• 한국균학회지
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• 제8권1호
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• pp.59-62
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• 1980

Investigation on modification of aflatoxin structures by Pseudomonads was attempted as a biological detoxifiying process of mycotoxins. Firstly, when any variation of aflatoxin yield of Aspergillus parasiticus in a mixed culture with Pseudomonas aeruginosa was examined, there was no noticible effect by growth of Pseudomonads on aflatoxin yield of Asperillus sp. Secondly, when capacity of Pseudomonas aeruginosa utilizing aflatoxin as a carbon source for its growth was tested, there was some indication that aflatoxin might be used for growth of Pseudomonads. It was also noticed that the residual aflatoxin showed different migrating pattern compared with that of the intact aflatoxin by thin layer chromatography. Thirdly, the cell-free extract prepared from Pseudomonas aeruginosa grown in a glucose minimal medium supplemented with aflatoxin and the intact aflatoxins were incubated in the presence of $Mg^{++}$. After a certain length of incubation period, the reaction mixtures were applied on TLC plates. As a result, aflatoxins in the reaction mixture migrated differently as the control did. Such results may indicate that some changes of aflatoxin properties were induced by Pseudomonads.

• Journal of Biosystems Engineering
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• 제31권3호
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• pp.188-193
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• 2006

Elevation differences within a paddy field relate strongly to plant health, crop homogeneity, and pest control. For precision agriculture (PA), the elevation within a field should be precisely controlled. We analyzed variation in elevation within a rice paddy field over one crop cycle. The study took place in a rectangular plot (100 m x 30 m). Elevations within the a plots was measured by a laser-equipped surveying instrument, that could determine elevations to precisions of I mm. The test field was divided into grids with 30 squares; elevation was measured at the center of each 5 x 10-m grid square. This study measured elevation during nine observation periods from pre-plowing to post-harvest. Descriptive statistics showed the highest elevations after plowing due to soil disturbance. One-way analysis of variance (ANOVA) revealed significant elevation differences before and after plowing and transplanting, although elevations were similar over the period of crop growth. Comparison of pre-plowing and post-harvest data showed differences in elevations, indicating that elevation changes occurred during plowing, rice transplanting, plant growth, and harvesting. In summary, the above statistical analysis indicated that elevation changes occurred due to plowing but not during the plant growth season or due to harvesting.

• 한국식품저장유통학회지
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• 제7권1호
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• pp.124-131
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• 2000

Antibacterial activities of powdered spices(garlic , ginger, cinnamon and clove) against pathogenic Escherichia coli )157:H7 and Staphyloccus auresus were investigated. Spice powder was added in was exponetial phase of each bacterial culture . Growth inhibition was determined by the absorbance at 660nm and morphological changes of the cells were observed by transmission electron microscope (TEM). Ginger powder has the highest antibacterial activity, following cinnamon , clove and garlic has the least activity.Growth of Escherichia coli O157:H7 and Staphyloccus aureus were completely inhibited within 5 hours after addition of 1 % of garlic , 0.3% of ginger or cinnamon , 0.5% of clove powder on the exponential phase of the cells. Spice untreated cells of E. coli and S. aureus, the cytoplasm was entirely surrounded by rigid cell wall and cell walls formed a smooth layer well attached to the plasma membrane. In the cells of E. coli and S. aureus treated with spice powder, cell wall and plasma membrane were lysed and severely damaged. E.coli cells growth in the presence of spice powder showed plammolysis, the loss of electron dense material, the formation of extra cellular blebs and cytoplasm burst out from the cell. S .sureus cells grown in the presence of spice powder showed swell of cell wall, the loss of electron dense material , coagulation of cell cytoplasm and formation of extra cellular blebs. Severely damaged cells of S. aureus lost whole cytoplasm and left as ghost of the cell. Spice powder stimulated autolyssi and induced cell death.

• 한국재료학회지
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• 제9권11호
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• pp.1108-1111
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• 1999

결정성장 도중 전류에 의해 고/액 계면에서 발생하는 Peltier 열을 이용하면 온도구배의 증가와 이에 따른 성장속도의 증가 및 결정성의 향상에 기여할 것이라 예상되어, 고/액 계면에서 복합적으로 발생하는 Peltier 효과를 조사하였다. 전류 밀도, 극성 및 온도구배의 변화에 따른 고상과 액상 및 그 계면에서의 온도변화로부터 이론적 추론에 의해 Peltier 열, Thomson 열 및 Joule 열만의 영향으로 분류할 수 있었고, 고상/액상 계에 대한 Peltier 계수 및 Thomson 계수도 구할 수 있었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 춘계학술대회 논문집
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• pp.71-79
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• 1994

Strip drawing of strain-hardening, viscoplastic materials with damage is analyzed by a rigid plastic finite element method. A process model is formulated using two state variables, one for strain hardening from slip dominated plastic distortion and the other for damage from growth of microvoids. Application of the model to steady state drawing is given via implementation in a consistent penalty finite element formulation. The predicted density changes as a result of void growth are compared to those from experiments reported in the literature. The effects of drawing conditions such as drawing speed and die angle on the mechanical property changes are studied.

• Journal of Applied Biological Chemistry
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• 제49권4호
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• pp.176-179
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• 2006

Electron beam irradiation was applied to examine the microbial growth and qualities of vacuum-packaged Astragalus membranaceus, a Korean medicinal herb. Samples were irradiated at dose of 2, 4, 8, 12, and 16 kGy, respectively. Microbiological data on A. membranaceus showed that populations of total bacteria, yeast and mold, total coliforms were significantly reduced with increase of irradiation dose. Populations of microorganisms in A. membranaceus were decreased by 2-3 log cycles at 8 kGy irradiation. Color measurements showed that electron beam treatment caused negligible changes in Hunter color L, a, and b values of A. membranaceus. Sensory evaluations showed that there were no significant changes among the samples. These results suggest that electron beam irradiated A. membranaceus have better microbial safety and qualities, compared with the non-irradiated control.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1999년도 제16회 동계학술발표회 논문집
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• pp.328-347
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• 1999

The substitution of Electronic Commerce(EC) for the traditional transactions triggers the changes of the industry structures and promotes the cost reductions of the firms in the areas of distributions and other administrative operations associated with purchase via EC. Our study clarifies the changes of the environments attributable to EC which are faced inter-and-externally by firms and try to exhibit the trend of EC market growth through such descriptions. Regardless of the rapid spread of EC, recent studies do not show appropriately its impact on the relevant industries and our domestic economy. Therefore, our study focuses on the forecasting of the impacts of EC on the domestic productions and imports. To this end, we develop an analytic framework using the existing data in Input/Output Analysis and the estimations of the EC market growth in the future. We, finally, identify the industrial sectors whose productions and imports are estimated to be accelerated by the extension of EC and forecast the whole effects of EC on domestic productions and imports.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.375-378
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• 2008

This paper aims at identifying the factors that have influenced changes in the level of industrial $CO_2$ emissions. By means of complete decomposition method the observed changes are analyzed into five different factors: output level, energy intensity, energy mix and structural change and utility use. The application study refers to the manufacturing sectors in Korea. Moreover, this paper discusses the relationship between Korea's manufacturing $CO_2$ emission and economic growth (as measured by GDP), investigating whether economic growth is decoupling from $CO_2$ emission.

• 가정과삶의질연구
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• 제32권1호
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• pp.1-12
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• 2014

The purpose of this study was to examine: (1) whether the level of parental monitoring changes during adolescence; (2) if it changes, what is the pattern of the change; and (3) whether the effects of adolescents' attachment to their parents on parental monitoring are dependent on time. Six waves of data from the Korea Youth Panel Study (KYPS) were used to address the research questions. The participants of the KYPS were 3,449 (1,725 boys and 1,724 girls) adolescents who participated in the study once a year for 6 years (from the 2nd grade in middle school until their high school graduation). Latent growth modeling (LGM) was used to analyze the data. The findings are as follows: the level of parental monitoring significantly increased over the six waves of the study, and the adolescents' attachment to their parents was a time-dependent predictor of parental monitoring. The results indicate that the quality of adolescents' attachment to their parents is an important factor that makes a difference in the level of parental monitoring by, possibly, affecting the level of adolescents' disclosure to their parents.

• 한국해양공학회지
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• 제11권4호
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• pp.111-121
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• 1997

The spectral energy balance model is composed and the nonlinear interaction is approximated by the discrete interaction parameterization as in WAM model. The numerical results of durational limited growth test agree very well with those of the exact model, EXACT-NL. The response of a wave spectrum to a change in wind direction is investigated numerically for a sequence of direction changes 30$^{\circ}$ , 45$^{\circ}$ , 60$^{\circ}$ , 90$^{\circ}$ . The high frequency components relax more repidly to the new wind direction than the low frequency components and the relaxation process also depends on the wave age. For wind direction changes less than 60$^{\circ}$ , the coupling by nonlinear interaction is so strong that the secondary peak in input source distribution is counteracted by the negative lobe of the nonlinear interaction. For wind direction changes grater than 60$^{\circ}$ , a second independent wind-sea spectrum is generated in the new wind direction, while the old spectrum gradually decays as swell.