• Corrosion Science and Technology
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• v.7 no.1
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• pp.1-5
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• 2008

The gas atmosphere in continuous annealing and galvanizing lines alters both composition and microstructure of the surface and sub-surface of sheet steel. The formation and morphology of the oxides of alloying elements in High Strength Interstitial Free (HS-IF), Dual Phase (DP) and Transformation-Induced Plasticity (TRIP) steels are strongly influenced by the furnace dew point, and the presence of specific oxide may result in surface defects and bare areas on galvanized sheet products. The present contribution reviews the progress made recently in understanding the selective formation of surface and subsurface oxides during annealing in hot dip galvanizing and conventional continuous annealing lines. It is believed that the surface and sub-surface composition and microstructure have a pronounced influence on galvanized sheet product surface quality. In the present study, it is shown that the understanding of the relevant phenomena requires a combination of precise laboratory-scale simulations of the relevant technological processes and the use of advanced surface analytical tools.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.169-177
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• 2018

Twisted rudder, twisted rudder with bulb, and twisted rudder with bulb and fin have been developed computationally for 3,000 TEU container ship through parametric study. The objective function is to minimize delivered power in model scale. Design variables are twisted angle, rudder bulb diameter and fin angle. The governing equation is Reynolds averaged Navier-Stokes equations in an unsteady turbulent flow and the Reynolds stress model applied for the turbulent closure. A double body model is used for the treatment of free-surface. The calculation was carried out in towing and self-propulsion conditions at design speed. The sliding mesh technique was employed to simulate the flow around the propeller. Form factor is obtained from the towing computation. Self-propulsion point is obtained from the self-propelled computations at two propeller rotating speeds. The delivered power due to the designed twisted rudder, twisted rudder with bulb, and twisted rudder with bulb and fin are reduced by 1.1%, 1.6%, and 2.0%, respectively.

• Journal of Welding and Joining
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• v.29 no.5
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• pp.95-98
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• 2011

Recently, there is a growing tendency that fine-pitch electronic devices are increased due to higher density and very large scale integration. Finer pitch printed circuit board(PCB) is to be decrease insulation resistance between circuit patterns and electrical components, which will induce to electrical short in electronic circuit by electrochemical migration when it exposes to long term in high temperature and high humidity. In this research, the effect of soldering flux acting as an electrical carrier between conductors on electrochemical migration was investigated. The PCB pad was coated with OSP finish. Sn3.0Ag0.5Cu solder paste was printed on the PCB circuit and then the coupon was treated by reflow process. Thereby, specimen for ion migration test was fabricated. Electrochemical migration test was conducted under the condition of DC 48 V, $85^{\circ}C$, and 85 % relative humidity. Their life time could be increased about 22% by means of removal of flux. The fundamentals and mechanism of electrochemical migration was discussed depending on the existence of flux residues after reflow process.

• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.195-200
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• 2005

This study optimized the mixing ratios of seafood sauce with blue crab for maximal sensory attributes using a response surface methodology with central composite design. It evaluated sensory appeal, nutritional value, and some rheological properties. The optimal formulation appeared to be 252 g of tomato paste, 78 g of chopped garlic, and 519 g of blue crab block; this ratio resulted in a predicted sensory score of 5.7 (on a 7-point scale) for overall acceptability. Addition of blue crab block increased moisture, ash, and protein contents in various sauces, but fat contents were similar in every sauce. Major free amino acids such as glutamic acid, phospho serine, asparagine, and arginine composed about $60\%$ of the total amino acid content. Standard and optimized sauces were red and light yellow, and those color values were significantly higher than in American-style sauces. Optimal viscosity was half the value of American-style sauces; more blue crab block added to the sauce resulted in lower viscosity. Adding this sauce to seafood dishes will likely aid development of flavoring substances.

• Journal of the Korean institute of surface engineering
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• v.35 no.1
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• pp.17-32
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• 2002

Electroplating methods by molten salts and non-aqueous melts were employed for aluminium coating on STS 316L stainless steel. After coated with Ni or non-coated surface on stainless steel, Al pulse plating was carried out in two different types of electrolytes at room temperature. The Al layer from $AlCl_3$-TMPAC melts could not obtain appreciable thickness for engineering application due to chemical reactions between deposits and moisture of air. However, The Al coating by pulse plating in the Ethylbenzene-Toluene-$AlBr_3$ systems was found to be solid coating layer with a few $\mu\textrm{m}$ scale. The conductivity of Ethylbenzene-Toluene-$AlBr_3$ electrolyte was as functions of time and agitation. By seven days exposure after mixing of the electrolyte, Al-deposited layer shows uniform and near by pore-free with high current density (higher than 30mA/$\textrm{cm}^2$). The roughness and imperfection of coating layer were decreased with a increasing agitation speed. It was found that the optimum condition for the Al pulse plating on the 316L stainless steel was a 400mA peak current, duty cycle, $t_{on}$ $t_{ off}$=3ms/1ms, and a current density of 30mA/$\textrm{cm}^2$.

• Journal of Korean Foot and Ankle Society
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• v.20 no.4
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• pp.170-175
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• 2016

Purpose: The aim of this study is to evaluate the effectiveness of surgical treatment in adolescent patients suffering from navicular stress fracture. Materials and Methods: A total of 11 adolescent patients aged 14 to 19, who underwent an operation for navicular stress fracture between 2005 and 2008 were recruited. Clinical outcomes were evaluated by the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score and visual analogue scale (VAS) score. Results: The mean VAS score before the operation was 7.7. A score of 2.9 was confirmed at final follow up after the operation. The mean final follow-up period was 22.1 months. There was a statistically significant improvement in the VAS score between before and after the operation (p=0.01), and similarly, the AOFAS score also showed an improvement, from 46.5 to 80.7 (p=0.01). The pain that remained after the operation, according to the VAS score, was severe in three patients (27.3%), tolerable in seven patients (63.6%), and free of pain in one patient (9.1%). Conclusion: In navicular stress fracture in adolescents, careful selection of patients who could benefit from surgical treatment is recommended.

• Journal of Families and Better Life
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• v.19 no.6
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• pp.113-128
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• 2001

middle and upper class families, and examine obstacles to their introduction in Korea. Since a few large-scale facilities for the elderly with dementia have been provided for only low-income families free of charge, the necessity of group homes for middle and upper class families willing to pay for such services has become an issue recently in order to lessen the burden on families, as well as to promote the well-being of the dementia victims themselves. The survey was conducted by questionnaires collected from 577 respondents from middle and upper class families. The results of the survey were as follows: The merits of the group homes were 1)decreasing loneliness of the elderly, 2)providing active and stimulating environments allowing for participation everyday life activities, and 3)lessening the emotional and physical burden on the caring families. Potential obstacles to its introduction in Korea were 1)the difficulty of finding sites to build the group home because of the negative perception of people with disabilities and a NIMBY(Not In My Back Yard) reaction to the construction of it and 2)the economic burden on the caring family. Surprisingly, the guilt factor associated with sending the parents into group homes was not considered as a big obstacle. Referring to results of this study, it is asserted that group homes for the elderly with dementia would be embraced throughout the country if Koreans could have the chance to understand what group homes are.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.355-358
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• 2010

As CMOS technology continues to scale down, signal processing is favorably done in the digital domain, which requires Analog-to-Digital (A/D) Converter to be integrated on-chip. This paper presents a design methodology of 12-bit 1-MS/s Rail-to-Rail fully differential SAR ADC using Deep N-well Switch based on binary search algorithm. Proposed A/D Converter has the following architecture and techniques. Firstly, chip size and power consumption is reduced due to split capacitor array architecture and charge recycling method. Secondly, fully differential architecture is used to reduce noise between the digital part and converters. Finally, to reduce the mismatch effect and noise error, the circuit is designed to be available for Rail-to-Rail input range using simple Deep N-well switch. The A/D Converter fabricated in a TSMC 0.18um 1P6M CMOS technology and has a Signal-to-Noise-and-Distortion-Ratio(SNDR) of 69 dB and Free-Dynamic-Range (SFDR) of 73 dB. The occupied active area is $0.6mm^2$.

• The Journal of Fisheries Business Administration
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• v.39 no.3
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• pp.49-65
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• 2008

In Korea, deep-sea fishing industry is faced with pressure of being thrown out of business, because of the upcoming unfavorable business conditions such as the fishing regulation of coastal countries, Korea-US Free Trade Agreement(KORUS FTA), and the other socio-economic changes. Hence, we present an evaluation of future business competitive for the deep-sea fishing industry so that the government can develop a concession plan for the deep-sea fishing industry by utilizing the results of this study. In efficiency analysis of deep-sea fishing industry, the decision maker may have two problems: (1) how to deal with multiple inputs and outputs of deep-sea fishing industry and (2) how to assign the weights on different inputs and outputs, In this paper, we proposed to use Data Envelopment Analysis (DEA) to estimate efficiency of deep-sea fishing industry with multiple inputs and outputs. In the DEA, The direct impact of KORUS FTA, fishing regulation of coastal countries, fishing charges, and competitive fishing conditions were used as input parameters while the profitability and secured fishing quarters, as outputs. The results of DEA-BCC model indicate that 6 out of 12 DUMs have better efficiency under variable return to scale assumption.

• 한국전산유체공학회:학술대회논문집
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• 2002.05a
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• pp.8-15
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• 2002

For the large scale computation of turbulent flows around an arbitrarily shaped body, a parallel LES (large eddy simulation) code has been recently developed in which domain decomposition method is adopted. METIS and MPI (message Passing interface) libraries are used for domain partitioning and data communication between processors, respectively. For unsteady computation of the incompressible Wavier-Stokes equation, 4-step splitting finite element algorithm [1] is adopted and Smagorinsky or dynamic LES model can be chosen fur the modeling of small eddies in turbulent flows. For the validation and performance-estimation of the parallel code, a three-dimensional laminar flow generated by natural convection inside a cube has been solved. Then, we have solved the turbulent flow around MIRA (Motor Industry Research Association) model at $Re = 2.6\times10^6$, which is based on the model height and inlet free stream velocity, using 32 processors on IBM SMP cluster and compared with the existing experiment.