• Journal of the Society of Naval Architects of Korea
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• v.49 no.3
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• pp.227-231
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• 2012

In this study, a plastic hardening constitutive equation for steels of polar class vessels at low temperature is proposed. The equation was derived using the experimental data obtained from tensile tests at room and low temperatures. Tensile tests at low temperature are both costly and time consuming because an expensive cold chamber is necessary and it takes too much time to cool down a specimen to set temperature. Using the proposed plastic hardening constitutive equation the plastic hardening characteristics of steels for polar class vessels at low temperature can be easily predicted from the tensile test results at room temperature.

• Korean Journal of Adult Nursing
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• v.22 no.5
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• pp.529-536
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• 2010

Purpose: This study was designed to identify the effect of auriculotherapy on low abdominal pain and dysmenorrhea in school-aged girls. Methods: This design was a pre and post-test with nonequivalent groups. The subjects were 71 girls who were middle school students with dysmenorrheal (35 students for the treatment group and 36 students for the comparison group). The subjects of the treatment group received auriculotherapy once a week for 10 weeks. The comparison group received instruction on auriculotherapy and was requested waiting for the order. Results: The treatment group reported significantly less low abdominal pain than the comparison group. However, there were not statistical differences in reported dysmenorrhea. In future analysis, 60.0% of the treatment group reported more physical comfort, and 45.7% reported more emotional cool down. Conclusion: The finding indicate that auriculotherapy could be effective in decreasing low abdominal pain during menstrual periods. Therefore, auriculotherapy could be an effective nursing intervention for low abdominal pain occurring during mensuration. However, further studies need to be done to support auriculotherapy as effective.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1472-1482
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• 2017

Zirconium alloy cladding tube specimens were irradiated at $380^{\circ}C$ up to a fast neutron fluence of $7.5{\times}10^{24}n/m^2$ in a research reactor to investigate the effect of neutron irradiation on hydride reorientation and mechanical property degradation. Cool-down tests from $400^{\circ}C$ to $200^{\circ}C$ under 150 MPa tensile hoop stress were performed. These tests indicate that the irradiated specimens generated a smaller radial hydride fraction than did the unirradiated specimens and that higher hydrogen content generated a smaller radial hydride fraction. The irradiated specimens of 500 ppm-H showed smaller ultimate tensile strength and plastic strain than those characteristics of the 250 ppm-H specimens. This mechanical property degradation caused by neutron irradiation can be explained by tensile hoop stress-induced microcrack formation on the hydrides in the irradiation-damaged matrix and subsequent microcrack propagation along the hydrides and/or through the matrix.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.77-81
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• 2002

The helium recondensing type cryostat with 4 K GM cryocooler is fabricated in order to keep cryogenic state of two saddle type superconducting magnet opposite to each other designed maximum 0.3 T magnetic field, and 1270 mm diameter open bore. The current leads which consist of metal current leads made for brass sheet and HTS current leads made in American Superconductor$^{TM}$ intermediate cool down with cryocooler Thus , the cryocooler for helium recondensing is a 1.5W/4.2 K GM SUMITOMO cryocooler. While superconducting magnet is working of 1600 gauss to 200 A, the cryostat keep constantly the level of liquid helium at 0.05 bar gauge pressure.e.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1312-1316
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• 2004

The Stirling refrigerators have been widely used for the cooling of the infrared detector and HTS to the cryogenic temperature. The Stirling refrigerator with the rotary compressor are applicable to the cooling device for the compact mobile thermal imaging system, because the refrigerators have the compact structure and light weight. The typical performance factors of the Stirling refrigerator are the cool-down time, cooling capacity at the desired temperature and the input power. And the above performance factors are depends on the thermal insulation characteristics of the Dewar. In this study, the steady thermal load of the Dewar and the performance of the Stirling refrigerator were measured. The results show the dependency of the input power and the charging pressure on the performance of the refrigerator.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.14 no.1
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• pp.111-116
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• 2001

Nummular eczema is well-shaped, coin-like lesion. Usually it is surrounded by the papules and vesicles, and is likely to be the impetigo. It's said that nummular eczema is combined with atopic dermititis, contact dermatitis, bacterial infection and so on. Recently, we experienced a nummular eczema with impetigo and that was successfully treated by the herb-medication and the ceramic resonance therapy. The medications taken by the patient were yunwhasagnatang and gamisopungsan which is used to treat allergic disease and make immune system be strong. The former effects the liver to be cool down and healthy and it also has anti-imflamatory reactions like the corticosteroid hormone. Ceramic resonance therapy utilises irradiation within the frequency range of the radiation emitted by the human body. So we report this case with a brief review of the oriental medical and medical literatures.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1972-1977
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• 2011

The mechanical integrity of generator stator windings is one of the critical point because the electric power is generated and conducted to power system through these windings. To cool down the heat emitted from generator winding during its operation, a majority of generators use de-mineralized water characterized by high cooling efficiency. Contrary to such the excellent cooling efficiency, however, the damaged bar insulations attributed to the absorption of cooling water in the generator stator winding lead to highly time- and cost consuming efforts as well as to service deterioration due to unexpected forced outage of generator. It is described that the new design of water absorption sensor using cross capacitance for generator in power plant in order to increase the reliability of water absorption diagnostics for generator stator bar insulation.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1486-1494
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• 2020

To evaluate transport-induced cladding embrittlement after interim-dry storage, ring compression tests were carried out at room temperature(RT) and 135 ℃. The ring compression test specimens were prepared by simulating the interim-dry storage conditions that include four peak cladding temperatures of 250, 300, 350 and 400 ℃, two tensile hoop stresses of 80 and 100 MPa, two hydrogen contents of 250 and 500 wt.ppm-H and a cooling rate of 0.3 ℃/min. Radial hydride fractions of the ring specimens vary depending on those interim-dry storage conditions. The RT compression tests generated lower offset strains than the 135 ℃ ones. In addition, the RT and 135 ℃ compression tests indicate that a higher peak cladding temperature, a higher tensile hoop stress and the lower hydrogen content generated a lower offset strain. Based on the embrittlement criterion of 2.0% offset strain, an allowable peak temperature during the interim-dry storage may be proposed to be less than 350 ℃ under the tensile hoop stress of 80 MPa at the terminal cool-down temperature of 135 ℃.

• Particle and aerosol research
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• v.10 no.3
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• pp.93-97
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• 2014

Condensation particle counter (CPC) has been one of the most important basic instrument for measuring number concentration of submicron aerosols. The principle of the CPC is to expose aerosols to a supersaturated vapor and cool down which causes adiabatic expansion. The particles grow by heterogenous nucleation to a sufficient size for easy detection by optical method. However, for growth by condensation, CPC essentially needs both saturater and condensor causing a heavy system. Therefore, it is hard to install commercial CPC to tethered balloon package system. In this study, we developed customized CPC for tethered balloon package system called Hy-CPC which is lighter and smaller in structure than commercial CPCs, and evaluated activation efficiency and detection efficiency by Hy-CPC using electrostatic method (electrometer and Faraday cup).

• 연구논문집
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• s.29
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• pp.17-27
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• 1999

The experimental results of the 17K inertance tube pulse tube cryocooler for cooling cryosensors are presented in this paper. In prototype experiments, linear compressor is driven by linear motor, and inertance tubes are inserted between one liter reservoir and pulse tube. Design of the inertance tube pulse tube cryo-cooler is conducted by ARCOPTR program of NASA Ames Research Center. To find optimal conditions of inertance tube pulse tube cryocooler, no load temperature and refrigeration capacity according to the variations of inertance tube volume, reservoir volume and charging pressure are measured. and the cool down and load characteristics at the particular conditions are presented. As the representative results, no load temperature of the cold end is 52.7K and refrigeration capacity is 5W at 72K..