• 한국전기전자재료학회논문지
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• 제17권4호
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• pp.448-452
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• 2004

The micromachined variable optical attenuator(VOA) was presented in the paper. The VOA has two single mode fiber(SMF) aligned with free space and symmetric parallel plate actuator with microshutter, which can control a amount of light by driving the actuator. In the paper, analysis on driving performances of the VOA was performed and can be reduced threshold voltage through the decreasing displacement actuating range. This paper presents a VOA that is fabricated using bosch deep silicon etching process with silicon on insulator(SOD wafer. The VOA consists of driving electrode, ground electrode, actuating microshutter, and mechanical stopper. In this VOA, actuating shutter is driven by electrostatic force and the threshold voltage is close to 28V, 46V come along with the spring width of 5${\mu}{\textrm}{m}$, 7${\mu}{\textrm}{m}$ respectively. Attenuation range is measured from 2.4㏈ to 16.7㏈.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2260-2262
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• 2000

In this paper, micromirror which can rotate 45 degree is designed, analyzed and fabricated. The micromirror is parallel to the substrate initially. When external magnetic field is applied, a micromirror can rotate to align its easy axis to the field. The size of micromirror array is $10{\times}10$. The mirror plate and spring is made of aluminium, and nickel is used as soft magnetic material. To obtain 45 degree angular deflection, dimension ratio between stopper length and thickness of sacrificial layer is properly selected. By using electrostatic force, individual actuation is possible.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.626-633
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• 2000

An air spring which is a part of the railroad vehicle suspension system is used to reduce and absorb the vibration and the noise. Main components of the air spying are a cord reinforced rubber bellows, a upper plate, a lower plate and a stopper rubber spring. The characteristics of the air spring which are the load capacity, the vertical and the horizontal stiffness are depended on the configuration of rubber bellows, the angle of cord and the mechanical properties of cord. The computer simulation using commercial finite element analysis codes are executed to predict and evaluate the load capacity and the stiffness. The appropriate shape and cord angle of the air suing are selected to adjust the required performance of the air spring. Several samples of the air spring are manufectured and experimented. It is shown that the results by computer simulation are in close agreement with the test results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1929-1931
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• 2001

An adaptive fuzzy logic controller to regulate molten steel level in the strip casting process is presented, where parameters of fuzzy controllers are adapted stably by using Lyapunov-stability theory and a switching controller is used together to deal with the approximation error of fuzzy logic system. The level error is proven to converge to zero asymptotically. In the simulation, the clogging/unclogging of a stopper nozzle is considered and overcome by the proposed controller. Robustness to uncertainty is shown to be superior to conventional PI controller.

• Journal of Welding and Joining
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• 제23권6호
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• pp.55-60
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• 2005

In part 1. optimal process parameters such as thickness of stopper and welding time are achieved to produce high strength ISB(Inner Structured and Bonded) panels. Developed process is different from the usual resistance welding process in the number of points welded at a time. In part 2, Numerical modeling for this new process is proposed and the variation of contact area with respect to the gap of electrodes is studied through FE analyses, Besides, it is tried to figure out the welding nugget formation and proper distance between welding points. FE analytic results show that inner structures are melted more than skin plate, and current distribution between points to be welded can be controlled by distance welding points. Comparison of some FE analytic results with corresponding experimental results could confirm the validity of the proposed numerical modeling.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.188-191
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• 2005

In this paper, a design optimization technique is presented for determining the stiffness and the damping coefficient of the shock absorber that is used in the Gullwing door system of passenger car. The contact force between the shock absorber and stopper link, when the door is opened, is set up as objective function, and the stiffness and the damping coefficient are set up as design variables. ADAMS optimization module (SQP method) is applied in the design optimization process. This study shows that the stiffness and the damping coefficient of the shock absorber can be effectively determined in initial design stage of the Gullwing door.

• 정보저장시스템학회논문집
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• 제9권2호
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• pp.56-61
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• 2013

The recent increased use of mobile phone has resulted in a technical focusing on reliability issues related to drop performance. Since mobile phone may be dropped several times during their use, it is required to survive common drop accidents. The plastic injection parts such as base stopper and carrier in the encoder type actuator can be broken easily in the actual reliability test of 1.5m free drop. So, we analyzed the shock resistance characteristics of auto focus actuator with variables in the material properties using finite element method. By applying the new resin materials, we can decrease the breakage of plastic injection parts and improve the reliability of mobile phone.

• 대한토목학회논문집
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• 제33권3호
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• pp.1095-1104
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• 2013

2011년 6월 기준으로 국내 자동차등록대수는 1,826만 대에 육박할 정도로 비약적인 증가를 보이고 있다. 최근 급속히 증가하고 있는 대형 승용차 및 RV차량이 현재 설치된 주차장에 주차할 경우 차량훼손, 민원 발생 등 주차장 이용자의 통행불편을 겪고 있는 실정이다. 특히, 주자장에 무분별하게 설치된 카스토퍼는 주차사고 유발 및 주차문제를 더욱 더 증가시킴과 동시에 경제적 손실을 초래하고 있다. 이에 본 연구에서는 현실에 적합한 주차단위구획 및 카스토퍼 설치위치 규정의 재정비가 필요하다고 판단되어, 국내 외 차종별 구성비, 차종별 차폭 및 길이에 대한 현장조사와 카스토퍼가 설치된 주차단위구획 및 차종별 구성비 변화 사례 등을 선행 검토하였다. 또한, 차종별 제원 및 카스토퍼 설치위치를 고려하여 주차단위구획을 산정하였다. 그 결과, 대형 승용차의 여유폭이 기존보다 18 ~ 21mm 정도 감소한 것으로 나타났다. 이는 차량의 앞내민길이가 주차단위구획을 벗어나지 않으므로 주차장 사고를 감소시킬 수 있을 것으로 판단된다. 최종적으로 운전자 측면에서 편의성 및 안전성이 향상된 주차계획 개선안을 제시하였다. 향후 본 연구를 통해 개선된 주차계획을 적용할 경우 주차장의 구조 및 설치기준 정립은 물론 더 나아가 주차장 관련사업의 비용/효율성을 극대화할 수 있을 것으로 기대된다.

• 한국정보통신학회논문지
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• 제13권7호
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• pp.1393-1398
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• 2009

본 연구는 LCD용 비정질 실리콘박막트랜지스터의 제조공정중 가장 중요한 식각 공정에서 각 박막의 특성에 맞는 습식 및 건식식각공정을 개발하여 소자의 특성을 안정시키고자 한다. 본 연구의 수소화 된 비정질 실리콘 박막 트랜지스터는 Inverted Staggered 형태로 게이트 전극이 하부에 있다. 실험 방법은 게이트전극, 절연층, 전도층, 에치스토퍼 및 포토레지스터층을 연속 증착한다. 스토퍼층을 게이트 전극의 패턴으로 남기고, 그 위에 n+a-Si:H 층 및 NPR(Negative Photo Resister)을 형성시킨다. 상부 게이트 전극과 반대의 패턴으로 NPR층을 패터닝하여 그것을 마스크로 상부 n+a-Si:H 층을 식각하고, 남아있는 NPR층을 제거 한다. 그 위 에 Cr층을 증착한 후 패터닝 하여 소오스-드레인 전극을 위한 Cr층을 형성시켜 박막 트랜지스터를 제조한다. 여기서 각 박막의 패터닝은 식각 공정으로 각단위 박막의 특성에 맞는 건식 및 습식식각 공정이 필요하다. 제조한 박막 트랜지스터에서 가장 흔히 발생되는 문제는 주로 식각 공정시 over 및 under etching 이며, 정확한 식각을 위하여 각 박막에 맞는 식각공정을 개발하여 소자의 최적 특성을 제공하고자한다. 이와 같이 공정에 보다 엄격한 기준의 건식 및 습식식각 공정 그리고 세척 등의 처리공정을 정밀하게 실시하여 소자의 특성을 확실히 개선 할 수 있었다.

• 한국군사과학기술학회지
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• 제20권1호
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• pp.55-62
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• 2017

For evaluating a large caliber ammunition tests, indoor ballistic test range is required to reduce the noise and fragments occurring during the test. To ensure the reliability of the indoor ballistics test range design, we carried out the analysis of the indoor test range using the AUTODYNE hydrodynamic code before its construction. The 120 mm tank ammunition is adopted as a reference model and we analysed the characteristics of the pressure distribution at fire area, the structure design at impact area, the over-pressure applied to the tunnel, and the sabot stopper design. The results of the analysis were applied to the design of the indoor ballistic test range.