A novel star-like single-crystal ZnO structure was synthesized by a simple solvothermal method. The as-prepared products were characterized by XRD, SEM and TEM. The star-like ZnO, which shows sixfold symmetry, was con...A novel star-like single-crystal ZnO structure was synthesized by a simple solvothermal method. The as-prepared products were characterized by XRD, SEM and TEM. The star-like ZnO, which shows sixfold symmetry, was constructed by six uniform arms distributing symmetrically around the [0001] zone axis. It is also found that the arms are not perpendicular to the [0001] zone axis and each arm is grown at a certain angle with the [0001] direction. CBED pattern and corresponding simulation demonstrate that the convex part of the star-like ZnO is O-terminated (000-1) plane and the concave part is Zn-terminated (0001) plane. H2S plays a crucial role in the synthesis process. The anisotropic growth habit along [0001] and [000-1] results in the formation of star-like structure.展开更多
The synthesis and characterization of two new star-like liquid crystals are reported.They are made of a silicon core and four alkoxyazobenzene monomers in the periphery. Theirphase behaviors and the structures are det...The synthesis and characterization of two new star-like liquid crystals are reported.They are made of a silicon core and four alkoxyazobenzene monomers in the periphery. Theirphase behaviors and the structures are determined by infrared absorption spectroscopy (IR),nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing opticalmicroscope (POM) and differential scanning calorimetry (DSC).展开更多
A series of poly(ethylene oxide)(PEO) membranes with star-like structures for CO_2/H_2 separation were prepared by the photo-polymerization method. The structure of PEO membrane was characterized by Fourier transform ...A series of poly(ethylene oxide)(PEO) membranes with star-like structures for CO_2/H_2 separation were prepared by the photo-polymerization method. The structure of PEO membrane was characterized by Fourier transform infrared spectroscopy(FTIR). The thermal property and inter-segmental distance of polymer chain were investigated by differential scanning calorimetry and wide-angle X-ray diffraction, respectively. The density was determined by hydrostatic weighing method. The gas permeability, solubility and diffusivity of CO_2 and H_2 were investigated in the star-like PEO membranes. The relationship between gas permeation performances and physical properties was also discussed. The membrane exhibits outstanding CO_2 permeability(about 9.7×10^(-11) cm^3(STP) cm/cm^2/s/Pa) and CO_2/H_2 selectivity(about 11) compared with other membranes.展开更多
The accuracy of brackets placement is a key factor in successful orthodontic therapy. An in vitro study was conducted in ten models from a natural maxillary teeth model in order to compare the accuracy of brac- kets p...The accuracy of brackets placement is a key factor in successful orthodontic therapy. An in vitro study was conducted in ten models from a natural maxillary teeth model in order to compare the accuracy of brac- kets placement between two direct bonding instru- ments: the Pole-like Bracket Positioning Gauge and the Star-like Bracket Positioning Gauge. Our results have shown that: The Star-like Bracket Positioning Gauge is more precise in placing brackets vertically, whereas the Pole-like Bracket Positioning Gauge al-lows a better angulation of the bracket. Considering each tooth separately, there is no statistically signifi-cant difference between the two positioning gauges, except that the Star-like gauge gives better results in bracket’s height for the second premolar and the ca-nine, whereas the Pole-like gauge allows for a better positioning and a better vertical angulation of the brackets for the lateral incisor. No statistically signi- ficant difference was found between the two gauges on the mesiodistal position. Overall, the Star-like gau- ge showed a better accuracy in positioning brackets.展开更多
文摘A novel star-like single-crystal ZnO structure was synthesized by a simple solvothermal method. The as-prepared products were characterized by XRD, SEM and TEM. The star-like ZnO, which shows sixfold symmetry, was constructed by six uniform arms distributing symmetrically around the [0001] zone axis. It is also found that the arms are not perpendicular to the [0001] zone axis and each arm is grown at a certain angle with the [0001] direction. CBED pattern and corresponding simulation demonstrate that the convex part of the star-like ZnO is O-terminated (000-1) plane and the concave part is Zn-terminated (0001) plane. H2S plays a crucial role in the synthesis process. The anisotropic growth habit along [0001] and [000-1] results in the formation of star-like structure.
文摘The synthesis and characterization of two new star-like liquid crystals are reported.They are made of a silicon core and four alkoxyazobenzene monomers in the periphery. Theirphase behaviors and the structures are determined by infrared absorption spectroscopy (IR),nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing opticalmicroscope (POM) and differential scanning calorimetry (DSC).
基金Funded by the National Natural Science Foundation of China(Nos.21776217,21506160)the Science and Technology Plans of Tianjin(Nos.17PTSYJC00050,18PTSYJC 00190)
文摘A series of poly(ethylene oxide)(PEO) membranes with star-like structures for CO_2/H_2 separation were prepared by the photo-polymerization method. The structure of PEO membrane was characterized by Fourier transform infrared spectroscopy(FTIR). The thermal property and inter-segmental distance of polymer chain were investigated by differential scanning calorimetry and wide-angle X-ray diffraction, respectively. The density was determined by hydrostatic weighing method. The gas permeability, solubility and diffusivity of CO_2 and H_2 were investigated in the star-like PEO membranes. The relationship between gas permeation performances and physical properties was also discussed. The membrane exhibits outstanding CO_2 permeability(about 9.7×10^(-11) cm^3(STP) cm/cm^2/s/Pa) and CO_2/H_2 selectivity(about 11) compared with other membranes.
文摘The accuracy of brackets placement is a key factor in successful orthodontic therapy. An in vitro study was conducted in ten models from a natural maxillary teeth model in order to compare the accuracy of brac- kets placement between two direct bonding instru- ments: the Pole-like Bracket Positioning Gauge and the Star-like Bracket Positioning Gauge. Our results have shown that: The Star-like Bracket Positioning Gauge is more precise in placing brackets vertically, whereas the Pole-like Bracket Positioning Gauge al-lows a better angulation of the bracket. Considering each tooth separately, there is no statistically signifi-cant difference between the two positioning gauges, except that the Star-like gauge gives better results in bracket’s height for the second premolar and the ca-nine, whereas the Pole-like gauge allows for a better positioning and a better vertical angulation of the brackets for the lateral incisor. No statistically signi- ficant difference was found between the two gauges on the mesiodistal position. Overall, the Star-like gau- ge showed a better accuracy in positioning brackets.
基金Supported by National Nature Science Foundation of China(No.60477003)Science and Technology Committee of Shanghai(No.0552nm006,No.0652nm033)+3 种基金Project of Key Laboratory of Advanced Display and System Applications(Shanghai University) Ministry of Education,China(No.P200503)Shanghai Pujiang Program(No.05PJ14320)Key Project of Photonic Technology(No.06DZ11404)Development Program of High Technology and Innovation of Shanghai Economic Committee Key Project of Expro Panel(No.05dz05803)
