Porous carbon has been applied for lithium-sulfur battery cathodes,and carbonized metal-organic framework(MOF)is advantageous in tuning the morphology.Herein,we have systematically synthesized water-distorted MOF(WDM)...Porous carbon has been applied for lithium-sulfur battery cathodes,and carbonized metal-organic framework(MOF)is advantageous in tuning the morphology.Herein,we have systematically synthesized water-distorted MOF(WDM)derived porous carbon via controlling the proportion of both water in a mixed solvent(dimethylformamide and water)and ligand in MOF-5 precursors(metal and ligand),which is categorized by its morphology(i.e.Cracked stone(closed),Tassel(open)and Intermediate(semi-open)).For example,decrease in water and increase in ligand content induce Cracked stone WDMs which showed the highest specific surface area(2742-2990 m^(2)/g)and pore volume(2.81-3.28 cm^(3)/g)after carbonization.Morphological effect of carbonized WDMs(CWDMs)on battery performance was examined by introducing electrolytes with different sulfur reduction mechanisms(i.e.DOL/DME and ACN_(2) LiTFSITTE):Closed framework effectively confines polysulfide,whereas open framework enhances electrolyte accessibility.The initial capacities of the batteries were in the following order:Cracked stone>Intermediate>Tassel for DOL/DME and Intermediate>Tassel>Cracked stone for ACN_(2) LiTFSI-TTE.To note,Intermediate CWDM exhibited the highest initial capacity and retained capacity after 100 cycles(1398 and 747 mAh/g)in ACN_(2) LiTFSI-TTE electrolyte having advantages from both open and closed frameworks.In sum,we could correlate cathode morphology(openness and pore structure)and electrolyte type(i.e.polysulfide solubility)with lithium-sulfur battery performance.展开更多
Recently,MXenes have attracted considerable attention owing to their unique physical and chemical properties.Construction of MXenes to three-dimensional(3D)porous aerogel structures can play a critical role in realizi...Recently,MXenes have attracted considerable attention owing to their unique physical and chemical properties.Construction of MXenes to three-dimensional(3D)porous aerogel structures can play a critical role in realizing the profound implications of MXenes,especially for environmental remediation.Nevertheless,developing mechanically robust MXene-based aerogels with reversible compressibility under harsh conditions,such as liquid environments,remains challenging due to the insufficient interfacial strength between MXene nanosheets.Herein,3D porous MXene-based nanocomposite aerogels are developed by dual physical and chemical crosslinking strategy with poly(vinyl alcohol)and formaldehyde in this study.The developed MXenebased nanocomposite aerogels with designed interfacial engineering exhibit outstanding structural stability and extremely high reversible compressibility up to 98%strain as well as unprecedented mechanical durability(2000 cycles at 50%strain)in water environment.Moreover,the aerogels show adaptable compressibility when exposed to different solvents,which is explained with the Hansen solubility parameter.Thanks to their high compressibility in water,the robust MXene-based aerogels exhibit excellent methylene blue adsorption performance(adsorption capacity of 117.87 mg·g^(−1))and superior recycling efficiency(89.48%at the 3rd cycle).The porous MXene-based nanocomposite aerogels are also demonstrated with outstanding thermal insulation capability.Therefore,by synergistically taking their porous structure and super elasticity in liquid environment,the MXene-based aerogels show great promise in diverse applications including adsorption and separation,wastewater purification desalination,and thermal management.展开更多
Most plants are polyploid due to whole-genome duplications （WGD） and can thus have duplicated genes. Following a WGD, paralogs are often fractionated （lost） and few duplicate pairs remain. Little attention has bee...Most plants are polyploid due to whole-genome duplications （WGD） and can thus have duplicated genes. Following a WGD, paralogs are often fractionated （lost） and few duplicate pairs remain. Little attention has been paid to the role of DNA methylation in the functional divergence of paralogous genes. Using high- resolution methylation maps of accessions of domesticated and wild soybean, we show that in soybean, a recent paleopolyploid with many paralogs, DNA methylation likely contributed to the elimination of ge- netic redundancy of polyploidy-derived gene paralogs. Transcriptionally silenced paralogs exhibit partic- ular genomic features as they are often associated with proximal transposable elements （TEs） and are pref- erentially located in pericentromeres, likely due to gene movement during evolution. Additionally, we provide evidence that gene methylation associated with proximal TEs is implicated in the divergence of expression profiles between orthologous genes of wild and domesticated soybean, and within populations.展开更多
基金supported by the Basic Science Research Program through the National Research Foundation of Korea by the Korea government(MEST)(grant number NRF2019R1A2C4069922)the“LG Research Fund for New Faculty”by LG Chem。
文摘Porous carbon has been applied for lithium-sulfur battery cathodes,and carbonized metal-organic framework(MOF)is advantageous in tuning the morphology.Herein,we have systematically synthesized water-distorted MOF(WDM)derived porous carbon via controlling the proportion of both water in a mixed solvent(dimethylformamide and water)and ligand in MOF-5 precursors(metal and ligand),which is categorized by its morphology(i.e.Cracked stone(closed),Tassel(open)and Intermediate(semi-open)).For example,decrease in water and increase in ligand content induce Cracked stone WDMs which showed the highest specific surface area(2742-2990 m^(2)/g)and pore volume(2.81-3.28 cm^(3)/g)after carbonization.Morphological effect of carbonized WDMs(CWDMs)on battery performance was examined by introducing electrolytes with different sulfur reduction mechanisms(i.e.DOL/DME and ACN_(2) LiTFSITTE):Closed framework effectively confines polysulfide,whereas open framework enhances electrolyte accessibility.The initial capacities of the batteries were in the following order:Cracked stone>Intermediate>Tassel for DOL/DME and Intermediate>Tassel>Cracked stone for ACN_(2) LiTFSI-TTE.To note,Intermediate CWDM exhibited the highest initial capacity and retained capacity after 100 cycles(1398 and 747 mAh/g)in ACN_(2) LiTFSI-TTE electrolyte having advantages from both open and closed frameworks.In sum,we could correlate cathode morphology(openness and pore structure)and electrolyte type(i.e.polysulfide solubility)with lithium-sulfur battery performance.
基金the National Research Foundation of Korea(No.2022R1A2C3011968).
文摘Recently,MXenes have attracted considerable attention owing to their unique physical and chemical properties.Construction of MXenes to three-dimensional(3D)porous aerogel structures can play a critical role in realizing the profound implications of MXenes,especially for environmental remediation.Nevertheless,developing mechanically robust MXene-based aerogels with reversible compressibility under harsh conditions,such as liquid environments,remains challenging due to the insufficient interfacial strength between MXene nanosheets.Herein,3D porous MXene-based nanocomposite aerogels are developed by dual physical and chemical crosslinking strategy with poly(vinyl alcohol)and formaldehyde in this study.The developed MXenebased nanocomposite aerogels with designed interfacial engineering exhibit outstanding structural stability and extremely high reversible compressibility up to 98%strain as well as unprecedented mechanical durability(2000 cycles at 50%strain)in water environment.Moreover,the aerogels show adaptable compressibility when exposed to different solvents,which is explained with the Hansen solubility parameter.Thanks to their high compressibility in water,the robust MXene-based aerogels exhibit excellent methylene blue adsorption performance(adsorption capacity of 117.87 mg·g^(−1))and superior recycling efficiency(89.48%at the 3rd cycle).The porous MXene-based nanocomposite aerogels are also demonstrated with outstanding thermal insulation capability.Therefore,by synergistically taking their porous structure and super elasticity in liquid environment,the MXene-based aerogels show great promise in diverse applications including adsorption and separation,wastewater purification desalination,and thermal management.
文摘Most plants are polyploid due to whole-genome duplications （WGD） and can thus have duplicated genes. Following a WGD, paralogs are often fractionated （lost） and few duplicate pairs remain. Little attention has been paid to the role of DNA methylation in the functional divergence of paralogous genes. Using high- resolution methylation maps of accessions of domesticated and wild soybean, we show that in soybean, a recent paleopolyploid with many paralogs, DNA methylation likely contributed to the elimination of ge- netic redundancy of polyploidy-derived gene paralogs. Transcriptionally silenced paralogs exhibit partic- ular genomic features as they are often associated with proximal transposable elements （TEs） and are pref- erentially located in pericentromeres, likely due to gene movement during evolution. Additionally, we provide evidence that gene methylation associated with proximal TEs is implicated in the divergence of expression profiles between orthologous genes of wild and domesticated soybean, and within populations.
