioeconomic *** these factors,gross domestic product,population density,and land-use degree density contributed *** among different driving forces noticeably impacted GEP spatial *** findings underscore the necessity of incorporating factors such as population density and the intensity of land-use development into ecosystem management decision-making processes in the upper reaches of the Chaobai River *** policies

关键词： Ecosystem pattern Gross ecosystem product(GEP) Spatiotemporal evolution Optimal parameter-based geographical detector(OPGD) Chaobai River Basin

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Dynamic simulation analysis of molten salt reactor-coupled air-steam combined cycle power generation system

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Nuclear Science and Techniques 2024年第2期35卷 222-233页

作者： Jing-Lei Huang Guo-Bin Jia li-feng han Wen-Qian liu li Huang Zheng-han Yang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

A nonlinear dynamic simulation model based on coordinated control of speed and flow rate for the molten salt reactor and combined cycle systems is proposed here to ensure the coordination and stability between the molten salt reactor and power *** model considers the impact of thermal properties of fluid variation on accuracy and has been validated with *** study reveals the capability of the control system to compensate for anomalous situations and maintain shaft stability in the event of perturbations occurring in high-temperature molten salt tank outlet ***,the control system’s impact on the system’s dynamic characteristics under molten salt disturbance is also *** results reveal that after the disturbance occurs,the controlled system benefits from the action of the control,and the overshoot and disturbance amplitude are positively correlated,while the system power and frequency eventually return to the initial *** simulation model provides a basis for utilizing molten salt reactors for power generation and maintaining grid stability.

关键词： Molten salt reactor Combined cycle Dynamic characteristic Control

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Influence of powder oxidation on powder properties and formability in H13 hot-work steels processed by electron beam melting

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Journal of Iron and Steel Research(International) 2024年第4期31卷 924-932页

作者： Wei liu Yan Wang li-xiong han Ying-kang Wei Hui-ping Tang Shi-feng liu School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055ShaanxiChina School of Engineering Zhejiang University City CollegeHangzhou 310015ZhejiangChina

The oxygen content of metal powder is decisive for the recyclability of *** research on the effect of oxygen content on powder properties and material formability has practical significance for economical production with additive manufacturing while preventing the waste of ***,we deliberately oxidized the powder by baking at high temperature to increase the oxygen content in the powder and gave the calculation method of the oxygen content in the powder oxidation *** majority of oxygen element was found in the oxide particles in the powder and the oxide flm on the powder surface,which did affect the flowability of the *** is worth noting that the increase in the oxygen content does not change the phase of H13 steel,but it can promote the molten pool flow and obtain a smoother *** increase in the oxygen content in the powder is not the decisive factor for the formability and defects of the printed *** is the combined effect of the powder deformation,the increase in the oxygen content,and the impurity pollution after repeated use,which leads to the limitation of repeated utilization of the powder.

关键词： Additive manufacturing Electron beam melting H13 steel powder-Powder oxidation

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Effect of Ball Milling Time on Microstructure and Hydrogen Storage Properties of Nd5Mg41Ni Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1201-1214页

作者： Zeming Yuan Chenxu liu Xiaoming li Yongqi Sui Zhonggang han Tingting Zhai Dianchen feng Yanghuan Zhang Instrumental Analysis Center Inner Mongolia University of Science and TechnologyBaotou014010China Department of Functional Material Research Central Iron and Steel Research InstituteBeijing100081China

Mg-based alloys must be dehydrogenated at high pressure and temperatures, limiting their practical application. In this paper, Nd_(5)Mg_(41)Ni alloy was prepared by vacuum melting, and the as-cast alloy was ball milled for 5 h, 10 h, 15 h, and 20 h. The effect of ball milling time on the microstructure and hydrogen storage properties of the alloy was systematically studied. The alloy comprises Nd_(5)Mg_(41), NdMg_(12), NdMg_(3), and Mg_(2)Ni phases. The Nd_(5)Mg_(41)Ni alloy milling for 10 h can reach 95% of the saturated hydrogen absorption at 553 K by 40 s, and the alloy can desorb hydrogen only by 20 min. The dehydrogenation activation energy is only 99.9 kJ/mol H_(2). Ball milling makes the alloy produce many nanocrystalline and amorphous structures. The nano-grain boundary provides a channel for the diffusion of hydrogen atoms, and the high energy at the grain boundary provides energy for the phase deformation nucleus. Ball milling leads to the refinement of alloy particles and shortens the diffusion distance of hydrogen atoms to the interior of alloy particles. Defects such as twins and dislocations generated by milling provide energy for the phase deformation nucleus during the hydrogen absorption and desorption.

关键词： Hydrogen storage materials Magnesium-base alloy Ball milling Nanocrystal Kinetics

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Establishment of a three-dimensional particle library for graded crushed stone based on a new aggregate morphology characterization method

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 117-130页

作者： Haitao Ge Aimin sha Zhenqiang han School of Future Transportation Chang'an UniversityXi'an 710064China University of Strasbourg INSA StrasbourgCNRSICubeUMR 7357Strasbourg F-67000France School of Highway Chang'an UniversityXi'an 710064China Key Laboratory for Special Area Highway Engineering of Ministry of Education Chang'an UniversityXi'an 710064China

The morphology of graded crushed stone(GCS)particles has an essential influence on the performance of aggregate *** impact of particle shape is a comprehensive effect that cannot be considered separately,leading to difficulties in establishing the relationship between the mixture properties and the aggregate morphology by using laboratory *** discrete element method(DEM)is an effective way widely adopted to reconstruct the morphology of particles and simulate performance tests of granular ***,selecting limited particles characterizing a real particle-assembly for simulation is still a challenge in current research due to the inherent rich variability of particle *** this study,based on the acquisition of three-dimensional(3D)aggregate shapes by using laser scanning,ellipsoid index(EDI)translating the particle shape as a function of surface area,volume,and contour length is proposed to comprehensively evaluate aggregate ***,a particle library capable of characterizing aggregate morphology distribution is established based on the statistics of the corresponding morphological characteristics of particle *** model reliability is validated by carrying out a series of experimental and numerical penetration tests with nine different *** established particle library can be used to model aggregate mixtures and the proposed simulation framework is promising for optimizing the mixture gradation design numerically.

关键词： Particle library Discrete element method 3D laser scanning Coarse aggregate Morphology characterization Gradation design

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Phenotype-Directed DNA Nanomachine for in Situ Analysis of Stem Cell-like Subpopulation in Breast Cancer

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CCS Chemistry 2024年第4期6卷 1034-1046页

作者： Ya Cao Huiru Mao lingjun sha Qi liu Bing han Jing Zhao Genxi li Center for Molecular Recognition and Biosensing Shanghai Engineering Research Center of Organ RepairSchool of Life SciencesShanghai UniversityShanghai 200444 State Key Laboratory of Analytical Chemistry for life Science School of Life SciencesNanjing UniversityNanjing 210023

The cancer stem cell hypothesis provides a basis for prediction of the recurrence and risk of metastasis in breast ***,the unique expression pattern of stemness markers and the presence of nonstem-like cancer cells with varied phenotypes have brought great challenges to the characterization of breast cancer stem *** address these challenges,a phenotype-directed DNA nanomachine has been designed for high-accuracy labeling and in situ analysis of the stem cell-like subpopulation in breast *** key for the design is to use cell surfaceanchored inputs to activate the nanomachine,which undergoes different branch migration pathways such that the signal strand can only be brought onto the cancer cells having the stem cell-like *** sensitive determination and single-step isolation of the stem cell-like subpopulation were achieved by incorporating functional groups into the signal strand such that the nanomachine was successfully applied in a tumor-bearing mouse ***,the approach provides for a substantial improvement in capability for the analysis of the breast cancer stem cell-like subpopulation,and it is expected that the new approach will advance the use of DNA nanomachines in cancer-related studies.

关键词： breast cancer DNA nanomachine stem cell-like subpopulation electrochemical determination single-step isolation phenotypic analysis

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NHC-derived carbon-centered luminescent radicals with shortwavelength emission via suppression of Kasha's rule

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Science China Chemistry 2024年第8期67卷 2679-2685页

作者： Can Chen Xin li Xinhua Ouyang Ying-feng han Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education Xi’an Key Laboratory of Functional Supramolecular Structure and MaterialsCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an 710127China College of Material Engineering Fujian Agriculture and Forestry University Fuzhou 350108China

Luminescent organic radicals have garnered increasing attention owing to their versatile applications in sensing, imaging, and organic light-emitting diodes(OLEDs), attributed to their unique emission properties originating from the doublet spin ***, the natural narrow bandgap of organic free radicals typically limits their emission to the long-wavelength *** luminescent organic radicals with short-wavelength emission remains a significant challenge. Herein, a series of carbon-centered radicals with short-wavelength emission(383–476 nm) by combining N-heterocyclic carbenes with various polycyclic aromatic hydrocarbons(PAHs)(2-naphthyl, 2a~Ⅰ and 2b~Ⅰ;2-phenanthryl, 2a~Ⅱand 2b~Ⅱ;2-anthryl, 2a~Ⅲand 2b~Ⅲ;3-phenanthryl, 2a~Ⅳand 2b~Ⅳ). Theoretical calculations reveal that the introduction of PAHs significantly increases the ΔE_(D2-D1) in 2a^(Ⅰ–Ⅲ)and 2b^(Ⅰ–Ⅲ)compared to that in phenyl-derived radical congeners. Consequently, the internal transition from D2 to D1 is impeded, leading to a high yield of D2 emission and a suppressed Kasha's rule, thereby overcoming the limitations imposed by their narrow bandgap. For 2a~Ⅳ and 2b~Ⅳ, despite a moderately large ΔED2-D1value, the ΔED3-D1value exceeds 1 e V, indicating that their emission likely originates from the D3 state. Furthermore, we utilized 2a~Ⅲand 2b~Ⅲ as emissive materials in OLEDs,resulting in blue emissions with external quantum efficiencies of 7.5% and 6.5%, respectively.

关键词： N-heterocyclic carbenes luminescent organic molecules carbon-centered radicals short-wavelength emission

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Innovative construction of macroporous–mesoporous structured spherical alumina and its hydrothermal stability

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Particuology 2024年第7期90卷 429-435页

作者： Yufan Mo Chunli li Huiyu li Wei han He Wen Yinghong han Chunxia Che Yongjun feng State Key Laboratory of Chemical Resource Engineering Beijing Engineering Center for Hierarchical CatalystsCollege of ChemistryBeijing University of Chemical TechnologyBeijing100029China Lanzhou Petrochemical Research Center Petrochemical Research InstitutePetroChinaLanzhou730060China

The pore structure of spherical alumina supports is closely related to the dispersion of catalytically active components and the diffusion of *** excellent pore structure under strict reaction conditions is of utmost *** this work,sphericalγ-Al_(2)O_(3)support with a bimodal pore structure,composed of macropores and mesopores,was successfully synthesized using dodecane as the pore-forming agent through the oil–ammonia column-shaping *** morphology and internal pore structure of the alumina were found to be influenced by the amount of surfactant added and ultrasound treatment ***,when concentration of surfactant was 4‰and ultrasound voltage of 20 V was applied,the resultingγ-Al_(2)O_(3)-4‰-20 displayed a highly concentrated distribution of macropores with an average pore size of 100 nm,resulting in an impressive porosity of 69.21%.In contrast,the untreated sample ofγ-Al_(2)O_(3)-0-0 only exhibited a mesoporous distribution with a porosity of 54.03%.Moreover,after being subjected to a hydrothermal treatment in a high temperature(600°C)and high humidity(water vapor)environment for 120 h,theγ-Al_(2)O_(3)-4‰-20 sample maintained a high BET specific surface area of 170.9 m^(2)g^(−1)and mercury intrusion porosimetry specific surface area of 263.3 m^(2)g^(−1).

关键词： Spherical alumina supports Pore-forming agent Oil-ammonia column shaping method Hydrothermal treatment Hydrothermal stability

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Natural Products Improve Organ Microcirculation Dysfunction Following Ischemia/Reperfusion-and lipopolysaccharide-Induced Disturbances:Mechanistic and Therapeutic Views

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Engineering 2024年第7期38卷 77-99页

作者： Jingyan han Quan li Kai Sun Chunshui Pan Jian liu Ping Huang Juan feng Yanchen liu Gerald A.Meininger Department of Integration of Chinese and Western Medicine School of Basic Medical SciencesPeking UniversityBeijing 100191China Tasly Microcirculation Research Center Peking University Health Science CenterBeijing 100191China Key Laboratory of Stasis and Phlegm State Administration of Traditional Chinese Medicine of the People’s Republic of ChinaBeijing 100191China Beijing Laboratory of Integrative Microangiopathy Peking University Health Science CenterBeijing 100191China Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology University of MissouriColumbiaMO 65211USA

Microcirculatory disturbances are complex processes caused by many factors,including abnormal vasomotor responses,decreased blood flow velocity,vascular endothelial cell injury,altered leukocyte and endothelial cell interactions,plasma albumin leakage,microvascular hemorrhage,and *** disturbances involve multiple mechanisms and interactions among mechanisms that can include energy metabolism,the mitochondrial respiratory chain,oxidative stress,inflammatory factors,adhesion molecules,the cytoskeleton,vascular endothelial cells,caveolae,cell junctions,the vascular basement membrane,neutrophils,monocytes,and *** clinical practice,aside from drugs that target abnormal vasomotor responses and platelet adhesion,there continues to be a lack of multi-target drugs that can regulate the complex mechanistic links and interactions underlying microcirculatory *** products have demonstrated obvious positive therapeutic effects in treating ischemia/reperfusion(I/R)-and lipopolysaccharide(LPS)-induced microcirculatory *** recent years,numerous research papers on the improvement of microcirculatory function by natural products have been published in international *** 2008 and 2017,the first listed author of this review was invited to publish reviews in the journal of Pharmacology&Therapeutics on the improvement of microcirculatory disturbances and organ injury induced by I/R using Salvia miltiorrhiza ingredients and other natural components of compounded Chinese medicine,*** review systematically summarizes the effects,targets of action,and mechanisms of natural products regarding improving I/R-and LPSinduced microcirculatory disturbances and tissue *** on this summary,scientific proposals are suggested for the discovery of new drugs to improve microcirculatory disturbances in disease.

关键词： Ischemia/reperfusion lipopolysaccharide Natural products Leukocyte activation Hyperpermeability

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Structural,^(40)Ar/^(39)Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone:Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 32-49页

作者： feng Yipeng WANG Genhou WANG Shulai li Dian WANG Huan LU Yang liu han ZhanG Peilie Beijing Institute of Geology for Mineral Resources Co. Ltd.Beijing 100012China School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China College of Earth Sciences Chengdu University of TechnologyChengdu 610059China Rock Analysis Laboratory Regional Geology Survey Institute of Hebei ProvinceLangfangHebei 065099China Chengdu Center China Geology SurveyChengdu 610081China

The Jitang metamorphic complex is key to studying the tectonic evolution of the Northern Lancangjiang *** structural-lithological mapping,structural analysis and laboratory testing,the composition of the Jitang metamorphic complex was *** macro-and microstructural analyses of the ductile detachment shear zone(Guoxuepu ductile shear zone,2–4 km wide)between the metamorphic complex and the overlying sedimentary cap show that the shear sense of the ductile shear zones is *** presence of various deformation features and quartz C-axis electron backscatter diffraction(EBSD)fabric analysis suggests multiple deformation events occurring at different *** average stress is 25.68 MPa,with the strain rates(έ)ranging from 9.77×10^(−14)s^(−1)to 6.52×10^(−16)s^(−1).The finite strain of the Guoxuepu ductile shear zone indicates an elongated strain *** average kinematic vorticity of the Guoxuepu ductile shear zone is 0.88,implying that the shear zone is dominated by simple *** muscovite selected from the protomylonite samples in the Guoxuepu ductile shear zone yields a 40Ar-39Ar age of 60.09±0.38 *** is suggested that,coeval with the initial Indo–Eurasian collision,the development of strike-slip faults led to a weak and unstable crust,upwelling of lower crust magma,then induced the detachment of the Jitang metamorphic complex in the Eocene.

关键词： ^(40)Ar/^(39)Ar dating strain pattern vorticity EBSD Guoxuepu shear zone Jitang metamorphic complex

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