Novel ordered intermetallic compounds have stimulated much interest.Ru–Al alloys are a prominent class of hightemperature structural materials,but the experimentally reported crystal structure of the intermetallic Ru...Novel ordered intermetallic compounds have stimulated much interest.Ru–Al alloys are a prominent class of hightemperature structural materials,but the experimentally reported crystal structure of the intermetallic Ru_(2)Al_(5) phase remains elusive and debatable.To resolve this controversy,we extensively explored the crystal structures of Ru_(2)Al_(5) using first-principles calculations combined with crystal structure prediction technique.Among the calculated x-ray diffraction patterns and lattice parameters of five candidate Ru2Al5structures,those of the orthorhombic Pmmn structure best aligned with recent experimental results.The structural stabilities of the five Ru_(2)Al_(5)structures were confirmed through formation energy,elastic constants,and phonon spectrum calculations.We also comprehensively analyzed the mechanical and electronic properties of the five candidates.This work can guide the exploration of novel ordered intermetallic compounds in Ru–Al alloys.展开更多
Efficient bifunctional oxygen electrocatalysts for ORR and OER are fundamental to the development of high performance metal-air batteries.Herein,a facile cost-efficient two-step pyrolysis strategy for the fabrication ...Efficient bifunctional oxygen electrocatalysts for ORR and OER are fundamental to the development of high performance metal-air batteries.Herein,a facile cost-efficient two-step pyrolysis strategy for the fabrication of a bifunctional oxygen electrocatalyst has been proposed.The efficient non-preciousmetal-based electrocatalyst,Fe/Fe_(3)C@Fe-N_(x)-C consists of highly curved onion-like carbon shells that encapsulate Fe/Fe_(3)C nanoparticles,distributed on an extensively porous graphitic carbon aerogel.The obtained Fe/Fe_(3)C@Fe-N_(x)-C aerogel exhibited superb electrochemical activity,excellent durability,and high methanol tolerance.The experimental results indicated that the assembly of onion-like carbon shells with encapsulated Fe/Fe_(3)C yielded highly curved carbon surfaces with abundant Fe-Nxactive sites,a porous structure,and enhanced electrocatalytic activity towards ORR and OER,hence displaying promising potential for application as an air cathode in rechargeable Zn-air batteries.The constructed Zn-air battery possessed an exceptional peak power density of~147 mW cm^(-2),outstanding cycling stability(200 cycles,1 h per cycle),and a small voltage gap of 0.87 V.This study offers valuable insights regarding the construction of low-cost and highly active bifunctional oxygen electrocatalysts for efficient air batteries.展开更多
Catalytic oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have garnered great attention as the key character in metal-air batteries.Herein,we developed a superior nonprecious bifunctional oxygen electr...Catalytic oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have garnered great attention as the key character in metal-air batteries.Herein,we developed a superior nonprecious bifunctional oxygen electrocatalyst,fabricated through spatial confinement of Fe/Fe_(3)C nanocrystals in pyridinic N and Fe-Nx rich carbon nanotubes(Fe/Fe_(3)C-N-CNTs).During ORR,the resultant electrocatalyst exhibits positive onset pote ntial of 1.0 V(vs.RHE),large half-wave potentials of 0.88 V(vs.RHE),which is more positive than Pt/C(0.98 V and 0.83 V,respectively).Remarkably,Fe/Fe_(3)C-N-CNTs exhibits outstanding durability and great methanol tolerance,exceeding Pt/C and most reported nonprecious metal-based oxygen reduction electrocatalysts.Moreover,Fe/Fe_(3)C-N-CNTs show a markedly low potential at j=10 mA/cm^(2),small Tafel slopes and extremely high stability for OER.Impressively,the Fe/Fe_(3)C-N-CNTs-based Zn-air batteries demonstrate high power density of 183 mW/cm^(2)and robust charge/discharge stability.It is revealed that the spatial confinement effect can impede the aggregation and corrosion of Fe/Fe_(3)C nanocrystals.Meanwhile,Fe/Fe_(3)C and Fe-Nx play synergistic effect on boosting the ORR/OER activity,which provides an important guideline for construction of inexpensive nonprecious metal-carbon hybrid nanomaterials.展开更多
Organic electrosynthesis as an emerging green and advantageous alternative to traditional synthetic methods has achieved remarkable progress in recent years because sustainable electricity can be employed as traceless...Organic electrosynthesis as an emerging green and advantageous alternative to traditional synthetic methods has achieved remarkable progress in recent years because sustainable electricity can be employed as traceless redox agents. To surmount the over-oxidation/reduction issues of direct electrolysis,mediated or indirect electrochemical processes are attaining remarkable significance and promoting the selectivity of products. Molecular electrocatalysts, benefiting from the easily electronic and steric modulation, suffers from readily degradation issue in most cases. Remarkably, heterogeneous catalysts have drawn more attention due to their high activity, stability, and recyclability. Hence, in this review, the most recent growth of heterogeneous catalysts modified electrodes for organic electrosynthesis were summarized, highlighting structural optimization and electrochemical performance of these materials as well as reaction mechanism. Furthermore, key challenges and future directions in this area were also discussed.展开更多
Unraveling the distribution of metabolites in traditional Chinese medicine(TCM)provides direct indications for understanding their regulatory and functional basis,which is of paramount significance for better utilizat...Unraveling the distribution of metabolites in traditional Chinese medicine(TCM)provides direct indications for understanding their regulatory and functional basis,which is of paramount significance for better utilization and quality control of medicinal plants[1].Recently,imaging techniques such as near-infrared spectroscopy,Raman spectroscopy,and mass spectrometry(MS)were explored to reveal the spatial context of component accumulation and localization[2,3].展开更多
Starting from the basic equations describing the evolution of the carriers and photons inside a semiconductor optical amplifier （SOA）, the equation governing pulse propagation in the SOA is derived. By employing hom...Starting from the basic equations describing the evolution of the carriers and photons inside a semiconductor optical amplifier （SOA）, the equation governing pulse propagation in the SOA is derived. By employing homotopy analysis method （HAM）, a series solution for the output pulse by the SOA is obtained, which can effectively characterize the temporal features of the nonlinear process during the pulse propagation inside the SOA. Moreover, the analytical solution is compared with numerical simulations with a good agreement. The theoretical results will benefit the future analysis of other problems related to the pulse propagation in the SOA.展开更多
Chinese calligraphy,as a well-known performing art form,occupies an important role in the intangible cultural heritage of China.Previous studies focused on the psychophysiological benefits of Chinese calligraphy.Littl...Chinese calligraphy,as a well-known performing art form,occupies an important role in the intangible cultural heritage of China.Previous studies focused on the psychophysiological benefits of Chinese calligraphy.Little attention has been paid to its aesthetic attributes and effectiveness on the cognitive process.To complement our understanding of Chinese calligraphy,this study investigated the aesthetic experience of Chinese cursive-style calligraphy using brain functional network analysis.Subjects stayed on the coach and rested for several minutes.Then,they were requested to appreciate artwork of cursive-style calligraphy.Results showed that(1)changes in functional connectivity between frontooccipital,fronto-parietal,bilateral parietal,and central–occipital areas are prominent for calligraphy condition,(2)brain functional network showed an increased normalized cluster coefficient for calligraphy condition in alpha2 and gamma bands.These results demonstrate that the brain functional network undergoes a dynamic reconfiguration during the aesthetic experience of Chinese calligraphy.Providing evidence that the aesthetic experience of Chinese calligraphy has several similarities with western art while retaining its unique characters as an eastern traditional art form.展开更多
We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds ...We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.展开更多
Herein,we reported an electrochemical dehydrogenative homo-/cross-coupling of weakly activated naphthalene in the exogenous transition metal-and oxidants-free manner.Benefiting from the microscopic interaction between...Herein,we reported an electrochemical dehydrogenative homo-/cross-coupling of weakly activated naphthalene in the exogenous transition metal-and oxidants-free manner.Benefiting from the microscopic interaction between the reactants and the carbon plate anode,the electropolymerization of aromatic rings was suppressed.And a series of binaphthyl and naphthalene-aryl privileged scaffolds were obtained in 28%–90%yields by homo-or cross-coupling.This C(sp2)-H activation strategy featured atom and step economy as well as the ready scalability.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11965005 and 11964026)the Natural Science Basic Research Plan in Shaanxi Province,China(Grant Nos.2023-JC-YB-021 and 2022JM-035)+1 种基金the Fundamental Research Funds for the Central Universitiesthe 111 Project(Grant No.B17035)。
文摘Novel ordered intermetallic compounds have stimulated much interest.Ru–Al alloys are a prominent class of hightemperature structural materials,but the experimentally reported crystal structure of the intermetallic Ru_(2)Al_(5) phase remains elusive and debatable.To resolve this controversy,we extensively explored the crystal structures of Ru_(2)Al_(5) using first-principles calculations combined with crystal structure prediction technique.Among the calculated x-ray diffraction patterns and lattice parameters of five candidate Ru2Al5structures,those of the orthorhombic Pmmn structure best aligned with recent experimental results.The structural stabilities of the five Ru_(2)Al_(5)structures were confirmed through formation energy,elastic constants,and phonon spectrum calculations.We also comprehensively analyzed the mechanical and electronic properties of the five candidates.This work can guide the exploration of novel ordered intermetallic compounds in Ru–Al alloys.
基金supported financially by the National Natural Science Foundation of China,China(Grant No.51702180,51572136,91963113,21703116,51372127,51873096)The Scientific and Technical Development Project of Qingdao,China(Grant No.18-2-2-52-jch)+1 种基金The Taishan Scholar Advantage and Characteristic Discipline Team of Eco Chemical Process and TechnologyThe Natural Science Foundation of Hebei Province(B2019204009)。
文摘Efficient bifunctional oxygen electrocatalysts for ORR and OER are fundamental to the development of high performance metal-air batteries.Herein,a facile cost-efficient two-step pyrolysis strategy for the fabrication of a bifunctional oxygen electrocatalyst has been proposed.The efficient non-preciousmetal-based electrocatalyst,Fe/Fe_(3)C@Fe-N_(x)-C consists of highly curved onion-like carbon shells that encapsulate Fe/Fe_(3)C nanoparticles,distributed on an extensively porous graphitic carbon aerogel.The obtained Fe/Fe_(3)C@Fe-N_(x)-C aerogel exhibited superb electrochemical activity,excellent durability,and high methanol tolerance.The experimental results indicated that the assembly of onion-like carbon shells with encapsulated Fe/Fe_(3)C yielded highly curved carbon surfaces with abundant Fe-Nxactive sites,a porous structure,and enhanced electrocatalytic activity towards ORR and OER,hence displaying promising potential for application as an air cathode in rechargeable Zn-air batteries.The constructed Zn-air battery possessed an exceptional peak power density of~147 mW cm^(-2),outstanding cycling stability(200 cycles,1 h per cycle),and a small voltage gap of 0.87 V.This study offers valuable insights regarding the construction of low-cost and highly active bifunctional oxygen electrocatalysts for efficient air batteries.
基金supported financially by the National Natural Science Foundation of China(Nos.51702180,21703116,91963113,51372127)The Scientific and Technical Development Project of Qingdao,China(No.18-2-2-52-jch)The Taishan Scholar Advantage and Characteristic Discipline Team of Eco Chemical Process and Technology。
文摘Catalytic oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have garnered great attention as the key character in metal-air batteries.Herein,we developed a superior nonprecious bifunctional oxygen electrocatalyst,fabricated through spatial confinement of Fe/Fe_(3)C nanocrystals in pyridinic N and Fe-Nx rich carbon nanotubes(Fe/Fe_(3)C-N-CNTs).During ORR,the resultant electrocatalyst exhibits positive onset pote ntial of 1.0 V(vs.RHE),large half-wave potentials of 0.88 V(vs.RHE),which is more positive than Pt/C(0.98 V and 0.83 V,respectively).Remarkably,Fe/Fe_(3)C-N-CNTs exhibits outstanding durability and great methanol tolerance,exceeding Pt/C and most reported nonprecious metal-based oxygen reduction electrocatalysts.Moreover,Fe/Fe_(3)C-N-CNTs show a markedly low potential at j=10 mA/cm^(2),small Tafel slopes and extremely high stability for OER.Impressively,the Fe/Fe_(3)C-N-CNTs-based Zn-air batteries demonstrate high power density of 183 mW/cm^(2)and robust charge/discharge stability.It is revealed that the spatial confinement effect can impede the aggregation and corrosion of Fe/Fe_(3)C nanocrystals.Meanwhile,Fe/Fe_(3)C and Fe-Nx play synergistic effect on boosting the ORR/OER activity,which provides an important guideline for construction of inexpensive nonprecious metal-carbon hybrid nanomaterials.
基金the financial support from the National Natural Science Foundation of China (No. 22171154)the Youth Innovative Talents Recruitment and Cultivation Program of Shandong Higher Education+2 种基金the Natural Science Foundation of Shandong Province (Nos. ZR^(2)020QB114, ZR^(2)020QB008 and ZR^(2)019BB031)Jinan Science&Technology Bureau (No. 2021GXRC080)The project supported by the Foundation (No. ZZ20190312) of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology (Shandong Academy of Sciences)。
文摘Organic electrosynthesis as an emerging green and advantageous alternative to traditional synthetic methods has achieved remarkable progress in recent years because sustainable electricity can be employed as traceless redox agents. To surmount the over-oxidation/reduction issues of direct electrolysis,mediated or indirect electrochemical processes are attaining remarkable significance and promoting the selectivity of products. Molecular electrocatalysts, benefiting from the easily electronic and steric modulation, suffers from readily degradation issue in most cases. Remarkably, heterogeneous catalysts have drawn more attention due to their high activity, stability, and recyclability. Hence, in this review, the most recent growth of heterogeneous catalysts modified electrodes for organic electrosynthesis were summarized, highlighting structural optimization and electrochemical performance of these materials as well as reaction mechanism. Furthermore, key challenges and future directions in this area were also discussed.
基金supported by the National Natural Science Foundation of China(Grant No.:81773874).
文摘Unraveling the distribution of metabolites in traditional Chinese medicine(TCM)provides direct indications for understanding their regulatory and functional basis,which is of paramount significance for better utilization and quality control of medicinal plants[1].Recently,imaging techniques such as near-infrared spectroscopy,Raman spectroscopy,and mass spectrometry(MS)were explored to reveal the spatial context of component accumulation and localization[2,3].
基金This work was supported in part by the National Natural Science Foundation of China （Grant No. 61106062）, the Scientific Research Fund of Shaanxi Provincial Education Department （Grant No. 16JK1016）, and the project of Anakang University （Grant No. 2017AYQN06）.
文摘Starting from the basic equations describing the evolution of the carriers and photons inside a semiconductor optical amplifier （SOA）, the equation governing pulse propagation in the SOA is derived. By employing homotopy analysis method （HAM）, a series solution for the output pulse by the SOA is obtained, which can effectively characterize the temporal features of the nonlinear process during the pulse propagation inside the SOA. Moreover, the analytical solution is compared with numerical simulations with a good agreement. The theoretical results will benefit the future analysis of other problems related to the pulse propagation in the SOA.
基金the National Natural Science Foundation of China(Grant No.61772440,Grant No.62007016).
文摘Chinese calligraphy,as a well-known performing art form,occupies an important role in the intangible cultural heritage of China.Previous studies focused on the psychophysiological benefits of Chinese calligraphy.Little attention has been paid to its aesthetic attributes and effectiveness on the cognitive process.To complement our understanding of Chinese calligraphy,this study investigated the aesthetic experience of Chinese cursive-style calligraphy using brain functional network analysis.Subjects stayed on the coach and rested for several minutes.Then,they were requested to appreciate artwork of cursive-style calligraphy.Results showed that(1)changes in functional connectivity between frontooccipital,fronto-parietal,bilateral parietal,and central–occipital areas are prominent for calligraphy condition,(2)brain functional network showed an increased normalized cluster coefficient for calligraphy condition in alpha2 and gamma bands.These results demonstrate that the brain functional network undergoes a dynamic reconfiguration during the aesthetic experience of Chinese calligraphy.Providing evidence that the aesthetic experience of Chinese calligraphy has several similarities with western art while retaining its unique characters as an eastern traditional art form.
基金the National Natural Science Foundation of China(Nos.22171154 and 21801144)the Youth Innovative Talents Recruitment and Cultivation Program of Shandong Higher Education,the Natural Science Foundation of Shandong Province(Nos.ZR2020QB114 and ZR2020QB008)+4 种基金Jinan Science&Technology Bureau(No.2021GXRC080)supported by the Foundation(No.ZZ20190312)of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology(Shandong Academy of Sciences)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province,the Open Fund of the Department of Chemistry,Qingdao University of Science and Technology(No.QUSTHX202010)Science and Technology Innovation Development Plan of Yantai(No.2020MSGY114)Yantai“Double Hundred Plan”.
文摘We demonstrated herein an electrochemical dearomatizative alkylation of Katritzky salts,wherein Katritzky salts were harnessed as both radical acceptors and donors.A wide range of privileged dihydropyridine scaffolds was constructed with good to excellent yields.Cyclic voltammetry(CV)and electron paramagnetic resonance(EPR)results confirmed the key intermediates-dihydropyridine radicals and gram-scale reaction highlighted the practical and sustainable feature of the newly developed protocol.
基金We greatly appreciate the financial support from the National Natural Science Foundation of China(Nos.22171154 and 21801144)the Youth Innovative Talents Recruitment and Cultivation Program of Shandong Higher Education,the Natural Science Foundation of Shandong Province(Nos.ZR2020QB114 and ZR2020QB008)+2 种基金Jinan Science&Technology Bureau(No.2021GXRC080)The project is supported by the Foundation of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology(Shandong Academy of Sciences)(No.ZZ20190312)the Program for Scientific Research Innovation Team in Colleges and Universities of Shandong Province,the Open Fund of the Department of Chemistry,Qingdao University of Science and Technology(No.QUSTHX202010).
文摘Herein,we reported an electrochemical dehydrogenative homo-/cross-coupling of weakly activated naphthalene in the exogenous transition metal-and oxidants-free manner.Benefiting from the microscopic interaction between the reactants and the carbon plate anode,the electropolymerization of aromatic rings was suppressed.And a series of binaphthyl and naphthalene-aryl privileged scaffolds were obtained in 28%–90%yields by homo-or cross-coupling.This C(sp2)-H activation strategy featured atom and step economy as well as the ready scalability.
