• Elastomers and Composites
• /
• v.50 no.2
• /
• pp.119-125
• /
• 2015

Because of their low surface free energy and absence of polar groups at the surface, polyolefins are substrates whose wetting and adhesion are very difficult. Free radical grafting of monomers to backbone polymer is one of the most attractive ways for the chemical modification of polymers. Synthesis of graft copolymer through graft polymerizations of PE and/or PP with phthalic anhydride (PhAn) was made and FTIR spectra of the graft polymer were the examined. And also the effects of phthalic anhydride content on the grafting ratio, thermal properties and contact angle of the graft polymer were examined.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.948-950
• /
• 2009

A few organosilicon compounds (OC) - both cyclic and linear siloxanes with different structure of the substituents - have been synthesized. Properties of the LC anchoring on OC films have been measured. The OC investigated provide the homogeneous planar alignment with LC tilt angle in the range from $0.7^{\circ}$ to $1.9^{\circ}$. An increase of the microrelief depth results in a small increase of the tilt angle. The azimuthal anchoring is better for the films of the OC without molecular microrelief or the OC comprising polar groups.

• Korean Journal of Optics and Photonics
• /
• v.30 no.4
• /
• pp.159-166
• /
• 2019

The trajectory of the transmission ellipsometric pseudoconstant ${\rho}=tan{\psi}_{\mu}e^{i{\Delta}_{\mu}}$ of a uniaxially anisotropic substrate like PET forms a circle in polar coordinates, as the phase-retardation angle is varied at a fixed azimuthal angle. The radius as well as the center's position of this circle are functions of the azimuthal angle only. This circle passes through the point (1,0), and the center of this circle is located on the real axis. These characteristics of the circle are examined analytically, and are utilized to derive simple expressions for the azimuthal angle and the phase-retardation angle of the uniaxially anisotropic substrate using the measured transmission ellipsometric constant. Finally, we confirm that the derived expressions are well applied to the analysis of the optical anisotropy of a PET film.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.898-899
• /
• 2008

In this paper we propose a new method for obtaining two way switchable LCD. For this two domain vertical alignment LCD is used. A two way LCD is able to show different images on the same screen based on left and right perspectives. Viewing angle dependence of different grey levels of transmittance for the polar angles 0, +45 and -45 degree are also found out.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.157-162
• /
• 2007

Geophysical survey has been conducted on the continental margin off the South Shetland Islands aboard R/V Onnuri of KORDI in 1992/1993. About 800-line km of 96-channel reflection data have been acquired. On the seismic section, BSR with strong reflectivity and negative polarity has been found at 700 ms below the sea bottom. BSR is considered as the base of gas hydrates and AVO analysis was performed to study physical properties along BSR. True amplitude recovery and surface consistence amplitude were applied to seismic data and angle gathers were obtained. AVO gradient and AVO intercept are calculated on every CDP gather. Section of AVO intercept show strong reflectivity and negative polarity on BSRs and stronger continuity of BSR than stacked section. Cross plot of intercept-gradient indicates that the lower layer below BSR is filled with free gas.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.294-296
• /
• 2022

Atherosclerosis is a chronic vascular inflammatory disease in which plaque builds up in the arteries and impairs blood flow. This can lead to heart disease and stroke. Since most people do not have any symptoms until the artery is severely narrowed, early detection of atherosclerosis is critical. In this paper, in order to effectively detect atherosclerotic lesions in tube-shaped blood vessels, polar conversion is applied to MRI images based on the vessel center. We then propose a SE-LSTMNet model using continuous signal information for each angle of a polar coordinate image. The trained model showed classification performance of 0.9194 accuracy, 0.9370 sensitivity, 0.8796 specificity, 0.8700 F1 score, and 0.9719 AUC on the validation data.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.1
• /
• pp.131-137
• /
• 1986

Cutting oil cools the chip and a tool as well as lubricates the chip-tool interface, the flank and machined surface. Rehbinder effect has been known as a phenomenon, the reduction of mechanical strength, when the metal is exposed to a polar organic environment or the surface of metal is coated with some polar organic substances. About the cause of Rehbinder effect there have been many different ideas by Rehbinder, Shaw, Barlow, Sakida and etc. In this report, the efect of polar organic substance( $C_{6}$ $H_{5}$C $H_{3}$+ $C_{6}$ $H_{4}$(C $H_{3}$)$_{2}$+ $C_{4}$ $H_{9}$OH+ $C_{6}$ $H_{12}$ $O_{2}$) (magic ink) upon the mechanism of chip formation on the orthogonal cutting of copper and mechanical properties of the work material are experimentally discussed with various rake angles. As expected no lubrication action could be noticed, but the shear angle increased and the cutting force and shear strain on the shear plane decreased, therefore the work material must be embrittled under polar organic substance.substance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.12
• /
• pp.1101-1104
• /
• 2008

We have studied electro-optic characteristics to improve viewing angle of the in-plain switching (IPS) liquid crystal display using an compensation film. The IPS mode shows relatively large light leakage and color shift in diagonal directions in a dark state. To solve this problem, we have compensated the low contrast ratio in diagonal directions using one optimized discotic film and adjusting TAC films of polarizers. The compensated IPS mode shows wide viewing angle characteristics that region of CR 50:1 is over $60^{\circ}$ of polar angle in all directions. The optimized IPS cell exhibits much better performances than other methods do in terms of CR and color uniformity.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.2
• /
• pp.69-79
• /
• 1994

The conventional machine vision system which has uniform rectangular grid requires tremendous amount of computation for processing and analysing an image especially in 2-D image transfermations such as scaling, rotation and 3-D reconvery problem typical in robot application environment. In this study, the imaging system with nonuiformly distributed image sensors simulating human visual system, referred to as Ploar Exponential Grid(PEG), is compared with the existing conventional uniform rectangular grid system in terms of image resolution and computational complexity. By mimicking the geometric structure of the PEG sensor cell, we obtained PEG-like images using computer simulation. With the images obtained from the simulation, image resolution of the two systems are compared and some basic image processing tasks such as image scaling and rotation are implemented based on the PEG sensor system to examine its performance. Furthermore Fourier transform of PEG image is described and implemented in image analysis point of view. Also, the range and heading-angle measurement errors usually encountered in 3-D coordinates recovery with stereo camera system are claculated based on the PEG sensor system and compared with those obtained from the uniform rectangular grid system. In fact, the PEC imaging system not only reduces the computational requirements but also has scale and rotational invariance property in Fourier spectrum. Hence the PEG system has more suitable image coordinate system for image scaling, rotation, and image recognition problem. The range and heading-angle measurement errors with PEG system are less than those of uniform rectangular rectangular grid system in practical measurement range.

• Elastomers and Composites
• /
• v.37 no.1
• /
• pp.49-56
• /
• 2002

Polypropylene is oxidized with UV/ozone as a function of UV treatment time and ozone flow rate and its surface characteristics are investigated using contart angle measurements and XPS. The aging behavior of oxidized surface is investigated under air, water and ethylene glycol as the aging media. Adhesion strength is also investigated using a lap shear test. Polar surface energy increases with increasing UV/ozone treatment time as well as ozone flow rate. No polar surface energy change is observed under water aging, while under air aging it decreases significantly within 2-3 days and reaches the close value as that of the untreated PP. Adhesion strength increases with increasing UV/ozone treatment time as well as ozone flow rate.