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Fossil organic carbon w.athering:A nexus in global biogeochemical cycles

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Science China Earth Sciences 2024年第6期67卷 2068-2072页

作者： Gaojun LI gen KLI Department of Earth and Planetary Sciences Nanjing UniversityNanjing 210023China Department of Earth Science University of CaliforniaSanta Barbara CA 93106USA

The participation of life processes represents a fundamental feature of geochemical cycles on the planet *** of primary processes is that the carbon-based life utilizes photosynthesis to convert atmospheric CO_(2) int... 详细信息

关键词： w.athering Earth geochemical

Primordial black holes and curvature perturbations from false vacuum islands

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 58-72页

作者： Rong-gen Cai Yu-Shi Hao Shao-Jiang w.ng School of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Asia Pacific Center for Theoretical Physics Pohang 37673Republic of Korea

Recently,much attention has been focused on the false vacuum islands that are flooded by an expanding ocean of true-vacuum bubbles slightly later than most of the other parts of the *** delayed decay regions w.ll accumulate locally larger vacuum energy density by staying in the false vacuum longer than those already transited into the true vacuum.A false vacuum island w.th thus acquired density contrast of a super-horizon size w.ll evolve locally from radiation dominance to vacuum dominance,creating a local baby Universe that can be regarded effectively as a local closed *** such density contrasts of super-horizon sizes can ever grow.large enough to exceed the threshold of gravitational collapse,primordial black holes w.ll form similar to those collapsing curvature perturbations on super-horizon scales induced by small-scale enhancements during *** not,such density contrasts can still induce curvature perturbations potentially observable *** this paper,w. revisit and elaborate on the generations of primordial black holes and curvature perturbations from delayed-decayed false vacuum islands during asynchronous first-order phase transitions w.th fitting formulas convenient for future model-independent studies.

关键词： first-order phase transitions primordial black holes curvature perturbations

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Superior compound coatings prepared by low.temperature vanadium-nitrocarburizing duplex treatment

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Rare Metals 2024年第4期43卷 1828-1835页

作者： gen Jin Fang-Fang Xu Xun-Xun Hu Yue Xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings w.re prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low.temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions w.re systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as w.ll as the grow.h kinetics of the layer w.s also *** the duplex treatment,the w.ar and corrosion resistances of steel surface w.re significantly *** w.s found that the grow.h kinetics of compound layer obeyed the parabolic law.w.th the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Grow.h kinetics

Optimal Planning of Hybrid AC/DC Low.voltage Distribution Netw.rks Considering DC Conversion of Three-phase Four-w.re Low.voltage AC Systems

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Journal of Modern Pow.r Systems and Clean Energy 2024年第1期12卷 141-153页

作者： Bo Zhang Lu Zhang w.i Tang gen Li Chen w.ng the College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China the Electric Energy Group Department of Engineering TechnologyTechnical University of Denmark(DTU)2750 BallerupDenmark the Pow.r Distribution Technology Center State Grid Beijing Electric Power Research InstituteBeijing 100075China

The increasing integration of distributed household photovoltaics(PVs)and electric vehicles(EVs)may further ag gravate voltage violations and unbalance of low.voltage distribu tion netw.rks(LVDNs).DC distribution netw.rks can increase the accommodation of PVs and EVs and mitigate mutilple pow.er quality problems by the flexible pow.r regulation capability of voltage source *** paper proposes schemes to es tablish hybrid AC/DC LVDNs considering the conversion of the existing three-phase four-w.re low.voltage AC systems to DC op *** characteristics and DC conversion constraints of typical LVDNs are *** addition,converter configura tions for typical LVDNs are proposed based on the three-phase four-w.re characteristics and quantitative analysis of various DC ***,an optimal planning method of hybrid AC/DC LVDNs is proposed,w.ich is modeled as a bi-level programming model considering the annual investments and three-phase *** are conducted to verify the effectiveness of the proposed optimal planning *** ulation results show.that the proposed optimal planning method can increase the integration of PVs w.ile simultaneously reduc ing issues related to voltage violation and unbalance.

关键词： Optimal planning low.voltage distribution net w.rk three-phase unbalance DC conversion

N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow.g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao Zhang Xiaoyan Zhang Junjie Zhang Shen’gen Zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the tw. primary draw.acks of pure TiO_(2). w. combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow.g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped w.th 0.1w.% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, w.ich is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction betw.en N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared w.th those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathw.ys of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow.nanotube heterojunction photocatalysis

On the Specificity of Nanozymes: A Perspective

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Chinese Journal of Chemistry 2024年第13期42卷 1515-1522页

作者： gen w.i Shuje Liu Yung-Kang Peng Hui w.i Department of Biomedical Engineering College of Engineering and Applied SciencesNanjing National Laboratory of MicrostructuresJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjingJiangsu 21023China Department of Chemistry.City University of Hong Kong Hong Kong 999077Hong Kong SARChina State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringChemistry and Biomedicine Innovation Center(ChemBIC)Nanjing UniversityNanjingJiangsu 210023China NMPA Key Laboratory for Biomedical Optics HangzhouZhejiang 310018China

w. have compiled eight promising strategies for enhancing the specificity and selectivity of nanozymes,as depicted in the comprehensive summary *** exhibit intricate and sophisticated structures,including substrate channels and active sites,w.ich can inform the design of *** of these structural features and the application of facet engineering/doping techniques can significantly enhance the catalytic specificity of ***,the use of Molecularly Imprinted Polymers(MiPs)to coat nanozymes represents an effective approach to impart substrate ***,several straightforw.rd stopgap strategies have been devised to improve nanozyme specificity for analytical applications,such as the integration of biorecognition elements and nanozyme sensor arrays through surface modification.

关键词： Nanozymes Enzymes Catalytic activity Specificity Perspective

Activity regulation and applications of metal-organic framew.rk-based nanozymes

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Rare Metals 2024年第3期43卷 900-914页

作者： Ge Fang Shou-Xin Bao gen-Xiu Zhou Cui-Cui Ge State Key Laboratory of Radiation Medicine and Protection School of Radiation Medicine and ProtectionSchool for Radiological and Interdisciplinary Sciences(RAD-X)Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education InstitutionsSoochow UniversitySuzhou 215123China Suzhou Nanomicro Technology Co. LtdSuzhou 215000China

As a new.generation of artificial enzymes,nanozymes show.outstanding advantages such as high stability,low.cost,and facile synthesis,w.ich endow.them w.th promising applications in biomedical and environmental *** the various reported nanozymes,metal-organic framew.rks(MOFs)could mimic the active center of natural enzymes and provide a hydrophobic environment,w.ich makes MOFs attractive alternatives to natural *** to the highly structural diversity and tailorability of MOFs,rational design w.ll contribute to improve the activity of MOF-based nanozymes and promote their potential applications in both biomedical and environmental ***,a comprehensiye suminary of activity regulatory strategies of MOF-based nanozymes is urgently ***,w. summarized the activity regulatory strategies of MOFs w.th intrinsic enzyme-like activities via modulation of metal nodes,ligands,structures and *** the applications of MOF-based nanozymes in biosensing,hazardous degradation,antibacterial,and cancer therapy w.re also ***,the current challenges and future perspectives w.re discussed in *** is highly expected that this review.w.ll provide a better understanding on the rational design of novel high-performance MOF-based nanozymes.

关键词： Metal-organic framew.rks(MOF)-based nanozymes Activity regulation Biosensing Cancer therapy Hazardous degradation Antibacterial

Influences of shale microstructure on mechanical properties and bedding fractures distribution

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Petroleum Science 2024年第3期21卷 1944-1954页

作者： Ming-Zhe Gu Mao Sheng Shi-Zhong Cheng Fan-Hao Gong gen-Sheng Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing2249China College of Petroleum Engineering China University of Petroleum-BeijingBeijing102249China Shenyang Center of China Geological Survey ShenyangLiaoning110034China

The difference in microstructure leads to the diversity of shale mechanical properties and bedding fractures distribution *** this paper,the microstructure and mechanical properties of Longmaxi marine shale and Qingshankou continental shale w.re studied by X-ray diffractometer(XRD),field emission scanning electron microscope(FE-SEM)w.th mineral analysis system,and ***,the typical bedding layers area w.s properly stratified using Focused Ion Beam(FIB),and the effects of microstructure and mechanical properties on the distribution patterns of bedding fractures w.re *** results show.that the Longmaxi marine shale sample contains more clay mineral grains,w.ile the Qingshankou continental shale sample contains more hard brittle mineral grains such as *** Longmaxi marine shale sample,hard brittle minerals w.th grain sizes larger than 20μm is18.24%and those w.th grain sizes smaller than 20μm is 16.22%.For Qingshankou continental shale sample,hard brittle minerals w.th grain sizes larger than 20μm is 40.7%and those w.th grain sizes smaller than 20μm is 11.82%.In comparison to the Qingshankou continental shale sample,the Longmaxi marine shale sample has a low.r modulus,hardness,and *** shales are formed by alternating coarse-grained and fine-grained layers during *** average single-layer thickness of Longmaxi marine shale sample is greater than Qingshankou continental shale *** tw. types of shale have similar bedding fractures distribution patterns and fractures tend to occur in the transition zone from coarse-grained to fine-grained *** orientation of the fracture is usually parallel to the bedding plane and detour occurs in the presence of hard brittle *** fracture distribution density of the Longmaxi marine shale sample is low.r than that of the Qingshankou continental shale sample due to the strong heterogeneity of the Qingshankou continental *** current resea

关键词： Shale Nanoindentation Microstructure Mechanical property Fracture

Significant contribution of carbonyls to atmospheric oxidation capacity(AOC)during the w.nter haze pollution over North China Plain

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Journal of Environmental Sciences 2024年第5期139卷 377-388页

作者： Xue Yang gen Zhang Guang Pan Guolan Fan Houyong Zhang Xuan Ge Mingyue Du School of Municipal and Environmental Engineering Shandong Jianzhu UniversityJi’nan 250101China State Key Laboratory of Severe w.ather&Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological SciencesBeijing 100081China Shandong Jinan Ecological Environment Monitoring Center Ji’nan 250101China

Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in w.nter that w.re w.ll correlated to particulate matter,for w.ich the reason have not been clearly *** w. measured carbonyl compounds and other trace gasses together w.th PM_(2.5)over urban Jinan in North China Plain during the *** higher carbonyl concentrations(average:14.63±4.21 ppbv)w.re found during w.ntertime haze pollution,about one to three-times relative to those on nonhaze days,w.th slight difference in chemical composition except formaldehyde(HCHO).HCHO(3.68 ppbv),acetone(3.17 ppbv),and acetaldehyde(CH_3CHO)(2.83 ppbv)w.re the three most abundant species,accounting for~75% of the total carbonylson both haze and non-haze *** from observational-based model(OBM)w.th atmospheric oxidation capacity(AOC)indicated that AOC significantly increased w.th the increasing carbonyls during the w.nter haze *** photolysis have supplied key oxidants such as RO_(2) and HO_(2),and thereby enhancing the formation of fine particles and secondary organic aerosols,elucidating the observed haze-carbonyls *** variation w.th carbonyls exhibiting peak values at early-noon and night highlighted the combined contribution of both secondary formation and primary diesel-fuel sources.1-butene w.s further confirmed to be the major precursor for *** study confirms the great contribution of carbonyls to AOC,and also suggests that reducing the emissions of carbonyls w.uld be an effective w.y to mitigate haze pollution in urban area of the NCP region.

关键词： Carbonyls Haze Observation-based model Source apportionment Atmospheric oxidation capacity