• 한국수소및신에너지학회논문집
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• 제30권4호
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• pp.338-346
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• 2019

During last years, hydrogen refueling infrastructure test and devices research for hydrogen station presented a significant growth consisting of the commercialization of fuel cell electric vehicles (FCEVs). However, we still have many challenges for making commercial hydrogen stations such as increased safety and cost reduction. This study demonstrates the low cost hydrogen storage tank (type 2) and effective winding method for high pressure hydrogen storage. We use numerical analysis to verify stress changes inside the wire according to the winding condition. Also liner size, winding wire size and wire tension were studied for the safety and cost down. Results show that the stress of winding wire decreased with increased winding angle and increased the liner diameter. On the other hand, the stress of winding wire increased according to the increased wire thickness and tension.

• 한국초전도ㆍ저온공학회논문지
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• 제25권4호
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• pp.24-27
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• 2023

Until now, many research activities have been conducted to commercialize high-temperature superconducting (HTS) wires for electric applications. Most of all researchers have focused on enhancing the piece length, critical current density, mechanical strength, and throughput of HTS wires. Recently, HTS magnet for generating high magnetic field shows degraded performance due to the deformation of HTS wire by high electro-magnetic force. The deformation can be derived from widthwise thickness non-uniformity of HTS wire mainly caused by wet processes such as electro-polishing of metal substrate and electro-plating of copper. Gradient sputtering process is designed to improve the thickness uniformity of HTS wire along the width direction. Copper stabilizing layer is deposited on HTS wire covered with specially designed mask. In order to evaluate the thickness uniformity of HTS wire after gradient sputtering process, the thickness distribution across the width is measured by using the optical microscope. The results show that the gradient deposition process is an effective method for improving the thickness uniformity of HTS wire.

• 대한두개안면성형외과학회지
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• 제16권3호
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• pp.119-124
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• 2015

Background: The Kirschner wire (K-wire) technique allows stable fixation of bone fragments without periosteal dissection, which often lead to bone segment scattering and loss. The authors used the K-wire fixation to simplify the treatment of laborious comminuted zygomatic bone fracture and report outcomes following the operation. Methods: A single-institution retrospective review was performed for all patients with comminuted zygomatic bone fractures between January 2010 and December 2013. In each patient, the zygoma was reduced and fixed with K-wire, which was drilled from the cheek bone and into the contralateral nasal cavity. For severely displaced fractures, the zygomaticofrontal suture was first fixated with a microplate and the K-wire was used to increase the stability of fixation. Each wire was removed approximately 4 weeks after surgery. Surgical outcomes were evaluated for malar eminence, cheek symmetry, K-wire site scar, and complications (based on a 4-point scale from 0 to 3, where 0 point is 'poor' and 3 points is 'excellent'). Results: The review identified 25 patients meeting inclusion criteria (21 men and 4 women). The mean age was 52 years (range, 15-73 years). The mean follow up duration was 6.2 months. The mean operation time was 21 minutes for K-wire alone (n=7) and 52 minutes for K-wire and plate fixation (n=18). Patients who had received K-wire only fixation had severe underlying diseases or accompanying injuries. The mean postoperative evaluation scores were 2.8 for malar contour and 2.7 for K-wire site scars. The mean patient satisfaction was 2.7. There was one case of inflammation due to the K-wire. Conclusion: The use of K-wire technique was associated with high patient satisfaction in our review. K-wire fixation technique is useful in patient who require reduction of zygomatic bone fractures in a short operating time.

• 한국콘텐츠학회논문지
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• 제10권9호
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• pp.309-317
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• 2010

치과 교정치료를 위하여 스테인리스 선재가 널리 사용되고 있다. 그러나 내식성이 우수한 스테인리스강 선재가 복합적인 구강환경에서 부식되어 구강조직에 과민반응 또는 이상반응이 발생되고 있다. 이러한 문제를 보완하기 위하여 본 연구에서는 초내식성의 듀플렉스 스테인리스 선재를 교정용 선재로 제시하고 자 한다. DSS선재의 교정용 선재로 제시하기 위하여 기계적 강도와 생물학적 안정성을 평가하였다. 기계적 강도는 상용 교정용 SS선재와 6종의 열처리(실온($28^{\circ}C$), $500^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$, $800^{\circ}C$, $900^{\circ}C$)를 실시한 DSS선재를 이용하여 인장강도시험을 실시하였다. 그리고 최적의 강도를 가지는 열처리 조건에서 제작된 DSS선재를 이용하여 굽힘 모멘트 시험을 실시하여 최대 응력과 탄성계수를 산출하였다. 그리고 생물학적 안정성 평가를 위하여 세포성장률 시험을 실시하였다. 선재를 이용하여 금속용출배지를 만들어 세포를 배양 후 세포성장률을 관찰하였다. 기계적 강도 평가 결과 SS선재($8.17\times10^4\;N/mm^2$)와 DSS500($8.05\times10^4\;N/mm^2$)선재가 유사한 기계적 강도를 가졌다(p=0.05). 생물학적 안전성 평가 결과 세포 독성이 없는 것으로 나타났다(p=0.05). 따라서 본 연구에 제시한 초내식성의 듀플렉스 스테인리스 선재가 교정용 선재로 사용이 가능한 것으로 판단된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.66-69
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• 2002

This paper presents deposition and characterizations of microcrystalline silicon$({\mu}c-Si:H)$ films prepared by hot wire chemical vapor deposition at substrate temperature below $300^{\circ}C$. The $SiH_{4}$ concentration$[F(SiH_{4})/F(SiH_{4})+F(H_{2})]$ is critical parameter for the formation of Si films with microcrystalline phase. At 6% of silane concentration, deposited intrinsic ${\mu}c-Si:H$ films shows sufficiently low dark conductivity and high photo sensitivity for solar cell applications. P-type ${\mu}c-Si:H$ films deposited by Hot-Wire CVD also shows good electrical properties by varying the rate of $B_{2}H_{6}$ to $SiH_{4}$ gas. The solar cells with structure of Al/nip ${\mu}c-Si:H$/TCO/glass was fabricated with single chamber Hot-Wire CVD. About 3% solar efficiency was obtained and applicability of HWCVD for thin film solar cells was proven in this research.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.387-390
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• 2002

This paper presents deposition and characterizations of microcrystalline silicon(${\mu}$c-Si:H) films prepared by hot wire chemical vapor deposition at substrate temperature below 300$^{\circ}C$. The SiH$_4$ concentration[F(SiH$_4$)/F(SiH$_4$).+(H$_2$)] is critical parameter for the formation of Si films with microcrystalline phase. At 6% of silane concentration, deposited intrinsic ${\mu}$c-Si:H films shows sufficiently low dark conductivity and high photo sensitivity for solar cell applications. P-type ${\mu}$c-S:H films deposited by Hot-Wire CVD also shows good electrical properties by varying the rate of B$_2$H$\_$6/ to SiH$_4$ gas. The solar cells with structure of Al/nip ${\mu}$c-Si:H/TCO/g1ass was fabricated with single chamber Hot-Wire CVD. About 3% solar efficiency was obtained and applicability of HWCVD for thin film solar cells was proven in this research.

• 대한기계학회논문집
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• 제12권4호
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• pp.900-915
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• 1988

본 연구에서는 주유동 방향이 알려진 3차원 난류유동에서 열선유속계의 경사 형 프로브와 Ⅰ형 프로브를 회전시키므로써 3방향 속도성분과 6방향 레이놀즈 응력을 비교적 간편하고 정확히 측정하는 방법을 고안하여 사용하였다.

• 한국기계가공학회지
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• 제5권4호
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• pp.79-85
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• 2006

Multi-filament hydrostatic extrusion was developed as a fine wire manufacturing process and wire forming experiments were conducted. Also, single wire stretch forming process was proposed in the possibility of obtaining long wire with constant cross-section. In the multi filament extrusion since the workpiece, die and forming facility are in the macro forming circumstance, fine wire and fine hole structure with less than a few micrometer can be easily obtained. Although stretch forming does not use a die in order to avoid the friction problem between the workpiece and the die, it is necessary to have high level of technology to maintain cross-sectional shape and measure in longitudinal direction.

• 전기학회논문지
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• 제57권4호
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• pp.653-659
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• 2008

This paper describes the design of high power transistor packages using high power chip transistor dies, chip capacitors and a new wire bonding technique. Input impedance variation and output power performances according to wire inductance and resistance for internal matching are also discussed. A multi crossing type(MCT) wire bonding technique is proposed to replace the conventional stepping stone type(SST) wire bonding technique, and eventually to improve the output power performances of high power transistor packages. Using the proposed MCT wire bonding technique, it is possible to design high power transistor packages with highly improved output power compared to SST even the package size is kept to be the same.

• 설비공학논문집
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• 제4권2호
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• pp.137-145
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• 1992

coefficient precisely, experiments were carried out in three categories which contain the regime of (1) constant wire temperature (2) constant fluid temperature (3) constant temperature difference between wire and fluid. Measurements were made with electrically heated circular tungsten wire placed normal to air stream at the exit of jet. Heat transfer coefficient was increased with wire temperature increasing and decreased by fluid temperaure increasing and was not changed with varying both temperature if their difference were kept constant.