• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.480-480
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• 2007

A large diameter plasma filled backward wave oscillator is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is high beam energy. Plasma is produced by the beam and it has favorable effects on beam propagation and Cerenkov oscillation.

• 한국지반신소재학회논문집
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• 제22권1호
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• pp.75-85
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• 2023

굴착공사가 이루어지는 지역에서는 지하수위 변화와 지반침하를 최소화하기 위한 흙막이 벽체 공법 선정이 매우 중요하다. 이러한 측면에서 CIP 공법의 단점을 보완할 수 있는 SPW 공법은 국내 흙막이 벽체 시공 시 점차 증가하는 추세이다. 이러한 여건을 고려하여 본 연구에서는 SPW 공법의 설계요소와 흙막이 벽체의 구조적 안정요소간 상호 특성에 대하여 연구하였다. 여기서, 흙막이 벽체의 설계요소는 말뚝 간 겹침길이, 말뚝직경, H형강 보강재 규격이며 이에 따른 흙막이 벽체의 구조적 안정요소는 흙막이 벽체의 휨응력, 전단응력, 수평변위, 콘크리트 강도이다. 연구 결과 H형강 보강재의 부재력에 큰 영향을 미치는 설계요소는 말뚝직경과 H형강 보강재 규격이며, 수평변위에 큰 영향을 미치는 설계요소는 말뚝직경과 말뚝 간 겹침길이인 것으로 나타났다. 또한, 콘크리트 강도에 큰 영향을 미치는 설계요소는 말뚝직경과 H형강 보강재 규격인 것으로 나타났다.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권1호
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• pp.10-14
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• 2004

A large area electron beam generator has been developed for industrial applications, for example, waste water cleaning, flue gas treatment, and food pasteurization. The operational principle is based on the emission of secondary electrons from the cathode when ions in the plasma contact the cathode, which are accelerated toward the exit window by the gradient of the electric potential. Conventional electron beam generators require an electron beam scanning mechanism because a small area thermal electron emitter is used. The electron beam of the large area electron beam generator does not need to be scanned over target material because the beam area is considerable. We have fabricated a large area electron beam generator with peak energy of 200keV, and a beam diameter of 200mm. The electron beam current has been investigated as a function of accelerating voltage and distance from the extracting window while its radial distribution in front of the extracting window has been also measured.

• Steel and Composite Structures
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• 제21권4호
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• pp.829-847
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• 2016

This paper investigates the flexural capacity of simply supported steel-concrete composite I beam and box beam under positive bending moment through combined experimental and finite element (FE) modeling. 24 composite beams are included into the experiments and parameters including shear connection degree, transverse reinforcement ratio, section form of girder, diameter of stud and loading way are also considered and investigated. ABAQUS is employed to establish FE models to simulate the behavior of composite beams. The influences of a few key parameters, such as the shear connection degree, stud arrangement, stud diameter, beam length and loading way, on flexural capacity are discussed. In addition, three methods including GB standard, Eurocode 4, and Nie method are also used to estimate the flexural capacity of composite beams and also for comparison with experimental and numerical results. The results indicate that Nie method may provide a better estimation in comparison to other two standards.

• 대한치과의사협회지
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• 제53권12호
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• pp.967-974
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• 2015

Purpose: This study was performed to investigate the characteristics of mandibular incisive canal (MIC) in Korean population. Materials and methods: A total of 97 subjects (60 males and 37 females) who underwent cone-beam computed tomography were included in the study. The anatomic features of MIC was assessed according to gender. Length, diameter and distance to inferior, lingual and buccal border were measured at the origin and the terminal. Also the distribution of MIC at each tooth position was evaluated. Results: Of 97 patients included, 75(77.3%) presented bilateral MIC and 13(13.4%) presented unilateral MIC. Of 194 hamimandibles, MIC was detected in 102(85%) sites in male and 61(82.4%) sites in female. Gender and side showed no statistically significant differences in detectability. The length, diameter and distance to adjacent structures were bigger in male than in female except the distance to lingual border. MIC travelled anteriorly in a slightly downward and lingual direction and usually terminated between the first premolar and the canine. On cross-sectional view, MIC showed individually scattered distribution both buccolingually and superoinferiorly. Conclusion: MIC is well detected with cone-beam computed tomography. Considered that the length and the location of MIC has large variations between individuals, its localization using cone-beam CT is highly recommended before performing surgical procedures such as implant placement and bone harvesting.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.127-133
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• 2003

In this study, a problem formulation and solution for design optimization of laminate composite cylindrical beam section is presented. The objective of this research is to determine the optimal dimension of the laminated composite cylindrical beam sections which has the equivalent flexural rigidities to those of the steel cylindrical beam sections. The analytical model is based on the laminate theory and accounts for the material coupling for arbitrary laminate stacking sequence configuration. The outer diameter and thickness of the beam are design variables. The solutions described are found using a global search algorithm, Genetic Algorithms (GA).

• 한국광학회지
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• 제24권1호
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• pp.23-28
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• 2013

송광광학계의 광원으로 사용되는 광섬유 레이저의 개구수, NA가 0.13~0.22의 범위에 있으면, 이 NA에 관계없이 1 km 전방에서 빔직경이 4.8 m 또는 6.8 m이 되도록 줌렌즈형 광속확대기를 적용한 송광광학계를 설계하였으며, 표적에서의 foot prints를 통하여 빔직경을 확인하였다. $16{\times}16$($100{\mu}m{\times}100{\mu}m$) 픽셀 검출기를 사용하는 수광광학계를 설계하였으며, 검출면의 픽셀 위치에 따른 spot diameter는 모두 $55{\mu}m$ 이하가 됨을 확인하였다. 스캔을 고려하여 송광광학계를 수광부 대물렌즈에 내접하도록 구성하였으며, 이때 송광부에 의하여 가려진 부분은 11%가 되었다.

• 한국구조물진단유지관리공학회 논문집
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• 제25권6호
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• pp.68-75
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• 2021

본 연구에서는 반복하중을 받는 외부 보-기둥 접합부에 정착된 57mm 확대머리철근의 정착성능을 평가하였다. 총 4개의 외부 보-기둥 접합부 실험체를 계획하였으며, 콘크리트 압축강도, 측면피복두께, 횡보강근비 및 파괴유형을 주요 실험 변수로 설정하여 정착성능평가를 수행하였다. 성능평가 결과, 접합부에 정착된 대구경 확대머리철근의 정착성능에 가장 큰 영향을 주는 요소는 측면피복두께 및 횡보강근으로 나타났으며, 외부 보-기둥 접합부에 정착된 57mm 대구경 확대머리철근은 반복하중하에서도 충분한 정착성능이 발현되는 것을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1823-1825
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• 2004

Spherically convergent beam fusion device accelerate ions, which are generated between outer anode and inner grid cathode, toward the spherical center. The collision of opposite direction ions give rise to fusion reactions. Spherically convergent beam fusion device is very simple and compact, therefore the device has a potential that is applied to a portable neutron source. An experimental device consist of a 20cm-diameter spherical mesh-type anode and 7cm-diameter open spherical grid cathode and was maintained at a constant pressure of about 1333 Pa by feeding argon gas.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
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• pp.335-339
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• 2000

In the weaving process, tension control of the warp is important. The variation of the warp tension cause irregularities of the weft density and low quality of the woven fabrics. Due to the fact that the warp tension varies in depending on the difference between take-up velocity and let-off velocity, it is necessary to regulate the velocity of let-off in relation to that of take-up for keeping the warp tension. Futhermore, the diameter of warp beam changes in the weaving process. The changing diameter of warp beam cause changing inertia of warp beam and the velocity of the let-off. It makes the control of such a system more complex. In this paper, we propose a fuzzy controller for the warp tension control. From the computer simulation, it was observed that a developed fuzzy controller has a better performance than that of conventional PI controller.