• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.18-22
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• 2012

This paper presents the magnetic field analysis of the racetrack double pancake field coil for the 10 MW class superconducting wind turbine which is considered to be the next generation of wind turbines using the 3 Dimensional FEM(Finite Elements Method). Generally, the racetrack-shaped field coil which is wound by the second generation(2G) superconducting wire in the longer axial direction is used, because the racetrack-shaped field coil generates the higher magnetic field density at the minimum size and reduces the synchronous reactance. To analysis the performance of the wind turbines, It is important to calculate the distribution of magnetic flux density at the straight parts and both end sections of the racetrack-shaped high temperature superconductivity(HTS) field coil. In addition, Lorentz force acting on the superconducting wire is calculated by the analysis of the magnetic field and it is important that through this way Lorentz force can be used as a parameter in the mechanical analysis which analyzes the mechanical stress on the racetrack-shaped field coil.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.15-18
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• 2003

Fault current limiters (FCL) are extensively needed to suppress fault currents, especially for trunk power systems heavily connected to high voltage/large current transmission lines. Due to its ideal electrical behavior, high-temperature superconductor fault current limiter (HTSFCL) becomes one of the most important developing trends of limiters in power system. This paper describes the result of an investigation of the dielectric characteristics of turn-to-turn insulation for pancake and solenoid type reactor coil in liquid nitrogen. The influence of thickness in a variety length, on AC, DC and impulse surface flashover has been investigated. Also, the relationships between the number of turn and breakdown characteristics were clarified. The information gathered in this test series should be helpful in the design of liquid nitrogen filled DC reactor type HTSFCL.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.869-870
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• 2006

일반적으로 초전도선재를 이용한 코일의 전자기력에 의한 스트레스 계산에 있어서는 코일의 전류밀도분포와 자속밀도분포의 선형적인 관계를 이용하나 아직까지 초전도체 특유의 비선형적인 특성을 이용한 스트레스의 계산은 미비하다. 본 논문에서는 13턴의 소형 싱글팬케이크 코일을 초전도의 특성을 적용해 해석하고 인가전류가 $0.3I_c,\;0.5I_c,\;0.8I_c$ 인 경우에 대해서 전자기력에 의한 코일의 스트레스를 유한요소법으로 계산하였다. 계산 결과 코일의 radial stress와 hoop stress는 모두 코일의 자속밀도분포와 유사한 모습을 나타내었다.

• Journal of the Korean Dietetic Association
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• v.8 no.3
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• pp.289-300
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• 2002

The purpose of this study was to investigate the intake and preference of Kimchi in middle school students. A questionnaire was used as the instrument of investigation. The subjects were 375 male and 278 female students in Masan and Changwon City. The main results of this study are as follows. Fifty-nine point seven percent of the subjects liked Kimchi, whereas 3.7% of them disliked it, and the main reason liking Kimchi was 'hot taste' of Kimchi. Korean cabbage Kimchi and cubed radish Kimchi were highly preferred. And the preferred dishes made with Kimchi were stir-fried rice with Kimchi, Kimchi stew, pan-fried Kimch, seaweed rice with Kimch, Kimch pancake, Mandu with Kimchi, pork stew with Kimch. More than 90% of the subjects had eaten 6 kinds of Kimchi : Korean cabbage Kimchi, cubed radish Kimchi, radish leaves Kimchi, radish root & leaves Kimchi, watery radish Kimchi, white Kimchi. The frequency of Kimchi intake was 55.1% of the subjects ate Kimchi in every meal time, and 21.9% ate 2 times in a day. They preferred 'well fermented' and 'freshly prepared' Kimchi, and it was significantly difference between gender, male students more liked 'freshly prepared', whereas female students more liked 'well fermented' Kimchi(p<0.01).

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.111-111
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• 2016

Two step PEO ceramic coatings were formed on AZ91 magnesium alloy in $ZrO_2$ nanoparticles and $K_2ZrF_6$ based colloidal electrolyte solution for various voltages. Surface and layers tructure of the coatings was analyzed using SEM (ScanningElectronMicroscope). Structure analysis revealed that surface of the coating was transferred from individual pancake or craters-based structure to cluster-based structure with increasing the voltage of the secondary step process. Further, it was confirmed that the cluster zone was richin Zr-based complexes and formed due to high intensives parks. Increase in the Zr contents as discovered from the EDS analysis confirmed the rise in amorphous form of the Zr-based species, which justified the results of XRD where no increase in the intensity of Zr-based species was observed with increase in voltage. Potentiodynamic polarizariotion and impedance spectroscopy techniques were used to evaluate the corrosion performance of the coatings. The highest corrosion resistance was found for coatings prepared at 240V. The same specimen was found having highest and uniform vickers hardness ~1070.5 HV. The superior mechanical and electrochemical properties of the said coating can be attributed to the defect-less microstructure and the optimal role of $ZrO_2$ nanoparticles in the secondary PEO process at 240V.

• Culinary science and hospitality research
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• v.13 no.4
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• pp.19-30
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• 2007

The purpose of this study was to gather useful information for establishing an efficient marketing direction by investigating the flavor, serving patterns, price and cooking method of Dong-rae Pajeon which is a native local food of Pusan area. A questionnaire was answered by 226 citizens who experienced Dong-Lae Phajeon. The study data were analyzed by frequency analysis, t-test, ANOVA, and multiple regression analysis. The findings are summarized as follows: The flavor, presentation, types of oil, and price of Dong-rae Pajeon had influence on the satisfaction of respondents. To globalize Dong-rae Pajeon, 'developing its cooking method', 'decreasing its price', and 'developing its serving patterns' should be considered.

• Proceedings of the KIEE Conference
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• summer
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• pp.773-775
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• 2004

최근 높은 임계전류를 지닌 고온초전도선재를 이용한 초전도 전력기기의 개발이 활발히 이루어지고 있다. 고온초전도선재의 임계전류는 자장에 대한 의존성을 지니고 있으며 이로 인해 고온초전도선재가 코일의 형태로써 초전도 전력기기의 개발에 이용되는 경우, 권선 방식에 따라 다른 전기적 특성을 지니게 된다. 이러한 특성은 초전도선재의 전력기기의 효율에 큰 영향을 미치므로 권선 방식에 따른 코일의 특성을 연구하는 것은 초전도선재를 이용한 전력기기의 효율을 높이는데 있어서 중요한 의미를 갖는다. 본 논문에서는 권선 방식에 따른 코일의 특성을 비교하기 위해 동일한 턴 수와 사용 선재길이를 가진 팬케이크 코일과 솔레노이드 코일을 설계, 제작하고 두 코일의 임계전류를 측정하였다. 또한 인가전류에 대한 두 코일의 전압, 저항특성과 교류손실 특성을 측정하고 비교하였다. 측정결과, 두 코일의 임계전류는 솔레노이드 코일이 109A로 팬케이크 코일에 비해 약 $36\%$ 더 높았다. 코일에 가해준 인가전류가 증가함에 따라 코일에서 발생하는 전압 중 손실에 관련된 저항성 성분의 전압이 변화하고 있음을 확인하였다. 또한 교류손실은 인가 전류의 피크값이 팬케이크 코일의 임계전류 이하인 구간에서 팬케이크 코일이 솔레노이드 코일의 교류손실보다 9배 크며, 팬케이크와 솔레노이드의 임계전류 사이에서는 8.3배 컸다.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.735-737
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• 2003

A superconducting motor consisting of high temperature superconducting (HTS) rotor and air-core stator is under development in Korea Electrotechnology Research Institute. HTS motor was designed for having the rated power of 100hp at 1800 rpm. HTS field winding is composed of sixteen HTS race track shaped coils wound with stainless steel-reinforced Bi-2223 tape conductor by react and wind fabrication method. Nomex Paper was used for electrical insulation. Each of four magnet pole assemblies was constructed with four double pancake sub-coils, mechanically stacked and electrically in series. Four magnet assemblies were fixed on an aluminum support structure to make effective heat transfer. Critical current (Ic) of HTS field winding was 41A but minimum Ic of sub-coils was 35A at 77K and self field. Joule heat generated in HTS field winding was 2.11W at 77K and 35A.

• Proceedings of the KIEE Conference
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• summer
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• pp.851-853
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• 2004

This paper deals with current distribution analysis of the windings of a superconducting transformer with BSCCO-2223 High Tc Superconducting (HTS) tapes. Current distribution of HTS windings wound in parallel is analyzed by electromagnetic field analysis of finite element method and verified by experiments. For the sake of uniform current distribution, windings must be transposed so to make the impedances of each strands same. The parallel HTS tapes were transposed between the pancakes via non-superconducting joints because it is hard to make transpositions inside the pancake windings. In order to measure current distribution, test windings are fabricated and experimented for both transposed and non-transposed windings. We compared test results with calculated ones.

• Korean journal of food and cookery science
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• v.19 no.5
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• pp.659-666
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• 2003

The purpose of this study was to standardize the various methods and recipes of Hwajeun (glutinous rice pancake with flower) that appeare in the literature. For this purpose, the effects on sensory and physical characteristics of Hwajeun in various kinds of dipping syrups (S1 : honey, S2 : rice syrup, S3 : com syrup, S4 : sugar syrup and S5 : sugar) during storage for 24hrs were investigated. This experiment consisted of the measurement of water content, color difference meter, texture analyser and sensory evaluation for acceptance (color, flavor, moistness, softness, chewiness, adhesiveness, sweetness and overall acceptability). The moisture contents decreased with increasing storage time, indicating that S1 had a significantly (p<0.01) high value until 12hrs. The colorimetric values of lightness (L), redness (a) and yellowness (b) decreased and the total color difference values ($\Delta$E) increased with increasing storage time. In the two bite compression test, the hardness of S1 and S3 showed significantly (p<0.0001) lower values than other samples. As a result of the sensory evaluation for Hwajeun prepared with various kinds of dipping syrup, S1 and S3 were most preferred in color, flavor, moistness, chewiness, adhesiveness, sweetness and overall acceptability of sensory evaluation.