• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.279.2-279.2
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• 2016

InGaN/GaN multiple quantum wells (MQWs) have been attracted much attention as light-emitting diodes (LEDs) in the visible and UV regions. Particularly, quantum efficiency of green LEDs is decreased dramatically as approaching to the green wavelength (~500 nm). This low efficiency has been explained by quantum confined Stark effect (QCSE) induced by piezoelectric field caused from a large lattice mismatch between InGaN and GaN. To improve the quantum efficiency of green LED, several ways including epitaxial lateral overgrowth that reduces differences of lattice constant between GaN and sapphire substrates, and non-polar method that uses non- or semi-polar substrates to reduce QCSE were proposed. In this study, graded short-period InGaN/GaN superlattice (GSL) was grown below the 5-period InGaN/GaN MQWs. InGaN/GaN MQWs were grown on the patterned sapphire substrates by vertical-metal-organic chemical-vapor deposition system. Five-period InGaN/GaN MQWs without GSL structure (C-LED) were also grown to compare with an InGaN/GaN GSL sample. The luminescence properties of green InGaN/GaN LEDs have been investigated by using photoluminescence (PL) and time-resolved PL (TRPL) measurements. The PL intensities of the GSL sample measured at 10 and 300 K increase about 1.2 and 2 times, respectively, compared to those of the C-LED sample. Furthermore, the PL decay of the GSL sample measured at 10 and 300 K becomes faster and slower than that of the C-LED sample, respectively. By inserting the GSL structures, the difference of lattice constant between GaN and sapphire substrates is reduced, resulting that the overlap between electron and hole wave functions is increased due to the reduced piezoelectric field and the reduction in dislocation density. As a results, the GSL sample exhibits the increased PL intensity and faster PL decay compared with those for the C-LED sample. These PL and TRPL results indicate that the green emission of InGaN/GaN LEDs can be improved by inserting the GSL structures.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.183.1-183.1
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• 2010

Recently, the increased interest in environmental issues has led to extensive research for development of green energy generation systems. However, only one type of generation system may not be sufficient for stand-alone mode because it cannot cope with the irregularity of weather condition. A hybrid generation system is able to make up for the weakness of each system. In this paper, a stand-alone hybrid wind/PV system is developed that can guarantee the stable energy supply. The system is suitable for power supply under 50W, and a vertical savonius type of blade was designed and applied for the wind generation system.

• Journal of Oral Medicine and Pain
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• 제11권1호
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• pp.19-27
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• 1986

Registration of the mandibular movement in patients with temporomandibular joint noise (clicking and/or crepitus) was performed using one of mandibular tracking devices(SAPHON VISI-TRAINER CII,Tokyo Shizai-sha Inc.,Japan). The obtained results were follows : 1. In many cases, the movement pattern of light emitting diode(LED) attached on the mandibular midline showed lateral deviation from a vertical reference line which was pronounced in association with TMJ noise during opening and closing. 2. In patients with unilateral TMJ noise the mandibular midline usually towards the side demonstrating TMJ noise during opening. 3. A distinct V-shaped discontinuity in the trace of velocity of mandibular movement was found at the point of the TMJ noise. 4. In patients with TMJ noise the velocity of mandibular movement at the point of the TMJ noise was decreased rapidly. 5. In several cases, TMJ noise could be eliminated by traning of Rocabado`s control of TMJ rotations.

• 대한후두음성언어의학회지
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• 제20권2호
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• pp.126-130
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• 2009

Arytenoid motion has long been recognized as complex. Misunderstandings about the specifics of arytenoid motion remain prevalent. The resultant misunderstandings have led to erroneous or suboptimal clinical approaches to the treatment of vocal fold immobility. A thorough understanding of the anatomy of the arytenoid and cricoid cartilages, the cricoarytenoid joint, and related ligaments, muscles, and other structures is essential in order to fully understand laryngeal motion disorders. Arytenoid motion occurs in three directions. Movements involving a change anteriorly and posteriorly, as well as vertically, are due to the revolving or pitchlike motion of the arytenoid along the minor axis of the cricoid's elliptically shaped facet. The medial and lateral movements are due to the orientation of the arytenoid which in turn is determined by the forward, lateral, and inferior inclination of the cricoid-arytenoid facet. During adduction it is the outward angulation of the vocal process from the body of the arytenoid that allows the entire length of the vocal proceses to approximate one another and to have this meeting occur at the proper vertical height.

• 대한전자공학회논문지
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• 제26권6호
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• pp.124-130
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• 1989

ITIC를 중심으로 고밀도 DRAM을 위한 획기적인 밀도 향상을 기할 수 있는 공정과정과 회로디자인의 기술 혁신에 대하여 지다이너 입장에서 논의하였다. 여기서 개발한 TETC라 부르는 DRAM은 trench 기술과 SEG기술을 이용하였는데 $n^+-polysilycon$인 storage 전극과 $n^+-source$ 전극이 self-con-tact되고 soft error 를 극복할 만큼 충분히 큰 정전용량을 갖으므로 절연 영역을 따라서 만든 수직의 캐패시터를 이용함으로써 셀 크기를 기존의 BSE cell구조에 비하여 약 30% 감소되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1144-1148
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• 2007

Seoul Metro is celebrating 32 anniversary this year and through developments over the years it is being evaluated as the 3rd in the world in operational sizes, the 4th in the world in facility sizes, it transports about 4 million passengers per day and it is now a vital public transportation means. However, the track maintenance organization and manpower structures along with technology cooperative office were led by unions that do not like changes and overshadows the trends of changes by expanding organizations and recruiting personnels and it is going against the current of times. Thus, it is time when a break point is required for breaking away from labor-intensive methods of the past that rely on hand works and vertical organizational structures. Therefore, this study investigates the states of national.international track maintenance operations and examines and analyzes the problems so that it can be utilized as base data for efficiently operating the organizations and maintenance works on track fields.

• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.627-632
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• 2016

In this paper, we propose a new vision-based defect inspection system for the surface of hot slabs. To minimize the influence of self-emission from slab surfaces with high temperature, an optic method based on blue LED light and a blue pass filter is proposed. Because the slab surface is partially covered with scales, which are unavoidable oxidized substances caused during manufacturing, it is difficult to distinguish between vertical cracks and scale. In order to resolve this problem and to improve the detection performance, the use of a Gabor filter and dynamic programming are proposed. Finally, the effectiveness of the proposed method is shown by means of experiments conducted on images of hot slabs that were obtained from an actual slab production line.

• 한국중재학회지:중재연구
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• 제13권2호
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• pp.489-517
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• 2004

The resolution of the 1993 Uruguay Round and the opening of Korea's construction market in '97 marked the beginning of the globalization of Korea's domestic construction market. Consequently, the process led to changes in contracting procedures, as well as disputes in construction management. With globalization came a rapid realization of reasonable values, which forced the hierarchical vertical relationship between the owners, constructors, and subcontractors into a more equal, horizontal relationship. Once the hierarchical relationship was altered, the late 1990's witnessed a dramatic increase in managerial disagreements, in addition to escalating legal disputes and expenditures. The horizontal relationship was a new concept and brought forth many complexities. Unfortunately, because all of this was new, management of construction disputes was elementary at best. Anticipation of disputes is the key to effective dispute management. This includes thorough reviews of contract documents, document management, construction records, and checklists. Also necessary is the education of owners and contractors with pertinent knowledge concerning dispute management. The following paper focuses on the importance of observing construction disputes in order to facilitate management thereof.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.82-90
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• 2003

The advance in technology of the CWR in Korea has led the establishment of the CWR on the sharp curve (i.e. less than R=600m). As thermit welding used in the sharp-curved construction site is carried out on the curve track, it is difficult to adjust a curve shape accurately and these difficulties have occurred in a number of cases. Therefore, in this study, the lateral buckling analysis of CWR track was carried out considering the actual ballast resistance force. In addition, the cant and vertical resistance force in ballast was considered in order to predict the initial behaviour of bucking in track under the more accurate method.

• 한국기계기술학회지
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• 제13권3호
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• pp.49-55
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• 2011

For the purpose of the enhancement of the air conditioner performance and fuel effciency, several cases of centrifugal impeller for passenger car air conditioner have been numerically analyzed by changing central angle of blades and length of outlet for shape optimization of the impeller. Commercial CFD program Fluent 6.3.26 has been used to compute velocity, temperature, pressure and turbulence intensity that can lead numerous results. The central angles of two blades and three cases of outlet length led 4~12% and 3.5~6.4% differences of velocity and flow rate, respectively. The velocity distribution near the blade surface was axisymmetric and had a maximum value of 22.19 m/s and velocity of the vertical direction of the impeller showed linear increase with horizontal direction. At case 3 of oultet length, there existed a a minimum pressure value of -133320 Pa.