As a new technology, Atomil Force Microscopy （AFM） is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coa...As a new technology, Atomil Force Microscopy （AFM） is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coal surface, and measure some structural parameters. Different metamorphic grades produce different feature of surface microscopic structure of coal. This paper analyzes the surface microscopic structure of different metamorphic grade coal by AFM. The results show that the coal surface microstructure has a trend from rough to smooth with the increasing of metamorphic grade. The low rank coals contain large or medium pores and the high rank coals contain micro pores. The values of surface morphology characteristic parameters （Sq and Sa） nonlinearly decrease with the increasing coal rank. That is, the coal surface becomes smoother during coalification.展开更多
Membranes formed by polysulfonamide(PSA)and phosphotungstic acid(PWA)supported on nano-silica have been prepared.Fourier transform infrared spectra(FTIR)and thermogravimetric analysis(TGA)were used to characterize the...Membranes formed by polysulfonamide(PSA)and phosphotungstic acid(PWA)supported on nano-silica have been prepared.Fourier transform infrared spectra(FTIR)and thermogravimetric analysis(TGA)were used to characterize the structure and thermal properties of obtained membranes.The analyses of water uptake,proton conductivity and mechanical properties of the membranes revealed that PWA and silica produced a beneficial effect on proton conduction of the membranes.The membranes with 50 wt% of PWA-SiO2 /PSA were mechanically stable and gave proton conductivity of 2.57×10-2 S·cm-1 at 90℃ and 100% relative humidity.According to the obtained results,PWA and SiO2 doped PSA is a promising material for proton exchange membrane.展开更多
The main phase transition temperature of a lipid membrane, which is vital for its biomedical applications such as controllable drug release, can be regulated by encapsulating hydrophobic nanoparticles into the membran...The main phase transition temperature of a lipid membrane, which is vital for its biomedical applications such as controllable drug release, can be regulated by encapsulating hydrophobic nanoparticles into the membrane. However, the exact relationship between surface properties of the encapsulating nanoparticles and the main phase transition temperature of a lipid membrane is far from clear. In the present work we performed coarse-grained molecular dynamics simulations to meet this end. The results show the surface roughness of nanoparticles and the density of surface-modifying molecules on the nanoparticles are responsible for the regulation. Increasing the surface roughness of the nanoparticles increases the main phase transition temperature of the lipid membrane, whereas it can be decreased in a nonlinear way via increasing the density of surface-modifying molecules on the nanoparticles. The results may provide insights for understanding recent experimental studies and promote the applications of nanoparticles in controllable drug release by regulating the main phase transition temperature of lipid vesicles.展开更多
Using density functional theory calculations, we have investigated the mechanical properties and strain effects on the electronic structure and transport properties of molybdenum disulfide （MoS2） nanotubes. At a sim...Using density functional theory calculations, we have investigated the mechanical properties and strain effects on the electronic structure and transport properties of molybdenum disulfide （MoS2） nanotubes. At a similar diameter, an armchair nanotube has a higher Young＇s modulus and Poisson ratio than its zigzag counterpart due to the different orientations of Mo-S bond topologies. An increase in axial tensile strain leads to a progressive decrease in the band gap for both armchair and zigzag nanotubes. For armchair nanotube, however, there is a semiconductor-to-metal transition at the tensile strain of about 8%. For both armchair and zigzag nanotubes, the effective mass of a hole is uniformly larger than its electron counterpart, and is more sensitive to strain. Based on deformation potential theory, we have calculated the carrier mobilities of MoS2 nanotubes. It is found that the hole mobility is higher than its electron counterpart for armchair （6, 6） nanotube while the electron mobility is higher than its hole counterpart for zigzag （10, 0） nanotube. Our results highlight the tunable electronic properties of MoS2 nanotubes, promising for interesting applications in nanodevices, such as opto-electronics, photoluminescence, electronic switch and nanoscale strain sensor.展开更多
基金Supported by the National Natural Science Foundation of China （41072153） the “Strategic Priority Research Program-Climate Change： Carbon Budget and Related Issues” of the Chinese Academy of Sciences （XDA05030100） the Foundation for University Key Teacher by Education Department of Henan Province （2009GGJS-038）.
文摘As a new technology, Atomil Force Microscopy （AFM） is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coal surface, and measure some structural parameters. Different metamorphic grades produce different feature of surface microscopic structure of coal. This paper analyzes the surface microscopic structure of different metamorphic grade coal by AFM. The results show that the coal surface microstructure has a trend from rough to smooth with the increasing of metamorphic grade. The low rank coals contain large or medium pores and the high rank coals contain micro pores. The values of surface morphology characteristic parameters （Sq and Sa） nonlinearly decrease with the increasing coal rank. That is, the coal surface becomes smoother during coalification.
文摘Membranes formed by polysulfonamide(PSA)and phosphotungstic acid(PWA)supported on nano-silica have been prepared.Fourier transform infrared spectra(FTIR)and thermogravimetric analysis(TGA)were used to characterize the structure and thermal properties of obtained membranes.The analyses of water uptake,proton conductivity and mechanical properties of the membranes revealed that PWA and silica produced a beneficial effect on proton conduction of the membranes.The membranes with 50 wt% of PWA-SiO2 /PSA were mechanically stable and gave proton conductivity of 2.57×10-2 S·cm-1 at 90℃ and 100% relative humidity.According to the obtained results,PWA and SiO2 doped PSA is a promising material for proton exchange membrane.
文摘The main phase transition temperature of a lipid membrane, which is vital for its biomedical applications such as controllable drug release, can be regulated by encapsulating hydrophobic nanoparticles into the membrane. However, the exact relationship between surface properties of the encapsulating nanoparticles and the main phase transition temperature of a lipid membrane is far from clear. In the present work we performed coarse-grained molecular dynamics simulations to meet this end. The results show the surface roughness of nanoparticles and the density of surface-modifying molecules on the nanoparticles are responsible for the regulation. Increasing the surface roughness of the nanoparticles increases the main phase transition temperature of the lipid membrane, whereas it can be decreased in a nonlinear way via increasing the density of surface-modifying molecules on the nanoparticles. The results may provide insights for understanding recent experimental studies and promote the applications of nanoparticles in controllable drug release by regulating the main phase transition temperature of lipid vesicles.
文摘Using density functional theory calculations, we have investigated the mechanical properties and strain effects on the electronic structure and transport properties of molybdenum disulfide （MoS2） nanotubes. At a similar diameter, an armchair nanotube has a higher Young＇s modulus and Poisson ratio than its zigzag counterpart due to the different orientations of Mo-S bond topologies. An increase in axial tensile strain leads to a progressive decrease in the band gap for both armchair and zigzag nanotubes. For armchair nanotube, however, there is a semiconductor-to-metal transition at the tensile strain of about 8%. For both armchair and zigzag nanotubes, the effective mass of a hole is uniformly larger than its electron counterpart, and is more sensitive to strain. Based on deformation potential theory, we have calculated the carrier mobilities of MoS2 nanotubes. It is found that the hole mobility is higher than its electron counterpart for armchair （6, 6） nanotube while the electron mobility is higher than its hole counterpart for zigzag （10, 0） nanotube. Our results highlight the tunable electronic properties of MoS2 nanotubes, promising for interesting applications in nanodevices, such as opto-electronics, photoluminescence, electronic switch and nanoscale strain sensor.
