• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.215-216
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• 2016

Urethane waterproofing materials which currently being used most commonly in the Korean domestic market have high applicability and construct layers without forming any joints, but under the influence of low temperature and low humidity, as well as the thickness of the applied layer, the curing time of this material may become extended in construction sites. To resolve these issues, a proposed method of using water-hardening type of polyurethane waterproofing materials are being developed. However, there currently lacks any standards or evaluation methods on determining an optimal mixture ratio of water for the water-hardening polyurethane waterproofing materials. Therefore, for the establishment of a board applicability of the water-hardening polyurethane waterproofing methods in construction sites, this study objectively analyzes the changes in the performance of these materials depending on the changes of the water mixture ratio and attempts to procure the optimal ratio on the basis of forming a provisionary standard.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.4
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• pp.7-13
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• 2015

The efficiency, reliability and performance of any heat pump unit can only be ascertained after it has been tested and rated. For this reason, specific facilities, equiped with testing plants are built. Heat pump calorimeter is the facilities used by most of these testing facilities in their rating and certification process. The ultimate function of calorimeters is to, control and maintain the constant standard test conditions (indoor/outdoor entering temperatures and flow rate etc) during testing period. In this study, the test standards of heat pump unit and the structure of the calorimeter are surveyed. In addition, this study analyzes the total energy consumption of a water to water heat pump calorimeter. Heat pump calorimeter consumed much energy to excute the heat pump tests. The energy consumption of the calorimeter was higher than the heat pump unit, and it was increased as the heat pump unit capacity decreased.

• Journal of Magnetics
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• v.12 no.4
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• pp.144-148
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• 2007

We report on the observation of p-type conductivity and ferromagnetism in diluted magnetic semiconductor $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films grown on $SiO_2/Si$ substrates by pulsed laser deposition. The p-type conduction with hole concentration over $10^{18}cm^{-3}$ is obtained by codoping of Mg and P followed by rapid thermal annealing in an $O_2$ atmosphere. Structural and compositional analyses for the p-type $(Zn_{0.97}Mg_{0.01}Mn_{0.02})O:P$ films annealed at $800^{\circ}C$ indicates that highly c-axis oriented homogeneous films were grown without any detectable formation of secondary phases. The films were found to be transparent in the visible range. The magnetic measurements clearly revealed an enhancement of room temperature ferromagnetism by p-type doping.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1167-1171
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• 2008

The flow and thermal performance of the skiving and louver fin type heat sinks for the cooling system of the small LED projector were experimentally evaluated. A small fan tester based on AMCA standards was used to control and measure the air flow rate into the heat sink. Three heat blocks were used to simulate the heat and light sources(red, green and blue) of the small LED projector. We measured the pressure drop, temperatures and input power at the specific air flow rate and discussed those results. As a result, it is found that the louver fin type heat sink has higher pressure drop and lower thermal resistance than the skiving type. From the comparison of the temperature of the heat block between skiving and louver fin type, the louver fin type heat sink was found to be more suitable for cooling the high power heat source than skiving type. The thermal performance of the fan-sink(louver fin type) system was discussed with the picture taken by a thermal video.

• Bulletin of the Korean Chemical Society
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• v.24 no.3
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• pp.345-349
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• 2003

The quantity, process and kinetics of di-(2-ethylhexyl)phthalate (DEHP) migration in the 30/70 and 40/60 poly(vinylchloride) (PVC)/DEHP blends were investigated using gas chromatograph. A thin and flexible PVC sheet was soaked in surrounding medium (SM) of water/ethanol mixture and acetonitrile with constant stirring to release DEHP. By observed concentration of DEHP in the SM, it is found that acetonitrile is more intense in DEHP migration than water/ethanol mixture. In addition the amount of extracted DEHP is proportional to the leaching temperature and added ratio of DEHP. The behavior of DEHP migration from flexible PVC sheets was described by the Ficks's law with $2.72-10.1\;{times}\;10^{-10}$ cm²/s of the diffusion coefficients.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.893-905
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• 2016

Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.

• Korean Journal of Materials Research
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• v.12 no.3
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• pp.195-199
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• 2002

Planar Hall effect of ferromagnetic GaMnAs thin films was investigated for the first time. The films were grown in an optimized growth condition via molecular beam epitaxy at low temperatures. For the optimization of the growth conditions, we used reflection high-energy electron diffraction, electrical conductivity, double crystal x-ray diffraction, and superconducting quantum interference device measurements techniques. We observed that the difference between the longitudinal resistance and the transverse resistance matches the planar Hall resistance. The ratio of the planar Hall resistance at saturation magnetic field to that at zero reached above 500%.

• Korean Journal of Materials Research
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• v.18 no.8
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• pp.444-449
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• 2008

Samples of GaMnAs, GaMnAs codoped with Be, and GaMnAs simultaneously codoped with Be and Mg were grown via low-temperature molecular beam epitaxy (LT-MBE). Be codoping is shown to take the Ga sites into the lattice efficiently and to increase the conductivity of GaMnAs. Additionally, it shifts the semiconducting behavior of GaMnAs to metallic while the Mn concentration in the GaMnAs solid solution is reduced. However, with simultaneous codoping of GaMnAs with Be and Mg, the Mn concentration increases dramatically several times over that in a GaMnAs sample alone. Mg and Be are shown to eject Mn from the Ga sites to form MnAs and MnGa precipitates.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.17-24
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• 1997

We have developed a patient monitoring system including module-based bedside monitors, interbed network, central stations, clinical workstations, and DB servers. A bedside monitor with a color LCD can accommodate up to 3 module cases and 21 different modules. Six different physiological parameters of ECG, respiration, invasive blood pressure, noninvasive blood pressure, body temperature, and arterial pulse oximetry with plethysmoyaph are provided as parameter modules. In a single bedside monitor, modules and a module controller communicate with IMbps data rate through an intrabed network based on RS-485 and HDU protocol. At the same time, it communicates with other bedside monitors and central stations through interbed network based on 1 OMbps Ethernet and TCP/IP protocol. Central stations using 20" color CRT monitors can be connected with many bedside monitors and they display 18 channels of waveforms simultaneously. Clinical workstations are used mainly for the review of patient datE In order to accommodate more advanced data management capabilities such as 24-hour full disclosure, we have developed a relational database server dedicated to the patient monitoring system. Software for bedside monitor, central station, and clinical workstation fully utilizes graphical user interface techniques and all functions are controlled by a rotate/push button on the bedside monitor arid a mouse on the central station and clinical workstation. The entire system satisfies the requirements of AAMI and ANSI standards in terms of electrical safety and performances.nces.

• Journal of the Korean Applied Science and Technology
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• v.18 no.4
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• pp.261-272
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• 2001

An ACR/HMMM film was prepared by blending high-solid ACR with curing agent, hexamethoxymethyl melamine (HMMM). An active curing reaction was observed at $170^{\circ}C$. The dynamic viscoelastic $T_{g}$ of the final film increased with the static viscoelastic $T_{g}$ of the film. The log damp value, which means a viscoelastic ratio, decreased with the increase in the curing temperature of the film. Physical properties of the films were within a suitable range for films, and by an accelerated weathering resistance test the films were proved weather resistible ones.