共查询到20条相似文献,搜索用时 828 毫秒
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本文讨论了平行模压取向成型、垂直模压取向成型、准等静压取向成型的稀土永磁的取向及这三种方法对择优织构的影响。也介绍了采用特殊“保向”措施以达到保持取向后择优织构稳定的良好效果。 相似文献
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利用脉冲激光沉积技术在硅衬底上生长高c轴取向LiNbO3薄膜.研究了衬底温度对薄膜质量的影响,发现衬底温度在600 ℃时获得了具有优异结晶质量的高c轴取向LiNbO3薄膜.采用扫描电镜和透射电镜分别对薄膜的表面、截面进行了分析,结果表明,薄膜表面光滑,晶粒均匀致密,薄膜呈与衬底垂直的柱状结构.棱镜耦合技术制备的LiNbO3薄膜具有优异的光波导性能,光损耗为1.14 dB/cm. 相似文献
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对有承载要求的结构件,强度将直接影响到其使用性能。文中基于正交实验,研究了工艺参数对丁二烯—丙烯腈—苯乙烯三元共聚物(ABS)注塑制件不同方向上拉伸强度的影响。研究结果表明,沿分子取向方向上的强度要高于垂直取向方向上的强度;模具温度对垂直流动方向上拉伸强度的影响显著,强度随模具温度的升高而降低;熔体温度对平行流动方向上拉伸强度影响显著,随熔体温度的升高,强度降低,在垂直流动方向上熔体温度的影响规律相反。 相似文献
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目的研究材料参数以及冲裁工艺对无取向硅钢冲裁回弹的影响规律。方法通过拉伸试验和小孔法分别获得无取向硅钢纵横向力学性能各向异性参数和纵横向残余应力差异,结合理论分析和ABAQUS有限元模拟软件分析材料各向异性、残余应力以及冲裁压边对冲裁回弹的影响规律。结果实际冲裁Φ40 mm的圆片时,垂直轧制方向压边面积明显小于轧制方向压边面积,冲裁圆片轧制方向尺寸大于垂直轧制方向,且直径均大于40 mm。板料垂直轧制方向弹性模量和屈服强度高于轧制方向,轧制方向和垂直轧制方向均为残余压应力,且轧制方向残余压应力明显高于垂直轧制方向。结论无取向硅钢冲裁时,轧制方向回弹大于垂直轧制方向,回弹由材料各向异性、残余应力以及压边面积综合影响导致,且影响程度从大到小依次为:残余应力、各向异性、压边面积。 相似文献
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Pt浓度对磁控溅射制备Co1-xPtx:C薄膜的影响 总被引:1,自引:0,他引:1
采用组合靶,利用磁控共溅射技术制备了Co1-xPtx:C复合纳米颗粒薄膜,研究发现CoPt粒子取向和磁性能与CoPt:C薄膜中的Pt浓度有密切关系,在较高Pt浓度的CoPt:C薄膜中观察到垂直各向异性现象。通过改变Pt浓度,可以获得粒子粒径小于lOnm、矫顽力可控、高的垂直磁晶各向异性能的薄膜。综合考虑,薄膜的最佳成分为Co47Pt53:C,此时矫顽力达到最大。 相似文献
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We have investigated the alignment of a liquid crystal whose orientation is controlled by photoisomerization reaction for use in developing optical devices to improve beam quality. A glass window of a liquid-crystal cell that is coated with poly(vinyl alcohol) doped with azo dye was illuminated with a Hg lamp. We confirmed the dependence of the spatially controlled alignment direction of a liquid crystal on the irradiation time of this ultraviolet light. The new azo dye used in this study substantially reduced the illumination energy density required for aligning liquid-crystal molecules. We have demonstrated the control of polarization and successfully fabricated a serrated apodizing aperture and a soft aperture. 相似文献
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目前,电子信息产品应用广泛,液晶显示器是电子产品的必备元件。低温多晶硅薄膜晶体管液晶显示器(LTPS TFT-LCD)因具有解析度高、响应速度快、能耗低、画质高、性能高等优势而成为继非晶硅之后的新一代有源矩阵液晶显示器。由于LTPS高温制程要求玻璃基板具有较高的应变点和软化点,对玻璃的实际生产提出较大挑战。目前LTPS玻璃基板市场集中度很高,技术基本被国外厂商垄断。因此,开发具有自主知识产权的LTPS玻璃基板具有突破性的意义。 本文详细介绍了LTPS TFT-LCD用玻璃基板的组成、性能及制备方法,指出了玻璃基板制备的工艺难点。归纳了玻璃基板的国内外研究现状,分析了玻璃基板的发展趋势及应用前景,为我国自主研发生产LTPS TFT-LCD用玻璃基板提供参考。 相似文献
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Andreea Irina Barzic Radu Dan Rusu Iuliana Stoica Mariana Dana Damaceanu 《Journal of Materials Science》2014,49(8):3080-3098
Four poly(oxadiazole-imide)s containing naphthalene rings, with different flexibility and molecular weight, are investigated with respect to their rheological properties to establish the optimal processing conditions from solution phase to film state for liquid crystal orientation purposes. The film uniformity and strength are determined by monitoring the flow behavior and chain entanglements. The solution rheological data are in agreement with film tensile testing, revealing that higher molecular weight favors chain entanglements and implicitly the film mechanical resistance. In order to analyze the suitability of these films as alignment layers their surface is patterned by rubbing with two types of velvet. Liquid crystal alignment of 4′-pentyl-4-biphenylcarbonitrile nematic is tested by polarized light microscopy. The resulting behavior is correlated with the polyimide malleability and characteristics of the textile fibers, namely their polarity, size, and mechanical features. The competitive effects between chain flexibility and entanglements, together with the interactions occurring between the polymer and velvet are analyzed in order to explain the surface regularity, which influences the uniformity of the liquid crystal alignment. The contrast between dark and bright states recorded on the liquid crystal cell indicates that some of these polynaphthalimides are promising candidates for liquid crystal display devices. 相似文献
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AbstractIn a multicomponent nematic liquid crystal (NLC) mixture of a liquid crystal (negative-type NLC) and a photosensitive acrylic prepolymer, photopolymerization upon UV irradiation induces the separation of the LC and photosensitive acrylic prepolymer layers, thereby leading to a vertical arrangement of LC molecules. In this study, we propose a simple vertical alignment method for LC molecules, by adding a chiral smectic A (SmA?) liquid crystal having homeotropic texture characteristics to an NLC mixture solution. Measurements of electro-optical properties revealed that the addition of the SmA? LC not only strengthened the anchoring force of the copolymer alignment film surface, but also significantly enhanced the contrast ratio (~73%), response time and grayscale switching performance of the device. 相似文献
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Czung-Yu Ho Fa-Hsin Lin Yu-Tai Tao Jiunn-Yih Lee 《Science and Technology of Advanced Materials》2011,12(6)
In a multicomponent nematic liquid crystal (NLC) mixture of a liquid crystal (negative-type NLC) and a photosensitive acrylic prepolymer, photopolymerization upon UV irradiation induces the separation of the LC and photosensitive acrylic prepolymer layers, thereby leading to a vertical arrangement of LC molecules. In this study, we propose a simple vertical alignment method for LC molecules, by adding a chiral smectic A (SmA∗) liquid crystal having homeotropic texture characteristics to an NLC mixture solution. Measurements of electro-optical properties revealed that the addition of the SmA∗ LC not only strengthened the anchoring force of the copolymer alignment film surface, but also significantly enhanced the contrast ratio (∼73%), response time and grayscale switching performance of the device. 相似文献
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Thin film transistor-liquid crystal displays (TFT-LCDs) have become increasingly attractive and popular as display devices. A machine vision approach is proposed for automatic inspection of microdefects in patterned TFT-LCD surfaces. The proposed method is based on a global image reconstruction scheme using singular value decomposition. A partition procedure that separates the input image into non-overlapping sub-images is used to reduce the computation time of singular value decomposition. Taking the pixel image as a matrix, the singular values on the decomposed diagonal matrix represent different structural details of the TFT-LCD image. The proposed method first selects the dominant singular values that represent the repetitive orthogonal-line texture of the TFT-LCD surface. It then reconstructs the matrix by excluding the dominant singular values. The resulting image can effectively remove the background texture and preserves anomalies distinctly. The experiments have evaluated a variety of TFT-LCD microdefects including pinholes, scratches, particles and fingerprints at different image resolutions. The experimental results reveal that the proposed method is effective and efficient for microdefect inspection of TFT-LCD panels. 相似文献
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This investigation elucidates the pozzolanic behavior of waste glass blended cement (WGBC) paste used in thin film transistor liquid crystal displays (TFT-LCD). X-ray diffraction (XRD) results demonstrate that the TFT-LCD waste glass was entirely non-crystalline. The leaching concentrations of the clay and TFT-LCD waste glass all met the current regulatory thresholds of the Taiwan EPA. The pozzolanic strength activity indices of TFT-LCD waste glass at 28 days and 56 days were 89% and 92%, respectively. Accordingly, this material can be regarded as a good pozzolanic material. The amount of TFT-LCD waste glass that is mixed into WGBC pastes affects the strength of the pastes. The strength of the paste clearly declined as the amount of TFT-LCD waste glass increased. XRD patterns indicated that the major difference was the presence of hydrates of calcium silicate (CSH, 2 theta=32.1 degrees), aluminate and aluminosilicate, which was present in WGBC pastes. Portland cement may have increased the alkalinity of the solution and induced the decomposition of the glass phase network. WGBC pastes that contained 40% TFT-LCD waste glass have markedly lower gel/space ratios and exhibit less degree of hydration than ordinary Portland cement (OPC) pastes. The most satisfactory characteristics of the strength were observed when the mixing ratio of the TFT-LCD waste glass was 10%. 相似文献
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Lachezar Komitov 《Thin solid films》2008,516(9):2639-2644
The solid surface in the conventional liquid crystal displays, being responsible for the liquid crystal alignment in the absence of external fields, is playing only a passive role in the switching of the liquid crystal layer. Recently, we have shown that the anchoring strength and the easy axis, two important parameters characterizing the liquid crystal alignment, can effectively be controlled by light via photo-induced nano-scale changes of the solid surface properties. We have also introduced two novel concepts of commanded anchoring, the electrically commanded surfaces (for mediating switching of the liquid crystal) and the high performance alignment layers (for facilitating the switching of the liquid crystal) realized practically by means of a proper nano-engineering of the alignment layer. Electrically commanded anchoring concepts are strong candidates for implementation in a new generation of advanced liquid crystal displays and devices. 相似文献
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We have succeeded in realizing an inclined homeotropic alignment of liquid crystal (LC) molecules by using photo-aligned films of a polyimide containing azobenzene in the backbone structure. To induce such an LC alignment, a side chain structure was introduced into the backbone structure. The LC pretilt angle, measured from the surface normal, could be controlled up to 1.75° by varying the light exposure in oblique angle irradiation with unpolarized light. Its thermal stability was examined by annealing the LC cell at 100 °C. No change was observed in the pretilt angle even after annealing for 36 h, indicative of its excellent thermal stability. Since photo-alignment has patterning capability, the photo-aligned polyimide film is expected as a promising alignment film for multi-domain vertical alignment mode LC displays. 相似文献
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Thet Naing Oo Tetsuya Iwata Munehiro Kimura Tadashi Akahane 《Science and Technology of Advanced Materials》2013,14(2):149-157
The investigation of the surface alignment of liquid crystal (LC) multilayers evaporated on photoaligned polyimide vertical alignment (PI-VA) film was carried out by means of the novel three-dimensional (3D) surface profiler. We report the first use of the surface profiler to visualize a microscopic image of the monolayer arrangement of LC molecules in contact with the surface of photo-treated PI-VA film. The photoinduced anisotropy of partially UV-exposed PI-VA film can be visualized as a topological image of LC multilayers. It seems that the topology of LC multilayers is indicating the orientational distribution of LC molecules on the treated film. It was found that the periodically photoaligned PI-VA film surface can align an adsorbed LC monolayer and the LC molecular alignment can be extended to the bulk via the epitaxylike LC–LC interaction, i.e. a short-range molecular interaction. With regard to the unexposed PI-VA film surface, noticeable anisotropy in the monolayer alignment was not observed, indicating that the long-range elastic interaction may be responsible for the bulk alignment. The appearance of small droplets in the masked region may be presumably related to the dewetting phenomena. 相似文献