Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,t...Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.展开更多
A recently published modeling approach for the penetration into adobe and previous approaches implicitly criticized are reviewed and discussed.This article contains a note on the paper titled“Ballistic model for the ...A recently published modeling approach for the penetration into adobe and previous approaches implicitly criticized are reviewed and discussed.This article contains a note on the paper titled“Ballistic model for the prediction of penetration depth and residual velocity in adobe:A new interpretation of the ballistic resistance of earthen masonry”(DOI:https://doi.org/10.1016/j.dt.2018.07.017).Reply to the Note from Li Piani et al is linked to this article.展开更多
Desalination is emerging as a promising alternative among various technologies to resolve water shortage. However, desalination requires a sufficient energy and cooling device and therefore poses limitations for its i...Desalination is emerging as a promising alternative among various technologies to resolve water shortage. However, desalination requires a sufficient energy and cooling device and therefore poses limitations for its installation and application. In particular, many countries suffering water deficits are economically underdeveloped and cannot afford the technology. As this technology, which changes seawater into freshwater, has little environmental impact, developed countries will need to assist less developed countries to introduce this technology as a humanitarian effort. This will help reduce the number of countries that have experienced difficulty with development.展开更多
A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition...A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.展开更多
Every year on 22 April, we have celebrated Earth Day and the beautiful planet we call home. Earth Day, established in 1970, has been used to highlight our planet’s environmental challenges and raise awareness of the ...Every year on 22 April, we have celebrated Earth Day and the beautiful planet we call home. Earth Day, established in 1970, has been used to highlight our planet’s environmental challenges and raise awareness of the importance of protecting our world for future generations [1]. To provide the protection of our planet, we should explain Earth’s environmental challenges to the best of our knowledge in frames of contemporary Geophysics. This paper gives a short overview of the developed Hypersphere World-Universe Model (WUM) and pay particular attention to the principal role of Dark Matter (DM) in the Earth’s life. In this manuscript, we discuss different aspects of the Earth: a condition of Young Earth before the Beginning of life on It;Internal Structure;“The 660-km Boundary” that we named Geomagma;Random Variations of Earth’s Rotational Speed on a daily basis;Origin of Moon;Expanding Earth;Internal Heating;Faint Young Sun paradox;Geocorona and Planetary Coronas;High-Energy Atmospheric Physics. WUM proposed principally different ways to solve the problems of Internal Heating, Origin of the Moon, and Faint Young Sun paradox based on DM core of the Earth. The Model revealed the fact that the Sun Activity causes the Geomagma Activity and, as a consequence, Random Variations of Earth’s Rotational Speed by the varying Sun’s magnetic field.展开更多
This paper presents experimental studies on a compacted expansive soil,from Nanyang,China for investigating the at-rest lateral earth pressureσL of expansive soils.The key studies include(i)relationships between the...This paper presents experimental studies on a compacted expansive soil,from Nanyang,China for investigating the at-rest lateral earth pressureσL of expansive soils.The key studies include(i)relationships between theσL and the vertical stressσV during soaking and consolidation,(ii)the influences of initial dry densityρd0 and moisture content w 0 on the vertical and lateral swelling pressures at no swelling strain(i.e.σV0 andσL0),and(iii)evolution of theσL during five long-term wetting-drying cycles.Experimental results demonstrated that the post-soakingσL-σV relationships are piecewise linear and their slopes in the passive state(σL>σV)and active state(σL<σV)are similar to that of the consolidationσL-σV relationships in the normal-and over-consolidated states,respectively.The soakingσL-σV relationships converge to the consolidationσL-σV relationships at a thresholdσV where the interparticle swelling is restrained.TheσL0 andσV0 increase monotonically withρd0;however,they show increasing-then-decreasing trends with the w 0.The extent of compaction-induced swelling anisotropy,which is evaluated byσL0/σV0,reduces with an increase in the compaction energy and molding water content.TheσL reduces over moisture cycles and the stress relaxation in theσL during soaking is observed.An approach was developed to predict the at-rest soakingσL-σV relationships,which requires conventional consolidation and shear strength properties and one measurement of theσL-σV relationships during soaking.The proposed approach was validated using the results of three different expansive soils available in the literature.展开更多
Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,wit...Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.展开更多
The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around...The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.展开更多
This study was to explore the functional mechanism of rare earth regulating soybean leaves and the characteristics and functions of differentially expressed proteins under the regulation of rare earth. In this study, ...This study was to explore the functional mechanism of rare earth regulating soybean leaves and the characteristics and functions of differentially expressed proteins under the regulation of rare earth. In this study, Dongnong 42 was used as material, and 30 mg·L^(-1) CeCl_(3) solution was sprayed on soybean leaves at the seedling stage. Tandem mass tag(TMT) quantitative proteomics technique and bioinformatics analysis were used to identify soybean leaf proteins. A total of 8 510 proteins were identified, and 127 differentially expressed proteins(DEPs) in response to rare earth cerium regulation were identified, among which 64 were upregulated and 63 were down-regulated. The gene ontology(GO) annotation indicated that DEPs were mainly involved in metabolic process, cellular process, response to stimulus, biological regulation, and response to a stimulus;DEPs in cell module categories were mainly involved in cells, cell part, organelle, membrane, membrane part, organelle par, and protein-containing complex;DEPs in molecular functional categories were mainly involved in catalytic activity, binding and antioxidant activity. Kyoto encyclopedia of genes and genomes(KEGG) pathway significantly enriched starch and sucrose metabolism, glycolysis/gluconeogenesis, galactose metabolism, pentose phosphate pathway, and MAPK signaling pathway-plant. These DEPs were mainly involved in photosynthesis, glucose metabolism and stress response. Forty-six differential protein interaction networks were identified by protein interaction network analysis. This experiment provided a reference for studies of the mechanism of rare earth cerium regulating soybean leaf function from the proteomic perspective.展开更多
The A_(2)B_(2)O_(7)-type rare earth zirconate compounds have been considered as promising candidates for thermal barrier coating(TBC) materials because of their low sintering rate,improved phase stability,and reduced ...The A_(2)B_(2)O_(7)-type rare earth zirconate compounds have been considered as promising candidates for thermal barrier coating(TBC) materials because of their low sintering rate,improved phase stability,and reduced thermal conductivity in contrast with the currently used yttria-partially stabilized zirconia (YSZ) in high operating temperature environments.This review summarizes the recent progress on rare earth zirconates for TBCs that insulate high-temperature gas from hot-section components in gas turbines.Based on the first principles,molecular dynamics,and new data-driven calculation approaches,doping and high-entropy strategies have now been adopted in advanced TBC materials design.In this paper,the solid-state heat transfer mechanism of TBCs is explained from two aspects,including heat conduction over the full operating temperature range and thermal radiation at medium and high temperature.This paper also provides new insights into design considerations of adaptive TBC materials,and the challenges and potential breakthroughs are further highlighted for extreme environmental applications.Strategies for improving thermophysical performance are proposed in two approaches:defect engineering and material compositing.展开更多
Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented ...Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented RH and to evaluate their influence on the behavior of raw earth for application in plaster. The influences of two types of RH are evaluated: granular rice husk (RHg) and powdered RH (RHp). The clay mainly consists of clay (40%), silt (22%), and sand (38.4%), with a small proportion of gravel (0.24%). Its liquidity limit is 40% and the plasticity index is 26.5%. The mixtures were designed using earth and each of the two rice husks at the volumetric content of 10%, 15% and 20% of the total volume mixed with water 36.5%, 38.5% and 40.3% and fermented for three weeks. Each fermented mixture was added to the soil to form the paste, and 40 × 40 × 160 mm<sup>3</sup> test speciments were made for characterization. The results generally show an improvement in the physico-mechanical properties and water resistance of the mortars containing fermented RH, with an optimal content between 10% and 15%. The powdered RH improved the performance of the mortar better than granular RH.展开更多
In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distanc...In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future.展开更多
It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals ex...It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.展开更多
Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid...Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid environments are not mastered. This article evaluates the influence of architectural and constructive modes of buildings made of CEB walls and concrete block walls, to optimize and compare their thermal comfort in the hot and dry tropical climate of Ouagadougou, Burkina Faso. Two identical pilot buildings whose envelopes are made of CEB and concrete blocks were monitored for this study. The thermal models of the pilot buildings were implemented in the SketchUp software using an extension of EnergyPlus. The models were empirically validated after calibration against measured thermal data from the buildings. The models were used to do a parametric analysis for optimization of the thermal performances by simulating plaster coatings on the exterior of walls, airtight openings and natural ventilation depending on external weather conditions. The results show that the CEB building displays 7016 hours of discomfort, equivalent to 80.1% of the time, and the concrete building displays 6948 hours of discomfort, equivalent to 79.3% of the time. The optimization by modifications reduced the discomfort to 2918 and 3125 hours respectively;i.e. equivalent to only 33.3% for the CEB building and 35.7% for the concrete building. More study should evaluate thermal optimizations in buildings in real time of usage such as residential buildings commonly used by the local middle class. The use of CEB as a construction material and passive means of improving thermal comfort is a suitable ecological and economical option to replace cementitious material.展开更多
基金funding support from National Natural Science Foundation of China(Grant No.52179109)Jiangsu Provincial Natural Science Foundation(Grant No.BK20230967)Open Research Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University(Grant No.KF2022-02).
文摘Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.
文摘A recently published modeling approach for the penetration into adobe and previous approaches implicitly criticized are reviewed and discussed.This article contains a note on the paper titled“Ballistic model for the prediction of penetration depth and residual velocity in adobe:A new interpretation of the ballistic resistance of earthen masonry”(DOI:https://doi.org/10.1016/j.dt.2018.07.017).Reply to the Note from Li Piani et al is linked to this article.
文摘Desalination is emerging as a promising alternative among various technologies to resolve water shortage. However, desalination requires a sufficient energy and cooling device and therefore poses limitations for its installation and application. In particular, many countries suffering water deficits are economically underdeveloped and cannot afford the technology. As this technology, which changes seawater into freshwater, has little environmental impact, developed countries will need to assist less developed countries to introduce this technology as a humanitarian effort. This will help reduce the number of countries that have experienced difficulty with development.
基金Funded by National Natural Science Foundation of China (No.52074218)。
文摘A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.
文摘Every year on 22 April, we have celebrated Earth Day and the beautiful planet we call home. Earth Day, established in 1970, has been used to highlight our planet’s environmental challenges and raise awareness of the importance of protecting our world for future generations [1]. To provide the protection of our planet, we should explain Earth’s environmental challenges to the best of our knowledge in frames of contemporary Geophysics. This paper gives a short overview of the developed Hypersphere World-Universe Model (WUM) and pay particular attention to the principal role of Dark Matter (DM) in the Earth’s life. In this manuscript, we discuss different aspects of the Earth: a condition of Young Earth before the Beginning of life on It;Internal Structure;“The 660-km Boundary” that we named Geomagma;Random Variations of Earth’s Rotational Speed on a daily basis;Origin of Moon;Expanding Earth;Internal Heating;Faint Young Sun paradox;Geocorona and Planetary Coronas;High-Energy Atmospheric Physics. WUM proposed principally different ways to solve the problems of Internal Heating, Origin of the Moon, and Faint Young Sun paradox based on DM core of the Earth. The Model revealed the fact that the Sun Activity causes the Geomagma Activity and, as a consequence, Random Variations of Earth’s Rotational Speed by the varying Sun’s magnetic field.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.52378365 and 52179109)Jiangsu Province Excellent Postdoctoral Program(Grant No.2023)China Scholarship Council-University of Ottawa Joint Scholarship.
文摘This paper presents experimental studies on a compacted expansive soil,from Nanyang,China for investigating the at-rest lateral earth pressureσL of expansive soils.The key studies include(i)relationships between theσL and the vertical stressσV during soaking and consolidation,(ii)the influences of initial dry densityρd0 and moisture content w 0 on the vertical and lateral swelling pressures at no swelling strain(i.e.σV0 andσL0),and(iii)evolution of theσL during five long-term wetting-drying cycles.Experimental results demonstrated that the post-soakingσL-σV relationships are piecewise linear and their slopes in the passive state(σL>σV)and active state(σL<σV)are similar to that of the consolidationσL-σV relationships in the normal-and over-consolidated states,respectively.The soakingσL-σV relationships converge to the consolidationσL-σV relationships at a thresholdσV where the interparticle swelling is restrained.TheσL0 andσV0 increase monotonically withρd0;however,they show increasing-then-decreasing trends with the w 0.The extent of compaction-induced swelling anisotropy,which is evaluated byσL0/σV0,reduces with an increase in the compaction energy and molding water content.TheσL reduces over moisture cycles and the stress relaxation in theσL during soaking is observed.An approach was developed to predict the at-rest soakingσL-σV relationships,which requires conventional consolidation and shear strength properties and one measurement of theσL-σV relationships during soaking.The proposed approach was validated using the results of three different expansive soils available in the literature.
基金supported by National Key Research and Development Program of China[2023YFB4605800]National Natural Science Foundation of China[51935014,52165043]+3 种基金JiangXi Provincial Natural Science Foundation of China[20224ACB204013,20224ACB214008]Jiangxi Provincial Cultivation Program for Academic and Technical Leaders of Major Subjects[20225BCJ23008]Anhui Provincial Natural Science Foundation[2308085ME171]The University Synergy Innovation Program of Anhui Province[GXXT-2023-025,GXXT-2023-026].
文摘Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.
文摘The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.
基金Supported by the National Natural Science Foundation of China(31471440)。
文摘This study was to explore the functional mechanism of rare earth regulating soybean leaves and the characteristics and functions of differentially expressed proteins under the regulation of rare earth. In this study, Dongnong 42 was used as material, and 30 mg·L^(-1) CeCl_(3) solution was sprayed on soybean leaves at the seedling stage. Tandem mass tag(TMT) quantitative proteomics technique and bioinformatics analysis were used to identify soybean leaf proteins. A total of 8 510 proteins were identified, and 127 differentially expressed proteins(DEPs) in response to rare earth cerium regulation were identified, among which 64 were upregulated and 63 were down-regulated. The gene ontology(GO) annotation indicated that DEPs were mainly involved in metabolic process, cellular process, response to stimulus, biological regulation, and response to a stimulus;DEPs in cell module categories were mainly involved in cells, cell part, organelle, membrane, membrane part, organelle par, and protein-containing complex;DEPs in molecular functional categories were mainly involved in catalytic activity, binding and antioxidant activity. Kyoto encyclopedia of genes and genomes(KEGG) pathway significantly enriched starch and sucrose metabolism, glycolysis/gluconeogenesis, galactose metabolism, pentose phosphate pathway, and MAPK signaling pathway-plant. These DEPs were mainly involved in photosynthesis, glucose metabolism and stress response. Forty-six differential protein interaction networks were identified by protein interaction network analysis. This experiment provided a reference for studies of the mechanism of rare earth cerium regulating soybean leaf function from the proteomic perspective.
基金the financial support from the National Natural Science Foundation of China(Nos.51572061,51621091,and 51321061)the Heilongjiang Touyan Team Program。
文摘The A_(2)B_(2)O_(7)-type rare earth zirconate compounds have been considered as promising candidates for thermal barrier coating(TBC) materials because of their low sintering rate,improved phase stability,and reduced thermal conductivity in contrast with the currently used yttria-partially stabilized zirconia (YSZ) in high operating temperature environments.This review summarizes the recent progress on rare earth zirconates for TBCs that insulate high-temperature gas from hot-section components in gas turbines.Based on the first principles,molecular dynamics,and new data-driven calculation approaches,doping and high-entropy strategies have now been adopted in advanced TBC materials design.In this paper,the solid-state heat transfer mechanism of TBCs is explained from two aspects,including heat conduction over the full operating temperature range and thermal radiation at medium and high temperature.This paper also provides new insights into design considerations of adaptive TBC materials,and the challenges and potential breakthroughs are further highlighted for extreme environmental applications.Strategies for improving thermophysical performance are proposed in two approaches:defect engineering and material compositing.
文摘Despite its low resistance to humidity, adobe remains the most widely used material for housing construction, particularly in developing countries. The present study aims to assess different modes of use of fermented RH and to evaluate their influence on the behavior of raw earth for application in plaster. The influences of two types of RH are evaluated: granular rice husk (RHg) and powdered RH (RHp). The clay mainly consists of clay (40%), silt (22%), and sand (38.4%), with a small proportion of gravel (0.24%). Its liquidity limit is 40% and the plasticity index is 26.5%. The mixtures were designed using earth and each of the two rice husks at the volumetric content of 10%, 15% and 20% of the total volume mixed with water 36.5%, 38.5% and 40.3% and fermented for three weeks. Each fermented mixture was added to the soil to form the paste, and 40 × 40 × 160 mm<sup>3</sup> test speciments were made for characterization. The results generally show an improvement in the physico-mechanical properties and water resistance of the mortars containing fermented RH, with an optimal content between 10% and 15%. The powdered RH improved the performance of the mortar better than granular RH.
基金This research was funded by the National Natural Science Foundation of China(Grant No.52174113)the Young Jinggang Scholars Award Program in Jiangxi Province,China(Grant No.QNJG2018051)the“Thousand Talents”of Jiangxi Province,China(Grant No.jxsq2019201043).
文摘In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the National Natural Science Foundation of China(Grant No.42174101,41974023)+1 种基金the Open Fund of Hubei Luojia Laboratory(Grant No.S22H640201)(Germany)The Offshore International Science and Technology Cooperation Center of Frontier Technology of Geodesy。
文摘It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.
文摘Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid environments are not mastered. This article evaluates the influence of architectural and constructive modes of buildings made of CEB walls and concrete block walls, to optimize and compare their thermal comfort in the hot and dry tropical climate of Ouagadougou, Burkina Faso. Two identical pilot buildings whose envelopes are made of CEB and concrete blocks were monitored for this study. The thermal models of the pilot buildings were implemented in the SketchUp software using an extension of EnergyPlus. The models were empirically validated after calibration against measured thermal data from the buildings. The models were used to do a parametric analysis for optimization of the thermal performances by simulating plaster coatings on the exterior of walls, airtight openings and natural ventilation depending on external weather conditions. The results show that the CEB building displays 7016 hours of discomfort, equivalent to 80.1% of the time, and the concrete building displays 6948 hours of discomfort, equivalent to 79.3% of the time. The optimization by modifications reduced the discomfort to 2918 and 3125 hours respectively;i.e. equivalent to only 33.3% for the CEB building and 35.7% for the concrete building. More study should evaluate thermal optimizations in buildings in real time of usage such as residential buildings commonly used by the local middle class. The use of CEB as a construction material and passive means of improving thermal comfort is a suitable ecological and economical option to replace cementitious material.