• 한국유체기계학회 논문집
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• 제17권6호
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• pp.29-37
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• 2014

Non-Newtonian fluid mechanics takes charge of an important role in the oil industries. Especially in the oil well drilling process, the drilling fluid such as mud keeps the drill bit cool and clean during drilling, with suspending drill cuttings and lubricating a drill bit. The purpose of this study is to examine the effect of fluid mud rheological properties to predict different characteristics of non-Newtonian fluid in the mud mixing tank on offshore drilling platforms. In this paper, ANSYS fluent package was used for the simulation to solve the hydrodynamic force and to evaluate mud mixing time. Prediction of the power consumption and the pumping effectiveness has been presented with different operating fluid models as Newtonian and non-Newtonian fluid. The comparison between Newtonain mud model and non-Newtonian mud model is confirmed by the CFD simulation method of drilling mud mixing tank. The results present useful information for the design of the drilling mud mixing tanks and provide some guidance on the use of CFD tool for such non-Newtonian fluid flow.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.269-271
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• 2009

We investigated on the sintering behaviors and electrical properties of photo-sensitive aluminum (Al) electrode materials in plasma display panels. General characteristics of Al electrodes was totally different to that of conventional Ag materials; resistivity was decreased with the increasing of metal particle sizes and the amount of frit content and there is almost no width difference between developed and fired electrodes layers. Microstructures of fired electrodes revealed that Al electrodes had different mechanism on necking between metal particles and making electrical conducting path. Chemical durability (especially, antialkalinity) and adhesion of Al electrodes must be carefully controlled. Nevertheless there are difficulties of processing Al electrodes, we developed and optimized photo-sensitive Al materials as address electrodes without any changes of existing patterning equipment and sintering conditions.

• 한국경제지리학회지
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• 제17권4호
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• pp.660-674
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• 2014

본 논문은 새로운 경제패러다임으로 등장하는 창조경제에서 핵심요소인 창조산업이 갖는 사회통합적 효과를 우리나라 창조산업의 대표적인 집적지인 수도권을 사례로 분석하였다. 먼저 본 연구는 창조산업의 새로운 분류체계를 구축하였고, 이를 토대로 창조산업의 공간분포 특성을 고찰하였다. 총 6개 부문 13개 산업으로 재분류한 창조산업의 특화수준이 수도권 내 시군구별로 차별적으로 나타나고 있기 때문에, 향후 수도권 창조산업 발전전략은 지역 단위별로 정책조합이 다른 차별적인 클러스터 전략을 도모하는 것이 필요하다. 또한 본 연구는 창조산업의 사회통합적 영향을 알아보기 위해 구조방정식 모형을 설정하여 분석하였다. 분석 결과, 창조산업의 성장은 지역발전 역량에 기여하고 있으며, 사회통합의 제 측면에도 긍정적인 영향을 미쳐 사회통합을 촉진시키는 것으로 나타났다.

• 한국산업정보학회논문지
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• 제23권5호
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• pp.103-118
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• 2018

본 논문은 세계산업연관표의 전후방연쇄효과를 이용하여 2000년부터 2014년까지의 한국, 중국, 일본의 1차 산업의 생산유발효과를 비교 분석하였다. 1차 산업의 산업영향력에 관한 연구는 활발히 진행되어 왔으나, 본 논문은 1차 산업 분야에 대한 한국, 중국, 일본의 산업연쇄효과의 차이에 대한 연구라는 점에서 의미가 있다. Fisher(1939)와 Clark(1957)의 1차 산업 분류에 따라 1차 산업을 농림축산업, 임업, 수산업, 광업으로 분류하였다. 분석방법으로는 세계산업연관표를 이용하여 한국, 중국, 일본 3국간 산업연관모형을 만든 후 비교분석하는 것이다. 본 연구의 결과에 따르면, 농림축산업, 광업은 한국, 중국, 일본 각 국가별로 전 후방 연쇄효과에 유의한 차이가 있었고 임업과 수산업의 경우 한국, 중국, 일본의 전 후방 연쇄효과에 부분적으로 유의한 차이가 있었다. 1차 산업의 산업의존도 변화를 4차 산업혁명의 시대에 산업의 전방연쇄효과와 후방연쇄효과를 IO 분석을 통해 각 국가별로 비교함으로서 향후 1차 산업이 나아가야할 방향을 제시하였다.

• 한국의류학회지
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• 제33권7호
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• pp.1152-1163
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• 2009

Product development and marketing that appeal to consumer emotions are important as shown by a variety of product and service industries that integrate fashion and arts into product design and marketing through collaboration. This study attempted to analyze the patterns in the collaborations of fashion and arts across industry disciplines. A total of 278 collaboration cases reported in news articles were collected from internet databases. Cases were categorized into 5 disciplines of fashion-fashion, arts-arts, fashion-arts, fashion-other industries, and arts-other industries, with each category analyzed in frequency distribution and collaboration type along with related partner and industry characteristics. Collaborations with other industries were observed more than internal ones, and individuals (rather than firms) were more involved in collaborations. Though the collaboration characteristics were different by partner category and sub-category, by individual or firm, and by related industries, a variety of collaborations integrating fashion and arts into product design and development, a new brand launching, product line extension, and co-marketing were observed across product and industry disciplines. The study also described fashion and arts that were integrated into consumer life styles.

• Corrosion Science and Technology
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• 제8권6호
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• pp.209-216
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• 2009

In this study the effect of different surface finishing techniques on the pitting corrosion behaviour of a commercial 304 stainless steel alloy was investigated. Surface finishing methods were divided into two categories, i.e. mechanical and chemical. Mechanical treatment methods include power tooling such as grinding, emery paper brushing, stainless steel wire brushing and stainless steel shot blasting. Chemical treatment methods include chemical passivation (phosphoric acid, citric acid, nitric acid) and electro-cleaning (phosphoric acid and citric acid). Potentiodynamic polarization experiments were carried out in 3.5 wt. % NaCl solution at room temp. (20 $^{\circ}C$). The results showed that chemical treatment methods improved the corrosion resistance of stainless steel 304, measured in terms of pitting potential ($E_{pit}$). Corrosion resistance of the specimens was increased in the order of; electro-cleaning > manual passivation > mechanical cleaning. Surface of electro-cleaned specimens was smoother than rest of the surface treatment methods. Chrome content in chemically treated specimens was higher than in mechanically treated specimens as shown by EDX analysis.

• 대한조선학회논문집
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• 제44권2호
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• pp.111-118
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• 2007

In order to investigate the noise characteristics of the different caviation, noise measurements were carried out in a large cavitation tunnel of the Samsuug Ship Model Basin(SSMB). The noise measurements for a 3-dimensional hydrofoil were carried out at the angle of attack of $12^{\circ}$ and $16^{\circ}$ according to the decrease in cavitation number. It is exhibited that sound pressure level(SPL) increased sharply with cavitation inception. The frequency of the noise induced by sheet cavitation was higher than that of tip vortex cavitation in the phase of cavitation inception. Within the range of the high frequency, in the case of fully developed cavitation, sheet cavitation noise was significantly increased in sound pressure level compared with tip vortex cavitation noise. In this study, the noise characteristics of the different cavitation types were considered experimentally and would be utilized as a basis for the analysis of propeller cavitation noise.

• 한국환경보건학회지
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• 제28권4호
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• pp.12-16
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• 2002

Workers' exposure to lead particles with diverse characteristics was assessed using personal cascade impactors in four different industries. Correlation analyses found that total airborne lead (PbA) concentrations could not explain the variation on MMAD of lead particles. From regression analysis, the concentrations of lead particles smaller than 1 um in AD were found to rise very slowly with increases in total PbA. They rarely contributed more than 50 ㎍/㎥ of total PbA over the range of 5.6-7,740 ㎍/㎥ although there are a few high values greater than 100 ㎍/㎥ while respirable lead concentrations significantly increased with increasing total PbA concentrations. In the secondary smelting and radiator manufacturing industries requiring high temperatures, the average fraction of respirable concentration in total PbA was 43.3% and 48.9%, respectively, which indicated an important contribution to the total PbA. In lead powder and battery manufacturing, it was less than 27%. Our study results concluded that workers' exposure to lead particles with diverse characteristics might not be effectively monitored by the current total PbA sampling alone. To protect workers exposed to different sizes of lead particles generated in many operations, an occupational standard for respirable lead particles should be added to the current total lead standard.

• 드라이브 ㆍ 컨트롤
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• 제12권2호
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• pp.21-26
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• 2015

In order to design a swash plate type pump for electro-hydrostatic actuators the performance of the hydrostatic piston shoe bearings in the low speed range needs to be examined, since the pump operates frequently at low speeds, compensating for position control errors as a control element. As a common practice, piston shoes are equipped with inner rings as an auxiliary element to enhance their tribological performance. In this paper, the effects of the inner rings of the piston shoes on the frictional loss and leakage flow rate were investigated, where three piston shoe models, with different inner ring shapes and different inlet orifice sizes, were integrated. The test results showed that a large inner ring and small inlet orifice were advantageous for reducing both the frictional loss and leakage flow rate; this could also be confirmed by computational analyses.

• Metals and materials international
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• 제24권6호
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• pp.1412-1421
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• 2018

Cold-expanded austenitic high nitrogen steel (HNS) was subjected to investigate the effects of grain size on the stress-controlled high cycle fatigue (HCF) as well as the strain-controlled low cycle fatigue (LCF) properties. The austenitic HNSs with two different grain sizes (160 and $292{\mu}m$) were fabricated by the different hot forging strain. The fine-grained (FG) specimen exhibited longer LCF life and higher HCF limit than those of the coarse-grained (CG) specimen. Fatigue crack growth testing showed that crack propagation rate in the FG specimen was the same as that in the CG specimen, implying that crack propagation rate did not affect the discrepancy of LCF life and HCF limit between two cold-expanded HNSs. Therefore, it was estimated that superior LCF and HCF properties in the FG specimen resulted from the retardation of the fatigue crack initiation as compared with the CG specimen. Transmission electron microscopy showed that the effective grain size including twin boundaries are much finer in the FG specimen than that in the CG specimen, which can give favorable contributions to strengthening.