• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2009.06a
• /
• pp.205-209
• /
• 2009

Recently, the increase of the size of GNP and the expansion of the foreign tour opportunities by the common 5 days work system in a week, reaction of the burden for visiting foreign countries, and expansion of airlines caused the rapid increase of overseas tour but slow increase in the number of foreign tourists, due to the price rise which might impact on the competitive power, and lack of tour infrastructure and attractiveness. As the wide area along the east coast of GyeongBuk Province has great amount of cultural, ocean and natural resources, it helps to get focused the tour industries and maximize the synergy effect through the mutual development coupling the resources and regions. On the basis of the potentials for the growth of east coast area to the international level and the development of local resources, a ocean tour and resort complex for four seasons, which has s strong connection to the local areas resulting the wide tour bond, could help to improve the local economy and balance the development of local province, and furthermore, jump to the level of the center in the East Coast area in the international society. Through the investigation and analysis of the ocean space development status and usage at the advanced foreign countries, the new meaning of the ocean space at the tour and resort complex would be proposed to the relevant local government in fit.

• Polymer(Korea)
• /
• v.24 no.3
• /
• pp.389-398
• /
• 2000

Transparent, abrasion resistant coatings with 4~13 ${\mu}{\textrm}{m}$ thickness were prepared by spin-coating on polycarbonates with organic/inorganic hybrid solutions, followed by UV curing and heat treatment at 12$0^{\circ}C$ for 12 hours. The coating solutions were composed of inorganic phase and organic phase in 0:100, 20:80, 30:70, 50:50, 80:20 wt% ratios, respectively, mixed with photoinitiator, senaitizer and surfactant. The inorganic phase was formed by sol-gel reaction of TEOS and silane coupling agent MPTMS in 1 : 2 or 2 : 1 molar ratios, the organic phase consisted of difunctional urethane acrylate oligomeric resin, multifunctional acrylate TMPTA and HDDA in 4 : 3 : 3 wt% ratio. The coating systems were investigated by FT-IR, $^{29}$ Si-NMR spectra. In addition, TGA/DSC for thermal analysis and SEM, AFM observation for coated surface were examined. Gererally, the homogeneity of phases, the surface smoothness of coating and abrasion resistance were improved with the higher content of inorganic component. Namely, coating system with below 10 $\AA$ surface roughness and T$_{g}$ of 15$0^{\circ}C$ showed only 10% decrease in light transmittance after abrasion test, whereas uncoated polycarbonate substrate exhibited 46% decrease..

• Journal of the Korean Vacuum Society
• /
• v.15 no.6
• /
• pp.587-593
• /
• 2006

The circuit of the EEFL system and the inverter has been analyzed into the resistance RL, the capacitance C of the EEFL-backlight system, and the inductance of transformer in the inverter. The lamp resistance and capacitance are deter-mined from the phase difference is between the lamp current and voltage and from the Q-V diagram, respectively. The single Lamp of EEFL for 32' LCD-BLU has the resistance of $66\;k\Omega$ and the capacitance of 21.61 pF. The resistance, which is connected by parallel in the 20-EEFLS BLU, is $3.3\;k\Omega$ and the capacitance is 402.1 pF. The matching frequency in the operation of lamp system is noted as $\omega_M=1/\sqrt{L_2C(1-k^2)}$, where $L_2$ is the inductance of secondary coil and k is the coupling coefficient between primary and secondary coil. The lamp current and voltage has maximum value at the matching frequency in the LCD BLU system. The results of analytic solutions are in good agreement with the experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.201-208
• /
• 2017

Recently, the installation of photovoltaic(PV) systems has been increasing due to the worldwide interest in eco-friendly and abundant solar energy. On the other hand, a PV system has approximately 25% power loss while the energy generated from solar cells is transformed to the power coupling point through a power conversion system (DC/AC). If the output voltage of a string in the PV system is lower than the operating range of the inverter when a part of module in the string has a shadow due to weather conditions, the string is not synchronized and the whole efficiency of output power in a PV system may be reduced significantly. Therefore, to overcome this problem, this paper proposes a novel control method to compensate for the lower voltage by introducing a DC/DC voltage regulator for each string in a PV system, which adopts a concept for MPPT (Maximum Power Point Tracking) control function using the P&O algorithm and adopts constant voltage control method used in an existing inverter. This paper also implements a 2kW DC/DC voltage regulator based on the proposed algorithm and performs a variety of scenario-based experiments. From the simulation result, it was confirmed that the operation efficiency in the proposed method is improved compared to the existing method.

• Experimental and Molecular Medicine
• /
• v.50 no.11
• /
• pp.3.1-3.11
• /
• 2018

This study aimed to verify the effects of estrogen on the onset and development of adolescent idiopathic scoliosis and the mechanisms associated with these effects by constructing a pubescent bipedal rat model. Experiments were conducted to investigate whether scoliosis progression was prevented by a Triptorelin treatment. One hundred twenty bipedal rats were divided into female, OVX (ovariectomy), OVX + E2, Triptorelin, sham, and male groups. According to a spinal radiographic analysis, the scoliosis rates and curve severity of the female and OVX + E2 groups were higher than those in the OVX, Triptorelin, and male groups. The measurements obtained from the sagittal plane of thoracic vertebrae CT confirmed a relatively slower growth of the anterior elements and a faster growth of the posterior elements between T11 and T13 in the female and OVX + E2 groups than in the OVX and Triptorelin groups. Histomorphometry and immunohistochemistry revealed a significantly longer hypertrophic zone of the vertebral cartilage growth plates that expressed more type X collagen and less type II collagen in the OVX and Triptorelin groups than in the female and OVX + E2 groups. Ki67 immunostaining confirmed an increase in the proliferation of vertebral growth plate chondrocytes in the OVX group compared with the female and OVX + E2 groups. In conclusion, estrogen obviously increased the incidence of scoliosis and curve severity in pubescent bipedal rats. The underlying mechanism may be a loss of coupling of the endochondral ossification between the anterior and posterior columns. Triptorelin decreased the incidence of scoliosis and curve magnitudes in bipedal female rats.

• The Journal of the Convergence on Culture Technology
• /
• v.5 no.4
• /
• pp.87-92
• /
• 2019

The purpose of this study is to investigate the preparation time of fire-fighting water for public fire hydrants and ground, underground fire hydrants. The equipment preparation time for stage 1 was 20.50 seconds for ground type and 24.67 seconds for underground type. The reason for this difference in preparation time is that an underground fire hydrant requires additional standpipes to connect to the main conduit of Paru and the underground hydrant, which open the manhole cover. Water tank Maintenance joint with water hose male coupling of the second stage was similar to that of the ground type of 48.50 seconds and underground water tipe of 49.00 seconds. This is because the operation of connecting the fire hose to the maintenance tank of the water tank car is the same. In the third stage, the water pipe connection was 43 seconds for ground type and 174.33 seconds for underground type. The reason why the time for connecting the water pipe to the fire hydrant is large difference is that the underground fire hydrant is opened by opening the manhole cover, After connecting the stand pipe to the fire hydrant, the additional process of connecting the water pipe to the stand pipe is required, which is considered to have greatly increased the time required. The opening of Water Control Valve and spindle Valve in the fourth stage was 66.50 seconds for the ground type and 78.83 seconds for the underground type. This difference is due to the fact that the spindle of the ground fire hydrant is located on the main body and can be easily opened, but the underground type is located next to the main body under the manhole and requires additional time to connect the opening equipment.

• Journal of Adhesion and Interface
• /
• v.22 no.3
• /
• pp.98-105
• /
• 2021

In this study, we prepared a silver nanoparticle transferable adhesive composition with transparency and adhesive properties using UV-curable urethane acrylate containing silane groups. The urethane-based adhesive composition was applied between the Ag/PET film in which silver nanoparticles were patterned on PET and the PC film to be transferred. Immediately after UV-curing with UV, PET was removed to complete the manufacture of Ag/PC film. UV-curable urethane acrylate containing silane groups was synthesized using polycaprolactone diol (PCL), isophrone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA), and (3-aminopropyl) triethoxysilane (APTES). The silane group of APTES can improve interfacial adhesion by reacting with the specially treated silver nanoparticle surface of the Ag/PET film. In addition, we improved the adhesion between silver nanoparticle and PC film by mixing UV-curable urethane acrylate containing a silane group and a functional acrylic diluent used as a diluent. We analyzed the synthesis process of urethane acrylate using FT-IR, and compared the adhesive properties, optical properties, and transfer properties according to the molar ratio of APTES and the acrylic diluent composition. As a result, the best transfer properties were confirmed in the adhesive composition prepared under the conditions of PUA2S1_0.5.

• Journal of Adhesion and Interface
• /
• v.22 no.4
• /
• pp.136-143
• /
• 2021

Polyurea has been investigated as a polymer matrix for composite materials because of its high mechanical strength. Although polyurea has a similar chemical structure to polyurethane, it has much higher strength and durability. In this study, the fabrication of polyurea composites reinforced with carbon nanotube (CNT) and graphene oxide (GO) is demonstrated to enhance the tensile strength of the glass fibers composite. Using FTIR and Raman spectroscopies, the chemical structures of polyurea, CNT, and GO are investigated. As a result, spectroscopy analysis reveals that the chemical structure of CNT, GO, and polyurea is maintained during the fabrication of the composite structure. Scanning electron microscopy reveals the uniform distribution of CNT and GO across the polyurea matrix. The reinforcement of 1 wt% CNT in polyurea enhances the tensile strength of CNT/polyurea composites. In contrast, the reinforcement of GO in polyurea induces the degradation of the tensile strength of GO/polyurea composites.

• Tunnel and Underground Space
• /
• v.29 no.3
• /
• pp.197-213
• /
• 2019

We simulated the fault reactivation experiment conducted at 'Main Fault' intersecting the low permeability clay formations of Mont Terri Underground Research Laboratory in Switzerland using TOUGH-FLAC simulator. The fluid flow along a fault was modelled with solid elements and governed by Darcy's law with the cubic law in TOUGH2, whereas the mechanical behavior of a single fault was represented by creating interface elements between two separating rock blocks in FLAC3D. We formulate the hydro-mechanical coupling relation of hydraulic aperture to consider the elastic fracture opening and failure-induced dilation for reproducing the abrupt changes in injection flow rate and monitoring pressure at fracture opening pressure. A parametric study was conducted to examine the effects of in-situ stress condition and fault deformation and strength parameters and to find the optimal parameter set to reproduce the field observations. In the best matching simulation, the fracture opening pressure and variations of injection flow rate and monitoring pressure showed good agreement with field experiment results, which suggests the capability of the numerical model to reasonably capture the fracture opening and propagation process. The model overestimated the fault displacement in shear direction and the range of reactivated zone, which was attributed to the progressive shear failures along the fault at high injection pressure. In the field experiment results, however, fracture tensile opening seems the dominant mechanism affecting the hydraulic aperture increase.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.3
• /
• pp.202-208
• /
• 2019

In this study, an active element pattern (AEP) of a printed dipole was analyzed in 1D and 2D arrays. First, an AEP of the printed dipole was obtained using the simulation in the 2D infinite array. The scan blindness in the 2D array occurred in the E-plane direction at around ${\pm}36^{\circ}$; however, it was barely observed in the 1D array. To analyze the cause of the scan blindness in the 2D array, the dispersion properties of a unit cell was obtained and compared with the scan blindness by frequency change. The difference between the scan blindness of the 1D and 2D arrays was clarified using the comparison of the Q value in the unit cell in the 1D and 2D arrays. Then, the coupling of the electric field in the E-plane direction was observed when nine elements were separated between the two ports in a linearly arranged dipole structure. Finally, the printed dipole array was fabricated, and an AEP was measured for the $11{\times}1$ and $11{\times}3$ sub arrays. The proposed theory was verified using these observations and by comparison with the simulation results.