• Research in Plant Disease
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• v.30 no.2
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• pp.131-138
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• 2024

The effects of five fungicides on the spore growth phase of Alternaria dauci, which causes carrot leaf blight, were tested using the spore viability assay (SVA) and agar dilution method (ADM). The average EC₅₀ values for chlorothalonil against seven isolates of A. dauci examined by SVA and ADM were 14.21 ㎍/ml and more than 100 ㎍/ml. Dithianon and folpet also had lower EC₅₀ values in SVA than in ADM, while iminoctadine trisalbesilate had lower EC₅₀ value in ADM. For fluazinam, the EC₅₀ values of SVA and ADM were 1.63 and 2.40 ㎍/ml, respectively. As EC₅₀ values of five fungicides according to the spore growth phase of A. dauci KACC 42997, the efficacy of each fungicide as chlorothalonil, dithianon, and folpet decreased when treated after spore germination rather than when treated with spores before germination. However, iminoctadine tris-albesilate was more effective when treated after spores germinated than when treated before treatment. The excellent effect of fluazinam on the pathogen was maintained until A. dauci KACC 42997 was cultured in potato dextrose broth for 6 hr and the germ tube grew beyond the size of the spore. However, when treated with iminoctadine tris-albesilate and fluazinam after culturing for 12 hr, as the EC₅₀ values of the two fungicides increased to 8.87 and 20.65 ㎍/ml, their efficacies decreased. The results of this study show that the treatment time of the fungicide should be determined by considering the effect of the fungicide on the spore growth phase of pathogens.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.301-310
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• 1994

This experiment was conducted to test the fungicidal activity of extracts from 50 medicinal plants to powdery mildew (Sphaerotheca fulinginea) and identify the bioactive substances. Among the medicinal plants tested, the water extract of Rheum undulatum was the most effective in spore germination inhibition, which inhibited by 100% at 200-fold dilution. Also, 50-fold dilution of water extract, 100-fold dilution of alcohol extract, 500-fold dilution of crude extract from Rheum undulatum and even 1000-fold dilution of reference chemical inhibited powdery mildew of cucumber more than 60%. 500-fold dilution of crude extract inhibited powdery mildew of cucumber 100% by twice spray treatment. There was phytotoxcity at the 100-fold dilution, but was not recognized this injury at the 500-fold dilution of crude extract. From our research to identify bioactive substance using HPLC, GLC and Mass spectrum analysis, it indicated that Rheum undulatum extract contained tentatively 1,8-dihydroxy-3-methyl-9,10-anthracenedione and 1,8-dihydroxy-3-methoxy-6-methyl-9,10-anthracenedione.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.7
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• pp.275-282
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• 2016

MILD (Moderate and Intense Low-oxygen Dilution) combustion using oxygen as an oxidizer is considered as one of the most promising combustion technologies for high energy efficiency and for reducing nitrogen oxide and carbon dioxide emissions. In order to investigate the effects of nozzle angle and oxygen velocity conditions on the formation of oxygen-MILD combustion, numerical and experimental approaches were performed in this study. The numerical results showed that the recirculation ratio ($K_V$), which is an important parameter for performing MILD combustion, was increased in the main reaction zone when the nozzle angle was changed from 0 degrees to 15 degrees. Also, it was observed that a low and uniform temperature distribution was achieved at an oxygen velocity of 400 m/s. The perfectly invisible oxy-MILD flame was observed experimentally under the condition of a nozzle angle of $10^{\circ}$ and an oxygen velocity of 400 m/s. Moreover, the NOx emission limit was satisfied with NOx regulation of less than 80 ppm.

• The Korean Journal of Mycology
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• v.41 no.4
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• pp.274-279
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• 2013

Slightly acidic hypochlorous water (SAHW) is well known for having a powerful and broad spectrum antimicrobial activity, and is harmless to the environment and humans. SAHW (pH 5~6.5, 20~30 ppm available chlorine concentration) was generated by electrolysis of dilute solution of HCl (4%) in a chamber of a non-membrane electrolytic cell. Our objective was to determine SAHW has a potential fungicidal activity on some phytopathogenic fungi. Spores of Botrytis cinerea, Colletotrichum acutatum and Phytophthora capsici were not culturable on agar media at approximately 10 seconds after treatment by SAHW. However, inactivation of Penicillium hirsutum was required over 3 min. Dilution of SAHW with sterilized distilled water (SDW) at the ratio of 1:1 (SAHW:SDW) against C. acutatum showed 100% inactivation but, the efficacy in 1:2 decreased until 63.2%. Control value of SAHW was 70.4% against C. acutatum on pepper fruits when applied upto 24 h postinoculation. SAHW has a powerful and wide spectrum antifungal activity and could be applied as a potential alternative to fungicidal agent for control of plant disease.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.842-849
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• 2015

This study investigated the effects of rare-earth fertilizer on the shoot cuttings' rooting of Vitex rotundifolia L. and Tamarix chinensis Lour. The shoot cutting test was carried in 2008 and the main results are summarized as follows. The rate of rooting and the average roots increased in both number and length when rare-earth fertilizer is treated in V. rotundifolia and T. chinensis in comparison to those of the untreated control plot. In particular, when rare-earth fertilizer is diluted with water 1/2500, the rooting outstandingly increases. This result is almost similar to the effect of the rooting stimulant, IAA. Although there is no differentiation in its rooting rate according to the density, the rooting of T. chinensis shows a 100 percent effect on in the entire treated plot but not in the untreated control plot, so it is usable as a rooting stimulant. As for shoot cuttings' rooting, depending on the time immersed in diluted solution of rare-earth fertilizer, both V. rotundifolia and T. chinensis showed relatively higher percentages in all treatment plot immersed for 60 minutes than for 10 minutes. In conclusion, considering the results of the rooting percentage and the average number and length of roots of V. rotundifolia and T. chinensis, the shoot cuttings' rooting appeared higher in percentage when they were immersed in the rooting stimulant for sixty minutes with a lower density than 1/2500. This result shows that rare-earth fertilizer can be utilized as an alterative for IAA rooting stimulants currently available in the market.

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.241-252
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• 1997

본 연구는 임상검사 및 방사선 사진상 악관절장애로 진단된 환자중 물리치료,악관절 안정장치 등의 보존적 치료방법을 시행하였으나 증상의 개선이 별로 없는 퇴행성 관절질환이나 중등도의 개구제한을 가진 환자를 대상으로하여 aspirin을 이용한 활액성분 분석 및 악관절 도약술과 sodium hyaluronate의 주입을 시행한후 이에 따른 치료결과를 평가하기 위하여 시행되었다. 평균연령이 31.2세(21-42세)인 11명의 악관절 장애환자를 대상으로 하였다. 악관절 도약술과 sodium hyaluronate의 주입은 악관절의 동통과 개구제한의 해소를 위해 시행되었으며 그 결과를 시술전, 시술 즉시, 시술 1주후 및 4주후로 나누어 분석하였으며 활액 채취시 생리식염수의 희석에 의한 활액성분의 농도 변화에 따른 오차를 막고자 활액과 혈액내의 aspirin의 농도차를 이용하여 정확한 활액 성분농도를 측정하였다. 이상의 연구를 통하여 다음과 같은 결론을 얻었다. 1. 전체 환자의 생리식염수에 의한 악관절 활액의 희석계수는 1.4-12.9(5.5$\pm$4.2)로 상당히 넓은 범위를 나타내었다. 2. 만성 폐구성 과두걸림 환자군(n=7)의 생리식염수에 의한 활액의 희석계수 (6.2$\pm$3.5)는 퇴행성 관절질환을 갖는 환자군(4.4$\pm$5.7, n=4)과 유의한 차이가 없었다. 3. 만성폐구성 과두걸림군과 퇴행성 관절 질환군간의 활액성분의 농도는 유의한 차이가 없었으나 희석계수를 이용한 수정된 Hyaluronic acid와 총단백질의 농도는 만성 폐구성 과두걸림군의 경우에서 유의하게 더 높게 나타났다. 4. 악관절 도약술과 sodium hyaluronate의 주입 직후 만성 폐구성 과두걸림 환자군의 경우 평균 8.3mm의 추가적인 개구 증가로 유의한 차이가 관찰되었고 퇴행성 관절질환의 경우 평균 1.3mm의 추가적인 개구증가가 있었으나 유의한 차이가 관찰되지 못했다. 5. 시술전, 시술 1주후 및 4주후의 여러 검사항목을 비교한 결과 두 군에서 모두 시간의 경과에 따라 기능이상 및 동통 감소의 경향을 나타내었으나 유의하지는 않았으며 만성 폐구성 과두걸림의 경우 기능장애지수(dysfunction index) 와 최대개구시 동통의 정도는 시술전과 시술 4주후간에 유의한 차이가 관찰되었다.

• Journal of Ginseng Research
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• v.11 no.1
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• pp.66-76
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• 1987

When rice seeds were rinsed in If) Korean ginseng tea (KG 722, Korean Ginseng Product Co. Ltd. made) for 28 hours prior to seeding, the early growth was found relatively fast and their resistance against blight and harmful insects was increased. Rice yield showed that control group, rinsing group and spraying group were 514 kg/10a, 562 kg/ 10a and 571 kg/ 10a respectively. However, rinsing and spraying groups were 590 kg/ 10a (leaf spraying) and 605 kg/ 10a (spray immediate after seeding) respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.104-104
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• 2011

사중극 질량분석기(Quadrupole Mass Spectrometer, QMS)의 신뢰성을 향상시키기 위해 이온소스를 개선하고 평가하였다. 공정가스에 의한 오염 및 charging 효과로 인해 이온전류가 감소하는 현상을 발견하였고 이를 개선하기 위해 이온소스의 표면 거칠기를 줄여서 신뢰성을 향상시켰다. 또한 이온소스를 평가하는 방법으로 희석된 혼합가스를 이용하여 MDPP (Minimum Detectable Partial Pressure)를 측정하였고 이를 위해 희석된 가스의 이온 전류와 배경 노이즈의 비율(Signal/Noise)을 극대화시키면서 QMS를 튜닝하였다. 이 평가방법을 이용하여 상용 이온소스와 한국표준과학연구원에서 제작한 두 종류의 이온소스를 평가 비교하였다. QMS에 대한 국제표준안(ISO/TC 112 CD14291) 제정을 위한 진행상황도 소개하려고 한다.

• Journal of Hydrogen and New Energy
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• v.15 no.4
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• pp.348-354
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• 2004

Hydrogen gas has several merits such as lower ignition energy, wide flammability and shorter quenching distance. It leads to high thermal efficiency but backfire occurrence. In this study, feasibility of expansion of BFL(Back-Fire Limit) equivalence ratio and combustion characteristics by a dilution of hydrogen fuel are experimently examined by using experimental heavy duty single cylinder hydrogen fueled engine. As results, it is found that BFL equivalence ratio is expanded to rich range and torque is increased.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.557-566
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• 2009

This study was conducted to develop an organic control of powdery mildews of cucumber by using mayonnaise in green house. The treatment of 0.1~2% mayonnaise resulted in 8.3%~99.2% control efficiencies against powdery mildew of cucumber. 0.5% mayonnaise treatment resulted control values over 97% in disease. It did not adversely affected the photosynthesis of foliages. Although one application of mayonnaise to the foliage was not practically effective enough, two or three application of mayonnaise to the foliage at the 0.5% concentration resulted in excellent control against powdery mildews. This treatment could provide protection for 10~14 days after application. Among the type of mayonnaise, general mayonnaise revealed 97.5% control value, but mayonnaise containing low oil content revealed 39.3%~97.5% control values on powdery mildews at the 0.5% concentration. Therefore, oil content in mayonnaise played a essential material to control powdery mildew. Results indicated that mayonnaise could be used as organic control of powdery mildews of cucumber. This control might be environmentfriendly as well as cost-effective.