• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.114-119
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• 2004

For passenger vessels, twin shaft types in propulsion system is generally adopted to provide a high-speed performance in low draught due to restricted operating condition in harbors or water channels. Struts of twin open shaft type support the shafts, bearings, and propellers. Therefore, strut design is needed to consider not only hydrodynamic performance but also structural and noise/vibration performance, In this paper, considerations in strut design at the initial design stage have been discussed based on existing references, numerical calculations, and their comparisons. Also, the strut design of a RoPax ferry has been carried out at the initial design stage, for an example.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.407-414
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• 2011

We analyze the cooperative spontaneous emission of optically excited nanocrystals into surface plasmon polaritons propagating on the surface of a cylindrical metallic nanowire. The spontaneous emission probability of the nanocrystals is obtained by perturbative expansions with and without dipole-dipole interaction among nanocrystals in order to see the cooperative effects. The spontaneous emission probability depends on the radial and axial distributions, as well as on the dipolar orientation of nanocrystals. It is shown that the spontaneous emission probability is strongly influenced by dipole-dipole interaction, axial distribution, and dipolar orientation of nanocrystals for closely spaced nanocrystals.

• Journal of Environmental Science International
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• v.26 no.2
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• pp.265-268
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• 2017

The objective of this study was to evaluate the characteristics of duck litter in ducks fed diets containing Houttuynia cordata powder. One-day-old ducklings (Pekin) were randomly divided into two groups and fed a control or 1% H. cordata powder-containing diet for an experimental period of three weeks. The results showed that pH for 1-2 weeks and total nitrogen for 1-3 weeks in duck litter were affected by dietary treatments with 1% H. cordata powder (P < 0.05). For Volatile Fatty Acids (VFAs), there was no significant difference (P > 0.05) between ducks fed 1% H. cordata and control diets, as shown in the results for acetic acid and propionic acid in duck litter over three weeks; but, this was not the case for propionic acid at 3 weeks. The inclusion of 1% H. cordata powder in the diet had a the positive effect on increasing the total nitrogen and decreasing pH and VFAs in duck litter.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.341-344
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• 2018

This study was conducted to determine the effects of dietary bentonite supplementation on the fatty acid profiles of eggs in older laying hens. A total of 90 Hy-line Brown layers, 74 weeks of age, were confined in 6 wire cages and then assigned randomly to two groups to receive one of the two diets (3 replicates of 15 older layers each) containing 0 and 0.2% bentonite for 4 weeks. After the 4-week feeding trial, no remarkable differences in individual fatty acid, saturated fatty acid (SFA), unsaturated fatty acid (UFA), and mono unsaturated fatty acid (MUFA) levels were found. However, linoleic acid, docosahexaenoic acid, and poly unsaturated fatty acid (PUFA) and UFA/SFA ratio were influenced by 0.2% bentonite. In conclusion, supplementation with 0.2% bentonite improved the profiles of PUFA more than those of SFA, UFA, and MUFA inthe eggs of the older laying hens.

• Bulletin of the Korean Chemical Society
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• v.24 no.2
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• pp.239-242
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• 2003

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.201-205
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• 2009

We investigated the optimum adhesive thickness for athermalizing an elastomeric lens mount in our space optics application. Theoretical results were compared with finite element solutions using two different models; discrete circular pads and discrete circular pads with columns filling the insertion holes reflecting the reality. A noticeable difference between their optimal thicknesses was observed, and physical interpretation revealed the uncertainty of prevailing athermal equations. A pilot sample was made to check our results and thermo-optical stress was assessed using an interferometer after isothermal load. This study presented insight into preliminary design guidance in elastomeric lens mounting.

• Transactions of Materials Processing
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• v.15 no.8 s.89
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• pp.568-573
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• 2006

In order to numerically evaluate automotive hydro-formed DP-steel tubes on crash performance considering welding heat effects, the finite element simulations of crash behavior were performed for hydro-formed tubes with and without heat treatment effects. This work involves the mechanical characterization of the base material and the HAG-welded zone as well as finite element simulations of the crash test of hydro-formed tubes with welded brackets and hydro-forming of tubes. The welding heat effects on the crash performance are evaluated in efforts to improve the process optimization procedure of the engine cradle in the design stage. In particular, FEM simulations on indentations have been performed and experimentally verified for material properties of weld zone and heat affected zone.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1960-1962
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• 1996

A thermopneumatic micropump with two micronozzles has been fabricated and tested. The actuator consists of a p+ diaphragm and a pyrex glass on which a microheater is deposited. Two micronozzles are fabricated on either side of a single silicon wafer and behave as a dynamic passive valves. The actuator and the micronozzle are assembled to make a micropump. The center deflection of the actuator diaphragm to step voltage input has been measured. The dynamic test hag been performed by measuring the center deflection of the diaphragm under various input voltages and duty ratios. Also dynamic pumping test is performed. The measured built-up pressure between inlet and outlet of the micropump is 80 Pa for the actuation at 20V, 10 Hz.

• International Commerce and Information Review
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• v.10 no.3
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• pp.333-351
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• 2008

This study shows a comprehensive survey of literatures in international trades in services. It is true that most research works in international trade have been focusing on commodity trades but relatively not many works have been done on international services trade study. This paper discusses a research framework of international services in trades research and suggests some recommendations for future research. The study shows that most of the research works so far have been at initial stage of maturity and as a result not many strategic types of studies are not reported in this field. The main reason is that the research methodology for international trades in services is weak though the opportunity being large. Therefore, future research has to be made to enhance the research methodology study in the international trades in services.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.129-134
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• 2012

In this paper, a new simple PWM method for Vienna rectifier is proposed. The previous SVPWM method for Vienna rectifier is very complex and difficult to implement. To solve these problems, a new single-carrier comparison PWM method for voltage control of Vienna rectifier is proposed. Because of using the only single carrier, implementation of the proposed PWM is very simple. In the proposed PWM method, carrier comparison parts of the PWM block is only changed from the 2 level PWM control block. The usefulness of the proposed PWM method is verified by the simulation and experiment.