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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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    Study on crystal morphology and melting properties of the isothermally crystallized poly(trimethylene terephthalate)

    Mingtao RunYanping HaoHongzan Song
    259-262页
    查看更多>>摘要：The spherulites' morphology and melting properties of the poly(trimethylene terephthalate) formed in limited space at specific temperatures was studied by the polarized optical microscopy (POM). The results suggest that the spherulites' morphology depends strongly on the temperature. When the isothermal crystallization temperatures increase from 190 to 225 ℃, the spherulites' morphology continuously changes in the following order: nonbanded → regular banded → serrated banded → nonbanded spherulites. Furthermore, the band spacing increases with the crystallization temperature. Heating the banded spherulites will cause them melt as well as the changing of the bandings, especially the bandings changes in the following order: clear → faint → clear → disappear in a certain range of temperature, which is proposed for resulting from a lamellar melting-recrystallization-remelting mechanism.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Laser diffractions in lyotropic liquid crystal formed by sodium dodecyl sulfonate

    Wei-wei LiuYuan Ming Huang
    263-266页
    查看更多>>摘要：The laser diffractions phenomenon of surrounding bubbles of lyotropic liquid crystal formed by sodium dodecylsulfonate were investigated with polarized optical microscope and helium-neon laser, respectively. The eleven orders of diffractions can be observed when a beam of helium-neon laser is perpendicularly incident on the surrounding bubbles of lyotropic liquid crystal formed by sodium dodecyl sulfonate. The wavelength of the incident light is 633nm. And we have calculated the periodicity,p, of the grating was 0.211 mm, and the small diffraction angle was 0.1146°. So we have simulated the microstructure of surrounding bubbles in the lyotropic liquid crystal formed by sodium dodecyl sulfonate.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Alignment behaviors on ITO glass and electrical properties of triphenylene compound

    Chunxiu ZhangZhiqun HeJialing PuYu Ning...
    267-271页
    查看更多>>摘要：The alignment of 2, 3, 6, 7, 10, 11-hexapentaloxy triphenylene (HAT5) on ITO glasses was investigated by polarizing optical microscopy, differential scanning calorimeter, X-ray diffraction and scan scanning electron microscope in this study. The results showed that the alignment of 2, 3, 6, 7, 10, 11-hexapentaloxy triphenylene can be fixed at room temperature by heating the sample to the isotropic temperature and annealing at 100℃ overnight and then cooling slowly back to room temperature; the ordered arrangements of the micro structures are disconnected. The disconnection of the microstructure and the size of columnar assemblies can also be confirmed from the SEM observations.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Groove-free optical gratings self-assembled by banana-shaped molecules

    Yuan Ming HuangQing-Ian MaBao-gai Zhai
    272-275页
    查看更多>>摘要：We demonstrate that banana-shaped molecules 1,3-phenylene bis(4-methoxybenzylidene amine) can assemble themselves into diffraction gratings when the melt of the banana-shaped compound, which was sandwiched between two pieces of glass substrates, is cooled to room temperature. Polarizing optical microscopic characterization shows that a pattern of periodic modulation of the refractive index can be developed in the thin films formed by the banana-shaped compound. Despite the gratings are groove free, their optical properties are the same as classically ruled gratings. Our work provides an alternative method for manufacturing diffraction gratings by harnessing the self-assembly of banana-shaped molecules.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Photo-alignment effect in liquid-crystal films containing nanoparticles and azo-dye

    Tsung-Hsien LinWen-Zheng Chen
    276-279页
    查看更多>>摘要：This work reports the photo-alignment effect in a liquid-crystal film doped with nanoparticles and azo-dye. Vertical alignment induced by the nanoparticles polyhedral oligomeric silsesquioxanes (POSS) can be switched to homogeneous alignment by the absorption of photo-excited azo-dye. Both electro-optical and surface properties are analyzed to verify this effect. Using this photo-alignment technique in nanoparticle- and azo-dye-doped liquid crystal, the phase grating is also demonstrated. The diffraction efficiency is related to the polarization of the probe light and can be controlled by applying voltage. Both nanoparticle- and azo-dye-induced vertical and homogeneous alignments are non-contact aligning methods. Thus, the technique based on dopant-induced alignment has potential for practical applications.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    A smart bent-core liquid crystal to write Chinese characters

    Yuan Ming HuangBao-gai ZhaiQing-Ian Ma
    280-283页
    查看更多>>摘要：We demonstrate that a bent-core liquid crystal l,3-phenylene-bis(4-butoxybenzylidene amine) can write the Chinese character A, which means a person in English, when the bent-core compound gets cooled from its isotropic phase. The polarized optical microscopic graphs illustrate that the bent-core molecules are able to self-assemble themselves into the Chinese character either in a sequential order or in a reverse order. Our results reveal that bent-core molecules have the capability of being smart materials.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Alignment change of discotic liquid crystal domains with wavelength tunable CO_2 laser irradiation

    Hirosato MonobeYo Shimizu
    284-287页
    查看更多>>摘要：Infrared-induced alignment change with wavelength tunable CO_2 laser irradiation for columnar liquid crystal domains was investigated for a triphenylene-based discotic liquid crystal. A uniformly aligned alignment change of domains was observed when a plused linearly polarized infrared laser light corresponding to the wavelength of the aromatic C-O-C stretching vibration band (9.65μm) was irradiated while it was not re-aligned uniformly with continious wave irradiation. The results strongly imply that the infrared irradiation is a possible technique for device fabrication by use of columnar mesophase as a liquid crystalline semiconductor.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Blue light emission from a rod-like liquid crystal

    Bao-gai ZhaiYuan Ming Huang
    288-291页
    查看更多>>摘要：A rod-like liquid crystal 4-butoxybenzylidene-4'-octylphenylamine was synthesized. The molecular structure and the liquid crystalline phases of the synthesized compound were characterized with the nuclear magnetic resonance spectroscopy, the differential scanning calorimetry, and the polarizing optical microscopy, respectively. The absorption measurement shows that the dilute tetrahydrofuran solutions of the rod-like liquid crystal absorb photons at about 290 and 330 nm, respectively; while the luminescence measurements indicate that this rod-like liquid crystal can give off intense blue photoluminescence with its dominant peak located at about 430 nm. Using Hueckel tight-binding program, we have calculated the electronic structures of the liquid crystal, and the origin of the blue photoluminescence is discussed.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Liquid crystalline behavior of mixture of two non-mesogenic compounds

    J. MahadevaNagappa
    292-296页
    查看更多>>摘要：The lyotropic liquid crystalline behavior of N-Cetyl-N, N, N, Trimethyl Ammonium Bromide (CTAB) with ethylene glycol (EG) has been investigated. These compounds are non-mesogenic in nature and exhibits Sm A, Sm B and Sm G phases. The stability of the phases is investigated using X-ray diffraction and optical studies. The layer thickness and molecular length are calculated using Bragg's equation. The interfacial area per polar group and average thickness of hydrocarbon layers are estimated for different concentrations of the mixtures at different temperatures.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Optical switching properties of an azo-containing banana-shaped liquid crystal

    Yuan Ming HuangBao-gai Zhai
    297-300页
    查看更多>>摘要：By triangular wave method, the switching currents of an azo-containing banana-shaped antiferroelectric liquid crystal were investigated as a function of temperature. As the temperature increases from 150 to 175℃, the switching currents of the banana-shaped liquid crystal were observed to decrease linearly with the temperature. The unusual temperature-dependent polarization was discussed in the light of Landau-de Gennes theory.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd