P2-type layered transition-metal oxides with high energy density and rich variety have attracted extensive attention for sodium-ion batteries(SIBs)in grid-scale energy storage application,but they usually suffer from ...P2-type layered transition-metal oxides with high energy density and rich variety have attracted extensive attention for sodium-ion batteries(SIBs)in grid-scale energy storage application,but they usually suffer from sluggish kinetics and large volume change upon cycling.Herein,we designed a highperformance P2-type Na_(0.67)Ni_(0.31)Mn_(0.67)Mo_(0.02)O_(2)(NNMMO)cathode with regulated electronic environment and Na^(+)zigzag ordering modulation via high-valence Mo6+stabilization engineering.The achieved NNMMO cathode exhibits a high-rate capability with a reversible capacity of 77.2 m Ah/g at 10 C and a long cycle life with a capacity retention of 75%at 2 C after 1000 cycles.In addition,in situ X-ray diffraction and ex-situ X-ray absorption fine structure spectroscopy characterizations verify that the presence of Mo^(6+)also stabilizes the desodiated structure through a pinning effect,achieving an extremely low volume change of 1.04%upon Na^(+)extraction.The quantified diffusional analysis and theoretical calculations demonstrate that the Mo^(6+)-doping improves the Na+diffusion kinetics,optimizes the energy band structure and enhances the TM-O bond strength.Additionally,the as-fabricated pouch cells by paring NNMMO cathode and hard carbon anode show impressive cycling stability with an energy density of 296.7 Wh/kg.This study broadens the perspective for high-valence metal ion doping to obtain superior cathode materials and pave the way for developing high-energy-density SIBs.展开更多
The Sn Se nanoparticles encapsulated in the carbon nanofibers(Sn Se@C)with microrod morphology and core-shell structure are prepared by electrospinning and annealing process,and investigated as anode materials for sod...The Sn Se nanoparticles encapsulated in the carbon nanofibers(Sn Se@C)with microrod morphology and core-shell structure are prepared by electrospinning and annealing process,and investigated as anode materials for sodium ion batteries.Benefiting from this unique structure,the Sn Se@C can deliver a reversible capacity of 283.8 m Ah g^(-1) after 500 cycles at a high current density of 1.0 A g^(-1).The sodium ion storage mechanisms of Sn Se are further characterized by ex-situ X-ray diffraction,high-resolution transmission electron microscope and selected area electron diffraction measurements.Besides,the excellent electrochemical performance of the electrodes is investigated by pseudocapacitance and in situ electrochemical impedance spectroscopy measurements.This work may provide a new avenue for synthesis of metal selenides with core-shell structure and a good idea for studying the kinetics process.展开更多
As a difficult problem, sidewall instability has been beset drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Due to com...As a difficult problem, sidewall instability has been beset drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Due to complex relationship between various factors which influence sidewall stability, it hasn’t been found a widely applied method to predicate sidewall stability so far. Therefore, in order to formulate corresponding measures to ensure successful drilling, searching for a kind of better method to forecast sidewall stability before drilling becomes an imperative and significant topic for drilling engineering. On the basis of traditional sidewall stability analytical method, we have put forward the Fuzzy Comprehensive Evaluation Method to forecast sidewall stability regulation using physico-chemical performance parameters of the clay mineral. This method has been improved by introducing the Analytic Hierarchy Process (AHP) and the Maximum Subjection Principle in the application process. After introducing Analytic Hierarchy Process to identify weight, and Maximum Subjection Principle to obtain evaluation results, it has reduced the influence of human factors and enhanced the accuracy of the fuzzy evaluation results. The application in Hailaer Area indicates that this method can predict sidewall stability of gas-oil well with high credibility and strong practicability.展开更多
Tin-based chalcogenides have attracted tremendous attention as an anode material for sodium storage owing to their unique structure and high theoretical capacity. Unfortunately, the large volume change and poor conduc...Tin-based chalcogenides have attracted tremendous attention as an anode material for sodium storage owing to their unique structure and high theoretical capacity. Unfortunately, the large volume change and poor conductivity lead to sluggish reaction kinetics and poor cycling performance. Herein, SnS_(0.5)Se_(0.5)nanoparticles coupled with N/S/Se triple-doped carbon nanofibers(SnS_(0.5)Se_(0.5)@NSSe-C) are designed and synthesized through electrospinning and annealing process. Benefiting from the synergistic effects of SnS_(0.5)Se_(0.5)and NSSe-C, the SnS_(0.5)Se_(0.5)@NSSe-C nanofibers exhibit a high reversible capacity and ultralong cycle life at higher current density for sodium-ion batteries. Furthermore, the sodium storage mechanism and electrochemical reaction kinetics of the SnS_(0.5)Se_(0.5)@NSSe-C composite are characterized by the in-situ measurements. The theoretical calculations further reveal the structural advantages of SnS_(0.5)Se_(0.5)@NSSeC composite, which exhibits a high adsorption energy of Na+. This work can provide a novel idea for the synthesis of ternary tin-based chalcogenides and is beneficial for the investigation of their reaction kinetics.展开更多
Commercial hydrocarbon reservoirs have been discovered in shallow-water areas of the Scotian Basin, Eastern Canada. However, knowledge about the structure and hydrocarbon accumulation characteristics of the basin is s...Commercial hydrocarbon reservoirs have been discovered in shallow-water areas of the Scotian Basin, Eastern Canada. However, knowledge about the structure and hydrocarbon accumulation characteristics of the basin is still insufficient, which constrains the oil and gas exploration in deep-water areas. Based on comprehensive data of magnetic anomalies, seismic survey, and drilling, this study determines the structure characteristics of the Scotian Basin and its hydrocarbon accumulation conditions in deep waters and evaluates the deep-water hydrocarbon exploration potential. The transform faults and basement structures in the northern basin control the sedimentary framework showing thick strata in east and thin strata in west of the basin. The bowl-shaped depression formed by thermal subsidence during the transitional phase and the confined environment (micro basins) caused by salt tectonics provide favorable conditions for the development of source rocks during the depression stage (also referred to as the depression period sequence) of the basin. The progradation of large shelf-margin deltas during the drift phase and steep continental slope provide favorable conditions for the deposition of slope-floor fans on continental margins of the basin. Moreover, the source-reservoir assemblage comprising the source rocks within the depression stage and the turbidite sandstones on the continental margin in the deep waters may form large deep-water turbidite sandstone reservoirs. This study will provide a valuable reference for the deep-water hydrocarbon exploration in the Scotian Basin.展开更多
基金partly supported by the National Natural Science Foundation of China(Nos.12275189 and 11705015)Natural Science Foundation of the Jiangsu Higher Education Institutions(No.23KJA430001)Collaborative Innovation Center of Suzhou Nano Science&Technology。
文摘P2-type layered transition-metal oxides with high energy density and rich variety have attracted extensive attention for sodium-ion batteries(SIBs)in grid-scale energy storage application,but they usually suffer from sluggish kinetics and large volume change upon cycling.Herein,we designed a highperformance P2-type Na_(0.67)Ni_(0.31)Mn_(0.67)Mo_(0.02)O_(2)(NNMMO)cathode with regulated electronic environment and Na^(+)zigzag ordering modulation via high-valence Mo6+stabilization engineering.The achieved NNMMO cathode exhibits a high-rate capability with a reversible capacity of 77.2 m Ah/g at 10 C and a long cycle life with a capacity retention of 75%at 2 C after 1000 cycles.In addition,in situ X-ray diffraction and ex-situ X-ray absorption fine structure spectroscopy characterizations verify that the presence of Mo^(6+)also stabilizes the desodiated structure through a pinning effect,achieving an extremely low volume change of 1.04%upon Na^(+)extraction.The quantified diffusional analysis and theoretical calculations demonstrate that the Mo^(6+)-doping improves the Na+diffusion kinetics,optimizes the energy band structure and enhances the TM-O bond strength.Additionally,the as-fabricated pouch cells by paring NNMMO cathode and hard carbon anode show impressive cycling stability with an energy density of 296.7 Wh/kg.This study broadens the perspective for high-valence metal ion doping to obtain superior cathode materials and pave the way for developing high-energy-density SIBs.
基金supported by the National Natural Science Foundation of China(Nos.U1832147,11705015)Natural Science Foundation of Jiangsu Educational Department(No.15KJA430001)+1 种基金Foundation of Jiangsu science and Technology Department(No.BA2016041)Science and Technology Development Plan Project in Suzhou(Nos.SYG201738,SYZ201710)。
文摘The Sn Se nanoparticles encapsulated in the carbon nanofibers(Sn Se@C)with microrod morphology and core-shell structure are prepared by electrospinning and annealing process,and investigated as anode materials for sodium ion batteries.Benefiting from this unique structure,the Sn Se@C can deliver a reversible capacity of 283.8 m Ah g^(-1) after 500 cycles at a high current density of 1.0 A g^(-1).The sodium ion storage mechanisms of Sn Se are further characterized by ex-situ X-ray diffraction,high-resolution transmission electron microscope and selected area electron diffraction measurements.Besides,the excellent electrochemical performance of the electrodes is investigated by pseudocapacitance and in situ electrochemical impedance spectroscopy measurements.This work may provide a new avenue for synthesis of metal selenides with core-shell structure and a good idea for studying the kinetics process.
文摘As a difficult problem, sidewall instability has been beset drilling workers all the time. Not only does it cause huge economic losses, but also it determines the success or failure of drilling engineering. Due to complex relationship between various factors which influence sidewall stability, it hasn’t been found a widely applied method to predicate sidewall stability so far. Therefore, in order to formulate corresponding measures to ensure successful drilling, searching for a kind of better method to forecast sidewall stability before drilling becomes an imperative and significant topic for drilling engineering. On the basis of traditional sidewall stability analytical method, we have put forward the Fuzzy Comprehensive Evaluation Method to forecast sidewall stability regulation using physico-chemical performance parameters of the clay mineral. This method has been improved by introducing the Analytic Hierarchy Process (AHP) and the Maximum Subjection Principle in the application process. After introducing Analytic Hierarchy Process to identify weight, and Maximum Subjection Principle to obtain evaluation results, it has reduced the influence of human factors and enhanced the accuracy of the fuzzy evaluation results. The application in Hailaer Area indicates that this method can predict sidewall stability of gas-oil well with high credibility and strong practicability.
基金supported by National Natural Science Foundation of China (No.U1832147)Jiangsu Provincial Double-Innovation Doctor Program (No.JSSCBS20210743)+1 种基金Anhui Key Laboratory of low temperature Co-fired Materials (No.2022LCA04)The Doctor of Suzhou University Scientific Research(No.2020BS014)。
文摘Tin-based chalcogenides have attracted tremendous attention as an anode material for sodium storage owing to their unique structure and high theoretical capacity. Unfortunately, the large volume change and poor conductivity lead to sluggish reaction kinetics and poor cycling performance. Herein, SnS_(0.5)Se_(0.5)nanoparticles coupled with N/S/Se triple-doped carbon nanofibers(SnS_(0.5)Se_(0.5)@NSSe-C) are designed and synthesized through electrospinning and annealing process. Benefiting from the synergistic effects of SnS_(0.5)Se_(0.5)and NSSe-C, the SnS_(0.5)Se_(0.5)@NSSe-C nanofibers exhibit a high reversible capacity and ultralong cycle life at higher current density for sodium-ion batteries. Furthermore, the sodium storage mechanism and electrochemical reaction kinetics of the SnS_(0.5)Se_(0.5)@NSSe-C composite are characterized by the in-situ measurements. The theoretical calculations further reveal the structural advantages of SnS_(0.5)Se_(0.5)@NSSeC composite, which exhibits a high adsorption energy of Na+. This work can provide a novel idea for the synthesis of ternary tin-based chalcogenides and is beneficial for the investigation of their reaction kinetics.
基金supported by the National Science and Technology Major Project of China(2016ZX05033)the Project of SINOPEC Science and Technology Department(P19021-2)the Basic Prospective Research Project of SINOPEC(P22214-2).
文摘Commercial hydrocarbon reservoirs have been discovered in shallow-water areas of the Scotian Basin, Eastern Canada. However, knowledge about the structure and hydrocarbon accumulation characteristics of the basin is still insufficient, which constrains the oil and gas exploration in deep-water areas. Based on comprehensive data of magnetic anomalies, seismic survey, and drilling, this study determines the structure characteristics of the Scotian Basin and its hydrocarbon accumulation conditions in deep waters and evaluates the deep-water hydrocarbon exploration potential. The transform faults and basement structures in the northern basin control the sedimentary framework showing thick strata in east and thin strata in west of the basin. The bowl-shaped depression formed by thermal subsidence during the transitional phase and the confined environment (micro basins) caused by salt tectonics provide favorable conditions for the development of source rocks during the depression stage (also referred to as the depression period sequence) of the basin. The progradation of large shelf-margin deltas during the drift phase and steep continental slope provide favorable conditions for the deposition of slope-floor fans on continental margins of the basin. Moreover, the source-reservoir assemblage comprising the source rocks within the depression stage and the turbidite sandstones on the continental margin in the deep waters may form large deep-water turbidite sandstone reservoirs. This study will provide a valuable reference for the deep-water hydrocarbon exploration in the Scotian Basin.
