전파조정기를 이용한 마이크로파 소자용 Calibration

석은영,조현광,서영석,한교용 영남대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.28 No.1

A microwave device measurement tool kit using the TRL method for microwave tuner was developed. Teflon substrate was used for easy manufacturing. An adapter from CDI was used for the junction transition between microstrip and coaxial line. Mask production procedure which have the 3:1 reduction ratio was developed for microstrip transmission line manufacturing. Using these procedure the Cal Kit which can have Thru, Reflect, and Line was manufactured. TRL error correction method can be applied to the Kit. We tested the Cal kit and the error due to the microstrip line could be corrected. It can be applicable to the accurate measurement of microwave transistors.

토오크 측정 장치 개발

김교형,조우석 嶺南大學校 工業技術硏究所 2004 工業技術硏究所論文集 Vol.32 No.2

In this paper torque control system of screw fastener by strain gauge is investigated. Strain gauge sensor applicable to screw fasterner is designed and fabricated. Through the experiments the developed system has showed good screw fasterning capability. Industrial application of the developed system can be expected in terms of productivity increase and quality improvement of assembly lines.

Mo 화학기상증착에 있어서 불순물 농도에 미치는 증착조건의 영향

배상석,서성교,홍은식,김승모,조미정,한혜정,이두성,김세훈,민석홍 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-

The thermal decomposition process of Mo(CO)_6 on chemical vapor deposition was investigated by analyzing the effects of deposition temperature, pressure, and reaction gas on the phase change of deposited films. Mo_2C was deposited at or below 350℃ due to the incompleteness of thermal decomposition of Mo(CO)_6, but Mo films was successfully deposited at 400℃ or higher temperatures. The variation of deposition pressure did not change the dependence of decomposition process on deposition temperature. The activation energy of surface reaction was 5.8 ㎉/mole.

TiN Ion-Plating이 교정용 브라켓의 접착강도에 미치는 영향

김석용,권오원,김교한 대한치과교정학회 1997 대한치과교정학회지 Vol.27 No.1

TiN ion-plating이 교정용 브라켓의 접착강도에 미치는 영향을 알아보기 위하여 세 종류의 서로 다른 기저면형태를 가지는 스테인레스 스틸제의 브라켓을 선택하고, TiN ion-plating 된 브라켓과 ion-plating 되지 않은 브라켓을 치아에 접착시켰을 때 초기 및 장기접착강도, 접착계면의 주사전자현미경 관찰, 파단면의 주사전자현미경 관찰을 비교 분석하여 다음과 같은 결론을 얻었다. · TiN ion-plating을 하지 않은 경우 24시간 후의 접착강도는 Micro-Loc형이 5.89±1.77MPa, Foil Mesh형이 4.27±1.12MPa, Undercut형이 2.64±0.58MPa로 Micro-Loc형이 가장 높았고, 그 다음이 Foil Mesh형 그리고 Undercut형의 순으로 나타났다(P<0.05). · TiN ion-plating시 24시간 후의 접착강도는 Micro-Loc형이 6.26±1.51 MPa, Foil Mesh형이 7.45±2.01MPa, Undercut형이 2.93±0.84MPa로 ion-plating 하지 않은 경우와 달리 Foil Mesh형이 Micro-Loc형보다 오히려 높게 나타났고, Undercut형이 역시 가장 낮은 접착강도를 나타내었다(P<0.05). Ion-plating 유무에 따른 24시간 후의 접착강도는 3가지형 모두에서 ion-plating시 증가하였으나 Foil Mesh형에서만 유의한 증가가 있었다(P<0.001). · 장기침적시 ion-plating의 유무에 관계없이 전반적으로 초기(1일)접착강도보다 증가하였으며 접착력의 안정성을 나타내었다. · 접착계면의 주사전자현미경 관찰 결과 브라켓 기저면의 형태나 ion-plating 유무에 관계 없이 레진이 브라켓 기저면으로 잘 퍼져 들어가 브라켓과 치아와의 사이에 견고한 접착면을 나타내었고, 장기침적의 경우도 같은 양상을 나타내었다. · 파단면의 주사전자현미경 관찰에서는 다양한 파괴양상이 나타났다. This study was conducted to see the effect of TiN ion-plating on the bond strength of orthodontic bracket. Three stainless-steel brackets with different base types were chosen; when TiN ion-plated brackets and non ion-plated brackets were bonded to the teeth, initial and long-term bond strength were measures. The observations of bonding surface and failure sites through the scanning electron microscope were analysed and compared. The summary of this study was as follows: · When TiN ion-plating was not applied, the Micro-Loc type was the highest in bond strength after 24 hours as 5.89±1.77MPa, followed by 4.27±1.12MPa for Foil Mesh type and 2.64±0.58MPa for Undercut type(P<0.05). ·Under TiN ion-plating, the bond strength after 24 hours showed: Micro-Loc type 6.26±1.51MPa, Foil Mesh type 7.46±2.01MPa, Undercut type 2.93±0.84MPa. Unlike in the case of non ion-plating, Foil Mesh type showed a higher strength than Micro-Loc type, with Undercut type still showing the lowest bond strength(P<0.05). The bond strength, after 24 hours, increased in case of ion-plated in all 3 types, but a significant increase was shown only in Foil Mesh type(P<0.001). · Under a long-term immersion, regardless of ion or non ion-plating, bond strength in general increased over the initial bond strength(one day), with more stability. · Through scanning electron microscopic observation of bonding surface, it was found that, regardless of the bracket base type or the application of ion-plating, the resin was thoroughly spreaded into bracket base to form a solid bonding surface between the bracket and the tooth. This was also true in case of a long-term immersion. · The scanning electron microscopic observation of failure sites revealed diverse failure patterns.

건설VE에서의 준비단계와 분석단계 연계방안에 관한 연구

손석구,현창택,구교진 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1

Value Engineering(VE) is in force for strengthening the competitiveness in internal construction industry. But, although there are systematic, technical efforts, VE is recognized only a method of cost saving in internal construction industry. Each phase of VE has not been connected organically and cut. It has focused only cost saving in target selection phase and function definition has been performed by original functions that target has. This study suggests the connection process between a target selection of preparation phase and a function definition of analysis phase, and reflects needs of clients and users and project characters in the target selection. This study suggests a method of an effective function definition

황색종 원료잎담배 숙성과정중 지습에 따른 품질변화

송교철,석영선,이학수 충북대학교 엽연초연구소 2001 煙草硏究 Vol.18 No.-

This study was carried out to investigate the influence of the dampness of concrete floor in storeroom on the quality of packed flue-cured leaf tobacco with corrugated causes for aging. The results were summarized as follows. The moisture and relative humidity conditions at the 15cm height from the concrete floor were 2.2℃ lower and 16% RH higher than those at the 300 cm height in the storeroom. Due to loading position, no significant changes in moisture content of leaf tobacco in the third layer was found. However, in the first layer, 2.4% of increase in moisture content was found. In the case of the layer, the circumference of corrugated casses was increased more largely than in the middle. During aging, the nicotine and total sugar content and pH value in leaf tobacco were decreased. Due to loading position, the pH, nicotine and total sugar content of leaf tobacco in the first layer were decreased significantly than those in the third layer. After aging, the degree of the lightness(L) and the yellowness(b) of leaf tobacco in the first layer were dropped by 3.2 and 2.5, respectively. However, the degree of the redness(a) was Increased by 0.63. Mold was occured in the leaf tobacco at the low part of the first layer.

트랙터의 자율주행 제어에 관한 연구

채창현,오영석,금교운,최한고,채석,김학성,이상재 金烏工科大學校 産業技術開發硏究院 1999 産業技術開發硏究 Vol.15 No.-

Recently, the research on the automatic mobile tractors has become active, especially steering control system. It is required that the steering system is able to robust to external loads, and to have large torque in a small area. The steering system consists of hydraulic components, mechanical parts, a steering actuator replacing the steering wheel, and a control device. In this paper, we proposed the steering fuzzy-control algorithm for automated tractor and its effectiveness has been shown by field test on the straight road, s-type road, and crank-type road.

암석 슬러지를 이용한 건자재 개발

이필호,이구연,전철수,연규석,이윤수,인교진 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

본 연구는 1993년부터 춘천시 신동면 형돌리 산 62번지 내에서 흑운모 화강암 및 편마암 암석을 원자재로 사용하여 건설기초재료인 쇄설골재 및 인공모래를 생산하는 업체로부터 제품 생산 후 발생하는 토양 스러치 케익이 연간 약 10만 입방정도 발생한다는 사실에 기초하여 석산에서 채취된 페잔토(석분)의 화학적, 물리적, 역학적 특성을 조사하여 석분의 이용 가능성을 확인하기 위한 실험으로 단위 시멘트량을 400kg, 잔골재율을 45% 그리고 물-시멘트비를 65%로 고정하고 잔골재 중 석분을ㄹ 0%, 10%, 20%, 30%, 40%, 50% 및 60%로 치환하여 제조된 콘크리트의 기초적 성질을ㄹ 시험하였다. 그 결과 석분의 치환율이 높을 수록 공기량은 증가하고 슬럼프값이 감소하였는데 이는 미세한 입자인 석분을 잔골재의 일부로 치환함으로써 비표면적이 증가하였기 때문인 것으로 사료된다. 압축강도와 휨강도는 모두 석분의 치환율이 증가할수록 압축강도와 휨강도는 다소 감소하는 경향을 나타냈으나 큰 성능차이는 보이지 않는 다는 것을 알 수 있었다. 이상의 실험을 통해 석분을 시멘트 콘크리트에 사용했을 경우 약간의 성능저하는 있지만 잔골재로의 활용이 가능하다는 것을 알 수 있었다. 그러므로 앞으로 건조수축, 균열, 크리이프 특성 및 내구성에 과한 연구가 더욱 심도있게 이루어져야 폐자원인 석분의 이용이 가능하리라 판단된다. This study aims to make cement concrete using crushed stone fines which are produced at Chuncheon city, Hyuldongri and find it's applications. According to the experimental results, when ratio of crushed stone fines was increased, air contents were increased and slump values were decreased. Also, the compressive strength and flexural strength were decreased when ration of crushed stone fines was increased. Although these strengths are decreased, the crushed stone fines can be used to construction materials because the decreased amounts are not so much.

Comparison Of Spatial Interpolation Methods For Estimation Of Air Temperature

Seok-Cheol Kim,Yong-Seok Kim,Myung-Pyo Jung,Kyo-Moon Shim 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Fault-Tolerant Strategy using Neutral-Shift Method for Cascaded Multilevel Inverters Based on Level-Shifted PWM

Seok-Min Kim,June-Seok Lee,Kyo-Beum Lee 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Most proposed methods for a fault-tolerant operation in many of studies are based on a phase-shifted PWM (PS-PWM) method. However these methods are not applied directly to multilevel inverter systems using a levelshifted PWM (LS-PWM). This paper focuses on faulttolerant operation for a cascaded multilevel inverter based on LS-PWM. During the occurrence of a single-inverter-cell fault, reconfiguration of the carrier bands scheme is implemented and modulation assignment of inverter cells is modified in this proposed fault-tolerant operation. It is possible to generate balanced three-phase line-to-line voltages and line currents with the proposed strategy when a device failure occurs in cascaded multilevel inverters using LS-PWM. The feasibility of the proposed method is proved by simulation results.