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        검색결과 605

        141.
        1994.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 reed canarygrass silage의 품질을 향상시키고 호기적 변패를 방지시킬 목적으로 재료를 약 1.5cm 길이로 절단하여 formic acid, caproic acid 및 두가지 산을 혼합하여 첨가한 silage를 9개의 처리구로 나누어 실험용 silo에 제조하였으며, silage의 품질분석을 위해서 두께 0.1mm, 용량 50kg의 vinyl bag을 이용하였다. 또한 호기적 상태에서의 온도변화, 질소 함량 변화 및 변패방지를 위
        4,000원
        144.
        1993.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A Stepped beam with immovable ends under forced vibrations with large amplitude is investigated by using the finite element method and the Ritz vectors. Unlike the Eigen vectors, the Ritz vectors are generated by a simple recurrence relation. Moreover the Ritz vectors yield much faster convergence with respect to the number of vectors used than the use of Eigen vectors. The computer program is developed for nonlinear analysis using Ritz vectors instead of Eigen vectors and numerical examples are analysed for deflections and natural frequencies of stepped beam under various support conditions. Results show that the proposed method is valid and efficient.
        4,000원
        145.
        1992.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼멸구 수컷 정소에서 염색체의 변이정도를 생태형 별로 관찰하였다. 세포 분열 지수는 생태형 3에서 가장 높았고 그 다음으로 생태형 1, 생태형 2이었다. Agmatoploidy, aneuploidy, 성염색체의 loose pairings과 같은 염색체의 구조적 변화는 생태형 1, 생태형 2, 생태형 3순으로 높았다. 감수분열 제1분열기 중기는 성염색체가 상염색체로부터 현격하게 분리되어 있는 세포의 수는 생태형 2에서 가장 높았다.
        4,000원
        146.
        1992.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        초 록 한국, 중국, 필리핀산 흰등멸구의 계량형태학적 차이를 분석하기를 위하여 총 89개 부분의 형태적 특징(촉각 34, 다리45, 주둥이10)을 조사하고 계량형태적 분석을 위하여 정준 판별분석법을 이용하였다. Scatter plot diagram 상에서 3개 집단의 중심점은 분리현상이 뚜렷하였고 그 정도는 단시형 암컷에서 크게 나타났다. Mahalanobis distance(MD)는 단시형 암컷의 경우 3개 집단 모두 5%에서 유의성이 있었고, 장시형 암컷의 경우 MD는 중국산 대 필리핀산, 한국산 대 필리핀산이 각각 0.1%, 1%에서 유의성이 있었으나, 중국산 대 한국산은 유의성이 없었다.
        4,000원
        147.
        1991.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was conducted to investigate the effects of propionic acid and wilting on fermentation quality of Italian ryegrass silage. Grass material was wilted for a day before ensiling and propionic acid(0. 0, 0. 2. 0. 5 and 0.8 7~ of fresh matter)
        4,000원
        148.
        1990.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자유 및 강제진동하중이 작용하는 양단지지된 변단면 들보의 우한 진폭 운동을, 축방향 및 전단변형과 회전관성을 고려한 유한요소를 이용하여 추적하였다. 수정된 조화하중 행렬을 도입하여 조화하중이 작용하는 변단면 들보와 비조화하중이 작용하는 들보의 유한진폭의 운동을 비선형해석을 하였다. 여러가지 경계조건에 대한 고유진동수와 변위를 계산한 예들은 제안된 방법이 효과적이며 유효함을 보여준다.
        4,000원
        151.
        1986.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The characteristics of tidal exchange in Masan Bay were studied on the basis of salinity observations and current measurements in the summer of 1985. The exchange ratio of the sea water was calculated using three different formulas. The tidal exchange rate was estimated to be smaller than that of another bays in the southern coast of Korea. The tidal exchange ratios in Masan Bay at spring tide were deduced to be 2.4-11.7%. While those at neap tide were 2.0-9.1%. Though tidal range of neap tide is smaller than that of spring tide. the tidal exchange ratio in the bay can be increased in case of highly stratified vertical structure.
        4,000원
        153.
        2019.02 KCI 등재 서비스 종료(열람 제한)
        본 연구는 우리나라에 자생하고 있는 팥배나무 11개 집단으로부터 잎의 형태적 특성과 변이를 조사하여 조경수로서의 팥배나무 선발 및 육종에 대한 기초자료를 제공하고자 수행하였다. 잎의 형태적 특성 12개를 조사하고 집단 간 차이를 비교한 결과 11개 특성에서 유의적인 차이가 인정되었다. 특히 잎의 길이와 너비, 엽면적 등 잎 크기와 관련된 인자들은 마니산 집단이 모두 상위그룹에 속하여 비교적 큰 경향을 나타냈으나, 백운산과 두륜산은 하위 그룹으로 분류되어 비교적 작은 경향을 나타냈다. 주성분 분석을 실시한 결과 제1 주성분은 29.9%의 설명력이 있으며 엽면적, 잎의 너비, 잎의 길이 순으로 높은 상관을 나타내어 잎의 형태적 차이를 설명하는 주요 요인으로 나타났고, 제5 주성분까지 72.9%의 누적 설명력을 나타냈다. 제5 주성분까지의 득점치를 새로운 변량으로 하여 유집분석을 실시한 결과 Ⅰ그룹인 광교산과 안면도 집단, Ⅱ그룹인 덕유산 등 3집단, Ⅲ그룹인 발왕산 등 3집단, Ⅳ그룹인 가지산과 축령산 집단, Ⅴ그룹인 마니산 집단 등 5개 그룹으로 분류되었고, 지리적으로 인접 집단 간의 구분은 명확하게 이루어지지 않았다.
        154.
        2018.10 KCI 등재 서비스 종료(열람 제한)
        Background: The ginsenosides Rb1 (G-Rb1) and Rg1 (G-Rg1) are used as marker compounds, and are the principal bioactive compounds assessed in the quality control of white ginseng. This study was conducted to analyze white ginseng samples of different and to obtain useful data for the quality control of white ginseng. Methods and Results: The variation in the content of G-Rb1 and G-Rg1 was evaluated among 35 samples of 4-, 5-, and 6-year-old white ginseng. The content of both G-Rb1 and G-Rg1 did not significantly differ among ages, and the relative ratio of the maximum to the minimum content of these within ginseng of the same ages was more than two. However, the ratio of G-Rb1 to G-Rg1 content in the 5- and 6-year-old ginseng was significantly higher than that in the 4-year-old one. According to the ‘Ginseng industrial act’, the standard (w/w, %) minimum G-Rg1 and G-Rb1 content is 0.10% and 0.20% or more, respectively. Among the 35 samples examined, the content of G-Rg1 was found to be 0.124 - 0.399% with none being less than the standard level, while that of G-Rb1, was 0.147 - 0.595%, with 4 samples (11.4%) failing to meet the standard levels. The content of G-Rg1 and G-Rb1 did not show a constant relationship with the size of ginseng. Conclusions: In our study, the content of both G-Rg1 and G-Rb1 varied widely, and there was no significant difference among cultivation ages. The results of the present study might provide useful information for the quality control of raw ginseng and processed white ginseng using marker compound.
        155.
        2018.10 서비스 종료(열람 제한)
        Background : Carotenoids are pigments that are found in plants, fruits, bacteria, and fungi. β -carotene and canthaxanthin are orange pigments among thousands of carotenoids that possess potent antioxidant activity. The objective of this study was to determine β-carotene and cantaxanthin in 55 Kimchi cabbage germplasm using liquid chromatography mass spectrometry (LC-MS) method. Method and Results : 55 Kimchi cabbage accessions were sown in plug trays in the end of August, 2016. All the tissue samples were freeze-dried for 1 week and ground into fine powder and stored at -20℃ until analysis. Crude carotenoids from freeze-dried materials (100 mg) were extracted using 1 ㎖ of 100% (v/v) hexane in 10 minutes by using sonication bath followed by centrifugation. The average β-carotene contents was 1.43 ㎎·㎏-1 and ranged from 0.76 (IT 120045) to 2.25 ㎎·㎏-1 (IT 100378). The average canthaxanthin content in the entire domain of sample was 0.59 ㎎·㎏-1 with a range between 0.36 (IT 32746) and 1.08 ㎎․㎏-1 (IT 100386). Canthaxanthin content was significantly positively correlated with β-carotene (r = 0.65**) and leaf length (r = 0.63**). However, canthaxanthin was negatively correlated with cotyledon color (r = -0.41**). Principal component analysis results of the first two components (PC1 and PC2) explained 44.53% of the point variability. Conclusion : The resources with the highest β-carotene and canthaxanthin content are IT 100378, 100386, 100391, and 110828. This study could be useful to select a potential sources of health beneficial carotenoids (β-carotene and canthaxanthin) in Kimchi cabbage germplasm in nutraceutical formulations and for further applications as a breeding material and other research activities.
        156.
        2018.10 서비스 종료(열람 제한)
        Background : Alpha-linolenic acid is a type of omega-3 fatty acid and has been reported to be found at a remarkably high content in seeds of perilla (Perilla frutescens). The purpose of this study was to investigate the fatty acid compositions in 45 perilla accessions collected from Russia and recommend the potential genetic resources related to their fatty acid compositions. Methods and Results : The 45 accessions of perilla seeds which were collected from Russia were used for the study. Perilla seed oil was recovered using hexane in a soxhlet extraction method. The fatty acid compositions were analyzed using gas chromatography. The total oil content was ranged between 28.39 and 46.89%. The compositions of palmitic, stearic, oleic, linoleic and linolenic acid ranged from 5.57 to 7.09%, 1.16 to 2.27%, 11.83 to 19.55%, 11.92 to 16.71%, and 59.19 to 67.28%, respectively. Cultivars 'Dayu', 'Daeyu' and 'Anyu' showed lower linolenic acid composition compared to the average value of linoleic acid in perilla germplasms collected from Russia. Cluster analysis based on the fatty acid composition of the 45 perilla accessions segregated into three groups. Group Ⅰ characterized as higher palmitic, stearic and oleic acid compositions compared to other groups. Group Ⅱ which contained 12 accessions had high total oil and linoleic acid composition. Group Ⅲ characterized as a higher linolenic acid composition compared to other groups (p < 0.001). Oleic acid showed a significant negative correlation (r = -0.825) with linolenic acid. Principal component analysis (PCA) revealed that the first two principal components together explained 74.4% total variation. Conclusion : Our results indicated that accessions IT235818, IT235820, IT226739 which exhibited high linolenic acid composition could be useful to develop new functional vegetable oil materials.
        157.
        2018.05 서비스 종료(열람 제한)
        Background : Perilla (Perilla frutescens) seed oil is known to contain high omega-3 fatty acid than other plant oils. This study was aimed to investigate the fatty acid composition in seeds of 255 perilla accessions from South Korea and recommend the potential genetic resources rel ated to their fatty acid composition. Method and Results : Total oil was extracted by soxhlet extraction apparatus and the fatty acid compositions were analyzed by gas chromatography (GCMS QP2010 ULTRA, SHIMADZU, JP). Total oil contents ranged from 22.41 and 47.62% with an average content of 34.20%. Palmitic, stearic, oleic, linoleic, and linolenic acid contributed 4.46 to 7.67%, 1.64 to 4.11%, 9.15 to 26.39%, 11.89 to 28.76%, and 50.24 to 64.16% to the total oil content, respectively. Seeds from Jeollabuk-do showed the highest average total oil content (41.14%) compared to other regions (p < 0.05), while the linolenic acid composition was the highest in the samples from Chungcheongnam-do (59.48%) (p < 0.05). The cluster analysis segregated the perilla seed accessions into two major clusters. ANOVA revealed that there was a significant difference between group Ⅰ and group Ⅱ (p < 0.05). Group Ⅰ (86 accessions) characterized as higher palmitic, stearic, oleic, and linolenic acid compositions than group Ⅱ (169 accessions). The highest content of linolenic acid were recorded in accessions K126190, K135903, and IT283646 from group Ⅰ, and accessions IT108680, IT208894, and IT111050 from group Ⅱ had high total oil content. Linoleic acid content showed a strong negative correlation with palmitic acid (r = -0.726*) and oleic acid (r = -0.678*) content. Principal component analysis (PCA) revealed that the first two principal components together explained 68.75% total variation. Conclusion : Our results showed that accessions K126190, K135903, IT283646 which exhibited high linolenic acid composition and accessions IT108680, IT208894, IT111050 which exhibited high total oil composition, could be useful to develop new functional oil materials.
        158.
        2018.05 서비스 종료(열람 제한)
        Background : Perilla leaves (Perilla frutescens) are known to possess antioxidant activity and have long been used to treat a variety of health related issues. The present study was conduct ed to compare the antioxidant activity among perilla accessions collected from Russia. Method and Results : The leaves of a total of 46 accessions of perilla were collected from Russia. Crude extracts were obtained from 2 g of oven-dried perilla leaves using ASE-350 extractor. Total phenolic content (TPC) was determined by Folin-Ciocalteu method and antioxidant activities were estimated by 2,2-diphenyl-1-picryl-hydrazil (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (A BTS) radical scavenging activities, ferric reducing antioxidant power (FRAP) and reducing power (RP). TPC was ranged from 88.70 to 148.85 ㎍ gallic acid equivalent (GAE) /㎎ dried extract (DE). DPPH, ABTS, FRAP, and RP were ranged from 59.49 to 94.80 ㎍ ascorbic acid equivalent (ASCE) /㎎ DE, 73.01 to 190.59 ㎍ ASCE /㎎ DE, 98.73 to 326.39 ㎍ ASCE /㎎ DE, 82.58 to 264.88 ㎍ ASCE /㎎ DE, respectively. Cluster analysis based on antioxidant assay results of 46 perilla accessions divided into three major groups. Group Ⅰ (9 accessions) characterized as higher antioxidant activity accessions than other group (p < 0.001). The correlations between antioxidant assays were strong and positive (r ≧ 0.78). Principal component analysis (PCA) revealed that the first two principal components together explained 92.96 % total variation. Conclusion : Among the perilla accessions collected from Russia, group accessions clustered in group Ⅱ showed high antioxidant activity. Our results indicated that accessions IT274300, IT226732 and IT274293 could be used as a source of valuable natural antioxidant materials.
        159.
        2017.06 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to analyze seasonal and annual variations in rice quality and factors affecting the quality, for quality evaluation of the brand rice varieties produced in Jeonnam region. Coefficient of variation (CV) values for the seasonal variation in the rice quality were 3.1% in Toyo value, 2.1% in whiteness, 1.6% in protein content, 1.0% in moisture content, and 0.4% in head rice ratio. Quality characteristics of the brand rice varieties generally showed a decreasing tendency after April, as the months progressed. CV values for the annual variation in the rice quality were relatively high at 5.6% in protein content and 5.2% in Toyo value whereas those for whiteness and head rice ratio were relatively low, at 2.7% and 1.8%, respectively. Palatability and protein content showed high correlations with minimum air temperature, sunshine hours, rainfall, and daily temperature range. Head rice ratio had a negative correlation with daily temperature range whereas chalky rice ratio had a positive correlation with rainfall. Based on these results, we formulated a multiple regression equation to estimate palatability of cooked rice using protein content, whiteness, head rice ratio, and moisture content as follows:y =-6.71a + 2.27b + 1.29c + 0.51d - 15.34 (R2=0.51*)(y: palatability of cooked rice, a: protein content, b: moisture content, c: whiteness, d: head rice ratio).
        160.
        2017.05 서비스 종료(열람 제한)
        Background : To select plant resources of the possibility of development as a natural antioxidant, the antioxidant activities including total polyphenol content (TPC), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picryl-hydrazil (DPPH), ferric reducing antioxidant power (FRAP) and reducing power (RP) of perilla accessions collected from South Korea were conducted. Method and Results : A total of 18 perilla accessions by regions were selected. Two grams of dried perilla leaves were extracted with 85% ethanol and used for analysis of antioxidant activity. Antioxidant activity value was measured in a spectrophotometer. Perilla extracts showed variation in TPC ranging from 30.87 to 92.66 ㎍ GAE ㎎-1 dw. ABTS, DPPH, FRAP and RP ranged from 6.83 to 38.64 ㎍ Trolox ㎎-1 dw, 0.63 to 8.62 ㎍ ASC ㎎-1 dw, 5.05 to 17.57 ㎍ ASC ㎎-1 dw, and 4.52 to 35.69 ㎍ ASC ㎎-1 dw, respectively. TPC was high in perilla leaves of Gyeongsang-do, but other antioxidant activities were high in perilla leaves of Chungcheong-do. Cluster analysis based on antioxidant acitivities of 18 perilla accessions consist of group Ⅰ (3 accessions), Ⅱ (2 accessions), Ⅲ (5 accessions) and Ⅳ (8 accessions). Group Ⅱ characterized as higher antioxidant activities than other groups. Principal component analysis (PCA) based on antioxidant data revealed that the first two principal components (PC1 and PC2) together explained 97.78 % total variation. Conclusion : IT242410 and IT235354 of group Ⅱ showed high antioxidant activity. These resources will be useful for developing natural antioxidants.