• 한국산학기술학회논문지
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• 제18권2호
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• pp.226-234
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• 2017

본 논문에서는 경량기포 콘크리트에 EPS 폐기물과 난연성 EPS 폐기물 보강재를 각각 혼입해 물성 특성을 연구하였다. 물시멘트비는 50%로 고정시켰으며 단위시멘트량은 300, $400kgf/m^3$으로 설정하였다. 독립기포용 기포제를 사용하였고, 희석농도는 10%로 설정하여 혼합하였다. 혼입률은 0, 10, 20, 30, 40%로 혼입하였으며, 선 기포 방식으로 제조하였다. 상기 배합조건 별로 제작된 경량기포 콘크리트 시험체의 겉보기 밀도, 휨강도, 열전도율 및 흡수율을 측정하고 분석하였다. 실험결과, 겉보기 밀도는 단위시멘트량에 관계없이 2~3% 내외의 차이를 보였고 각각 KS F 4039 겉보기 밀도의 0.5품, 0.6품을 만족시켰다. 휨강도는 압축강도를 통해 치환하여 압축강도 기준 0.4품, 0.5품, 0.6품을 만족 시켰으며, 열전도율은 난연성 EPS 폐기물 보다 EPS 폐기물이 보강재일 경우가 3~5% 정도 높게 나왔지만 두 보강재 모두 KS F 4039 0.4품 기준을 만족하였다. 흡수율 측면에서는 EPS 폐기물과 난연성 EPS 폐기물 보강재를 혼입한 경우 1~3%정도의 차이를 보였지만 모두 20%가 넘는 높은 수치를 보여 추가적인 보강재나 배합비가 필요할 것으로 판단된다.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 Proceedings of the 17th Symposium on Plant Biology Environmental Stress and Photosynthesis
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• pp.68-82
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• 1999

CHilling tolereance of plants are closely correlated with the degree of fatty acid unsaturation of membrane lipids. We studied the effects of low-temperature photoinhibition on the photochemical efficiency of photosystem II in terms of fatty acid unsaturation of thylakoid membranes lipids isolated from chilling -sensitive plants and chilling -resistant ones. To directly test the chilling tolerance of photosynthetic machinery in relation to membrane lipids, we further compared wild type tobacco plants with that of transgenic tobacco plants, in which the sensitivity to chilling had been enhanced by genetic modification of fatty acid unsaturation of chloroplast membrane lipids. The transgenic tobacco plants were found to contain reduced levels of unsaturated membrane fatty acids after being transformed with cDNA for glycerol-3-phophate acyltransferase from squash. The functional integrity of photosystem II during and recovery of photosynthesis from low-temperature photoinhibition will be discussed in connection with the degree of fatty acid unsaturation of chlorophast membranes lipids.

• 대한미생물학회지
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• 제14권1호
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• pp.49-61
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• 1979

Two hundred and ninety-five strains of Peudomonas aeruginosa isolated from clinical sources were tested for drug resistance and demonstration of R plasmids by intraspecies conjugation system. Sixty strains were found highly resistant to two or more of drugs. The rate of resistant strains were 38.9% to kanamycin(km), 33.2% to streptomydn(sm), 22.7% to sulfisomidine(Sa), 14.2% to chloramphenicol(Cp), 13.8% to tetracycline(Tc), 3.0% to carbenicillin(Cb), and to gentamicin(Gm), respectively. But no strains was resistant to nalidixic acid and colistine. They were resistant to per milliliter to more than $400{\mu}g$ per ml. of Tc, $800{\mu}g$ per ml of Cp and of Sm, $6,400{\mu}g$ per ml. of Sa, $200{\mu}g$ per ml. of Cb, $100{\mu}g$ per ml. of Gm, and $25{\mu}g$ per ml. of colistine. Forty-three strains of Pseudomonas aeruginosa could be transferred their resistance to Pseudomonas aeruginosa 2-70, 1005 rifampin resistant FP-auxotrophic mutant. Of sixty multiple resistant strains, forty-three(71.6%) demonstrated R plasmids; nineteen carried resistance to(Tc Cp Sm Sa), six to(Tc Cp Sm), three to(Tc Cp Sa), and Cp, five to(Tc Sm Sa), two to(Tc Sa), (Cp Sm) and Tc, and one to(Cp Sm Sa). Degree of resistance of recipients recieving R plasmids from donors were almost the same level of resistance as the donor in regardless of mating temperature at $25^{\circ}C$ and $37^{\circ}C$. Resistance to Tc, Sm, and Sa were transferred to a very few of recipient cells at five minutes after mating with donor and recipient cells but resistance to Cp were transferred to the majority of recipient cells. The transfer frequency of Tc, Cp, Sm, and Sa resistance from donors to recipients were from $1.0^{-1.4}\;to\;1.0^{-3.5}$ at $25^{\circ}C$ for 18 hours of incubation and were from $1.0^{-1.5}\;to\;1.0^{-3.5}$ at $37^{\circ}C$ for 18 hours of incubation.

• 한국초지조사료학회지
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• 제33권2호
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• pp.111-116
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• 2013

본 시험은 사료용 옥수수의 검은줄오갈병에 대한 저항성 품종을 선발하기 위하여 2006년부터 2008년까지 전라북도 고창에서 수행하였다. 국내외 사료용 옥수수 10품종을 1모작과 2모작으로 재배하여 품종에 따른 검은줄오갈병의 이병률과 수량성을 조사하였다. 그 결과 사료용 옥수수 품종에 따른 검은줄오갈병의 발병률이 차이가 있는 것으로 나타났다 (p<0.05). 검은줄오갈병에 대한 저항성의 정도를 4개의 그룹으로 분류하면, 매우 강한 그룹은 '광안옥'과 '광평옥', 강한 그룹은 'P3156'과 'P3394', 중간 그룹은 '청안옥'과 'P32P75', 약한 그룹은 'NC7117', '수원 19호' 'DK697' 및 'GW6959' 품종이었다. 검은줄오갈병 발생에 따른 사료용 옥수수의 건물수량은 품종 간에 차이가 있었으며 (p<0.05), 검은줄오갈병 저항성 품종인 '광안옥', '광평옥', 'P3156' 및 'P3394' 품종은 이병성 품종보다 건물수량이 14~26% 많았다. 따라서 검은줄오갈병 발생이 심한 지역에서 옥수수 재배를 할 때는 반드시 저항성 품종을 선택하는 것이 중요하다.

• 식물병연구
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• 제30권2호
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• pp.124-130
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• 2024

Stemphylium vesicarium에 의해 발병하는 잎마름병은 마늘재배에 있어 전 세계적으로 가장 중요한 곰팡이 병 중 하나이며, 종자의 품질과 수확량을 감소시킨다. 병 저항성 품종의 재배는 화학 농약의 사용을 감소시키고, 작물 손실을 최소화하는 데 효율적인 방법이다. 본 연구는 잎마름병 저항성 마늘 유전자원을 발굴하기 위하여, 20점의 마늘 유전자원의 잎마름병에 대한 저항성을 조사하기 위하여 실험하였다. 온실에서 재배한 4엽기 유묘의 잎을, 접종 직전에 탈지하지 않은 비흡수성 재질의 솜으로 문지른 후에 멸균한 1/2 농도의 PDB 용액으로 수확한 S. vesicarium KACC 44530 균주의 포자현탁액(3.0×10⁵ spores/ml)을 분무하여 접종하였다. 그리고 접종 3-7일 후에 잎에 발생한 잎마름병의 병반면적률(%)을 조사하였다. 이때 저항성 및 감수성 대조 품종으로 '남도'와 '대서' 마늘이 사용되었다. 실험한 유전자원 중에서, IT245512, IT245528 및 IT244068은 잎마름병에 가장 높은 저항성을 보였으며, 유전자원 IT257134와 IT253043은 잎마름병에 대하여 가장 높은 감수성을 나타내었다. 본 연구에서 선발한 저항성 유전자원은 잎마름병 저항성 육종 시스템에 유용한 자원으로 이용될 수 있을 것이다.

• 농업과학연구
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• 제45권4호
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• pp.779-787
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• 2018

The objective of this study was to investigate the structural and physicochemical properties of starch by barely cultivars. Hwanggeumchal had a moisture content and ${\beta}$-glucan content of 12.02 and 6.23%, respectively. Hyegang had higher protein contents than those of the other cultivars. As a result of observing the particle size of starch, Hwanggeumchal and Hyegang had smaller particles of starch compared with the other cultivars at 15.7 and $15.9{\mu}m$, respectively. The analysis results on the content of damaged starch showed that Dahan and Hyegang had a damaged starch content of 1.14 and 1.20%, whereas Boseokchal and Hwanggeumchal were 0.76 and 0.49% respectively, showing low waxy cultivars. As for the content of amylose, the results show that Dahan and Hyegang had an amylose content of 37.07 and 37.75%, and Boseokchal and Hwanggeumchal were at 11.22 and 37.75%, respectively. As for the degree of amylopectin polymerization, all four cultivars had the highest degree of polymerization (DP) content of 13 - 24 at more than 54%, whereas the DP content ${\geq}37$ was the lowest at less than 5.35%. The results for the soluble and resistant starch content show that the content of soluble starch ranged from 93.90 to 95.76%, and resistant starch was 0.17 - 0.40%. After analyzing the gelatinization properties of barley starch, the value of the setback was low in Hwanggeumchal and Hyegang; thus, it is considered that the aging process of those cultivars will be slower than that of the others.

• The Plant Pathology Journal
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• 제20권2호
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• pp.110-114
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• 2004

Through in vitro screening for biocontrol agents (BCAs) against Streptomyces scabiei causing potato (Solanum tuberosum) common scab, 19 streptomycete and 17 fungal isolates with antagonistic activity were selected as BCA candidates. For the selection of BCA candidates which are highly resistant to 10 kinds of antibiotics or pesticides, chemical susceptibility testing was initially performed in vitro. A remarkable degree of variation in susceptibility to antibiotics or pesticides was observed among the isolates tested. Streptomycete A020645 isolate was highly resistant to all the tested chemicals except neomycin up to 5,000 ppm. On the other hand, out of 36 antagonistic microbes subjected to in vivo pot tests using cultivar Daejima, four streptomycete isolates namely, A020645, A010321, A010564, and A020973, showed high antagonistic activity with >60% and 55% control value, respectively, and high chemical resistance to 10 kinds of chemicals. Therefore, these isolates were selected as potential BCAs for the control of potato common scab.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권3호
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• pp.211-217
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• 2004

Previously, strains of Streptococci genera were isolated from osteomyelitis caused by the post-infection after extraction. In present study, to test the sensitivity of the Streptococci strains against seven antibiotics, penicillin G, amoxicillin, tetracycline, ciprofloxacin, cefuroxime, erythromycin, clindamycin, and vancomycin, minimum inhibitory concentration (MIC) was performed using broth dilution assay. Our data showed that the value of MIC of the Streptococci against antibiotics were different among the strains. In addition, the degree of resistance to antibiotics of Streptococci strains was mainly depended on the origin of isolation. Our results suggest that the development of the rapid and accurate method to detect the antibiotics-resistant bacteria is need to prevent the misuse or abuse of antibiotics and outbreak of antibiotics-resistant bacteria.

• Earthquakes and Structures
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• 제9권5호
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• pp.1091-1114
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• 2015

The adequacy of a number of advanced earthquake Intensity Measures (IMs) to predict the structural damage of earthquake resistant 3D R/C buildings is investigated in the present paper. To achieve this purpose three symmetric in plan and three asymmetric 5-storey R/C buildings are analyzed by nonlinear time history analysis using 74 bidirectional earthquake records. The two horizontal accelerograms of each ground motion are applied along the structural axes of the buildings and the structural damage is expressed in terms of the maximum and average interstorey drift as well as the overall structural damage index. For each individual pair of accelerograms the values of the aforementioned seismic damage measures are determined. Then, they are correlated with several strong motion scalar IMs that take into account both earthquake and structural characteristics. The research identified certain IMs which exhibit strong correlation with the seismic damage measures of the studied buildings. However, the degree of correlation between IMs and the seismic damage depends on the damage measure adopted. Furthermore, it is confirmed that the widely used spectral acceleration at the fundamental period of the structure is a relatively good IM for medium rise R/C buildings that possess small structural eccentricity.

• Steel and Composite Structures
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• 제30권4호
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• pp.351-364
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• 2019

Earthquake and fire are both severe disasters for building structures. Since earthquake-induced damage will weaken the structure and reduce its fire endurance, it is important to investigate the behavior of structure subjected to post-earthquake fire. In this paper, steel-concrete composite beam-to-column joints were tested under fire with pre-damage caused by cyclic loads. Beforehand, three control specimens with no pre-damage were tested to capture the static, cyclic and fire-resistant performance of intact joints. Experimental data including strain, deflection and temperature recorded at several points are presented and analyzed to quantify the influence of cyclic damage on fire resistance. It is indicated that the fire endurance of damaged joints decreased with the increase of damage level, mainly due to faster heating-up rate after cyclic damage. However, cracks induced by cyclic loading in concrete are found to mitigate the concrete spalling at elevated temperatures. Moreover, the relationship between fire resistance and damage degree is revealed from experimental results, which can be applied in fire safety design and is worthwhile for further research.