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        검색결과 222

        43.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to assess knee joint loading in the target knee during a golf swing compared to loading rates of high impact activities such as cutting and drop landings. Nine healthy competitive golfers completed golf swings with the target foot both straight and externally rotated 30 degrees, as well as drop landings and cutting maneuvers. Motion capture data was collected at 240 Hz and ground reaction force data was collected at 2400 Hz. The frontal and transverse knee moments were examined using repeated measures ANOVA through SPSS. The abduction moments were higher in golf swings as compared to the other high impact activities (p=.010), while the external rotation moments were lower (p=.003). There were no significant differences between externally rotated and neutral golf swings. These results suggest moments applied to the knee during a golf swing are similar to those applied during a high impact activity.
        4,000원
        44.
        2019.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Single crystals, which have complexed composition, are fabricated by solid state grain growth. However, it is hard to achieve stable properties in a single crystal due to trapped pores. Aerosol deposition (AD) is suitable for fabrication of single crystals with stable properties because this process can make a high density coating layer. Because of their unique features (nano sized grains, stress inner site), it is hard to fabricate single crystals, and so studies of grain growth behavior of AD film are essential. In this study, a BaTiO3 coating layer with ~ 9 μm thickness is fabricated using an aerosol deposition method on (100) and (110) cut SrTiO3 single crystal substrates, which are adopted as seeds for grain growth. Each specimen is heat-treated at various conditions (900, 1,100, and 1,300℃ for 5 h). BaTiO3 layer shows different growth behavior and X-ray diffraction depending on cutting direction of SrTiO3 seed. Rectangular pillars at SrTiO3 (100) and laminating thin plates at SrTiO3 (110), respectively, are observed.
        4,000원
        46.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Safety-related cabinets and their electrical parts, such as relays and switches in nuclear power plants, should maintain continuous functioning, as well as structural safety according to the nuclear regulatory guidelines. Generally, an electrical part is qualified if its functioning is maintained without abnormality during excitement by motion compatible with the test response spectrum, which is larger than its in-cabinet response spectrum (ICRS). ICRS can be determined by shake-table test or dynamic analysis. Since existing cabinets in use can hardly be stopped and moved, dynamic analysis is preferred over shake-table test in determining ICRS. The simple method, suggested by the Electric Power Research Institute (EPRI) to determine ICRS, yields conservative or non-conservative results from time to time. In order to determine that the ICRS is better than EPRI method in a simple way, Ritz method considering global and local plate behaviors was suggested by Gupta et al. In this paper, the Ritz method is modified in order to consider the rocking and frame behaviors simultaneously, and it is applied to a simple numerical example for verification. ICRS is determined by Ritz method and compared with the results by finite element method (FEM). Based on this numerical example, recommendations for using Ritz method are suggested.
        4,000원
        49.
        2018.11 구독 인증기관·개인회원 무료
        폴리벤즈이미다졸(PBI)는 현재 상용 고분자들 중에서 가장 내열성이 좋은 이종고리화합물이다. 우수한 기계적, 화학적 물성 때문에 해당 고분자는 나노공학, 전기공학, 광학, 재료공학과 같은 분야 외에도 쓰임새가 다양하다. 본 연구는 폴리벤즈이미다졸 지지체를 제조하기 위하여 전기방사를 이용하였다. PBI 방사 용액의 용매로서 DMAc를 사용하였고, LiCl은 안정제로써 사용하였다. 또한 다양한 전기방사의 조건을 변화시킴에 따라 나타나는 모폴로지를 관찰하고자 하였다. 또한, DBX를 이용한 가교반응을 통하여 보다 화학적으로 강화된 필름을 제조하였다. 나노 섬유의 화학 구조와 성분은 FT-IR와 DSC를 통해 확인하였다. 전기방사 섬유의 모폴로지는 SEM을 통해 확인하였다.
        50.
        2018.11 구독 인증기관·개인회원 무료
        Polymer electrolyte membrane fuel cells (PEMFCs) have been studied intensively due to their great potential as a clean and efficient energy conversion device. Especially, considerable attention has been paid to the development of thin polymer electrolyte membranes (PEMs) for the practical application of PEMFCs. However, thin PEMs normally have poor physicochemical stability. It is well-known that the physicochemical stability of polymer membrane can be improved by cross-linking technology. In this presentation two different types of cross-linked membranes from sulfonated poly(arylene ether sulfone) (SPAES) will be introduced: 1) cross-linked SPAES membranes prepared using flexible perfluoropolyether as a cross-linker. 2) End group cross-linked SPAES membranes prepared via simple thiol-ene click reaction.
        54.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate effects of feeding fermented milk on growth, intestinal microorganisms and fecal noxious gas emission in suckling pigs. A total of a hundred birth piglets (Landrace×Yorkshire×Duroc) were randomly assigned into feeding group and control group during suckling period that ten pigs per sow. Fermented milk contained 3.0×108/g of Bacillus and 3.5×108/g of Lactobacillus, and was supplied by top dressing method. Fermented milk fed to the sulking pigs indicated tendency to increase weaning body weight (p=0.052) and average daily gain (p=0.094). Total microbial flora and Escherichia coli in the feces were lower (p<0.05) in the feeding group than the non-feeding group. Reversely, Lactobacillus was higher (p<0.01) in feces of the pigs fed fermented milk than the pigs of the control group. Hydrogen sulfide emitted in feces was decreased in feeding group compared with control group (p<0.05). Similarly, fecal total mercaptans was diminished in the feeding group than the control group (p<0.01). Therefore, the fermented milk fed to the sulking pigs may improved growth and can influence positively intestinal microorganisms and fecal noxious gas emission.
        4,000원
        55.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 고온기 때 사료 내 다른 에너지 수준 및 비테 인 첨가 급여가 육성돈의 영양소 소화율 및 생리학적 변화 에 미치는 영향을 구명하기 위해 실시하였다. 실험동물은 삼원교잡종(L×Y×D; initial body weight, 73.5±0.5kg) 거세 수퇘지 12두를 사용하였고 대사틀에 배치하였다. 실험기간 은 고온기인 7~8월에 실시하였다. 실험계획은 에너지 2수 준(3,300 및 3,400kcal/kg)과 비테인 2수준(0 및 0.5%)이며 4×4 Latin square로 하였다. 조단백질 소화율은 고에너지 사료(3,400kcal/kg)가 저에너지 사료보다 유의적으로 높았 다(p<0.01). 그러나, 비테인급여는 영양소소화율에 영향을 미치지 않았다. 혈액생화학적 분석 결과에서는 에너지 수 준 및 비테인 첨가가 육성돈 내 생리적 변화를 보이지 않 았다. 면역반응을 나타내는 혈중 IgG에서는 고에너지 사료 가 저에너지사료보다 높았으나(p<0.05) 스트레스 지표를 나타내는 cortisol농도에서는 차이가 나지 않았고, 비테인 첨가급여는 IgG 및 cortisol 농도 변화를 나타내지 않았다. 결론적으로 사료 내 비테인 첨가급여보다 에너지 수준을 높이는 것이 돼지 체내에 더 긍정적인 효과를 보이며, 여 름철 고온스트레스를 받는 돼지 사료 내 고에너지를 급여 했을 때 어떠한 결과가 나오는지 추후 더 연구해 볼 만한 것으로 사료된다.
        4,000원
        56.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this experiment was to evaluate the effect of Chamaecyparis obtus extract to reduce odor emissions released from the swine feeding operations. Finisher pigs [Landrace × (Yorkshire × Duroc)] with an initial body weight averaging 50 kg were housed separately in two rooms with eighty eight pigs in each room at a swine feeding operation site. C. obtus extract was sprayed in the room by ceiling sprayer for one minute at twice per day during two months. Concentrations of odorous compounds from air in the room of the swine feeding operation were analyzed at four times during two months. Levels of butyric acid, valeric acid, i-butyric acid, ivaleric acid, skatole, methylmercaptan, and trimethylamine tended to decrease in C. obtus extract spray treatment group compared to the non-spray treatment group (P > 0.05). Odor activity values of butyric acid, valeric acid, skatole and trimethylamine were higher than other odorous compounds and decreased by 72%, 76%, 54% and 20%, respectively, in C. obtus extract spray treatment group compared to the non-spray group. Taken together, C. obtus extract showed an odor reducing capability in the air of a swine feeding operation suggesting that it possesses anti-bacterial properties as well as having a dust removal and masking effect.
        4,000원
        57.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 2010년 여름에 천수만에서 저층해수를 채집하여 용존산소와 영양염 농도를 측정하였다. 또한 benthic chamber내의 해수시료를 시계열로 채집하는 자동화된 Benthic Lander를 설치하여 해수-퇴적물간 영양염 플럭스를 측정하였다. 오염된 인공호수 유출수가 들어오는 천수만 북쪽에서는 저층수의 용존산소는 2 mg/l로 hypoxia의 존재 가능성이 확인되었다. 반면 남쪽 천수만 입구의 저층 용존산소는 5 mg/l이었다. 영양염은 용존산소와 반대의 분포 경향을 보였고, N/P ratio의 변화는 hypoxia에 의해 발생된 인산염의 탈착과 용출 때문으로 보인다. 만 북쪽 해역의 유기탄소 산화율과 산소소비율은 남쪽 만 입구 해역보다 약 2배 큰 값을 보였고, 영양염 benthic flux는 천수만 북쪽에서 4내지 6배 높았다. 이러한 결과는 해수-퇴적물간 물질 플럭스를 정확히 추정하기 위해서는 hypoxia의 역할에 대한 이해가 중요하다는 점을 시사해준다.
        4,000원
        59.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to evaluate the effect of size and depth of cavities on the pavement failure using the full-scale accelerated pavement testing. METHODS: A full-scale testbed was constructed by installing the artificial cavities at a depth of 0.3 m and 0.7 m from the pavement surface for accelerated pavement testing. The cavities were made of ice with a dimension of 0.5 m*0.5 m*0.3 m, and the thickness of asphalt and base layer were 0.2 m and 0.3 m, respectively. The ground penetrating radar and endoscope testing were conducted to determine the shape and location of cavities. The falling weight deflectometer testing was also performed on the cavity and intact sections to estimate the difference of structural capacity between the two sections. A wheel loading of 80 kN was applied on the pavement section with a speed of 10 km/h in accelerated pavement testing. The permanent deformation was measured periodically at a given number of repetitions. The correlation between the depth and size of cavities and pavement failure was investigated using the accelerated pavement testing results. RESULTS : It is found from FWD testing that the center deflection of cavity section is 10% greater than that of the intact section, indicating the 25% reduction of modulus in subbase layer due to the occurrence of the cavity. The measured permanent deformation of the intact section is approximately 10 mm at 90,000 load repetitions. However, for a cavity section of 0.7 m depth, a permanent deformation of 30 mm was measured at 90,000 load repetitions, which is three times greater than that of the intact section. At cavity section of 0.3 m, the permanent deformation reached up to approximately 90 mm and an elliptical hole occurred at pavement surface after testing. CONCLUSIONS : This study is aimed at determining the pavement failure mechanism due to the occurrence of cavities under the pavement using accelerated pavement testing. In the future, the accelerated pavement testing will be conducted at a pavement section with different depths and sizes of cavities. Test results will be utilized to establish the criteria of risk in road collapse based on the various conditions.
        4,000원
        60.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For evaluating the boar semen quality, sperm motility is an important parameter because the movement of sperm indicates active metabolism, membrane integrity and fertilizing capacity. Phospholipase C zeta (PLCz) is important enzyme in spermatogenesis, but the effect has not been confirmed in pigs yet. Therefore, this study was aimed to analyze their association with sperm motility and kinematic characteristics. DNA samples from 124 Duroc pigs with records of sperm motility and kinematic characteristics [total motile spermatozoa (MOT), curvilinear velocity (VCL), straight-line velocity (VSL), the ratio between VSL and VCL (LIN), amplitude of lateral head displacement (ALH)] were subjected. A SNP in non-coding region of PLCz g.158 A > C was associated with MOT (p < 0.05), VCL (p < 0.01), LIN (p < 0.01) and ALH (p < 0.05) in Duroc population. Therefore, we suggest that the intron region of the porcine PLCz gene may be used as a molecular marker for Duroc boar semen quality, although its functional effect was not defined yet. Whether the association is due to the candidate gene or not require further verification. Thus, it will be of interest to continue association studies in the regions surrounding those genes.
        4,000원
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