Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality.Photocatalysis,a process that trans...Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality.Photocatalysis,a process that transforms solar energy into clean fuels through a photocatalyst,represents a felicitous direction toward sustainability.Eco-rich metal-free graphitic carbon nitride(g-C_(3)N_(4))is profiled as an attractive photocatalyst due to its fascinating properties,including excellent chemical and thermal stability,moderate band gap,visible light-active nature,and ease of fabrication.Nonetheless,the shortcomings of g-C_(3)N_(4)include fast charge recombination and limited surface-active sites,which adversely affect photocatalytic reactions.Among the modification strategies,point-to-face contact engineering of 2D g-C_(3)N_(4)with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area,short effective charge-transfer pathways,and quantum confinement effects.This review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g-C_(3)N_(4)in the construction of point-to-face heterojunction interfaces.Notably,0D materials such as metals,metal oxides,metal sulfides,metal selenides,metal phosphides,and nonmetals on g-C_(3)N_(4)with different charge-transfer mechanisms are systematically discussed along with controllable synthesis strategies.The applications of 0D/2D g-C_(3)N_(4)-based photocatalysts are focused on solar-to-energy conversion via the hydrogen evolution reaction,the CO_(2)reduction reaction,and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction pathways.Finally,future perspectives for developing high-efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes,large-scale production,machine learning integration,and multidisciplinary advances for technological breakthroughs.展开更多
It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are： （1） A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-w...It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are： （1） A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-weak base; （2） Under （CH）, every separable space with a σ-point-discrete N_0-weak base has a countable N_0-weak base.展开更多
We analyzed the N_(2)0 content of surface seawater sampled from Prydz Bay,Antarctica,on a cruise track between 30°S and 30°N during the twenty-second Chinese National Antarctic Research Expedition during aus...We analyzed the N_(2)0 content of surface seawater sampled from Prydz Bay,Antarctica,on a cruise track between 30°S and 30°N during the twenty-second Chinese National Antarctic Research Expedition during austral summer,2006.The surface water showed an average pN_(2)0 value of 311.9a:7.6 nL.L-1(14.1:t:0.4 nmol-Ll),which was slightly undersaturated.The air-sea N_(2)O flux in the region was-0.3±0.8 p.mol.mE,dl;howeveh N_(2)0 in the surface water was oversaturated in most stations along the cruise track.Saturation anomalies were greater than 10%,with a maximum of 54.7%being observed at the Eqaator,followed by 31%at 10°N in the Sulu Sea.The air-sea fluxes at these locations were 12.4 and 4μmol-mLd-1,respectively.Overall,the results indicated that surface water in Prydz Bay was near equilibrium with atmospheric N_(2)0,and that ocean waters in lower latitudes acted as a N_(2)0 source.Physical processes such as stratification,ice-melt water dilution,and solar radiation dominate the factors leading to N_(2)0 saturation of surface water of Prydz Bay,while biological production and upwelling are primarily responsible for the N20 oversaturation of surface water observed in subtropical and tropical regions along the cruise track.展开更多
In 1992, Brualdi and Jung first introduced the maximum jump number M(n, k), that is, the maximum number of the jumps of all (0, 1)-matrices of order n with k 1's in each row and column, and then gave a table about...In 1992, Brualdi and Jung first introduced the maximum jump number M(n, k), that is, the maximum number of the jumps of all (0, 1)-matrices of order n with k 1's in each row and column, and then gave a table about the values of M(n, k) when 1 ≤ k ≤ n ≤ 10. They also put forward several conjectures, including the conjecture M(2k - 2, k) = 3k - 4 + [k-2/2]. In this paper, we prove that b(A) ≥ 4 for every A ∈ A(2k - 2, k) if k ≥ 11, and find another counter-example to this conjecture .展开更多
Main observation and conclusion By a strategy of fine-tuning of packing mode between the adjacent layers in a 2D net metal-organic frameworks(MOFs)through ligand changing,two 2D sql-type MOFs with highly selective CO_...Main observation and conclusion By a strategy of fine-tuning of packing mode between the adjacent layers in a 2D net metal-organic frameworks(MOFs)through ligand changing,two 2D sql-type MOFs with highly selective CO_(2)uptake,CuHIN and CuHPB,were successfully synthesized.Compared with the precursor MOF-2,the fine-tuning structure of CuHIN shows selective adsorption of CO_(2)over N_(2)and CH_(4)with the CO_(2)uptake amounts as high as 4.7 wt%at 0.15 bar and at 298 K,and CO_(2)selectivity towards N_(2)and CH_(4)is 165.8 and 10.22 at 1 bar and at 298 K,respectively.In addition,for the 2D MOFs,the dynamic porous structure depends on the interaction of the adjacent layers.The suitable interaction is good for gliding smoothly and gas adsorption.展开更多
基金Ministry of Higher Education,Malaysia,Grant/Award Number:FRGS/1/2020/TK0/XMU/02/1Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2021A1515111019+1 种基金Hengyuan International Sdn.Bhd.,Grant/Award Number:EENG/0003Xiamen University Malaysia,Grant/Award Numbers:IENG/0038,ICOE/0001,XMUMRF/2019-C3/IENG/0013,XMUMRF/2021-C8/IENG/0041。
文摘Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality.Photocatalysis,a process that transforms solar energy into clean fuels through a photocatalyst,represents a felicitous direction toward sustainability.Eco-rich metal-free graphitic carbon nitride(g-C_(3)N_(4))is profiled as an attractive photocatalyst due to its fascinating properties,including excellent chemical and thermal stability,moderate band gap,visible light-active nature,and ease of fabrication.Nonetheless,the shortcomings of g-C_(3)N_(4)include fast charge recombination and limited surface-active sites,which adversely affect photocatalytic reactions.Among the modification strategies,point-to-face contact engineering of 2D g-C_(3)N_(4)with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area,short effective charge-transfer pathways,and quantum confinement effects.This review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g-C_(3)N_(4)in the construction of point-to-face heterojunction interfaces.Notably,0D materials such as metals,metal oxides,metal sulfides,metal selenides,metal phosphides,and nonmetals on g-C_(3)N_(4)with different charge-transfer mechanisms are systematically discussed along with controllable synthesis strategies.The applications of 0D/2D g-C_(3)N_(4)-based photocatalysts are focused on solar-to-energy conversion via the hydrogen evolution reaction,the CO_(2)reduction reaction,and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction pathways.Finally,future perspectives for developing high-efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes,large-scale production,machine learning integration,and multidisciplinary advances for technological breakthroughs.
基金Supported by the National Natural Science Foundation of China (10971185, 11171162, 11201053)China Postdoctoral Science Foundation funded project (20090461093, 201003571)+1 种基金Jiangsu Planned Projects for Teachers Overseas Research FundsTaizhou Teachers College Research Funds
文摘It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are： （1） A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-weak base; （2） Under （CH）, every separable space with a σ-point-discrete N_0-weak base has a countable N_0-weak base.
基金the National Natural Science Foundation of China (Grant nos.40671062,41106168)the National High Technique Research & Development Program of China (Grant no.2008AA121703)+1 种基金the Ministry of Science and Technology of China (Grant nos.2004DIB5J178,2009DFA22920)the Chinese Arctic and Antarctic Admini-stration (CAA) Cooperation Program (Grant nos.IC2010013,IC2011114,IC201201)
文摘We analyzed the N_(2)0 content of surface seawater sampled from Prydz Bay,Antarctica,on a cruise track between 30°S and 30°N during the twenty-second Chinese National Antarctic Research Expedition during austral summer,2006.The surface water showed an average pN_(2)0 value of 311.9a:7.6 nL.L-1(14.1:t:0.4 nmol-Ll),which was slightly undersaturated.The air-sea N_(2)O flux in the region was-0.3±0.8 p.mol.mE,dl;howeveh N_(2)0 in the surface water was oversaturated in most stations along the cruise track.Saturation anomalies were greater than 10%,with a maximum of 54.7%being observed at the Eqaator,followed by 31%at 10°N in the Sulu Sea.The air-sea fluxes at these locations were 12.4 and 4μmol-mLd-1,respectively.Overall,the results indicated that surface water in Prydz Bay was near equilibrium with atmospheric N_(2)0,and that ocean waters in lower latitudes acted as a N_(2)0 source.Physical processes such as stratification,ice-melt water dilution,and solar radiation dominate the factors leading to N_(2)0 saturation of surface water of Prydz Bay,while biological production and upwelling are primarily responsible for the N20 oversaturation of surface water observed in subtropical and tropical regions along the cruise track.
基金Hainan Natural Science Foundation of Hainan (10002)
文摘In 1992, Brualdi and Jung first introduced the maximum jump number M(n, k), that is, the maximum number of the jumps of all (0, 1)-matrices of order n with k 1's in each row and column, and then gave a table about the values of M(n, k) when 1 ≤ k ≤ n ≤ 10. They also put forward several conjectures, including the conjecture M(2k - 2, k) = 3k - 4 + [k-2/2]. In this paper, we prove that b(A) ≥ 4 for every A ∈ A(2k - 2, k) if k ≥ 11, and find another counter-example to this conjecture .
基金supported by the National Natural Science Foundation of China(21890383 and 21901135)the China Postdoctoral Science Foundation(2020M680536)the State Key Laboratory of Coordination Chemistry(SKLCC2106).
文摘Main observation and conclusion By a strategy of fine-tuning of packing mode between the adjacent layers in a 2D net metal-organic frameworks(MOFs)through ligand changing,two 2D sql-type MOFs with highly selective CO_(2)uptake,CuHIN and CuHPB,were successfully synthesized.Compared with the precursor MOF-2,the fine-tuning structure of CuHIN shows selective adsorption of CO_(2)over N_(2)and CH_(4)with the CO_(2)uptake amounts as high as 4.7 wt%at 0.15 bar and at 298 K,and CO_(2)selectivity towards N_(2)and CH_(4)is 165.8 and 10.22 at 1 bar and at 298 K,respectively.In addition,for the 2D MOFs,the dynamic porous structure depends on the interaction of the adjacent layers.The suitable interaction is good for gliding smoothly and gas adsorption.
