Based on the unique catalytic properties of precious metals,the introduction of precious metals into metal oxide semiconductors will greatly improve the gas-sensitive properties of materials.As a new type of porous ma...Based on the unique catalytic properties of precious metals,the introduction of precious metals into metal oxide semiconductors will greatly improve the gas-sensitive properties of materials.As a new type of porous material,metal–organic frameworks(MOF)can be used for gas separation and adsorption due to their adjustable pore size and acceptable thermal stability.In this work,the ZIF-71 MOF was synthesized on CuO nanofibers doped with different concentrations of Ru to form a Ru–CuO@ZIF-71 nanocomposite sensor,which was then used for H_(2)S detection.The sensor shows sensitivity to trace amounts of H_(2)S gas(100 ppb),and the response is greatly enhanced at the optimal Ru doping ratio and operating temperature.The introduction of the ZIF-71 membrane can significantly increase the selectivity of the sensor while further improving the sensitivity.Finally,the possible sensing mechanism of the Ru–CuO@ZIF-71 sensor was explored.The enhancement of the H_(2)S gas sensing properties may be attributed to the catalysis of Ru and the formation of the Schottky junction at the Ru–CuO interface.Besides,the calculation based on density functional theory reveals enhanced adsorption capacities of CuO for H_(2)S after Ru doping.Therefore,the Ru–CuO@ZIF-71 sensor has strong application potential in exhaled gas detection and portable detection of H_(2)S gas in industrial environments.展开更多
The shortage of CO_(2) source and the challenges associated with the separation of pure CO_(2) have led to a growing interest in the potential utilization of CO_(2)-contained IWG.Therefore,this study has established a...The shortage of CO_(2) source and the challenges associated with the separation of pure CO_(2) have led to a growing interest in the potential utilization of CO_(2)-contained IWG.Therefore,this study has established an acid-rock interaction kinetic model to characterize the long-term interactions between CO_(2)-contained IWG and shale.The findings delineate the reaction process into three phases:during the initial 10 years,solubility trapping predominates,with minimal mineral dissolution.This increases shale porosity,promoting the diffusion and storage range of CO_(2)-contained IWG.Between 10 and 300 years,mineral dissolution/precipitation assumes primacy,with mineral trapping gradually supplanting dissolution.Notably,shale porosity diminishes by a minimum of approximately 40%,effectively inhibiting gas leakage.After 300 years,equilibrium is reached,with rock porosity consistently lower than the initial porosity.Throughout the entire reaction process,as the initial CO_(2) concentration decreases,the initial pH drops from 4.42 to 3.61,resulting in a roughly 20%increase in porosity.Additionally,it is necessary to regulate its concentration to avoid H_(2)S leakage during CO_(2)-contained IWG geological sequestration.And particular attention should be directed towards the risk of gas leakage when the IWG exhibit high levels of SO_(2) or NO_(2).展开更多
A novel SnO2-based gas anode was developed for aluminum electrolysis in molten cryolite at 850 ＆#176;C to reduce energy consumption and decrease CO2 emissions. Hydrogen was introduced into the anode, participating in...A novel SnO2-based gas anode was developed for aluminum electrolysis in molten cryolite at 850 ＆#176;C to reduce energy consumption and decrease CO2 emissions. Hydrogen was introduced into the anode, participating in the anode reaction. Carbon and aluminum were used as the cathode and reference electrodes, respectively. Cyclic voltammetry was applied in the cell to investigate the electrochemical behavior of oxygen ion on platinum and SnO2-based materials. The potential for oxygen evolution on these electrode materials was determined. Then, galvanostatic electrolysis was performed on the gas anode, showing a significant depolarization effect （a decrease of ~0.8 V of the anode potential） after the introduction of hydrogen, compared with no gas introduction or the introduction of argon. The results indicate the involvement of hydrogen in the anode reaction （three-phase-boundary reaction including gas, electrolyte and electrode） and give the possibility for the utilization of reducing gas anodes for aluminum electrolysis.展开更多
Nitrogen dioxide(NO2),a hazardous gas with acidic nature,is continuously being liberated in the atmosphere due to human activity.The NO2 sensors based on traditional materials have limitations of high-temperature requ...Nitrogen dioxide(NO2),a hazardous gas with acidic nature,is continuously being liberated in the atmosphere due to human activity.The NO2 sensors based on traditional materials have limitations of high-temperature requirements,slow recovery,and performance degradation under harsh environmental conditions.These limitations of traditional materials are forcing the scientific community to discover future alternative NO2 sensitive materials.Molybdenum disulfide(MoS2)has emerged as a potential candidate for developing next-generation NO2 gas sensors.MoS2 has a large surface area for NO2 molecules adsorption with controllable morphologies,facile integration with other materials and compatibility with internet of things(IoT)devices.The aim of this review is to provide a detailed overview of the fabrication of MoS2 chemiresistance sensors in terms of devices(resistor and transistor),layer thickness,morphology control,defect tailoring,heterostructure,metal nanoparticle doping,and through light illumination.Moreover,the experimental and theoretical aspects used in designing MoS2-based NO2 sensors are also discussed extensively.Finally,the review concludes the challenges and future perspectives to further enhance the gas-sensing performance of MoS2.Understanding and addressing these issues are expected to yield the development of highly reliable and industry standard chemiresistance NO2 gas sensors for environmental monitoring.展开更多
High-purity N2 was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and puri- fication, and to meet the effi...High-purity N2 was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and puri- fication, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry （MC-ICPMS） analysis. For Cu isotope separation, our results indicated that at a gas flow rate 〉60 mL/min, the separation chromatographic peaks broadened and the re-covery rate decreased to 〈99.2%. On the other hand, no significant change in the Cu peaks was ob- served at a gas flow rate of 20 mL/min and the recovery rate was determined to be 〉99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a±2 SD error range. The separation time was reduced from the traditional 10 h （without N2） to 4 h （with N2）, indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 （US Geological Survey andesite standard sample） accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N2, the purified liquid comprised Rb/Sr and Sm/Nd ratios of 〈0.000 049 and 〈0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a±2 SD error range and the total separation time was shortened from 2 d to 〈10 h.展开更多
The stable and crystalline phase of pure nano- structured CeO2 was directly synthesized by flame-assisted spray pyrolysis and solid state diffusion route. Different characterization techniques, including X-ray diffrac...The stable and crystalline phase of pure nano- structured CeO2 was directly synthesized by flame-assisted spray pyrolysis and solid state diffusion route. Different characterization techniques, including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Fourier trans- form infrared spectroscopy （FTIR）, ultraviolet-visible （UV- Vis）, and thermo gravimetric analysis （TGA） were employed to examine the structural, morphological, optical, and thermal properties of the final product. Similarly, the comparative carbon dioxide （CO2）-sensing response of as-synthesized CeO2 nanoparticles by both routes was also reported. The CeO2 nanoparticles synthesized by solid state diffusion method exhibit good sensitivity （3.38 %） at room temperature, low operating temperature （398 K）, fast response time （32 s）, and recovery time （36 s） along with good stability.展开更多
In order to increase drilling speed in deep complicated formations in Kela-2 gas field, Tarim Basin, Xinjiang, west China, it is important to predict the formation lithology for drilling bit optimization. Based on the...In order to increase drilling speed in deep complicated formations in Kela-2 gas field, Tarim Basin, Xinjiang, west China, it is important to predict the formation lithology for drilling bit optimization. Based on the conventional back propagation （BP） model, an improved BP model was proposed, with main modifications of back propagation of error, self-adapting algorithm, and activation function, also a prediction program was developed. The improved BP model was successfully applied to predicting the lithology of formations to be drilled in the Kela-2 gas field.展开更多
The sensitivity and selectivity to H_2 of a new In_2O_3-based gas sensor were improvedsignificantly by surface chemical modification. A dense layer of SiO_2 near the surface of the porousIn_2O_3 bead was formed by che...The sensitivity and selectivity to H_2 of a new In_2O_3-based gas sensor were improvedsignificantly by surface chemical modification. A dense layer of SiO_2 near the surface of the porousIn_2O_3 bead was formed by chemical vapor deposition(CVD)of diethoxydimethysilane(DEMS).The dense layer functioned as a molecular sieve, thereby the diffusion of gases with large moleculardiameters,except for H_2, was effectively controlled, resulting in a prominent selectivity and highsensitivity for H_2. The working mechanism of the sensor was also presented.展开更多
CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas m...CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment.展开更多
Agriculture is the foundation of social development.Under the pressure of population growth,natural disasters,environmental pollution,climate change,and food safety,the interdisciplinary"new agriculture"is b...Agriculture is the foundation of social development.Under the pressure of population growth,natural disasters,environmental pollution,climate change,and food safety,the interdisciplinary"new agriculture"is becoming an important trend of modern agriculture.In fact,new agriculture is not only the foundation of great health and new energy sources,but is also the cornerstone of national food security,energy security,and biosafety.Hydrogen agronomy focuses mainly on the mechanism of hydrogen gas(H2)biology effects in agriculture,and provides a theoretical foundation for the practice of hydrogen agriculture,a component of the new agriculture.Previous research on the biological effects of H2 focused chiefly on medicine.The mechanism of selective antioxidant is the main theoretical basis of hydrogen medicine.Subsequent experiments have demonstrated that H2 can regulate the growth and development of plant crops,edible fungus,and livestock,and enhance the tolerance of these agriculturally important organisms against abiotic and biotic stresses.Even more importantly,H2 can regulate the growth and development of crops by changing the soil microbial community composition and structure.Use of H2 can also improve the nutritional value and postharvest quality of agricultural products.Researchers have also shown that the biological functions of molecular hydrogen are mediated by modulating reactive oxygen species(ROS),nitric oxide(NO),and carbon monoxide(CO)signaling cascades in plants and microbes.This review summarizes and clarifies the history of hydrogen agronomy and describes recent progress in the field.We also argue that emerging hydrogen agriculture will be an important direction in the new agriculture.Further,we discuss several scientific problems in hydrogen agronomy,and suggest that the future of hydrogen agronomy depends on contributions by multiple disciplines.Important future research directions of hydrogen agronomy include hydrogen agriculture in special environments,such as islands,reefs,aircraft,and outer space.展开更多
A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper slag.The effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,...A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper slag.The effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,roasting temperature,roasting time,particle size of modified slag and magnetic flux density on the oxidized modification and magnetic separation were investigated by comparison of the X-ray diffraction patterns and iron recovery ratio.The optimum conditions for recovering iron by oxidizing roasting and magnetic separation are as follows:calcium oxide content of 25 wt.%,mixed gas flow rates of CO2 and CO of 180 and 20 mL/min,oxidizing roasting at 1323 K for 2 h,grinding the modified slag to 38.5-25.0μm and magnetic separation at 170 mT.The mineralogical and microstructural characteristics of modified slag revealed that the iron-bearing minerals in the copper slag were oxidized,the generated magnetite grew into large particles,and the silicate in copper slag was combined with calcium oxide to form calcium silicate.Finally,the iron-bearing concentrate with an iron grade of 54.79%and iron recovery ratio of 80.14%was effectively obtained.展开更多
CO2 flooding is regarded as an important method for enhanced oil recovery （EOR） and greenhouse gas control. However, the heterogeneity prevalently dis- tributed in reservoirs inhibits the performance of this technol...CO2 flooding is regarded as an important method for enhanced oil recovery （EOR） and greenhouse gas control. However, the heterogeneity prevalently dis- tributed in reservoirs inhibits the performance of this technology. The sweep efficiency can be significantly reduced especially in the presence of ＂thief zones＂. Hence, gas channeling blocking and mobility control are important technical issues for the success of CO2 injection. Normally, crosslinked gels have the potential to block gas channels, but the gelation time control poses challenges to this method. In this study, a new method for selectively blocking CO2 channeling is proposed, which is based on a type of CO2-sensitive gel system （modified polyacry- lamide-methenamine-resorcinol gel system） to form gel in situ. A CO2-sensitive gel system is when gelation or solidification will be triggered by CO2 in the reservoir to block gas channels. The CO2-sensitivity of the gel system was demonstrated in parallel bottle tests of gel in N2 and CO2 atmospheres. Sand pack flow experiments were con- ducted to investigate the shutoff capacity of the gel system under different conditions. The injectivity of the gel system was studied via viscosity measurements. The results indi- cate that this gel system was sensitive to CO2 and had good performance of channeling blocking in porous media. Advantageous viscosity-temperature characteristics were achieved in this work. The effectiveness for EOR in heterogeneous formations based on this gel system was demonstrated using displacement tests conducted in double sand packs. The experimental results can provide guideli- nes for the deployment of theCO2-sensitive gel system for field applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52003297 and 22302233)the Open Project of State Key Laboratory of Chemical Safety(No.SKLCS-2024020)+2 种基金the National Key R&D Program of China(Nos.2022YFB3205501 and 2022YFB3205504)and the Fundamental Research Funds for the Central Universities(No.24CX02014A)the Fund of State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China).
文摘Based on the unique catalytic properties of precious metals,the introduction of precious metals into metal oxide semiconductors will greatly improve the gas-sensitive properties of materials.As a new type of porous material,metal–organic frameworks(MOF)can be used for gas separation and adsorption due to their adjustable pore size and acceptable thermal stability.In this work,the ZIF-71 MOF was synthesized on CuO nanofibers doped with different concentrations of Ru to form a Ru–CuO@ZIF-71 nanocomposite sensor,which was then used for H_(2)S detection.The sensor shows sensitivity to trace amounts of H_(2)S gas(100 ppb),and the response is greatly enhanced at the optimal Ru doping ratio and operating temperature.The introduction of the ZIF-71 membrane can significantly increase the selectivity of the sensor while further improving the sensitivity.Finally,the possible sensing mechanism of the Ru–CuO@ZIF-71 sensor was explored.The enhancement of the H_(2)S gas sensing properties may be attributed to the catalysis of Ru and the formation of the Schottky junction at the Ru–CuO interface.Besides,the calculation based on density functional theory reveals enhanced adsorption capacities of CuO for H_(2)S after Ru doping.Therefore,the Ru–CuO@ZIF-71 sensor has strong application potential in exhaled gas detection and portable detection of H_(2)S gas in industrial environments.
基金supported by the National Natural ScienceFoundation of China(No.52074316)PetroChina CompanyLimited(grant number 2019E-2608)。
文摘The shortage of CO_(2) source and the challenges associated with the separation of pure CO_(2) have led to a growing interest in the potential utilization of CO_(2)-contained IWG.Therefore,this study has established an acid-rock interaction kinetic model to characterize the long-term interactions between CO_(2)-contained IWG and shale.The findings delineate the reaction process into three phases:during the initial 10 years,solubility trapping predominates,with minimal mineral dissolution.This increases shale porosity,promoting the diffusion and storage range of CO_(2)-contained IWG.Between 10 and 300 years,mineral dissolution/precipitation assumes primacy,with mineral trapping gradually supplanting dissolution.Notably,shale porosity diminishes by a minimum of approximately 40%,effectively inhibiting gas leakage.After 300 years,equilibrium is reached,with rock porosity consistently lower than the initial porosity.Throughout the entire reaction process,as the initial CO_(2) concentration decreases,the initial pH drops from 4.42 to 3.61,resulting in a roughly 20%increase in porosity.Additionally,it is necessary to regulate its concentration to avoid H_(2)S leakage during CO_(2)-contained IWG geological sequestration.And particular attention should be directed towards the risk of gas leakage when the IWG exhibit high levels of SO_(2) or NO_(2).
基金Project(51404001)supported by the National Natural Science Foundation of ChinaProject([2014]1685)supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education,China
文摘A novel SnO2-based gas anode was developed for aluminum electrolysis in molten cryolite at 850 ＆#176;C to reduce energy consumption and decrease CO2 emissions. Hydrogen was introduced into the anode, participating in the anode reaction. Carbon and aluminum were used as the cathode and reference electrodes, respectively. Cyclic voltammetry was applied in the cell to investigate the electrochemical behavior of oxygen ion on platinum and SnO2-based materials. The potential for oxygen evolution on these electrode materials was determined. Then, galvanostatic electrolysis was performed on the gas anode, showing a significant depolarization effect （a decrease of ~0.8 V of the anode potential） after the introduction of hydrogen, compared with no gas introduction or the introduction of argon. The results indicate the involvement of hydrogen in the anode reaction （three-phase-boundary reaction including gas, electrolyte and electrode） and give the possibility for the utilization of reducing gas anodes for aluminum electrolysis.
基金the Department of Atomic Energy(DAE)under Project No.34/20/09/2015/BRNSthe Department of Physics,IIT Ropar for providing financial support and the research facility。
文摘Nitrogen dioxide(NO2),a hazardous gas with acidic nature,is continuously being liberated in the atmosphere due to human activity.The NO2 sensors based on traditional materials have limitations of high-temperature requirements,slow recovery,and performance degradation under harsh environmental conditions.These limitations of traditional materials are forcing the scientific community to discover future alternative NO2 sensitive materials.Molybdenum disulfide(MoS2)has emerged as a potential candidate for developing next-generation NO2 gas sensors.MoS2 has a large surface area for NO2 molecules adsorption with controllable morphologies,facile integration with other materials and compatibility with internet of things(IoT)devices.The aim of this review is to provide a detailed overview of the fabrication of MoS2 chemiresistance sensors in terms of devices(resistor and transistor),layer thickness,morphology control,defect tailoring,heterostructure,metal nanoparticle doping,and through light illumination.Moreover,the experimental and theoretical aspects used in designing MoS2-based NO2 sensors are also discussed extensively.Finally,the review concludes the challenges and future perspectives to further enhance the gas-sensing performance of MoS2.Understanding and addressing these issues are expected to yield the development of highly reliable and industry standard chemiresistance NO2 gas sensors for environmental monitoring.
基金co-supported by the National Natural Science Foundation of China (Nos. 41427804, 41421002, 41373004)Program for Changjiang Scholars and Innovative Research Team in University of China (No. IRT1281)the MOST Research Foundation from the State Key Laboratory of Continental Dynamics
文摘High-purity N2 was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and puri- fication, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry （MC-ICPMS） analysis. For Cu isotope separation, our results indicated that at a gas flow rate 〉60 mL/min, the separation chromatographic peaks broadened and the re-covery rate decreased to 〈99.2%. On the other hand, no significant change in the Cu peaks was ob- served at a gas flow rate of 20 mL/min and the recovery rate was determined to be 〉99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a±2 SD error range. The separation time was reduced from the traditional 10 h （without N2） to 4 h （with N2）, indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 （US Geological Survey andesite standard sample） accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N2, the purified liquid comprised Rb/Sr and Sm/Nd ratios of 〈0.000 049 and 〈0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a±2 SD error range and the total separation time was shortened from 2 d to 〈10 h.
文摘The stable and crystalline phase of pure nano- structured CeO2 was directly synthesized by flame-assisted spray pyrolysis and solid state diffusion route. Different characterization techniques, including X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Fourier trans- form infrared spectroscopy （FTIR）, ultraviolet-visible （UV- Vis）, and thermo gravimetric analysis （TGA） were employed to examine the structural, morphological, optical, and thermal properties of the final product. Similarly, the comparative carbon dioxide （CO2）-sensing response of as-synthesized CeO2 nanoparticles by both routes was also reported. The CeO2 nanoparticles synthesized by solid state diffusion method exhibit good sensitivity （3.38 %） at room temperature, low operating temperature （398 K）, fast response time （32 s）, and recovery time （36 s） along with good stability.
文摘In order to increase drilling speed in deep complicated formations in Kela-2 gas field, Tarim Basin, Xinjiang, west China, it is important to predict the formation lithology for drilling bit optimization. Based on the conventional back propagation （BP） model, an improved BP model was proposed, with main modifications of back propagation of error, self-adapting algorithm, and activation function, also a prediction program was developed. The improved BP model was successfully applied to predicting the lithology of formations to be drilled in the Kela-2 gas field.
文摘The sensitivity and selectivity to H_2 of a new In_2O_3-based gas sensor were improvedsignificantly by surface chemical modification. A dense layer of SiO_2 near the surface of the porousIn_2O_3 bead was formed by chemical vapor deposition(CVD)of diethoxydimethysilane(DEMS).The dense layer functioned as a molecular sieve, thereby the diffusion of gases with large moleculardiameters,except for H_2, was effectively controlled, resulting in a prominent selectivity and highsensitivity for H_2. The working mechanism of the sensor was also presented.
基金supported by National Natural Science Foundation of China(No.51337006)。
文摘CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment.
基金the National Natural Science Foundation of China(No.31972396)the Foshan Agriculture Science and Technology Project(Foshan City Budget,No.140,2019)the Funding from Center of Hydrogen Science,Shanghai Jiao Tong University,China。
文摘Agriculture is the foundation of social development.Under the pressure of population growth,natural disasters,environmental pollution,climate change,and food safety,the interdisciplinary"new agriculture"is becoming an important trend of modern agriculture.In fact,new agriculture is not only the foundation of great health and new energy sources,but is also the cornerstone of national food security,energy security,and biosafety.Hydrogen agronomy focuses mainly on the mechanism of hydrogen gas(H2)biology effects in agriculture,and provides a theoretical foundation for the practice of hydrogen agriculture,a component of the new agriculture.Previous research on the biological effects of H2 focused chiefly on medicine.The mechanism of selective antioxidant is the main theoretical basis of hydrogen medicine.Subsequent experiments have demonstrated that H2 can regulate the growth and development of plant crops,edible fungus,and livestock,and enhance the tolerance of these agriculturally important organisms against abiotic and biotic stresses.Even more importantly,H2 can regulate the growth and development of crops by changing the soil microbial community composition and structure.Use of H2 can also improve the nutritional value and postharvest quality of agricultural products.Researchers have also shown that the biological functions of molecular hydrogen are mediated by modulating reactive oxygen species(ROS),nitric oxide(NO),and carbon monoxide(CO)signaling cascades in plants and microbes.This review summarizes and clarifies the history of hydrogen agronomy and describes recent progress in the field.We also argue that emerging hydrogen agriculture will be an important direction in the new agriculture.Further,we discuss several scientific problems in hydrogen agronomy,and suggest that the future of hydrogen agronomy depends on contributions by multiple disciplines.Important future research directions of hydrogen agronomy include hydrogen agriculture in special environments,such as islands,reefs,aircraft,and outer space.
基金The authors wish to express thanks to National Natural Science Foundation of China(Grant No.51774154)the Jiangxi Natural Science Foundation(Grant No.20151BAB206029)for the financial support for this research。
文摘A novel technology,modified roasting in CO-CO2 mixed gas and magnetic separation,was presented to recover iron from copper slag.The effects of various parameters such as dosage of flux(CaO),gas flowrate of CO and CO2,roasting temperature,roasting time,particle size of modified slag and magnetic flux density on the oxidized modification and magnetic separation were investigated by comparison of the X-ray diffraction patterns and iron recovery ratio.The optimum conditions for recovering iron by oxidizing roasting and magnetic separation are as follows:calcium oxide content of 25 wt.%,mixed gas flow rates of CO2 and CO of 180 and 20 mL/min,oxidizing roasting at 1323 K for 2 h,grinding the modified slag to 38.5-25.0μm and magnetic separation at 170 mT.The mineralogical and microstructural characteristics of modified slag revealed that the iron-bearing minerals in the copper slag were oxidized,the generated magnetite grew into large particles,and the silicate in copper slag was combined with calcium oxide to form calcium silicate.Finally,the iron-bearing concentrate with an iron grade of 54.79%and iron recovery ratio of 80.14%was effectively obtained.
基金financial support from the National Basic Research Program of China(2015CB251201)the Fundamental Research Funds for the Central Universities(15CX06024A)the Program for Changjiang Scholars and Innovative Research Team in University(IRT1294 and IRT1086)
文摘CO2 flooding is regarded as an important method for enhanced oil recovery （EOR） and greenhouse gas control. However, the heterogeneity prevalently dis- tributed in reservoirs inhibits the performance of this technology. The sweep efficiency can be significantly reduced especially in the presence of ＂thief zones＂. Hence, gas channeling blocking and mobility control are important technical issues for the success of CO2 injection. Normally, crosslinked gels have the potential to block gas channels, but the gelation time control poses challenges to this method. In this study, a new method for selectively blocking CO2 channeling is proposed, which is based on a type of CO2-sensitive gel system （modified polyacry- lamide-methenamine-resorcinol gel system） to form gel in situ. A CO2-sensitive gel system is when gelation or solidification will be triggered by CO2 in the reservoir to block gas channels. The CO2-sensitivity of the gel system was demonstrated in parallel bottle tests of gel in N2 and CO2 atmospheres. Sand pack flow experiments were con- ducted to investigate the shutoff capacity of the gel system under different conditions. The injectivity of the gel system was studied via viscosity measurements. The results indi- cate that this gel system was sensitive to CO2 and had good performance of channeling blocking in porous media. Advantageous viscosity-temperature characteristics were achieved in this work. The effectiveness for EOR in heterogeneous formations based on this gel system was demonstrated using displacement tests conducted in double sand packs. The experimental results can provide guideli- nes for the deployment of theCO2-sensitive gel system for field applications.
