Developing nonprecious metal-nitrogen-doped carbon(M-N-C)catalysts with high activity and stability is critical to their widespread use in fuel cells;however,these catalysts still face considerable challenges.Herein,a...Developing nonprecious metal-nitrogen-doped carbon(M-N-C)catalysts with high activity and stability is critical to their widespread use in fuel cells;however,these catalysts still face considerable challenges.Herein,a novel iron atom-cluster strategy for the synthesis of iron-based N-C catalyst comprising Fe nanoparticles(Fe NPs)surrounded by Fe-N_(x) sites is developed for oxygen reduction reactions in an acidic fuel cell.Iron oxide NPs were incorporated into zeolitic imidazolate framework-8(ZIF-8)-derived carbon materials and pyrolyzed at high temperatures using NaCl as a modifi er to produce Fe NPs and Fe-N_(x) composite active sites.The half-wave potential of the optimized Fe_(NP)/FeNC-NaCl material was substantially improved to 0.81 V.Furthermore,even after 15,000 cycles,the half-wave potential of the catalyst remained essentially unchanged.As a cathode catalyst for fuel cells,it realized a high peak power density of 436 mW/cm^(2)under a practical H_(2)-air atmosphere.Therefore,this study presents a new approach for designing and synthesizing electrocatalytic materials with high catalytic activity and stability.展开更多
[Objectives]The research aimed to explore the distribution characteristics of TCM constitution types of patients with hypertension and insomnia,and study the clinical characteristics of patients with different constit...[Objectives]The research aimed to explore the distribution characteristics of TCM constitution types of patients with hypertension and insomnia,and study the clinical characteristics of patients with different constitutions,in order to provide new ideas for the treatment of patients with hypertension and insomnia.[Methods]Cross sectional observation method was used,and 420 patients with hypertension and insomnia were selected.Required information was collected,and the constitution type of traditional Chinese medicine was determined,and relevant data were recorded.SPSS and Logistic regression analysis method were used to explore the correlation between the distribution of TCM constitution types and gender,age,24 h-SBP,24 h-DBP,24 h-BPV,PSQI score,etc.[Results]Among 420 patients,the proportion of gentleness constitution was the most,and others in turn were Qi deficiency constitution>Yang deficiency constitution>phlegm dampness constitution>Qi stagnation constitution>Yin deficiency constitution>blood stasis constitution>damp heat constitution>special constitution.Among male patients,the proportion of gentleness constitution was the most.Among female patients,the proportion of Qi deficiency constitution was the most.In each constitution,the proportion of men and women was different,and the difference in gentleness constitution,Qi deficiency constitution and Yin deficiency constitution had statistical significance(P<0.05).The proportion of gentleness constitution for young and middle-aged patients was the most,while elderly patients with Qi deficiency constitution was the most.There was difference in the distribution of TCM constitution in different age groups,and the difference had statistical significance(P<0.05).Compared with the patients with gentleness constitution,the patients with Qi deficiency constitution,Yang deficiency constitution,Yin deficiency constitution,damp heat constitution,blood stasis constitution and Qi stagnation constitution had different differences in terms of age,24 h-SBP,24 h-DBP,24 h-BPV and PSQI score,and there was statistical significance(P<0.05).Except damp heat constitution,blood stasis constitution and special constitution,other constitutions had certain correlation with age,24 h-SBP,24 h-DBP,24 h-BPV and PSQI score.[Conclusions]TCM constitution types of patients with hypertension and insomnia were dominant by gentleness constitution,Qi deficiency constitution and Yang deficiency constitution.The distribution of TCM constitution in different gender and age groups was different,and different TCM constitution was related to ABPM and PSQI.展开更多
Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane f...Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane fuel cells(PEMFCs)due to their higher active surface area and adjustable D-band energy levels compared to Pt/C.However,how to balance the alloying degree and ORR performance of Pt-Co catalyst remains a great challenge.Herein,we first synthesized a well-dispersed Pt/Co/C precursor by using a mild dimethylamine borane(DMAB)as the reducing agent.The precursor was calcined at high temperature under H_(2)/Ar mixed gas by a secondary reduction strategy to obtain an ordered Pt_(3)Co intermetallic compound nanoparticle catalyst with a high degree of alloying.The optimization of elec-tronic structure due to Pt-Co alloying and the strong metal-carrier interaction ensure the high kinetic activity of the cell membrane electrode.Additionally,the high degree of graphitization increases the electrical conductivity during the reaction.As a result,the activity and stability of the catalyst were significantly improved,with a half-wave potential as high as 0.87 V,which decreased by only 20 mV after 10000 potential cycles.Single-cell tests further validate the high intrinsic activity of the ordered Pt_(3)Co catalyst with mass activity up to 0.67 A mg_(pt)^(-1),exceeding the United States Department of Energy(US DOE)standard(0.44 A mg_(pt)^(-1)),and a rated power of 5.93 W mg_(pt)^(-1).展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFB3807500)the Natural Science Foundation of China(No.22220102003)+1 种基金the Beijing Natural Science Foundation(No.JL23003)“Double-First-Class”Construction Projects(Nos.XK180301,XK1804-02).
文摘Developing nonprecious metal-nitrogen-doped carbon(M-N-C)catalysts with high activity and stability is critical to their widespread use in fuel cells;however,these catalysts still face considerable challenges.Herein,a novel iron atom-cluster strategy for the synthesis of iron-based N-C catalyst comprising Fe nanoparticles(Fe NPs)surrounded by Fe-N_(x) sites is developed for oxygen reduction reactions in an acidic fuel cell.Iron oxide NPs were incorporated into zeolitic imidazolate framework-8(ZIF-8)-derived carbon materials and pyrolyzed at high temperatures using NaCl as a modifi er to produce Fe NPs and Fe-N_(x) composite active sites.The half-wave potential of the optimized Fe_(NP)/FeNC-NaCl material was substantially improved to 0.81 V.Furthermore,even after 15,000 cycles,the half-wave potential of the catalyst remained essentially unchanged.As a cathode catalyst for fuel cells,it realized a high peak power density of 436 mW/cm^(2)under a practical H_(2)-air atmosphere.Therefore,this study presents a new approach for designing and synthesizing electrocatalytic materials with high catalytic activity and stability.
基金the National Key R&D Program Funded Project(2018 YFC17056009)Study on Insomnia and Its Relationship with Climacteric Syndrome,Hypertension,Mild Cognitive Impairment in the Elderly and Comprehensive Treatment Plan(2018YFC1705604)Pilot Project of Clinical Cooperation between Traditional Chinese and Western Medicine for Major and Difficult Diseases by the State Administration of Traditional Chinese Medicine:"Refractory Hypertension"(GZYYBYZF[2018]3).
文摘[Objectives]The research aimed to explore the distribution characteristics of TCM constitution types of patients with hypertension and insomnia,and study the clinical characteristics of patients with different constitutions,in order to provide new ideas for the treatment of patients with hypertension and insomnia.[Methods]Cross sectional observation method was used,and 420 patients with hypertension and insomnia were selected.Required information was collected,and the constitution type of traditional Chinese medicine was determined,and relevant data were recorded.SPSS and Logistic regression analysis method were used to explore the correlation between the distribution of TCM constitution types and gender,age,24 h-SBP,24 h-DBP,24 h-BPV,PSQI score,etc.[Results]Among 420 patients,the proportion of gentleness constitution was the most,and others in turn were Qi deficiency constitution>Yang deficiency constitution>phlegm dampness constitution>Qi stagnation constitution>Yin deficiency constitution>blood stasis constitution>damp heat constitution>special constitution.Among male patients,the proportion of gentleness constitution was the most.Among female patients,the proportion of Qi deficiency constitution was the most.In each constitution,the proportion of men and women was different,and the difference in gentleness constitution,Qi deficiency constitution and Yin deficiency constitution had statistical significance(P<0.05).The proportion of gentleness constitution for young and middle-aged patients was the most,while elderly patients with Qi deficiency constitution was the most.There was difference in the distribution of TCM constitution in different age groups,and the difference had statistical significance(P<0.05).Compared with the patients with gentleness constitution,the patients with Qi deficiency constitution,Yang deficiency constitution,Yin deficiency constitution,damp heat constitution,blood stasis constitution and Qi stagnation constitution had different differences in terms of age,24 h-SBP,24 h-DBP,24 h-BPV and PSQI score,and there was statistical significance(P<0.05).Except damp heat constitution,blood stasis constitution and special constitution,other constitutions had certain correlation with age,24 h-SBP,24 h-DBP,24 h-BPV and PSQI score.[Conclusions]TCM constitution types of patients with hypertension and insomnia were dominant by gentleness constitution,Qi deficiency constitution and Yang deficiency constitution.The distribution of TCM constitution in different gender and age groups was different,and different TCM constitution was related to ABPM and PSQI.
基金supported by the National Key Research and Development Program of China(grant No.2022YFB3807500)the National Natural Science Foundation of China(grant No.21922802,22220102003)+1 种基金the Beijing Natural Science Foundation(grant No.JQ19007)“Double-First-Class”construction projects(grant No.XK180301,XK1804-02).
文摘Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane fuel cells(PEMFCs)due to their higher active surface area and adjustable D-band energy levels compared to Pt/C.However,how to balance the alloying degree and ORR performance of Pt-Co catalyst remains a great challenge.Herein,we first synthesized a well-dispersed Pt/Co/C precursor by using a mild dimethylamine borane(DMAB)as the reducing agent.The precursor was calcined at high temperature under H_(2)/Ar mixed gas by a secondary reduction strategy to obtain an ordered Pt_(3)Co intermetallic compound nanoparticle catalyst with a high degree of alloying.The optimization of elec-tronic structure due to Pt-Co alloying and the strong metal-carrier interaction ensure the high kinetic activity of the cell membrane electrode.Additionally,the high degree of graphitization increases the electrical conductivity during the reaction.As a result,the activity and stability of the catalyst were significantly improved,with a half-wave potential as high as 0.87 V,which decreased by only 20 mV after 10000 potential cycles.Single-cell tests further validate the high intrinsic activity of the ordered Pt_(3)Co catalyst with mass activity up to 0.67 A mg_(pt)^(-1),exceeding the United States Department of Energy(US DOE)standard(0.44 A mg_(pt)^(-1)),and a rated power of 5.93 W mg_(pt)^(-1).
