• 제목/요약/키워드: $^1H-\

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NGC 7790의 UBVI CCD 측광 (UBVI CCD Photometry of NGC 7790)

  • 최동열;김희수;임범두;성환경
    • 한국지구과학회지
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    • 제36권7호
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    • pp.661-673
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    • 2015
  • 우즈베키스탄 Maidanak 천문대 AZT-22 1.5 m 망원경(f/7.74)과 SITe $2000{\times}800$CCD를 사용하여 3개의 ${\delta}$ Cep 변광성 CEa Cas, CEb Cas 및 CF Cas가 있는 중년 산개성단 NGC 7790의 UBVI 측광 관측을 수행하였다. 관측자료는 IRAF/DAOPHOT를 이용하여 PSF 측광을 수행하였으며, V와 I 필터에서 모두 측광된 별의 수는 총 1008개이며, 측광의 한계등급은 $V{\approx}22$등급이다. 대기소광계수 및 측광영점을 결정하기 위하여 천구적도에 있는 여러 표준별과 청색 및 적색 표준별을 다양한 대기투과량에서 관측하였다. 표준별 측광을 통해 대기소광계수 및 측광영점을 결정하고, 성단의 측광자료는 Johnson-Cousins UBVI 표준계로 변환하였다. NGC 7790의 UBVI 색-등급도와 색-색도에서 이 성단의 B와 V 필터에서의 색초과량 [$E(B-V)=0.58{\pm}0.02$], B와 V 필터에서의 선택적 소광량 [$R_V{{\equiv}}A_V/E(B-V)=3.02{\pm}0.09$] 및 거리지수($V_0-M_V=12.65{\pm}0.10$)를 얻었다. H-R도에서 세페이드 변광성의 위치를 고려하여 나이를 결정하였다. 이 과정에서 Padova 연구집단(Bressan et al., 2012)의 등연령곡선(Z=0.019)과 Geneva 연구집단($Ekstr{\ddot{o}}m$ et al., 2012)의 등연령곡선(Z=0.014)을 모두 사용하였고, 그중에서 자전을 고려한 Geneva 연구집단의 진화모형이 관측자료와 잘 일치하여 NGC 7790의 나이로 log $age=8.05{\pm}0.05$ [yr]를 얻었다. 또 NGC 7790내 세페이드 변광성의 절대등급은 세페이드 변광성의 평균 주기-광도 관계에 비해 분산 범위 내에 있기는 하지만 주어진 주기에서 평균적으로 약 0.5등급 정도 밝음을 확인하였다.

종 분포 모형을 이용한 구상나무림의 지속 및 쇠퇴에 관한 연구 - 전라남도 광양시 백운산을 중심으로 - (A Study for Continue and Decline of Abies koreana Forest using Species Distribution Model - Focused in Mt. Baekwun Gwangyang-si, Jeollanam-do -)

  • 조선희;박종영;박정호;이양근;문이만;강상호;김광현;윤종국
    • 한국산림과학회지
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    • 제104권3호
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    • pp.360-367
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    • 2015
  • 본 연구에서는 백운산 내 구상나무 서식지를 조사하여 현존 분포도를 작성하고 분포에 영향을 미치는 생물학적 환경인자와 비 생물학적 환경인자의 기여도를 정량화하여 서식지 또는 대체서식지로써 잠재성을 가지고 있는 지역을 도출하고 보호구역 설정 안을 제시하였으며, RCP 8.5 기후변화 시나리오를 적용하여 기후변화가 향후 구상나무의 분포에 미치는 영향을 분석한 미래 잠재 서식지를 예측 하였다. 연구 결과 백운산 내 구상나무는 3,325개체 (DBH >= 2.5 cm)가 서식하고 있었고 분포 면적은 150 ha 정도였다. 해발 900 m에서 구상나무의 개체가 확인되어 1,200 m까지 분포하고 있었으며, 잠재 분포도를 기반으로 현재 구상나무가 서식하기에 적합한 지역은 상봉, 억불봉, 따리봉, 도솔봉을 중심으로 현존 분포 면적의 3배인 450 ha로 분석되었다. 주봉인 상봉 인근이 구상나무의 서식에 가장 적합한 잠재력을 가진 임분으로 평가 되었으며, 남사면보다는 북사면을 선호하는 경향을 보이고 있었다. 기후변화 시나리오 RCP 8.5를 적용하여 미래의 잠재적 분포를 분석한 결과 2050년에는 상봉 주변을 중심으로 20 ha까지 서식지 면적이 감소될 것으로 나타나며, 2080년에는 서식에 적합한 지역이 존재하지 않을 것으로 예측된다. 이러한 결과로 볼 때 지구온난화가 가속화될수록 구상나무는 저지대에서 고지대로 서식지의 이동 양상이 뚜렷해질 것으로 판단된다.

마른 가오리의 풍미성분(風味成分) (Flavor Components in Sun-Dried Ray)

  • 차용준;안창범;이태헌;정영훈;이응호;김세권
    • 한국식품영양과학회지
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    • 제14권4호
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    • pp.370-374
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    • 1985
  • 독특한 맛과 냄새성분 때문에 남도지방의 특산물로서 우리나라에서 즐겨 이용되고 있는 마른가오리의 풍미성분을 밝힐 목적으로 유리아미노산, 핵산관련물질, 총크레아티닌 및 베타인등의 정미성분과 지방산 그리고 냄새성분을 분석하였다. 마른가오리의 VBN 및 아미노질소는 각각 60.98mg% 및 95.82mg%였으며, 카르보닐값은 97.67meq/kg였고 pH는 7.18이었다. 유리아미노산함량은 1773.3mg%이었고 이중 taurine, lysine, leucine, alanine, glycine, glutamic acid, proline 및 valine 등이 전체의 80%정도를 차지하였다. 핵산관련물질중에서는 hypoxanthine의 함량이 가장 많았다. 전엑스분질소 함량은 1965.6mg% 이었으며 이중 암모니아질소가 519.0mg%로써 가장 많았고 다음으로 유리 아미노산질소, 총크레아티닌질소 및 핵산관련물질소 순이었다. 총지질에 대한 구성비는 중성지질이 92.5%, 인지질이 5.5%였으며 총지질과 중성지질에서는 폴리엔산이 각각 42.0%, 45.3%로써 가장 많은 량을 차지하였고 인지질에서는 포화산과 폴리엔산이 39% 정도로서 비슷한 양이었다. 총지질, 중성지질 및 인지질에서 양적으로 많은 지방산은 $C_{16:0},\;C_{22:6},\;C_{18:1},\;C_{18:0},\;C_{20:4}$ 순이었다. 또한 냄새성분중 휘발성지방산은 8종이 동정되었는데 이중 고린내 특유의 냄새성분을 나타내는 isocaproic acid, caproic acid, isobutyric acid 및 butyric acid 등이 많은 비율적 차지하였고 휘발성카르보닐화합물에서도 8종이 동정되어 이중 2-butanone, pentanal 및 2-methylpropanal등이 많은 비율을 차지하였다.

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패 추출물의 항산화능 및 이화학적 특성에 미치는 감마선 조사의 영향 (Effects of γ-Irradiation on Antioxidant and Physicochemical Properties of Ishige okamurai Extracts)

  • 김미정;송유진;이소영;김꽃봉우리;김서진;이소정;윤소영;김아람;전유진;박진규;최종일;이주운;변명우;안동현
    • 한국식품영양과학회지
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    • 제37권11호
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    • pp.1485-1490
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    • 2008
  • 감마선 조사는 식품의 부패방지 및 안정성 향상을 위해 그 사용 범위가 확대되고 있다. 이에 본 연구에서는 패 분말과 70% 발효주정 추출물에 3, 7 및 20 kGy로 감마선을 조사하여 항산화능의 변화를 알아보았다. 패 분말에 감마선 조사하여 70% 발효주정으로 추출한 뒤 수율, 총 페놀화합물 함량 및 DPPH 라디칼 소거능의 변화를 알아본 결과, 조사선량이 증가함에 따라 수율은 증가하여 20 kGy 조사구에서는 19%의 수율을 보였으나, 총 페놀화합물 함량 및 DPPH 라디칼 소거능에 있어서는 유의적인 차이를 보이지 않았다. 패 70% 발효주정 추출물에 감마선 조사하여 총 페놀화합물 함량, 항산화능 및 이화학적 특성 변화를 알아본 결과, Rancimat에 의한 항산화도에 있어서는 비조사구 및 3, 7, 20 kGy 조사구 각각 1.07, 0.74, 0.91 및 1.22의 AI값을 보여 3과 7 kGy 조사구는 감소하였으며, 20 kGy 조사구는 증가하였다. 총 페놀화합물 함량과 DPPH 라디칼 소거능은 분말에 감마선 조사하였을 때와 같이 유의적인 차이를 보이지 않았다. 색도는 감마선 조사선량이 증가함에 따라 유의적으로 색이 감소하는 경향을 보였고, pH의 경우 조사구가 비조사구보다 다소 감소한 값을 보였다. 따라서 감마선 조사된 패 70% 발효주정 추출물은 본래의 항산화 활성을 유지하면서 비조사구보다 패 추출물 본래의 색이 옅어져 식품에 첨가시 식품자체의 색에 큰 영향을 미치지 않아 식품 천연 항산화제로서 적용이 용이할 것으로 사료된다.

Evaluation of Metal-Amino Acid Chelates and Complexes at Various Levels of Copper and Zinc in Weanling Pigs and Broiler Chicks

  • Lee, S.H.;Choi, S.C.;Chae, B.J.;Lee, J.K.;Acda, S.P.
    • Asian-Australasian Journal of Animal Sciences
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    • 제14권12호
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    • pp.1734-1740
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    • 2001
  • Feeding trials using weanling pigs and broiler chicks were conducted to evaluate the efficacy of different metal-amino acid chelates and complexes at various levels of copper and zinc on the performance and fecal excretions. A total of 200 weanling pigs (Large White ${\times}$ Yorkshire ${\times}$ Duroc, $11.20{\pm}0.81kg$) were randomly assigned to 5 dietary treatments following a randomized complete block design. Each treatment was replicated 4 times with 10 pigs per pen. The dietary treatments were designated as : A-diet containing 170 ppm Cu from $CuSO_4$ and 120 ppm Zn from $ZnSO_4$, B-diet containing 85 ppm Cu from Cu-amino acid chelate (CAC) and 60 ppm Zn from Zn-amino acid chelate (ZAC), C-diet containing 170 ppm Cu from CAC and 120 ppm Zn from ZAC, D-diet containing 85 ppm Cu from Cu-lysine complex (CL) and 60 ppm Zn from Zn-methionine complex (ZM), and E-diet containing 170 ppm Cu from CL and 120 ppm Zn from ZM. On the other trial, 144 of one day old broiler chicks were randomly distributed to 6 dietary treatments following a completely randomized design. Each treatment was replicated 3 times with 8 chicks per replicate. The dietary treatments were as follows: 1-diet with 60 ppm Cu from $CuSO_4$ and 40 ppm Zn from $ZnSO_4$, 2-diet with 120 ppm Cu from $CuSO_4$ and 80 ppm Zn from $ZnSO_4$, 3-diet with 60 ppm Cu from CAC and 40 ppm Zn from ZAC, 4-diet with 120 ppm Cu from CAC and 80 ppm Zn from ZAC, 5-diet with 60 ppm Cu from CL and 40 ppm Zn from ZM, and 6-diet with 120 ppm Cu from CL and 80 ppm Zn from ZM. In Exp. 1 with pigs, there was no difference on average daily gain and average daily feed intake observed among treatments. There was improvement (p<0.05) on the overall feed conversion ratio (FCR) of pigs fed diet containing 120 ppm Zn and 170 ppm Cu from metal-amino acid chelates relative to those fed diet containing inorganic sources of Cu and Zn but equally efficient as those fed diet containing metal-amino acid complexes. Pigs fed diet containing either metal-amino acid chelates or complexes as sources of Cu and Zn had higher (p<0.05) Cu and Zn concentration in serum and lower (p<0.05) in feces than those receiving diet with inorganic sources. In Exp. 2 with broiler chicks, the overall FCR was not different among treatments. Higher (p<0.05) Cu and Zn concentration in serum was obtained from birds fed diet with 60 ppm Cu and 40 ppm Zn from metal-amino acid chelates compared to those fed diet with inorganic sources of Cu and Zn. Also, the feces collected from birds fed diet with either metal-amino acid chelates or complexes contained generally lower Cu and Zn than those birds fed diet with inorganic sources. The higher the dietary level of Cu and Zn the higher the Cu and Zn concentration in the feces. Based on the results, both metal-amino acid chelates and complexes of Cu and Zn at low levels (Zn 60 ppm, Cu 85 ppm for weanling pigs and Zn 40 ppm, Cu 60 ppm for broiler chicks) are not different from that of high levels of inorganic sources in maintaining growth performance and serum concentration. The fecal excretions for Cu and Zn were greatly reduced when organic sources were used.

노인의 건강증진을 위한 율동적 운동프로그램의 적용효과 (An Application Effect of Rhythmic Movement Program for the Health Promotion in the Elderly)

  • 이숙자
    • 대한간호학회지
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    • 제30권3호
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    • pp.776-790
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    • 2000
  • Every year the number of the elderly increases in Korea thanks to the improvemen of social and economical levels and the development of medicine. However, many problems such as insufficent care and the isolation of the elderly have been commonplace. This trend exists not only because of increased lifespan but also the changing social structure of the nuclear family. Accordingly, inspite of the development of medicine, geriatric diseases including circulatory diseases are increasing in proportion of elderly population, as well as the severity. Therefore, it is important to emphasize that health care programs provide the best possible health care and functional capacities in terms of healthy elderly lifestyles. Especially, the phenomena of aging and geriatric diseases taking place with the elderly naturally are affected by lifestyle and the drastic changes in exercise patterns. This study aims to improve geriatric health by introducing a rhythmic movement program for the elderly to estabilish a health-promoting self-care system and by developing quality of life, perceived health status, their physical and physiological functions and emotional state. The theoretical framework used in this dissertation is derived from the Health-Promoting Self-Care System Model (Simmons, 1990), which integrates the Self-Care Deficit Nursing Theory (Orem, 1985), the interaction model of Client Health Behavior (Cox, 1982) and the Health Promotion Model (Pender, 1987). As a quasi-experimental design, the nonequivalent control group pretest-posttest design is utilized for this study. The subjects of this study consist of 64 people, over 65 years old who live in 2 nursing homes for the aged located in S city , Kyong-gi province and volunteered for this study from July, 12, 1999 to September, 17, 1999. They are divided into two groups:33 in the experimental group and 31 in the control group. The experimental group particpated in the Rhythmic Movement Program at the nursing home, which was comprised of 45 minutes a session, 5 sessions a week during 9 weeks. In order to measure the results of the Rhythmic Movement Program, aspects of perceived health status, balance, flexibility, grip strength, leg strength, heart rate, blood pressure, depression, anxiety and the quality of life were measured before and after participating in the Rhythimic Movement Program for the experimental group after 9 weeks, as well as the control group. The collected data were processed by SPSS PC+ and analyzed by the X2 test, t-test, ANCOVA and the Pearson Correlation Coefficient. The results of this study are as follows: 1. The perceived health status conditions in the experimental group show statistically significant improvement when compared to the control group (F=17.51, p=.000). 2. The physical and physiological functions, that is, balance (F=17.51, p=.000), flexibility (F=8.01, p=.006), grip strength (F=3.21, p=.018) and leg strength (F=25.78, p=.000) in the experimental group are higher than the control group. The vital signs, that is, the number of heart rate (F=.022, p=.884), systolic pressure (F=1.73 p=.193), and diastolic pressure (F=2.74, p=.103) in the experimental group compared to the control group decreased, but doesn't show statistically significant differences. Immune responses (F=5.13, p=.003) showed statistically significant increases in the experimental group when compared to the control group. 3. The emotional state are improved, that is, degree of depression (F=11.56, p=.001) and degree of anxiety (F=9.14, p=.004) in the experimental group showed statistically significant decreases. 4. The quality of life in the experimental group (F=3.03, p=.037) showed statistically significant differences compared to the control group. 5. The observations of the relationships among the perceived health status, emotional state , the quality of life, the relationships between the perceived health status, the degree of depression (r=-.653, p=.000) and the degree of anxiety (r=-.786, p=.000) were in contrary propotions, while the relationships between the perceived health status and the quality of life (r=.234, p=.008) were in direct propotion. In conclusion, the Rhythmic Movement Program used in this study for geriatric nursing care is simple and safe for application to the elderly and shows significant effects by implementing 5 sessions a week for 9 weeks. The Rhythmic Movement Program improves the quality of life, maintains as well as improves the physical and physiological fuctions and emotional state, therefore this program is strongly recommended for positive applications for independant geriatric nursing health care.

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급성(急性) 기아(饑餓)마우스의 간단백질(肝蛋白質), 핵산(核酸) 및 Guanine Deaminase 활성(活性)에 관(關)한 연구(硏究) (A Study on The Content of Liver Protein, Nucleic Acids, and Guanine Deaminase Activity of Mouse During Acute Starvation)

  • 박승희;김승원
    • Journal of Nutrition and Health
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    • 제1권2호
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    • pp.107-115
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    • 1968
  • Number of aspects, not only nutritional but social as well as political involved in human starvation pose nowadays global problems. In order to help establish the minimum nutritional requirements in the daily life of a man and to free people as well from either undernourishment, malnutrition or even starvation many workers have devoted themselves so far on the research programs to know what and how number of metabolic events take place in animals in vivo. It is the purpose of the present paper to examine in effect to what extent both of the protein and nucleic acids (DNA & RNA) together with an enzyme, guanine deaminase, which converts guanine into xanthine and in turn ends up to uric acid as an end product, undergo changes, quantitatively during acute starvation, using the mouse as an experimental animal. The mouse was strictly inhibited from taking foods except drinking water ad libitum and was sacriflced 24, 48, and 72 hours following starvation thus acutely induced. The animals consisted of two experimental groups, one control and another starvation groups, each being consisted of 6-24 mice of whose body weights ranged in the vicinity of 10 g. The animals were sacriflced by a blow on the head, followed by immediate excision of their livers into ice-cold distilled water, washing adherent blood and other contaminant tissues. The liver was minced foramin, by an all-glass homogenizer immersing it in an ice-bath, followed by subsequent fractionatin of the homogenate (10% W/V in 0.25M sucrose solution made up with 0.05M phosphate buffer of pH 7.4). For the liver protein and guanine deaminase assay, the 10% homogenate was centrifuged at 600 x g for 10 minutes to eliminate the nuclear fraction; and for the estimation of DNA and RNA, the homogenate was prepared by the addition of 10% trichloroacetic acid in order to free the homogenate from the acid-soluble fraction, the remaining residue being delipidate by the addition of alcohol and dried in vacuo for later KOH (IN) hydrolysis. The changes in body and liver wegihts during acute starvation were checked gravimetrically. Protein contents in the liver were monitored by the method of Lowry et al; and guanine deaminase activities were followed by the assay of liberated ammonia from the substrate utilizing the Caraway's colorimetry. The extraction of both DNA and RNA was performed by the Schmidt-Thannhauser's method, which was followed by Marmur's method of purification for DNA and by Chargaff's method of purification for RNA. The determinations of both DNA and RNA were carried out by the diphenylamine reaction for the former and by the orcinol reaction for the latter. The following resume was the results of the present work. 1. It was observed that the body as well as liver weights fall abruptly during starvation, and that the loss of body weight showed no statistical correlation with the decreases in the content of liver protein. 2. The content of liver protein and activity of liver guanine deaminase activity as well decline dramatically, and the specific activities of the enzyme (activity/protein), however, decreased gradually as starvation proceeded. 3. Both of the nucleic acids, DNA and RNA, showed decrements in the liver of mouse during acute starvation; the latter, however, being more striking in the decline as compared to the former. 4. The decreases in the liver protein content as resulted from the acute starvation had no statistically significant correlation with the decrements of DNA in the same tissue, but had regressed with a significant statistical correlation with the fall of RNA in the tissue. 5. The decrease in the activity of guanine deaminase in the liver of mouse during acute starvation was functionally more proportional to the decrease in RNA than DNA, and moreover correlated with the changes in the content of the liver protein. 6. The possible mechanisms involved during in this acute starvation as bring the decreases in the contents of DNA, protein, and guanine deaminase were discussed briefly.

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조류 성장 억제를 위한 녹조 및 적조 발생과 황사의 상관관계 초기적 연구 (An Initiative Study on Relationship between Algal Blooms and Asian Dust for Regulation of Algal Blooms)

  • 김태진;정재칠;서라벌;김형모;김대근;전영신;박순웅;이세윤;박준조;이진하;이재정;이은주
    • KSBB Journal
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    • 제29권4호
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    • pp.285-296
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    • 2014
  • Although the problems of the algal blooms have been world-widely observed in freshwater, estuary, and marine throughout the year, it is not yet certain what are the basic causes of such blooms. Consequently, it is very difficult to predict when and where algal blooms occur. The constituents of the Asian dust are in a good agreement with the elements required for the algal growth, which suggests some possible relationship between the algal blooms and the Asian dust. There have been frequently algal blooms in drinking water from rivers or lakes. However, there is no any algal blooms in upwelling waters where the Asian dust cannot penetrate into the soil due to its relatively weak settling velocity (size of particles, $4.5{\pm}1.5{\mu}m$), which implies the possible close relationship of the Asian dust with algal blooms. The present initiative study is thus intended firstly in Korea to illustrate such a relationship by reviewing typical previous studies along with 12 years of weekly iron profiles (2001~2012) and two slant culture experiments with the dissolved Asian dust. The result showed bacterial suspected colonies in the slant culture experiment that are qualitatively in a good agreement with the recent Japanese studies. Since the diatoms require cheap energy (8%) compared to other phytoplankton (100%) to synthesize their cell walls by silicate, the present results can be used to predict algal blooms by diatoms if the concentrations of iron and silicate are available during spring and fall. It can be postulated that the algal blooms occur only if the environmental factors such as light, nutrients, calm water surface layer, temperature, and pH are simultaneously satisfied with the requirements of the micronutrients of mineral ions supplied by the Asian dust as enzymatic cofactors for the rapid bio-synthesis of the macromolecules during algal blooms. Simple eco-friendly methods to regulate the algal blooms are suggested for the initial stage of blooming with limited area: 1) to cover up the water surface with black curtain and inhibit photosynthesis during the day time, 2) to blow air (20.9%) or pure oxygen into the bottom of the water and inhibit rubisco for carbon uptake and nitrate reductase for nitrogen uptake activities in algal growth during the night, 3) to eliminate the resting spores or cysts by suction of bottom sediments as deep as 5 cm to prevent the next year germinations.

캐모마일(Martricaria chamomilla L.)의 생리활성 (Biological Activity of Chamomile (Matricaria chamomilla L.) Extracts)

  • 조영제;윤소정;김정환;천성숙
    • 한국식품영양과학회지
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    • 제34권4호
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    • pp.446-450
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    • 2005
  • 캐모마일(Matricaria chamomilla L.)을 성인병 예방을 위한 기능성 식품소재로 이용하기 위하여 추출물의 생리활성 효과를 조사하였다. 추출물의 phenol 함량은 열수추출물이 $23.64{\pm}0.35\;mg/g$이었으며, $60\%$ 알콜추출물은 $24.98{\pm}0.20\;mg/g$으로 $60\%$ 알콜추출물의 phenol 함량이 다소 높게 나타났다. 캐모마일의 HPLC 분석 결과 생리활성 효과가 높은 rosemarinic acid, quercetin의 함량이 많은 것으로 보아 생리활성 효과가 있을 것으로 사료된다. 각 추출물의 항산화 효과는 DPPH가 열수추출물과 $60\%$ 알콜추출물이 각각 $91.05\%$$95.49\%$로 높게 나타났고, antioxidant protection factor (PF)는 열수추출물이 $0.71\pm0.02$로 지용성 물질에 대한 항산 화력은 낮았으나, $50\%$ 알콜추출물은 $1.48\pm0.03$으로 높은 PF를 나타내어 열수추출물보다는 $60\%$ 알콜추출물이 지용성에 대한 항산화력이 더 높다는 것을 알 수 있었다. Helicobater pylori에 대한 추출물의 항균활성은 열추추출물의 경우 clear zone이 나타나지 않았으며, $60\%$ 알콜추출물의 경우 $200{\mu}g/mL$ mL의 농도일 때 9.42 mm의 clear zone이 관찰되어 $60\%$ 알콜추출물에서만 낮은 저해활성이 있는 것으로 판단되었다. ACE 저해효과는 열수추출물이 $87.98\%,\;60\%$ 알콜추출물이 $91.36\%$의 저해효과를 나타내어 높은 고혈압 효과를 나타내었다. XOase에 대한 억제효과는 열수추출물이 $73.48\%,\;60\%$ 알콜추출물이 $81.96\%$의 저해효과를 나타내어 XOase에 대한 높은 저해를 관찰할 수 있었다. 이러한 결과로 캐모마일의 $60\%$ 알콜추출물이 항산화제, 고혈압 및 항관절염 소재로의 개발이 기대되어었다.

고체산화물 연료전지용 La0.7Sr0.3Ga0.6Fe0.4O3-δ계의 메탄부분산화반응 (Partial Oxidation of CH4 Using {0.7}Sr0.3Ga0.6Fe0.4O3-δ for Soild Oxide Fuel Cell)

  • 이승영;이기성;이시우;김종원;우상국
    • 전기화학회지
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    • 제6권1호
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    • pp.59-64
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    • 2003
  • 고상 반응법을 이용하여 $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$ 분말을 합성하고 소결하여 혼합전도성 분리막을 제조하였다. 제조된 분리막들은 페롭스카이트 단일상 결정구조를 나타내었으며, $95\%$, 이상의 상대밀도를 나타내었다. 산소이온 변환 능력을 향상시키기 위해 $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$의 양 표면에 $La_{0.6}Sr_{0.4}CoO_{3-\delta}$ paste를 스크린 프린팅 방법으로 코팅한 결과, 코팅되지 않은 분리막에 비해 산소투과 유속이 크게 증가하여 $950^{\circ}C,\; {\Delta}P_{o_2}=0.21 atm$에서 약 $0.5ml/min{\cdot}cm^2$의 값을 나타내었다. 이러한 산소투과 유속은 표면 코팅층이 다공성일수록, $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-\delta}$의 결정립 크기가 증가할수록 증가하는 경향을 나타내었다. 제조된 디스크 형상의 소결체를 이용하여 $950^{\circ}C$에서 메탄부분산화반응을 행한 결과 $40\%$ 이상의 메탄전환율과 합성가스의 수율을 얻을 수 있었으며, CO의 선택도는 $100\%$를 나타내었다 또한, $950^{\circ}C$의 메탄분위기에서 600시간의 장기부분산화반응을 통해 상의 안정성을 확인하였다.