Traditional metal sulfides used as anodes for sodium-ion batteries are hindered by sluggish kinetics,which limits their rate performance.Previous attempts to address this issue focused on nanostructured configurations...Traditional metal sulfides used as anodes for sodium-ion batteries are hindered by sluggish kinetics,which limits their rate performance.Previous attempts to address this issue focused on nanostructured configurations with conductive frameworks.However,these nanomaterials often suffer from low packing density and the tendency for nanoparticles to agglomerate,posing significant challenges for practical applications.To overcome these limitations,this study presents a novel bimetal superionic anode material Cu_(3.21)Bi_(4.79)S_(9),which effectively resolves the conflict between sluggish kinetics and micrometer-scale particle size.By leveraging the vacancies created by free Cu and Bi atoms,this material forms rapid migration channels during sodium insertion and extraction,significantly reducing the migration barriers for sodium ions.The development of micrometer-scale Cu_(3.21)Bi_(4.79)S_(9)enables ultrafast chargingdischarging capabilities,achieving a reversible capacity of 325.5 mAh g^(-1)after 4000 cycles at a high rate of 45 C(15 A g^(-1)).This work marks a significant advancement in the field by offering a solution to the inherent trade-off between high capacity and rate performance in coarse-grained materials,reducing the need for reliance on nanostructured configurations for next-generation high-capacity anode materials.展开更多
A novel unsupervised approach to automatically constructing multilevel image clusters from unordered im- ages is proposed in this paper. The whole input image col- lection is represented as an imaging sample space （...A novel unsupervised approach to automatically constructing multilevel image clusters from unordered im- ages is proposed in this paper. The whole input image col- lection is represented as an imaging sample space （ISS） con- sisting of globally indexed image features extracted by a new efficient multi^view image feature matching method. By mak- ing an analogy between image capturing and observation of ISS, each image is represented as a binary sequence, in which each bit indicates the visibility of a corresponding feature. Based on information theory-inspired image popularity and dissimilarity measures, we show that the image content and distance can be quantitatively described, guided by which an input image collection is organized into multilevel clusters automatically. The effectiveness and the efficiency of the pro- posed approach are demonstrated using three real image col- lections and promising results were obtained from both qual- itative and quantitative evaluation.展开更多
Trinucleotide repeat expansions (CAG) lead to increase in glutamine residues and hence increase in glutamine stretch. This leads to number of neurodegenerative diseases. Therefore, the conformation of poly Q of varyin...Trinucleotide repeat expansions (CAG) lead to increase in glutamine residues and hence increase in glutamine stretch. This leads to number of neurodegenerative diseases. Therefore, the conformation of poly Q of varying chain lengths has been investigated by quantum mechanical and molecular dynamics approaches. Glutamine contains amide linkage in the side chain. It is the interaction between side chain amide linkage and the peptide bond of the backbone which dictates the conformational behaviour. Some of the glutamine residues adopt phi psi values corresponding to poly-L-proline type II structure. Not more than three glutamine residues are found to have the same set of values and hence polyglutamine is adopting random coil structure. Carbonyl-carbonyl, CH-O interactions and hydrogen bond formation involving backbone and side chain amide chain linkages are found to contribute to the stability of the adopted structure. In simulation studies due to interaction of water molecules with the amide linkages the values undergo change and this leads to weakening of carbonyl-carbonyl interactions and hydrogen bonds. The conformational behaviour of polyglutamine peptides is shown to be chain length dependent and this may provide some insight regarding the aggregation behaviour of proteins containing poly Q stretch. Possibly this is the first systematic study of the conformational behaviour of polyglutamine peptides.展开更多
The unfolding of bovine serum albumin, lysozyme and ribonuclease A denatured in 6 mol/L GuHCl with their disulfide bridges intact and reduced have been compared by FTIR studies. The peak positions and heights in the d...The unfolding of bovine serum albumin, lysozyme and ribonuclease A denatured in 6 mol/L GuHCl with their disulfide bridges intact and reduced have been compared by FTIR studies. The peak positions and heights in the deconvolved spectra of amide I bands of the above denatured proteins with native disulfide bonds show marked differences whereas those for the denatured proteins without disulfide linkages are closely similar. The above and other evidence suggest that denatured proteins with intact disulfides still have considerable ordered conformation even in 6 mol/L GuHCl.展开更多
基金the financial support of the National Natural Science Foundation of China(Grant No.21975036)the Fundamental Research Funds for the Central Universities(Grant No.3132023503).
文摘Traditional metal sulfides used as anodes for sodium-ion batteries are hindered by sluggish kinetics,which limits their rate performance.Previous attempts to address this issue focused on nanostructured configurations with conductive frameworks.However,these nanomaterials often suffer from low packing density and the tendency for nanoparticles to agglomerate,posing significant challenges for practical applications.To overcome these limitations,this study presents a novel bimetal superionic anode material Cu_(3.21)Bi_(4.79)S_(9),which effectively resolves the conflict between sluggish kinetics and micrometer-scale particle size.By leveraging the vacancies created by free Cu and Bi atoms,this material forms rapid migration channels during sodium insertion and extraction,significantly reducing the migration barriers for sodium ions.The development of micrometer-scale Cu_(3.21)Bi_(4.79)S_(9)enables ultrafast chargingdischarging capabilities,achieving a reversible capacity of 325.5 mAh g^(-1)after 4000 cycles at a high rate of 45 C(15 A g^(-1)).This work marks a significant advancement in the field by offering a solution to the inherent trade-off between high capacity and rate performance in coarse-grained materials,reducing the need for reliance on nanostructured configurations for next-generation high-capacity anode materials.
文摘A novel unsupervised approach to automatically constructing multilevel image clusters from unordered im- ages is proposed in this paper. The whole input image col- lection is represented as an imaging sample space （ISS） con- sisting of globally indexed image features extracted by a new efficient multi^view image feature matching method. By mak- ing an analogy between image capturing and observation of ISS, each image is represented as a binary sequence, in which each bit indicates the visibility of a corresponding feature. Based on information theory-inspired image popularity and dissimilarity measures, we show that the image content and distance can be quantitatively described, guided by which an input image collection is organized into multilevel clusters automatically. The effectiveness and the efficiency of the pro- posed approach are demonstrated using three real image col- lections and promising results were obtained from both qual- itative and quantitative evaluation.
文摘Trinucleotide repeat expansions (CAG) lead to increase in glutamine residues and hence increase in glutamine stretch. This leads to number of neurodegenerative diseases. Therefore, the conformation of poly Q of varying chain lengths has been investigated by quantum mechanical and molecular dynamics approaches. Glutamine contains amide linkage in the side chain. It is the interaction between side chain amide linkage and the peptide bond of the backbone which dictates the conformational behaviour. Some of the glutamine residues adopt phi psi values corresponding to poly-L-proline type II structure. Not more than three glutamine residues are found to have the same set of values and hence polyglutamine is adopting random coil structure. Carbonyl-carbonyl, CH-O interactions and hydrogen bond formation involving backbone and side chain amide chain linkages are found to contribute to the stability of the adopted structure. In simulation studies due to interaction of water molecules with the amide linkages the values undergo change and this leads to weakening of carbonyl-carbonyl interactions and hydrogen bonds. The conformational behaviour of polyglutamine peptides is shown to be chain length dependent and this may provide some insight regarding the aggregation behaviour of proteins containing poly Q stretch. Possibly this is the first systematic study of the conformational behaviour of polyglutamine peptides.
文摘The unfolding of bovine serum albumin, lysozyme and ribonuclease A denatured in 6 mol/L GuHCl with their disulfide bridges intact and reduced have been compared by FTIR studies. The peak positions and heights in the deconvolved spectra of amide I bands of the above denatured proteins with native disulfide bonds show marked differences whereas those for the denatured proteins without disulfide linkages are closely similar. The above and other evidence suggest that denatured proteins with intact disulfides still have considerable ordered conformation even in 6 mol/L GuHCl.
