• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.430-430
• /
• 2007

In general, polyimides (PIs) are used in liquid crystal displays (LCDs) as alignment layer of liquid crystals (LCs). Up to date, the rubbing alignment technique has been widely used to align liquid crystals on the PI surface, which is suitable for mass-production of LCDs because of its simple process and high productivity. However, this method has some disadvantages. Rubbed PI surfaces include the debris left by the cloth and the generation of electrostatic charges during rubbing process. Therefore, rubbing-free techniques for LC alignment are strongly required in LCD technology. In this experiment, PI was uniformly coated on indium-tin-oxide electrode substrates to form LC alignment layers using a spin-coating method and the PI layers were subsequently imidized at 433 K for 1 h. The thickness of the PI layer was set at 50 nm. The LC alignment layer surfaces were exposed to an $Ar^+$ ion-beam under various ion-beam energies. The antiparallel cells and twisted-nematic (TN) cells for the measurement of pretile angle and electro-optical characteristics were fabricated with the cell gap of 60 and $5\;{\mu}m$, respectively. The LC cells were filled with nematic LC (NLC, MJ001929, Merck) and were assembled. The NLC alignment capability on ion-beam-treated PI was observed using photomicroscope and the pretilt angle of the NLC was measured by the crystal-rotation method at room temperature. Voltage-transmittance (V-T) and response time characteristics of the ion-beam irradiated TN cell were measured by a LCD evaluation system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.358-365
• /
• 2017

In this paper, we propose an object recognition method using image information to improve the efficiency of visual servoingfor industrial manipulators in industry. This is an image-processing method for real-time responses to an abnormal situation or to external environment change in a work object by utilizing camera-image information of an industrial manipulator. The object recognition method proposed in this paper uses the Otsu method, a thresholding technique based on separation of the V channel containing color information and the S channel, in which it is easy to separate the background from the HSV channel in order to improve the recognition rate of the existing Harris Corner algorithm. Through this study, when the work object is not placed in the correct position due to external factors or from being twisted,the position is calculated and provided to the industrial manipulator.

• Animal Systematics, Evolution and Diversity
• /
• no.nspc5
• /
• pp.71-79
• /
• 2005

Two hypotrichous ciliates inhabiting the representative terrestrial habitats of Jindo Island, Holostichides chardezi Foissner, 1987 and Rigidocortex octonucleatus (Foissner, 1988) are found from Jindo Island. These two species are newly recorded from Korea. The description was based on the observation of living specimens, protargol impregnated specimens and biometric analysis. The morphological variations among the populations of these species were investigated with morphometry. The diagnostic characteristics of these species are as follows: Holostichides chardezi : elongate body flexible and twisted, yellowish subpellicular granules scattered entire cortex, adoral zone of membranelles covering about $28\%$ of body length, left and right rows of mid-ventral cirri paired, left row ended at buccal vertex and right row extending to center of body, no transverse cirri, both marginal rows of cirri not confluent at posterior end, 28-42 macronuclei and 1-5 micronuclei scattered entire body. 3 caudal cirri and 4 dorsal kineties. Rigidocortex octonucleatues: elongate-oval body rigid and not contractile, yellowish cytoplasmic crystals and fat globules densely packed, adoral zone of membranelles covering about $40\%$ of body length, 5 transverse cirri, both marginal rows of cirri not confluent at posterior end, 8 macronuclei longitudinally arranged in median of cell, 3 caudal cirri and 7-10 fragmented dorsal kineties.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.6
• /
• pp.210-218
• /
• 2019

Recently, cable-stayed bridges have been attempting to apply bold and experimental shapes for aesthetic and originality. In the case of bridges that have no similar cases, deep understanding and verification of analytical modeling is needed. S-shaped curved pedestrian cable-stayed bridge is always twisted because the cable is arranged on one side of the inverted triangular truss girder. In order to suppress the torsion, the Link-shoes are arranged at the left and right top members with reference to the Bearing placed at the mid-bottom member. The first research is related to the modeling method of Link-Shoe and Diaphram. In order to accurately reflect the transverse structural system and the torsional stiffness, it was necessary to model the Link-Shoe and the Diaphram directly rather than indirectly using the stiffness of the Bearing. The second study is related to the lateral arrangement of Bearing and Link-Shoes. Method 1 is to place in order of Link-shoe, Bearing, and Link-shoe from outside the curve radius. Method 2 is place to in order of Bearing, Bearing, and Link-shoe. In method 2, compared to method 1, the stress in the outer top member was larger and the stress in the inner one was decreased. It is analyzed that the stress adjustment is possible according to the lateral arrangement of Bearing and Link-Shoe.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.4
• /
• pp.106-119
• /
• 2014

The $76^{th}$ National Treasure is consisted of seven volumes of Nanjung Ilgi (War Diary of Admiral Yi Sun-sin; each titled by the author based on the zodiac name of the year covered, i.e. Imjin Ilgi, Gyesa Ilgi, Gabo Ilgi, Byeongsin Ilgi, Jeongyu Ilgi, Sok Jeongyu Ilgi, Musul Ilgi), Seogancheob (Letters of Admiral Yi) and Imjin Jangcho (Drafts of Imjin War Reports of Admiral Yi). These are currently in the custody of Hyeonchungsa shrine, the state-managed memorial shrine of Admiral Yi, and has been added to UNESCO's Memory of the World Register in June 2013 in the appreciation of its historical and academic importance as a commander's hand-written battlefield accounts during Japanese invasions of Korea. Imjin Jangcho, among these nine volumes, is a record of battles, including observations on the enemy fleets, suggestions on naval matters, battle expenditure, and methods of battle preparation, transcribed by someone else according to Admiral Yi's instructions. It is Admiral Yi's honest detailobservations on the war situation during Japanese invasions of Korea from 1592 as a Naval Commander of Left Jeolla Province, till 1594 (Year 27 of King Seonjo's reign) as a Commander-in-Chief of the Naval Forces of the South. It is a draft of the war report to be submitted to the King in a single volume as a folio (each sheet folded once to produce one leaf) bound in a side-stitched binding with five holes and inner binding of twisted paper. This study explores the condition and the treatment performed on Imjin Jangcho which could have an implication for the conservation of cultural assets on paper of late Joseon Dynasty.

• Korean Journal of Heritage: History & Science
• /
• v.54 no.3
• /
• pp.52-67
• /
• 2021

This study is an attempt to explore the roles of and the collaborative relationship between Daheojang and Maedeupjang. Daheojang and Maedeupjang share a similar manufacturing process. However, in modern times, Daheojang totally disappeared, and Maedeupjang was designated as an intangible cultural property. The present study will investigate the role of Daheojang and Maedeupjang based on the literature of the Joseon dynasty. Daheojang were craftsmen who made bands and strings of woven or twisted silk strands. They made mangsu and tassels or made knots to produce magnificent artifacts. Maedeupjang complete all steps of the process, from refining, dyeing, combining threads, daheo, maedeup, to the tassel. Daheojang in the Joseon dynasty was the center of this process. Daheojang belonged to almost all Uigwe because it used items ranging from large uso to cushion straps. Dahoe is a craft with various items and techniques. It has been widely used to produce majestic items like formal dresses, ritual ceremony pieces, and mountings, as well as daily items like jodae, pocket straps, and norigae. Based on the records of Uigwe in the late Joseon dynasty, the study explored the collaborative relationship between Daheojang and Maedeupjang. Sambang, the room where both Daheojang and Maedeupjang belong, was the room to produce the royal chair. The royal chair essentially includes large uso. The large uso is an artifact that ties a knot in a thick circle more than two meters long. While Daheojang made rounded daheo, Maedeupjang made delicate and balanced knots. Also, they produced royal inscriptions together with a royal seal with decorative mangsu and a seal of thick rounded daheo. In order to learn about traditional technology, it is necessary to study the system of the times and social trends. Therefore, the study focused on Daheojang, who were common master craftsmen during the Joseon dynasty but now are not familiar to most people.

• Journal of the Korean Institute of Gas
• /
• v.25 no.2
• /
• pp.22-27
• /
• 2021

This paper is a purpose to study the failure examples for LPG vehicle. The first example, the researcher certified the incongruity phenomenon decreased engine power by ignition fire leakage because of spark plug threaded part damage assembling in cylinder head. The second example, the timing mark that accurately adjusting the camshaft and crankshaft position were twisted about 0.5 block each other. Finally, the researcher seeked the disharmony phenomenon as it couldn't set ignition timing. The third example, the researcher knew the failure phenomenon by interrupted the closing period for intake valve moving with air flow in the number 3 port of cylinder head as the foreign substance in cylinder head didn't remove. Therefore, the manager of a car has to thorough going inspect and the manufacture of a car must remove the cause of failure with quality assurance.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.5
• /
• pp.535-539
• /
• 2022

This study analyzed the efficient hose loading method for indoor fire hydrants, and the experimental results are as follows. An effective fire hose loading method is to be derived through an experiment comparing the fire hose loading method of an indoor fire hydrant and the speed of fire suppression. When the fire hose was loaded by folding, it took an average of 33 seconds to load the fire hose, and for the hangyeopsal, it took an average of 69 seconds to load the fire hose, showing a significant difference. First, in the folding hose deployment experiment, subjects A, C, D, and E showed similar values from 34 seconds to 37 seconds, respectively. The reason seems to be the result of the fact that the fire hose was not twisted when unfolding, and that it was possible to deploy the hose smoothly. Subject B showed the lowest deployment time at 25 seconds, which seems to be the result of B's experience in deploying the fire hose. Second, in the hose unfolding experiment, subjects A, B, C, and E had a similar time period of 44 to 76 seconds, respectively. However, the test subject D was significantly higher at 110 seconds. The reason is that the attempt to prevent hose kinking when deploying the fire hose and the unstable psychological state through tension are judged to increase the fire hose deployment time.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.36 no.4
• /
• pp.213-220
• /
• 2023

This paper presents a model simulating the folding process and collision dynamics of "ddakji", a traditional Korean game played using paper tiles (which are also referred to as ddakji). The model uses two A4 sheets as the base materials for ddakji. The folding process involves a series of boundary conditions that transform the wing part of the paper structure into a twisted configuration. A rigid plate boundary condition is also adopted for squeezing, establishing the shape and stress state of the game-ready ddakji through dynamic relaxation analysis. The gaming process analysis involves a forced displacement of the striking ddakji to a predetermined collision position. Collision analysis then follows at a given speed, with the objective of overturning the struck ddakji--a winning condition. A genetic algorithm-based optimization analysis identifies the optimal collision conditions that result in the overturning of the struck ddakji. For efficiency, the collision analysis is divided into two stages, with the second stage carried out only if the first stage predicts a possible overturn. The fitness function for the genetic algorithm during the first stage is the direction cosine of the struck ddakji, whereas in the second stage, it is the inverse of the speed, thus targeting the lowest overall collision speed. Consequently, this analysis provides optimal collision conditions for various compression thicknesses.

• The korean journal of orthodontics
• /
• v.32 no.4 s.93
• /
• pp.275-291
• /
• 2002

Of various factors indicated for effective use of straight wire appliances, there was a great lack of studies both domestic and international about the curvatures of tooth crowns. This study was performed to investigate the labio/buccal clinical crown curvatures of Korean permanent teeth. For this study, three-dimensional laser scanning was performed on 36 dental casts with normal anatomic structures. Andrews plane and Facial axis of clinical crown (FACC) were designated as horizontal and vertical reference planes respectively. 2 or 3 lines, 1mm apart, were drawn superior, inferior, left and right of these reference planes. A three-dimensional coordinate table was made for points formed by crossing these lines, and averages of each coordinate point on the 36 dental casts were obtained. The curvature equation was made using three-dimensional coordinate points (x,y,z) and by this curvature equation, the curve ratio of each tooth was obtained. Curve ratio changes of each section of teeth were calculated by curve ratios of simplified curves. These two dimensional curves were simplified horizontally and vertically Conclusions for this study are as follows. 1. The basic data of labial and buccal clinical crown curvatures were obtained about Korean permanent teeth. 2. No significant difference was found between male and females. 3. Individual tooth characteristics 1) In maxillary central incisors, the difference in the curve ratio between the gingival and incisal sides was greater than for the other teeth. And the gingival side showed a greater curve ratio. 2) Maxillary canines showed more curvatures in the mesio-occlusal surface than the other surfaces. 3) In maxillary $1^{st}$ premolars, more curvatures were found in mesio-occlusal and disto-gingival surface, thus showing a twisted crown surface, but in maxillary $2^{nd}$ premolars, the crown curvatures of mesial and distal ends became parallel to each other. 4) No significant difference in crown curvatures was found between mandibular central and lateral incisors. 5) Occluso-gingival curvatures of mandibular$2^{nd}$ premolar turned out to be more rounded than mandibular $1^{st}$ premolars or maxillary $2^{nd}$ premolars. From the above conclusions, it can be deduced that the same bracket bases can be used for mandibular central and lateral incisors. But for maxillary $1^{st}\;and\;2^{nd}$ premolars and for mandibular $1^{st}\;and\;2^{nd}$ premolars, because crown curvatures showed significant differences, when making bracket bases there is ample reason to make bracket base curves differently for each type of tooth.