Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge....Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.展开更多
2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(...2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.展开更多
Currently,the carbothermal reduction-nitridation(CRN)process is the predominant method for preparing aluminum nitride(AlN)powder.Although AlN powder prepared by CRN process exhibits high purity and excellent sintering...Currently,the carbothermal reduction-nitridation(CRN)process is the predominant method for preparing aluminum nitride(AlN)powder.Although AlN powder prepared by CRN process exhibits high purity and excellent sintering activity,it also presents challenges such as the necessity for high reaction temperatures and difficulties in achieving uniform mixing of its raw materials.This study presents a comprehensive investigation into preparation process of AlN nanopowders using a combination of hydrothermal synthesis and CRN.In the hydrothermal reaction,a homogeneous composite precursor consisting of carbon and boehmite(γ-AlOOH)is synthesized at 200℃using aluminum nitrate as the aluminum source,sucrose as the carbon source,and urea as the precipitant.During the hydrothermal process,the precursor develops a core-shell structure,with boehmite tightly coated with carbon(γ-AlOOH@C)due to electrostatic attraction.Compared with conventional precursor,the hydrothermal hybrid offers many advantages,such as ultrafine particles,uniform particle size distribution,good dispersion,high reactivity,and environmental friendliness.The carbon shell enhances thermodynamic stability of γ-Al_(2)O_(3) compared to the corundum phase(α-Al_(2)O_(3))by preventing the loss of the surface area in alumina.This stability enables γ-Al_(2)O_(3) to maintain high reactivity during CRN process,which initiates at 1300℃,and concludes at 1400℃.The underlying mechanisms are substantiated through experiments and thermodynamic calculations.This research provides a robust theoretical and experimental foundation for the hydrothermal combined carbothermal preparation of non-oxide ceramic nanopowders.展开更多
A strategy for the green synthesis of heterocyclicβ-ketosulfides via nucleophilic substitution ofα-halogenated ketone with het-eroaryl thiols in water media is presented.Compared with the available literature report...A strategy for the green synthesis of heterocyclicβ-ketosulfides via nucleophilic substitution ofα-halogenated ketone with het-eroaryl thiols in water media is presented.Compared with the available literature reports,this new method had the advantages of base-free,additives-free,simple operation,mild condition,greenness,high efficiency,tolerance of a broad scope of substrates.Furth-more,the reaction could easily be scaled up in gram scale and the products also could easily transformed to other useful organic compounds.Mechanism investigation indicated that the tautomerism of pyrimidine-2-thiol to pyrimidine-2(1H)-thione and the hy-drogen bonds played important roles in the reaction.展开更多
Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compa...Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compatibility with industrial processes.Graphene is chemically inert and has a zero-bandgap which poses a problem for its use as a functional layer,and nitrogen doping has become an important way to overcome this.Post-plasma treatment has been explored for the synthesis of nitrogen-doped graphene,but the procedures are intricate and not suitable for large-scale production.We report the direct synthesis of nitrogen-doped graphene on a 4-inch sapphire wafer by ethanol-assisted CVD employing pyridine as the carbon feedstock,where the nitrogen comes from the pyridine and the hydroxyl group in ethanol improves the quality of the graphene produced.Additionally,the types of nitrogen dopant produced and their effects on III-nitride epitaxy were also investigated,resulting in the successful illumination of LED devices.This work presents an effective synthesis strategy for the preparation of nitrogen-doped graphene,and provides a foundation for designing graphene functional layers in optoelectronic devices.展开更多
Energetic materials,characterized by their capacity to store and release substantial energy,hold pivotal significance in some fields,particularly in defense applications.Microfluidics,with its ability to manipulate fl...Energetic materials,characterized by their capacity to store and release substantial energy,hold pivotal significance in some fields,particularly in defense applications.Microfluidics,with its ability to manipulate fluids and facilitate droplet formation at the microscale,enables precise control of chemical reactions.Recent scholarly endeavors have increasingly harnessed microfluidic reactors in the realm of energetic materials,yielding morphologically controllable particles with enhanced uniformity and explosive efficacy.However,crucial insights into microfluidic-based methodologies are dispersed across various publications,necessitating a systematic compilation.Accordingly,this review addresses this gap by concentrating on the synthesis of energetic materials through microfluidics.Specifically,the methods based on micro-mixing and droplets in the previous papers are summarized and the strategies to control the critical parameters within chemical reactions are discussed in detail.Then,the comparison in terms of advantages and disadvantages is attempted.As demonstrated in the last section regarding perspectives,challenges such as clogging,dead zones,and suboptimal production yields are non-ignoble in the promising fields and they might be addressed by integrating sound,optics,or electrical energy to meet heightened requirements.This comprehensive overview aims to consolidate and analyze the diverse array of microfluidic approaches in energetic material synthesis,offering valuable insights for future research directions.展开更多
目的:比较多种运动干预方案对儿童执行功能的影响。方法:检索中国知网、万方、pubmed、Web of science、Embase、Cochrane建库至2022年12月,关于运动干预对儿童执行功能影响的实验研究,采用Cochrane偏倚风险评估工具评估纳入文献质量,根...目的:比较多种运动干预方案对儿童执行功能的影响。方法:检索中国知网、万方、pubmed、Web of science、Embase、Cochrane建库至2022年12月,关于运动干预对儿童执行功能影响的实验研究,采用Cochrane偏倚风险评估工具评估纳入文献质量,根据PICOS原则制定文献的纳入和排除标准,以标准化均数差(SMD)为效应指标。结果:纳入43篇文献(n=5 333)。Meta分析结果显示,促进儿童抑制控制首选单次运动时间≥51min、每周2次、干预周期≥17周的球类运动(SUCRA=86.8);促进儿童工作记忆首选单次运动时间10~30 min、每周2次、干预周期5~8周的球类运动(SUCRA=75.6);促进儿童认知灵活性首选单次运动时间31~50 min、每周2次、干预周期5~8周的球类运动(SUCRA=89.4)。结论:不同运动干预方案对儿童执行功能的影响效应不同。展开更多
基金supported by National Natural Science Foundation of China(52302034,52402060,52202201,52021006)Beijing National Laboratory for Molecular Sciences(BNLMS-CXTD202001)+1 种基金Shenzhen Science and Technology Innovation Commission(KQTD20221101115627004)China Postdoctoral Science Foundation(2024T170972)。
文摘Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.
文摘2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.
基金National Key Research and Development Program of China(2022YFB3708500,2023YFB3611000)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2020ZZ109)。
文摘Currently,the carbothermal reduction-nitridation(CRN)process is the predominant method for preparing aluminum nitride(AlN)powder.Although AlN powder prepared by CRN process exhibits high purity and excellent sintering activity,it also presents challenges such as the necessity for high reaction temperatures and difficulties in achieving uniform mixing of its raw materials.This study presents a comprehensive investigation into preparation process of AlN nanopowders using a combination of hydrothermal synthesis and CRN.In the hydrothermal reaction,a homogeneous composite precursor consisting of carbon and boehmite(γ-AlOOH)is synthesized at 200℃using aluminum nitrate as the aluminum source,sucrose as the carbon source,and urea as the precipitant.During the hydrothermal process,the precursor develops a core-shell structure,with boehmite tightly coated with carbon(γ-AlOOH@C)due to electrostatic attraction.Compared with conventional precursor,the hydrothermal hybrid offers many advantages,such as ultrafine particles,uniform particle size distribution,good dispersion,high reactivity,and environmental friendliness.The carbon shell enhances thermodynamic stability of γ-Al_(2)O_(3) compared to the corundum phase(α-Al_(2)O_(3))by preventing the loss of the surface area in alumina.This stability enables γ-Al_(2)O_(3) to maintain high reactivity during CRN process,which initiates at 1300℃,and concludes at 1400℃.The underlying mechanisms are substantiated through experiments and thermodynamic calculations.This research provides a robust theoretical and experimental foundation for the hydrothermal combined carbothermal preparation of non-oxide ceramic nanopowders.
文摘A strategy for the green synthesis of heterocyclicβ-ketosulfides via nucleophilic substitution ofα-halogenated ketone with het-eroaryl thiols in water media is presented.Compared with the available literature reports,this new method had the advantages of base-free,additives-free,simple operation,mild condition,greenness,high efficiency,tolerance of a broad scope of substrates.Furth-more,the reaction could easily be scaled up in gram scale and the products also could easily transformed to other useful organic compounds.Mechanism investigation indicated that the tautomerism of pyrimidine-2-thiol to pyrimidine-2(1H)-thione and the hy-drogen bonds played important roles in the reaction.
基金National Natural Science Foundation of China(T2188101)。
文摘Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compatibility with industrial processes.Graphene is chemically inert and has a zero-bandgap which poses a problem for its use as a functional layer,and nitrogen doping has become an important way to overcome this.Post-plasma treatment has been explored for the synthesis of nitrogen-doped graphene,but the procedures are intricate and not suitable for large-scale production.We report the direct synthesis of nitrogen-doped graphene on a 4-inch sapphire wafer by ethanol-assisted CVD employing pyridine as the carbon feedstock,where the nitrogen comes from the pyridine and the hydroxyl group in ethanol improves the quality of the graphene produced.Additionally,the types of nitrogen dopant produced and their effects on III-nitride epitaxy were also investigated,resulting in the successful illumination of LED devices.This work presents an effective synthesis strategy for the preparation of nitrogen-doped graphene,and provides a foundation for designing graphene functional layers in optoelectronic devices.
基金financially supported by Science and Technology on Applied Physical Chemistry Laboratory,China(Grant No.61426022220303)supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.52305617)。
文摘Energetic materials,characterized by their capacity to store and release substantial energy,hold pivotal significance in some fields,particularly in defense applications.Microfluidics,with its ability to manipulate fluids and facilitate droplet formation at the microscale,enables precise control of chemical reactions.Recent scholarly endeavors have increasingly harnessed microfluidic reactors in the realm of energetic materials,yielding morphologically controllable particles with enhanced uniformity and explosive efficacy.However,crucial insights into microfluidic-based methodologies are dispersed across various publications,necessitating a systematic compilation.Accordingly,this review addresses this gap by concentrating on the synthesis of energetic materials through microfluidics.Specifically,the methods based on micro-mixing and droplets in the previous papers are summarized and the strategies to control the critical parameters within chemical reactions are discussed in detail.Then,the comparison in terms of advantages and disadvantages is attempted.As demonstrated in the last section regarding perspectives,challenges such as clogging,dead zones,and suboptimal production yields are non-ignoble in the promising fields and they might be addressed by integrating sound,optics,or electrical energy to meet heightened requirements.This comprehensive overview aims to consolidate and analyze the diverse array of microfluidic approaches in energetic material synthesis,offering valuable insights for future research directions.
