• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1564-1569
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• 2004

Insulating a heat from the environment is the most important in cryogenic applications like HTS cable system. Vacuum and MLI(Multi-Layer Insulation) have been widely used to get highly efficient cryogenic insulation. In this study, experiment on annular cylinder regarded as basic model of HTS cable cryostat has been performed to measure the heat loads. To investigate the effectiveness of radiation shields in cryogenic insulation system, the experiments are carried out to various number of the shields. The measured values are compared with the results estimated theoretically. The heat loads invaded from the environment was determined by liquid nitrogen boil-off calorimetry.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.395-400
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• 2002

Epoxy coating and sealing used in nuclear plants for the protection of radiation degrades with aging and hazardous atmosphere. In order to evaluate the degradation of the epoxy, dependence of the acoustic impedance on the change of mechanical properties has been used. Unlike metals, the surface of the epoxy coating on a concrete liner is so wavy that the acoustic impedance is difficult to measure by using the reflectivity of the ultrasound on the interface surface because of the irregular reflection and propagation from the epoxy surface. SA(simulated annealing) algorithm is applied to calculate the acoustic impedance using a reflection wave from the rough epoxy surface. The surface waviness and acoustic impedance are taken into account and determined by SA method to evaluate the state of degradation quantitatively.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.320-323
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• 2009

Weather data is an important variable for the estimation value of the program for evaluating energy performance. The difference in data value of major weather elements used in weather data (temperature, insolation amount) were compared and analyzed. It was found that temperature showed similar values but insolation amount took different values. Especially in Ulsan, since the Meteorological Association does not measure insolation amount. To optimize the incident solar radiation, the solar azimuth angles are needed for solar photovoltaic systems. Test results shows that the $60^{\circ}$installation angel higher efficient than the $30^{\circ}$ installation angel in winter.

• Korean Journal of Materials Research
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• v.6 no.6
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• pp.576-584
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• 1996

The zirconia-alumina composite, a low loss material, was sucessfully sintered using a 2.45 GHz microwave radiation. The dense zirconia was used as a microware coupling aid. The effect of microwave power level on the heating rates of samples and the feasibility of microwave energy use in processign ceramec materials were obtained. It was also obtained how to accurately measure the temperature. According to the microwave heating theory, heating mechanisms were discussed.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.43-46
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• 2005

A Protomodel Space Infrared Cryogenic System (PSICS) cooled by a stirling cryocooler was designed. The PSICS has an IR sensor inside a cold box which is cooled by a stilting cryocooler with refrigeration capacity of 500mw at 80K in a vacuum vessel. It is important to minimize heat load for reducing background thermal noise. In order to design the cryogenic system of low heat load and to reduce heat load, we did several numerical analyses and tested using boil-off calorimetry with liquid nitrogen to measure the heat leak of the system. In this paper, we present the results obtained by thermal analysis and heat load measurement for designing the PSICS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1111-1117
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• 1999

In order to measure the temperature of bridge wire, the explosive material is removed from EED and a fiber optic temperature sensor is installed near the bridge wire. Using the heat transfer theory, the optimum position of the fiber optic sensor in the EED is determined and the temperature-distance equation is derived from test result. The measuring technique can be utilized to the real electromagnetic radiation hazard test.

• Bulletin of the Korean Space Science Society
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• 1993.10a
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• pp.11-11
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• 1993

The Korean sounding rockets(KSR) 1, 2 equigped with the UV optical detectors have been launched at An-heung, Chungchongnam-do, of June 4 and September 1, 1993,respectively. The UV detector is used to measure the attenuation of solar UV radiation for various frequency bards in the stratospgere. We obtained the profile of the ozone number density within the altitulde of 15 - 30 km by applying the Beer-Lambert law. It is found that the maHimum of the ozone distribution occurs near 2sht which is quite consistent with the mean value in the mid-latituderegions. We will also compare our results froiu KSR 1,2 with the other observational data from the Dobson speceo meter at Yonsei Univ. and the LIDAa which were performed simultaneously with the sounding rocket experiments.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.540-543
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• 2003

This paper presents design and manufacture of RF type non-contact radiological dosage measuring device. It also concerns on the broad out-line and the ways of improvement about RF type non-contact radiation measuring device. Measuring radiological dosage with non-contact RF, the stability and efficiency of the measure have been improved by reforming constant current circuit. Furthermore, applying communication protocol in process makes it possible to achieve faster and more accurate communication than old circuit. On the base of those, RF type non-contact radiological dosage measuring device which consists of radiological dosage measuring module and Reader module has been designed and manufactured. While testing communication against embodied device, the possibility of the field application could be confirmed.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.165-173
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• 1994

Retroreflector is different from other reflecting surfaces as it mades reflection in which radiation is returned in directions close to its incoming direction. Because of this characteristics, retroreflectors find many applications in traffic safety related areas. Retroreflectors are usually made using comer cubes, or partially coated glass beads. These glass beads can be made very small, so that they can be coated on sheets or mixed with paints. The design of glass type retroreflector depends on glass bead's shape and material, and its optical characteristics are related to the refractive index of glass. In this paper, a method of anlyzing glass bead type retroreflector's sptical characteristics with respect to shape and optica property of the glass, is presented. First, the coefficient of retroreflection, which is a measure of retroreflector's optical characteristics, is derived analytically using geometrical optics method. And the result is plotted using numerical methods. The results show good match with those obtained experimentally, which were supplied from a commercial retroreflector manufacturer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.2
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• pp.131-138
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• 2009

The radioprotect effects of fractinated fucoidan, derived from Undaria pinnatifida sporophylls, were examined in lung injured rats treated with partial body irradiation. The right lung of Sprague-Dawley rats, eight separately grouped by including radiation only control group (ROG) and fucoidan+radiation treated group (FRG), were treated with various fraction of Undaria-derived fucoidan every other day by intraperitoneal injection 6 days prior to irradiation and during monitoring at 24 hours, 48 hours, 2 weeks, 4 weeks and 12-weeks post-irradiation of 6 Mev/2 Gy. The rats were euthanized at completion of the treatment. Tissue samples from the injured lung, fixed in formaldehyde using lung perfusion prior to extraction, were H/E stained for histological analysis using optical microscopy. Interstitial congestion (IC), hemorrhage in alveolar sac (HM), number of macrophage (MP) and alveolar wall thickness (AWT) as a measure of early indication of fibrosis were measured. AWTs in 24 hrs post-irradiation rats increased in comparison with $2.49{\pm}0.06{\mu}m$ of control group by $3.67{\pm}0.09{\mu}m$, $3.21{\pm}0.08{\mu}m$ (p=0.013), $2.98{\pm}0.08{\mu}m$ (p=0.00) in ROG, F1-fucoidan+radiation, and F3-fucoidan+radiation group, respectively. AWT of the ROG was further increased by $4.30{\pm}0.13{\mu}m$ in the 12 weeks post-irradiation group, but AWT on average was $2.56{\pm}0.05{\mu}m$ in the FRG. MP in the 24 hrs post-irradiation group markedly increased in comparison with $2.6{\pm}0.34/0.14\;mm^2$ of the control group by $8.0{\pm}1.48/0.14\;mm^2$ in the ROG, but it was only $3.6{\pm}0.48/0.14\;mm^2$ in F3-FRG. MP in the 12 weeks post-irradiation group was $7.2{\pm}1.28/0.14\;mm^2$ in ROG, but it was $2.8{\pm}0.37/0.14\;mm^2$ or $2.4{\pm}0.4/0.14\;mm^2$ (p<0.05) in the FRG. In addition, increased IC and HM in ROG were relatively smaller in FRG of the 24 hr and 12 weeks post-irradiation rats. In conclusion, Undaria pinnatifida sporophylls-derived fucoidan fractions exhibited radioprotectant activity on injured rat lung subjected to X-ray irradiation. However, success was variable according to the fractions and also time of injection post injury.