• 한국기계가공학회지
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• 제15권3호
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• pp.130-134
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• 2016

Due to the need for advanced technologies in the automotive industry, the demand for lighter and safer vehicles has increased. Even though various nonferrous metals, like Aluminum, Magnesium and also Carbon Fiber Reinforced Plastic (CFRP), have been implemented in the automotive industry, a lot of technical research and development is still focused on ferrous metals. In particular, the market volume of High Strength Steel (HSS) parts and Ultra High Strength Steel (UHSS) by hot press forming parts has expanded significantly in all countries' automotive industries. A new tool steel, High Thermal-Conductivity Tool Steel (HTCS), for stamping punches and dies has been developed and introduced by Rovalma Company (Spain), and it is able to support better productivity and quality during hot press forming. The HTCS punches and dies could help to reduce cycle time due to their high thermal conductivity, one of the major factors in hot press forming operation. In this study, test dies were manufactured in order to verify the high thermal conductivity of HTCS material compared to SKD6. In addition, thermal deformation was inspected after the heating and cooling process of hot press forming. After heating and cooling, the test dies were measured by a 3D scanner and compared with the original geometry. The results showed that the thermal deformation and distortion were very small even though the cooling time was reduced by 2 seconds.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 1부
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• pp.495-499
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• 2010

The biocatalytic capture of $CO_2$, and its precipitationas $CaCO_3$, over bovine carbonic anhydrase (BCA) immobilized on a pore-expanded SBA-15 support was investigated. SBA-15 was synthesized using TMB as a pore expander, and the resulting porous silica was characterized by XRD, BET, IR, and FE-SEM analysis. BCA was immobilized on SBA-15 through various approaches, including covalent attachment (BCA-CA), adsorption (BCA-ADS), and cross-linked enzyme aggregation (BCA-CLEA). The immobilization of BCA on SBA-15 was confirmed by the presence of zinc metal in the EDXS analysis. The effects of pH, temperature, storage stability, and reusability on the biocatalytic performance of BCA were characterized by examining para-nitrophenyl acetate (p-NPA) hydrolysis. The $K_{cat}/K_m$ values for p-NPA hydrolysis were 740.05, 660.62, and $680.11M^{-1}s^{-1}$, respectively, where as $K_{cat}/K_m$ for free BCA was $873.76M^{-1}s^{-1}$. The amount of $CaCO_3$ precipitate was measured quantitatively using anion-selective electrode and was found to be 12.41, 11.82, or 11.28 mg $CaCO_3$/mg for BCA-CLEA, BCA-ADS, or BCA-CA, respectively. The present results indicate that the immobilized BCA-CLEA, BCA-ADS, and BCA-CA are green materials, and are tunable, reusable, and promising biocatalysts for $CO_2$ sequestration.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.7-15
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• 2008

Currently existing high-accuracy and high-speed die sets used in reciprocal press create scratches at the surface of guide posts, steel balls, and bushes due to vertical movement of balls with point-contacts between inner surface of bushes and guide posts. Consequently, accuracy of the die set and the life span of the metal mold are reduced. However, those scratches could reduce the pre-load of the steel ball. This research designed and developed a groove-type die set which improves life span of the die set by eliminating point-contacts of steel balls with guide posts. The guide post consisted of a steel-ball retainer, a steel-ball retainer stopper, a guide bush, a guide pin, a snap ring, and a spring. The steel-ball retainer has 72 holes with 8 columns of 9 holes in each column. The inner surface of the guide bush was grinded(surface roughness: $Ra\;\\;0.2{\mu}m$, accuracy: $0\;{\sim}\;-0.002mm$) after NC turning and heat treatment. Also, a line of small intermediate pocket was processed inside of the guide bush for lubrication and elimination of foreign materials. Guide grooves of steel balls were processed using a wire EDM(Electrical Discharge Machining) after heat treatment. With such a design of the guide post stated above, loads against steel balls could be dispersed greatly by the line contacts through the guide groove between the guide post and the guide bush, and the life span of the guide post could be expanded semi-permanently.

• Structural Engineering and Mechanics
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• 제60권4호
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• pp.567-594
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• 2016

The main objective of the current research is estimating the flexural behavior of ferrocement Ribbed Plates reinforced with composite material. Experimental investigation was carried out on fifteen plates; their dimensions were kept constant at 1200 mm in length, 600 mm width and 100 mm thick but with different volume fraction of steel reinforcement and number of ribs. Test specimens were tested until failure under three line loadings with simply supported conditions over a span of 1100 mm. Cracking patterns, tensile and compressive strains, deformation characteristics, ductility ratio, and energy absorption properties were observed and measured at all stages of loadings. Experimental results were compared to analytical models using ANSYS 10 program. Parametric study is presented to look at the variables that can mainly affect the mechanical behaviors of the model such as the change of plate length. The results showed that the ultimate strength, ductility ratio and energy absorption properties of the proposed ribbed plates are affected by the volume fraction and the type of reinforcement, and also proved the effectiveness of expanded metal mesh and woven steel mesh in reinforcing the ribbed ferrocement plates. In addition, the developed ribbed ferrocement plates have high strength, ductility ratio and energy absorption properties and are lighter in weight compared to the conventional RC ribbed plates, which could be useful for developed and developing countries alike. The Finite Element (FE) simulations gave good results comparing with the experimental results.

• 대한기계학회논문집
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• 제17권6호
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• pp.1412-1422
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• 1993

본 연구는 각주형 금형부품을 절삭가공할때 부품의 설계데이터로부터 부품의 형상적인 특징을 추출하여 공정설계시스템인 MOLDCAPP과 작업설계시스템인 COPS에서 사용할 수 있는 정보를 생성함으로써 CAD/CAM의 연결을 자동화할 수 있는 특징형상 인식 시스템을 개발하는 연구로, 특징형상 인식기법의 창안보다는, 가용한 기술의 장 점을 사용하여 각주형 공작물의 기계 절삭가공으로 생성될 수 있는 형상을 특징형상으 로 정의하고 ACIS로 설계된 CAD데이터로부터 정의된 특징형상을 추출하여 각 특징형상 들의 형상 데이터를 결정함으로써 MOLDCAPP, COPS 등의 공절설계시스템의 입력데이터 를 생성할 수 있도록 Fig.1과 같이 설계하였다. 특히 PART시스템과 같이 인식대상이 포괄적이지 않으나, 금형부품상의 특징형상으로 범위를 축소하고 금형부품의 가공특징 을 고려하여 인식규칙을 단순화함으로써 금형가공공정의 CAD/CAM연결에 이용될 수 있도록 하였다.

• 한국진공학회지
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• 제12권3호
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• pp.151-156
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• 2003

저진공 국가표준기인 초음파간섭 수은주압력계를 이용하여 두 개의 용량형 격막식 게이지와 두 개의 공진형 실리콘 게이지를 교정하였다. 용량형 격막식 게이지의 센서부는 금속으로 되어 있으므로 견고하고 과압에 잘 견딜 뿐만 아니라 우수한 분해능을 가지고 있으며, 공진형 실리콘 게이지는 우수한 안정성과 기계적인 충격에 강한 특성을 가지고 있다. 이들의 교정 불확도를 국제표준화기구에서 제정한 측정불확도 표현지침서에 따라 분석하여 비교하였으며, 그 결과 확장불확도의 최대 차이는 교정압력 100 Pa에서 $9\times10^{-3}$Pa 이었다. 또한 공진형 실리콘 게이지의 표준압력에 대한 압력비의 차이가 0.5 % 이내이었으므로 저진공 영역의 전달표준기로 사용이 가능함을 알 수 있었다.

• 대한한의학방제학회지
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• 제23권2호
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• pp.225-233
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• 2015

Objectives : The purpose of this study was to investigate the interpretation of the Pyeongwi-san(PWS) prescription in order to obtain the evidence for clinical applications. Methods and Result : We interpreted on the PWS-related contents based on 15 classic books, analyzed it according to followed categories ; origin, indication and precaution, usage, meaning of name, physiological and pathological situation of PWS, explain about each herbs. Conclusion : 1. PWS was first mentioned in the Bakjebang, its application was enhancing appetite. Application of PWS not only expanded digestive disease, infectious disease, and pain in articular, but also used to toniyfing drug. 2. Generous application method of PWS was ‘Sujunbok(水煎服)’. Pill preparation(丸劑) and decoction with salt(鹽湯劑) were also used 3. "Pyeongwi(平胃)“ in PWS means "flatten the stomach". There are some theory about methodology to "Pyeongwi (平胃)“, one is "drain the pathogen in stomach(敦阜說)”, other is "tonifying stomach's healthy qi(卑監說)“, the other is compromise theory. 4. Most medical literature related application situation of PWS to dampness(濕邪) in stomach. In Gangsulwongobangsunju, there are more detailed explain focused on metal qi(金氣), and fire qi(火氣) 5. Atractylodes japonica Koidz(蒼朮) drys dampness and fortifys the spleen, Magnolia officinalis Rehder(厚朴) eliminates dampness and treats fullness, Citrus reticulata Blanco(陳皮) moves and drains qi, Glycyrrhiza uralensis Fisch(甘草) tonify and harmonize in herbal formula

• 디지털융복합연구
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• 제18권3호
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• pp.299-304
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• 2020

과거 상업광고는 제품이 가지고 있는 기능, 설명, 또는 브랜드를 소개하는 식의 위주로 광고로 제작되었다. 그러나 지금의 광고시장은 스토리텔링 역할이 확대된 소비자의 감성에 맞추어 제품에 감성을 투영시켜 상품을 어필하고 있다. 넛지효과는 경제 행동학적 의미로 올바른 선택에 도움을 줄 수 있다. 이러한 넛지효과가 포함되어있는 스토리텔링에는 사람과 사람들을 소통하게 하고, 그로 인해 소비자와 기업을 소통하게 해주며, 기업이 원하는 방향으로 유도하게 한다. 본 연구는 서울우유의 상업광고를 통하여 넛지효과의 개념을 이해하고 광고 속의 넛지효과와 스토리텔링 사이 상호작용의 분석에 대한 기업의 상업광고가 소비자로 하여 기업의 인식변화에 준 영향을 연구한다. 본 연구는 넛지효과가 가진 영향력에 대한 연구를 목적으로 한다. 본 연구의 결론은 소비자는 넛지효과의 파급력에 영향을 받아 기업의 인식에 어떤 영향을 주었는지에 관한 결과를 보여준다.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.213-218
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• 2011

The scope of homogeneous Lewis acid-catalyzed benzo[N,N]-heterocyclic condensation was expanded to include the use of various metal salts not reported in the literature and $SnCl_2{\cdot}2H_2O$ was finally selected. Among various solid supports activated with $SnCl_2$, heterogeneous $SnCl_2/SiO_2$ proved to be the most effective and significantly higher conversions were achieved compared to $SnCl_2{\cdot}2H_2O$ itself. The results of TG-DTA and BET indicated that dispersed $SnCl_2$ coordinates with surface hydroxyl groups of silica leading to formation of stable Lewis acid sites. Low catalyst loading, operational simplicity, practicability and applicability to various substrates render this eco-friendly approach as an interesting alternative to previously applied procedures.

• 한국안전학회지
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• 제26권4호
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• pp.41-46
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• 2011

The purpose of this paper is to analyze the causes of accidents related to the 3 phase 170 kV gas insulated switchgear of a power system collected from accident sites to secure data for the prevention of similar accidents and provide important points of view regarding diagnosis for the prevention of accidents involving gas insulated switchgears. The analysis results of the causes of accidents involving gas insulated switchgears showed deformation of the manipulation lever installed at the S-phase, disconnection of the insulation rod connection, melting of the upper conductor, a damaged tulip, damage to the lower spacer and the spacer at the breaker, etc. It is believed from this result that the potential for accidents has expanded due to accumulated energy as a result of repeated deterioration. The carbonization depth of a GIS was formed near the screw (T2, T3) used to secure the lower pole of the S-phase tulip. It is not known what has caused the screws to be extruded and melted. However, it is thought that an unbalanced electromagnetic force, micro-discharge, surface discharge, etc., have occurred at that point. In addition, even though 16 years have passed since its installation, there was no installation defect, act of arson, accidental fire, etc. General periodical inspection and diagnosis failed to find the factors causing the accidents. As a system contained in a closed metal container, it has a high risk factor. Therefore, it is necessary to design, install and operate a GIS in accordance with the standard operational procedure (SOP). In addition, it is necessary to apply conversion technology for periodical SF6 gas analysis and precision safety diagnosis. It is expected that tracking and managing these changes in characteristics by recording the results on the history card will provide a significant accident prevention effect.