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Single-crystal star-like zinc oxide: synthesis, characterization and growth mechanism

Rare Metals 2006年第z2期25卷 193-199页

作者： WANG Qingxiao YOU Liping Zhang Xinzheng WANG Rongming LV Yuzhen GUO Lin School of Physics Beijing University Beijing 100871 China School of Physics Beijing University Beijing 100871 China School of Physics Beijing University Beijing 100871 China School of Science Beijing University of Aeronautics and Astronautics Beijing 100083 China 　 School of Materials Science and Technology Beijing University of Aeronautics and Astronautics Beijing 100083 China

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.

关键词： star-like single-crystal solvothermal method CBED

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H_2/CO_2 Gas Transport Performance in Poly(Ethylene Oxide) Reverse-selective Membrane with star-like Structures

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Journal of Wuhan University of Technology(Materials Science) 2019年第1期34卷 195-200页

作者： ZHAO Hongyong DING Xiaoli State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membrane Tianjin Polytechnic University Tianjin Key Laboratory of Hollow Fiber Membrane Materials and Processes Tianjin Polytechnic University School of Environmental and Chemical Engineering Tianjin Polytechnic University Institute of Separation Material and Process Control School of Material Science and EngineeringTianjin Polytechnic University

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.

关键词： hydrogen purification reverse-selective membrane poly(ethylene oxide) star-like structure

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Synthesis and Characterization of star-like Liquid Crystals Centered by Silicon

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Chinese Chemical Letters 2004年第12期15卷 1423-1426页

作者： JianQiangLIU QiZhenZHANG JingZhiZHANG SchoolofChemistryandChemicalEngineering ShandongUniversityJi＇nan250100 KeyLaboratoryofEducationMinistryonColloid＆InterfaceChemis tryJi＇nan250100

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).

关键词： star-like liquid crystals synthesis phase behavior.

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The accuracy of brackets placement in direct bonding technique: a comparison between the pole-like bracket positioning gauge and the star-like bracket positioning gauge

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Open Journal of Stomatology 2011年第4期1卷 121-125页

作者： Lahcen Ousehal Laila Lazrak Department of Orthodontics Faculty of Dentistry

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.

关键词： Direct Bonding Pole-like Gauge star-like Gauge

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