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        검색결과 212

        83.
        2016.10 구독 인증기관·개인회원 무료
        난자생검(Ovum pick up, 이하 OPU) 기법은 유효축군 조기확보 및 우수한우 유전자 원의 조기증식, 희소유전자원 다량확보를 위해 매우 중요한 기법으로 주목받고 있다. 이 러한 OPU기술에는 체외배양기술 외에도 현장의 환경과 시기에 따라 회수되는 난자의 수 역시 중요하다. 현재, 가축센터에서는 한우의 유전자 다양성 확보를 위한 일반 한우 외에 도 희소한우 증식을 위한 연구를 진행 중에 있다. 본 연구는 OPU기법을 활용하여 가축 유전자원센터에서 보유중인 한우 또는 칡소를 대상으로 계절별 및 모색별로 난포란의 개 수와 난자회수율의 차이를 비교 · 검토하고자 실험을 진행하였다. 실험시기는 3월에서 5 월(봄), 6월에서 8월(여름), 9월부터 11월(가을)까지 구분하여 실시하였으며, 계절별 및 모 색별로 채취되는 난자의 개수와 회수율을 분석을 하였다. 봄에는 8.20±6.57, 여름에는 5.47±4.01, 가을에는 5.88±3.65개가 회수되었으며, 또한 계통별로는 가을에 실시한 결과 한 우는 6.40±6.15개, 칡소는 2.75±0.55개가 회수되었다. 그리고, 계통별로 수정란발달률은 한 우는 난할률이 25.0±44.4%, 배반포발달률이 6.3±50.0%, 칡소의 경우 난할률이 27.3±21.0%, 배반포발달률이 9.1±16.7%로 나타났다. 계절별로 OPU를 실시한 결과 여름, 가을경에 실 시하는 것에 비해서 봄에 실시를 하였을 경우 회수되는 난자의 수가 많은 것으로 확인을 하였다. 그리고, 현재 일반한우가 칡소에 비해서 회수되는 난자가 더 많은 것으로 확인되 었다. 이에 반하여 난할률 및 배반포발달률은 차이가 없는 것으로 확인되었으나, 향후 실 험진행에 따라 정확한 결과를 도출할 것으로 사료된다.
        84.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Historically, Korea old cattle had been consisted with various lines of coat color brindle, black and white-brown breeds or more. The two rare lines of black and white coat color are maintained for animal resources and preserved critically. The present study was carried out to evaluate potential usage of cysteamine supplementation during in vitro matration (IVM) and in vitro culture/production of embryo (IVP) by transvaginal ultrasound-guided follicle aspiration (Ovum Pick-Up: OPU) for the establishment of cryo-banking system. Immature slaughterhouse-derived cumulus-oocyte complexes (SL-COCs) were matured in IVM medium supplemented with 0, 0.1, 0.3 or 0.9 mM cysteamine, and then cultured in mSOF-BAS for 8 days after in vitro fertilization. The treatment of 0.1 mM cysteamine on SL-COCs showed higher rate of blastocyst, so OPU-derived COCs from rare breeds were matured in TCM media supplemented with or without 0.1 mM cysteamine, FSH and 5% FBS. The embryos were evaluated their developmental stages on day 8. During IVM, cysteamine treatment significantly increased the embryo production rate of slaughterhouse-derived COCs (19.6% vs. 30.5%). The presence of cysteamine during IVM of OPU-derived COCs from rare Korean cattle breeds (albino white and black line) also increased embryo production rates than those from SL-COCs (27.4% vs. 41.9% and 36.4%). With these results, cysteamine treatment during IVM is one of key factors IVP of blastocysts to establish banking system of endangered rare Koarean cattle with OPU derived transferable blastocysts.
        4,000원
        85.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        During the ovary preservation in low temperature, the cumulus oocyte complexes(COCs) lose their developmental competences after in vitro fertilization. We used phosphate-buffered saline (PBS) as a basic solutions of at various temperatures (25, 15 or 5 ℃) and supplemented them with 1mM glucose and 0.5mM glutamine as a source of carbohydrate metabolites. After recovery of COCs and in vitro fertilization, a significantly higher number of oocytes developed into blastocysts. The developmental competence of embryos that were originated from ovaries preserved at 15 ℃ was increased compared to those of 25 or 5 ℃. The maturation rate of oocytes was not differed between 24 and 36 h at 15 ℃ but showed lower than control group (71% versus 78%). In vitro-fertilized oocytes from ovaries stored at 25 ℃ for 24 h or at 5 ℃ for 24 h had a significantly decreased developmental potentials, but at 15 ℃ did not (27% versus 29% of blastocysts to develop into day 8). With these results, bovine ovaries can be preserved at 15 ℃ for 36 h without decreasing developmental capacity of in vitro-fertilized oocyte at least to the blastocyst stage. This information provides valuable information of preserving ovaries for embryo transfer or in vitro embryo production.
        4,000원
        86.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Osteochondroma is one of the most common benign tumors of the bone. Although osteochondroma is rarely seen in the facial region, it was reported that the cases occured in the mandibular region, especially around the condyle. Patients complain about malocclusion, temporomandibular disorders and facial asymmetry. The treatments of these cases include total condylectomy or local resection of the lesion. A 48-year-old man visited our hospital. His chief complaints were pain in the left temporomandibular joint (TMJ) and deviation of mandible during mouth opening. Panoramic radiograph showed an enlarged left condyle. A bony proliferation with benign sign was also observed in the computed tomography. Surgical treatment was done by removing the bony mass. Histologically, biopsy result was an osteochondroma. After surgery, there was reduced pain and normal mouth opening. Deviation of the mandible was also observed. We report a case of osteochondroma on the mandibular condyle and a review of literature about the surgical treatment.
        4,000원
        87.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Rail wear in a curved track costs significant amount of maintenance efforts every year. The rail wear is affected by such parameters as train speed, curve radius, and insufficient cant. However, while the effect of train speed and curve radius to the rail wear is relatively well-known, the effect of the insufficient cant has not analytically researched sufficiently. In this paper, the effect of the insufficient cant on rail wear is studied using a multibody dynamics program, the Vi-Rail. The multibody analysis is performed using an EMU train model being operated in the urban railway. The hard track is utilized in the analysis. To identify the relationship between rail wear and insufficient cant. the wear analysis is conducted for various train speeds and curve radius based on the Archard model built in the Vi-Rail program. The analysis result reveals that, as the insufficient cant increases, the vertical and horizontal wear of the outer rail increases, but the wear of the inner rail does not show distinct trend.
        4,000원
        88.
        2016.06 구독 인증기관·개인회원 무료
        국내 고속도로 가속차로에서는 차량이 충분한 가속 후 본선에 합류할 수 있도록 시선유도봉 등의 시설 물을 활용하여 진입차량의 합류를 물리적으로 제한하고 있다. 충분한 가속 후 본선에 진입할 경우 속도 차에 의한 충격파 발생도 억제할 수 있으며 합류구간이 짧은 만큼 상충이 발생하는 구간이 짧아지기 때문 에 가속, 합류구간의 설정은 연결로 운영에 있어 매우 효과적인 운영방안이라고 할 수 있겠다. 그러나 현 재 적정 합류, 가속구간 길이에 대한 연구는 미흡한 실정이며 시선유도봉 설치 시 규정에 의한 설치가 이 루어지지 않고 있다. 따라서 본 연구에서는 미시적 시뮬레이션(VISSIM)을 활용하여 가속차로를 가속구간 과 합류구간으로 분리하는 운영방안을 제시하였으며, 각각의 길이에 따라 연결로 접속부의 소통상태 최적 점을 도출하고자 하였고, 시선유도봉 설치 시 본선과 연결로의 교통수준에 따른 교통특성 변화를 파악하 여 효율적인 고속도로 연결로 운영방안을 제시하고자 하였다. 분석대상구간인 매송IC~안IC 구간은 총 17.5km로 매송IC~비봉IC 구간은 4차로 비봉IC~발안IC 구간 은 3차로로 운영 중이다. 비봉IC 목포방향 연결로 접속부는 본선 3개 차로와 가속차로 1개 차로로 구성되 어 있다. 가속길이가 증가하고 합류길이가 감소함에 따라 본선의 평균통행속도는 지속적인 증가 추세를 나타냈 다. 그러나, 연결로의 경우 합류길이가 감소할 때 150m까지는 통행속도가 증가하였으나, 합류길이가 50m일 때에는 연결로의 통행속도가 46.4km/h까지 급격히 감소하였다. 분석된 시뮬레이션 시공도를 토 대로 각 시나리오별 시간대별 정체길이를 분석한 결과, 정체 시간은 시나리오 3∼5까지 본선이 1시간으로 감소하였으며 시나리오 6에서는 본선의 정체는 해소되나 연결로의 정체시간이 2시간으로 증가하였다. 즉, 본선과 연결로의 소통상태를 고려할 경우, 적정한 가속구간과 합류구간을 구분하는 것이 적절한 것으 로 나타났다.
        93.
        2016.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Infected walled-off pancreatic necrosis (WOPN) is dangerous complication of acute pancreatitis. Open necrosectomy and post-operative irrigation of necrotic cavity have been conventional treatment for infected pancreatic necrosis, however, recently minimally invasive techniques such as endoscopic necrosectomy has been regarded as preferred treatment method for infected WOPN. Endoscopic necrosectomy provides a targeted approach with a reduction in the systemic inflammatory response and avoidance of wound complications. Non alcohol related Wernicke encephalopathy is rare disease caused by thiamine deficiency due to intravenous feeding, and presented an encephalopathy, oculomotor dysfunction, gait ataxia. We report herein a case of Wernicke encephalopathy after successful endoscopic necrosectomy for infected WOPN.
        4,000원
        94.
        2015.11 구독 인증기관 무료, 개인회원 유료
        In this study, we investigated the effects of EGR rate and engine load on the emission characteristics in a 4-cylinder common rail direct injection diesel engine fueled with canola oil biodiesel (BD) blended fuel. The biodiesel blend fuel, BD20 (20 vol.% biodiesel and 80 vol.% ULSD blend) was used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of EGR rate, the combustion pressure and rate of heat release (ROHR) of three test fuels were decreased, and the ignition delay was extended, the carbon monoxide (CO) and particulate matter (PM) emissions increased slightly, but the nitrogen oxide (NOx) emission decreased clearly. On the other hand, with the increasing of engine load, the combustion pressure and ROHR were increased, and the CO and PM emissions decreased. However, the NOx emission was increased due to the rise of the combustion temperature.
        4,000원
        97.
        2015.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Pellicle is defined as a thin transparent film stretched over an aluminum (Al) frame that is glued on one side of a photomask. As semiconductor devices are pursuing higher levels of integration and higher resolution patterns, the cleaning of the Al flame surface is becoming a critical step because the contaminants on the Al flame can cause lithography exposure defects on the wafers. In order to remove these contaminants from the Al frame, a highly concentrated nitric acid (HNO3) solution is used. However, it is difficult to fully remove them, which results in an increase in the Al surface roughness. In this paper, the pellicle frame cleaning is investigated using various cleaning solutions. When the mixture of sulfuric acid (H2SO4), hydrofluoric acid (HF), hydrogen peroxide (H2O2), and deionized water with ultrasonic is used, a high cleaning efficiency is achieved without HNO3. Thus, this cleaning process is suitable for Al frame cleaning and it can also reduce the use of chemicals.
        4,000원
        98.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        개방형 도시정보모델은 3차원 가시성으로 인한 상황 이해도를 증진시키고, 의미정보 및 객체간 관계정보로의 접근으로 인한 효율적인 정보 재사용을 가능하게 하며, 다양한 외부 데이터와의 연계를 통해 구체적이고 신뢰도 높은 의사결정을 지원한다. 본 연구에서는 실제 데이터를 기반으로 지형 및 건물에 대한 개방형 도시정보모델 생성하였다. 또한 침수해 발생과 관련한 수리해석 데이터와 도시정보모델을 연계한 건물의 침수 시뮬레이션 프로세스를 개발하고 이를 적용하였으며, 인명 및 재산피해 예상값을 도출하였다. 마지막으로 정보모델이 포함하고 있는 모델 데이터와 침수 수리해석 결과 및 피해결과를 활용한 구체적인 질의를 통해 도시정보모델의 활용성을 검토하였다.
        4,000원
        99.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study describes the effects of canola oil biodiesel (BD) blended fuel on the combustion performance and emission characteristics in a 4-cylinder common-rail direct injection diesel engine. In this study, with the increasing of engine loads, the biodiesel blend fuels(100 vol.% ULSD and 0 vol.% biodiesel blend, BD0; 80 vol.% ULSD and 20 vol.% biodiesel blend, BD20; 0 vol.% ULSD and 100 vol.% biodiesel blend, BD100; ULSD: ultra low sulfur diesel) were used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of biodiesel blend rate, the combustion pressure decreased slightly at engine load of 20~60Nm. However, the rate of heat release (ROHR) increased clearly and ignition delay time was shortened. With the increasing of biodiesel blend rate, the carbon monoxide (CO) and particulate matter (PM) emissions were more decreased at all of the engine loads.
        4,000원
        100.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate the effect of fuel combustion enhancing apparatus(FCEA) for ionization of intaking air into cylinder combustion chamber on the combustion performance and emissions characteristics in a 4-cylinder common-rail direct injection diesel engine. The experiments were applied to the engine at an engine speed of 1,500rpm under 20Nm, 40Nm, 60Nm and 80Nm conditions. The test results were compared to each other with or without the FCEA. In the case of the FCEA, the combustion pressure, peak combustion pressure and rate of heat release were increased slightly and the brake specific fuel consumption(BSFC) was decreased slightly when compared to that without the FCEA under all loads at an engine speed of 1,500rpm. However, in the case of the FCEA, the nitrogen oxide(NOx) were increased slightly, the carbon monoxide(CO) and particulate matter(PM) were decreased slightly when compared to that without the FCEA under all loads at an engine speed of 1,500rpm.
        4,000원
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