Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature ...Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI.Herein,we investigate the gap of formation behavior in both a half cell(graphite matches with lithium anode)and a full cell(graphite matches with NCM,short for LiNixCoyMn1-x-yO2)at different temperatures.We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer,the interface formed at room temperature owns the best ionic conductivity and stability.展开更多
Study of dolomite texture can contribute to understanding the process of dolomitization.This research reports textures and homogenization temperatures of dolomites from the Permian-Triassic strata in the Sichuan Basin...Study of dolomite texture can contribute to understanding the process of dolomitization.This research reports textures and homogenization temperatures of dolomites from the Permian-Triassic strata in the Sichuan Basin and the Lower Paleozoic strata in the Tarim Basin,which provided insights into relationships between dolomite textures and their formation temperatures.Our results are summarized as follows：1） dolomites with well-preserved texture indicate low dolomitization temperature.However,in certain diagenetic environments,the hydrothermal dolomitization may completely or partially preserve the original texture of dolomites.2） The formation temperatures of non-planar dolomites are always higher than those of planar dolomites.3） The formation temperatures of dolomite cements are generally higher than those of replacive dolomites.4） Although the formation temperatures of saddle dolomite cements have a wide range,they show higher values than those of the planar subhedral to euhedral dolomite cements.Thus,saddle dolomites could generally be an indicator of high precipitation temperature.5） The fluid Mg/Ca ratio is another element controlling dolomite morphology.Micritic dolomites,which precipitate from hypersaline fluids with a high Mg/Ca ratio in a subaerial environment could also have features of non-planar anhedral crystal shape because of rapid nucleation and crystallization during dolomitization.展开更多
Hydrates always are considered as a threat to petroleum industry due to the operational problems it can cause.These problems could result in reducing production performance or even production stoppage for a long time....Hydrates always are considered as a threat to petroleum industry due to the operational problems it can cause.These problems could result in reducing production performance or even production stoppage for a long time.In this paper, we were intended to develop a LSSVM algorithm for prognosticating hydrate formation temperature(HFT) in a wide range of natural gas mixtures. A total number of 279 experimental data points were extracted from open literature to develop the LSSVM. The input parameters were chosen based on the hydrate structure that each gas species form. The modeling resulted in a robust algorithm with the squared correlation coefficients(R^2) of 0.9918. Aside from the excellent statistical parameters of the model, comparing proposed LSSVM with some of conventional correlations showed its supremacy, particularly in the case of sour gases with high H_2S concentrations, where the model surpasses all correlations and existing thermodynamic models. For detection of the probable doubtful experimental data, and applicability of the model, the Leverage statistical approach was performed on the data sets. This algorithm showed that the proposed LSSVM model is statistically valid for HFT prediction and almost all the data points are in the applicability domain of the model.展开更多
Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz...Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature （HFT） under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.展开更多
Ammonium bisulfate(ABS)is a viscous compound produced by the escape NH_(3) in the NO reduction process and SO_(3) in the flue gas at a certain temperature,which can cause the ash corrosion of the air preheater in coal...Ammonium bisulfate(ABS)is a viscous compound produced by the escape NH_(3) in the NO reduction process and SO_(3) in the flue gas at a certain temperature,which can cause the ash corrosion of the air preheater in coal-fired power plants.Therefore,it is essential to study the formation temperature of ABS to prevent the deposition of ABS in air preheaters.In this paper,the SO_(3) reaction kinetic model is used to analyze the SO_(3) generation process from coal combustion to the selective catalytic reduction(SCR)exit stage,and the kinetic model of NO reduction is used to analyze the NH_(3) escape process.A prediction model for calculating the ABS formation temperature based on the S content in coal and NO reduction parameters of the SCR is proposed,solving the difficulty of measuring SO_(3) concentration and NH_(3) concentration in the previous calculation equation of ABS formation temperature.And the reliability of the model is verified by the actual data of the power plant.Then the influence of S content in coal,NH_(3)/NO_(x) molar ratio,different NO_(x) concentrations at SCR inlet,and NO removal efficiency on the formation temperature of ABS are analyzed.展开更多
The Hongtoushan Volcanogenic Massive Sulphide Deposit（VMSD）occurs in the Hunbei granite-greenstone terrane,Liaoning Province,NE China.Rocks in the mining area have been metamorphosed around 3.0-2.8 Ga to upper amphi...The Hongtoushan Volcanogenic Massive Sulphide Deposit（VMSD）occurs in the Hunbei granite-greenstone terrane,Liaoning Province,NE China.Rocks in the mining area have been metamorphosed around 3.0-2.8 Ga to upper amphibolite facies at temperatures between 600℃and 650℃.Cordierite-anthophyllite gneiss（CAG）in the Hongtoushan mining area,which occurs hundreds of meters below the ore horizon,corresponds to the metamorphosed semi-conformable alteration zone of the VMSD hydrothermal system,whereas the one immediately below the main ore layer represents the metamorphosed pipe-like alteration zone.Whole-rock oxygen isotope signatures were well preserved in both types of CAGs,although the mineral components have been entirely changed during regional metamorphism.Therefore,whole-rock oxygen isotopes can be used to estimate the formation temperature of both types of alteration zone.Calculations show that the semi-conformable and pipelike alteration zones for the Hongtoushan submarine hydrothermal system were formed at 290-360℃and 285-320°C,respectively,whereas estimates for the former were slightly higher than that of the latter,indicating that the semi-conformable alteration zone represents the deep part of the Hongtoushan seafloor hydrothermal system,while the pipe-like alteration zone represents the discharge conduits for metal-rich fluids,which is closer to the seafloor.展开更多
There are numerous correlations and thermodynamic models for predicting the natural gas hydrate formation condition but still the lack of a simple and unifying general model that addresses a broad ranges of gas mixtur...There are numerous correlations and thermodynamic models for predicting the natural gas hydrate formation condition but still the lack of a simple and unifying general model that addresses a broad ranges of gas mixture.This study was aimed to develop a user-friendly universal correlation based on hybrid group method of data handling(GMDH)for prediction of hydrate formation temperature of a wide range of natural gas mixtures including sweet and sour gas.To establish the hybrid GMDH,the total experimental data of 343 were obtained from open articles.The selection of input variables was based on the hydrate structure formed by each gas species.The modeling resulted in a strong algorithm since the squared correlation coefficient(R2)and root mean square error(RMSE)were 0.9721 and 1.2152,respectively.In comparison to some conventional correlation,this model represented not only the outstanding statistical parameters but also its absolute superiority over others.In particular,the result was encouraging for sour gases concentrated at H2S to the extent that the model outstrips all available thermodynamic models and correlations.Leverage statistical approach was applied on datasets to the discovery of the defected and doubtful experimental data and suitability of the model.According to this algorithm,approximately all the data points were in the proper range of the model and the proposed hybrid GMDH model was statistically reliable.展开更多
With the progress of science and technology, human beings explore the energy underground with thousands of meters. As a thermophysical parameter, initial formation temperature （IFT） plays an essential role in deep w...With the progress of science and technology, human beings explore the energy underground with thousands of meters. As a thermophysical parameter, initial formation temperature （IFT） plays an essential role in deep well engineering. However, it is not easy to predict the IFT accurately before drilling. This work uses a new method to analyze the effect factors of the underground temperature field, and assumes an artificial surface to eliminate the disturbance of the human errors and equipment errors on the surface temperature and thermal conductivity. Considering different distributions of the formation thermal conductivity and the rock radiogenic heat production, an optimized model was established. With this model, the paper predicted the bottom temperature of the main hole of the Chinese Continental Scientific Drilling （CCSD） as 132.80 ℃ at 4 725 m depth with 0.5% error. When the thermal conduction is dominant in the formation, this simple method can predict the IFT distribution effectively for deep well in the exploration stage. However, it is almost impossible to avoid aquifers in the formation of drilling deep well, an existing drillhole including groundwater is needed to predict for testing the model＇s accuracy.展开更多
The effect of annealing temperature on the formation of the PtSi phase. distribution of silicides and the surface morphologies of silicides films is investigated by XPS. AFM. It is shown that the phase sequences of t...The effect of annealing temperature on the formation of the PtSi phase. distribution of silicides and the surface morphologies of silicides films is investigated by XPS. AFM. It is shown that the phase sequences of the films change from Pt-Pt2Si-PtSi-Si to Pt+Pt2Si+PtSi-PtSi-Si or Pt+Pt2Si+PtSi-PtSi-st with an increase of annealing temperature and the reason for the formation of mixed layers is discussed.展开更多
The Qaidam Basin in the NE Tibetan Plateau has contributed the largest amount of potash in China.However,how the potash was formed has long been a subject of debate.Here we carried out a deep drilling
-In this paper the variations of the sea surface temperature anomalies (SSTA) in the Equatorial Eastern Pacific are analysed. The results show that there are two peaks in the spectrum. One is the low frequency oscilla...-In this paper the variations of the sea surface temperature anomalies (SSTA) in the Equatorial Eastern Pacific are analysed. The results show that there are two peaks in the spectrum. One is the low frequency oscillation with a period of 3 - 5 years, and the other is the quasi-biennial oscillation. The former shows a westward migration in the warm episode of SSTA and the latter has the opposite trend. The El Nino events will be formed while the two frquency bands are in phase in the warming stage of SSTA in the Equatorial Eastern Pacific展开更多
Supposing carbon contents of ferrite phases in pearlite precipitating from austenite in multicomponent steel at temperature T and in Fe-C ystem at T' are the same the pearlite formation temperature diference, can ...Supposing carbon contents of ferrite phases in pearlite precipitating from austenite in multicomponent steel at temperature T and in Fe-C ystem at T' are the same the pearlite formation temperature diference, can be calculated from the FeX phase diagrams and the equilibrium temperature Al. Using Tp and Fe-C binary thermodynamic model, the driving forces for phase transformation from austenite to pearlite in multicomponent steels have been successfully calculated. Through the combination of simplified Zener and Hillert's model for pearlite growth with Johnson-Mehl equation, using data from known TTT diagrams, the interfacial energy parameter and activation energy for pearlite formation can be determined and expressed as functions of chemical composition in steels by regression analysis. The calculated starting curves of pearlitic transformation in some commercial steels agree well with the experimental data.展开更多
Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from...Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from austenite in Fe-C binary system at temperature T'.is described as the temperature difference of proeutectiod ferrite formation, and can be calculated from the Fe-X diagrams and the equilibrium temperature A3. By introducing Tf and basing on the thermodynamic model for Fe-C binary alloy, the driving force for phase transformation from austenite to proeutectoid ferrite in multicomponent steels has been successfully calculated. Through the Johnson-Mehl equation and using the data hem known TTT diagrams, the relationship between the chemical composition and the intedecial edenly packeter as well as activation energy for proeutectoid ferrite formation can be calculated. The starting curves of proeutectoid ferritic transformation calculated in this way in some hypo-proeutectoid structural steels agree well with the erperimental data.展开更多
The uncertainty surrounding the thermal regimes of the ultra-deep strata in the Tarim and Sichuan basins,China,is unfavorable for further hydrocarbon exploration.This study summarizes and contrasts the present-day and...The uncertainty surrounding the thermal regimes of the ultra-deep strata in the Tarim and Sichuan basins,China,is unfavorable for further hydrocarbon exploration.This study summarizes and contrasts the present-day and paleo heat flow,geothermal gradient and deep formation temperatures of the Tarim and Sichuan basins.The average heat flow of the Tarim and Sichuan basins are 42.5±7.6 mW/m^(2)and 53.8±7.6 mW/m^(2),respectively,reflecting the characteristics of’cold’and’warm’basins.The geothermal gradient with unified depths of 0-5,000 m,0-6,000 m and 0-7,000 m in the Tarim Basin are 21.6±2.9℃/km,20.5±2.8℃/km and 19.6±2.8℃/km,respectively,while the geothermal gradient with unified depths of 0-5,000 m,0-6,000 m and 0-7,000 m in the Sichuan Basin are 21.9±2.3℃/km,22.1±2.5℃/km and23.3±2.4℃/km respectively.The differential change of the geothermal gradient between the Tarim and Sichuan basins with depth probably results from the rock thermal conductivity and heat production rate.The formation temperatures at depths of 6,000 m,7,000 m,8,000 m,9,000 m and 10,000 m in the Tarim Basin are 80℃-190℃,90℃-220℃,100℃-230℃,110℃-240℃and 120℃-250℃,respectively,while the formation temperatures at depths of 6,000 m,7,000 m,8,000 m and 9,000 m in the Sichuan Basin are 120℃-200℃,140℃-210℃,160℃-260℃and 180℃-280℃,respectively.The horizontal distribution pattern of the ultra-deep formation temperatures in the Tarim and Sichuan basins is mainly affected by the basement relief,fault activity and hydrothermal upwelling.The thermal modeling revealed that the paleo-heat flow in the interior of the Tarim Basin decreased since the early Cambrian with an early Permian abrupt peak,while that in the Sichuan Basin experienced three stages of steady state from Cambrian to early Permian,rapidly rising at the end of the early Permian and declining since the late Permian.The thermal regime of the Sichuan Basin was always higher than that of the Tarim Basin,which results in differential oil and gas generation and conservation in the ultra-deep ancient strata.This study not only promotes theoretical development in the exploration of ultra-deep geothermal fields,but also plays an important role in determining the maturation phase of the ultra-deep source rocks and the occurrence state of hydrocarbons in the Tarim and Sichuan basins.展开更多
The crystal structure of ludwigite from Vranovac ore deposit （Boranja Mt., Serbia） was refined using the X-ray powder diffraction （XRPD） Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It...The crystal structure of ludwigite from Vranovac ore deposit （Boranja Mt., Serbia） was refined using the X-ray powder diffraction （XRPD） Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of： a=9.2515（2） A; b=12.3109（2） A; c=3.03712 （7） A; and V=345.91（1） A3. The calculated distances and angles are mostly in good agreement with the Mg2＋-Fe2＋ substitutions across the M（1） and M（3） sites, as well as with the Fe3＋-AI3＋ replacement in the M（4） site. However, the mean observed M（2）-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3＋ content in the M（2） site. Such replacement was compensated by slight increase of the Fe2＋ content in the M（4） site, resulting in the （Mg1.4sFe2＋o.46Fe3＋o.osMno.o2）2.o1 （Fe3＋o.94Fe2＋0.04Al0.02）1.00B1.00Os composition. The formation temperature was estimated to be about 500- 600C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M（3） and M（4） sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.展开更多
Results of the investigation into the geothermal regime of the Fore-Yenisey sedimentary basin, formed during the collision and subsidence of the Kas-Turukhan microcontinent and the western margin of the Siberian crato...Results of the investigation into the geothermal regime of the Fore-Yenisey sedimentary basin, formed during the collision and subsidence of the Kas-Turukhan microcontinent and the western margin of the Siberian craton in the late Neoproterozoic and early Paleozoic are reported. It was established that the structural and geothermal conditions of the upper Precambrian–Paleozoic sections are similar to those in the western regions of the Siberian platform and are characterized by rather low geothermal gradients(12.5–25.5 ℃/km). In the western parts of the basin, formation temperatures in the uppermost pre-Jurassic sediments are 50℃–85℃, decreasing eastward to 30℃–55℃. For the first time, the detailed geothermal model of the basin sedimentary fill was developed. This model allows predictions of the geothermal conditions of Earth’s interior.展开更多
The gas hydrate formation in pipelines of industries and chemical plants can cause various operational damages and can increase economic risks.Hence,the knowledge of hydrate formation conditions has become a critical ...The gas hydrate formation in pipelines of industries and chemical plants can cause various operational damages and can increase economic risks.Hence,the knowledge of hydrate formation conditions has become a critical research study to overcome the problems arising from the formation of hydrates.In this study,we applied an algorithm to develop an LSSVM model to predict the formation temperature of natural gas hydrate for a comprehensive range of data points.Total 188 experimental data points were applied from the literature for the development of the LSSVM model.The input parameter was finalized based on the structure of hydrates by each gas species.The results obtained by the LSSVM model have good accuracy as compared with empirical correlations available in the literature.This model gave the squared correlation coefficient(R2),and root mean square error of 0.9901 and 0.59974,respectively.The composition of gases may affect the phase equilibrium condition of gas hydrates.The applied algorithm revealed that the developed LSSVM model could become a good alternative for calculating the formation temperature of hydrate for the range of all data sets.The results showed that the proposed LSSVM model could be applicable for the prediction of hydrate formation temperature for all data points.展开更多
基金supported by National Key Research and Development Program(2016YFA0202500)the National Natural Science Foundation of China(21776019)Beijing Natural Science Foundation(L182021)。
文摘Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase(SEI)covered on the graphite anode determines the service life of a battery.The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI.Herein,we investigate the gap of formation behavior in both a half cell(graphite matches with lithium anode)and a full cell(graphite matches with NCM,short for LiNixCoyMn1-x-yO2)at different temperatures.We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer,the interface formed at room temperature owns the best ionic conductivity and stability.
基金supported by the National Natural Science Foundation(Nos.41172099,41272130)
文摘Study of dolomite texture can contribute to understanding the process of dolomitization.This research reports textures and homogenization temperatures of dolomites from the Permian-Triassic strata in the Sichuan Basin and the Lower Paleozoic strata in the Tarim Basin,which provided insights into relationships between dolomite textures and their formation temperatures.Our results are summarized as follows：1） dolomites with well-preserved texture indicate low dolomitization temperature.However,in certain diagenetic environments,the hydrothermal dolomitization may completely or partially preserve the original texture of dolomites.2） The formation temperatures of non-planar dolomites are always higher than those of planar dolomites.3） The formation temperatures of dolomite cements are generally higher than those of replacive dolomites.4） Although the formation temperatures of saddle dolomite cements have a wide range,they show higher values than those of the planar subhedral to euhedral dolomite cements.Thus,saddle dolomites could generally be an indicator of high precipitation temperature.5） The fluid Mg/Ca ratio is another element controlling dolomite morphology.Micritic dolomites,which precipitate from hypersaline fluids with a high Mg/Ca ratio in a subaerial environment could also have features of non-planar anhedral crystal shape because of rapid nucleation and crystallization during dolomitization.
文摘Hydrates always are considered as a threat to petroleum industry due to the operational problems it can cause.These problems could result in reducing production performance or even production stoppage for a long time.In this paper, we were intended to develop a LSSVM algorithm for prognosticating hydrate formation temperature(HFT) in a wide range of natural gas mixtures. A total number of 279 experimental data points were extracted from open literature to develop the LSSVM. The input parameters were chosen based on the hydrate structure that each gas species form. The modeling resulted in a robust algorithm with the squared correlation coefficients(R^2) of 0.9918. Aside from the excellent statistical parameters of the model, comparing proposed LSSVM with some of conventional correlations showed its supremacy, particularly in the case of sour gases with high H_2S concentrations, where the model surpasses all correlations and existing thermodynamic models. For detection of the probable doubtful experimental data, and applicability of the model, the Leverage statistical approach was performed on the data sets. This algorithm showed that the proposed LSSVM model is statistically valid for HFT prediction and almost all the data points are in the applicability domain of the model.
文摘Production,processing and transportation of natural gases can be significantly affected by clathrate hydrates.Knowing the gas analysis is crucial to predict the right conditions for hydrate formation.Nevertheless,Katz gas gravity method can be used for initial estimation of hydrate formation temperature （HFT） under the circumstances of indeterminate gas composition.So far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and Vuthaluru.The main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity chart.By reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.
基金the Key Research and Development Plan of Shandong Province (2019GSF109004)Natural Science Foundation of Shandong Province (ZR2020ME190) for funding and supporting this work
文摘Ammonium bisulfate(ABS)is a viscous compound produced by the escape NH_(3) in the NO reduction process and SO_(3) in the flue gas at a certain temperature,which can cause the ash corrosion of the air preheater in coal-fired power plants.Therefore,it is essential to study the formation temperature of ABS to prevent the deposition of ABS in air preheaters.In this paper,the SO_(3) reaction kinetic model is used to analyze the SO_(3) generation process from coal combustion to the selective catalytic reduction(SCR)exit stage,and the kinetic model of NO reduction is used to analyze the NH_(3) escape process.A prediction model for calculating the ABS formation temperature based on the S content in coal and NO reduction parameters of the SCR is proposed,solving the difficulty of measuring SO_(3) concentration and NH_(3) concentration in the previous calculation equation of ABS formation temperature.And the reliability of the model is verified by the actual data of the power plant.Then the influence of S content in coal,NH_(3)/NO_(x) molar ratio,different NO_(x) concentrations at SCR inlet,and NO removal efficiency on the formation temperature of ABS are analyzed.
基金supported financially by the National Basic Research Program of the People's Republic of China (2006CB403501)the National Natural Science Foundation of China(Nos 40872050,40872064)
文摘The Hongtoushan Volcanogenic Massive Sulphide Deposit（VMSD）occurs in the Hunbei granite-greenstone terrane,Liaoning Province,NE China.Rocks in the mining area have been metamorphosed around 3.0-2.8 Ga to upper amphibolite facies at temperatures between 600℃and 650℃.Cordierite-anthophyllite gneiss（CAG）in the Hongtoushan mining area,which occurs hundreds of meters below the ore horizon,corresponds to the metamorphosed semi-conformable alteration zone of the VMSD hydrothermal system,whereas the one immediately below the main ore layer represents the metamorphosed pipe-like alteration zone.Whole-rock oxygen isotope signatures were well preserved in both types of CAGs,although the mineral components have been entirely changed during regional metamorphism.Therefore,whole-rock oxygen isotopes can be used to estimate the formation temperature of both types of alteration zone.Calculations show that the semi-conformable and pipelike alteration zones for the Hongtoushan submarine hydrothermal system were formed at 290-360℃and 285-320°C,respectively,whereas estimates for the former were slightly higher than that of the latter,indicating that the semi-conformable alteration zone represents the deep part of the Hongtoushan seafloor hydrothermal system,while the pipe-like alteration zone represents the discharge conduits for metal-rich fluids,which is closer to the seafloor.
文摘There are numerous correlations and thermodynamic models for predicting the natural gas hydrate formation condition but still the lack of a simple and unifying general model that addresses a broad ranges of gas mixture.This study was aimed to develop a user-friendly universal correlation based on hybrid group method of data handling(GMDH)for prediction of hydrate formation temperature of a wide range of natural gas mixtures including sweet and sour gas.To establish the hybrid GMDH,the total experimental data of 343 were obtained from open articles.The selection of input variables was based on the hydrate structure formed by each gas species.The modeling resulted in a strong algorithm since the squared correlation coefficient(R2)and root mean square error(RMSE)were 0.9721 and 1.2152,respectively.In comparison to some conventional correlation,this model represented not only the outstanding statistical parameters but also its absolute superiority over others.In particular,the result was encouraging for sour gases concentrated at H2S to the extent that the model outstrips all available thermodynamic models and correlations.Leverage statistical approach was applied on datasets to the discovery of the defected and doubtful experimental data and suitability of the model.According to this algorithm,approximately all the data points were in the proper range of the model and the proposed hybrid GMDH model was statistically reliable.
文摘With the progress of science and technology, human beings explore the energy underground with thousands of meters. As a thermophysical parameter, initial formation temperature （IFT） plays an essential role in deep well engineering. However, it is not easy to predict the IFT accurately before drilling. This work uses a new method to analyze the effect factors of the underground temperature field, and assumes an artificial surface to eliminate the disturbance of the human errors and equipment errors on the surface temperature and thermal conductivity. Considering different distributions of the formation thermal conductivity and the rock radiogenic heat production, an optimized model was established. With this model, the paper predicted the bottom temperature of the main hole of the Chinese Continental Scientific Drilling （CCSD） as 132.80 ℃ at 4 725 m depth with 0.5% error. When the thermal conduction is dominant in the formation, this simple method can predict the IFT distribution effectively for deep well in the exploration stage. However, it is almost impossible to avoid aquifers in the formation of drilling deep well, an existing drillhole including groundwater is needed to predict for testing the model＇s accuracy.
文摘The effect of annealing temperature on the formation of the PtSi phase. distribution of silicides and the surface morphologies of silicides films is investigated by XPS. AFM. It is shown that the phase sequences of the films change from Pt-Pt2Si-PtSi-Si to Pt+Pt2Si+PtSi-PtSi-Si or Pt+Pt2Si+PtSi-PtSi-st with an increase of annealing temperature and the reason for the formation of mixed layers is discussed.
文摘The Qaidam Basin in the NE Tibetan Plateau has contributed the largest amount of potash in China.However,how the potash was formed has long been a subject of debate.Here we carried out a deep drilling
文摘-In this paper the variations of the sea surface temperature anomalies (SSTA) in the Equatorial Eastern Pacific are analysed. The results show that there are two peaks in the spectrum. One is the low frequency oscillation with a period of 3 - 5 years, and the other is the quasi-biennial oscillation. The former shows a westward migration in the warm episode of SSTA and the latter has the opposite trend. The El Nino events will be formed while the two frquency bands are in phase in the warming stage of SSTA in the Equatorial Eastern Pacific
文摘Supposing carbon contents of ferrite phases in pearlite precipitating from austenite in multicomponent steel at temperature T and in Fe-C ystem at T' are the same the pearlite formation temperature diference, can be calculated from the FeX phase diagrams and the equilibrium temperature Al. Using Tp and Fe-C binary thermodynamic model, the driving forces for phase transformation from austenite to pearlite in multicomponent steels have been successfully calculated. Through the combination of simplified Zener and Hillert's model for pearlite growth with Johnson-Mehl equation, using data from known TTT diagrams, the interfacial energy parameter and activation energy for pearlite formation can be determined and expressed as functions of chemical composition in steels by regression analysis. The calculated starting curves of pearlitic transformation in some commercial steels agree well with the experimental data.
文摘Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from austenite in Fe-C binary system at temperature T'.is described as the temperature difference of proeutectiod ferrite formation, and can be calculated from the Fe-X diagrams and the equilibrium temperature A3. By introducing Tf and basing on the thermodynamic model for Fe-C binary alloy, the driving force for phase transformation from austenite to proeutectoid ferrite in multicomponent steels has been successfully calculated. Through the Johnson-Mehl equation and using the data hem known TTT diagrams, the relationship between the chemical composition and the intedecial edenly packeter as well as activation energy for proeutectoid ferrite formation can be calculated. The starting curves of proeutectoid ferritic transformation calculated in this way in some hypo-proeutectoid structural steels agree well with the erperimental data.
基金supported by the National Key Researchand Development Program of China(No.2017YFC0603102)the National Natural ScienceFoundation of China(No.U19B6003 and 41972125)。
文摘The uncertainty surrounding the thermal regimes of the ultra-deep strata in the Tarim and Sichuan basins,China,is unfavorable for further hydrocarbon exploration.This study summarizes and contrasts the present-day and paleo heat flow,geothermal gradient and deep formation temperatures of the Tarim and Sichuan basins.The average heat flow of the Tarim and Sichuan basins are 42.5±7.6 mW/m^(2)and 53.8±7.6 mW/m^(2),respectively,reflecting the characteristics of’cold’and’warm’basins.The geothermal gradient with unified depths of 0-5,000 m,0-6,000 m and 0-7,000 m in the Tarim Basin are 21.6±2.9℃/km,20.5±2.8℃/km and 19.6±2.8℃/km,respectively,while the geothermal gradient with unified depths of 0-5,000 m,0-6,000 m and 0-7,000 m in the Sichuan Basin are 21.9±2.3℃/km,22.1±2.5℃/km and23.3±2.4℃/km respectively.The differential change of the geothermal gradient between the Tarim and Sichuan basins with depth probably results from the rock thermal conductivity and heat production rate.The formation temperatures at depths of 6,000 m,7,000 m,8,000 m,9,000 m and 10,000 m in the Tarim Basin are 80℃-190℃,90℃-220℃,100℃-230℃,110℃-240℃and 120℃-250℃,respectively,while the formation temperatures at depths of 6,000 m,7,000 m,8,000 m and 9,000 m in the Sichuan Basin are 120℃-200℃,140℃-210℃,160℃-260℃and 180℃-280℃,respectively.The horizontal distribution pattern of the ultra-deep formation temperatures in the Tarim and Sichuan basins is mainly affected by the basement relief,fault activity and hydrothermal upwelling.The thermal modeling revealed that the paleo-heat flow in the interior of the Tarim Basin decreased since the early Cambrian with an early Permian abrupt peak,while that in the Sichuan Basin experienced three stages of steady state from Cambrian to early Permian,rapidly rising at the end of the early Permian and declining since the late Permian.The thermal regime of the Sichuan Basin was always higher than that of the Tarim Basin,which results in differential oil and gas generation and conservation in the ultra-deep ancient strata.This study not only promotes theoretical development in the exploration of ultra-deep geothermal fields,but also plays an important role in determining the maturation phase of the ultra-deep source rocks and the occurrence state of hydrocarbons in the Tarim and Sichuan basins.
文摘The crystal structure of ludwigite from Vranovac ore deposit （Boranja Mt., Serbia） was refined using the X-ray powder diffraction （XRPD） Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of： a=9.2515（2） A; b=12.3109（2） A; c=3.03712 （7） A; and V=345.91（1） A3. The calculated distances and angles are mostly in good agreement with the Mg2＋-Fe2＋ substitutions across the M（1） and M（3） sites, as well as with the Fe3＋-AI3＋ replacement in the M（4） site. However, the mean observed M（2）-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3＋ content in the M（2） site. Such replacement was compensated by slight increase of the Fe2＋ content in the M（4） site, resulting in the （Mg1.4sFe2＋o.46Fe3＋o.osMno.o2）2.o1 （Fe3＋o.94Fe2＋0.04Al0.02）1.00B1.00Os composition. The formation temperature was estimated to be about 500- 600C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M（3） and M（4） sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.
基金financial support by the Ministry of Science and Education of the Russian Federation(Grant No.FWZZ-2022-0014)RFBR within the framework of research project No.18-05-7007。
文摘Results of the investigation into the geothermal regime of the Fore-Yenisey sedimentary basin, formed during the collision and subsidence of the Kas-Turukhan microcontinent and the western margin of the Siberian craton in the late Neoproterozoic and early Paleozoic are reported. It was established that the structural and geothermal conditions of the upper Precambrian–Paleozoic sections are similar to those in the western regions of the Siberian platform and are characterized by rather low geothermal gradients(12.5–25.5 ℃/km). In the western parts of the basin, formation temperatures in the uppermost pre-Jurassic sediments are 50℃–85℃, decreasing eastward to 30℃–55℃. For the first time, the detailed geothermal model of the basin sedimentary fill was developed. This model allows predictions of the geothermal conditions of Earth’s interior.
文摘The gas hydrate formation in pipelines of industries and chemical plants can cause various operational damages and can increase economic risks.Hence,the knowledge of hydrate formation conditions has become a critical research study to overcome the problems arising from the formation of hydrates.In this study,we applied an algorithm to develop an LSSVM model to predict the formation temperature of natural gas hydrate for a comprehensive range of data points.Total 188 experimental data points were applied from the literature for the development of the LSSVM model.The input parameter was finalized based on the structure of hydrates by each gas species.The results obtained by the LSSVM model have good accuracy as compared with empirical correlations available in the literature.This model gave the squared correlation coefficient(R2),and root mean square error of 0.9901 and 0.59974,respectively.The composition of gases may affect the phase equilibrium condition of gas hydrates.The applied algorithm revealed that the developed LSSVM model could become a good alternative for calculating the formation temperature of hydrate for the range of all data sets.The results showed that the proposed LSSVM model could be applicable for the prediction of hydrate formation temperature for all data points.
