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        검색결과 223

        2.
        2023.04 구독 인증기관·개인회원 무료
        12.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study conducted finite element analysis in advance to understand the natural frequency, con-ducted static structural analysis and analyzed stress behavior occurring on the boundary of wheel and rail when passing the straight line and curve line. According to the FEA, the wheel had natural frequency of 1st mode 238.4Hz to 10th mode 1,320Hz, and the rail had natural frequency of 457.4Hz to 619.7Hz. When looking at the correlated frequency range, the natural frequency of 4th~6th mode of wheel and 3rd~9th mode of rail track were correlated. As for the result of stress behavior translation occurring on the boundary of wheel and track, it was 53.4MPa when passing the curve line, which was 16MPa higher than when passing the straight line.
        4,000원
        13.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was aimed to determine the effects of hybrid and inoculant on in vitro rumen digestibility and rumen fermentation indices of corn silage. Two corn hybrids(Kwangpyeongok (KW) vs. Pioneer 1543(PI)) were ensiled for 100 days with two inoculants(L. plantarum(LP) vs. L. buchneri(LB)) applied at 1.2 × 105 cfu/g of fresh forage. Silages were incubated in rumen fluid medium at 39℃ for 72 hours. Both of KW and PI had no difference(p>0.05) on in vitro digestibility of dry matter(IVDMD) and neutral detergent fiber(IVNDFD), while application of LB produced higher(p<0.05) IVDMD and IVNDFD than LP. Hybrid and inoculant applications did not affect(p>0.05) total gas volume, ammonia-N, total VFA, and acetate concentrations in the rumen. Applied LB was higher(p<0.05) propionate concentration than LP, while hybrids had no effect(p>0.05). Furthermore, the interaction effect(p<0.05) was occurred in propionate concentration. Butyrate concentration did not affected(p>0.05) by hybrid and inoculant applications, but there was an interaction effect between hybrid and inoculant(p<0.05). Applications of hybrid and inoculant had effects(p<0.05) on iso-butyrate and valerate, without any interaction effects(p>0.05). This study concluded that application of KW and PI has no effects on in vitro rumen digestibility and rumen fermentation indices of corn silage, while application of LB increase the rumen digestibility in both of corn hybrids.
        4,000원
        14.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        By analyzing the status of Korean tire labeling regulation and comparing the performance indicators of tire labeling in different countries, this paper expounds the serious impact of tire noise on traffic noise pollution, and puts forward that in order to improve the comfort of car ride, control traffic noise pollution and build a green tire industry, the tire labeling system should be improved, and the corresponding requirements for tire rolling noise should be put forward according to the road conditions in Korea.
        4,000원
        15.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study on the tire noise due to the On-Board Sound Intensity test method. The object of this project is to prepare the countermeasure of the noise reduction according to collect tire/road noise data under various influencing factors by using On-Board Sound Intensity test method. To accomplish the object ; A automotive is used as a test platform to test tire/road noise by changing different types of tires and using On-Board Sound Intensity test system. The influence of inflation pressure, road, load, speed and pattern type on tire/road noise is compared and analyzed. At the same time, the mechanism of tire/road noise is analyzed, which provides a experimental basis for tire noise reduction.
        4,000원
        16.
        2018.11 구독 인증기관·개인회원 무료
        To preserve the superior genetic resources and restore the endangered species, Somatic cell nuclear transfer (SCNT) has been used widely. In Korea, the research of dog cloning has made outstanding achievements including the production of the world`s first cloned dog. Sapsaree (Sapsalgae), the representative dog of Gyeongsan-si was designated as a Korea natural monument (No. 368). This male dog used in this study has azoospermia due to unknown cause. In this study, the aim was to confirm the cause of infertility in the cell donor dog and to evaluate the reproduction potential of dog cloning using infertile male dog by SCNT. First, to confirm the infertility of the cell donor dog, the reproductive history and the testis were evaluated. The breeding histology was not recorded in individual document. In histopathology, the Sertoli cell tumor was confirmed in biopsy of the cell donor dog after death. But, these tumors are predominantly in older dogs. Second, we produced the cloned dogs with the somatic cells of the infertile dog and the appearance was similar with the cell donor dog. Also, microsatellite analysis confirmed the genetic relationship between the cell donor and clone dogs. Third, the potential breeding capacity of the cloned dog was confirmed. In T4 assay, the normal dog (same age with cloned dogs), cell donor dog, and cloned dogs was investigated. The cell donor dog with azoospermia had very low T4 level, and cloned dogs showed higher level of T4 than normal dogs. In CASA, There was no significant difference in sperm motor ability between normal dogs and cloned dogs. As a result, cloned dogs produced by SCNT had no problem regarding the reproductive function of the testis. In AI experiment, the semen of clone dogs was used to fertilize a natural female bitch and was diagnosed pregnancy by ultrasonography. In total, 7 puppies were born by normal delivery (male: 3, female: 4). In conclusion, this study confirmed that the reproduction problem of non-genetic infertility can generate a normal descendant by SCNT. Also, the first successful research to restore infertile dogs was completed. Furthermore, SCNT would be useful for the restoration of endangered species and application of superior traits.
        19.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the effect of new inoculants on in vitro digestibility and fermentation characteristics of high moisture rye silage. Rye was harvested at heading stage and divided into 5 treatments, following: No additives(CON); L. plantarum R48-27(NI1); L. buchneri R4-26(NI2); mixture of NI1 and NI2 at 1:1 ratio(MIX); and L. buchneri(LB). The rye forage was ensiled into 10 L bucket silo for 100 days. In vitro digestibility of dry matter and neutral detergent fiber were highest(p<0.05) in NI2 silage. The pH in NI2 and LB silages were lower(p<0.05) than CON silage. Lactate concentration was highest(p<0.05) in NI1 silage. While concentrations of acetate and propionate were highest(p<0.05) in MIX silage. Lactates : acetate ratio was highest(p<0.05) in NI1 silage, but lowest in LB silage. Butyrate concentrations of NI2 and LB silages were lower(p<0.05) than that in CON and NI1 silages. Lactic acid bacteria (LAB) count in all inoculated silages was higher(p<0.05) than that in CON silage, while yeast count in LB silage was lower than in CON, NI1, and MIX silages. In conclusion, application of NI2 inoculant could improve potentially fermentation quality and digestibility of high moisture rye silage.
        4,000원
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