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3D digital-image correlation insight into generalized relaxation behavior of sandstone under stress and pore pressure coupling

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Journal of Rock Mechanics and Geotechnical engineering 2024年第7期16卷 2516-2536页

作者： Cancan Chen Heping Xie Jiang Xu Seisuke Okubo Shoujian Peng Cunbao Li Minghui Li State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground engineering Shenzhen UniversityShenzhen518060China Guangdong Provincial Key Laboratory of Deep earth sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and GreenEnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China

The occurrence of geological hazards and the instability of geotechnical engineering structures are closely related to the time-dependent behavior of ***,the idealization boundary condition for constant stress in creep or constant strain in relaxation is not usually attained in natural geological ***,generalized relaxation tests that explore the simultaneous changes of stress and strain with time under different stress levels with constant pore-water pressure are conducted in this *** results show that in area Ⅰ,area Ⅱ,and area Ⅲ,the stress and strain both change synchronously with time and show similar evolutionary laws as the strain-time curve for creep or the stress-time curve for *** the applied stress level surpasses the δ_(ci) or δ_(cd) threshold,the variations in stress and strain and their respective rates of change exhibit a significant *** radial deformation and its rate of change exhibit greater sensitivity in response to stress *** apparent strain deforms homogeneously at the primary stage,and subsequently,gradually localizes due to the microcrack development at the secondary ***,interconnection of the microcracks causes the formation of a shear-localization zone at the tertiary *** strain-time responses inside and outside the localization zone are characterized by local strain accumulation and inelastic unloading during the secondary and tertiary stages,*** width of the shear-localization zone is found to range from 4.43 mm to 7.08 mm and increased with a longer *** electron microscopy(SEM)reveals a dominant coalescence of intergranular cracks on the fracture surface,and the degree of physiochemical deterioration caused by water-rock interaction is more severe under a longer *** brittle sandstone’s time-dependent deformation is essentially controlled by microcrack development during generalized relaxation,and its expectancy-life is dete

关键词： Generalized relaxation Stress level Direction coefficient Major-strain field Microcrack damage Stress threshold

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Valence-tailored copper-based nanoparticles for enhanced chemodynamic therapy through prolonged ROS generation and potentiated GSH depletion

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Nano Research 2024年第7期17卷 6342-6352页

作者： Xinyang Li Binbin Ding Jing Li Di Han Hao Chen Jia Tan Qi Meng Pan Zheng Ping’an Ma Jun Lin State Key Laboratory of Rare earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and engineering University of Science and Technology of ChinaHefei 230026China

Chemodynamic therapy(CDT),an inventive approach to cancer treatment,exploits innate chemical processes to trigger cell death through the generation of reactive oxygen species(ROS).While offering advantages over conventional treatments,the optimization of CDT efficacy presents challenges stemming from suboptimal catalytic efficiency and the counteractive ROS scavenging effect of intracellular glutathione(GSH).In this study,we aim to address this dual challenge by delving into the role of copper valence states in *** the unique attributes of copper-based nanoparticles,especially zero-valent copper nanoparticles(CuPd NPs),we aim to enhance the therapeutic potential of *** experiments reveal that zero-valent CuPd NPs outperform divalent copper nanoparticles(Ox-CuPd NPs)by displaying superior catalytic performance and sustaining ROS generation through a dual approach integrating peroxidase-like(POD-like)activity and Cu+***,zero-valent NPs exhibit enhanced GSH depletion compared to their divalent counterparts,thereby intensifying CDT and inducing ferroptosis,ultimately resulting in high-efficiency tumor growth *** findings reveal the impact of valences on CDT,providing novel insights for the optimization and design of CDT agents.

关键词： CuPd nanoparticle ferroptosis chemodynamic therapy valance tailoring tumor therapy

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All-inorganic nitrate electrolyte for high-performance lithium oxygen battery

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Nano Research 2024年第5期17卷 4163-4170页

作者： Dongyue Yang Jiayi Du Kai Chen Haoran Zhang Gang Huang Tong Liu Xinbo Zhang Hongjie Zhang State Key Laboratory of Rare earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and engineering University of Science and Technology of ChinaHefei 230026China

Lithium-oxygen(Li-O_(2))batteries have been regarded as an expectant successor for next-generation energy storage systems owing to their ultra-high theoretical energy ***,the comprehensive properties of the commonly utilized organic salt electrolyte are still unsatisfactory,not to mention their expensive prices,which seriously hinders the practical production and application of Li-O_(2) ***,we have proposed a low-cost all-inorganic nitrate electrolyte(LiNO_(3)-KNO_(3)-DMSO)for Li-O_(2) *** inorganic nitrate electrolyte exhibits higher ionic conductivity and a wider electrochemical stability window than the organic salt *** existence of K+can stabilize the O_(2)-intermediate,promoting the discharge process through the solution pathway with an enlarged *** at an ultra-low concentration of 0.01 M,the K+can still remain stable to promote the solution discharge process and also possess a new function of inhibiting the dendrite growth by electrostatic shielding,further enhancing the battery stability and contributing to the long cycle *** a result,in the 0.99 M LiNO_(3)-0.01 M KNO_(3)-DMSO electrolyte,the Li-O_(2) batteries exhibit prolonged cycling performance(108 cycles)and excellent rate performance(2 A·g^(-1)),significantly superior to the organic salt one.

关键词： Li-O_(2)batteries potassium ions inorganic nitrate electrolyte solution pathway mechanism

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Four decades of full-scale nitrous oxide emission inventory in China

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National Science Review 2024年第3期11卷 137-149页

作者： Minqi Liang Zheyan Zhou Peiyang Ren Han Xiao Xu-Ri Zhongmin Hu Shilong Piao Hanqin Tian Qing Tong Feng Zhou Jing Wei Wenping Yuan School of Atmospheric sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle Sun Yat-sen University State Key Laboratory of Tibetan Plateau earth System Resources and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province Hainan University Sino-French Institute for earth System Science College of Urban and Environmental SciencesPeking University Schiller Institute for Integrated Science and Society Department of Earth and Environmental Sciences Boston College Institute of Energy Environment and Economy Tsinghua University Southern Marine Science and engineering Guangdong Laboratory(Zhuhai)

China is among the top nitrous oxide（N2O）-emitting countries, but existing national inventories do not provide full-scale emissions including both natural and anthropogenic sources. We conducted a four-decade（1980–2020） of comprehensive quantification of Chinese N2O inventory using empirical emission factor method for anthropogenic sources and two up-to-date process-based models for natural sources. Total N2O emissions peaked at 2287.4（1774.8–2799.9） Gg N2O yr-1in 2018, and agriculture-developed regions, like the East, Northeast, and Central, were the top N2O-emitting regions. Agricultural N2O emissions have started to decrease after 2016 due to the decline of nitrogen fertilization applications, while, industrial and energetic sources have been dramatically increasing after 2005. N2O emissions from agriculture, industry,energy, and waste represented 49.3%, 26.4%, 17.5%, and 6.7% of the anthropogenic emissions in 2020,respectively, which revealed that it is imperative to prioritize N2O emission mitigation in agriculture,industry, and energy. Natural N2O sources, dominated by forests, have been steadily growing from 317.3（290.3–344.1） Gg N2O yr-1in 1980 to 376.2（335.5–407.2） Gg N2O yr-1in 2020. Our study produces a Full-scale Annual N2O dataset in China（FAN2020）, providing emergent counting to refine the current national N2O inventories.

关键词： nitrous oxide four decades anthropogenic sources natural sources

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Spatiotemporal variation of rainy season span and precipitation recorded by lacustrine laminated pollen in the Tibetan Plateau during the past two millennia

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Science China earth sciences 2024年第3期67卷 789-801页

作者： Anning CUI Houyuan LU Juzhi HOU Xingqi LIU Deke XU Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for earth Science Chinese Academy of SciencesBeijing 100029China College of earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China Group of Alpine Paleoecology and Human Adaptation State Key Laboratory of Tibetan Plateau Earth SystemResources and EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of sciences Beijing 100049China Capital Normal University College of Resource Environment and Tourism Beijing 100048China

The quantitative reconstruction of the length of the rainy season and precipitation on the Tibetan Plateau(TP) is crucial for revealing the spatiotemporal evolution of the Westerlies and Asian summer monsoon, as well as its ecological and environmental effects. Accurately determining the start and end times of the rainy season on the Plateau remains *** study determined the start and end times of the rainy season in different locations on the Plateau by identifying precipitation inflection points. We calculated the duration and precipitation amount of the rainy season and established a transfer function between the modern pollen assemblages and them. Then, we reconstructed the rainy season variations in Kusai Lake(northern TP) and Jiang Co(central TP) during the past two millennia. The results showed that, the rainy season precipitation in Kusai Lake recorded five periods of high precipitation: AD 580–680, 1000–1100, 1200–1450, 1550–1780, and 1920–present, corresponding to the stages with long rainy season. The rainy season precipitation sequence in Jiang Co recorded four periods of high precipitation: AD 80–500, 800–950, 1250–1450, and 1780–present, which is consistent with the long rainy season before AD 1000 but unclear afterward. Spatially, rainy season precipitation on the Plateau exhibited four patterns: “wet in both north and south” may be related to abnormally strong summer monsoons;“dry in both north and south” likely associated with weak Westerly wind and weak summer monsoon;“wet in the south and dry in the north” linked to strong summer monsoon and weak Westerly wind;and “dry in the south and wet in the north” connected to weak summer monsoon and strong Westerly wind. This study revealed the spatiotemporal evolution pattern of the rainy season onset and end, duration, and precipitation amount on the Plateau over the past two millennia. It provides natural background support for further understanding the coupling between Westerly wind and Asia

关键词： Tibetan Plateau Past two millennia Rainy season length Rainy season precipitation Quantitative reconstruction

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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： Gürel Cam Ali Günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

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Quaternary integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China earth sciences 2024年第4期67卷 1360-1394页

作者： Yong WANG Mianping ZHENG Yuan LING Shuyuan XIANG Zhaogang SHAO Kexin ZHANG Xue KE Xiao LIN Fang HAN Jian’en HAN Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Institute of Mineral Resources Chinese Academy of Geological SciencesBeijing 100037China Faculty of earth sciences China University of GeosciencesWuhan 430074China Chinese Academy of Geological sciences Beijing 100037China Institute of Geological Survey China University of GeosciencesWuhan 430074China School of earth sciences East China University of TechnologyNanchang 330013China Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China

The Quaternary strata on the Qinghai-Tibet Plateau contain rich information about the paleoclimate and environmental evolution,record the evolution process of the Quaternary regional tectonics,paleogeography,and geomorphology of the plateau,and are extremely important areas for studying the Quaternary geological events and regional environmental *** to a comprehensive analysis of the regional stratigraphic data and the development and evolution characteristics of the biota,based on the differences in the lithostratigraphic units,sedimentary characteristics,landforms,and drainage systems,the Quaternary strata on the Qinghai-Tibet Plateau and its surrounding areas are divided into five stratigraphic regions:the Tarim region,Loess Plateau region,Qinghai-Tibet Plateau region,Yunnan-Guizhou Plateau region,and India-Ganges *** Qinghai-Tibet Plateau stratigraphic region is divided into seven stratigraphic sub-regions:the West Kunlun-Karakorum,AltunQilian Mountains,Qaidam-Hehuang,East Kunlun-Bayan Har,Qiangtang,East Xizang-West Yunnan-West Sichuan,and Gangdise-Himalayan *** paper briefly describes the lithostratigraphic units of the seven stratigraphic sub-regions of the Qinghai-Tibet *** to the lithostratigraphic sequence and its sedimentary characteristics,stratigraphic contact relationship,formation age,and evolution of the biota in each stratigraphic sub-region,the Quaternary tectonic paleogeographic evolution of the Qinghai-Tibet Plateau is divided into four stages.(1)The inherited differential uplift stage since the Pliocene(2.6-1.8/1.5 Ma):the regional sedimentary differences were significant,and the stratigraphic distribution was limited,the alluvial-proluvial sandy conglomerate was widely developed along the piedmont,and fluvial and lacustrine deposits were developed in the low-lying areas between the mountains.(2)The mountain range flattening stage(1.8/1.5-1.2/0.8 Ma):the erosion unconformity surfaces around the pl

关键词： Quaternary stratigraphic sedimentary

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Effect of antioxidants on the efficiency of jet milling and the powder characteristics of Sm2Co17 permanent magnets

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Chinese Physics B 2024年第9期33卷 615-620页

作者： Da-Shuai Xu Lei Liu Jian-Hui Yuan Bo Zhou Chuang-Hui Dong Feng-Qing Wang Yong Ding Ying-Li Sun A-Ru Yan School of Materials Science and engineering Shanghai University of Engineering ScienceShanghai 201620China CISRI&NIMTE Joint Innovation Center for Rare earth Permanent Magnets CAS Key Laboratory of Magnetic Materials and DevicesZhejiang Province Key Laboratory of Magnetic Materials and Application TechnologyNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of Chinese Academy of sciences Beijing 100049China

This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet *** results show that adding antioxidants helps improve the dispersion among magnetic powders,leading to a 33.3%decrease in jet milling time and a 15.8%increase in magnet powder production ***,adding antioxidants enhances the oxidation resistance of the magnetic *** being stored in a constant temperature air environment at 25C for 48 h,the O content in the powder decreased by 33%compared to samples without *** in the magnet body,the O content decreased from 0.21 wt.%to 0.14 wt.%,which helps increase the effective Sm content and domain wall pinning uniformity in the *** magnetic properties were obtained in the magnet with added antioxidants:B_(r)=11.6 kGs,SF=79.6%,H_(cj)=16.8 kOe,and(BH)_(max)=32.5 MGOe.

关键词： antioxidant SmCo permanent magnet oxidation resistance grinding efficiency

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Insight of enriched basalts into the nature and evolution of mantle lithosphere beneath craton margins

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Science China earth sciences 2024年第10期67卷 3128-3142页

作者： Hong-Kun DAI Jianping ZHENG Qing XIONG Linlin HU Xiang ZHOU State Key Laboratory of Geological Processes and Mineral Resources School of Earth SciencesChina University of GeosciencesWuhan 430074China

Refractory lithospheric deep roots are the cornerstone for the prolonged stability of cratons and mantle xenoliths are normally the key targets for study on the evolution of such deep roots. In regions with few mantle xenoliths, the basalts enriched in radiogenic isotopic compositions due to marked lithospheric mantle contribution are crucial to unmask the lithospheric mantle evolution based on a comprehensive study involving petrology, geochemistry and thermodynamic modelling. Here, the Early Cretaceous basalts from the northwest North China Craton with few mantle xenoliths are taken as an example to show the significance of enriched basalts on the study of lithospheric mantle. These basalts are characterized by high silica and alkali contents(SiO_(2)=45.8–59.8 wt.%, K_(2)O+Na_(2)O=4.81–9.88 wt.%), arc-type trace-element patterns and enriched radiogenic isotope compositions(e.g., ε_(Nd)=-2.64–-12.88,^(87)Sr/^(86)Sr=0.7063–0.7093). The TiO_(2) and FeO(total) contents are higher than those of natural and experimental melts from refractory mantle peridotite but comparable to those of partial melts of fertile mantle *** high contents of fluid-loving elements(e.g., Rb and Ba) suggest source metasomatism by aqueous fluids. Combined with thermodynamic modelling and regional tectonic history, these enriched basalts likely record simultaneous decompression melting of asthenosphere and low-extent melting of thin and fertile lithospheric mantle fluxed by aqueous fluids from the subducted Paleo-Asian oceanic slab. The newly unmasked lithospheric mantle under the western NCC contrasts with the coeval thick and refractory one supporting the eastern NCC, and highlights that the craton destruction, especially the loss of its ancient refractory mantle root, should take place in a diachronous manner related to the craton-girded subduction episodes. Our study illustrates the potential of enriched basalts to recover the nature and evolution of mantle lithosphere beneath craton m

关键词： Enriched basalts Lithospheric mantle Northwest North China Craton Tectonic histories Early Cretaceous

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Water-soluble organic matter with various polarities in PM_(2.5) over Xi'an,China:Abundance,functional groups,and light absorption

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Particuology 2024年第1期84卷 281-289页

作者： Xueting Yang Shasha Huang Dan Li Hongmei Xu Yaling Zeng Liu Yang Diwei Wang Ningning Zhang Junji Cao Zhenxing Shen Department of Environmental Science and engineering Xi'an Jiaotong UniversityXi'an710049China School of Environmental Science and engineering Southern University of Science and TechnologyShenzhen518055China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710049China

Humic-like substances(HULIS)are a major component of brown carbon and consequently play a major role in climate *** this study,70 PM_(2.5) samples were collected from Xi'an in winter 2019 and summer *** HULIS(HULIS-n),acidic HULIS(HULIS-a),and high-polarity water-soluble organic compounds(HP-WSOC)were analyzed to determine their carbon concentrations and measure their ultraviolet-visible absorption and infrared *** the three components,HULIS-n had the highest carbon content in both winter(3.29±1.45μg m^(-3))and in summer(1.38±1.10μg m^(-3)).The semi-quantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter,whereas HULIS-n was rich in carboxylic acids in ***,HULJS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in *** results for specific ultraviolet absorbance(SUVA)and E_(250)/E_(365) revealed that HULIS had higher molecular weight and aromaticity in winter than in ***-n dominated in the total light absorption of HULIS+HP-WSOC in both winter(73.08%)and summer(48.57%).Overall,the results on the carbon content,optical properties,and functional groups of WSOCs with differing polarity can improve un-derstanding of environmental and climatic effects.

关键词： Humic-like substances(HULIS) Aromaticity Fourier-transform infrared(FTIR) spectroscopy Light absorbance

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