Electrochemical water splitting is a feasible method for producing environmental benignity energy of hydrogen,while high price and low availability on the earth of noble electrocatalysts constrain their global-scale a...Electrochemical water splitting is a feasible method for producing environmental benignity energy of hydrogen,while high price and low availability on the earth of noble electrocatalysts constrain their global-scale application.Transition metal borides(TMBs)have displayed unique metalloid characteristic and outstanding performance for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in the last few decades.Herein,recent developments of the TMBs for HER and OER are summarized.Initially,the impact factors and relevant evaluation of electrocatalytic performance are described,that is,overpotential,Tafel slope and exchange current density,stability,faradaic efficiency,turnover frequency,mass and specific activities.Moreover,the optimization strategies of borides are emphasized,which principally include coupling with effective substrates,elemental doping,phase modification,interfacial engineering,and morphology control.Finally,in order to reach the goal of application,the remaining challenges and perspectives are given to point out a direction for enhancing the performance of borides.展开更多
As a typical compatible solute, proline is accumulated in plants under environmental stresses. Proline transporter(Pro T) plays an important role in proline distribution between plant organs. Using a candidate gene ap...As a typical compatible solute, proline is accumulated in plants under environmental stresses. Proline transporter(Pro T) plays an important role in proline distribution between plant organs. Using a candidate gene approach, we cloned a c DNA sequence for Pro T from common bean(Phaseolus vulgaris L.) and designated the gene Pv Pro T. The deduced amino acid sequence of Pv Pro T showed high similarity to Bet/Pro T proteins from other leguminous plants, and the highest similarity was observed with mothbean(Vigna aconitifolia L.) Vu Pro T.Relative quantification of the m RNA level of Pv Pro T using real-time PCR analysis showed that the Pv Pro T transcript level was higher in leaves than in stems and roots of common bean plants subjected to drought and salt stress. Under 20%(w/w) PEG-6000 treatment,drought-resistant plants expressed a higher level of Pv Pro T transcripts than droughtsensitive plants. Although heterologous expression of Pv Pro T in the Escherichia coli mutant mkh13 showed that Pv Pro T exhibited uptake activities for proline and betaine, no betaine content was detected in the common bean. These findings suggest that Pv Pro T plays an important role in the transportation of proline in common bean plants exposed to drought and salt stress.展开更多
The distribution of adsorbent particle sizes typically has a significant impact on adsorption performance.Most fixed-bed adsorption studies adopt the assumption of average particle size to simplify the adsorption mode...The distribution of adsorbent particle sizes typically has a significant impact on adsorption performance.Most fixed-bed adsorption studies adopt the assumption of average particle size to simplify the adsorption model,but this does not eliminate the deviation between experiments and simulations caused by particle size distribution in practice.In this study,the population balance equation(PBE)and fixed-bed adsorption kinetics model were combined to simulate the adsorption process in a fixed-bed reactor,modeling the distribution of adsorbate uptake over time on adsorbent particles of different sizes.We integrated and optimized the PBE and fixed-bed mass transfer model in the algorithm,and the resulting combined model adopts a variable time step size,which can achieve a balance between computational efficiency and error while ensuring computational convergence.By slicing the model in the spatial dimension,multiple sets of PBE can be calculated in parallel,improving computational efficiency.The adsorption process of single-component and multi-component CO_(2)/CH_(4)/N_(2)on 4A zeolite without binder was simulated,and the influence of adsorbent particle size distribution was analyzed.Simulation results show that the assumption of average adsorbent particle size,which was commonly made in published work,will underestimate the time required for adsorbates to break through the fixed bed compared with the assumption of uniform adsorbent particle size.This model helps to consider the impact of adsorbent particle size distribution on the adsorption process,thereby improving the prediction accuracy of adsorbent performance.展开更多
基金supported by the National Natural Science Foundation of China(52025013,51622102)Ministry of Science and Technology of China MOST(2018YFB1502101)+1 种基金the 111 Project(B12015)the Fundamental Research Funds for the Central Universities.
文摘Electrochemical water splitting is a feasible method for producing environmental benignity energy of hydrogen,while high price and low availability on the earth of noble electrocatalysts constrain their global-scale application.Transition metal borides(TMBs)have displayed unique metalloid characteristic and outstanding performance for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in the last few decades.Herein,recent developments of the TMBs for HER and OER are summarized.Initially,the impact factors and relevant evaluation of electrocatalytic performance are described,that is,overpotential,Tafel slope and exchange current density,stability,faradaic efficiency,turnover frequency,mass and specific activities.Moreover,the optimization strategies of borides are emphasized,which principally include coupling with effective substrates,elemental doping,phase modification,interfacial engineering,and morphology control.Finally,in order to reach the goal of application,the remaining challenges and perspectives are given to point out a direction for enhancing the performance of borides.
基金supported by an earmarked fund for China Agriculture Research System (No. CARS-09)the Agricultural Science and Technology Innovation Program (ASTIP) of CAASthe Higher Education Institution Key Research Project Plan of Henan Province (No. 15A210042)
文摘As a typical compatible solute, proline is accumulated in plants under environmental stresses. Proline transporter(Pro T) plays an important role in proline distribution between plant organs. Using a candidate gene approach, we cloned a c DNA sequence for Pro T from common bean(Phaseolus vulgaris L.) and designated the gene Pv Pro T. The deduced amino acid sequence of Pv Pro T showed high similarity to Bet/Pro T proteins from other leguminous plants, and the highest similarity was observed with mothbean(Vigna aconitifolia L.) Vu Pro T.Relative quantification of the m RNA level of Pv Pro T using real-time PCR analysis showed that the Pv Pro T transcript level was higher in leaves than in stems and roots of common bean plants subjected to drought and salt stress. Under 20%(w/w) PEG-6000 treatment,drought-resistant plants expressed a higher level of Pv Pro T transcripts than droughtsensitive plants. Although heterologous expression of Pv Pro T in the Escherichia coli mutant mkh13 showed that Pv Pro T exhibited uptake activities for proline and betaine, no betaine content was detected in the common bean. These findings suggest that Pv Pro T plays an important role in the transportation of proline in common bean plants exposed to drought and salt stress.
基金the National Natural Science Foundation of China (21706075)Guangzhou Municipal Science and Technology Project (202201011269)
文摘The distribution of adsorbent particle sizes typically has a significant impact on adsorption performance.Most fixed-bed adsorption studies adopt the assumption of average particle size to simplify the adsorption model,but this does not eliminate the deviation between experiments and simulations caused by particle size distribution in practice.In this study,the population balance equation(PBE)and fixed-bed adsorption kinetics model were combined to simulate the adsorption process in a fixed-bed reactor,modeling the distribution of adsorbate uptake over time on adsorbent particles of different sizes.We integrated and optimized the PBE and fixed-bed mass transfer model in the algorithm,and the resulting combined model adopts a variable time step size,which can achieve a balance between computational efficiency and error while ensuring computational convergence.By slicing the model in the spatial dimension,multiple sets of PBE can be calculated in parallel,improving computational efficiency.The adsorption process of single-component and multi-component CO_(2)/CH_(4)/N_(2)on 4A zeolite without binder was simulated,and the influence of adsorbent particle size distribution was analyzed.Simulation results show that the assumption of average adsorbent particle size,which was commonly made in published work,will underestimate the time required for adsorbates to break through the fixed bed compared with the assumption of uniform adsorbent particle size.This model helps to consider the impact of adsorbent particle size distribution on the adsorption process,thereby improving the prediction accuracy of adsorbent performance.
