• 공업화학
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• 제8권5호
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• pp.771-776
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• 1997

여러 형태의 탄산칼슘을 합성하였다. 이렇게 합성된 여러형태의 탄산칼슘을 혼합기에 넣어 PP와 혼합하여 PP/$CaCO_3$ 복합재료를 제조하였다. 제조된 복합재료를 입자의 형태에 따른 결정화온도, 용융열, 구정의 크기 그리고 기계적성질에 미치는 영향을 조사한 결과 입자의 형태가 결정화온도와 용융열 그리고 구정의 크피에 많은 영향이 있음을 알 수 있었다. 특히, vaterite를 혼합하였을 경우 다른 입자에 비하여 구정의 크기는 적었으나 결정화도는 증가하였으며, 이로 인해 인장강도와 영율은 다른 입자에 비하여 높은 값을 나타내었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.730-733
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• 2010

본 논문은 녹색조명설비의 구현으로 얇은 패널구조의 LED 조명등을 제작하여 가로등조명, 수중배양 양식조명, 집어등 및 수중탐사의 특수조명 활용성을 확인하였다. 제작된 패널구조의 녹색조명등은 상기한 용도의 조명등으로서 매우 탁월함이 확인되었다. 그 중 집어등의 경우는, 작은 치어 등의 미세생물체와 어류의 조광이동성 및 군집 활동성 증진에 효과적이었으며, 수중배양 양식 조명에서는 녹색 조류, 해초, 수초 및 각종 유기체의 광합성 성장에 유용하였고, 특히 수중조명장치로서의 방수성 및 방열작용의 탁월성이 확인되었다.

• Design & Manufacturing
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• 제12권3호
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• pp.36-41
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• 2018

Metal 3D printing is very useful for making the injection molds containing complex conformal cooling channels. The most important issue of the 3D printed molds is cost and life cycle. However, powder bed fusion (PBF) methods are vulnerable to fatigue loading because of the presence of pores and rough surfaces. In the present study, the fatigue test was performed to obtain fatigue analysis input data for predicting the durability of a 3D printed injection mold core. The metal 3D printer used to manufacture the specimen was OPM250L from Sodick, and the metal powder material was maraging steel. The ultrasonic fatigue testing method was adopted for the fatigue test. A key advantage of the ultrasonic fatigue method is that $10^8{\sim}10^9$ long cycle test data or more could be obtained within a relatively short period. Based on the results of the experiment, the effect of heat treatment was negligible. However, there was an apparent difference in durability depending on the presence or absence of the surface treatment.

• Nuclear Engineering and Technology
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• 제56권8호
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• pp.2990-2998
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• 2024

In ITER, the evaluation of the activated water radiation source and its impact on the radiological levels is necessary to demonstrate compliance with the safety requirements. The use of simplified or conservative approaches often results in the application of expensive constraints on the installation that impact its economics, operations, and construction schedule. In this work, we propose a novel methodology to calculate the activated water source term with a higher degree of realism. The methodology is based on the coupling of a system-level code with a Computational Fluid Dynamics (CFD) code in an explicit, one-way approach. We apply this methodology to the evaluation of the16N radioisotope within the ITER Vacuum Vessel Primary Heat Transfer System (VV-PHTS) cooling circuit in a steady-state and transient scenarios. We chose this system since previous analyses of the VV-PHTS were done with simple, ad-hoc calculations that yielded results that differed by up to a factor of five, underscoring a higher level of uncertainty. As a result, we generate a computational model of the source term that can be used to evaluate the radiological condition surrounding the cooling systems during the operations.

• 태양에너지
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• 제19권2호
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• pp.57-65
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• 1999

[ $H_2O$ ]-NaCl혼합물을 냉축열재로 선택하였으며, 이 혼합물의 상변화온도를 몰농도 변화에 의하여 조절하였다. 그리고 고농도와 저농도의 NaCl과 $H_2O$가 ion-dipole interaction으로 결합하는 구조를 그림으로 가시화하고 가열, 냉각과정에서 $H_2O$-NaCl이 동결, 융해하는 현상을 도시하므로서 융해와 동결과정에서 상변화온도가 2단계로 나타나는 구조적 원인을 구명하였으며, NaCl의 농도변화에 따른 상변화온도를 이론적으로 분석하므로서 실험 및 이론분석 결과의 타당성을 증명할 수 있도록 하였다.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
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• pp.94-99
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• 2000

Bioluminescence is being used as a prevailing reporter of gene expression in microorganisms and mammalian cells. Bacterial bioluminescence draws special attention from environmental biotechnologists since it has many advantageous characteristics, such as no requirement of extra substractes, highly sensitive, and on-line measurability. Using bacterial bioluminescence as a reporter of toxicity has replaced the classical toxicity monitoring technology of using fish or daphnia with a cutting-edge technology. Fusion of bacterial stress promoters, which control the transcription of stress genes corresponding to heat-shock, DNA-, or oxidative-damaging stress, to the bacterial lux operon has resulted in the development of novel toxicity biosensors with a short measurement time, enhanced sensitivity, and ease and convenient usage. Therefore, these recombinant bioluminescent bacteria are expected to induce bacterial bioluminescence when the cells are exposed to stressful conditions, including toxic chemicals. We have used these recombinant bioluminescent bacteria in order to develop toxicity biosensors in a continuous, portable, or in-situ measurement from for air, water, and soil environments. All the data obtained from these toxicity biosensors for these environments were found to be repeatable and reproducible, and the minimum detection level of toxicity was found to be ppb (part per billion) levels for specific chemicals.

• Fibers and Polymers
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• 제4권2호
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• pp.59-65
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• 2003

PLA/LPCL/HPCL blends composed of poly(lactic acid) (PLA), low molecular weight poly($\varepsilon$-caprolactone) (LPCL), and high molecular weight poly($\varepsilon$-caprolactone) (HPCL) were prepared by melt blending for bioabsorbable fila-ment sutures. The effects of blend composition and blending time on the ester interchange reaction by alcoholysis in the PLA/LPCL/HPCL blends were studied. Their thermal properties and the miscibility due to the ester interchange reaction were investigated by $^1{H-NMR}$, DSC, X-ray, and UTM analyses. The hydroxyl group contents of LPCL in the blends decreafed by the ester interchange reaction due to alcoholysis. Thus, the copolymer was formed by the ester interchange reaction at $200^{\circ}C$ for 30-60 minutes. The thermal properties of PLA/LPCL/HPCL blends such as melting temperature and heat of fusion decreased with increasing ester interchange reaction levels. However, the miscibility among the three poly-mers was improved greatly by ester interchange reaction. Tensile strength and modulus of PLA/LPCL/HPCL blend fibers increased with increasing HPCL content, while the elongation at break of the blend fibers increased with increasing LPCL content.

• 한국의류학회지
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• 제23권4호
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• pp.584-592
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• 1999

Highly conductive polyaniline(PAn)-nylon 6 composite fabric was prepared by immersing the nylon 6 fabric in 0.5M aniline+0.35M HCl aqueous solution at 4$0^{\circ}C$ for 2hours, Polymerization was then followed by mixing the prepared oxidant and dopant solution(0.5M(NH4)2S2O+0.35M HCl) to the diffusion bath at 5$^{\circ}C$ for 30 minutes. The conductivity of prepared PAn-nylon 6 composite fabrics reached as high as 0.5$\times$10-1S/cm. Their conductivity were significantly affected by the aniline and oxidant concentration. As compared to those of nylon 6 fabric heat of fusion melting point the degree of crystallinity and tensile strength of PAn-nylon 6 did not significantly changed by inclusion of PAn. In the aspect of serviceability wheras the fabric conductivity was significantly decreased after multiple washion no significant changes in the fabric conductivity were observed after abrading the composite fabric over 50 cycles. However we found that the fabric conductivity could be recovered by acid re-doping with HCl.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1997년도 특별강연 및 춘계학술발표 개요집
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• pp.65-68
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• 1997

Fracture behavior of ex-serviced 1Cr-0.5Mo steel was measured at room(24$^{\circ}C$) and elevated(538$^{\circ}C$) temperature and compared with that measured with virgin 1Cr-0.5Mo steel. Compact C(T) specimens were machined from the base and welded test materials. In case of the C(T) specimens of the weld, fatigue precrack was introduced along the fusion line so that a crack growth should occur along the region of heat affected zone. It was observed that the J-R curve of the serviced material was significantly lower than that of the virgin material at room temperature. Brittle fracture was observed in the serviced material. On the other hand at elevated temperature no noticeable difference was found between the J-R curves of the virgin and the serviced material. The measured J-R curves were also compared with those of the 1.25Cr-0.5Mo steel from other literatures. Optical microscopy and SEM examination of the serviced material reveal the carbide in/along the grain boundary which shows material degradation due to long-term usage.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.217-221
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• 2002

In the coarse grain HAZ adjacent to the fusion line, most of the TiN particles in conventional Ti added steel are dissolved and austenite grain growth is easily occupied during welding process. To avoid this difficulty, thermal stability of TiN particle is improved by increasing the nitrogen content in steel. In this study, the effect of high nitrogen TiN particle on preventing austenite grain growth in HAZ was investigated. Increased thermal stability of TiN particle is helpful for preventing the austenite grain growth by pinning effect. High nitrogen TiN particle in simulated HAZ were not dissolved even at high temperature such as 1400 C and prevented the austenite grain growth in simulated HAZ. Owing to small austenite grain size in HAZ the width of coarse grain HAZ in high nitrogen TiN steel was decreased to 1/10 of conventional TiN steel. Even high heat input welding, the microstructure of coarse grain HAZ consisted of fine polygonal ferrite and pearlite and toughness of coarse grain HAZ was significantly improved.