• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.849-855
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• 2017

The development of a staged combustion cycle engine with higher perfomance is essential to provide higher transport capability of space launch vehicles. The combustor head of engine has a cone-shaped head and its manifold of combustor has a very complicated structure. The head and manifold have been manufactured by casting or machining methode. Metal 3D printing technologies are recently known as one of promising methods to improve manufacturing process for them because they are possible to over come limitations of the two methods. In this paper, a selective laser sintering method is used to make test materials and their physical properties are studying by changing its operation parameters to establish the better processing conditions. It is found that the 3D printing method is acceptable to manufacturing the head or manifold of combustor for staged combustion cycle engine.

• Journal of Conservation Science
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• v.36 no.6
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• pp.483-493
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• 2020

In this paper, we present a nondestructive analysis using X-ray and microscopic investigation to detect the structure, manufacturing technique and preservation status of the Goryeo lacquered box Inlaid with Mother-of-pearl Chrysanthemum and Scroll Design (Goryeo Lacquered Box). We confirm that the Goryeo Lacquered Box consists of the soft wood as the basic material. The soft wood was coated with textile and then lacquered. The box structure of the Goryeo Lacquered Box was formed of wooden boards with wood plants added to the side, after processing into a trefoil-shaped. The wooden sides of the Goryeo Lacquered Box were cut at regular intervals for easier processing into a curved shape. Moter-of-pearl, tortoiseshell, and metal wire were used to decorate the surface. mother-of pearl was the cutting processing, and tortoiseshell was used for back coloring. The metal line was constructed using one line and twist line.

• The monthly packaging world
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• s.230
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• pp.92-99
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• 2012

KOREA STAR AWARDS는 패키징 $\triangle$완제품 $\triangle$재료(플라스틱, 종이 판지, 금속, 유리, 목재, 복합소재) $\triangle$친환경 $\triangle$기계(설비) 및 관련 부품 $\triangle$ 인쇄(라벨링) $\triangle$부자재 $\triangle$생산 및 가공공정 $\triangle$패키징 디자인 등의 분야에서 신기술 개발과 지속가능성을 통해 패키징 산업 발전에 기여한 기업, 그리고 패키징 관련 정책연구, 기술개발, 패키징산업 육성에 기여한 개인에게 시상. 2012 KOREA STAR AWARDS는 코리아스타상(기업, 학생, 공로부문)으로 지식경제부장관상(상장4점, 표창2점), 한국생산기술연구원장상(상장 12점, 표창1점), 한국포장기술사회장상(상장 20점) 총 39점 시상. 코리아스타상 기업부문 지식경제부장관상은 '에이스기계 종이상자 자동접착기의 패스트 폴딩 장치', 'LG생활건강 이자녹스 SMART 진동시리즈', '삼성전자 냉장고 친환경 재사용 포장', '한국에이버리 친환경 수분리성 점착라벨' 4개 제품 수상. 코리아스타상 공로부문 지식경제부장관표창은 (주)경연전람 김영수 대표와 김수일포장개발연구소 김수일 소장 수여. 본 고에서는 "2011 미래패키징 신기술 정부포상" 수상작들의 패키징 동향 및 유공자들의 공적 내용을 살펴보도록 한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.111-111
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• 2017

쇼트피닝 기술은 크게 피로강도 향상을 위한 쇼트피닝(shot peening), 재료의 청정 및 도장 품질 향상을 위한 쇼트블라스트(shot blast) 그리고 쇼트피닝 시 판재의 변형되는 성질을 이용한 핀포밍(peen forming) 등으로 구분할 수 있다. 그 중 본 연구에서는 해양산업 분야에서 널리 사용되는 회주철의 효과적인 내구성 향상을 위해 쇼트피닝 기술을 적용하였다. 그러나 쇼트피닝 기술 적용에 있어서 가장 중요한 것은 제품의 균일성, 정확성, 신뢰성을 확보하기 위해 쇼트피닝 강도를 제어하는 여러 가지 변수들에 대하여 최적 상태를 유지하는 것이다. 따라서 회주철에 대한 최적 쇼트피닝 분사조건 규명작업은 반드시 쇼트피닝 가공 전에 수반되어야만 한다. 그 일환으로 실험은 쇼트피닝 분사시간과 분사압력을 변수로 하여 회주철 표면에 적용하였으며, 기계적 특성 평가를 통해 최적의 쇼트피닝 조건을 규명하고자 하였다. 쇼트피닝 분사조건에 따른 회주철의 내구성을 평가하기 위해 캐비테이션 실험을 실시하였으며, 경도 측정, 횡단면 관찰 및 표면의 3D 현미경 관찰 등을 통해 기계적 특성을 분석하였다. 캐비테이션 실험은 ASTM G32 규정에 의거하여 천연해수 내 $30^{\circ}C$에서 $50{\mu}m$의 진폭으로 실시하였다. 실험 후에는 주사전자현미경으로 손상표면을 관찰하였으며, 손상 정도를 비교하기 위해 무게 감소량을 계측하여 상호 비교/분석하였다.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.729-732
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• 2010

본 논문에서는 다시마를 이용한 기능성 음용수를 개발하기 위한 연구를 진행하였다. 다시마는 당뇨병과 같은 성인병 예방에 특효가 있을 뿐만 아니라 체질개선효과 및 갑상선 질환의 예방, 변비예방 효과, 탈모치료 효과 등 다양한 효능을 가지고 있다. 이러한 다시마는 현재 채 볶음, 다시마튀각, 다시마 무침, 다시마 말이 등 다양한 요리의 재료가 될 뿐만 아니라 다양한 요리의 맛을 해는 조미료로서 많이 사용 되고 있다. 하지만 이런 다시마를 조미료로서 사용하기 위한 가공과정이 복잡하여 가정에서는 쉽게 사용하지 못할 뿐만 아니라 시중에 파는 가공 다시마의 경우 다양한 화학 첨가제가 들어가 건강한 식생활에 적절치 못하고 다시마를 이용한 요리들은 우리가 쉽게 접할 수 없는 요리들이 대부분이어서 우리가 생활하는데 있어서 다시마를 쉽게 접하기가 어렵다. 따라서, 우리는 이러한 다시마를 실생활에서 쉽게 접하기 위하여 물처럼 마시는 다시마에 대한 연구를 진행하였다. 다시마를 끓는 물을 이용하여 우려내 맛을 평가 했을 뿐만 아니라 해조류 특유의 비릿한 맛과 향을 제거하기 위하여 감초, 레몬, 파, 녹차, 생강 등을 이용하였고, 그 결과 다시마의 비릿한 향과 맛을 잡아 낼 수 있는 생각이라는 해결책을 찾아내었다. 그리고 다시마와 생강의 비율을 조절 하고 다시마를 우려내는 시간을 조절하여 맛을 평가하였다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.337-343
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• 2004

This paper presents an experimental study of friction and wear properties of a unidirectional oriented continuous crbon-fiber reinforced epoxy composite at the ambient temperature. Friction and wear experiments were conducted in the three principal sliding direction of the fiber orientation in the composite were selected against the stainless steel counterpart specularly processed were using a pin -on-disc apparatus. Friction coefficient and specific wear rate at various normal loads and sliding velocities wear determined. When sliding took place against smooth and hard counterpart, the hightest were resistance and the lowest friction coefficient were observed in the anti-parallel direction. The wear track of the worn specimens was examined with a scanning electron microscope(SEM) to observe the damaged fibers on the surface. In addition, SEM observations of the worn surfaces allowed to identify the involved different wear mechanisms.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.76-84
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• 2021

In this study, an optimal stiffness model of the C-frame, which was supporting the mold and tool load, was proposed to obtain quality self-piercing riveting (SPR) joining. First, the load path acting on the C-frame structure was identified using topology optimization. Then, a final suggested model was proposed based on the load path results. Stiffness and strength analyses were performed for a rivet pressing force of 7.3 [t] to compare the design performance of the final proposed model with that of the initial model. Moreover, to examine the reliability of continuous and repeated processes, vibration analysis was performed and the dynamic stiffness of the final proposed model was reviewed. Additionally, fatigue analysis was performed to ascertain the fatigue characteristics due to simple repetitive loading. Finally, stiffness test was performed for the final proposed model to verify the analysis results. The obtained results differed from the analysis result by 2.9%. Consequently, the performance of the final proposed model was superior to that of the initial model with respect to not only the SPR fastening quality but also the reliability of continuous and repetitive processes.

• Transactions of Materials Processing
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• v.30 no.1
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• pp.5-15
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• 2021

The effects of heat treatments (T6 and T73) on the microstructure, mechanical properties, and high cycle fatigue behavior of modified AA7075 alloys were investigated. A modified 7075 alloy was manufactured using modified-Mg (Mg-Al2Ca) instead of the conventional element Mg. Based on the microstructure, the average grain size was 4.5 ㎛ (T6) and 5.2 ㎛ (T73). Regardless of heat treatment, the modified AA7075 alloys consisted of Al matrix containing homogeneously distributed Al2CuMg and MgZn2 phases with reduced Fe-intermetallic compound. Room temperature tensile tests showed that the properties of modified 7075-T6 (Y.S.: 622MPa, T.S: 675MPa, elongation: 15.4%) were superior to those of T73 alloy (Y.S.: 492MPa, T.S: 548MPa, elongation: 12.8%). Experimental data show that the fatigue life of T6 was 400 MPa, about 64% of its yield strength. However, the fatigue life of T73 alloy was 330 MPa and 67%. Irrespective of the stress level, all crack initiation points were located on the specimen surface, and no inclusions acting as stress concentrators were seen. Superior mechanical properties and high cycle fatigue behavior of modified AA7075-T6 alloy are attributed to the fine grains and homogeneous distribution of small second phases such as MgZn2 and Al2CuMg, in addition to reduced Fe-intermetallic compounds.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.71-79
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• 2016

Background: It is necessary to analyze radioactivity of naturally occurring radioactive materials (NORM) in products to ensure radiological safety required by Natural Radiation Safety Management Act. The pretreatments for the existing analysis methods require high technology and time. Such destructive pretreatments including grinding and dissolution of samples make impossible to reuse products. We developed a rapid and simple procedure of radioactivity analysis for thorium series in the products containing NORM. Materials and Methods: The developed method requires non-destructive or minimized pretreatment. Radioactivity of the product without pretreatment is initially measured using gamma spectroscopy and then the measured radioactivity is adjusted by considering material composition, mass density, and geometrical shape of the product. The radioactivity adjustment can be made using scaling factors, which is derived by radiation transport Monte Carlo simulation. Necklace, bracelet, male health care product, and tile for health mat were selected as representative products for this study. The products are commonly used by the public and directly contacted with human body and thus resulting in high radiation exposure to the user. Results and Discussion: The scaling factors were derived using MCNPX code and the values ranged from 0.31 to 0.47. If radioactivity of the products is measured without pretreatment, the thorium series may be overestimated by up to 2.8 times. If scaling factors are applied, the difference in radioactivity estimates are reduced to 3-24%. Conclusion : The developed procedure in this study can be used for other products with various materials and shapes and thus ensuring radiological safety.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.188-191
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• 1994

최근 FA, OA 및 공작기계 등의 메카트로닉스 분야와 첨단산업의 눈부신 성장에 따라 그 요소 부품인 소형 모터의 중요성이 점차 강조되고 있다. 특히, 성력화와 시스템의 고성능화 및 경박단소화의 필요성으로 인해 그 구동원인 모터의 고효율화 및 소형경량화가 요구되고 있다. 또한, 근래의 영구자석 재료를 비롯한 소재분야의 발전과 정밀가공 및 제작기술의 발달로 인해 과거보다 우수한 성능을 갖는 정밀 소형 모터의 제작이 가능해지면서 이를 뒷받침하기 위한 보다 정확한 모터특성 해석 및 최적설계의 필요성이 절실하게 요구되고 있다. 본고에서는 소형모터의 해석 및 설계에 대한 비전문가들의 이해를 돕기 위하여 자기 등가회로를 이용 한 해석적인 방법과 수치해석적인 방법에 의한 모터 자기장 해석방법을 소개한다. 그리고 기존의 모터설 계 및 최적설계에 대한 현재까지의 연구결과 및 동향과 앞으로의 전개방향에 대해서 고찰하도록 한다.