• Transactions on Electrical and Electronic Materials
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• 제1권3호
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• pp.29-33
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• 2000

The crystallographic and high frequency characteristics of $Fe_{73.9}Cu_{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$ soft magnetic alloys were investigated under magnetic field annealing, The crystallization fraction of annealed samples with longitudinal magnetic fields is higher than that of samples without magnetic field. When the transverse magnetic field is applied, the crystallization fraction does not increases but decreases until $500^{circ}C$. It is found that for samples, the saturation induction are all same with 1.3 T. The coercive field of as-cast samples is 1.03 A/cm, but in annealed samples it decrease from 0.56 to 0.1A/cm with increasing annealing temperature from 400 to $550^{circ}C$. The squareness of annealed samples under transverse magnetic field has a small value than that of both without field and with longitudinal field annealing. It is noted that the magnetic field annealing with transverse direction to amorphous $Fe_{73.9}Cu_{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$ profoundly influenced on the Mossbauer spectra in contrast to that with longitudinal direction and without magnetic field.

• 한국초전도ㆍ저온공학회논문지
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• 제19권1호
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• pp.30-35
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• 2017

The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces (F) and trapped magnetic field (B) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance (F-d) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density ($J_c$) of the (001) surface. For the (001) samples with t=5-18 mm, the maximum magnetic levitation forces ($F_{max}s$) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness (t=5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic fields.

• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.52-56
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• 2022

Single-grain (c-normal or c-parallel) and multi-grain YBCO superconductors were prepared by a melt growth process with/without seeding. The magnetic levitation force and trapped magnetic field at liquid N₂ temperature (77 K) of the YBCO superconductors were investigated. Samples for the levitation force measurement were zero-field cooled (ZFC) to 77 K, and samples for trapped field measurement were field-cooled (FC) using Nd magnets. As for the magnetic levitation force, the c-normal, single grain sample showed the largest value, whereas the multi-grain sample showed the lowest value. The trapped magnetic field of the c-normal and c-parallel single-grain samples was 4-5 times that of the multi-grain sample. In addition, as the external magnetic field (the number of magnets) increased, the both properties increased proportionally. These results were explained in terms of the orientation dependence of the levitation forces and the magnetic field trapping capability of the YBCO superconductor.

• 한국재료학회지
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• 제3권5호
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• pp.482-496
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• 1993

Radiation damage and contamination of silicons etched in the $CF_4+H_2$ and $CHF_3$ magnetron discharges have been characterized using Schottky diode characteristics, TEM, AES, and SIMS as a function of applied magnetic field strength. It turned out that, as the magnetic field strength increased, the radiation damage measured by cross sectional TEM and by leakage current of Schottky diodes decreased colse to that of wet dtched samples especially for $CF_4$ plasma etched samples, For $CF_4+H_2$and $CHF_3$ etched samples, hydrogen from the plasmas introduced extended defects to the silicon and this caused increased leakage current to the samples etched at low magnetic field strength conditions by hydrogen passivation. The thickness of polymer with the increasing magnetic field strength and showed the minimum polymer residue thickness near the 100Gauss where the silicon etch rate was maximum. Also, other contaminants such as target material were found to be minimum on the etched silicon surface near the highest etch rate condition.

• 한국동물학회지
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• 제35권3호
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• pp.332-338
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• 1992

Samples of ho subspecies of striped field mice, Apodemus agrarius coreue & Apodemus ograrius cheiuensis, from four localities in Korea were used for the analyses of mitochondrial DNA fragment patterns resulted from the digestion with eight restriction enzvmes. A total of 31 fragments were recognized and 15 clones were revealed. The 15 clones were grouped into four major subgroups. One sample from Cheongiu was distinct, and formed one of the four major subgroups: the mean divergence wi6 other subgroups was 4.6 per cent, and extensive analyses using samples from various sites are necessary to clarify the taxonomic status of the subgroup. Samples from Cheju island constituted another subgroup, and they should be named as hpodemus cheiuensis. Samples from Wan island composed still another subgroup, and thew seemed to be another population of Apodemus chejuensis: further analvses are needed for the classification of Apodemus cheiuensis. In the last subgroup composed of six of seven samples from Cheongiu and four samples from Haenam, two samples from Cheonsiu and one sample from Haenam were identical in their mitochondrial genotypes, indicating that these striped field mice from Cheongiu and Haenam have close maternal relationship.

• 한국환경보건학회지
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• 제34권6호
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• pp.403-413
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• 2008

Toxic effect of methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA) and formaldehyde (FA) on microbial activity and diversity was compared in rice field, leek patch, and tidal mud flat soil samples. MTBE, TBA and FA with different concentrations were added into microcosms containing these soil samples, and placed at room temperature for 30 days. Then the microbial activities such as dehydrogenase and viable cell numbers and microbial community using a DGGE (Denaturing gradient gel electrophoresis) fingerprinting method were measured. Among the samples, dehydrogenase activity in rice field was inhibited the most by MTBE, TBA and FA. The toxic effect was higher according to the following orders: FA > MTBE > TBA. Dominant species in the microcosms contaminated with MTBE, TBA and FA were Chloroflex, Bacilli, gamma-proteobacteria in the rice field sample, Sphingobacteria, Flavobacteria, Actinobacteria, Bacilli, gamma-proteobacteria in the leek patch sample, and Sphingobacteria, Flavobacteria, delta-proteobacteria, gamma-proteobacteria in the tidal mud flat sample.

• 한국자기학회지
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• 제8권1호
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• pp.13-20
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• 1998

초미세결정립과 비정질을 동시에 포함하는 리본형 Fe73.9Cu1.0Nb3.5Si14.0B7.6 합금을 자기장 중 열처리한 시편의 결정？적 특성 및 고주파 연기자 특성을 인가 자기장과 열처리 온도에 따라하여 조사아였다. 제조된 리본의 표면에 석출된 Fe-Si 초미세결정립은 (400) 우선방위를 나타내는 동시에 리본길이방향으로 [011] 결정측이 형성되어 있음을 확인하엿다. 자기장을 인가하지 않거나 길이방향으로 자기장을 인가하여 열처리할 때 45$0^{\circ}C$에소 Fe-Si 초미세결정립이 석출되다, 폭방향의 자기장을 인가한 경우 초미세결정립의 석출은 지연되어 55$0^{\circ}C$에서 나타남을 확인하였다. 길이방향으로 자기장을 인가할 때 시편의 결정화 정도는 외부 자기장을 인가하지 않은 경우에 비해 조금 증가하였다. 그러나, 시편의 각도를 기울여 측정된 X-선 회절패턴으로부터 시편내부는 표면과 달리 결정화가 진행되고 있음을 확인하였다. 열처리한 시편의 포화자기유도는 1.3T로 비슷하였다. 열처리전 리본의 보자력의 크기는 1.06A/츠이었으나, 열처리한 시편은 열처리 온도가 40$0^{\circ}C$에서 55$0^{\circ}C$로 증가함에 따라 0.56A/cm에서 0.1A/cm로 감소하였다. 폭방향의 자기장을 인가한 경우 각형비는 자기장을 인가하지 않거나 길이방향으로 자기장을 인가하여 열처리한 시편의 각형비보다 작았다.

• 자원환경지질
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• 제53권6호
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• pp.743-753
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• 2020

본 연구는 폐석탄광산인 옥동탄광 하류에 위치한 밭토양과 논토양을 대상으로 중금속함량, 광물조성, 분광특성을 고찰하였다. X선 형광분석 결과 밭토양과 논토양 모두 비소가 토양환경오염 우려기준을 초과하여 검출되었으며 밭토양이 논토양보다 중금속오염지수가 상대적으로 높은 것을 확인하였다. X선 회절분석 결과 밭토양과 논토양 모두에서 석영, 방해석, 고령토, 일라이트, 스멕타이트, 자철석 그리고 적철석 광물이 검출되었다. 또한 유기물 분석을 실시한 결과 밭토양의 유기물 함량 변이가 더 큰 것으로 나타났다. 분광분석 결과 밭토양과 논토양의 전체적인 반사도 곡선의 양상과 흡광특성은 유사하게 발현됨을 확인하였다. 490nm 부근과 900nm 부근에서 토양 내 산화철에 의해, 1410nm, 1910nm 부근과 2200nm 부근에서 점토광물인 고령토와 스멕타이트군에 의한 흡광특성이 두드러지게 나타났으며 유기물의 함량이 많을수록 반사도가 감소하였다. 흡광 깊이는 밭토양과 논토양 모두 흡광특성이 발현되는 곳에서 오염 지수가 높아짐에 따라 흡광깊이는 얕아졌으며, 유기물 함량이 증가함에 따라 490nm 부근과 1916nm 부근의 흡광깊이가 얕아지는 경향을 보였다.

• 한국축산식품학회지
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• 제43권3호
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• pp.412-427
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• 2023

The effects of wet-aging using a commercial refrigerator (CR, 4℃) and a pulsed electric field refrigerator (PEFR, 0℃ and -1℃) on the quality of sous vide pork loin were analyzed. The moisture and fat contents, pH, CIE L^*, CIE b^*, chroma, and shear force of the wet-aged samples were lower than those of the raw meat samples, whereas the water holding capacity (WHC) was higher. The PEFR group showed higher pH, CIE b^*, chroma, and WHC and lower weight loss than the CR samples. Electronic nose analysis indicated that positive flavor compounds were induced whereas negative flavor compounds were inhibited in the PEFR group. Wet-aging increased the sourness, saltiness, and umami of sous vide pork loin; the PEFR 0℃ samples showed the highest umami. Sensory evaluation indicated that wet-aging improved the color of sous vide pork loin. The PEFR 0℃ samples were rated higher than the raw meat and CR samples for all sensory traits. In conclusion, sous vide after wet-aging using a PEFR improved the quality of pork loin.

• 대한공간정보학회지
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• 제24권1호
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• pp.121-128
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• 2016

많은 연구들에서 영상자료와 분류 알고리즘 측면에서 분류정확도를 비교하였지만, 참조자료 또는 분석자에 의존하는 훈련샘플에 의한 분류정확도 비교와 관련된 연구는 부족한 실정이다. 본 연구는 감독분류에 있어 훈련샘플로써 지상 분광반사자료의 유용성을 평가하고자 하였다. 이를 위하여 초분광영상과 다중분광영상을 대상으로 영상 수집 훈련샘플과 지상 분광반사자료를 사용하여 분류 정확도를 비교하였다. 그 결과 영상 수집 훈련샘플 사용 시 초분 광영상과 다중분광영상에서 공통적으로 약 90%의 분류정확도를 얻을 수 있었다. 그러나 지상 분광반사자료를 훈련 샘플로 사용하면 초분광영상의 경우 약 10%p, 다중분광영상의 경우 약 20%p의 분류정확도 감소가 발생하였다. 특히 다중분광영상에서 분광반사특성이 유사하게 나타나는 클래스들의 경우 분류정확도가 초분광영상에 비해 매우 낮게 나타났다. 따라서 지상 분광반사자료는 다중분광영상에 적용하는 데에는 한계가 있지만, 초분광영상을 이용한 토지피복분류에 있어 유용한 훈련샘플이 될 수 있다.