Although signifi cant research eff orts have been targeted toward conservation and management of endangered terrestrial fl ora and fauna,attempts have been limited to conserve threatened seaweeds.Silvetia siliquosa is...Although signifi cant research eff orts have been targeted toward conservation and management of endangered terrestrial fl ora and fauna,attempts have been limited to conserve threatened seaweeds.Silvetia siliquosa is an ecologically and commercially vital brown alga that is uniquely distributed in the Yellow-Bohai Sea and along the southwest coast of Korea.A massive decline in its distribution range and biomass from the mid-1990s onward indicates that this species has become endangered.In the present study,we used nuclear internal transcribed spacer and concatenated mitochondrial cytochrome oxidase I subunit+intergenic spacer to estimate the genetic diversity,population connectivity,and degree of genetic diff erentiation of S.siliquosa in China and Korea.The molecular results exhibited strikingly low levels of haplotype/ribotype and nucleotide diversity in S.siliquosa populations,with only three mitochondrial haplotypes and nuclear ribotypes detected in 136 and 143 specimens,respectively.The analysis of molecular variance revealed 85%-95%of genetic variance among populations.Population diff erentiation coeffi cient(F_(ST))and gene fl ow(N_(m))suggested that two populations(JIN and GWA)along the southern coast of Korea are highly divergent from the others,with weak genetic exchange.No signifi cant genetic diff erentiation was observed among populations either in China or along the geographically proximate west coast of Korea.Thus,four independent management units were designated for sustainable management:the LII and RUS populations in China,the YEO and CHA populations along the west coast of Korea,and each of the GWA and JIN populations along the south coast of Korea.We suggest that artifi cial cultivation and transplantation of S.siliquosa are the eff ective approaches for restoration and conservation.展开更多
To investigate the effect of covID-19 control measures on aerosol chemistry,the chemical compositions,mixing states,and formation mechanisms of carbonaceous particles in the urban atmosphere of Liao-cheng in the North...To investigate the effect of covID-19 control measures on aerosol chemistry,the chemical compositions,mixing states,and formation mechanisms of carbonaceous particles in the urban atmosphere of Liao-cheng in the North China Plain(NCP)were compared before and during the pandemic using a single particle aerosol mass spectrometry(SPAMS).The results showed that the concentrations of five air pollutants including PM2.5,PM1o,SO2,NO2,and cO decreased by 41.2%-71.5%during the pandemic compared to those before the pandemic,whereas O3 increased by 1.3 times during the pandemic because of the depressed titration of O3 and more favorable meteorological conditions.The count and percentage contribution of carbonaceous particles in the total detected particles were lower during the pandemic than those before the pandemic.The carbonaceous particles were dominated by elemental and organic carbon(ECOC,35.9%),followed by elemental carbon-aged(EC-aged,19.6%)and organic carbon-fresh(OC-fresh,13.5%)before the pandemic,while EC-aged(25.3%),ECOC(17.9%),and secondary ions-rich(SEC,17.8%)became the predominant species during the pandemic.The carbonaceous particle sizes during the pandemic showed a broader distribution than that before the pandemic,due to the condensation and coagulation of carbonaceous particles in the aging processes.The relative aerosol acidity(Rra)was smaller before the pandemic than that during the pandemic,indicating the more acidic particle aerosol during the pandemic closely related to the secondary species and relative humidity(RH).More than 95.0%and 86.0%of carbonaceous particles in the whole period were internally mixed with nitrate and sulfate,implying that most of the carbonaceous particles were associated with secondary oxidation during their formation processes.The diurnal variations of oxalate particles and correlation analyses suggested that oxalate particles before the pandemic were derived from aqueous oxidation driven by RH and liquid water content(LwC),while oxalate particles during the pandemic were originated from O3-dominatedphotochemical oxidation.展开更多
Multifunctional catalysts that exhibit high catalytic performance for the hydrogen evolution reaction(HER),oxygen evolution reaction(OER),and oxygen reduction reaction(ORR)in a single material hold great promise for b...Multifunctional catalysts that exhibit high catalytic performance for the hydrogen evolution reaction(HER),oxygen evolution reaction(OER),and oxygen reduction reaction(ORR)in a single material hold great promise for broad-spectrum applications,including overall water splitting,fuel cells,and metal-air batteries.In this first-principles study,Cu_(3) N is computationally demonstrated as a multifunctional electrocatalyst for the HER,OER,and ORR owing to the unique coordination of N and Cu atoms on the(001)surface.Cu_(3) N exhibits better HER catalytic activity than noble Pt-based catalysts.Furthermore,its OER and ORR catalytic activity is comparable to that of commercialized unifunctional catalysts,and its 4e-pathway selectivity is high during the ORR.The catalytic performance of the ORR is significantly improved by the introduction of vacancy defects.The integration of highly efficient HER,OER,and ORR catalytic performance in earth-abundant Cu_(3) N not only opens an avenue for developing cost-efficient omnipotent catalysts but also facilitates advances in clean and renewable energy.展开更多
Two-dimensional(2 D)van der Waals materials have been widely adopted as photocatalysts for water splitting,but the energy conversion efficiency remains low.On the basis of first-principles calculations,we demonstrate ...Two-dimensional(2 D)van der Waals materials have been widely adopted as photocatalysts for water splitting,but the energy conversion efficiency remains low.On the basis of first-principles calculations,we demonstrate that the 2 D Janus group-Ⅲchalcogenide multilayers:In Ga XY,M2XY and In GaX2(M=In/Ga;X,Y=S/Se/Te),are promising photocatalysts for highly-efficient overall water splitting.The intrinsic electric field enhances the spatial separations of photogenerated carriers and alters the band alignment,which is more pronounced compared with the Janus monolayers.High solar-to-hydrogen(STH)efficiency with the upper limit of 38.5%was predicted in the Janus multilayers.More excitingly,the Ga vacancy of In Ga SSe bilayer effectively lowers the overpotentials of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)to the levels provided solely by the photogenerated carriers.Our theoretical results suggest that the 2 D Janus group-III chalcogenide multilayers could be utilized as highly efficient photocatalysts for overall water splitting without the needs of sacrificial reagents.展开更多
Multifunctional catalysts that integrate high efficiency hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR) catalytic activity in a single material are attractive for u...Multifunctional catalysts that integrate high efficiency hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR) catalytic activity in a single material are attractive for unitized regenerative fuel cells and overall water splitting technologies. As the best-known HER and ORR electrocatalysts, Pt and its alloys have only moderate OER activity. Ruthenium and iridium oxides exhibit the highest OER activities but not as active as Pt for HER and ORR. Here, we proposed a general principle for achieving trifunctional electrocatalysis for three reactions in a single material. Using the newly-synthesized pyrazine-modified graphdiyne(PR-GDY) as an example, we demonstrated that the synergistic effect of the pyridinic nitrogen and anchored transition-metal(TM) single atoms renders highly-efficient HER/OER/ORR trifunctional electrocatalytic activity. For the Ni-doped PR-GDY, the overpotentials for HER, OER and ORR can be respectively as low as -0.05, 0.29 and 0.38 V, which are comparable or even superior to the best-known single-functional and bi-functional precious electrocatalysts.These computational results offer not only a promising trifunctional electrocatalyst but also a strategy for the design of multifunctional electrocatalysts.展开更多
The asymmetric a-sulfenylation of Ni（II） complex of glycine with S-substituted 4-methylbenzenesulfonothioate is reported. Due to the mild and simple reaction conditions, this asymmetric reaction is compatible with v...The asymmetric a-sulfenylation of Ni（II） complex of glycine with S-substituted 4-methylbenzenesulfonothioate is reported. Due to the mild and simple reaction conditions, this asymmetric reaction is compatible with various functional groups.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.31971395,41761144057)。
文摘Although signifi cant research eff orts have been targeted toward conservation and management of endangered terrestrial fl ora and fauna,attempts have been limited to conserve threatened seaweeds.Silvetia siliquosa is an ecologically and commercially vital brown alga that is uniquely distributed in the Yellow-Bohai Sea and along the southwest coast of Korea.A massive decline in its distribution range and biomass from the mid-1990s onward indicates that this species has become endangered.In the present study,we used nuclear internal transcribed spacer and concatenated mitochondrial cytochrome oxidase I subunit+intergenic spacer to estimate the genetic diversity,population connectivity,and degree of genetic diff erentiation of S.siliquosa in China and Korea.The molecular results exhibited strikingly low levels of haplotype/ribotype and nucleotide diversity in S.siliquosa populations,with only three mitochondrial haplotypes and nuclear ribotypes detected in 136 and 143 specimens,respectively.The analysis of molecular variance revealed 85%-95%of genetic variance among populations.Population diff erentiation coeffi cient(F_(ST))and gene fl ow(N_(m))suggested that two populations(JIN and GWA)along the southern coast of Korea are highly divergent from the others,with weak genetic exchange.No signifi cant genetic diff erentiation was observed among populations either in China or along the geographically proximate west coast of Korea.Thus,four independent management units were designated for sustainable management:the LII and RUS populations in China,the YEO and CHA populations along the west coast of Korea,and each of the GWA and JIN populations along the south coast of Korea.We suggest that artifi cial cultivation and transplantation of S.siliquosa are the eff ective approaches for restoration and conservation.
基金supported by the National Natural Science Fund of China(grant number 42177083)Natural Science Foundation of Shandong Province(grant number ZR2020MD113)and Open Funds of State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences(grant number SKLLOG2020).
文摘To investigate the effect of covID-19 control measures on aerosol chemistry,the chemical compositions,mixing states,and formation mechanisms of carbonaceous particles in the urban atmosphere of Liao-cheng in the North China Plain(NCP)were compared before and during the pandemic using a single particle aerosol mass spectrometry(SPAMS).The results showed that the concentrations of five air pollutants including PM2.5,PM1o,SO2,NO2,and cO decreased by 41.2%-71.5%during the pandemic compared to those before the pandemic,whereas O3 increased by 1.3 times during the pandemic because of the depressed titration of O3 and more favorable meteorological conditions.The count and percentage contribution of carbonaceous particles in the total detected particles were lower during the pandemic than those before the pandemic.The carbonaceous particles were dominated by elemental and organic carbon(ECOC,35.9%),followed by elemental carbon-aged(EC-aged,19.6%)and organic carbon-fresh(OC-fresh,13.5%)before the pandemic,while EC-aged(25.3%),ECOC(17.9%),and secondary ions-rich(SEC,17.8%)became the predominant species during the pandemic.The carbonaceous particle sizes during the pandemic showed a broader distribution than that before the pandemic,due to the condensation and coagulation of carbonaceous particles in the aging processes.The relative aerosol acidity(Rra)was smaller before the pandemic than that during the pandemic,indicating the more acidic particle aerosol during the pandemic closely related to the secondary species and relative humidity(RH).More than 95.0%and 86.0%of carbonaceous particles in the whole period were internally mixed with nitrate and sulfate,implying that most of the carbonaceous particles were associated with secondary oxidation during their formation processes.The diurnal variations of oxalate particles and correlation analyses suggested that oxalate particles before the pandemic were derived from aqueous oxidation driven by RH and liquid water content(LwC),while oxalate particles during the pandemic were originated from O3-dominatedphotochemical oxidation.
基金supported by the Natural Science Foundation of Shan-dong Province(ZR2021QA089)Doctor Foundation of Yantai Uni-versity(No.2220005).
文摘Multifunctional catalysts that exhibit high catalytic performance for the hydrogen evolution reaction(HER),oxygen evolution reaction(OER),and oxygen reduction reaction(ORR)in a single material hold great promise for broad-spectrum applications,including overall water splitting,fuel cells,and metal-air batteries.In this first-principles study,Cu_(3) N is computationally demonstrated as a multifunctional electrocatalyst for the HER,OER,and ORR owing to the unique coordination of N and Cu atoms on the(001)surface.Cu_(3) N exhibits better HER catalytic activity than noble Pt-based catalysts.Furthermore,its OER and ORR catalytic activity is comparable to that of commercialized unifunctional catalysts,and its 4e-pathway selectivity is high during the ORR.The catalytic performance of the ORR is significantly improved by the introduction of vacancy defects.The integration of highly efficient HER,OER,and ORR catalytic performance in earth-abundant Cu_(3) N not only opens an avenue for developing cost-efficient omnipotent catalysts but also facilitates advances in clean and renewable energy.
基金supported by the National Natural Science Foundation of China (21433006 and 11774201)
文摘Two-dimensional(2 D)van der Waals materials have been widely adopted as photocatalysts for water splitting,but the energy conversion efficiency remains low.On the basis of first-principles calculations,we demonstrate that the 2 D Janus group-Ⅲchalcogenide multilayers:In Ga XY,M2XY and In GaX2(M=In/Ga;X,Y=S/Se/Te),are promising photocatalysts for highly-efficient overall water splitting.The intrinsic electric field enhances the spatial separations of photogenerated carriers and alters the band alignment,which is more pronounced compared with the Janus monolayers.High solar-to-hydrogen(STH)efficiency with the upper limit of 38.5%was predicted in the Janus multilayers.More excitingly,the Ga vacancy of In Ga SSe bilayer effectively lowers the overpotentials of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)to the levels provided solely by the photogenerated carriers.Our theoretical results suggest that the 2 D Janus group-III chalcogenide multilayers could be utilized as highly efficient photocatalysts for overall water splitting without the needs of sacrificial reagents.
基金supported by the Basic Research Project of Natural Science Foundation of Shandong Province(ZR2018ZB0751)the National Natural Science Foundation of China(11774201)the Taishan Scholar Program of Shandong Province。
文摘Multifunctional catalysts that integrate high efficiency hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR) catalytic activity in a single material are attractive for unitized regenerative fuel cells and overall water splitting technologies. As the best-known HER and ORR electrocatalysts, Pt and its alloys have only moderate OER activity. Ruthenium and iridium oxides exhibit the highest OER activities but not as active as Pt for HER and ORR. Here, we proposed a general principle for achieving trifunctional electrocatalysis for three reactions in a single material. Using the newly-synthesized pyrazine-modified graphdiyne(PR-GDY) as an example, we demonstrated that the synergistic effect of the pyridinic nitrogen and anchored transition-metal(TM) single atoms renders highly-efficient HER/OER/ORR trifunctional electrocatalytic activity. For the Ni-doped PR-GDY, the overpotentials for HER, OER and ORR can be respectively as low as -0.05, 0.29 and 0.38 V, which are comparable or even superior to the best-known single-functional and bi-functional precious electrocatalysts.These computational results offer not only a promising trifunctional electrocatalyst but also a strategy for the design of multifunctional electrocatalysts.
基金We gratefully acknowledge financial support from the National Natural Science Foundation of China （Nos. 81620108027, 21632008, 21472209, 21672231 and 81220108025）, the Major Project of Chinese National Programs for Fundamental Research and Development （No. 2015CB910304）, National S＆T Major Projects （No. 2014ZX09507002-001）, and the State Key Laboratory of Bioorganic Chemistry.
文摘The asymmetric a-sulfenylation of Ni（II） complex of glycine with S-substituted 4-methylbenzenesulfonothioate is reported. Due to the mild and simple reaction conditions, this asymmetric reaction is compatible with various functional groups.
