• 대한기계학회논문집A
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• 제32권3호
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• pp.209-216
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• 2008

The application of focused ion beam (FIB) depends on the optimal interaction of the operation parameters between operating parameters which control beam and samples on the stage during the FIB deposition process. This deposition process was investigated systematically in C precursor gas. Under the fine beam conditions (30kV, 40nm beam size, etc), the effect of considered process parameters - dwell time, beam overlap, incident beam angle to tilted surface, minimum frame time and pattern size were investigated from deposition results by the design of experiment. For the process analysis, influence of the parameters on FIB-CVD process was examined with respect to dimensions and constructed shapes of single and multi- patterns. Throughout the single patterning process, optimal conditions were selected. Multi-patterning deposition were presented to show the effect of on-stage parameters. The analysis have provided the sequent beam scan method and the aspect-ratio had the most significant influence for the multi-patterning deposition in the FIB processing. The bitmapped scan method was more efficient than the one-by-one scan type method for obtaining high aspect-ratio (Width/Height > 1) patterns.

• Geomechanics and Engineering
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• 제28권3호
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• pp.209-224
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• 2022

In this study, the numerical analysis model of π-beam explosion is established to compare and analyze the failure modes of the π-beam under the action of explosive loads, thus verifying the accuracy of the numerical model. Then, based on the numerical analysis of different protection forms of π beams under explosive loads, the peak pressure of π beam under different protection conditions, the law of structural energy consumption, the damage pattern of the π beam after protection, and the protection efficiency of different protective layers was studied. The testing results indicate that the pressure peak of π beam is relatively small under the combined protection of steel plate and aluminum foam, and the peak value of pressure decays quickly along the beam longitudinal. Besides, as the longitudinal distance increases, the pressure peak attenuates most heavily on the roof's explosion-facing surface. Meanwhile, the combined protective layer has a strong energy consumption capacity, the energy consumed accounts for 90% of the three parts of the π beam (concrete, steel, and protective layer). The damaged area of π beam is relatively small under the combined protection of steel plate and aluminum foam. We also calculate the protection efficiency of π beams under different protection conditions using the maximum spalling area of concrete. The results show that the protective efficiency of the combined protective layer is 45%, demonstrating a relatively good protective ability.

• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.327-333
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• 2015

This paper reports the fabrication of various micro-lensed single-mode optical fibers through the use of an enhanced peak power $CO_2$ laser beam. The end faces of the optical fibers are exposed to the $CO_2$ laser beam to form convex, concave, and conical shape optical fiber tips. Peak power of the $CO_2$ laser beam was varied from 0.8 W to 1.5 W depending on the shape of the optical fiber tip. We also discover the dependence of the angle of the optical fiber tip on the rotation angle and the number of $CO_2$ laser irradiations. The angle shows an increasing trend with both these parameters. We achieve a wide range of lenticular fibers with end face angle varying from $4.47^{\circ}$ to $8.13^{\circ}$. Furthermore, we investigate the emission pattern of light from the developed micro-lensed fibers. The proposed $CO_2$ laser based optical fiber reshaping technique shows great consistency, and thus is suitable for commercial applications.

• 한국자기학회지
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• 제17권4호
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• pp.178-181
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• 2007

반도체의 고 집적회로를 형성하기 위하여 주로 이용하고 있는 광 리소그래피 기술을 대신하여 사용할 수 있는 차세대 리소그래피 기술로 전자빔 리소그래피 기술에 대한 연구가 진행되고 있다. 본 연구에서는 초소형 전자칼럼을 이용하여 전자빔 에너지와 조사농도에 따른 pattern 두께의 의존성을 조사하였으며 두께가 100nm인 $SiO_2$ 박막의 patterning을 통하여 $SiO_2$ 박막에 대한 저 에너지 전자빔 리소그래피 공정의 가능성을 입증하였다.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4405-4410
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• 2015

두 개의 1차원 주기 패턴을 수직으로 중첩시켜 상하층 패턴으로부터 이축 변위 정보를 각각 디코딩할 수 있는 방법을 제안한다. 투명한 상층 패턴 판별은 굴절률차에 기인한 레이저 빔의 디플렉션 검출을 통해 이뤄지고 하층 패턴 판별은 수광 전압 차의 검출를 통해 이뤄진다. 빌드 업 필름 재질의 상층 패턴은 UV 레이저 가공에 의해 미세가공되고 그리고 알루미늄 하층 패턴은 초정밀 머시닝에 의한 트렌치 가공과 불투명 소재 증착 그리고 폴리싱 과정을 통해 제작된다. 10마이크로미터 간격으로 제작된 샘플 패턴과 이를 인코딩할 수 있는 전용 광학계에 의한 변위 측정 방법은 대면적 스테이지에 장착되어 레이저 간섭계를 이용한 측정데이터와 비교하여 검증된다.

• Journal of electromagnetic engineering and science
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• 제18권3호
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• pp.175-181
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• 2018

The array patterns of a patch array antenna were calculated using an active element pattern (AEP) method that considers ground edge effects. The classical equivalent radiation model of the patch antenna, which is characterized by two radiating slots, was adopted, and the AEPs that include mutual coupling were precisely calculated using full-wave simulated S-parameters. To improve the accuracy of the calculation, the edge diffraction of a ground plane was incorporated into AEP using the uniform geometrical theory of diffraction. The array patterns were then calculated on the basis of the computed AEPs. The array patterns obtained through the conventional AEP approach and the AEP method that takes ground edge effects into account were compared with the findings derived through full-wave simulations conducted using a High Frequency Structure Simulator (HFSS) and FEKO software. Results showed that the array patterns calculated using the proposed AEP method are more accurate than those derived using the conventional AEP technique, especially under a small number of array elements or under increased steering angles.

• 한국정밀공학회지
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• 제29권10호
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• pp.1144-1148
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• 2012

Process conditions for generating nano patterns handle different process according to the pattern characteristics, and different process data according to patterns in questions. To efficiently find optimal process conditions for generating nano patterns, process data by experiment is needed consideration of the pattern characteristics concerning the equipment. In particular, coating methods of a cylindrical mold differ from it of a flat plate because of viscosity of coating materials. Also the coating thickness affects nano process and pattern line width. So coating method of coating thickness for cylindrical mold is very important on nano pattern generating. In this study, a method is proposed for coating Photo Resist through the spray in order to coat cylindrical mold and measuring the thickness of coating using measuring tip considering the size of cylindrical mold because there is no method in the existing SEM. The proposed method is applied to a real printed electronics system to verify its accuracy and efficiency.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.24-29
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• 2005

Fm (Focused ion beam) system is one of the most important equipments for the nano-scale machining. Various researches have been performed, since it can etch the material and deposit 3-D structure with high-aspect-ratio in the nanometer scale. In spite of those researches, the definite method for the reliability of FIB system has not been reported. In this paper, we proposed the reliability assessment method through nano-pattern fabrication. In the fabricated nano-pattern, the characteristics of FIB system are included. Using this effect, we tried to assess the FIB reliability. First, we suggested reliability assessment items and nano-patterns. And, to know the suitableness of the proposed method, we fabricated several nano-patterns using Nova200(FEI Company) and SMI2050(SEIKO) which are FIB apparatuses. The fabricated nano-patterns are measured with SEM (Scanning Electron Microscope) and compared with designed dimensions. And the compared results showed that the proposed method is suitable for the assessment of FIB system reliability.

• 한국전자파학회논문지
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• 제22권12호
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• pp.1155-1164
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• 2011

본 논문에서는 국내 최초로 개발되는 함상용 중거리 레이더에 사용되는 능동 위상 배열 안테나의 송신 빔 특성을 근접 전계 시험으로 측정하는 방안에 대하여 제시하였다. 측정하고자 하는 능동 위상 배열 안테나는 고출력 송신 빔을 펄스 형태로 방사하기 때문에 저출력의 연속적인 파형을 사용하는 일반적인 근접 전계 시험 시설에서는 측정하기 어렵다. 그래서 본 논문에서는 고출력 송신 시에도 견딜 수 있도록 설계된 근접 전계 시험 시설과 펄스 모드 측정을 지원하는 Agilent사의 PNA-X 네트웍 분석기를 이용한 근접 전계 시험으로 펄스 형태의 고출력 송신 빔을 방사하는 능동 위상 배열 안테나를 측정하는 방안에 대하여 제시하였고, 실제 개발된 능동 위상 배열 안테나의 고출력 송신 빔 패턴을 근접 전계 시험으로 측정하였다. 또한, 능동 위상 배열 안테나의 송신 특성인 EIRP(Effective Isotropic Radiated Power)를 측정하였고, 수학적인 계산을 통해 예측한 EIRP 값과 비교한 결과 0.1 dB의 오차 내에서 동일함을 확인하였다.

• 한국강구조학회 논문집
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• 제16권2호통권69호
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• pp.225-233
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• 2004

일반적인 합성보는 콘크리트 슬래브와 H형강 철골보 사이에 작용하는 수평전단력을 쉬어 코넥터로 긴결하여 휨 내력 및 강성을 증가시킨 구조이다. 본 연구에서 제안한 TSC 구조는 H형강 대신 U형 철골을 사용하고 그 속에 콘크리트를 채운 새로운 형태의 합성보 시스템으로 실험을 통하여 구조특성을 평가 분석 하였다. 또한 실험결과를 통해 T형 합성보(이하 TSC 보라 칭함)의 구조설계 및 시공에 필요한 기초 자료를 제시하고자 한다.