• Archives of Plastic Surgery
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• 제38권3호
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• pp.279-286
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• 2011

Purpose: Chin is located in a prominent position, and is important to balance and harmony of the face. Genioplasty is widely performed with patients' high satisfaction, yet being relatively simple procedure. Recently in analysis of dentofacial trait, three rotational variables of yaw, pith, and roll are considered with three translational variables (forward/backward, up/down, right/left). And we could correct chin deformity effectively by applying the three rotational variables with three translational variables in genioplasty. Methods: Twenty-eight patients who have chin deformity underwent osseous genioplasty. Preoperative photography, facial three dimensional computed tomography, and cephalography were taken while chin deformities were accessed. The chin deformity was classified into four categories; macrogenia, microgenia, asymmetric chin deformity, and combined chin deformity groups. According to the nature of chin deformities and the patients' desire, preoperative plans were formulated, in consideration of three rotational variables and translational variables. Through intraoral approach, anterior mandible was exposed in the subperiosteal plane between the mental foramens and beneath the mental foramens. In the anterior mandible, vertical and horizontal grid lines with 5 mm intervals were marked to confirm the spatial location of osteomized bone segment after osteotomy. Chin repositioning was done in consideration of axial rotation and planar translation. Results: Most of the patients had achieved satisfactory results with few complications. By considering the three rotational variables, it was possible to make the chin repositioning effectively. One of the patients complained about insufficient chin correction. In other case, persistent sensory impairment around chin was observed. Conclusion: In conclusion, it is worthwhile to apply preoperative analysis and operative procedures in consideration of a three rotational variables with three translational variables in genioplasty.

• 한국입자에어로졸학회지
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• 제5권2호
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• pp.37-43
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• 2009

Particulate matter (PM) is one of the major indoor air pollutants especially in the subway station in Korea. In order to remove PM in the subway station, several kinds of PM removal system such as roll-filter, auto-washable air filter, demister, and electrostatic precipitator are used in the air handling unit (AHU) of subway stations. However, those systems are prone to operation and maintenance problems since the filter-regeneration unit consisting of electrical or water jet parts might malfunction due to the high load of particulates unless the filter medium is periodically replaced. In this study, the use of axial-flow cyclone was proposed for particulate filter unit in the AHU for its low operation and maintenance cost. Novel shape of axial-flow cyclone was designed by using computational fluid dynamics (CFD). The shape of vortex vane was optimized in terms of pressure drop and tangential velocity. In addition, CFD analysis was validated experimentally through the pressure drop measurement of mock-up model. We found that pressure drop and tangential velocity of fluid through the axia-flow cyclone was significantly affected by the rotating degree of vortex vane and the numerical prediction of pressure drop agreed well with experimental measurement.

• Journal of Korean Neurosurgical Society
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• 제44권1호
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• pp.8-14
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• 2008

Objective : The purpose of this study was to determine the efficacy of short segment fixation following postural reduction for the re-expansion and stabilization of unstable burst fractures in patients with osteoporosis. Methods : Twenty patients underwent short segment fixation following postural reduction using a soft roll at the involved vertebra in cases of severely collapsed vertebrae of more than half their original height. All patients had unstable burst fracture with canal compromise, but their motor power was intact. The surgical procedure included postural reduction for 2 days and bone cement-augmented pedicle screw fixations at one level above, one level below and the fractured level itself. Imaging and clinical findings, including the level of the vertebra involved, vertebral height restoration, injected cement volume, local kyphosis, clinical outcome and complications were analyzed. Results : The mean follow-up period was 15 months. The mean pain score (visual analogue scale) prior to surgery was 8.1, which decreased to 2.8 at 7 days after surgery. The kyphotic angle improved significantly from $21.6{\pm}5.8^{\circ}$ before surgery to $5.2{\pm}3.7^{\circ}$ after surgery. The fraction of the height of the vertebra increased from 35% and 40% to 70% in the anterior and middle portion. There were no signs of hardware pull-out, cement leakage into the spinal canal or aggravation of kyphotic deformities. Conclusion : In the management of unstable burst fracture in patients with severe osteoporosis, short segment pedicle screw fixation with bone cement augmentation following postural reduction can be used to reduce the total levels of pedicle screw fixation and to correct kyphotic deformities.

• 한국환경농학회지
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• 제33권3호
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• pp.178-183
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• 2014

BACKGROUND: The white stain symptom of grape clusters and canes by dust-like particles occurred in many vineyards recently. This study was conducted to investigate the ecological characteristics of white stain symptom in grapevines and vineyards. METHODS AND RESULTS: Optimal climate condition for white stain symptom was $25^{\circ}C{\sim}30^{\circ}C$ with 60% of humidity. Moreover, closed condition with same humidity showed higher incidence rate of white stain symptom than ventilation condition. Grape varieties with black berry skin such as Campbell-Early and Kyoho were more sensitive to white stain symptom compare to varieties with green and red berry skin. Although the pathogens were not detected until March, they increased from April, and increased sharply from mid of July. The pathogens may overwinter in the infected stems and/or on the bark as a mycelium. According to the increase of sugar content of grape from August to September, the mycelium which was parasitic on the bark grew to move to the fruits through the stems, and finally reached the fruit stalk to detach berries from the clusters. CONCLUSION: Well ventilation is recommended inside the vineyard since mid-July with roll up an insect net. In addition, infected stems and fruits should be removed out from grapevines infected with pathogens in the vineyards.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.480-488
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• 2000

Cabbage is the most important vegetables in korea. The cabbage production was based on arduous human labor. A comprehensive research for substituting the human work by machines has been performed at present. In general, cabbage is cultivated on hillside in korea. The harvested cabbage in a field and carrying it to a vehicle for transportation are very laborious work. Hand labor in cabbage transportation to the market damages the quality of cabbage and is also a cause to increase the cost of cabbage production. This study was to design and evaluate a prototype cabbage loader for deserving efficient and safe transportation of cabbage. The developed cabbage loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transporting and the loading of cabbage in a steep field. The maximum loading capacity of the loader was 1.0 ton. By using safety devices attached to the loader, the static slopes were 34.0% and 37.4% for the left and the rear roll-over, respectively. The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The field capacity was about 35 pallets/hr in case of picking up, carrying and unloading two cabbage pallets. The field efficiency of the loader was analyzed to be more than 8 times in comparison of the conventional human labor. The developed loader would be applied for loading and carrying the other vegetables due to the similarity of operations. The study suggested a standard approach to the design of field machines operated in a steep field.

• Archives of Plastic Surgery
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• 제32권1호
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• pp.117-123
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• 2005

The reconstructive modalities for vaginal reconstruction include simple dilatation, skin graft, use of intestinal segments and various methods using flaps. However, skin grafting procedure is the most commonly used technique and the McIndoe procedure is a representative technique among skin grafting procedures. McIndoe procedure is easier, faster and has a lower morbidity compared to other techniques. However the conventional McIndoe procedure has several problems such as incomplete vestibule formation, excessive bleeding during dissection, possibility of recto-vaginal or urethro-vaginal fistula formation, late vaginal contracture and discomfort in wearing hard plastic mold for a long time after operation. To solve these problems, the authors modified the conventional McIndoe procedure in several perspectives. The undeveloped vestibule was incised with X-shaped mucosal incision between the urethral opening and posterior margin of the vestibule and deepened by blunt finger dissection to provide a sufficient diameter & length of the neovagina and to minimize bleeding. A sizable medium thickness split skin graft was harvested and wrapped over a roll gauze-filled condom mold. Applying multiple stab incision on the skin grafted condom mold, it was inserted into the prepared neovaginal canal. Distal margin of the skin graft was secured with tips of the mucosal flaps created by X-shaped vestibular incision to prevent accidental extrusion of the skin grafted mold. During last 15 years, we applied this modification to 20 vaginal agenesis patients and investigated results of the 12 patients who could be followed up serially including hematoma formation and skin graft survival rate, size, depth, presence of late contracture, appearance, comfortness, and hygiene of the neovagina. And they were compared with 8 patients of 20 patients who underwent conventional McIndoe procedures. The modified McIndoe procedure revealed lower complication rate, higher patient satisfaction and better functional results.

• 한국항공우주학회지
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• 제34권8호
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• pp.16-23
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• 2006

본 연구에서는 스트레이크의 형상 변화가 삼각날개의 와류 상호작용과 와류 붕괴 특성에 어떤 영향을 미치는지를 규명하기 위해 세 가지의 서로 다른 평면 형상의 스트레이크를 부착한 이중 삼각 날개 형상에 대하여 유동 가시화(flow visualization)와 날개면 정압 분포 측정의 풍동실험을 수행하였다. 압력 측정 결과 스트레이크의 후퇴각이 증가할수록 날개의 상류 시위 위치에서는 보다 강력하고 집중된 와류가 형성되지만 이 와류는 시위 뒤쪽으로 진행되면서 보다 빨리 와류 붕괴(vortex breakdown)현상을 거치며 약해지는 것을 관측하였다. 가시화 결과에서는 스트레이크의 후퇴각이 증가할수록 스트레이크 와류와 날개 와류간의 roll-up 및 통합 과정이 촉진되는 것이 상류 시위에서 집중된 와류를 발달시키는 원인인 것을 확인할 수 있었다.

• 공업화학
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• 제10권8호
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• pp.1114-1118
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• 1999

플라즈마 디스플레이 패널(PDP)의 격벽(barrier rib)은 일정한 선폭과 높이를 가져 균일한 방전 공간을 제공하고, 인접한 셀 간의 전기적, 광학적 혼선(crosstalk)을 방지하기 위해 PDP의 하부 유리 기판 패널에 들어가는 구조물이다. 본 연구에서는 사진식각(photolithography)법으로 격벽을 형성하는데 필요한 감광성 격벽 페이스트가 제조되었다. 페이스트는 바인더 고분자인 에틸셀룰로오즈를 BC/BCA = 30/70 wt %인 혼합 용매에 15 wt %로 용해한 다음 관능성 단량체로서TPGDA/PETA = 50/50 wt % 혼합물, 광개시제로서 Irgacur 651 및 격벽 분말을 도입한 다음 전체를 균일하게 분산시켜 제조하였다. 감광성 격벽 페이스트의 각 성분, 조성 및 공정을 최적화하여 소성 후 높이 약 $100{\mu}m$ 에 이르는 PDP용 격벽을 고해상도로 사진식각법으로 얻을 수 있었다.

• Journal of Biosystems Engineering
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• 제37권6호
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• pp.352-358
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• 2012

Purpose: The inexpensive black box system was developed to acquire and save driving information, to give the slope information, and to transmit SOS and theft signal. Method: The device consists of a main micro controller to acquire and save data, a GPS sensor module, a CDMA module, a touch LCD module, a RF (Radio Frequency) ID module, a SD (Secure Digital) card module, an emergency electric power source, a theftproof circuit, and a sensing device. The sensing device consists of a 8 bit micro controller, a accelerometer to detect impulse, two slope sensors to detect roll and pitch angle and a circuit to detect operation of 6 lighting devices. Results: Test results are as follows: 1) a tractor can be start up only with an electronic key (password or RFID card), 2) theft signal was transmitted when a tractor moved without an electronic key, 3) SOS was transmitted at conditions that rollover or crash happened. 4) 5 more than per 1s data are recorded at 5 minute intervals as new file name in SD card. Conclusions: This system can be used to save travelling record, reduce accident, prevent theft and rescue life in the accidents.

• 마이크로전자및패키징학회지
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• 제27권2호
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• pp.19-26
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• 2020

Flexible displays have been evolved into curved, foldable, and rollable as the degree of bending increases. Due to the presence of brittle electrodes (e.g. indium-tin oxide (ITO)) that easily cracked and delaminated under severe bending deformation, lowering mechanical stress of the electrodes has been critical issue. Because of this, mechanical stress of brittle electrode in flexible displays has been analyzed mostly in terms of bending radius. On the other hand, in order to make rollable display, various mechanical components such as roller and spring are needed to roll-up or extend the screen for the rollable display apparatus. By these mechanical components, brittle electrode in the rollable display is subjected to the excessive tensile stress due to the retracting force as well as the bending stress by the roller. In this study, mechanical deformation of rollable OLED display was modeled considering boundary conditions of the apparatus. An analytical modeling based on the classical beam theory was introduced in order to investigate the mechanical behavior of the rollable display. In addition, finite element analysis (FEA) was used to analyze the effect of mechanical components in the apparatus on the brittle electrode. Furthermore, a strategy for improving the mechanical reliability of the rollable display was suggested through controlling the stiffness of adhesives in the display panel.