• 제목/요약/키워드: Natural Experiment

검색결과 2,550건 처리시간 0.028초

Effect electric pulse application on the fruit body production of Tricholoma matsutake-In situ condition

  • Islam, Ferzana;Islam, Afsana;Ohga, Shoji
    • 농업과학연구
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    • 제40권1호
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    • pp.13-18
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    • 2013
  • Effect of electric pulse stimulation was tested on the fruit body formation of valuable mushroom Tricholoma matsutake in the field of natural habitat of this mushroom. After applying the electric stimulator to the specific area of pine forest we found that the treatment especially stimulated the fructification of T. matsutake. And the most valuable findings of our study was that only our treatment plots showed fruit body formation whereas the control plots and the whole natural habitats of our study area showed zero production of this mushroom during the same time. From the point of view of mushroom production, our experiment shows that fruit body production can be upgraded by using pulsed power as an electrical stimulation in the field of the natural habitat of this mushroom. These findings from our experiment confirm the effectiveness of the significance of pulsed power technology for the improvement of T. matsutake fruit body production in the natural habit of this mushroom.

천연아로마가 중학생의 자아개념에 미치는 효과 (The Study of the Effects of Natural Aroma Essential Oil on Self-concept in Middle School Students)

  • 김영선;차영숙;이금비;최용선;이한춘
    • 한국임상보건과학회지
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    • 제4권4호
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    • pp.730-736
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    • 2016
  • Purpose. The aim of this study was to provide Aromatherapist with analysis of the effect of natural aroma essential oil on middle school students' self-concept. Methods. In total, 20 students were recruited to answer a self-administered questionnaire in pre and post. The questionnaire was composed of questions about general self-concept, class self-concept, achievement self-concept, ability self-concept, social self-concept, family self-concept, emotional self-concept, physical self-concept. The natural aroma essential oil program was operational in a 90-minute once a week for ten weeks. Results. As a result, the score of emotional self-concept(t=-2.60, p<.05) is higher than pre the experiment post experiment. Conclusions. This study is to get a basic data of natural aroma should be applied to improve self-concept of middle school students.

녹차의 정유성분에 대한 특성 및 분석 (Characteristics and Analysis on the Refined Oil Component of Green-Tea)

  • 성기천
    • 한국응용과학기술학회지
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    • 제22권3호
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    • pp.241-249
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    • 2005
  • This experiment extracted the natural green-tea using ethanol and obtained the refined oil component after filterated green-tea extract. This study tested the antimicrobial effect as characteristics experiment, and analyzed refined oil component with pH-meter and GC/MS. In the result of this experiment, it obtained the next conclusions. In the first result of extraction experiment, it could know that extraction ratio of refined oil component appeared about 9.0%. In the second result of characteristics experiment, it could certificate that in case of increasing the refined oil component in concentration of 100ppm and above, and according to passage of cultivation time, the number of S-aureus and E-coli in microbe decreased less and less. But in case of blank test not adding the refined oil component, the number of microbe increased more and more. In these phenomena, it could certificate that refined oil component of green-tea appeared antimicrobial effect against microbe. In the third result of instrumental analysis, refined oil component of green-tea appeared about 7.6 in 1% distilled water solution with pH-meter, and the aromatic components of benzene, bonyl acetate, campene, ${\alpha},{\beta},{\gamma}$-pinnene etcs from refined oil component of green-tea was detected with GC/MS.

12-Hydroxyamoorastatone, a New Limonoid from Melia azedarach var. Japonica

  • Jong-Woong Ahn;Geon-Seek Yoo;Zaesung No;Seung-Ho Lee
    • Bulletin of the Korean Chemical Society
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    • 제14권5호
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    • pp.554-556
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    • 1993
  • A chemical investigation of the stem bark of Melia azedarach var. Japonica (Meliaceae) has led to a new limonoid, 12-hydroxyamoorastatone (1), whose structure has been elucidated by spectroscopic measurements including 2D-NMR. The 2D-NOESY experiment on its di-p-bromobenzoate derivative (1a) has established the relative configuration of 1.

Antioxidative and antimicrobial effects of crude extract prepared from Oriental medicinal plants in Korea

  • Seong, Nak-Sul;Kang, Myung-Hwa;Cha, Mun-Suk;Lee, Seung-Eun;Park, Don-Hee
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2001년도 추계학술발표대회
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    • pp.489-492
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    • 2001
  • There were many reports on the natural antioxidants, but only tocopherol has been widely used despite of its high market price because of its recognized safety. On the other hands, antimicrobial effects of various plant extracts also have been extensively studied. There exist many substances showing antimicrobial activity in plants and their activities have been studied.

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디젤엔진개량에 의한 천연가스차량전환에 관한 연구 (A Study on Natural Gas Vehicle Conversion by Diesel Engine Improvement)

  • 한영출;오용석;나완용
    • 한국생산제조학회지
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    • 제8권2호
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    • pp.94-94
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    • 1999
  • Natural gas is considered to be on e of the most promising candidates for a clean substitute fuel and a great amount of research on the compressed natural gas(CNG) fueled vehicle has been performed. In this s tudy, we try to understand the property of CNG fuel with using CNG engine experiment. In order to present the direction and application of CNG, we experiment with various operating conditions that is, spark timing, A/F ratio, air quantity and fuel quantity, etc. 11,967 cc engine was used in the experiment and the engine fuel ratio was determined in the way that the performance of dedicated CNG engine is corresponded to that of existing diesel engine. The performance and dedicated CNG engine were measured by changing the fuel injection timing. The dedicated CNG engine was proved to be good in describing the experimental results and according to the actual road test, acceleration and constant speed driving for dedicated CNG engine was better than existing diesel engine.

천연항균성 물질을 이용한 Vibrio vulnificus 의 살균 및 독소생성 억제효과 (disinfectant and Inhibitory Effect of Natural Antimicrobial Agent on Vibrio vulnificus in Fish)

  • 조성환;서일원;최종덕;전상수;라택균;정수근;강동훈
    • 한국식품위생안전성학회지
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    • 제7권2호
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    • pp.99-106
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    • 1992
  • To prevent food-poisoning outbreaks by Vibrio vulnificus the antimicrobial efficacy of grapefruit seed extract (GFSE) was examined. Minimal inhibitory concentration (in vitro) for the microorganism was found to be 50∼100 ppm. Transmission electron micrographs of Vibrio vulnificus showed the biocidal action of this natural antimicrobial agent would be related to specific respiratory effect coupled with the destruction of permeable function of microbial cell membrane. After Anguilla japonica GFSE-injected to the body was incubated in the seawater contaminated by Vibrio vulnifiucs the fish meats were taken up, mixed with control diet and used as a diet in the feeding experiment. In this experiment the effect of GFSE treated with fish muscle on body weight, protein efficiency ratio, serum enzymes and serum blood components of broiler chicks was investigated. It is proved from this study that there is neither Vibriosis nor toxicity associated with GFSE itself an fish meats treated with it when it is injected to the fish body at a level of 250 ppm or less.

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사립학교가 공립학교에 비해 보다 효율적인가?: 한국의 자연실험 경험 (Are Private Schools More Effective than Public Schools?: Experience form a Natural Experiment in Korea)

  • 남기곤;성기선
    • 노동경제논집
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    • 제32권3호
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    • pp.91-121
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    • 2009
  • 이 논문에서는 한국의 경우 개별 학군 내에서 사립학교와 공립학교 간에 학생 배분이 무작위로 이루어진다는 특수성을 이용하여, 사립학교가 공립학교에 비해 학생들의 성적향상 측면에서보다 효율적인지를 분석하기 위한 자연실험 분석을 실시하였다. 학군의 고정효과를 통제한 모델을 분석한 결과, 사립학교가 공립학교에 비해 학생들의 성적이 보다 향상된다는 통계적으로 유의미한 결과를 확인할 수 없었다. 단 상위 성적 계층의 여학생들의 경우, 사립학교 학생이 0.13 표준편차만큼 성적이 더 향상되는 것으로 나타났다.

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