Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to compare the composition and morphology of the unmodified and the modified fiber...Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to compare the composition and morphology of the unmodified and the modified fibers. The results show that electromagnetism parameters of the modified are different from those of the unmodified. After modification by nano-Ni, the micro-coiled chiral carbon fibers have decreased permittivity and electrical loss. The permeability and magnetic loss of the modified carbon fibers become larger than those of the unmodified ones. Moreover, the modification of unmodified chiral carbon fibers into the modified is much like changing hollow electric windings into those with magnetic cores inside. The modifier intensifies the cross polarization of the chiral carbon fibers and makes the permittivity and the permeability get closer to each other which improves the matching performance and enhances absorbability of coatings. In the range of 6-18 GHz, the reflectivity of the coating is 6-8dB and the bandwidth is 12 GHz. The area density of the coating is below 3 kg/m^2.展开更多
The molecular orientation of ellipsoidal C70 in carbon nanotubes is carefully studied by first principles calculations. Using (14, 7) single-wall carbon nanotube (SWCNT) as a prototype material, we explored that t...The molecular orientation of ellipsoidal C70 in carbon nanotubes is carefully studied by first principles calculations. Using (14, 7) single-wall carbon nanotube (SWCNT) as a prototype material, we explored that the weak chemical interaction between SWCNT and C70 was the crucial factor to determine the molecular orientation. However, the small energy difference makes the distinguishment of two possible molecular orientations difficult. By simulating scanning tunneling microscope images and optical properties, we found that local electronic states sensitively depended on the molecular orientation of ellipsoidal C70, which provided a practical way of using scanning tunneling microscope to recognize the molecular orientation of ellipsoidal C70.展开更多
Chiral catalysis is one of the most direct and effective approach to obtain pure optical enantiomers.Chiral carbon dots(CDs)as carbon-based chiral catalysts show great potential in chiral catalysis.Herein,we report a ...Chiral catalysis is one of the most direct and effective approach to obtain pure optical enantiomers.Chiral carbon dots(CDs)as carbon-based chiral catalysts show great potential in chiral catalysis.Herein,we report a facile one step base-catalyzed aldol condensation to fabricate the chiral CDs from glucose at ambient temperature and pressure.The formation of chiral CDs involves the processes of isomerization and aldol condensation.These chiral CDs have been demonstrated that they have selective capacity for electrocatalytic oxidization of tryptophan enantiomers.L type of CDs(LCDs)is more likely to catalyze L-tryptophan(Trp)than D-Trp with the selective factor(I_(L)/I_(D))of 1.60,whereas the D type of CDs(DCDs)tends to catalyze D-Trp(I_(L)/I_(D):0.63).Theoretical calculations combined with various contrast experiments(temperature and pH)demonstrate that the selectively electrocatalytic capacity of chiral CDs toward Trp isomers is due to the different hydrogen-bond interactions between chiral CDs and Trp.展开更多
We have studied the axial resistivity of chiral single-walled carbon nanotubes (SWCNTs) in the presence of a combined direct current and high frequency alternating fields. We employed semiclassical Boltzmann equations...We have studied the axial resistivity of chiral single-walled carbon nanotubes (SWCNTs) in the presence of a combined direct current and high frequency alternating fields. We employed semiclassical Boltzmann equations approach and compared our results with a similar study that examined the circumferential resistivity of these unique materials. Our work shows that these materials display similar resistivity for both axial and circumferential directions and this largely depends on temperature, intensities of the applied fields and material parameters such as chiral angle. Based on these low-temperature bidirectional conductivity responses, we propose chiral SWCNTs for design of efficient optoelectronic devices.展开更多
This study is to reveal the effect of interlayer lattice registry on the formation of collapsed double wall carbon nanotubes (DWCNTs). It is found that collapsed carbon nanotubes can be energetically unstable, metasta...This study is to reveal the effect of interlayer lattice registry on the formation of collapsed double wall carbon nanotubes (DWCNTs). It is found that collapsed carbon nanotubes can be energetically unstable, metastable or stable, depending mainly on the diameter of the CNT. A fully collapsed DWCNT can adopt different structural morphologies, such as a straight ribbon, a warping ribbon or a twisted ribbon, depending on the chirality of the CNT, which is similar to single wall carbon nanotubes (SWCNTs). Different from SWCNTs, this study also shows some unique phenomena in the formation of collapsed DWCNTs. A fully collapsed DWCNT can have different combinations of the interlayer lattice registry effect within the inner and outer tube, thus the outer tube can influence the formation of the collapsed CNT via lattice registry effect, sometimes even dominates the twist of the CNT.展开更多
The influence of chirality on the thermal conductivity of single-walled carbon nanotubes (SWNTs) is discussed in this paper, using a non-equilibrium molecular dynamics (NEMD) method. The tube lengths of the SWNTs ...The influence of chirality on the thermal conductivity of single-walled carbon nanotubes (SWNTs) is discussed in this paper, using a non-equilibrium molecular dynamics (NEMD) method. The tube lengths of the SWNTs studied here are 20, 50, and 100 nm, respectively, and at each length the relationship between chiral angle and thermal conductivity of a SWNT is revealed. We find that if the tube length is relatively short, the influence of chirality on the thermal conductivity of a SWNT is more obvious and that a SWNT with a larger chiral angle has a greater thermal conductivity. Moreover, the thermal conductivity of a zigzag SWNT is smaller than that of an armchair one. As the tube length becomes longer, the thermal conductivity increases while the influence of chirality on the thermal conductivity decreases.展开更多
Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC...Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC). Single-walled carbon nanotubes mixed with cellulose trisphenylcarbamate are coated on the silica gel as chiral stationary phases and higher enantioseparation factors are obtained. After a single-walled carbon nanotube is linked to the 6-pesition of cellulose 2,3-bisphenylcarbamate, its enantioseparation resolution increases compared to that of the cellulose trisphenylcarbamate. It is the first time that SWNTs have been applied to enantioseparation. The results indicate that the single-walled carbon nanotubes are good promoters of chiral recognition. This method can be used to improve the enantioseparation efficiency of the polysaccharide chiral stationary phases.展开更多
Using the atomistic-based finite-deformation shell theory, we analytically investigate the coupling between the axial deformation and the torsion in single-wall carbon nanotubes. We find that the axial-strain-induced ...Using the atomistic-based finite-deformation shell theory, we analytically investigate the coupling between the axial deformation and the torsion in single-wall carbon nanotubes. We find that the axial-strain-induced torsion(ASIT) response is limited only to chiral nanotubes. This response is affected by chiralities and radii of carbon nanotubes. Our results are similar to that of molecular dynamic simulations reported in the literatures.展开更多
文摘Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to compare the composition and morphology of the unmodified and the modified fibers. The results show that electromagnetism parameters of the modified are different from those of the unmodified. After modification by nano-Ni, the micro-coiled chiral carbon fibers have decreased permittivity and electrical loss. The permeability and magnetic loss of the modified carbon fibers become larger than those of the unmodified ones. Moreover, the modification of unmodified chiral carbon fibers into the modified is much like changing hollow electric windings into those with magnetic cores inside. The modifier intensifies the cross polarization of the chiral carbon fibers and makes the permittivity and the permeability get closer to each other which improves the matching performance and enhances absorbability of coatings. In the range of 6-18 GHz, the reflectivity of the coating is 6-8dB and the bandwidth is 12 GHz. The area density of the coating is below 3 kg/m^2.
文摘The molecular orientation of ellipsoidal C70 in carbon nanotubes is carefully studied by first principles calculations. Using (14, 7) single-wall carbon nanotube (SWCNT) as a prototype material, we explored that the weak chemical interaction between SWCNT and C70 was the crucial factor to determine the molecular orientation. However, the small energy difference makes the distinguishment of two possible molecular orientations difficult. By simulating scanning tunneling microscope images and optical properties, we found that local electronic states sensitively depended on the molecular orientation of ellipsoidal C70, which provided a practical way of using scanning tunneling microscope to recognize the molecular orientation of ellipsoidal C70.
基金This work is supported by Natural Science Foundation of Jiangsu Province(No.BE2022425)National Key R&D Program of China(Nos.2020YFA0406104 and 2020YFA0406101)+8 种基金National MCF Energy R&D Program of China(No.2018YFE0306105)the National Natural Science Foundation of China(Nos.52271223,52272043,51725204,51972216,52202107,and 52201269)Innovative Research Group Project of the National Natural Science Foundation of China(No.51821002)Key R&D program of Ningxia Hui Autonomous Region(No.2022BEG02006)Ningxia Autonomous Region flexible introduction of science and technology innovation team(No.2021RXTDLX08)Agricultural science and technology innovation project of Suzhou Science and Technology Development Plan(No.SNG2020074)Macao Youths Scholars Program,Collaborative Innovation Center of Suzhou Nano Science and Technologythe 111 ProjectSuzhou Key Laboratory of Functional Nano and Soft Materials.
文摘Chiral catalysis is one of the most direct and effective approach to obtain pure optical enantiomers.Chiral carbon dots(CDs)as carbon-based chiral catalysts show great potential in chiral catalysis.Herein,we report a facile one step base-catalyzed aldol condensation to fabricate the chiral CDs from glucose at ambient temperature and pressure.The formation of chiral CDs involves the processes of isomerization and aldol condensation.These chiral CDs have been demonstrated that they have selective capacity for electrocatalytic oxidization of tryptophan enantiomers.L type of CDs(LCDs)is more likely to catalyze L-tryptophan(Trp)than D-Trp with the selective factor(I_(L)/I_(D))of 1.60,whereas the D type of CDs(DCDs)tends to catalyze D-Trp(I_(L)/I_(D):0.63).Theoretical calculations combined with various contrast experiments(temperature and pH)demonstrate that the selectively electrocatalytic capacity of chiral CDs toward Trp isomers is due to the different hydrogen-bond interactions between chiral CDs and Trp.
文摘We have studied the axial resistivity of chiral single-walled carbon nanotubes (SWCNTs) in the presence of a combined direct current and high frequency alternating fields. We employed semiclassical Boltzmann equations approach and compared our results with a similar study that examined the circumferential resistivity of these unique materials. Our work shows that these materials display similar resistivity for both axial and circumferential directions and this largely depends on temperature, intensities of the applied fields and material parameters such as chiral angle. Based on these low-temperature bidirectional conductivity responses, we propose chiral SWCNTs for design of efficient optoelectronic devices.
基金Project (10542001) supported by the National Natural Science Foundation of China
文摘This study is to reveal the effect of interlayer lattice registry on the formation of collapsed double wall carbon nanotubes (DWCNTs). It is found that collapsed carbon nanotubes can be energetically unstable, metastable or stable, depending mainly on the diameter of the CNT. A fully collapsed DWCNT can adopt different structural morphologies, such as a straight ribbon, a warping ribbon or a twisted ribbon, depending on the chirality of the CNT, which is similar to single wall carbon nanotubes (SWCNTs). Different from SWCNTs, this study also shows some unique phenomena in the formation of collapsed DWCNTs. A fully collapsed DWCNT can have different combinations of the interlayer lattice registry effect within the inner and outer tube, thus the outer tube can influence the formation of the collapsed CNT via lattice registry effect, sometimes even dominates the twist of the CNT.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB933200)the National Natural Science Foundation of China(Grant No.51206167)
文摘The influence of chirality on the thermal conductivity of single-walled carbon nanotubes (SWNTs) is discussed in this paper, using a non-equilibrium molecular dynamics (NEMD) method. The tube lengths of the SWNTs studied here are 20, 50, and 100 nm, respectively, and at each length the relationship between chiral angle and thermal conductivity of a SWNT is revealed. We find that if the tube length is relatively short, the influence of chirality on the thermal conductivity of a SWNT is more obvious and that a SWNT with a larger chiral angle has a greater thermal conductivity. Moreover, the thermal conductivity of a zigzag SWNT is smaller than that of an armchair one. As the tube length becomes longer, the thermal conductivity increases while the influence of chirality on the thermal conductivity decreases.
基金Supported by the National Natural Science Foundation of China(No.30160092)the Natural Science Foundation of Yunnan Province,China(No.2005E0006Z).
文摘Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC). Single-walled carbon nanotubes mixed with cellulose trisphenylcarbamate are coated on the silica gel as chiral stationary phases and higher enantioseparation factors are obtained. After a single-walled carbon nanotube is linked to the 6-pesition of cellulose 2,3-bisphenylcarbamate, its enantioseparation resolution increases compared to that of the cellulose trisphenylcarbamate. It is the first time that SWNTs have been applied to enantioseparation. The results indicate that the single-walled carbon nanotubes are good promoters of chiral recognition. This method can be used to improve the enantioseparation efficiency of the polysaccharide chiral stationary phases.
基金supported by the National Natural Science Foundation of China(No.10772089).
文摘Using the atomistic-based finite-deformation shell theory, we analytically investigate the coupling between the axial deformation and the torsion in single-wall carbon nanotubes. We find that the axial-strain-induced torsion(ASIT) response is limited only to chiral nanotubes. This response is affected by chiralities and radii of carbon nanotubes. Our results are similar to that of molecular dynamic simulations reported in the literatures.