An intuitive portrayal of the correlation between the carbon and energy markets is essential for risk control and green financial investment management.In this paper,we investigate the asymmetric spillovers between th...An intuitive portrayal of the correlation between the carbon and energy markets is essential for risk control and green financial investment management.In this paper,we investigate the asymmetric spillovers between the carbon mar-ket and energy market returns.To achieve that,we improve the Diebold-Yilmaz index model by a time-varying vector autoregressive(TVP-VAR)model.In a unified network,our daily dataset includes the closing prices of the Hubei carbon market,Shenzhen carbon market,coal futures,and energy stock index.The findings reveal that both the Hubei and Shen-zhen pilots typically generate net information spillovers on energy futures.In connection with energy stocks,the Hubei carbon market acts as a net receiver,while the Shenzhen carbon market is a net transmitter.Compared with the Hubei pi-lot,the Shenzhen pilot is more tightly connected to the energy markets.Furthermore,the spillovers of the carbon markets exhibit significant asymmetry.In most cases,they have more substantial impacts on the energy markets when the prices of emission allowances rise.The direction and magnitude of asymmetric spillovers across markets vary over time and can be influenced by certain economic or political events.展开更多
Research has been conducted about the hardness prediction for the carburizing and quenching process based on an optimized hardness simulation model,in accordance with the calculation rule of mixed phases.The coupling ...Research has been conducted about the hardness prediction for the carburizing and quenching process based on an optimized hardness simulation model,in accordance with the calculation rule of mixed phases.The coupling field model incorporates carburizing field analysis,temperature field analysis,phase transformation kinetics analysis and a modified hardness calculation model.In determination of the calculation model for hardness,calculation equations are given to be applied to low carbon content(x(C)<0.5%) for the child phases and the martensite hardness is calculated for high carbon content(x(C)>0.5%) in alloy.Then,the complete carburizing-quenching hardness calculation model is built,and the hardness simulation data are corrected considering the influence of residual austenite(RA) on hardness.Hardness simulations of the carburizing and quenching process of 17CrNiMo6 samples have been performed using DEFORM-HT_V10.2 and MATLAB R2013 a.Finally,a series of comparisons of simulation results and measured values show a good agreement between them,which validates the accuracy of the proposed mathematical model.展开更多
A simplified model was developed to describe the water vapor adsorption on activated carbon. The development of the simplified model was started from the original model proposed by DO and his co-workers. Two different...A simplified model was developed to describe the water vapor adsorption on activated carbon. The development of the simplified model was started from the original model proposed by DO and his co-workers. Two different kinds of carbon materials were prepared for water vapor adsorption, and the adsorption experiments were conducted at different temperatures(20-50 °C) and relative humidities(5%-99%) to test the model. It is shown that the amount of adsorbed water vapor in micropore decreases with the temperature increasing, and the water molecules form larger water clusters around the functional group as the temperature is up to a higher value. The simplified model describes reasonably well for all the experimental data. According to the fitted values, the parameters of simplified model were represented by the temperature and then the model was used to calculate the water vapor adsorption amount at 25 °C and 35 °C. The results show that the model can get relatively accurate values to calculate the water vapor adsorption on activated carbon.展开更多
The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self...The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.展开更多
基金supported by the National Natural Science Foundation of China(71973001).
文摘An intuitive portrayal of the correlation between the carbon and energy markets is essential for risk control and green financial investment management.In this paper,we investigate the asymmetric spillovers between the carbon mar-ket and energy market returns.To achieve that,we improve the Diebold-Yilmaz index model by a time-varying vector autoregressive(TVP-VAR)model.In a unified network,our daily dataset includes the closing prices of the Hubei carbon market,Shenzhen carbon market,coal futures,and energy stock index.The findings reveal that both the Hubei and Shen-zhen pilots typically generate net information spillovers on energy futures.In connection with energy stocks,the Hubei carbon market acts as a net receiver,while the Shenzhen carbon market is a net transmitter.Compared with the Hubei pi-lot,the Shenzhen pilot is more tightly connected to the energy markets.Furthermore,the spillovers of the carbon markets exhibit significant asymmetry.In most cases,they have more substantial impacts on the energy markets when the prices of emission allowances rise.The direction and magnitude of asymmetric spillovers across markets vary over time and can be influenced by certain economic or political events.
基金Projects(51535012,U1604255)supported by the National Natural Science Foundation of ChinaProject(2016JC2001)supported by the Key Research and Development Program of Hunan Province,China
文摘Research has been conducted about the hardness prediction for the carburizing and quenching process based on an optimized hardness simulation model,in accordance with the calculation rule of mixed phases.The coupling field model incorporates carburizing field analysis,temperature field analysis,phase transformation kinetics analysis and a modified hardness calculation model.In determination of the calculation model for hardness,calculation equations are given to be applied to low carbon content(x(C)<0.5%) for the child phases and the martensite hardness is calculated for high carbon content(x(C)>0.5%) in alloy.Then,the complete carburizing-quenching hardness calculation model is built,and the hardness simulation data are corrected considering the influence of residual austenite(RA) on hardness.Hardness simulations of the carburizing and quenching process of 17CrNiMo6 samples have been performed using DEFORM-HT_V10.2 and MATLAB R2013 a.Finally,a series of comparisons of simulation results and measured values show a good agreement between them,which validates the accuracy of the proposed mathematical model.
基金Projects(21376274,51206192)supported by the National Natural Science Foundation of China
文摘A simplified model was developed to describe the water vapor adsorption on activated carbon. The development of the simplified model was started from the original model proposed by DO and his co-workers. Two different kinds of carbon materials were prepared for water vapor adsorption, and the adsorption experiments were conducted at different temperatures(20-50 °C) and relative humidities(5%-99%) to test the model. It is shown that the amount of adsorbed water vapor in micropore decreases with the temperature increasing, and the water molecules form larger water clusters around the functional group as the temperature is up to a higher value. The simplified model describes reasonably well for all the experimental data. According to the fitted values, the parameters of simplified model were represented by the temperature and then the model was used to calculate the water vapor adsorption amount at 25 °C and 35 °C. The results show that the model can get relatively accurate values to calculate the water vapor adsorption on activated carbon.
基金Project(2018YFC0705404)supported by the National Key Technology Research and Development of ChinaProjects(51878480,51678442,51878481,51878496)supported by the National Natural Science Foundation of China+1 种基金Project(U1534207)supported by the National High-speed Train Union Fund,ChinaProject supported by the Fundamental Research Funds for the Central Universities,China
文摘The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.
