Diamond negatively charged nitrogen-vacancy(NV-) centers provide an opportunity for the measurement of the Meissner effect on extremely small samples in a diamond anvil cell(DAC) due to their high sensitivity in detec...Diamond negatively charged nitrogen-vacancy(NV-) centers provide an opportunity for the measurement of the Meissner effect on extremely small samples in a diamond anvil cell(DAC) due to their high sensitivity in detecting the tiny change of magnetic field. We report on the variation of magnetic field distribution in a DAC as a sample transforms from normal to superconducting state by using finite element analysis. The results show that the magnetic flux density has the largest change on the sidewall of the sample, where NV-centers can detect the strongest signal variation of the magnetic field. In addition, we study the effect of magnetic coil placement on the magnetic field variation. It is found that the optimal position for the coil to generate the greatest change in magnetic field strength is at the place as close to the sample as possible.展开更多
Studies show that the sample thickness is an important parameter in investigating the thermal transport properties of materials under high-temperature and high-pressure(HTHP)in the diamond anvil cell(DAC)device.Howeve...Studies show that the sample thickness is an important parameter in investigating the thermal transport properties of materials under high-temperature and high-pressure(HTHP)in the diamond anvil cell(DAC)device.However,it is an enormous challenge to measure the sample thickness accurately in the DAC under severe working conditions.In conventional methods,the influence of diamond anvil deformation on the measuring accuracy is ignored.For a hightemperature anvil,the mechanical state of the diamond anvil becomes complex and is different from that under the static condition.At high temperature,the deformation of anvil and sample would be aggravated.In the present study,the finite volume method is applied to simulate the heat transfer mechanism of stable heating DAC through coupling three radiativeconductive heat transfer mechanisms in a high-pressure environment.When the temperature field of the main components is known in DAC,the thermal stress field can be analyzed numerically by the finite element method.The obtained results show that the deformation of anvil will lead to the obvious radial gradient distribution of the sample thickness.If the top and bottom surfaces of the sample are approximated to be flat,it will be fatal to the study of the heat transport properties of the material.Therefore,we study the temperature distribution and thermal conductivity of the sample in the DAC by thermal-solid coupling method under high pressure and stable heating condition.展开更多
Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an en...Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an enormous challenge to characterize the thermal and physical properties of materials using the diamond anvil cell(DAC)platform.In the present study,a steady-state method is used with a DAC and a combination of thermocouple temperature measurement and numerical analysis is performed to calculate the thermal conductivity of the material.To this end,temperature distributions in the DAC under high pressure are analyzed.We propose a three-dimensional radiative-conductive coupled heat transfer model to simulate the temperature field in the main components of the DAC and calculate in situ thermal conductivity under high-temperature and high-pressure conditions.The proposed model is based on the finite volume method.The obtained results show that heat radiation has a great impact on the temperature field of the DAC,so that ignoring the radiation effect leads to large errors in calculating the heat transport properties of materials.Furthermore,the feasibility of studying the thermal conductivity of different materials is discussed through a numerical model combined with locally measured temperature in the DAC.This article is expected to become a reference for accurate measurement of in situ thermal conductivity in DACs at high-temperature and high-pressure conditions.展开更多
In this work,we provide a comprehensive review on the formation,evolution,properties,and effects of supercritical geofluid.In Earth's interior,enhanced miscibility between H_(2)O and silicate by the addition of sp...In this work,we provide a comprehensive review on the formation,evolution,properties,and effects of supercritical geofluid.In Earth's interior,enhanced miscibility between H_(2)O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H_(2)O and silicate solute.The formation of supercritical geofluid in magmatic-hydrothermal systems,typified by pegmatite system,is governed by meltfluid critical curve.The formation of supercritical geofluid in metamorphic systems,typified by subducted slab,is governed by the second critical end point.Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths,but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth.A major presence of both H_(2)O and depolymerized structural units(monomers,dimers,etc.)endows supercritical geofluid with unique physical properties including low density,low elastic moduli,low viscosity,high diffusivity,and high electrical conductivity.Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements.The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts,and this could give an explanation of the oxidation of arc magmas.Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network.Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid.Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab,and can be linked with intermediate-focus earthquakes.Supercritical geofluid may have played a crucial role in the formation of pegmatites and associated ore deposits.展开更多
基金supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.11774126,11674404,and 51772125)
文摘Diamond negatively charged nitrogen-vacancy(NV-) centers provide an opportunity for the measurement of the Meissner effect on extremely small samples in a diamond anvil cell(DAC) due to their high sensitivity in detecting the tiny change of magnetic field. We report on the variation of magnetic field distribution in a DAC as a sample transforms from normal to superconducting state by using finite element analysis. The results show that the magnetic flux density has the largest change on the sidewall of the sample, where NV-centers can detect the strongest signal variation of the magnetic field. In addition, we study the effect of magnetic coil placement on the magnetic field variation. It is found that the optimal position for the coil to generate the greatest change in magnetic field strength is at the place as close to the sample as possible.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0702700)the National Natural Science Foundation of China(Grant Nos.11674404 and 11774126)。
文摘Studies show that the sample thickness is an important parameter in investigating the thermal transport properties of materials under high-temperature and high-pressure(HTHP)in the diamond anvil cell(DAC)device.However,it is an enormous challenge to measure the sample thickness accurately in the DAC under severe working conditions.In conventional methods,the influence of diamond anvil deformation on the measuring accuracy is ignored.For a hightemperature anvil,the mechanical state of the diamond anvil becomes complex and is different from that under the static condition.At high temperature,the deformation of anvil and sample would be aggravated.In the present study,the finite volume method is applied to simulate the heat transfer mechanism of stable heating DAC through coupling three radiativeconductive heat transfer mechanisms in a high-pressure environment.When the temperature field of the main components is known in DAC,the thermal stress field can be analyzed numerically by the finite element method.The obtained results show that the deformation of anvil will lead to the obvious radial gradient distribution of the sample thickness.If the top and bottom surfaces of the sample are approximated to be flat,it will be fatal to the study of the heat transport properties of the material.Therefore,we study the temperature distribution and thermal conductivity of the sample in the DAC by thermal-solid coupling method under high pressure and stable heating condition.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0702700)the National Natural Science Foundation of China(Grant Nos.11674404 and 11774126)。
文摘Investigating the thermal transport properties of materials is of great importance in the field of earth science and for the development of materials under extremely high temperatures and pressures.However,it is an enormous challenge to characterize the thermal and physical properties of materials using the diamond anvil cell(DAC)platform.In the present study,a steady-state method is used with a DAC and a combination of thermocouple temperature measurement and numerical analysis is performed to calculate the thermal conductivity of the material.To this end,temperature distributions in the DAC under high pressure are analyzed.We propose a three-dimensional radiative-conductive coupled heat transfer model to simulate the temperature field in the main components of the DAC and calculate in situ thermal conductivity under high-temperature and high-pressure conditions.The proposed model is based on the finite volume method.The obtained results show that heat radiation has a great impact on the temperature field of the DAC,so that ignoring the radiation effect leads to large errors in calculating the heat transport properties of materials.Furthermore,the feasibility of studying the thermal conductivity of different materials is discussed through a numerical model combined with locally measured temperature in the DAC.This article is expected to become a reference for accurate measurement of in situ thermal conductivity in DACs at high-temperature and high-pressure conditions.
基金supported by the National Key R&D Program of China(Grant No.2018YFA0702700)the National Natural Science Foundation of China(Grant Nos.42330301,42488101)the Fundamental Research Funds for the Central Universities of China(Grant No.WK3410000019)。
文摘In this work,we provide a comprehensive review on the formation,evolution,properties,and effects of supercritical geofluid.In Earth's interior,enhanced miscibility between H_(2)O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H_(2)O and silicate solute.The formation of supercritical geofluid in magmatic-hydrothermal systems,typified by pegmatite system,is governed by meltfluid critical curve.The formation of supercritical geofluid in metamorphic systems,typified by subducted slab,is governed by the second critical end point.Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths,but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth.A major presence of both H_(2)O and depolymerized structural units(monomers,dimers,etc.)endows supercritical geofluid with unique physical properties including low density,low elastic moduli,low viscosity,high diffusivity,and high electrical conductivity.Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements.The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts,and this could give an explanation of the oxidation of arc magmas.Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network.Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid.Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab,and can be linked with intermediate-focus earthquakes.Supercritical geofluid may have played a crucial role in the formation of pegmatites and associated ore deposits.
