• 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.

• 한국토양비료학회지
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• 제42권3호
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• pp.160-166
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• 2009

We estimated site productivity for unstocked land based on the relationship between site index (i.e., average height of dominant trees at fixed age) and soil physico-chemical properties of Pinus densiflora stands. Site index relates to a direct method of determining a tree's response to a specific environment such as forest soil and climate conditions. We selected 78 sites in 22 P. densiflora stands of central temperate forest zone, and sampled soils for physicochemical analyzing. And 13 properties of soils were statistically treated by stepwise regression. In the degree of contribution of the variables to site index, the highly effective variables in A horizon were OM, clay content, sand content, available $P_2O_5$, and Exch. $Ca^{{+}{+}}$ inorder, and in B horizon T.N., O.M., Soil pH, cation exchange capacity(C.E.C.), and sand content in order. In both A and B horizon of the soil for P. densiflora stands, the variables commonly contributed to the site index were sand content and OM. These results may be useful to provide not only important criteria for establishment of Pinus densiflora stand sespecially in unstocked land but also aguidance for reforestation.

• 한국응용곤충학회지
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• 제22권2호
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• pp.84-97
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• 1983

Under the limited arable land, the enhancement of agricultural productivity is indispensable to provide the food demand which is concomitant with the rapid increase in population. From this viewpoint, the upbringing and dissemination of high-yielding varieties has been promoted continuously and several modifications in cultural practices, including heavy fertilization, dense planting, and early transplanting, also have been gradually developed. However these changes in cultivation have led to the increased outbreak of insect pests and diseases. And this unexpected results have accelerated the number and complexity of pesticides employed as well as their consumption. Even though pesticides are essential materials contributing to the steady production of agricultural crops, large scale consumption of them has given rise to several adverse impacts, such as mammalian hazard and/or environmental contamination. In this respect, recent development of new pesticides has been concentrated on 'safe pesticide', as it were, that has the highly selective properties without unfavorable side influences on other ecosystem. According to literature cited up to now, feasibilities of safe pesticide development would be summarized as two categories. One of them is the development of chemical pesticides, which include the molecular structure modification of established pesticides for increased safety and synthesis of new safe chemicals which can attack the vulnerable point of physio-ecological characteristics in insect pests and diseases. The other is the biological pesticides which comprise natural enemies and microorganisms to act selectively on confined insect pests and diseases, In addition, improvement of physico-chemical properties of available pesticide formulations would be one of the desirable means for safe pesticide development in view of efficacy enhancement and minimization of hazardous properties or safe pesticide development, various approaches are feasible and needed to study, however, long period and much financial outlay are necessary to develop a new item. And under the present situation in Korea, there are many difficulties for performing research on all the possible routes. Therefore, combined pesticides by the reasonable combination of already registered resticides evaluated as the fairly safe pesticides and safe formulation based on their physico-chemical properties would be developed primarily. And many efforts would be given gradually for the development of new chemical and biological pesticides.

• 한국가금학회지
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• 제23권4호
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• pp.193-201
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• 1996

This experiment was carried out to find out the effect of packing methods on physico-chemical properties of breast and thigh meats in chicken, which was dried by air spray chilling method. The chicken carcass was cut into breast and thigh muscles, which were either vacuum packed or atmosphere packed, and stored at -2O˚C for 1, 4, 8, 12 and 16 wk after quick freezing at -45˚C for 35 min. The pH values of atmosphere-packed breast meat and vacuum-packed breast meat after one wk of storage were higher than those of atmosphere-packed thigh meat and vacuum-packed thigh meat(P< .05). The pH values increased as storage period extended, but no significant difference was detected between two packing method(vacuum vs. atmosphere). Total moisture contents of breast meats after one wk of storage were higher than those of thigh meats. The total moisture contents decreased slowly as storage period extended, but no significant difference was detected between two packing method(vacuum vs. atmosphere). The shear force value of thigh meat was higher than that of breast meat. The shear force values of both meats decreased as storage period extended, regardless of packing method. The water soluble protein extractability of thigh meats was higher than that of breast meat, and the water soluble protein extractability of all treatments decreased until 8 wk after storage, but increased gradually after 8 wk of storage period. The salt soluble protein extractability of breast meat was higher than that of thigh meat, and the salt soluble protein extractability of all treatments decreased as storage period extended. With regard to the packing method, the vacuum packing showed higher value than that of atmosphere packing method until 8 wk of storage. Total lipid contents of atmosphere- and vacuum-packed thigh meats at 1 wk of storage were higher than those of breast meats, and the total lipid contents of all of treatments decreased as storage period extended. However, no significant difference was detected between two packing methods. The fatty acid contents of breast and thigh meats were in order of o1eic(33,5~42.4), palmitic(19.7~30.8) and linoleic acid(10.8~17.4).

• 한국동물위생학회지
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• 제14권2호
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• pp.110-120
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• 1991

28 porcine enteroviruses were isolated from 86 pig-feces of 9 swine farms located in south region, Chung-buk, from March to September 1990. Physico-chemical properties and pathogenicity of isolates were investigated. Results obtained throughout experiments are summarized as follows. According to the age, weanlings(40-90 days), sucklings(10-30 days) and adult pigs(6 months over) showed the isolation rate of 67%. 8% and 4%, respectively. By physico-chemical tests, YD-90/22, YD-90/43 and YD-90/64 strains were found to be ether, chloroform and PH stable. Nucleic acid test suggests the virus to have a DNA genome. Most of the Isolates were not evident of hemagglutinin using erythrocytes from various mammalian & avian. 22 strains among the isolates were shown CPE type I and the remainders were CPE type II. 3 strains among isolates of CPE type I strains were neutralized with high titers to serotype 2 antiserum. In the study on virus growth curve in PK-l5 cells, YD-90/22, YD-90/43 and YD-90/64 strains showed the maximum infectivity titers($10^{6.0}-l0^{6.5} TCID({50}ml$) at 4days post inoculation(PI). When 30 day-old commercial piglets were inoculated only intraoral route with the YD-90/22 strain at $10^{6.0} TCID_{50}ml,$ piglets not showed the symptoms. But piglets inoculated by intramuscle route, intraoral and intramuscle route after pretreat with dexamethasone(2.5mg /kg) for 5 days were shown the symptoms of anorexia, diarrhea, pyrexia and ataxia at 4th-6th days PI. The viral reisolation in the virus-inoculated piglets was examined from feces. The viruses were recovered intermittently from 2nd to 16th day PI and at 4th-6th day PI, all piglets excreted viruses.

• 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.

• 한국축산식품학회지
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• 제23권1호
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• pp.16-20
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• 2003

본 연구는 쑥 분말을 돼지 사료에 첨가하여 0, 1, 3%의 비율로 비육후기 30일간 급여한 후 도축하여 4$^{\circ}C$에서 7일간 저장하면서 이화학적 특성에 대한 연구를 수행하였다. 대조구에 비하여 처리구(T1, T2)에서 조지방 함량이 약간 낮은 경향이었다. pH와 TBARS는 대조구에 비하여 처리구에서 유의적으로 낮았다. 저장기간이 경과함에 따라 pH, TBARS, VBN와 보수력은 증가하는 경향을 나타내었다(p<0.05). 돈육의 주된 지방산은 oleic acid, palmitic acid, linoleic acid와 stearic acid이었다. 처리구는 대조구에 비하여 linoleic acid와 linolenic acid 함량이 높은 경향이었다.

• 한국식품과학회지
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• 제12권4호
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• pp.324-327
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• 1980

비자유(榧子油)의 물리화학적 특성을 조사한 결과는 다음과 같이 요약될 수 있다. 1) 일반분석치는 수분 12.33%, 조단백질 9.46%, 조지방질 54.29%, 섬유소 5.28%, 회분 2.13%로서 조지방 함량이 대단히 높음을 알 수 있다. 2) 비자유(榧子油)의 비중은 0.92, 굴절율은 1.47, 요드값은 127, 비누화값은 182.2, 산값은 9.5, 에스테르값은 172.7이었다. 3) 지방산의 조성은 미리스트산, 팔미트산, 스테아르산, 아라키드산 등의 포화지방산이 10%이하이며, 불포화지방산 인 올레산 31.68%, 리놀레산 46.77%, 리놀렌산 0.38%로서 리놀레산의 함량이 높고 리놀렌산은 대단히 적었다.

• Advances in environmental research
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• 제7권2호
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• pp.139-159
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• 2018

Green Leaf Volatiles (GLVs) is a class of biogenically emitted oxygenated hydrocarbons that have been identified as a potential source of Secondary Organic Aerosols (SOA) via aqueous oxidation. The physico-chemical properties of GLVs are vital to understanding their fate and transport in the atmosphere via fog processing, but few experimental data are available. We studied the aqueous solubility, 1-octanol/water partition coefficient, and Henry's law constant ($K_H$) of five GLVs at $25^{\circ}C$: methyl jasmonate, methyl salicylate, 2-methyl-3-buten-2-ol, cis-3-hexen-1-ol, and cis-3-hexenyl acetate. Henry's law constant was also measured at temperatures and ionic strengths typical of fog. Experimental values are compared to scarcely-available literature values, as well as estimations using group and bond contribution methods, property-specific correlations and molecular dynamics simulations. From these values, the partition coefficients to the air-water interface were also calculated. The large Henry's law constant of methyl jasmonate ($8091{\pm}1121M{\cdot}atm^{-1}$) made it the most significant GLV for aqueous phase photochemistry. The HENRYWIN program's bond contribution method from the Estimation Programs Interface Suite (EPI Suite) produced the best estimate of the Henry's constant for GLVs. Estimations of 1-octanol/water partition coefficient and solubility are best when correlating an experimental value of one to find the other. Finally, the scavenging efficiency was calculated for each GLV indicating aqueous phase processing will be most important for methyl jasmonate.

• 한국수산과학회지
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• 제5권2호
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• pp.57-62
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• 1972

잉어의 배육 골격근에서 actomyosin을 추출하여 몇 가지 생물물리화학적인 성질을 측정 검토한 결과는 다음과 같다. 즉, actamyosin의 침강 정수($s_{20},\;_\omega$)는 24.76s이고 그 점성은 단백 농도의 증가와 더불어 급상승하여 다른 actomyosin의 그것과 비숫한 경향을 보였다. 그리고, ATP-sensitivity는 $147\~176$이었고, PH영향하에서 ATPase activity는 산성측이 6,0부근, 알칼리성측이 9.5부근이었으므로 ATPase activating site가 산, 알칼리 양측에 있음을 알았다.