• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.426-429
• /
• 2005

The fringe-field switching (FFS) mode associated with a transition from a homogenously aligned to twist deformation require rubbing process. In this devices, $1^o$ of misalignment in an azimuthal direction could cause voltage-dependent transmittance (V-T) to be different from that in a normal area and consequently results in a rubbing mura. According to our studies, the single domain FFS cells are much more sensitive to the rubbing mura than the dual domain FFS cell. Moreover, the FFS cells with negative LC are much more sensitive to the rubbing mura than the FFS cells with positive LC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.12 no.1
• /
• pp.81-87
• /
• 1999

The surface morphology of liquid crystal alignment layer has been investigated by using Brewster angle microscope(BAM) for the first time. The samples used in this work for liquid crystal alignment layer were mechanically rubbed polyimide films. The rubbing pattern on this layer has been analyzed with the terms of microgroove and rubbing induced optical birefringence. For the mechanically rubbed surface, the geometrical factors of microgroove play the major role for the formation of rubbing pattern. We propose that the BAM can be used as a powerful tool not only for observing the rubbing pattern, but also for inspecting the surface defects.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.26 no.6_spc
• /
• pp.714-720
• /
• 2016

Rubbing and misalignment are the most usual faults that occurs in rotating machinery and with them severe effect on power plant availability. Especially blade rubbing is hard to detect on FFT spectrum using the vibration signal. In this paper, the possibility of feature analysis of vibration signal is confirmed under blade rubbing and misalignment condition. And the lab-scale rotor test device provides the blade rubbing and shaft misalignment modes. Feature selection based on GA (genetic algorithm) is processed by the extracted feature of the time domain. Then, classification of the features is analyzed by using SVM (support vector machine) which is one of the machine learning algorithm. The results of features selection based on GA compared with those based on PCA (principal component analysis). According to the results, the possibility of feature analysis is confirmed. Therefore, blade rubbing and shaft misalignment can be diagnosed by feature of vibration signal.

• Journal of Korean Society of Forest Science
• /
• v.103 no.3
• /
• pp.510-518
• /
• 2014

Conflicts between humans and wild boars (Sus scrofa) have increased because of causing crop damage and appearing in downtown. Management to reduce population size has mostly been implemented on pests, but knowledges about ecological values are very rare. Rubbing trees by wild boar was investigated to figure out characteristics and for management ecologically from July to October 2013 in a mixed forest, Geochang, Gyeongnam Province, Korea. Pinus rigida was most frequently founded, and rubbing trees, both conifers and deciduous, were mainly located in 200~600 m above sea level. DBH was no significant difference between rubbing and control trees. The use intensity of conifers was higher than that of deciduous. The coverage of foliage layers and the number of woody plants within a radius of 2.5 m of trees (rubbing and control) were also investigated and compared to determine ecological characteristics. There were 1,332 individuals founded from 25 families. In the coverage of foliage layers, the understory and midstory showed statistically significant, but not in the subover and overstory. The number of Shrubs and saplings are higher in rubbing trees than those of control, but no difference in stems. Total individuals, the number of species, species diversity index(H') within a radius 2.5 m is considerably higher in rubbing trees with high intensity than those of low intensity and control. Our results show that wild boar mainly selected and used conifers more frequently as rubbing trees. Wild boar also modified the physical environments around rubbing trees. Consequently, the positive effects such as species diversity is increase. Thus the conservation policies is required after the intensive population reduction every 3-4 years for forest ecological management rather than annual sustainable hunting.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.5
• /
• pp.570-575
• /
• 2020

In this study, to develop balloon flower (Platycodon grandiflorum) leaves, which are not used as tea, a method of making green tea was referred to, and several physiological activities were analyzed using the balloon flower leaf tea with different times of roasting and rubbing. The highest total polyphenol and tannin contents were 33.02 mg GAE/g and 5.03 mg/g at two times of roasting and one time of rubbing, respectively. In the case of the total flavonoids, the RO3 + RU2, subjected to three times of roasting and two times of rubbing, showed the highest value, whereas there was no significant difference between the control and the other samples. Except for the green tea as a control, the RO2 + RU1 samples reported the highest antioxidant activity whereas it decreased with increasing number of times of roasting and rubbing. The color, lightness, and yellowness tended to decrease slightly as the number of increasing roasting and rubbing among the samples with no significant difference. All of these things together, to develop tea using the balloon flower leaves would be suitable with two times of roasting and one time of rubbing.

• Journal of Power System Engineering
• /
• v.3 no.1
• /
• pp.5-8
• /
• 1999

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.330-330
• /
• 2008

It is widely investigated to liquid crystal (LC) alignment using non-contact alignment method such as ion-beam (IB) irradiation, UV alignment, and oblique deposition. Because conventional rubbing method has some drawbacks. These include defects from dust and electrostatic charges and rubbing scratch during rubbing process. In addition, rubbing method needs additional process to remove these defects. Therefore rubbing-free methods like ion-beam irradiation are strongly required. We studied LC alignment effect on poly imide surface by IB irradiation and electro-optical (EO) characteristics of twisted nematic liquid crystal display (TN-LCD). In this experiment, a good uniform alignment of the nematic liquid crystal (NLC) with the ion-beam exposure on the polyimide (PI) (SE-150 from Nissan Chemical) surface was observed. We also achieved low pretilt angle as a function of ion-beam irradiation intensity. In addition, it can be obtained the good EO properties of the IB-aligned TN-LCD on PI surface. Some other experiments results and discussion will be included in the poster.

• Textile Coloration and Finishing
• /
• v.32 no.1
• /
• pp.19-26
• /
• 2020

The previous study reported that the quaternary copolymer of MMA, BA, MAA, and NEA was expected to be a good monomer composition for a binder polymer with good rubbing fastness for digital textile printing(DTP) pigment ink. However, the rubbing fastness of the dyed fabric with the quaternary copolymer binder containing pigment ink is not enough to be commercially used. Therefore, this study aims to optimize MMA:BA:MAA:NEA composition for improved rubbing fastness. And the binder polymer with various MMA:BA:MAA:NEA compositions were synthesized using miniemulsion polymerization. The particle size, viscosity, molecular weight, and Tg of the synthesized binder were evaluated. And the color strength and rubbing fastness of the black pigment ink dyed cotton fabrics with the prepared binders were also evaluated. Then, the stiffness of undyed and dyed cotton fabrics were evaluated to investigate the changes in touch as the binder structure changes.

• Elastomers and Composites
• /
• v.58 no.1
• /
• pp.1-10
• /
• 2023

In this study, we investigate the liquid crystal (LC) alignment of LC cells created from plant-based polysaccharide derivatives, such as guar gum. Guar gum films exhibit satisfactorily high optical transparency in the visible light region (400-750 nm). For example, the transmittance of polyimide films, which are the most typically used LC alignment layers, is 87%, whereas that of guar gum films deposited onto a glass substrate at a wavelength of 550 nm is approximately 99%. The observed LC alignment depends on the rubbing depth. For example, an LC cell comprising a guar gum film fabricated via rubbing at rubbing depths of 0.1, 0.2, 0.3, and 0.4 mm exhibits a planar LC alignment, whereas it exhibits a vertical LC alignment at a rubbing depth of 0.5 mm. Additionally, the LC alignment is shown to be correlated with the total surface energy of the guar gum films. When the total surface energy of a rubbed guar gum film exceeds 58.10 mJ/m², an LC cell comprising the guar gum film exhibits a stable and vertical LC alignment. Therefore, guar gum can be used to realize the vertical alignment system of LC via a simple adjustment of the rubbing depth.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.446-449
• /
• 2005

The alignment property of liquid crystals on the two-easy axes substrate is investigated. The two-easy axes substrate frustrates the orientation of the LCs next to the substrate, and hence influences the birefringence of the LC cell. Experimental findings reveal that the ratio of the rubbing strengths in the different rubbing directions and the cell thickness substantially influence the birefringence of the LC cell. The surface anchoring energetic competition between the different rubbing directions contributes to the observed results.