The three-dimensional(3D)pore structures and permeability of shale are critical for forecasting gas production capacity and guiding pressure differential control in practical reservoir extraction.However,few investiga...The three-dimensional(3D)pore structures and permeability of shale are critical for forecasting gas production capacity and guiding pressure differential control in practical reservoir extraction.However,few investigations have analyzed the effects of microscopic organic matter(OM)morphology and 3D pore nanostructures on the stress sensitivity,which are precisely the most unique and controlling factors of reservoir quality in shales.In this study,ultra-high nanoscale-resolution imaging experiments,i.e.focused ion beam-scanning electron microscopy(FIB-SEMs),were conducted on two organic-rich shale samples from Longmaxi and Wufeng Formations in northern Guizhou Depression,China.Pore morphology,porosity of 3D pore nanostructures,pore size distribution,and connectivity of the six selected regions of interest(including clump-shaped OMs,interstitial OMs,framboidal pyrite,and microfractures)were qualitatively and quantitatively characterized.Pulse decay permeability(PDP)measurement was used to investigate the variation patterns of stress-dependent permeability and stress sensitivity of shales under different confining pressures and pore pressures,and the results were then used to calculate the Biot coefficients for the two shale formations.The results showed that the samples have high OM porosity and 85%of the OM pores have the radius of less than 40 nm.The OM morphology and pore structure characteristics of the Longmaxi and Wufeng Formations were distinctly different.In particular,the OM in the Wufeng Formation samples developed some OM pores with radius larger than500 nm,which significantly improved the connectivity.The macroscopic permeability strongly depends on the permeability of OM pores.The stress sensitivity of permeability of Wufeng Formation was significantly lower than that of Longmaxi Formation,due to the differences in OM morphology and pore structures.The Biot coefficients of 0.729 and 0.697 were obtained for the Longmaxi and Wufeng Formations,respectively.展开更多
Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) ...Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.展开更多
The membrane permeability coefficient for sodium and potassium ions in unicellular organisms can be calculated using the data for cell volume, surface and mean generation time during growth and dividing of cells by bi...The membrane permeability coefficient for sodium and potassium ions in unicellular organisms can be calculated using the data for cell volume, surface and mean generation time during growth and dividing of cells by binary. Accordingly theory of proposed method, the membrane permeability coefficients for passed trough outer cell membrane sodium and potassium ions, is equal to the volume of unicellular organism divided to product between cell surface and mean generation time of cells. The calculated by this way diapason of values overlaps with experimentally measured diapason of values of permeability coefficient for sodium and potassium ions. The deviation between the theoretically calculated and experimentally measured values of permeability coefficient does not exceed one order of magnitude.展开更多
The sealing performance of a bentonite barrier is highly dependent on its seepage characteristics, which are directly related to the characteristics of its pore structure. Based on scanning electron microscopy(SEM) an...The sealing performance of a bentonite barrier is highly dependent on its seepage characteristics, which are directly related to the characteristics of its pore structure. Based on scanning electron microscopy(SEM) and focused ion beam-SEM(FIB-SEM), the pore structure of bentonite was characterized at different scales. First, a reasonable gray threshold was determined through back analysis, and the image was binarized based on the threshold. In addition, binary images were used to analyze bentonite’s pore structure(porosity and pore size distribution). Furthermore, the effects of different algorithms on the pore structure characterization were evaluated. Then, permeability calculations were performed based on the previous pore structure characteristics and a modified permeability prediction model. For permeability prediction based on the three-dimensional model, the effect of pore tortuosity was also considered. Finally, the accuracy of numerical calculations was verified by conducting macroscopic gas and alcohol permeability experiments. This approach provides a better understanding of the microscale mechanism of gas transport in bentonite and the importance of pore structures at different scales in determining its seepage characteristics.展开更多
The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed...The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]Fe+C saturation|ZrO2(MgO)|(FeO)(slag)|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.展开更多
The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed...The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]_(Fe+C saturation)[ZrO_2(MgO)|(FeO)_(slag))|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.展开更多
To characterize differences in soybean resistance to salt stress, two soybean species, the wild salt-tolerant soybean Glycine cyrtoloba(serial number ACC547) and the cultivated salt-sensitive soybean G. max(cv. Melros...To characterize differences in soybean resistance to salt stress, two soybean species, the wild salt-tolerant soybean Glycine cyrtoloba(serial number ACC547) and the cultivated salt-sensitive soybean G. max(cv. Melrose) were treated with 0, 50, 100, or 150 mmol L-1Na Cl for 5 days. A series of physiological parameters were determined in both shoots and roots, including content of chlorophyll(Chl) and malondialdehyde(MDA); electrolyte leakage(EL); hydrogen peroxide(H2O2) concentration; superoxide oxygen radical(O2-)production rate; activities of several enzymes including superoxide dismutase(SOD),catalase(CAT), and peroxidase(POD); and selective ion(Na+and K+) accumulation. Our results showed that the relative salt tolerance of ACC547 was associated with lower loss of Chl content; lower MDA content, EL, H2O2 concentration, and O2-production rate in both shoots and roots; higher POD activity caused by new isoforms in roots; and higher K+concentration and K+/Na+ratio in shoots. These results suggested that relative lower membrane injury, efficient K+vs. Na+selective accumulation, and newly induced POD isoenzymes are mechanisms of salt tolerance in soybean.展开更多
Through the rapid chloride ion penetration test,the influence of fly ash and slag on chloride ion permeability and microstructure of concrete was studied.The results indicate that the addition of fly ash increases con...Through the rapid chloride ion penetration test,the influence of fly ash and slag on chloride ion permeability and microstructure of concrete was studied.The results indicate that the addition of fly ash increases concrete permeability at 28 days.With the slag content of 20% and 30%,the permeability of concrete at 28 days is reduced.The positive effect of slag is due to its relatively stronger pozzolanic reactive ability resulted in the most probable pore size and total porosity decreased.When the slag content reaches 40%,the concrete permeability showes the tendency ofincrease.展开更多
The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.0...The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.03,0.06,0.09,0.12and 0.15)were employed to modify the permeability(μ)and permittivity(ε)of the Mg Cd ferrites.X-ray diffraction,scanning electron microscopy(SEM),vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples.The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method.The surface morphology SEM confirms that with increasing Sm^(3+)concentration,the grain shape changes from a polygon to a circle.Moreover,the dielectric permittivity can reach a value of 23.The excellent properties obtained in Sm^(3+)-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.展开更多
基金supported by the National Key R&D Program of China(Grant No.2020YFA0711802)the Strategic Program of Chinese Academy of Sciences(Grant No.XDB10030400)。
文摘The three-dimensional(3D)pore structures and permeability of shale are critical for forecasting gas production capacity and guiding pressure differential control in practical reservoir extraction.However,few investigations have analyzed the effects of microscopic organic matter(OM)morphology and 3D pore nanostructures on the stress sensitivity,which are precisely the most unique and controlling factors of reservoir quality in shales.In this study,ultra-high nanoscale-resolution imaging experiments,i.e.focused ion beam-scanning electron microscopy(FIB-SEMs),were conducted on two organic-rich shale samples from Longmaxi and Wufeng Formations in northern Guizhou Depression,China.Pore morphology,porosity of 3D pore nanostructures,pore size distribution,and connectivity of the six selected regions of interest(including clump-shaped OMs,interstitial OMs,framboidal pyrite,and microfractures)were qualitatively and quantitatively characterized.Pulse decay permeability(PDP)measurement was used to investigate the variation patterns of stress-dependent permeability and stress sensitivity of shales under different confining pressures and pore pressures,and the results were then used to calculate the Biot coefficients for the two shale formations.The results showed that the samples have high OM porosity and 85%of the OM pores have the radius of less than 40 nm.The OM morphology and pore structure characteristics of the Longmaxi and Wufeng Formations were distinctly different.In particular,the OM in the Wufeng Formation samples developed some OM pores with radius larger than500 nm,which significantly improved the connectivity.The macroscopic permeability strongly depends on the permeability of OM pores.The stress sensitivity of permeability of Wufeng Formation was significantly lower than that of Longmaxi Formation,due to the differences in OM morphology and pore structures.The Biot coefficients of 0.729 and 0.697 were obtained for the Longmaxi and Wufeng Formations,respectively.
基金National Natural Science Foundations of China(Nos.21477018,21007010)the Fundamental Research Funds for the Central Universities,China(No.15D111323)+1 种基金Hunan Province Ministry of Transportation Scientific Research Projects,China(Nos.200908,201105)Ministry of Transport Science and Technology Program,China(No.2010353343290)
文摘Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.
文摘The membrane permeability coefficient for sodium and potassium ions in unicellular organisms can be calculated using the data for cell volume, surface and mean generation time during growth and dividing of cells by binary. Accordingly theory of proposed method, the membrane permeability coefficients for passed trough outer cell membrane sodium and potassium ions, is equal to the volume of unicellular organism divided to product between cell surface and mean generation time of cells. The calculated by this way diapason of values overlaps with experimentally measured diapason of values of permeability coefficient for sodium and potassium ions. The deviation between the theoretically calculated and experimentally measured values of permeability coefficient does not exceed one order of magnitude.
基金financially supported by grants from the National Natural Science Foundation of China (No. 51422301)Beijing Higher Education Young Elite Teacher Project (No. 29201493)the Fundamental Research Funds for the Central Universities(No.YWF-16-BJ-Y-68)
基金support of the National Natural Science Foundation of China (Grant Nos. 52174133 and 51809263)China Atomic Energy Authority。
文摘The sealing performance of a bentonite barrier is highly dependent on its seepage characteristics, which are directly related to the characteristics of its pore structure. Based on scanning electron microscopy(SEM) and focused ion beam-SEM(FIB-SEM), the pore structure of bentonite was characterized at different scales. First, a reasonable gray threshold was determined through back analysis, and the image was binarized based on the threshold. In addition, binary images were used to analyze bentonite’s pore structure(porosity and pore size distribution). Furthermore, the effects of different algorithms on the pore structure characterization were evaluated. Then, permeability calculations were performed based on the previous pore structure characteristics and a modified permeability prediction model. For permeability prediction based on the three-dimensional model, the effect of pore tortuosity was also considered. Finally, the accuracy of numerical calculations was verified by conducting macroscopic gas and alcohol permeability experiments. This approach provides a better understanding of the microscale mechanism of gas transport in bentonite and the importance of pore structures at different scales in determining its seepage characteristics.
基金This work was financially supported by the National Natural Science Foundation of China (No.59934090) and the National Key Basic Research and Development Program of China (No.G1998061506)
文摘The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]Fe+C saturation|ZrO2(MgO)|(FeO)(slag)|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.
文摘The oxygen-ion-permeable membrane galvanic short-circuit method has been developed, in which pure metal was directly extracted from the molten oxide slag, and no external voltage is applied. The galvanic cell employed in the experiment was as follows: graphite rod|[O]_(Fe+C saturation)[ZrO_2(MgO)|(FeO)_(slag))|Fe rod. The reduction current in the galvanic cell consisted of an external short-circuit current and an interior short-circuit current in the oxygen-ion-permeable membrane. The real-time variation of external circuit reduction ratio of the molten slag could be obtained from the curve of the external circuit current to the time.
基金supported by the National Natural Science Foundation of China(31171462)the Natural Science Foundation of Ningbo(2014A610198)
文摘To characterize differences in soybean resistance to salt stress, two soybean species, the wild salt-tolerant soybean Glycine cyrtoloba(serial number ACC547) and the cultivated salt-sensitive soybean G. max(cv. Melrose) were treated with 0, 50, 100, or 150 mmol L-1Na Cl for 5 days. A series of physiological parameters were determined in both shoots and roots, including content of chlorophyll(Chl) and malondialdehyde(MDA); electrolyte leakage(EL); hydrogen peroxide(H2O2) concentration; superoxide oxygen radical(O2-)production rate; activities of several enzymes including superoxide dismutase(SOD),catalase(CAT), and peroxidase(POD); and selective ion(Na+and K+) accumulation. Our results showed that the relative salt tolerance of ACC547 was associated with lower loss of Chl content; lower MDA content, EL, H2O2 concentration, and O2-production rate in both shoots and roots; higher POD activity caused by new isoforms in roots; and higher K+concentration and K+/Na+ratio in shoots. These results suggested that relative lower membrane injury, efficient K+vs. Na+selective accumulation, and newly induced POD isoenzymes are mechanisms of salt tolerance in soybean.
基金Funded by the National Natural Science Foundation of China (No.50070819)
文摘Through the rapid chloride ion penetration test,the influence of fly ash and slag on chloride ion permeability and microstructure of concrete was studied.The results indicate that the addition of fly ash increases concrete permeability at 28 days.With the slag content of 20% and 30%,the permeability of concrete at 28 days is reduced.The positive effect of slag is due to its relatively stronger pozzolanic reactive ability resulted in the most probable pore size and total porosity decreased.When the slag content reaches 40%,the concrete permeability showes the tendency ofincrease.
基金the National Key Research and Development Program of China(Grant No.2018YFE0115500)the National Natural Science Foundation of China(Grant Nos.51902037 and 62005033)+2 种基金the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices(Grant No.KFJJ201912)the Science and Technology Project Affiliated to the Education Department of Chongqing Municipality(Grant No.KJQN201900615)the Nature Science Foundation of Chongqing(Grant No.cstc2019jcyjmsxm X0696)。
文摘The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.03,0.06,0.09,0.12and 0.15)were employed to modify the permeability(μ)and permittivity(ε)of the Mg Cd ferrites.X-ray diffraction,scanning electron microscopy(SEM),vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples.The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method.The surface morphology SEM confirms that with increasing Sm^(3+)concentration,the grain shape changes from a polygon to a circle.Moreover,the dielectric permittivity can reach a value of 23.The excellent properties obtained in Sm^(3+)-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.
