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Nitrogen addition promotes soil carbon accumulation globally

Science China Life Sciences 2025年第1期 284-293页

作者： Xuemei Yang Suhui Ma Erhan Huang Danhua Zhang Guoping Chen Jiangling Zhu Chengjun Ji Biao Zhu Lingli Liu Jingyun Fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking University Ministry of Education key laboratory for Transboundary Ecosecurity of Southwest China School of Ecology and Environmental ScienceYunnan University state key laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences

Soil is the largest carbon(C) reservoir in terrestrial ecosystems and plays a crucial role in regulating the global C cycle and climate *** nitrogen(N) deposition has been widely considered as a critical factor affecting soil organic carbon(SOC) storage, but its effect on SOC components with different stability remains unclear. Here, we analyzed extensive empirical data from 304 sites worldwide to investigate how SOC and its components respond to N addition. Our analysis showed that N addition led to a significant increase in bulk SOC(6.7%), with greater increases in croplands(10.6%) and forests(6.0%) compared to grasslands(2.1%). Regarding SOC components, N addition promoted the accumulation of plant-derived C(9.7%–28.5%) over microbial-derived C(0.2%), as well as labile(5.7%) over recalcitrant components(–1.2%), resulting in a shift towards increased accumulation of plant-derived labile C. Consistently, N addition led to a greater increase in particulate organic C(11.9%) than mineral-associated organic C(3.6%), suggesting that N addition promotes C accumulation across all pools, with more increase in unstable than stable pools. The responses of SOC and its components were best predicted by the N addition rate and net primary productivity. Overall, our findings suggest that N enrichment could promote the accumulation of plant-derived and non-mineral associated C and a subsequent decrease in the overall stability of soil C pool, which underscores the importance of considering the effects of N enrichment on SOC components for a better understanding of C dynamics in soils.

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Mesospheric tide comparisons at low latitudes observed by two collocated meteor radars

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Earth and Planetary Physics 2025年第1期9卷 54-68页

作者： Jian Li Wen Yi XiangHui Xue Jie Zeng HaiLun Ye JianYuan Wang JinSong Chen Na Li TingDi Chen Chinese Academy of Sciences(CAS)key laboratory of Geospace Environment Department of Geophysics and Planetary SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology Anhui Mengcheng Geophysics National Observation and Research StationUniversity of Science and Technology of ChinaHefei 230026China Hefei National laboratory University of Science and Technology of ChinaHefei 230026China Collaborative Innovation Center of astronautical Science and Technology Harbin 150001China National key laboratory of Electromagnetic Environment China Research Institute of Radiowave PropagationQingdao 266107China Yunnan Kunming Electromagnetic Environment National Observation and Research Station Qujing Kunming 655000China

Accurate knowledge of mesospheric winds and waves is essential for studying the dynamics and climate in the mesosphere and lower thermosphere(MLT)*** this study,we conduct a comparative analysis of the mesosphere tidal results obtained from two adjacent meteor radars at low latitudes in Kunming,China,from November 2013 to December *** two radars operate at different frequencies of 37.5 MHz and 53.1 MHz,***,overall good agreement is observed between the two radars in terms of horizontal winds and tide *** results show that the dominant tidal waves of the zonal and meridional winds are diurnal and semidiurnal ***,we conduct an exhaustive statistical analysis to compare the tidal amplitudes and vertical wavelengths recorded by the dual radar systems,which reveals a high degree of alignment in tidal *** investigation includes variances and covariances of tidal amplitudes,which demonstrate remarkable consistency across measurements from both *** finding highlights clear uniformity in the mesospheric tidal patterns observed at low latitudes by the two neighboring meteor *** of the comparative analysis specifically underscore the significant correlation in vertical wavelength measurements,validating the robustness of radar observations for tidal research.

关键词： mesosphere and lower thermosphere region meteor radar mesospheric winds tides

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Thermal Fluid-Solid Interaction Model and Experimental Validation for Hydrostatic Mechanical Face Seals

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 949-957页

作者： HUANG Weifeng LIAO Chuanjun LIU Xiangfeng SUO Shuangfu LIU Ying WANG Yuming state key laboratory of Tribology Tsinghua University Beijing Institute of astronautical Systems Engineering

Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power *** accurate models on the operating mechanism of the seals are needed to help improve their *** thermal fluid–solid interaction（TFSI）mechanism of the hydrostatic seal is investigated in this *** models of the flow field and seal assembly are *** on the mechanism for the continuity condition of the physical quantities at the fluid–solid interface,an on-line numerical TFSI model for the hydrostatic mechanical seal is proposed using an iterative coupling *** mesh technology is adopted to adapt to the changing boundary *** were performed on a test rig using a full-size test seal to obtain the leakage rate as a function of the differential *** effectiveness and accuracy of the TFSI model were verified by comparing the simulation results and experimental *** the TFSI model,the behavior of the seal is presented,including mechanical and thermal deformation,and the temperature *** influences of the rotating speed and differential pressure of the sealing device on the temperature field,which occur widely in the actual use of the seal,are *** research proposes an on-line and assembly-based TFSI model for hydrostatic mechanical face seals,and the model is validated by full-sized experiments.

关键词： mechanical face seal hydrostatic thermal fluid–solid interaction experiment

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Basical characteristics of fluid geologic process of interlayer oxidation zone sandstone-typeuranium deposit

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Science China Earth Sciences 2007年第z2期50卷 185-194页

作者： WU BoLin LIU ChiYang WANG JianQiang state key laboratory of Continental dynamics(Northwest University) Xi'an 710069 China State Key Laboratory of Continental Dynamics(Northwest University) Xi'an 710069 China State Key Laboratory of Continental Dynamics(Northwest University) Xi'an 710069 China

This paper reveals the physicochemical properties such as component, formulation, genesis, tem- perature, pH, Eh, salinity and pressure of all main alteration fluid of interlayer oxidation zone sand- stone-type uranium deposits after studying the geologic process and geochemistry of internal typical sandstone-type uranium deposits such as Shihongtan deposit in the Turpan-Hami basin, 512 deposit in the Yili basin, Dongsheng deposit in the Ordos basin. The composition of fluid can be divided into two parts based on the analysis of inclusion: one can be affirmed as atmospheric water with ordinary temperature epigenesist according to the character of hydrogen and oxygen isotope of inclusion, the other is natural gas containing gaseous hydrocarbon like CH4, and CO2 as well as a little H2S, CO, H2, N2 and so on, it always contains a small quantity of hydrocarbon liquid in petroliferous basins. The fluid property of oxidation alteration zone is always oxidation alkaline, and neutrality or weak acid-weak alkaline and reducibility during the metallizing process, but at secondary reduction or deoxidization zone it becomes strong reduction alkaline. Oxygenic groundwater in the fluid is the activate and mig- ratory medium of uranium element, but the gaseous hydrocarbon like CH4 as well as H2, H2S, CO from natural gas is the important sedimentary reducer of uranium mineral; the transformation of pH,Eh in fluid environment is the main reason for the formation of uranium metallization.

关键词： fluid, interlayer oxidation zone, uranium deposit, inclusion, isotope

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Analysis of the influence of micro satellite's development on space environment

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Journal of Beijing Institute of Technology 2016年第S2期25卷 185-189页

作者：魏峻赵导黄明 state key laboratory of Astronautic dynamics

In recent years,a large quantity of micro satellite has been launched into space,which makes the space environment of low Earth orbit(LEO) more *** reduce the negative influence bringing by micro satellite,the present situation of space environment and micro satellite are *** on the analysis of the relationship between micro satellite and space debris,especially the potential effect of micro satellite on monitoring and mitigation of space debris,some advices are presented.

关键词： micro satellite space environment space debris mitigation

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Theoretical approach to one-dimensional detonation instability

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Applied Mathematics and Mechanics(English Edition) 2016年第9期37卷 1231-1238页

作者： Chun WANG Gaoxiang XIANG Zonglin JIANG state key laboratory of High Temperature Gas dynamics Chinese Academy of Sciences

Detonation instability is a fundamental problem for understanding the microbehavior of a detonation front. With the theoretical approach of shock dynamics, detonation instability can be mathematically described as a second-order ordinary difference equation. A one-dimensional detonation wave can be modelled as a type of oscillators. There are two different physical mechanisms controlling the behaviors of a detonation. If the shock Mach number is smaller than the equilibrium Mach number, the fluid will reach the sonic speed before the end of the chemical reaction. Then, thermal chock occurs, and the leading shock becomes stronger. If the shock Mach number is larger than the equilib- rium Mach number, the fluid will be subsonic at the end of the chemical reaction. Then, the downstream rarefaction waves propagate upstream, and weaken the leading shock. The above two mechanisms are the basic recovery forces toward the equilibrium state for detonation sustenance and propagation. The detonation oscillator concept is helpful for understanding the oscillating and periodic behaviors of detonation waves. The shock dynamics theory of detonation instability gives a description of the feedback regime of the chemical reaction, which causes variations of the leading shock of the detonation. key words detonation wave, detonation instability, shock wave, chemical reaction

关键词： detonation wave detonation instability shock wave chemical reaction

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The adsorption and dissociation of multilayer CH_3OH on TiO_2(110)

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Science China Chemistry 2015年第4期58卷 614-619页

作者： Ruimin Wang Hongjun Fan state key laboratory of Molecular Reaction dynamics Dalian Institute of Chemical Physics

The adsorption and dissociation of CH3OH on TiO2 （110） were studied using density functional theory methods. Our results suggest that CH3OH molecules can adsorb up to 3/4 ML （1 ML=5.2× 10^14 molecules/cm2） coverage at five-coordinated titanium （Tisc） sites to form the first layer. In the second layer, the CH3OH is adsorbed at bridge-bonded oxygen, and from the third layer, the CH3OH molecules form a hydrogen-bonded network with each other. The theoretical results show that dissociation of multilayer adsorbed methanol to aldehyde occurs through a stepwise pathway, with easy O-H bond dissociation and rate-determining C-H bond dissociation. The dissociation barriers for 8 or 12 CH3OH molecules on TiO2 are higher than that for low coverage by 0.15-0.21 eV; this suggests that the dissociation of multilayer adsorbed CH3OH is harder.

关键词： adsorption dissociation multilayer CH3OH TiO2

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A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 555-577页

作者： Linlin Sun Zihui Wang Shukun Cui Ziquan Yan Weiping Hu Qingchun Meng state key laboratory of High-Speed Railway Track System China Academy of Railway Sciences Corporation LimitedBeijing100081China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed *** can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and *** researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry ***,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric *** this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to *** vertical dynamic forces in the time and frequency domains were compared under different running *** forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed ***,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is *** results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the *** ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

关键词： Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks

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Geochemical characteristics of Bikou volcanic group and Sr-Nd-Pb isotopic composition: Evidence for breakup event in the north margin of Yangtze plate, Jining era

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Science China Earth Sciences 2007年第z2期50卷 339-350页

作者： LI YongFei LAI ShaoCong QIN JiangFeng LIU Xin WANG Juan state key laboratory of Continental dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China

The geodynamic setting of the Bikou volcanic group is a critical question to trace the Precambrain tectonic framework and evolution for the Yangtze plate. This study has suggested that the Bikou volcanic group is composed of several residual oceanic crust units: MORB (mid-ocean ridge basalt), Alk-OIB (alkaline ocean island basalt) and Th-OIB (tholeiitic ocean island basalt) as well as subduction-related volcanic rocks. According to field observation, those distinct rocks occurred collectively in form of tectonic contact, implying that the Bikou volcanic group was an ophiolitic mélange. Coupled with geochronological data, a perished oceanic basin at the northern margin of the Yangtze block during Neoproterozoic was tested by this ophiolitic mélange. Meanwhile, the isogeochemical data suggest that the ocean occurred in the Southern Hemisphere identical to Indian, South Atlantic and South Pacific oceans in terms of their Dupal anomalies, and the original source of the rocks could be probably mixing by EMⅠand EMⅡ component caused by dehydration melting of subducting oceanic crust during subduction process. On the basis of geochemical characteristics of the studied rocks, the Bikou volcanic group could imply that a partial breakup event occurred in the northern margin of Yangtze plate during the Neoproterozoic era.

关键词： Bikou volcanic group, ophiolitic mélange, geochemistry, Dupal anomaly, Neoproterozoic, Yangtze plate

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Genesis of the Madang Cenozoic sodic alkaline basalt in the eastern margin of the Tibetan Plateau and its continental dynamic implications

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Science China Earth Sciences 2007年第z2期50卷 314-321页

作者： LAI ShaoCong ZHANG GuoWei LI YongFei QIN JiangFeng state key laboratory of Continental dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China

The Madang Cenozoic sodic alkaline basalt occurred in the eastern margin of the Tibetan Plateau, where is a key tectonic transform region of Tibet, North China, and Yangtze blocks. The basalts are characterized by the variation in SiO2=42%―51%, Na2O/K2O>4, belonging to the sodic alkaline basalt series. The rocks are enriched in Ba, Th, Nb, Ta, relative to a slight depletion in K, Rb in the trace and rare earth element (REE) spider diagrams that are similar to the typical oceanic island alkaline basalt. The Sr-Nd-Pb isotopic compositions suggest that they are derived from a mixed mantle reservoir. The western Qinling-Songpan tectonic region was controlled by Tibet, North China and Yangtze blocks since Cenozoic, therefore, the region was in the stage of the substance converge from the mantle to upper crust, producing a mixed mantle reservoir in the studied area. The Madang basalts occurred in the specific tectonic background, they result from partial melting of a mixed asthenospheric mantle reservoir in the western Qinling-Songpan tectonic node.

关键词： alkaline basalt, source region characteristics, continental dynamism, Cenozoic,eastern margin of Tibetan Plateau

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