등온화용기를 이용한 공기압 기기 누설유량계측에 관한 연구

지상원 부경대학교 2009 국내박사

Leak detection technology is a challenging research until nowadays, because it has wide and various applications in industry, such as gas pipeline leak detection, vacuum industry and mechanical component leak detection, etc. The growing needs for leak-tight products, such as automotive components, pneumatic components, vacuum components, have made the demand on high performance leak detectors for increase of a quality control. Numerous leak detection methods have been developed. Radio isotope, helium sniffing, ultrasonic, thermal conductivity, halogen sniffing, bubble immersion, flow measurement and differential pressure measurement are well-known leak detection methods that have been used in the leak detector manufacturing industry. Also, pneumatic component reliability test based on ISO requires air leakage measurement. Pneumatic component has many seal parts and the leakage shall be measured before, during, and after endurance test, and the leakage should be smaller than the specified value. The existing measurement method needs complex operation and the calibration of the leak detector. And conventional methods have to separate the testing pneumatic component from endurance test device, which causes the change of contact condition of seal in the pneumatic component. Therefore, it is hard to evaluate the air leakage during endurance test, and do not guarantee the reliability analysis results of the conventional measurement method. In this paper, a new method for air leakage measurement using an isothermal chamber is proposed, which does not requires calibration or temperature compensation, and can measure air leakage accurately with quite simple operations. As a result, reliability of air leakage measurement can be improved because the proposed method does not have to separate the testing components from the endurance test device for the air leakage measurement. The effectiveness of the proposed method is proved by simulation and experimental results. ㅁ본 논문에서는 용기내부의 온도변화를 등온(1[K] 미만의 온도변화)으로 유지시키는 등온화용기를 이용하여 용기내부의 압력변화를 유량으로 환산함으로써 공기압 기기의 누설유량을 계측할 수 있는 방법을 제안하였다. 제안한 누설유량계측법은 등온화용기와 압력센서를 추가하는 것만으로 실현이 가능하므로 공기압 기기가 설치되어 있는 회로에서 누설유량계측을 위해 공기압 기기를 분리하지 않아도 누설유량계측이 가능하다. 따라서 상기의 계측법은 기존방법에 비해 누설계측을 위한 비용과 시간을 절약할 수 있으며, 비교적 넓은 범위의 계측이 요구되는 공기압 기기의 누설유량계측에 적합하다. 본 논문에서 제안한 누설계측법을 적용하여 실제 공기압 기기의 누설유량계측 실험을 수행하였고, 실험을 통하여 제안한 방법의 유효성 및 타당성을 검토하였다. 본 논문의 연구결과를 각 장별로 간략히 정리하면 다음과 같다. 2장에서는 종래의 누설유량계측법에서와 같이 시험체적 내부 공기의 상태변화를 등온변화로 가정하게 될 경우 계측된 누설유량의 오차가 발생할 수 있음을 설명하였고 시험체적 내부 공기의 온도변화를 고려하여야 누설유량 계측의 정확성을 향상시킬 수 있는 것을 확인하였다. 3장에서는 압축성 유체의 유량 특성 및 각종 유량계수에 관해 고찰하고, 각종 유량계수간의 환산관계를 도출하였다. 4장에서는 등온화용기 및 등온화용기를 이용한 유량계측의 원리를 소개하고 오차요인을 분석하였다. 분석결과, 본 누설계측법의 계측오차는 0.4% 이하일 것으로 추정되었다. 5장에서는 스톱법을 이용하여 유량 및 충전재의 질량 등이 등온화용기의 온도특성에 미치는 영향을 분석하였다. 또한 등온화용기의 수치모델을 제시하고 실험결과와 비교하여 나타내었다. 5장의 실험 및 수치해석 결과를 통해 규명할 수 있었던 등온화용기의 온도특성은 다음과 같이 요약된다. 1) 등온화용기의 전열특성은 용기내 공기와 충전재 사이의 열전도 현상에 의해 지배된다. 2) 등온화용기의 온도특성은 용기에 충전하는 충전재의 단위 체적 당의 전열면적에 의해 규정할 수 있다. 3) 등온성을 향상시키기 위해서는 전열면적을 확대하는 것이 가장 효과적이다. 4) 충전재를 용기체적의 10% 비율로 충전하게 되는 경우, 용기내 온도변화를 1[K] 미만으로 억제할 수 있다. 5) 등온화용기와 데드볼륨(일반용기)를 연결하였을 경우, 등온화용기의 등온성을 유지하기 위해서는 데드볼륨의 체적이 등온화용기 체적의 3.5배 이하가 되어야 한다, 따라서 이를 이용하면 누설유량계측을 위해 실린더의 체적에 따라 등온화용기의 적정체적을 규정할 수 있다. 6장에서는 등온화용기의 압력응답을 이용하여 유량의 특성, 즉 소닉 컨덕턴스와 임계압력비를 도출하였다. 도출된 소닉 컨덕턴스를 이용하면 시험압력별로 변화하는 누설유량을 쉽게 추정 할 수 있다. 또한, 충전재의 충전비율에 따른 유동저항을 검토하였으며, 누설 유량과 같이 미소 유량에서는 충전재를 용기체적의 10% 비율로 충전하여도 그에 따른 유동저항을 무시 할 수 있음을 확인하였다. 따라서 본 논문에서는 누설측정을 위한 등온화용기 충전재의 비율을 10%로 최종 정의하였다. 7장에서는 정의된 등온화용기를 이용하여 공기압 실린더, 밸브 및 레귤레이터의 누설계측회로와 계측방법을 제안하였고, 제안한 방법을 적용하여 누설유량을 계측하였다.

철계-형상기억합금 스터럽으로 보강된 철근콘크리트 보의 전단거동

지상원 충북대학교 2022 국내석사

This paper presents the experimental and analytical results of reinforced concrete beams reinforced with Fe-SMA stirrups to improve shear performance. The specimen prepared for the experiment is 300mm wide, 500mm high, and 2,800mm long. The shear performance of the specimens reinforced with Fe-SMA stirrups was evaluated through a four-point load test. Experimental variables considered whether Fe-SMA was reinforced(non-reinforcement, reinforcement), reinforcement spacing(200mm, 300mm), and whether or not it was activated(non-activation, activation). Half of the specimen for shear behavior evaluation was fully reinforced with general rebar stirrup, and the other half was reinforced with Fe-SMA stirrup. As a result of the experiment, as the reinforcement spacing of Fe-SMA stirrup decreased, the shear crack height of the fully reinforced part increased, and the number of shear cracks decreased according to the activation of Fe-SMA. The ultimate load of the specimen with Fe-SMA stirrup spacing of 300mm, 200mm increased by 73% and 121%, respectively, compared to the ultimate load of the non-reinforced specimen. In addition, the ultimate load of the specimen increased by an average of 7.6% according to the Fe-SMA activation, and as a result of comparing the deflection at 500kN, the reinforcement spacing and activation decreased the deflection of the beam. This is considered to be because the transverse pre-constraint force of the reinforced concrete beam was applied by the activation of the Fe-SMA stirrup. Finite element analysis of specimens reinforced with Fe-SMA stirrups was performed through LS-DYNA, a commercial structural analysis program. As material models for finite element analysis, MAT_145, MAT_24, and MAT_4 models were used for concrete, reinforcing bars, and Fe-SMA stirrups, respectively. In this case, displacement control was used as the loading method of the analysis model. In order to verify the reliability of the proposed finite element analysis model, a reproducible analysis of the experimental study conducted by Czaderski et al. was performed. As a result of the reproducible analysis, it was confirmed that the deflection and ultimate load showed low errors within 1% and 9.3%, respectively, compared to the experimental results. Reproducible analysis of the experimental results of this study was performed using the proposed finite element analysis model. The ultimate load and ultimate deflection of the specimen derived through reproducible analysis showed relatively small errors of 1.8% and 9.5% on average from the experimental results. In addition, the proposed finite element analysis model realized the fracture shape of the specimen, the increase in stiffness, and the strain rate of the member relatively accurately. Therefore, it is thought that the finite element analysis model proposed in this study can be effecitely applied to predict the behavior of members reinforced with Fe-SMA stirrups. In addition, through the analysis of the experimental and analysis results, it was confirmed that shear reinforcement through Fe-SMA stirrup was effective in improving the usability of the member compared to the existing shear reinforcement.

기니 픽 회장의 연동 운동에 미치는 5-hydroxytryptamine4 수용체 효현제인 tegaserod의 효과

지상원 연세대학교 대학원 2002 국내석사

철계-형상기억합금 기반 활성 구속압이 적용된 RC 부재의 거동

지상원 충북대학교 일반대학원 2025 국내박사

This study evaluates the behavior of Reinforced Concrete(RC) members with active confining pressure using Fe-based Shape Memory Alloy(Fe-SMA) and presents experimental and analytical results on the shear and uniaxial compressive behavior of RC members actively confined with Fe-SMA. To evaluate the effect of active confining pressure of Fe-SMA on RC members, RC beams and columns with Fe-SMA stirrups and spirals were fabricated. To evaluate the shear behavior of RC beams confined with Fe-SMA stirrups, the type of confinement, shear span ratio, presence or absence and reinforcement spacing of Fe-SMA stirrups were considered as experimental variables. The shear strength increased by 84.54 % to 114.09 % compared to specimens without Fe-SMA stirrups. The activation of Fe-SMA stirrups reduced the number of shear cracks and improved the stiffness of RC beams. However, the effect of active confinement of Fe-SMA stirrups on shear strength was minimal. Additionally, a section analysis model based on the Modified Compression Field Theory(MCFT) was proposed to predict the shear behavior of RC beams confined with Fe-SMA stirrups. The predicted shear strength and corresponding deflection results showed ratios of 0.94 and 0.93 to the experimental results, respectively, indicating that the proposed model can accurately predict the shear behavior considering the reinforcement spacing and activation of Fe-SMA. To evaluate the uniaxial compressive behavior of RC columns actively confined with Fe-SMA spirals, the concrete compressive strength, type of confinement, pitch and activation temperature of Fe-SMA spirals were considered as experimental variables. The failure behavior of RC column specimens improved from brittle to ductile by confining them with Fe-SMA spirals. The active confinement effect due to the activation and increased activation temperature of Fe-SMA was more pronounced in specimens with smaller pitch and lower concrete compressive strength. In particular, the maximum compressive strength of RC columns actively confined with 30 mm spaced Fe-SMA spirals increased by an average of 98.87 % compared to unconfined columns. Furthermore, a stress-strain model was proposed to predict the uniaxial compressive behavior of RC columns actively confined with Fe-SMA spirals. The predicted maximum compressive strength of concrete, compared with the experimental results from this study and other researchers, showed a ratio and coefficient of variation of 0.99 and 5.72 %, respectively. The predicted strain corresponding to the maximum compressive strength of concrete showed a ratio and coefficient of variation of 1.08 and 16.72 %, respectively, indicating relatively high accuracy. Therefore, the proposed model is considered to accurately predict the uniaxial compressive behavior of RC columns actively confined with Fe-SMA spirals.

Integration of plasmonic nanoantennas on vertically-aligned silicon annowire arrays for solar cell and photodetector applications

지상원 Hanyang Univ. 2012 국내박사

한글 본문용 폰트의 가로짜기.세로짜기 비교 분석

지상원 영남대학교 문화예술디자인대학원 2020 국내석사

한글은 창제 당시 한자와 병기하기 위하여 세로로 쓰기 시작하였으며, 가로쓰기와 세로쓰기 모두 가능한 문자이다. 우리나라는 시대적 상황 및 한글의 기계화와 표준화를 통해 세로쓰기에서 가로쓰기로 급격한 변화가 이루어졌으며, 이러한 시대의 흐름에 따라 디자인 분야에서도 가로쓰기 사용이 일반화되어 있다. 세로쓰기는 획일화된 가로쓰기에서 벗어나 다양한 디자인적 해석이 가능하며, 한글 타이포그래피만의 특징을 부각시켜 줄 수 있는 대표적인 요소이자 개성 있는 디자인을 가능하게 할 수 있다. 본 연구는 편집 디자이너로써 정보를 전달하기 위해 큰 비중을 차지하고 있는 본문용 폰트 분석을 통해 가로짜기와 세로짜기 조판 속 한글 사용법 차이를 연구하였다. 이를 통해 향후 한글 세로쓰기 활성화를 위하여 추구해야 할 점과 전문적인 타이포그래피 교육을 받지 않은 사람들도 쉽게 사용할 수 있는 관점의 폰트 사용을 함께 고민하고 더 나아가 한글 세로짜기 활성화를 모색함에 의의가 있다. 연구를 위하여 다국어 조판방법, 한글 가로짜기 전환 과정, 문자의 방향성, 세로짜기에 대한 선행 연구 및 편집디자인에서 한글 세로짜기의 가능성을 고찰을 하였다. 선호도가 높은 한글 본문용 폰트 7종을 대상으로 글자의 방향성에 따른 폰트 비교 분석을 실시하였으며, 기본적인 조판 환경, 동일한 본문 텍스트 그대로 가로와 세로로 조판하여 폰트의 형태적인 특징과 글줄 이미지 관점으로 한정하여 비교 분석하였다. 본 연구를 통해 각 폰트별 특징과 세로짜기에서 나타나는 현상을 파악할 수 있었다. 공통적으로 세로짜기에서 나타나는 현상은 가로짜기에 비해 글자가 붙어보이며, 글줄의 길이가 길어졌다. 그리고 로마자, 숫자, 문장부호가 90°로 회전하여 조판이 되었으며, 한글과 시각흐름선이 맞지 않는 현상이 발생하였다. 이에 따라 시각적 조정이 필요하여, 세로짜기 조판 시 유의점에 대하여 제안하였다. 한글 세로짜기는 역사적·디자인적 가치가 모두 높은 쓰기 방식이며, 지속적으로 시도되어야 한다. 이러한 세로쓰기의 저변 확대를 위해서는 디자이너들의 다양한 시도와 연구도 이루어져야 하며, 기본 접근성도 쉬워야한다. 하지만 아직 우리나라에서 세로짜기 활성화를 위한 여건은 많이 부족하다. 세로짜기 전용 폰트가 너무 적으며, 지원해주는 프로그램과 한글 폰트 사용에도 여러 문제점이 발생한다. 이처럼 한글 세로짜기 활성화를 위해서는 디자인을 하는 편집 디자이너만의 몫이 아니라 편집용 프로그램과 폰트 개발 시에도 논의되어야 하며, 사용 환경 또한 분명히 개선되어야 한다. 향후 한글 세로짜기 사용이 확대되어 보다 다양하고 한글만의 특징을 살린 타이포그래피 문화가 활성화 되기를 기대한다. Hangeul (the Korean alphabet), at its creation, was supposed to be written vertically to be written together with Chinese characters, and it is available for both horizontal writing and vertical writing. According to times' situations and the mechanization and standardization of Hangeul, Korea made a rapid change from vertical writing to horizontal writing, and according to such trends, horizontal writing has been generalized in the field of design as well. The vertical writing makes it possible to shed the unified horizontal writing to be open to diverse design, and it can highlight the unique typographical features of Hangeul, making it possible to produce unique design. This study examines the comparison of horizontal typesetting and vertical typesetting of Hangeul through the analysis of text fonts of Hangeul to allow designers to deliver information. This study thus examines things to do for activating the vertical writing of Hangeul, including how to enable not only designers but even ordinary people to easily use fonts of Hangeul. In this regard, this study further examines multi-language typesetting methods, the process of transferring to vertical writing of Hangeul, direction of characters, previous studies on vertical writing, and the possibility of vertical typesetting in edition design. Seven types of popular Korean text fonts were examined to analyzer their direction. In the basic typesetting environment, using the horizontal and vertical typesetting of the same text, morphological features of fonts and the character line image were compared and analyzed. Through such process, features of individual fonts and their appearance in vertical typesetting were identified. Commonly, their appearance in vertical typesetting, compared to horizontal typesetting, looked like individual characters being attached, and the character lines were lengthened. And, Roman alphabet, numbers, and punctuation marks turned 90° in typesetting, and Hangeul and visual flow line did not match. Thus, visual adjustment was required, and cautions for vertical typesetting were also proposed. The vertical typesetting of Hangeul boasts high historical and design values and should continue to be attempted. To expand the base of using vertical writing, designers should make diverse attempts and studies, and vertical typesetting should basically be easy to access. However, the conditions have yet to be further secured to activate vertical typesetting in Korea. Exclusive fonts for vertical typesetting have yet to be further developed, including the supportive programs and Hangeul fonts. As such, to activate the vertical typesetting of Hangeul, not only designers should make efforts, but programs and fonts should also be developed, and the environment for using vertical typesetting should be improved. It is expected to expand the use of vertical typesetting of Hangeul so as to activate the typographical culture of using the diverse features of Hangeul.

One-step fabrication of inorganic-organic hybrid surfaces

지상원 中央大學校 大學院 2017 국내석사

공기압 동력 전달 관로의 동특성을 포함한 위치 제어계 모델링에 관한 연구

지상원 부경대학교 대학원 2006 국내석사

船舶衝突의 損害賠償責任法理에 관한 硏究

지상원 韓國海洋大學校 1996 국내박사

플라즈모닉 나노안테나를 탑재한 실리콘 나노선 어레이의 솔라셀 및 포토디렉터 특성에 관한 연구

지상원 한양대학교 대학원 2012 국내박사

Group IV semiconductors including Si and Ge are the key materials in current or future nanoelectronic and optoelectronic devices. In particular, one dimensional vertical Si arrays have enormous potential as building blocks for applications such as photodetector and solar cell devices. The vertical wire arrays have the geometrically beneficial effects in these devices due to efficient coupling of incoming photons, wide tolerance of light polarization, and reduced material consumption. In this perspective, we discuss the fabrication of vertically-aligned Si-based wire array for realization of low cost and efficient electric or energy harvesting devices. Integration of Al-doped ZnO (AZO) or plasmonic nanoantenna on this vertical nanowire structure enables photodetection in a certain range of wavelengths from ultraviolet (UV) to near infrared (NIR). Transparent Al-doped ZnO (AZO) forms Schottky or n+-p heterojunction with p-type Si nanowire array, which allow efficient carrier collection. Conformal coating of AZO films enables us simply to fabricate the radial heterojunction on vertical nanowire array by using co-sputtering method, enhancing the performance of UV photodetector via increase of light active surface area and an antireflection effect. Resonant plasmonic nanoantennas (NAs) have the potential to significantly modify the optical response via near-field coupling of strongly-enhanced electromagnetic fields. The optical NAs that exhibit a strong resonant interaction with photons concentrate light into a sub-wavelength volume, which makes them appropriate for enhancing the performance of photoactive devices, such as solar cells, light emitting diodes, and photodetectors. A simple nanostructure that optimally integrates the NAs should be effective for converting the concentrated light into a flow of electrons. In particular, high refractive-index silicon nanowire (~100 nm) can exhibit guided mode resonance as a cavity which confine and trap the light. Hence, we suggest a near infrared (NIR) photodetector device consisting of silicon nanowires and Au NAs. Especially, hemispherical Au NA can remarkably amplify the intensity of the near-infrared optical field, while suppressing visible-range guided mode excitation of Si nanowire. The Au NA also can form Schottky contacts with Si nanowires and increase efficient carrier collection. All these traits enable our photodetector to possess an NIR-selective enhanced response, thereby overcoming the inherent poor optical absorption of Si in the NIR wavelengths.