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개인-직무 적합성이 직무만족도 및 경력몰입에 미치는 영향
안기복(Ahn, Gi-Bok),나용근(Na, Yong-Geun),김영중(Kim, Young-Joong) 한국외식경영학회 2021 외식경영연구 Vol.24 No.5
본 연구는 조리 종사원들의 개인-직무 적합성의 하위차원인 수요-능력 적합성과 욕구-공급 적합성이 직무만족도 및 경력몰입에 미치는 영향 관계를 파악하고 추가적으로 리더-구성원 교환관계의 조절 효과를 실증 분석하였다. 실증연구를 위해 확보된 238개의 표본을 바탕으로 연구모형의 신뢰성, 적합성 등을 검토하였고, 구조방정식을 사용하여 가설을 검증하였다. 실증분석결과 수요-능력 적합성과 욕구-공급 적합성은 직무만족도에 유의한 영향을 미치고 있었으며 직무만족도는 경력몰입에 정(+)의 영향을 주는 것으로 조사되었다. 더불어 리더-구성원 교환관계의 조절 효과는 일부 존재하는 것으로 나타났다. 이러한 결과를 통해 조리 종사원들의 수요-능력 적합성과 욕구-공급 적합성은 직무만족도를 높여 경력몰입을 증가시킨다는 것을 확인하였다. The purposes of this study was to analyze the person-job fit on job satisfaction and career commitment. The hypothesized relationships in the model were simultaneously tested using structural equation model(SEM). Developed questionnaires were collected from 250 employees working in nine foodservice industry located at Daegu and Gyungju area. A total of 238 survey responses were used for statistical analysis, excluding 12 insincere respondents. Results were as followed. First, it was found that demand-ability fit, needs-supplies fit had a significant positive(+) effect on job satisfaction. Second it was investigated that job satisfaction had a significant positive(+) effect on career commitment. These founding provide several practical suggestions for managing employees to foodservice industry managers. The limitations of the current study and recommendations for further research were explained as well.
김기복(Ki-Bok Kim),안봉영(Bongyoung Ahn),박해원(Haewon Park),김영주(Young-ju Kim),이승석(Seung-Seok Lee) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.8
In this study, the capacitive micromachined ultrasonic transducer (cMUT) was developed. Theoretical analysis and finite element analysis of the behavior of membrane (such as resonance frequency, membrane deflection, collapse deflection and collapse voltage) of the cMUT were performed. The design parameters of the cMUT were estimated and are the dimension and thickness of membrane, thickness of sacrificial layer, thickness and size of electrode, size of active element and so on. With the micro-fabrication process, the cMUT was fabricated on the silicon wafer. To measure the membrane displacement of cMUT, the Michelson phase modulation fiber interferometer was constructed. The measured membrane displacement was good agreed with the result of finite element analysis. To estimate the ultrasonic wave generated by the cMUT, the ultrasonic transceiver system was constructed. The developed cMUT shows a good performance and hence will be widely used to the filed of non-contact ultrasonic application.
안봉영(Bongyoung Ahn),조승현(Seung Hyun Cho),김영주(Young Joo Kim),김기복(Ki-Bok Kim) 한국비파괴검사학회 2010 한국비파괴검사학회지 Vol.30 No.4
EMAT는 비접촉식 탐촉자인 동시에 모드 선택성이 우수하여 다양한 분야에 적용되고 있으나 근본적으로 에너지 전환효율이 낮아 신호 대 잡음비의 증가에 한계를 보인다. EMAT에 위상배열 기술을 접목하면 초음파의 집속 효과를 얻을 수 있으므로 낮은 전환효율의 문제를 극복하기 위한 하나의 해결방안이 될 수 있을 것으로 판단한다. 본 연구에서는 위상배열 EMAT에 대한 기초연구로 3~4개의 코일로 구성되는 표면파 및 수직횡파 발생용 위상배열 EMAT를 제작하고 각 요소코일에 공급하는 펄스의 지연으로부터 위상배열의 효과를 확인하고 방향특성을 측정하였다. 또한 시험편의 표면에 0.5 mm 깊이의 표면결함과 시험편 내부에 직경 0.5 mm의 측면 드릴 홀을 가공하여 제작된 위상배열 EMAT로 결함 신호를 검출하였으며, 이로부터 제작된 EMAT의 성능을 평가하였다. EMAT has been applied in various fields for flaw detection and material characterization because it has noncontact property in wave generation and a good mode selectivity. Unfortunately, however, EMAT shows low signal to noise ratio relative to commercial contact transducer because of low energy conversion efficiency. If the phase matching through the control of time delay between each coil consisting of the array EMAT is accomplished, it is expected that it will be a solution for the improvement of low signal to noise ratio. In this experiment, the phased array EMATs which consists of 3 or 4 meander coils and one big magnet were fabricated for surface and vertical shear wave generation. Effect of phased delay control on signal directivity and amplitude enhancement was verified. A slit with the depth of 0.5 mm and a side-drill hole of 0.5 mm diameter were clearly detected by fabricated phased array EMATs, respectively.
미세채널 내 정재초음파 장 형성 및 미세입자 거동 관찰
조승현(Seung Hyun Cho),서대철(Dae-Cheol Seo),안봉영(Bongyoung Ahn),김기복(Ki-Bok Kim),김용일(Yong-Il Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Using ultrasonic standing waves, the position of micro particles submerged or flowing in fluid can be manipulated. Due to the acoustic radiation force of ultra sounds, particles are forced to move to pressure nodes or antinodes of standing wave field. In this work, ultrasonic standing wave field was generated in a micro water channel of a few millimeter width and the behavior of the submerged particles was observed. The standing wave field generation system was established using an immersible ultrasonic transducer. The system is valid in a frequency range between 2.0 ㎒ and 2.5 ㎒. Particles in consideration were SiC powder of a few micrometer diameters. It was observed that the particle in water moves to pressure nodal lines in the standing field. The effect of the channel thickness and operating frequency on the particle behavior was also investigated.
조승현(Cho, Seung-Hyun),박재하(Park, Jae-Ha),안봉영(Ahn, Bong-Young),김기복(Kim, Ki-Bok) 한국소음진동공학회 2010 한국소음진동공학회 논문집 Vol.20 No.1
Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.
미세가동 정전용량형 초음파 탐촉자 개발(Ⅱ) : 미세공정기술 분석 Analysis of Microfabrication Process
김기복,안봉영,박해원,김영주,김국진,이승석 한국비파괴검사학회 2004 한국비파괴검사학회지 Vol.24 No.6
본 연구는 cMUT 제작을 위한 미세공정기술을 개발하기 위하여 수행되었다. 이를 위하여 외국의 관련 제조공정 연구결과들을 분석하였다. cMUT 제작의 주요 공정인 미소 진동 박막 형성, 희생층 형성, 식각 공정에 대한 실험을 수행하여 적절한 공정조건을 찾고자 하였다. 각 제작 공정조건들을 변화시켜 가면서 증착된 실리콘 질화막의 두께, 균일도, 잔류응력을 측정하였다. 희생층으로서 실리콘 산화막의 공정조건을 변화시켜 가면서 산화막의 성장률을 분석하였다. 마지막으로 희생층 식각을 위한 최적 식각공정을 얻기 위한 실험을 수행하였다. 본 연구에서 얻어진 주요 미세공정 조건은 추후 cMUT 제작에 적용될 예정이다. The main goal of this study was to develop a micro-fabrication process for the capacitive micromachined ultrasonic transducer (cMUT). In order to achieve this goal, the former research results of the micro-electro-mechanical system (MEMS) process for the cMUT were analyzed. The membrane deposition, sacrificial layer deposition and etching were found to be a main process of fabricating the cMUT. The optimal conditions for those microfabrication were determined by the experiment. The thickness, uniformity, and residual stress of the Si₃N₃ deposition which forms the membrane of the cMUT were characterized after growing the Si₃N₃ on Si-wafer under various process conditions. As a sacrificial layer, the growth rate of the SiO₂ deposition was analyzed under several process conditions. The optimal etching conditions of the sacrificial layer were analyzed. The microfabrication process developed in this study will be used to fabricate the cMUT.