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61.
An in situ self-assembled molecular layer of 1-pyrenesulfonic acid sodium salt as an alignment agent was formed on indium tin oxide substrates for vertically aligning liquid crystals (LCs). The thus-aligned LCs exhibited uniform vertical alignment under crossed polarisers. The electro-optical characteristic of the LC cell fabricated using this method exhibited better performance than those of conventional LC cells with a polyimide alignment layer. Because the proposed alignment method is a simple one and involves low concentrations of the alignment agent (0.05 wt%), it is highly cost-effective. Further, the pyrene derivative, when mixed with LCs, exhibited photoluminescence (PL) under ultraviolet light. Given that the proposed method resulted in highly vertically aligned LCs and the alignment agent exhibited PL, the method should find wide use in the fabrication of colour-filter-free LC displays. 相似文献
62.
We propose a method for fast switching of vertically aligned (VA) negative liquid crystals (LCs) by hiding the relaxation process of LCs. During the turn-off process, a strong in-plane electric field is applied for a short duration of time instead of relying solely on the slow relaxation of LCs. The LC molecules are rotated to the transmission axis of one of the polarisers by the applied in-plane electric field, resulting in turn-off switching that is 5.8 times faster than that of a conventional VA cell. By applying an overdriving scheme, we experimentally obtained a total response time of 3.3 ms. 相似文献
63.
Accurate numerical methods for the propagation of light in large 3D samples with strong lateral variation of the director field require prohibitive amounts of time. We consider and compare a standard spectral method and the Finite Difference in Frequency Domain method, showing that the CPU time can be reduced by one or two orders of magnitude using a perturbation approach or a recently developed Reduced Order Method. The equations obtained are applied to liquid crystal cells with in-plane switching, illuminated by a large incoherent source. The developed formalism, based on numerically exact equations, is particularly suitable for treating magnetic or optically active media and for extending to such media the well known approximations based on the 4 × 4 (Berreman) or 2 × 2 (Jones) matrices. 相似文献
64.
P. Glaister 《International Journal of Mathematical Education in Science & Technology》2013,44(1):110-117
Three techniques for determining a straight line fit to data are compared. The methods are applied to a range of datasets containing one or more outliers, and to a specific example from the field of chemistry. For the method which is the most resistant to the presence of outliers, a Microsoft Excel spreadsheet, as well as two Matlab routines, are included which can be used to determine the slope and intercept estimates. 相似文献
65.
Ronald L. Persky 《International Journal of Mathematical Education in Science & Technology》2013,44(6):927-928
In 1968, Leon Gerber compared (1 + x) a to its kth partial sum as a binomial series. His result is stated and, as an application of this result, a proof of the arithmetic mean–geometric mean inequality is presented. 相似文献
66.
In this paper,we study the surface instability of a cylindrical pore in the absence of stress. This instability is called the Rayleigh-Plateau instabilty. We consider the model developed by Spencer et ... 相似文献
67.
Seung Hyun Sung William B. Farnham Heidi E. Burch Yefim Brun Kai Qi Thomas H. Epps 《Journal of Polymer Science.Polymer Physics》2019,57(24):1663-1672
We demonstrate the directional alignment of perpendicular‐lamellae domains in fluorinated three‐armed star block polymer (BP) thin films using solvent vapor annealing with shear stress. The control of orientation and alignment was accomplished without any substrate surface modification. Additionally, three‐armed star poly(methyl methacrylate‐block‐styrene) [PMMA‐PS] and poly(octafluoropentyl methacrylate‐block‐styrene) were compared to their linear analogues to examine the impact of fluorine content and star architecture on self‐assembled BP feature sizes and interdomain density profiles. X‐ray reflectometry results indicated that the star BP molecular architecture increased the effective polymer segregation strength and could possibly facilitate reduced polymer domain spacings, which are useful in next‐generation nanolithographic applications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1663–1672 相似文献
68.
Anna Doppler Leo D.M. Nicholls Christopher Golz Manuel Alcarazo Michael John 《Magnetic resonance in chemistry : MRC》2019,57(11):961-967
Two functionalized [6]carbohelicenes, one of which was also available in its two enantiomeric pure forms, were oriented in stretched polystyrene in CDCl3, and in a recently introduced chiral thermoresponsive lyotropic polyaspartate (poly(benzyl)0.5(phenethyl)0.5-L-aspartate) in C2D2Cl4. From the resulting 1H,13C residual dipolar couplings, the helical pitch of a methylated [6]carbohelicene was determined and found to be in agreement with theoretical predictions and existing crystal structures (d(C2,C2′) ≈ 4.3 Å). For a second [6]carbohelicene with para-methoxyphenyl substituents, a clear conformational preference of the substituents was observed. The orientational properties of the two helicene enantiomers in the chiral polyaspartate are very similar, but both drastically change around 306 K. We suggest this behavior is due to an unusual phase transition in the liquid crystal. 相似文献
69.
Dawei Xu Li Zheng Xinhong Cheng Gang Wang Qian Wang Wenbo Xin Peiyi Ye Lingyan Shen Yuehui Yu 《Physics letters. A》2019,383(25):3134-3137
The efficient passivation of in situ NH3-plasma pre-treatment and its regulation of the band alignment between HfO2 and 4H-SiC have been investigated by XPS. With in situ NH3-plasma passivation by PEALD, a VBO of 0.72 eV and a CBO of 1.54 eV can be obtained across the HfO2/4H-SiC interface. The Si-O bonds components reduction in the passivated interface layers will lead to band bending or band shift at the interface and regulate the band alignments between HfO2 and 4H-SiC. The physical mechanism investigation of band alignments can be a cornerstone for the application of HfO2/4H-SiC heterojunctions in the high-power devices. 相似文献