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Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
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    Synthesis and mesomorphism of 1,1'-disubstitued ferrocene liquid crystals with a schiff's base bridge

    Qing YanPing HuWen-Hao YuBi-Qin Wang...
    162-166页
    查看更多>>摘要：To investigate the influence of alkyl chain on thermotropic and mesomorphic properties of 1,1'-disubstitued ferrocene derivatives, two series of ferrocene derivatives containing Schiffs base, 1,1'-C_8H_(17)FcC_6H_4COOC_6H_4CH=NC_6H_4OOCC_6H_4R_1 (R_1 = H, OC_nH_(2n+1), n = 2, 4, 6, 8 ) and 1,1'-C_8H_(17)FcC_6H_4COOC_6H_4CH=NC_6H_4N=NC_6H_4R_2(R_2= Br, C1, CH_3 ) have been synthesized and characterized by IR and ~1H NMR. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results showed that all compounds exhibit nematic mesophase. The results show that the flexible alkyl chain connecting with ferrocene moiety could lower the melting points and clearing points, favor the formation of nematic mesophase.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Synthesis and mesomorphic properties of three-ring containing bent-core liquid crystal 1,3-phenylene-bis(4-butoxybenzylideneamine)

    Yuan Ming Huang
    167-170页
    查看更多>>摘要：A three-ring containing bent-core compound l,3-pnenylene-bis(4-butoxybenzylidene amine) was synthesized and characterized with differential scanning calorimetry and polarized optical microscopy. It exhibited mesophases in the temperature range of 48-54℃ for the first cyclic heating and cooling. Our results demonstrated that three-ring containing bent-core molecules can form mesophases.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Electric-field effects in dilute suspensions of carbon nanotubes dispersed in nematic liquid crystals

    Muklesur RahmanWei Lee
    173-181页
    查看更多>>摘要：Colloids composed of liquid-crystal hydrosols exhibit a rich set of interesting phenomena. The coupling between liquid-crystalline media and colloidal particles plays an essential role leading to an abundant source of new physics. In the last few years, peculiar behaviors of carbon-nanotube-doped calamitic liquid crystals have attracted considerable attention. This paper provides a brief introduction to this alluring subject for its on-going research development in this laboratory. First presented are our current understandings of the nematic colloidal system comprising carbon nanotubes and of their possible orientation and dynamics under the application of an external field. Various electro-optical and electrical properties of a liquid-crystal display rectified by the nanoscale carbonaceous guest are then addressed to a larger extent. Dielectric relaxation obtained from a nematic impregnated with carbon nanotubes is also discussed. With historical significance for the dawn of the liquid-crystal-carbon-nanotube research, several important findings of enhanced nonlinear optical properties in typical nematic mesomaterials consisting of suspended nanotubes are delineated. With the new colloidal systems of elongated nanoscale solids dispersed in anisotropic fluids in the mesophase, many new intriguing phenomena are awaiting theoretical and experimental explorations. Collaborations are called to draw attention of interested theoretical physicists, in particular.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Purple photoluminescence from banana-shaped molecules 1,3-phenylene bis(4-methoxybenzylideneamine)

    Yuan Ming HuangBao-gai Zhai
    182-185页
    查看更多>>摘要：The optical absorption and photoluminescence spectra of banana-shaped molecules 1,3-pnenylene bis(4-methoxybenzylideneamine) have been investigated with an ultraviolet-visible spectrometers and a spectrofluorometer, respectively. The optical characterizations indicate that the banana-shaped molecules exhibit strong absorptions in a broad range of 260-370 nm and that they can give off strong purple photoluminescence when excited by ultraviolet photons. Using Huckel tight-binding program, we have calculated the electronic structures of the banana-shaped molecules. In light of the calculated electronic structures, the origin of the purple photoluminescence is discussed, and our results have demonstrated that not only the lowest unoccupied molecular orbital and the highest occupied molecular orbital but also the localized energy levels of the lone pairs are responsible for the recorded purple photoluminescence.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Effect of temperature on the columnar tilt of discotic liquid crystals

    Wenjun ZhengCheng-Yan ChiangChi Wi Ong
    186-193页
    查看更多>>摘要：The effect of temperature on the tilt of discotic columns in a columnar phase has been studied. The homogenous alignment of discotic columns is achieved by applying a mechanical shearing. In the columnar phase, the tilt of the discotic columns at substrate surface is found to change with temperature. A decrease in the temperature of the substrates causes an increase in the pretilt of the discotic columns. The phenomenon is explained based on the consideration of surface free energy at the interface of the substrate.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Photostability of an antiferroelectric banana-shaped liquid crystal

    Lan-li ChenBao-gai ZhaiYuan Ming Huang
    194-197页
    查看更多>>摘要：We have investigated the photostability of an antiferroelectric banana-shaped liquid crystal 4-chloro-1,3-phenylene bis [4-(4-n-tetradecyl) phenylimino methyl] benzoate by measuring its polarization as a function of photo-irradiation duration. Upon intense photo-irradiation for three hours, the banana-shaped liquid crystal exhibits a significant photostability although it bears the linkages of -COO- and -CH=N-.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Dispersion properties of nonlinear bulk polaritons in uniaxial antiferromagnetic film

    Jing BaiShufang FuXuanzhang Wang
    198-201页
    查看更多>>摘要：Nonlinear bulk polaritons in uniaxial antiferromagnetic film are investigated under a magnetic field that is along the anisotropy axial. The numerical calculations show that the nonlinear shift in frequency is very obvious. The antiferromagnetic film presents the strong anisotropy under the magnetic field.
      原文链接:
    • NETL
    • NSTL

    Photochemistry in an azo-containing banana-shaped liquid crystal

    Bao-gai ZhaiLan-li ChenYuan Ming Huang
    202-205页
    查看更多>>摘要：By triangular wave method, the polarization currents of an azo-containing banana-shaped antiferroelectric liquid crystal were investigated as a function of the time of 365-nm ultraviolet irradiation. Under the 365-nm irradiation, the polarization currents were observed to evolve with the time of ultraviolet irradiation until they diminished. The roles of photoisomerization, photolysis and thermolysis were discussed for the azo-containing banana-shaped liquid crystal.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Bistable technology in flat panel display: principle and progress

    Ziqiang Huang
    206-211页
    查看更多>>摘要：Active matrices often related with high grade display devices, due to application of the storage elements, typically thin film transistor (TFT). Because of the complex procedures in the manufacturing TFT, investment of the high value manufacturing equipments and clarification plants is necessary, hence increasing the manufacturing cost of the flat panel, and more importantly, causing the pollution of water and air. As the contribution of TFT array merely exists in supplying storage function for the pixels of the display panel, large efforts have been made to find suitable cells that have bistable effect, so as to substitute the effect of TFT. As the bistable cell is just the storage pixel, one could construct a bistable cell to skip the needs of TFT active matrices. The paper is to introduce currently available bistable display devices in the following field: liquid crystal bistable displays with cholesteric liquid crystals, which is an example to introduce the bistable technology; iMod display devices based on mechanic induced bistable and light interference, which shows the possibility to construct bistable display; and the display based on solid powder movement in air or in vacuum, so called liquid powder displays, which shows how to improve the existed display.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Optical absorption and light emission of a banana-shaped liquid crystal

    Yuan Ming HuangBao-gai Zhai
    212-215页
    查看更多>>摘要：With the ultraviolet-visible spectrometer and photospectrometer, we have investigated the optical absorption and light emission from the dilute tetrahydrofuran solutions of a classical banana-shaped liquid crystal l,3-phenylene-bis[4-(4'-nonyloxy)phenyliminomethyl]benzoate. In the dilute tetrahydrofuran solutions, three optical absorption bands were recorded for the banana-shaped compound at about 255, 290 and 355 nm, respectively. Upon the 325 nm excitation, white light emissions were recorded for the solid phase of the banana-shaped liquid crystal whereas blue-greenish emissions were observed for the banana-shaped molecules in dilute solution.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd