• Journal of Veterinary Clinics
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• v.41 no.3
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• pp.157-164
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• 2024

The standard radiation protection method in the angiography suite involves the use of a thyroid shield, a lead apron, and lead glasses. However, exposure to substantial amounts of ionizing radiation can cause cataracts, tumors, and skin erythema. A newly developed curtain-type radiation protection device consists of a curtain drape composed of a five-layer bismuth and lead acrylic head-shielding plate, with both bearing an equivalent 0.25 mm lead thickness. In this study, a quality assurance phantom was used as the patient to create radiation scatter from the radiographic source, and an anthropomorphic mannequin phantom was used as the interventionalist to measure the radiation dose at seven different anatomical locations. Thermoluminescent dosimeters were used to measure the radiation dose. The experimental groups consisted of all-sided or one-sided curtain set-ups, the presence or absence of a conventional shielding system, and the orientation of beam irradiation. Consequently, the curtain-type radiation protection device exhibited better radiation protection range and capabilities than conventional radiation protection systems, especially in safeguarding the forehead, eyes, arms, and feet, with minimal radiation exposure. Moreover, the mean shielding ratios of the conventional shielding system and curtain-type radiation protection device were measured at 51.94% and 93.86%, respectively. Additionally, no significant decrease in the radiation protection range or capability was observed, even with changes in the beam orientation or one-sided protection. Compared with a conventional shielding system, the curtain-type radiation protection device decreased radiation exposure doses and improved comfort. Therefore, it is a potential new radiation protection device for veterinary interventional procedures.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1561-1563
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• 2004

In this paper, we researched the dielectric properties and voltage dependence on slice XLPE sheet from 22[kV] and 154[kV] power cable. We studied effects for impurities and water for semiconductor shield through a dielectric properties experiment to estimate performance of insulating materials in power cable. Capacitance and tan${\delta}$ of 22[kV], 154[kV] were 53/43[pF] and $7.4{\times}10^{-4},\;2.1510^{-4}$. In these results, the trend was increased with the increase of temperature. The tan${\delta}$ of XLPF/ semiconductor layer was increased as compared with that of XLPE. Dielectric properties reliability of tan${\delta}$ was small.

• Tunnel and Underground Space
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• v.11 no.4
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• pp.339-343
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• 2001

Shield tunnel having circular section located in the soil or soft rock layer is liable to deform in such a way that its two diagonal diameters crossing each other expand and contract alternately during earthquakes. Based on this knowledge, the ground-tunnel interaction effect for this particular vibration mode is investigated. The ground surrounding a tunnel is assumed to be a homogeneous elastic medium. The bonded boundary condition on the ground-tunnel interface is considered. This suggests a firm bond between the ground and the tunnel lining. As Poisson's ratio and stiffness of the ground increases, the strain induced within the tunnel lining increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.130-134
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• 1997

The structural defects, impurities, degree of crosslinking and shrinkage of 38 field-aged distribution cables have been analyzed. For the comparison of data, 9 new cables were also subjected to an analysis. It is observed that the structural defects and degree of crosslinking show a radial profile. The structural defects are different depending on the manufacturer. A large amount of impurities is present in the insulation shield, which hold true for the new cables manufactured recently. The degree of crosslinking near both shields is lower than that at the central region of the insulation layer. It was also found that, in some cal)toes, the ins난lation was not fully crosslinked. The shrinkage of field-aged cables is higher than that of new cables.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.609-614
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• 2002

In this study, we investigated the effects of hot water on the aging of URD power cables due to the hot water ingress to power distribution lines. Hot water contacted and non-contacted cables extracted from 2 distribution lines were characterized by the measurement of oxidation induction time(OIT) and chemical structure. In OIT measurement, hot water contacted cables showed the shorter OIT than non-contacted ones. Especially, hot water contacted insulation layer near insulation shield showed the shortest OIT. In chemical structure analysis, the antioxidant content was decreased and the acid concentration was increased by hot water ingress. From this results, it can be concluded that the hot water ingress to power cable may be accelerate the aging by means of antioxidant consumption.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.59-65
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• 2000

The purpose of this study is to investigate the details of unsteady heat transfer in a heated fire door. This investigation is carried out numerically for two dimensional fire door which is composed of normal plasterboard and mild steel including air layer or heat shield. It is shown from the results that the recirculation occurs at the inner part of fire wall due to gravity force by temperature difference. The case I gives better adiabatic effect than the case II because temperature around the fire wall reachs at $230.96^{\circ}C$ in the case I and reachs at $450.37^{\circ}C$ in the case II.

• 전기의세계
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• v.22 no.3
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• pp.13-24
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• 1973

In this report, as a method to solve the problems on impulse insulation coordination in ribbon core transformer owing to it's BIL stepping up, new design to alter winding distribution of multiple-layer concentric winding to Convex type winding is proposed. The main focus of this method is to settle the weakness of axial direction insulation strength and as a result of theoretical analysis through experiment of model transformers, the following conclusions are obtained; (a) As the electric loadings in a design which increases by strengthenning axial direction insulation endurance in presently avarilable transformers owing to it's BIL stepping up can be restricted in Convex type winding, reasonable design will be suited to the transformer with higher BIL. (b) Convex type winding is a very improved insulation design in respect of insulation coordination because it has shield plate effect to even impulse oscillation. (c) There is a disadvantage to cause leakage flux to increase in Convex type winding, however, the constancy of electric loadings in a design in spite of BIL stepping up restricts the increase of leakage flux to some extent.

• Journal of Magnetics
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• v.7 no.2
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• pp.55-58
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• 2002

MR transfer behaviors of the permanent magnet biased spin valve MR sensors with SyAF (synthetic antiferromagnet) layers were studied by micromagnetics modeling. For narrow track MR heads, various height to width ratios were considered together with strength of permanent magnets which stabilities the free layed As the MR sensor width is reduced to $0.12 \mu{m}$, sensor height less than 0.09 ${\mu}{\textrm}{m}$ is needed to show good linearity and the Mr.t of permanent magnets smaller than 0.2 memu/$cm^2$ is sufficient for the domain stabilization. The conditions for single domain behavior of the free layer were also investigated through optimizing the biasing strength of permanent magneto the shield gap and the aspect ratio of MR sensor.

• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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• pp.46-49
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• 2012

The selection of the temperature sensor in the cryogenic system depends on the temperature range, shape and accuracy. The accuracy of the temperature sensor is essential to improve the reliability of experiment. We have developed the variable temperature cryostat using a two-stage cryocooler. In order to reduce heat load, thermal shield is installed at the first stage with MLI (Multiple layer insulation). We have also developed the sensor holder calibrating more than twenty sensors at the same time for saving time and money. The system can calibrate sensor at variable temperature by controlling electric heater. In this paper, we present design and fabrication of variable temperature cryostat and representative result of Cernox sensor calibration.

• Applied Microscopy
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• v.52
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• pp.4.1-4.11
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• 2022

Field emission scanning electron microscopy (FESEM) is an essential tool for observing surface details of specimens in a high vacuum. A series of specimen procedures precludes the observations of living organisms, resulting in artifacts. To overcome these problems, Takahiko Hariyama and his colleagues proposed the concept of the "nanosuit" later referred to as "NanoSuit", describing a thin polymer layer placed on organisms to protect them in a high vacuum in 2013. The NanoSuit is formed rapidly by (i) electron beam irradiation, (ii) plasma irradiation, (iii) Tween 20 solution immersion, and (iv) surface shield enhancer (SSE) solution immersion. Without chemical fixation and metal coating, the NanoSuit-formed specimens allowed structural preservation and accurate element detection of insulating, wet specimens at high spatial resolution. NanoSuit-formed larvae were able to resume normal growth following FESEM observation. The method has been employed to observe unfixed and uncoated bacteria, multicellular organisms, and paraffin sections. These results suggest that the NanoSuit can be applied to prolong life in vacuo and overcome the limit of dead imaging of electron microscopy.