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In-situ Horizontal Extrusion Test of Herbaceous Root-Soil with Different Root Types

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Journal of earth Science 2024年第3期35卷 918-928页

作者： Fangcui Liu Shengwen Qi Shenglin Qi Xiaokun Hou Yanrong Li Guangming Luo Lei Xue Xueliang Wang Juanjuan Sun Songfeng Guo Bowen Zheng Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of sciences Beijing 100049China Innovation Academy for earth sciences Chinese Academy of SciencesBeijing 100029China china-pakistan joint research center on earth sciences CAS-HECIslamabad 45320Pakistan Government Affairs Service center of Beijing Municipal Water Affairs Bureau Beijing 100073China Department of earth sciences and Engineering Taiyuan University of TechnologyTaiyuan 030024China

The influence of different types of roots on the soil is complex and still remains *** in-situ extrusion tests were conducted on two types of root systems,namely fibrous and tap root system,for three plants,Eleusine indica,Potentilla anserine,and Artemisia argyi,according to the classification in Botany,and the thrust-displacement curves and failure patterns of different samples were analysed by comparison to fill the aforementioned *** reveal that the roots can reduce the characteristics of soil brittleness and enhance its capability to resist large deformation,and different root types contribute different effects to the strain-hardening behavior of the root-soil *** contribution of the fibrous root system to strength is limited,whilst the tap root system substantially enhances strength and *** of failure patterns show that fibrous and tap root systems affect soil solidification and surface cracking ***,the effect of the tap root system depends on the composition of lateral and tap roots:long and rich lateral roots are effective for resisting the creation of cracks,but thick tap roots with few and thin lateral roots may lead to several surface cracks.

关键词： root types fibrous root tap root in-situ horizontal extrusion test root-soil cracks slope protection.

Mobility and dynamic erosion process of granular flow:insights from numerical investigation using material point method

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Journal of Mountain Science 2024年第8期21卷 2713-2738页

作者： YU Fangwei SU Lijun LI Xinpo ZHAO Yu Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610299China University of Chinese Academy of sciences Beijing 100049China china-pakistan joint research center on earth sciences Islamabad 45320Pakistan center for Excellence in Tibetan Plateau earth sciences Chinese Academy of SciencesBeijing 100101China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China MOE Key Laboratory of Soft Soil and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310058China

In order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility and dynamic erosion process of granular flow subjected to the complex settings,i.e.,the aspect ratio,granular mass,friction and dilatancy resistance,gravity and presence of water.A set of power scaling laws were proposed to describe the final deposit characteristics of granular flow by the relations of the normalized run-out distance and the normalized final height of granular flow against the aspect ratio,being greatly affected by the complex geological settings,e.g.,granular mass,the friction and dilatancy resistance of granular soil,and presence of water in granular *** index of the coefficient of friction of granular soil was defined as a ratio of the target coefficient of friction over the initial coefficient of friction to quantify the scaling extent of friction change(i.e.,friction strengthening or weakening).There is a characteristic aspect ratio of granular column corresponding to the maximum mobility of granular flow with the minimum index of the apparent coefficient of *** index of the repose coefficient of friction of granular flow decreased gradually with the increase in aspect ratio because higher potential energy of granular column at a larger aspect ratio causes a larger kinetic energy of granular soil to weaken the friction of granular soil as a kind of velocity-related friction *** increase in granular mass reduces gradually the indexes of the apparent and repose coefficients of friction of granular soil to enhance the mobility of granular *** mobility of granular flow increases gradually with the decrease in friction angle or increase in dilatancy angle of granular ***,the increase of gravity accelerates granular flow but showing the same final deposit profile without any dependence on ***

关键词： Column collapse Granular flow Granular soil Material point method Mobility Numerical tests

A Study on the Assessment and Integration of Multi-Source Evapotranspiration Products over the Tibetan Plateau

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Advances in Atmospheric sciences 2024年第3期41卷 435-448页

作者： Ming CHENG Lei ZHONG Yaoming MA Han MA Yaoxin CHANG Peizhen LI Meilin CHENG Xian WANG Nan GE School of earth and Space sciences University of Science and Technology of ChinaHefei 230026China cas center for Excellence in Comparative Planetology Hefei 230026China Jiangsu Collaborative Innovation center for Climate Change Nanjing 210023China Frontiers Science center for Planetary Exploration and Emerging Technologies University of Science and Technology of ChinaHefei 230026China Land-Atmosphere Interaction and its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemResources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China College of Atmospheric Science Lanzhou UniversityLanzhou 730000China National Observation and research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu center of research and Education Chinese Academy of SciencesBeijing 100101China china-pakistan joint research center on earth sciences Chinese Academy of SciencesIslamabad 45320Pakistan

Evapotranspiration(ET)is a crucial variable in the terrestrial water,carbon,and energy *** present,a large number of multi source ET products *** to sparse observations,however,great challenges exist in the evaluation and integration of ET products in remote and complex areas such as the Tibetan Plateau(TP).In this paper,the applicability of the multiple collocation(MC)method over the TP is evaluated for the first time,and the uncertainty of multisource ET products(based on reanalysis,remote sensing,and land surface models)is further analyzed,which provides a theoretical basis for ET data *** results show that 1)ET uncertainties quantified via the MC method are lower in RS-based ET products(5.95 vs.7.06 mm month^(-1))than in LSM ET products(10.22 vs.17.97 mm month^(-1))and reanalysis ET estimates(7.27 vs.12.26 mm month-1).2)A multisource evapotranspiration(MET)dataset is generated at a monthly temporal scale with a spatial resolution of 0.25°across the TP during *** has better performance than any individual product.3)Based on the fusion product,the total ET amount over the TP and its patterns of spatiotemporal variability are clearly *** annual total ET over the entire TP is approximately 380.60 ***,an increasing trend of 1.59±0.85 mm yr^(-1)over the TP is shown during *** study provides a basis for future studies on water and energy cycles and water resource management over the TP and surrounding regions.

关键词： evapotranspiration data fusion multiple collocation the Tibetan Plateau

Neogene 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 1326-1359页

作者： Tao DENG Xiaomin FANG Qiang LI Shiqi WANG Feixiang WU Sukuan HOU Jiao MA Qigao JIANGZUO Danhui SUN Yan ZHENG Qinqin SHI Boyang SUN Lu LI Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China cas center for Excellence in Life and Paleoenvironment Beijing 100044China University of Chinese Academy of sciences Beijing 100049China cas center for Excellence in Tibetan Plateau earth sciences and Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China

The remarkable uplift of the Tibetan Plateau in the Neogene had great impacts on the climate and environment of East Asia and even the ***,establishment of the Neogene stratigraphic framework of the Tibetan Plateau is of great significance to research in various fields of *** on marine sediments,the international chronostratigraphic system of the Neogene is divided into six stages in the Miocene and two stages in the *** the beginning of the Cenozoic,the share of terrestrial strata on continents has increased *** the Neogene,it had far exceeded that of marine strata,and almost all deposits on the Tibetan Plateau and its surrounding areas were terrestrial *** china,the Miocene includes five stages and the Pliocene includes two *** for the Tunggurian of the Miocene,which has a lower boundary at 15 Ma,the other stages have the same paleomagnetic definitions and time intervals as the corresponding international marine *** fossils play a very important role in the division and correlation of Cenozoic terrestrial strata,and rodent,carnivore,proboscidean,perissodactyl and artiodactyl fossils are especially important in Neogene terrestrial *** are many basins with well-exposed strata and abundant mammalian fossils in the Tibetan *** lower boundary stratotype sections of the Neogene Xiejian and Bahean stages are located respectively in the Xining and Linxia basins,and there are precise paleomagnetic dates in coordination with mammalian *** lower boundary stratotypes of other stages can also be effectively determined in the Tibetan *** first appearing mammalian genera in East Asia also appeared in the Tibetan Plateau and its surrounding areas,especially in the Linxia Basin on the northeast margin and in the Siwaliks on the southwest *** them,Prodeinotherium first appeared at the bottom of the Miocene in the Siwaliks,and the earliest Hipparion of the Old

关键词： Tibetan Plateau Neogene Terrestrial stratum Mammalian fossil Paleomagnetism

Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

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Acta Geochimica 2024年第4期43卷 661-676页

作者： Jie Wang Yun Liu research center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China cas center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,Mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and earth-Moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

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Ion and electron motions in the outer electron diffusion region of collisionless magnetic reconnection

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earth and Planetary Physics 2024年第3期8卷 472-478页

作者： Cong Chang QuanMing Lu San Lu Kai Huang RongSheng Wang Deep Space Exploration Laboratory School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of sciences(cas)center for Excellence in Comparative Planetology CAS Key Laboratory of Geospace EnvironmentHefei 230026China Collaborative Innovation center of Astronautical Science and Technology Harbin 150001China

Two-dimensional particle-in-cell simulations are performed to study the coupling between ion and electron motions in collisionless magnetic *** electron diffusion region(EDR),where the electron motions are demagnetized,is found to have a two-layer structure:an inner EDR near the reconnection site and an outer EDR that is elongated to nearly 10 ion inertial lengths in the outflow *** the inner EDR,the speed of the electron outflow increases when the electrons move away from the X *** the outer EDR,the speed of the electron outflow first increases and then decreases until the electrons reach the boundary of the outer *** the boundary of the outer EDR,the magnetic field piles up and forms a depolarization *** the perspective of the fluid,a force analysis on the formation of electron and ion outflows has also been *** the X line,the electrons are accelerated by the reconnection electric field in the out-of-plane *** the electrons move away from the X line,we find that the Lorentz force converts the direction of the accelerated electrons to the x direction,forming an electron *** electric field forces and electron gradient forces tend to drag the electron *** acceleration along the x direction is caused by the Lorentz force,whereas the pressure gradient force tends to decelerate the ion *** these two terms are important,their effects on ions are almost *** Hall electric field force does positive work on ions and is not *** ions are continuously accelerated,and the ion and electron outflow velocities are almost the same near the depolarization front.

关键词： collisionless magnetic reconnection electron diffusion region force analysis particle-in-cell simulation

High-pressure minerals and new lunar mineral changesite-(Y) in Chang’e-5 regolith

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Matter and Radiation at Extremes 2024年第2期9卷 90-97页

作者： Jing Yang Wei Du center for Lunar and Planetary sciences Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of Sciences(CAS)Guiyang 550081China cas center for Excellence in Comparative Planetology Hefei 230026China

Forty-five years after the Apollo and Luna missions, china’s Chang’e-5 (CE-5) mission collected ∼1.73 kg of new lunar materials from one ofthe youngest basalt units on the Moon. The CE-5 lunar samples provide opportunities to address some key scientific questions related to theMoon, including the discovery of high-pressure silica polymorphs (seifertite and stishovite) and a new lunar mineral, changesite-(Y). Seifertitewas found to be coexist with stishovite in a silica fragment from CE-5 lunar regolith. This is the first confirmed seifertite in returned lunarsamples. Seifertite has two space group symmetries (Pnc2 and Pbcn) and formed from an α-cristobalite-like phase during “cold” compressionduring a shock event. The aftershock heating process changes some seifertite to stishovite. Thus, this silica fragment records different stagesof an impact process, and the peak shock pressure is estimated to be ∼11 to 40 GPa, which is much lower than the pressure condition forcoexistence of seifertite and stishovite on the phase diagram. Changesite-(Y), with ideal formula (Ca_(8)Y)◻Fe^(2+)(PO_(4))_(7) (where ◻ denotes avacancy) is the first new lunar mineral to be discovered in CE-5 regolith samples. This newly identified phosphate mineral is in the form ofcolumnar crystals and was found in CE-5 basalt fragments. It contains high concentrations of Y and rare earth elements (REE), reaching upto ∼14 wt. % (Y,REE)2O3. The occurrence of changesite-(Y) marks the late-stage fractional crystallization processes of CE-5 basalts combinedwith silicate liquid immiscibility. These new findings demonstrate the significance of studies on high-pressure minerals in lunar materials andthe special nature of lunar magmatic evolution.

关键词： evolution minerals basalt

Theoretical study of kinetic isotope eff ects for vacancy diff usion of impurity in solids

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Acta Geochimica 2024年第05期43卷 959-970页

作者： Yuxi Jing Xuefang Li Yun Liu research center for Planetary Science College of earth and Planetary sciences Chengdu University of Technology State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences cas center for Excellence in Comparative Planetology

Theoreticalstudiesofthediff usionalisotope eff ect in solids are still stuck in the 1960s and 1970s. With the development of high spatial resolution mass spectrometers, isotopic data of mineral grains are rapidly accumulated. To dig up information from these data, molecularlevel theoretical models are urgently needed. Based on the microscopic defi nition of the diff usion coe ffi cient (D), a new theoretical framework for calculating the diff usional isotope eff ect(DIE(v))(intermsofD*/D)forvacancy-mediated impurity diff usion in solids is provided based on statistical mechanics formalism. The newly derived equation shows that theDIE(v)can be easily calculated as long as the vibration frequencies of isotope-substituted solids are *** calculatedDIE(v)values of199 Au/195 Au and60 Co/57 Co during diff usion in Cu and Au metals are all within 1%of errors compared to the experimental data, which shows that this theoretical model is reasonable and precise.

关键词： Vacancy diff usion Diff usional isotope eff ect Statistical mechanics

Seasonal Characteristics of Forecasting Uncertainties in Surface PM_(2.5)Concentration Associated with Forecast Lead Time over the Beijing-Tianjin-Hebei Region

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Advances in Atmospheric sciences 2024年第5期41卷 801-816页

作者： Qiuyan DU Chun ZHAO Jiawang FENG Zining YANG Jiamin XU Jun GU Mingshuai ZHANG Mingyue XU Shengfu LIN Deep Space Exploration Laboratory/School of earth and Space sciences University of Science and Technology of ChinaHefei 230026China cas center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China

Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality ***,the particular impact of meteorological forecasting uncertainties on air quality forecasts specific to different seasons is still not well *** this study,a series of forecasts with different forecast lead times for January,April,July,and October of 2018 are conducted over the Beijing-Tianjin-Hebei(BTH)region and the impacts of meteorological forecasting uncertainties on surface PM_(2.5)concentration forecasts with each lead time are *** increased lead time,the forecasted PM_(2.5)concentrations significantly change and demonstrate obvious seasonal *** general,the forecasting uncertainties in monthly mean surface PM_(2.5)concentrations in the BTH region due to lead time are the largest(80%)in spring,followed by autumn(~50%),summer(~40%),and winter(20%).In winter,the forecasting uncertainties in total surface PM_(2.5)mass due to lead time are mainly due to the uncertainties in PBL heights and hence the PBL mixing of anthropogenic primary *** spring,the forecasting uncertainties are mainly from the impacts of lead time on lower-tropospheric northwesterly winds,thereby further enhancing the condensation production of anthropogenic secondary particles by the long-range transport of natural *** summer,the forecasting uncertainties result mainly from the decrease in dry and wet deposition rates,which are associated with the reduction of near-surface wind speed and precipitation *** autumn,the forecasting uncertainties arise mainly from the change in the transport of remote natural dust and anthropogenic particles,which is associated with changes in the large-scale circulation.

关键词： PM_(2.5) forecasting uncertainties forecast lead time meteorological fields Beijing-Tianjin-Hebei region