• 한국가금학회지
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• 제25권2호
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• pp.55-64
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• 1998

This study was carried out to investigate the postmortem changes in physico-chemical characteristics of chicken meat with different breeds. Thigh and breast meats from Korean Native Chicken(KNC, 15-wk old), Wangchoo(15-wk old), and broiler(7-wk old) were stored at 5 ˚C. Differences in postmortem pH changes were not recognized among breeds, and pH showed by the lowest value at the 1st day of postmortem in all breeds. Breast meat had tendency to drop pH faster than thigh meat. Heme pigment contents showed no differences among breeds. KNC showed the lowest cholesterol contents in all breeds, total collagen contents showed the lowest value at the 1st day of postmortem, and thereafter it was gradually increased. Heat soluble collagen contents was lowest in Wangchoo. Water soluble and salt soluble protein showed the lowest extractability at the 1st day of storage. Broiler showed the highest extractability of these proteins and Wangchoo showed the lowest. Water holding capacity(WHC) had increasing tendency whilst cooking loss had decreasing tendency by the ageing. WHC of breast and thigh meat showed the highest values in KNC and broiler, respectively. Myofibrillar fragmentation index (MFI) was significantly increased in all breeds by the ageing. Breast and thigh meat showed almost same MFI in KNC and broiler, and in KNC and Wangchoo, respectively. Hardness of breast meat showed decreasing tendency by the ageing.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2897-2902
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• 2010

Seven fully optimized geometries of 3,6-dihydrazino-1,2,4,5-tetrazine (DHT) dimers have been obtained with density functional theory (DFT) method at the B3LYP/$6-311++G^{**}$ level. The intermolecular interaction energy was calculated with zero point energy (ZPE) correction and basis set superposition error (BSSE) correction. The greatest corrected intermolecular interaction energy of the dimers is $-23.69\;kJ{\cdot}mol^{-1}$. Natural bond orbital (NBO) analysis is performed to reveal the origin of the interaction. Based on the vibrational analysis, the changes of thermodynamic properties from the monomers to dimer with the temperature ranging from 200.0 K to 800.0 K have been obtained using the statistical thermodynamic method. It was found that the hydrogen bonds dominantly contribute to the dimers, while the binding energies are not only determined by hydrogen bonding. The dimerization process can not occur spontaneously at given temperatures.

• 한국식품위생안전성학회지
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• 제6권1호
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• pp.49-56
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• 1991

인삼 엽록차의 위생화를 위한 화학 훈증제 처리 및 감마선 조사가 시료의 몇가지 이화학적 특성에 미치는 영향을 조사하였다. 녹차의 품질에 관련된 가용성분, 사포닌 및 탄닌성분은 상업적 조건 ethylene oxide 처리와 10kGy 까지의 감마선 조사에 대하여 안정하였다. 그러나 비타민 C 및 클로로필은 5kGy 이상 조사와 훈증 처리시에 유의적으로 감소되었고, 녹차의 휘발성 성분, 추출액의 색도 및 pH는 살균선량 범위인 5kGy 조사군에 비해 훈증처리군에서 변화가 심하게 나타났다 .

• 약학회지
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• 제37권2호
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• pp.198-203
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• 1993

Physico-chemical properties of methyl 5-hydroxy-dinaphtho[1,2-2',3'] furan-7,12-dione-6-carboxylate(MHDDC) were examined. The yellowish color of the solution at pH 8 below changes to a bluish color when the solution is basified to pH 10 above. This color change was presumed to a change of the molecular structure from a quinoid-type to a quinoid-type with the dissociation to the hydroxyl group as shown in chart 1.

• 한국환경농학회지
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• 제29권4호
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• pp.354-361
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• 2010

Soil physico-chemical properties and microbial densities are affected by organic sources and soil amendment applied to improve soil environments or quality. Generally organic fertilizer effects on forage crops yield and soil properties are partly due to changes of soil composition. We investigated the effects of swine slurry (SS), swine slurry composting-biofilteration(SCB) and chemical fertilizer(F) with gypsum(G) combinations on soil physico-chemical properties and yields of summer forage crop in the Sukmoon reclaimed tidal land in Korea. The forage crops used in this experiment were corn and sorghum$\times$sudangrass hybrid(hereafter sorghum). Our results showed that the soil physico-chemical properties in the combined (F+G, SS+G, SCB+G) treatments increased contents of organic matter and exchangeable $Ca^{2+}$, but exchangeable $Na^+$, $K^+$ and $Mg^{2+}$ reduced to 1-10% for two forage crops, compared to non-combined (F, SS, SCB) treatment. The density of soil microorganism such as bacteria, actinomycetes and fungi, increased significantly by SS+G and SCB+G treatments. This means that treatment of combined organic fertilizer with G lowered salinity levels and improved with microbial growth. The combined treatments also increased the total yields 2.3-6.2% for corn and 2.0-8.7% for sorghum, compared with non-combined treatment. This experiment suggests the combined treatments could increase the total yields of summer forage crops and change of soil physico-chemical properties in the Sukmoon reclaimed tidal land in Korea.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.984-990
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• 2014

Polymers are the most commonly used di-electrics because of their reliability, availability, ease of fabrication and cost. The commercial and industrial demand for advanced polymeric materials which are capable of being used in harsh environment is need of the hour. The study of the effect of electron beam irradiation on polymeric materials is an area of rapidly increasing interest. This paper discusses the resultant beneficial effects of electron beam irradiation on the SiR-EPDM blend having 50:50 composition. The changes in mechanical and electrical properties of SiR-EPDM blend which are exposed to three different doses of electron beam radiation namely 5 Mrad, 15 Mrad and 25 Mrad are presented. The irradiated blends are analyzed for their electro-mechanical and physico chemical properties. The electrical changes induced by irradiation are investigated by arc resistance, surface resistivity and volume resistivity measurements as per ASTM standards. The mechanical changes are observed by the measurement of tensile strength and elongation at break. Physico chemical investigation has been done using the FTIR, in order to investigate the irradiation induced chemical changes.

• 환경위생공학
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• 제13권3호
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• pp.128-132
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• 1998

In this study, water quality characteristics of lakes in the Seosan area are analyzed. Components water quality were analysed at 10 sampled points in each lakes, and the results were evaluated for seasonal variation. It was found that water quality was over II~III class. Most of lakes in the Seosan area which implies that are suitable as the maintenance water. The concenturation of T-N, T-P was observed IV~V class during all seasons. Particularly, T-N concenturation peaks in spring, while was lowered in other seasons. In the lake, high concenturation of T-N, T-P bring about Eutrophication when algae was growth causing various physico-chemical changes in the water. It is suggested that the water quality management strategies need to be applied for each lake.

• 한국초지조사료학회지
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• 제11권1호
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• pp.22-29
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• 1991

This study was experimented to obtain the basic information on the changeable aspect and improvement of soil fertility in newly-reclaimed sloped land. Silage corn was cultivated under the six different treatments for 4 years. The relation between the amount or ratio of annual changes of soil physico-chemical properties and yield of silage corn were analyzed. Soil bulk density was decreased in 3rd year at topsoil, but that decreased in 4th year at subsoil. Soil organic matter also decreased in 2nd year at topsoil, and decreased continuously at subsoil. Bulk density and hardness of soil depths showed significant negative simple correlation with dry matter yield and cation exchange capacity showed positive. Correlation coefficient of chemical properties with dry matter yield were low. The range of annual changes of moisture percent, hardness and organic matter were wider than the other properties. The significantly different of physical properties were higher than the chemical properties, and those of topsoil were higher than subsoil. According to multiple regression between yield and physico-chemical properties of subsoil, bulk density and cation exchange capacity were in the greatest contribution at the variations, but bulk density was greatest at the ratios.

• 한국연초학회지
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• 제22권2호
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• pp.143-150
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• 2000

This study was carried out to investigate the effect of storage period on the physico-chemical properties of tobacco leaves expanded by $CO_2$. The flue-cured and burley tobacco leaves produced from 1996 to 1999 were processed, and stored for that year or 3 years in processing plant. As compared with 1996 crop, the expanded rate of flue-cured tobacco leaves in 1999 crop was higher approximately 18%, while that of burley was higher about 10%. The filling capacity of cigarettes was decreased as storage time became shorter, but the combustibility was improved. The rate of large particles (over 3.36mm) of expanded tobacco showed decreasing tendency as the storage period became longer. The change rate of chemical contents in tobacco leaves between before and after expansion had no significant difference among corp years. The tar and CO contents of cigarettes smoke were reduced in the case of flue-cured tobacco leaves as storage time became shorter, while they were slightly increased in the case of burley tobacco leaves. The ammonia content of burley leaves was decreased remarkably in 1996 and 1999 crop.

• 한국식품조리과학회지
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• 제14권2호
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• pp.177-181
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• 1998

감자 및 닭튀김의 튀김회수에 따른 튀김유의 물리화학적 특성의 변화를 경시적으로 측정하였다. 튀김유의 온도변화는 닭튀김의 경우보다 감자튀김의 경우 더 큰 것으로 나타났다. 튀김과정 중에 튀김재료인 냉동감자의 중량감소는 21.9% 정도이었으며 닭튀김의 경우 닭튀김물의 중량감소는 12.8% 정도인 것으로 나타내었다. 튀김횟수인 15회까지의 감자 튀김유와 닭튀김유의 산가는 튀김횟수에 따라 지속적으로 증가하였으며 이들의 산가는 모두 0.6이하로 나타났다. 튀김횟수인 15회까지의 감자와 닭튀김유의 과산화물가는 일률적으로 증가하지 않았다. 튀김횟수에 따른 감자와 닭튀김유의 요오드가의 변화는 거의 보이지 않았다. 감자 및 닭튀김시 튀김유의 색상은 튀김횟수가 증가함에 따라 R(red)및 Y(yellow)가 뚜렷이 증가되었으며, 닭튀김유는 감자튀김유보다 훨씬 높았다. 튀김횟수가 증가함에 따라 linoleic acid의 감소와 oleic acid의 상대적인 증가를 나타내었다. Linoleic acid의 감소와 oleic acid의 증가는 감자튀김유보다는 닭튀김유에서 더욱 큰 것으로 나타났다.