• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.261-266
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• 2006

In this study, a scaled model chamber was built to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model by visualization equipment with laser apparatus. Four different kinds of measuring area were selected as experimental condition Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system and its software adopting two-frame grey-level cross correlation algorithm. The flow pattern reveals the large scale counter-clockwise forced-vortex rotation at center area.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.43.2-43.2
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• 2018

송전 및 배전선 선로에 사용되는 핵심 부품인 ACSR (Aluminum Conductor Steel Reinforced, 강심 알루미늄 연선) cable은 우수한 기계적 성질, 가벼운 중량, 내부식성 특징을 가지고 있어 송전 및 배전선 선로에 핵심 부품으로 사용된다. 하지만, 국내외 혹한 다설 지역에 설치된 ACSR cable에서 빙설해로 인한 단락 또는 지락 사고가 지속적으로 발생하고 있다. 빙설해에 의한 송전선로의 고장은 급격한 전압 강하로 인해 전기 품질에 큰 영향을 주어 민원제기의 주요 원인이 되며, 고장의 파급효과가 국지적으로 발생하지 않고 광범위하게 발생하는 특징이 있기 때문에 이에 대한 대응이 필요한 실정이다. 이러한 문제를 해결하기 위해 ACSR cable의 주 소재인 알루미늄에 대한 판상(Plate) 결빙강도 파악 및 결빙방지 소재개발 연구가 국내외에서 활발히 진행 중이나, 실제 원형의 전선다발이 나선형으로 감겨있는 구조의 ACSR cable 결빙 접합강도를 시험을 통해서 명확히 제시한 연구결과는 아직 보고된 바 없다. 본 연구에서는 실제 송전용 ACSR cable을 대상으로 얼음 간의 주 전단 응력, 파단에너지 등의 결빙특성을 정량적으로 측정할 수 있는 3D 스캔을 활용한 결빙특성 평가시험기를 개발하고, 345kV급 ACSR cable에 대한 결빙특성을 평가결과를 제시하였다. 또한 ACSR cable에 현재 상용화되고 있는 결빙방지 코팅소재를 적용함으로써 코팅소재의 적합성을 ARF(Adhesion reduction factor) 지표를 통해서 비교 평가한 결과를 포함한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.25-34
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• 2001

In this paper, discharge lamp ozonizer(DLO) of a new discharge type using superposition of gaseous electrical discharge for environment improvement was designed and manufactured. DLO is equipped with 3 electrodes(central ground electrode of discharge lamp type internal high voltage electrode of mesh type and external high voltage electrode of spiral type), and it is composed of double gap(gap between discharge lamp and internal electrode, gap between discharge lamp and external electrode). Internal and external electrodes are respectively applied AC high voltage which has 180[$^{\circ}$] phase difference. Ozone is generated by overlaying of each silent discharge which is respectively came from two gaps. At the moment discharge characteristics and ozone generation characteristics of DLO were investigated in accordance with quantity of supplied gas, discharge power and the number of DLO. When ozone generated by DLO was in contact with NO gas, removal characteristics was excellent, so it confirmed that DLO could be used as air environment improvement facility.

• Applied Microscopy
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• v.38 no.3
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• pp.265-273
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• 2008

We investigated the morphological differences of the ethnic hairs using scanning electron microscopy and transmission electron microscopy, sampled from African, Asian and Caucasian women. Transverse section of African hair had a highly elliptical type whereas those of Asian and Caucasian hairs had circular and elliptical types, respectively. The diameter of African hair showed wide variations from 90 to 115 ${\mu}m$. The diameter of Asian hair was 100 ${\mu}m$ and Caucasian hair had a lesser diameter of 80 ${\mu}m$ on average. African hair were much more damaged in cuticle layer compared with Asian or Caucasian hairs. In particular, endocuticle of cuticle cell had a lot of holes in it, which resulted that it tends to be easily broken. Phaeomelanin in the cortex of Caucasian hair had a concentrically helical structure in it.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.573-580
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• 2020

In this paper, the characteristics of the inductor and capacitor, which are the basic components of the circuit, are constructed in a form that can be used in the LTCC multilayer. The inductors and capacitors used for the analysis were designed with rectangular spiral structures and MIM structures inside dielectrics with a dielectric constant of 7, respectively. The measured results were extracted from each element of the equivalent circuit proposed by the curve fitting method and verified the validity of the proposed equivalent circuit based on the extracted results. The analyzed inductor and capacitor were implemented in the form of library and proved its usefulness by applying to Elliptical type 5th LPF design. The LPF was measured through practical production, and as a result, the insertion loss in the passband DC ~ 3.7 GHz was up to 1.0 dB, the return loss was 19.2 dB, and the attenuation in the rejection band was 23.9 dB, which was close to the design goal.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.25-29
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• 2010

To evaluate the usefulness of newly designed percutaneous bone biopsy needle for pumpkin's specimen collection. We manufactured three types of biopsy needle with different internal processing which were made of 10 mm-diameter acrylic material. We made the conventional type (Ct) similar to the clinical type then compared the test group. The type a (Ta) made 1 cm-length internal processing from the distal, type b (Tb) made taper, and type c (Tc) made internal processing like spiral configuration. We performed 20 times biopsy to get an 10 mm length specimen from pumpkin's surface and evaluated the success rate of the biopsy, length of the specimen, and determine internal processing type of the most suitable biopsy needle (ANOVA test). Success rates of Ct, Ta, Tb, and Tc were 55%, 80%, 90%, and 100%, respectively. The lengths of the specimen of Ct, Ta, Tb, and Tc were $5.6{\pm}1.1\;mm$, $5.9{\pm}0.87\;mm$, $3.9{\pm}0.77\;mm$, and $9.4{\pm}0.54\;mm$, respectively. All groups were statistically significant (p < 0.05) except the group between Ct and Ta (p = 0.28). Newly designed bone biopsy needle seems to be useful for obtaining enough specimen. Tc may be more effective than other types.

• Composites Research
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• v.15 no.4
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• pp.17-22
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• 2002

Small diameter composite helical springs (CS) are developed using a hot plated mold for reinforcement of common optical fiber jumper cord (OJC). The outer diameters of the springs are about 2 ~ 3mm. These springs are inserted into the OJC to protect the damage of an optical fiber from the sudden lateral load. Two types of CS, Yarn type (Y-type) and Band type (B-type), are manufactured to compare the effectiveness for the damage protection. The experimental works were conducted to check the effect of the CS covered around OJC on the mechanical and optical properties. Experimental observations show a considerable effect on the flexural resistance, hence slowing down the deterioration of the optical power by the internal damage of the fiber. Obtained main results are as follows: (1) Y-type CS has better protection abilities to lateral loading than B-types. (2) Compared with bare OJC, CS-OJC has less power loss under the loading. (3) OJC covered with the composite coil spring has a possibility for a practical usage with full fruits.

• Journal of Service Research and Studies
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• v.10 no.3
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• pp.1-22
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• 2020

This study was conducted to derive the new manager model in service economy era. It was logically explained that the modern economic society is different from the existing economic society, the modern organization that is the subject of management is different from the existing organization, and the tasks required by management are different from the existing tasks. It suggested the managerial model required for new managers. According to the proposed manager's model, the tasks required of new managers and essential qualities as managers to perform the tasks were presented. It suggested the role model that managers with required qualities should play. The role of a manager who becomes one with customers, the role of a manager who controls even his irrationality, the role of a manager who combines discernment and indiscriminateness, a flexible leadership role that combines charisma and tenderness, an administrator role that embraces regulations and non-regulations, and vision and non-vision. We derived the role of a manager who manages management, and a manager role model that utilizes both competition and non-competition. The managers engage in two opposing roles and perform management activities in a spiral dialectical cycle that develops while resolving the contradictions of each role. The method of embracing the two opposing parties internally and externally and the dialectical management execution process according to the change of the space-time axis were presented by borrowing the models of The Book of Change. Future research needs an empirical analytical study on this new Model. There is a need for studies that expand this study and develop it into a practical model and verify it in an analytical way.

• Analytical Science and Technology
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• v.15 no.6
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• pp.514-520
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• 2002

The electrothermal vaporization (ETV) hollow cathode glow discharge atomic emission spectrometer for analysis of liquid sample has been developed and characterized. This system has improved the sample introduction method of electrothermal vaporization and the hollow cathode glow discharge. The sample introduction method was possible to provide high analyte transport efficiency to the plasma by helix coil made of tungsten material. In addition, small volume samples (<$30{\mu}{\ell}$) could be used. The system has glow discharge cell with special design for improvement of precision. The effect of discharge parameters such as discharge power, gas flow rate has been studied to find optimum condition. The emitted light was effectively carried into detector by fiber optic cable in UV region. The calibration curve of Pb, Cd were obtained with 3 samples.