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        검색결과 124

        41.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was carried out to investigate the effect of harvesting time of Italian ryegrass (Lolium multiflorum Lam; IRG) in spring on dry matter (DM) yield. IRG cultivars ‘Kowinearly’ and ‘Greenfarm’ were seeded at 50 kg/ha and grown on rice paddy fields. There was no difference in growth characteristics between both varieties before winter. However, cold tolerance of Kowinearly was higher than that of Greenfarm, as demonstrated by post-wintering growth characteristics. The heading date of both varieties was affected by the spring weather. The IRG was harvested three times at 5-day intervals beginning from 9 May. The DM yield of Greenfarm was 6,306; 7,335; and 8,109 kg/ha, and that of Kowinearly was 7,498; 9,196; and 10,449 kg/ha at the three consecutive harvests. The delay of the harvesting time for 5 and 10 days increased the DM yield of Greenfarm by 16% and 29% and that of Kowinearly by 23% and 39%, respectively, compared to the yield at first harvest (p < 0.05). Therefore, IRG harvest later than early to mid-May is expected to increase productivity. The feed values of Greenfarm were: 12.2% of crude protein (CP), 34.5% of acid detergent fiber (ADF), 57.7% of neutral detergent fiber (NDF), 61.6% of total digestible nutrients (TDN), and 72.3% of in vitro DM digestibility (IVDMD). For Kowinearly, these values were 16.4% of CP, 30.4% of ADF, 52.7% of NDF, 64.9% of TDN and 79.0% of IVDMD.
        4,000원
        42.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study investigated the effects of different seeding rates on growth characteristics and seed productivity of the “Kowinearly” cultivar of Italian ryegrass (Lolium multiflorum Lam.) in paddy fields. Sowing Kowinearly in paddy fields under growing rice at the rates of 20, 30, 40, and 50 kg/ha resulted in seed yields of 1.57, 1.92, 2.06, and 2.09 ton/ha, respectively. Seed yield of Kowinearly was the highest at a seeding rate of 50 kg/ha (p<0.05), at which the cultivar was able to survive in winter and the weed ratio was low. Under these conditions, most growth characteristics such as winter survival (85%), weed ratio (10%), stems per square meter (1,006) were superior than those sown at other seeding rates (p<0.05). In addition, it has been reported that the economic efficiency of the 50 kg/ha seeding rate was higher than that of the other seeding rates.
        2,000원
        44.
        2015.10 구독 인증기관·개인회원 무료
        Butterflies are commonly used for environmental monitoring to assess biodiversity changes in the world. Occurrence of butterflies were monitored by a line transect method in Gwangneung forest for 10 years from 2005 to 2014. Totally, 8,484 individuals of 96 species of butterflies were identified. Among them, two species Libythea celtis (2807 individuals) and Pieris melete (1517 individuals) were the most abundant species, followed by Argynnis paphia (381 individuals) and Neptis philyroides (277 individuals). Meanwhile, Pieris melete and Libythea celtis showed high occurrence frequency with 84.6% (99 times among the 117 monitoring times) and 76.9% (90 times) respectively, followed by Argynnis paphia (42.7%) and Pieris canidia (40.2%). Species richness and abundance were varied at different years, and they were slightly decreasing in recent years. Most species showed annual variation in their abundance. Species abundance distribution model showed a log-normal distribution.
        45.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted from October 2014 to May 2015 to explore forage production and feed values of Italian ryegrass, Rye and whole crop barley as winter forage crops in the Southern region of Korea. The experimental location was over 10 points for each species and each sampling point area was 1 m² (Width: 1 m × Length: 1 m). Air mean temperature and rainfall in the Southern region of Korea during the experimental period was 6.95 ± 5.75℃ and 70.45 ± 54.68 mm, respectively. Fresh forage yield of Italian ryegrass, the most cultivated forage in the Southern region of Korea, was 44.4 ± 7.0 ton/ha. The percentage of dry matter for whole crop barley was 28.9 ± 7.0%. Crude protein (CP) was higher in Italian ryegrass (10.7 ± 5.3%) while total digestible nutrient (TDN) had the highest value in whole crop barley. Crude protein was not significantly different by location. However, the neutral detergent fiber (NDF), acid detergent fiber (ADF) and total digestible nutrient value of forage from Jeonbuk province were higher than in forage from Gyeongnam province.
        4,000원
        46.
        2015.04 구독 인증기관·개인회원 무료
        Distribution and abundance of species are influenced by their environmental condition. Among various environmental factors, a vegetation is one of the most influential factors, because it is used as habitats as well as food resources. Arthropods including insects play a important role in forest ecosystems as grazers, scavenger, predators, etc. Deciduous and coniferous forests have different plant community composition, resulting in different environmental condition. In this study, we collected arthropod communities at two different deciduous and coniferous forest stands in the Mountain Gariwang. At each stand, three different sampling methods were used: soil core for soil macroinvertebrate, pitfall trap for wandering insects, and sweeping net for insects in the shrups. Therefore, sampling was conducted at vertical habitats in the forest. The results showed that there were no difference in the number of orders from soil at both coniferous and deciduous stands. However, the abundance was higher at coniferous stand than at deciduous stand. Collembola was the dominant taxa in soil. Meanwhile, there were no statistically significant differences of community composition between coniferous stand and deciduous stands. Multivariate analyses was conducted to characterize differences of communities at different stands as well as vertical distribution in forest.
        47.
        2015.04 구독 인증기관·개인회원 무료
        Pogonini Laporte, 1834 is one of the tribes in Trechinae Bonelli, 1810 (Coleoptera: Carabidae). This tribe is morphologically similar to Trechini, Benbidiini, Zolini and Patrobini of the subfamily. However, Pogonini can be distinguished from the other tribes by having a combination of the following characters: apical maxillary palpomere fusiform; umbilical series of setae on elytron more or less contiguous (though sparse in middle); each tarsomeres with a median sulcus on dorsal side. Pogonini includes about 85 species of 12 genera worldwide and is found in all zoogeographical regions of the world. Many species inhabit along the sea coasts or near salt lakes, and are recognized as halobiont. In Korea, Paik (1998) reported Pogonus (Pogonus) itoshimaensis Habu, 1954. However, he added only the species name in the checklist without description or illustration although few specimens were examined. After Paik’s study, any studies on taxonomic status and distribution of Korean Pogonini have not been carried out. The genus Pogonus Dejean is the largest group in Pogonini with two subgenera: P. (Pogonoidius Carret, 1903) and P. (Pogonus Dejean, 1821). These two subgenera share very similar external morphological characters; Pogonoidius has setae on anterior angles of pronotum and setae at 7th interval of elytra while Pogonus does not have them. In the present study, two species, Pogonus (Pogonus) japonicus Putzeys, 1875 and P. (Pogonoidius) punctulatus Dejean, 1828, are newly recognized from Korea. A key to the Korean Pogonini species, redescription, distribution, photos of diagnostic characters, and illustrations of male and female genitalia are provided.
        48.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effects of the amount of nickel powder (Ni) in Ni-carbon fiber (CF) hybrid filler systems on the conductivity(or resistivity) and thermal coefficient of resistance (TCR) of filled high density polyethylene were studied. Increases of the resistivity and TCR with increasing Ni concentration at a given hybrid filler content were observed. Using the fiber contact model, we showed that the main role of Ni in the hybrid filler system is to decrease the interfiber contact resistance when Ni concentration is less than the threshold point. The formation of structural defects leading to reduced reinforcing effect resulted in both a reduction of strength and an increase of the coefficient of thermal expansion in the composite film; these changes are responsible for the increases of both resistivity and TCR with increasing Ni concentration in the hybrid filler system.
        4,000원
        52.
        2012.06 구독 인증기관·개인회원 무료
        This study was to analyse the usability of morphological evaluation of vitrified-thawed oocyte before somatic cell nuclear transfer (SCNT) using Oosight imaging system to show spindle. For the vitrification, in vitro matured bovine MII oocytes were treated by two-step freezing medium without (control group) or with 5 ug/ml cytochalasin-b (CCB group). In Exp. 1, after thawing, recovered oocytes in each treatment group were assessed by live image using Oosight imaging system or/and cytoskeletal protein image using immunostaining. In Exp. 2, in each treatment group the in vitro developmental potential of frozen-thawed bovine oocytes post evaluation using Oosight imaging system and then SCNT was investigated. The SCNT embryos were cultured in CR1aa medium supplemented with 10% FBS, 1 mM EGF and 1 mM IGF at 38.5 C in 5% O2 and 5% CO2 in air for 8 days. In Exp.1, the rates of in vitro survival, morphological good grade and spindle normality of CCB treatment group (91.1%, 54.2% and 55.5%) were better than those of control group (86.1%, 48.5% and 48.5%). After SCNT using vitrified-thawed oocyte, the rates of fusion, reconstructed embryos and blastocyst development were also high in CCB treatment group (66.6%, 36.4% and 3.0%) than control group (60.0%, 27.3% and 0%). These results demonstrated that the identification of morphological spindle image of the vitrified-thawed bovine oocytes using Oosight imaging system helps to predict the SCNT embryo quality.
        53.
        2011.10 구독 인증기관·개인회원 무료
        Somatic cell nuclear transfer (SCNT) is an efficient technique which has been successfully applied to developmental biology, and resulted in the production of offspring from various species. It offers many opportunities in basic and medical research as well as endangered species preservation. On the other hand, embryonic stem (ES) cells are useful research tools for genetic engineering and developing disease models. In previous study, we established bovine IVF embryo derived ES cell line which can be grow indefinitely as undifferentiated cell state. In this study, we compared the effect of two different age cells (bovine ES cell; JNU-ibES-05 or adult ear fibroblast cell) on in vitro developmental potential of bovine SCNT embryo. To produce SCNT embryos, the ES cells or somatic cells were dissociated and transferred into enucleated MⅡ oocytes, and cleaved reconstructed embryos were cultured in CR1aa medium containing 10% FBS, 1 ug/ml epidermal growth factor (EGF) and 1 ug/ml insulin growth factor (IGF) for 8 days. In the result, blastocyst development rate was similar between ES cell treatment group and somatic cell treatment group, 27.7% (10/36) and 28.9% (11/ 38), respectively. However, there was particular difference in development speed from day 5 post SCNT, blastocyst expanding was 1 day faster in ES cell group than in somatic cell group. This difference was analyzed by semi-quantitative RT-PCR using pluripotency, growth and cell cycle gene markers. These results demonstrated that SCNT embryo using ES cell as a donor cell has better growth potential than somatic cell, and it will be a useful tool for a transgenic animal production.
        60.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We prepared the amine epoxy adducts (AEA)/thin multiwalled carbon nanotubes (TWCNTs) composite particles using nonsolvent based methods including dry mechano-chemical bonding(MCB) process and supercritical fluid (SCF) process. The resulting TWCNTs/AEA composite particles have been used as curing agents for urethane modified bispheol A type epoxy resin. The thermal, thermomechanical properties of the epoxy resins cured with TWCNTs/AEA composite particles were measured by DMA and the dispersion of CNT was characterized by SEM. Because of high degree of CNT dispersion, thermal and mechanical properties of the epoxy resin cured with TWCNTs/AEA composite particles prepared by SCF process are better than those cured with mechano-chemically prepared TWCNTs/AEA composite particles.
        4,000원
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