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봉선화(Impatiens balsamina L.)에 대한 pH 수준별 처리가 항산화 물질 및 관련 효소 활성에 미치는 영향
김학윤,Kim Hak Yoon 한국생명과학회 2005 생명과학회지 Vol.15 No.3
산성비가 식물 생장에 미치는 영향과 식물의 생화학적 방어반응을 조사하고자 봉선화를 이용하여 인공 산성비(pH 2.0, 3.0, 4.0, 5.6) 실험을 수행하였다. 산성비의 pH가 낮을수록 생육 피해는 심하게 나타났으며 pH 3.0 이하의 처리에 의해 잎에 암회색 또는 적갈색의 괴사반점이 생성되었다. MDA 함량은 pH 2.0 처리에서 약 $40\%$의 증가를 나타내었다. 산성비의 $H^+$ 부하량 증가에 따라 산화형인 DHA 및 GSSG의 함량이 증가하였다. 항산화효소인 SOD, APX, DHAR, GP등의 활성도 산성비의 $H^+$ 부하량의 증가에 따라 크게 증가하는 것으로 나타났다. 이상의 결과로 볼 때 산성비는 봉선화 식물에 활성산소 생성에 의한 산화스트레스를 일으키며, 이를 무독화하기 위해 식물의 생화학적 방어반응이 작용하는 것으로 사료된다 To investigate the effects of simulated acid rain (SAR) on growth and biochemical defense responses of plant, garden balsam (Impatiens balsamina L.) was subjected to four levels of SAR based on pH (5.6, 4.0, 3.0, 2.0) and placed in the growth chambers for 2 weeks. SAR drastically inhibited both height and dry weight of garden balsam. The content of total carotenoid was tended to decrease, but the level of malondialdehyde was significantly increased by SAR. As the pH levels decreased from 5.6 to 2.0, the content of dehydroascorbate and oxidized glutathione of the plant were significantly increased. The enzyme (superoxide dismutase, ascorbate peroxidase etc.) activities of the plant affected by SAR were increased as the pH decreased. The results indicate that garden balsam may receive oxidative stresses by the application of SAR and by which the plant growth can be significantly retarded. A biochemical protective mechanism might be activated to nullify the oxidative stresses generated through SAR.
피로 하중을 받는 열간 압연 연강판재의 기계적 성질과 모우드 변화에 관한 연구
김학윤,이성호 ( Hak Yoon Kim,Seong Ho Lee ) 한국열처리공학회 1995 熱處理工學會誌 Vol.8 No.4
Using natural frequency measurement method, which is one of NDT method, natural frequency of the hot-rolled mild steel plate(specimen) under fatigue loading was measured. Between the degradation of the specimen under fatigue loading and the variation of the natural frequency of the specimen was investigated. As a result, the degradation of the specimen was described and monitored as variation of natural frequency of specimen. The natural frequency of specimen decreased gradually under fatigue loading. This means the variation of material properties of specimen. Especially. It means the variation of Young`s modulus of specimen.
4종 촤화류에 대한 pH 수준별 처리가 잎의 완충능력, chlorophyll 함량 및 무기성분 용출에 미치는 영향
김학윤 한국생명과학회 2001 생명과학회지 Vol.11 No.3
This study was conducted to investigate the effect of simulated acid solution(SAS) on acid buffering capacity, chlorophyll content and butrient leacking in 4 herb species(Petunia hybrida Vilm, Gomphrena globosa L. Celosia cristat L. Salvia officinallis L) . The acid buffering capacity in the leves was increased in the treatment of pH 3.0 in Celosia L., whereas it was increased at pH 4.0 in Petunia Petunia hybrida Vilm. and Gomprean globosa L.. But, the acid buffering capacity of the leaves did not work at ph 2.0 treatment in 4 herb species. With decreasing pH level, the chlorophyll content of Petunia hybrida Vilm. and Gomphrena globosa L. Was markedly decreased than that of Gelosia cristata L. and Savia officinalis L. As the pH levels decreased from 5.6 to 2.0 the nutrient leaching from leaves was significantly increased in 4 herb species. In pH 4.0 and 5.6, the concentrations of nutrient leaching from leaves were higher in Perunia hybrida Vilm. and Gomphrean globosa L. than Gelosia cristata L. and Salvia officinalis L., Based on the results, there was a great differences in response to SAS among the 4 herb species. Im general, Gelosia cristata L. and Salvia officinalis L. represented a higher tolerance to SAS Petunia hybrida Vilm, and Gomphrena globosa L..
토양산성화가 봉선화(Impatiens balsamina L.) 및 만수국(Tagetes patula L.)의 생장에 미치는 영향
김학윤 한국생명과학회 2001 생명과학회지 Vol.11 No.2
To investigate the effects of soil acidification on growth of Impatiens balsamina L. plants were transplanted to acidified soils with H$_2$SO$_4$ solution. The concentrations of soluble Ca, Mg, K, Al and Mn in the acidified soils increased with increment of H$^{+}$ addition to the soil. In both species, the plant height and root length were inhibited by soil acidification, showing much severer inhibition in Impatiens balsamina L. than in Tagetes patula L., As the soil pH decreases, the growth of underground parts decreased greatly than that of above ground parts in both species. Total dry weight decreased with increased Al concentration as well as lowered soil pH in both plants. There was a strong positive correlation between relative total dry weight and molar (Ca+Mg+K) / Al ratio of the soil. The results suggest that molar(Ca+Mg+K)/ Al ratio of the soil may be useful indicator for assessing the critical load of acid deposition in herb species.s.
머리 움직임을 고려한 3차원 음 재생 방법에 관한 연구
김학윤 한국정보기술학회 2014 한국정보기술학회논문지 Vol. No.
As the 3D Sound reproduction algorithm is the technology that restores the lost spatial cue, which was lost given recording and playback, it obtains information same as the form in sound location, environment, and a sound source, which occurred by granting the spatial distribution information to auditory sense. Many conventional methods are proposed for implementing the 3D sound reproduction system. These methods have the problem which is not focused and considered on an effect of head movement. Hence, This paper develops and implements the adaptive 3D system with head movement sensor to improve previous ones. Performance of the proposed system is evaluated through listening tests. It shows the better results of the method for headphone than speaker and proves the better experimental results of the head movement than those of excluding the head movement. 3차원 음 재생 알고리즘은 녹음 및 재생 시에 잃어버린 공간 정보를 복원시키는 기술로, 청각의 공간 정보를 부여하여 발생된 음원의 위치나 환경과 같은 정보를 얻어 재생시키는 기술이다. 이와 같은 3차원 음 재생 시스템을 구현하기 위해 기존에 많은 기법들이 연구되어 왔다. 그러나 기존의 방법은 청취자의 머리 움직임에 따른 영향을 고려하고 있지 않다는 문제점을 갖고 있다. 따라서 본 연구에서는 청취자의 머리 움직임에 따른 영향을 고려하기 위하여 머리 이동 감지 센서를 부착하여 움직임에 적응할 수 있는 시스템을 구축하고, 청취 실험을 통하여 구현한 시스템의 성능 평가를 수행하였다. 그 결과, 방향의 인지에 있어서 스피커를 이용한 방법보다 헤드폰을 이용한 방법이, 머리움직임이 없는 경우보다 있는 경우가 더 좋은 결과를 얻었다.