• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.588-594
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• 2013

Under the condition of Baader aging, the chemical composition variation and the influence of transformer oil aging on electrical properties such as dielectric loss factor and physic-chemical properties such as interfacial tension were studied in the aging precess. Moreover, the correlation between hydrogenated transformer oil electrical and physic-chemical properties and its chemical composition variation were also investigated. The results show that these parameters of physic-chemical and electrical properties of hydrogenated transformer oil relate to each other and have closed correlation with chemical composition.

• 한국수산과학회지
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• 제2권1호
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• pp.71-82
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• 1969

The present investigations were carried out with the purpose of making clear the fundamental features of the seasonal variations in chemical composition of the brown algae. Three species of samples, Ecklonia cava, Sargassum sagamianum and Hizikia fusiforme have been analyzed monthly for their contents of total ash, crude protein, alginic acid, mannitol, and laminarin over a year period. Three kinds of samples were collected from the same locality, situated on the southern coast of the Che-ju Island, from September 1966 to August 1967. In addition, the comparative analysis was made on fronds and stipes of the plant for their chemical composition. The results obtained are summarized as follows: 1, In general, the three species examined underwent a similar mode of seasonal variation, and no essential difference was detected among them. 2. The chemical composition of the plant exhibited a considerable difference between the species. The content of total ash in H. fusiforme was remarkably higher than those in the two other species respectively. The alginic acid content was relatively high in S. sagamianum and low in H. fusiforme. The contents of crude protein, mannitol and laminarin were appreciably high in E. cava and low in H. fusiforme in general. 3. The most outstanding feature in the seasonal variation was that, in general, the total ash, crude protein, and alginic acid contents were at a maximum in the winter months while laminarin and mannitol contents were at a minimum. The converse was true in summer. Total ash-Maximum values were observed from December to February and minimum from August till October. Crude Protein-All species exhibited maxima in January and February, and minima from August to October. Alginic acid-Maximum contents occured from January to March and minimum from September to November. Mannitol-The maximum content of mannitol was In May and lune and minimum in January, February and March. Leminerin-Maximum content was in September and October, and minimum in January and February. 4. The wide seasonal variation in chemical constitution occured in the fronds, but the stipes showed a slight seasonal variation. In the chemical composition, the stipe was high in alginic acid, low in mannitol and laminarin. The reverse was in the frond.

• 한국작물학회지
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• 제41권3호
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• pp.354-361
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• 1996

신속하고 정확한 근적외선 분광분석법으로 품질분석의 효율성을 증대하기 위하여 화학성분의 변이분포가 검량식 작성과정에 미치는 영향과 측정 정확성에 미치는 관계를 구명하여, 근적외선 분광광도계의 이용 효율성 제고를 위한 기초자료를 얻고자 실시한 실험의 결과는 다음과 같다. 1. 보리 전분에 대한추정치 표준오차는 변이폭이 증대될수록 증가하는 경향을 보였으며, 상관계수도 변이폭이 증대될수록 0.872에서 0.883으로 다소 높아지는 경향을 나타내었다. 2. $eta$-glucan과 단백질은 변이폭이 증대될수록 추정치 표준오차는 낮아지고 상관계수는 높아지는 결과를 보여, 근적외선 분광분석법의 이용성 향상을 위하여서는 이들 성분의 함량변이 확대가 필요할 것으로 생각되었다. 3. 회분은 첫번째와 두번째 group에서는 유의성이 인정되지 않았으나, 세번째 group에서는 상관계수가 0.743으로 유의성이 인정되어 회분함량의 경우에는 어느 정도의 변이폭이 있어야만 근적외선 분광분석법이 가능할 것으로 생각되었다. 4. 겉보리 성분 중 전분과 회분은 재검토가 이루어져야 할 것으로 생각되었으며, $\beta$-glucan과 단백질은 근적외선 분광분석법의 적용이 가능하여 분석의 효율성이 증대될 것으로 생각되었다.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.979-987
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• 2011

Culture pH change has some important roles in signal transduction and secondary metabolism. We have already reported that acidic pH shock enhanced actinorhodin production in Streptomyces coelicolor. Among many potential governing factors on pH variation, the putative $Na^+/H^+$ antiporter (sha) genes in S. coelicolor have been investigated in this study to elucidate the association of the sha on pH variation and secondary metabolism. Through the transcriptional analysis and overexpression experiments on 8 sha genes, we observed that most of the sha expressions were promoted by pH shock, and in the opposite way the pH changes and actinorhodin production were enhanced by the overexpression of each sha. We also confirmed that sha8 especially has a main role in maintaining cell viability and pH homeostasis through $Na^+$ extrusion, in salt effect experiment under the alkaline medium condition by deleting sha8. Moreover, this gene was observed to have a function of pH recovery after pH variation such as the pH shock, being able to cause the sporulation. However, actinorhodin production was not induced by the only pH recovery. The sha8 gene could confer on the host cell the ability to recover pH to the neutral level after pH variation like a pH drop. Sporulation was closely associated with this pH recovery caused by the action of sha8, whereas actinorhodin production was not due to such pH variation patterns alone.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1348-1350
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• 1999

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4207-4210
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• 2012

• Asian-Australasian Journal of Animal Sciences
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• 제16권2호
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• pp.172-175
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• 2003

The regression equations of dry weight of planktonic biomass upon physico-chemical characteristics of fifteen ponds in three replicates under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond was obtained after one year of experimental period by using stepwise regression method. Water samples from each of the ponds were analyzed daily. However, the average values were calculated on the basis of 15 day intervals designated as fortnight. In artificial feed supplemented pond the regression of average nitrates on dry weight of planktonic biomass accounted for 71.7% of the variation in biomass. In broiler manure fertilization pond the regression of total nitrogen on dry weight of planktonic biomass held it responsible for more than 74.6% of variation in biomass. In buffalo's manure fertilized pond more than 82% of the variations in biomass were due to total nitrogen. In case of N:P:K (25:25:0) treated pond 66% of the variation in the dry weight of planktonic biomass was due to average nitrates. The control pond showed the dependence of biomass on light penetration. This equation explained more than 62 percent of variation in biomass. Other variables also showed some contribution towards variation in biomass under all the treatments in these regression studies.

• Structural Engineering and Mechanics
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• 제70권5호
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• pp.525-534
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• 2019

An analytical research on buckling of simply supported thin plate with variable thickness under bi-axial compression is presented in this paper. Combining the perturbation technique, Fourier series expansion and Galerkin methods, the linear governing differential equation of the plate with arbitrary thickness variation under bi-axial compression is solved and the analytical expression of the critical buckling load is obtained. Based on that, numerical analysis is carried out for the plates with different thickness variation forms and aspect ratios under different bi-axial compressions. Four different thickness variation forms including linear, parabolic, stepped and trigonometric have been considered in this paper. The calculated critical buckling loads and buckling modes are presented and compared with the published results in the tables and figures. It shows that the analytical expressions derived by the theoretical method in this paper can be effectively used for buckling analysis of simply supported thin plates with arbitrary thickness variation, especially for the stepped thickness that used in engineering widely.

• 한국연초학회지
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• 제26권1호
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• pp.17-26
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• 2004

This study was conducted to get the informations for reducing the variation of chemical contents of leaf tobacco. The contents and variations of some chemical constituents of leaf(Leaf, Grade 2) produced in various growing areas from 1999 to 2003 and the effects of meteorological factors on the chemical constituents of leaf were analysed. The contents of analysed constituents of leaf showed high significant differences among crop years in flue-cured and burley, particularly the variation among crop years were higher in chlorine and nicotine contents while lower in total nitrogen content. There were significant differences among growing areas in nicotine and total sugar contents of flue-cured leaf and chlorine content of burley leaf. The total sugar content were negatively correlated to the nicotine and total nitrogen contents in flue-cured leaf. The average air temperature in June and July were positively correlated to the nicotine content of leaf while negatively to total sugar, and the precipitation in May were negatively correlated to the nicotine while positively to total sugar.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.677-679
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• 2013