• Journal of Astronomy and Space Sciences
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• 제35권4호
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• pp.219-225
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• 2018

Cosmic rays are ions that move at relativistic speeds. They generate secondary cosmic rays by successive collisions with atmospheric particles, and then, the secondary particles reach the ground. The secondary particles are mainly neutrons and muons, and the neutrons are observed by the ground neutron monitor. This study compared the diurnal variation in cosmic ray intensity obtained via harmonic analysis and that obtained through the pile-up method, which was examined in a previous study. In addition, we analyzed the maximum phase of the diurnal variation using four neutron monitors with a cutoff rigidity below approximately 6 GV, located at similar longitudes to the Oulu and Rome neutron monitors. Expanding the data of solar cycles 20-24, we examined the time of the maximum cosmic ray intensity, that is, the maximum phase regarding the solar cyclic modulation. During solar cycles 20-24, the maximum phase derived by harmonic analysis showed no significant difference with that derived by the pile-up method. Thus, the pile-up method, a relatively straightforward process to analyze diurnal variation, could replace the complex harmonic analysis. In addition, the maximum phase at six neutron monitors shows the 22-year cyclic variation very clearly. The maximum phase tends to appear earlier and increase the width of the variation in solar cycles as the cutoff rigidity increases.

• 한국조경학회지
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• 제34권4호
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• pp.18-36
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• 2006

The purpose of this research was to establish a green-networks from the perfective of landscape ecology in order to improve the function of urban green spaces. The study site was Dalsu-Gu in Daegu City. This research consisted of three phases. In the first phase, field surveys were carried out in order to understand existing distribution pattern of green spaces in the study site. 533 green spaces surveyed in the first phase were classified into 7 patterns and 24 types. The total area of the green spaces in Dalsu-gu was 3,329ha. Specifically the area of the 'urban nature parks' type was 57.49% of the total area of green spaces in Dalsu-gu, and it was expected that 'urban nature parks' type can play important roles in the green-networks in Dalsu-gu. Two analysis with green spaces in 9 types including 'urban nature parks', 'rivers' and 'neighborhood parks' were performed to establish a basic network frame of the green-networks. In the second phase, 'mutual connectivity analysis' and 'mutual matrix analysis' were performed to select core green spaces of a green-networks using 'areas of each green space and a distance between each space' and 'a rate of green spaces and a rate of water permeable pavement'. The results of the second phase indicated that, in mutual connectivity analysis, large green spaces apart from each other were evaluated as having higher mutual connectivity than small green spaces near to each other. In mutual matrix analysis, the green spaces with higher mutual connectivity and the small green spaces near to each other were evaluated as having better mutual matrix. In the last phase, we structured a basic frame of the green-networks in Dalsu-Gu. The results suggested that the basic frame of the green-networks in Dalsu-Gu was composed on four green-network axes and its shape mirrored a cruciform(+) of northwest${\longleftrightarrow}$southeast directions and southwest${\longleftrightarrow}$northeast directions, The Duryu neighborhood park is at the central point of this green-networks.

• 조명전기설비학회논문지
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• 제16권5호
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• pp.14-21
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• 2002

본 논문은 4상과5상 하이브리드형 스텝모터의 모델링, 특성해석 및 디텐트 토크에 대한 고조파 저감을 대상으로 연구하였다. 이를 위하여 기계적인 모델링을 도출하였으며 자계해석을 위해서 퍼미언스법을 이용하였다. 이러한 해석 결과 본 모델에 대한 디텐트 토크를 얻을 수 있었다. 또한 두 모델 구조에 대한 상차의 특성해석 비교를 통하여, 본 모델에 대한 디텐트 토크를 유도해 낼 수 있었다. 이때 5상 스텝모터는 4상 스텝모터에 비하여 디텐트 토크의 감소와 스텝응답이 개선됨을 알 수 있었다. 해석결과 퍼미언스분포의 크기는 평균토크의 발생에 영향을 미치며, 고조파성분의 크기가 토크 리플의 크기를 발생함을 알 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.82.2-82.2
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• 2007

• 한국지반환경공학회 논문집
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• 제2권3호
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• pp.17-35
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• 2001

본 연구에서는 자연점토에 납, 구리, 아연, 카드뮴의 단일 흡착 시 온도변화에 따른 흙의 구성성분별 흡착거동을 살펴보기 위해 혼합 흡착-연속추출법(combined adsorption-sequential extraction analysis, CASA)을 사용하였다. 실험결과 납과 구리의 경우 약 50%이상의 분배가 탄산염 형태로 나타났고, 카드뮴의 경우 약 80%이상의 분배가 이온교환 형태로 나타났다. 아연의 경우 $25^{\circ}C$이하의 온도에서는 이온교환 형태로의 분배가 약 60%로 나타났고, $40^{\circ}C$이상의 온도에서는 탄산염 형태로의 분배가 50%이상으로 나타났다. 흙의 각 구성성분에 대한 흡착용량의 온도에 따른 영향은 철.망간 산화물과 유기물 형태에서 주로 발생하는 것으로 나타났다. 또한 이온교환 형태를 제외한 모든 형태에 대한 중금속들의 흡착 반응은 온도의 증가에 따라 흡착량이 증가하는 흡열반응(${\Delta}H^0$ >0)인 것으로 나타났다.

• 한국조경학회지
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• 제42권6호
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• pp.50-59
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• 2014

이 연구는 식생모듈박스에 적용한 레플렉숨을 중심으로 식물 생육특성 간의 관계 및 식물의 생육특성과 토양 물리적 특성의 관계를 파악하기 위하여 수행하였다. 이 실험에서 토양 물리적 특성과 식물 생육특성의 관계에 관한 연구의 분석은 SPSS Ver 19.0 for Window용 통계프로그램을 이용하여, 상관분석과 다중회귀분석을 실시하였다. 토양 물리적 특성과 생육특성의 다중회귀 분석 결과, 레플렉숨에 대한 회귀식은 초장=$3.993-14.070^*$(용적밀도)+$.233^*$(고상)+$.038^*$(액상)+$.068^*$(침투율)로 나타났으며, 이 중 용적밀도와 고상이 유의성 있게 나타났다. 레플렉숨에 대한 회귀식은 초폭=$2.931-33.925^*$(용적밀도)+$.566^*$(고상)+$.206^*$(액상)+$.027^*$(침투율)이며, 이 중 용적밀도와 고상이 유의성 있게 나타났다. 즉, 초장 및초폭과 토양의 물리적 특성은 일정한 회귀식으로 작성할 수 있다. 상하부 생체량과 건중량은 토양의 물리적 특성과 직접적인 상관성이 없는 것으로 나타났다.

• Journal of Ginseng Research
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• 제47권1호
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• pp.159-165
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• 2023

Background: Red ginseng marc, the residue of red ginseng left after water extraction, is rich in dietary fiber. Dietary fiber derived from fruits or vegetables can promote the proliferation of probiotics, and it is a key technology in the food industry to increase the productivity of probiotics by adding growth-enhancing substances such as dietary fiber. In this study, the effect of red ginseng dietary fiber (RGDF) on the growth of probiotic bacterial strains was investigated at the phenotypic and genetic levels. Methods: We performed transcriptome profiling of Lactiplantibacillus plantarum IDCC3501 in two phases of culture (logarithmic (L)-phase and stationary (S)-phase) in two culture conditions (with or without RGDF) using RNA-seq. Differentially expressed genes (DEGs) were identified and classified according to Gene Ontology terms. Results: The growth of L.plantarum IDCC3501 was enhanced in medium supplemented with RGDF up to 2%. As a result of DEG analysis, 29 genes were upregulated and 30 were downregulated in the RGDF-treated group in the L-phase. In the S-phase, 57 genes were upregulated and 126 were downregulated in the RGDF-treated group. Among the upregulated genes, 5 were upregulated only in the L-phase, 10 were upregulated only in the S-phase, and 3 were upregulated in both the L- and S-phases. Conclusions: Transcriptome analysis could be a valuable tool for elucidating the molecular mechanisms by which RGDF promotes the proliferation of L.plantarum IDCC3501. This growth-promoting effect of RGDF is important, since RGDF could be used as a prebiotic source without additional chemical or enzymatic processing.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권1호
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• pp.112-122
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• 2013

Current status of soil contamination with fluorine and its source were investigated. The basic principles and procedures of various techniques for the analysis of fluorine contents in soil and solid phase samples were summarized in this review. Analysis of fluorine in solid matrices can be achieved by two types of techniques: (i) UV/Vis spectrophotometer or ion selective electrode (ISE) analysis after performing appropriate extraction steps and (ii) direct solid analysis. As the former cases, the standard method of Korean ministry of environment, alkali fusion-ISE method, pyrohydrolysis, oxygen bomb combustion, aqua regia digestion-automatic analysis, and sequential extraction-ISE method were introduced. In addition, direct analysis methods (i.e., X-ray fluorescence spectrometry and proton induced gamma-ray emission spectrometry) and atomic spectrometry combining with the equipment for introducing solid phase sample were also reviewed. Fluorine analysis techniques can be reasonably selected through site-specific information such as matrix condition, contamination level, the amount of samples and the principles of various methods for the analysis of fluorine presented in this review.

• 한국분말재료학회지
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• 제30권5호
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• pp.402-408
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• 2023

This study focused on improving the phase stability and mechanical properties of yttria-stabilized zirconia (YSZ), commonly utilized in gas turbine engine thermal barrier coatings, by incorporating Gd₂O₃, Er₂O₃, and TiO₂. The addition of 3-valent rare earth elements to YSZ can reduce thermal conductivity and enhance phase stability while adding the 4-valent element TiO₂ can improve phase stability and mechanical properties. Sintered specimens were prepared with hot-press equipment. Phase analysis was conducted with X-ray diffraction (XRD), and mechanical properties were assessed with Vickers hardness equipment. The research results revealed that, except for Z10YGE10T, most compositions predominantly exhibited the t-phase. Increasing the content of 3-valent rare earth oxides resulted in a decrease in the monoclinic phase and an increase in the tetragonal phase. In addition, the t(400) angle decreased while the t(004) angle increased. The addition of 10 mol% of 3-valent rare-earth oxides discarded the t-phase and led to the complete development of the c-phase. Adding 10 mol% TiO₂ increased hardness than YSZ.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.211-213
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• 2009

Derivation of the phase error of hologram due to imperfection of a wave plate and analysis of the effect of phase error on 3-D image reconstruction of hologram are prexented.