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        검색결과 208

        81.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper to prevent human errors analyzed the causes of railway accidents and human error in last 5 years(2007~2011). The 2nd Railway Comprehensive Safety Plan currently being implemented in the safety business for prevention of human error. The accidents are often resulted from multiple causes with hardware failure and human errors. And prevention of human error associated with the implementation details of the priority projects, 14 projects were selected by draw. Then Analytic Hierarchy Process(AHP) methodology was used to select what projects were effective to human error.
        4,000원
        82.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The overall goal of a safety based railroad system is either to eliminate hazards in designing or to minimize the possibility of it. In order to indicate system safety or low risk although it may not be possible to achieve zero risk conditions, first, it shall ensure that any disasters would occur due to system operation because the prescribed specifications are properly fulfilled and there are no failures of any kind. Second, the risk of faults or failures leading to a mishap must be eliminated or minimized by using fault-tolerance or fail-safe procedures. This paper will attempt to summarize the personal and social risk criterion at widely scattered points, presently used as a safety approach in all over EU, in order to establish the step by step procedures of the detailed standard for railway facilities. In addition, we present the new safety analysis method using the SIL-based evaluation standard and the Reachability Graph of the Petri Net.
        4,000원
        83.
        2011.09 구독 인증기관 무료, 개인회원 유료
        4,000원
        85.
        2011.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of ferrous/ferric molar ratio on the formation of nano-sized magnetite particles was investigated by a co-precipitation method. Ferrous sulfate and ferric sulfate were used as iron sources and sodium hydroxide was used as a precipitant. In this experiment, the variables were the ferrous/ferric molar ratio (1.0, 1.25, 2.5 and 5.0) and the equivalent ratio (0.10, 0.25, 0.50, 0.75, 1.0, 2.0 and 3.0), while the reaction temperature (25˚C) and reaction time (30 min.) were fixed. Argon gas was flowed during the reactions to prevent the Fe2+ from oxidizing in the air. Single-phase magnetite was synthesized when the equivalent ratio was above 2.0 with the ferrous/ferric molar ratios. However, goethite and magnetite were synthesized when the equivalent ratio was 1.0. The crystallinity of magnetite increased as the equivalent ratio increased up to 3.0. The crystallite size (5.6 to 11.6 nm), median particle size (15.4 to 19.5 nm), and saturation magnetization (43 to 71 emu.g-1) changed depending on the ferrous/ferric molar ratio. The highest saturation magnetization (71 emu.g-1) was obtained when the equivalent ratio was 3.0 and the ferrous/ferric molar ratio was 2.5.
        4,000원
        86.
        2011.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study aimed to verify the effects of DFO on PDL cells, with particular emphasis on focusing on osteoblastic differentiation. Its mechanisms related to heme oxygenase-1 (HO-1) pathway were also analyzed. DFO increased the expression of HO-1 and early osteoblastic differentiation markers, such as alkaline phosphatase (ALP) and bone sialoprotein (BSP). DFO upregulated heme oxygenase-1. Treatment with HO-1 siRNA blocked the DFO-stimulated osteoblastic differentiation and HO-1 expression. The NF-kB inhibitor pyrrolidine dithiocarbamate, phosphatidylinositol 3-kinase inhibitor Wortmannin, and p38 MAPK inhibitor U0126 blocked the effects of DFO on HO-1 expression and osteoblastic differentiation in PDL cells. Collectively, these data suggest that DFO promotes osteoblastic differentiation and induces the expression of defense protein HO-1 probably via PI3K, p38 MAPK, and NF-kB signalling pathways in PDL cells.
        4,000원
        92.
        2010.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The chemical formula of magnetite (Fe3O4) is FeO·Fe2O3, t magnetite being composed of divalent ferrous ion andtrivalent ferric ion. In this study, the influence of the coexistence of ferrous and ferric ion on the formation of iron oxide wasinvestigated. The effect of the co-precipitation parameters (equivalent ratio and reaction temperature) on the formation of ironoxide was investigated using ferric sulfate, ferrous sulfate and ammonia. The equivalent ratio was varied from 0.1 to 3.0 andthe reaction temperature was varied from 25 to 75. The concentration of the three starting solutions was 0.01mole. Jarosite wasformed when equivalent ratios were 0.1-0.25 and jarosite, goethite, magnetite were formed when equivalent ratios were 0.25-0.6. Single-phase magnetite was formed when the equivalent ratio was above 0.65. The crystallite size and median particle sizeof the magnetite decreased when the equivalent ratio was increased from 0.65 to 3.0. However, the crystallite size and medianparticle size of the magnetite increased when the reaction temperature was increased from 25oC to 75oC. When ferric and ferroussulfates were used together, the synthetic conditions to get single phase magnetite became simpler than when ferrous sulfatewas used alone because of the co-existence of Fe2+ and Fe3+ in the solution.
        4,000원
        93.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Iron(Fe)-Molybdenum(Mo) alloyed nanoparticles and nanowires were produced by the chemical vapor condensation(CVC) process using the pyrolysis of iron pentacarbonyl() and Molybdenum hexacarbonyl(). The influence of CVC parameter on the formation of nanoparticle, nanowire and size control was studied. The size of Fe-Mo alloyed nanoparticles can be controlled by quantity of gas flow. Also, Fe-Mo alloyed nanowires were produced by control of the work chamber pressure. Moreover, we investigated close correlation of size and morphology of Fe-Mo nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. Obtained nanoparticles and nanowires were investigated by field emission scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction.
        4,000원
        94.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The types and quantities of Hazmat and Hazmat transportation are gradually increasing, keeping pace with industrialization and urbanization. At present the safety management for Hazmat transportation only considers reducing accident probability, but even when an accident involving Hazmat-carrying vehicles occurs, that is not regarded as a Hazmat-related accident if the Hazmats do not leak out from the containers carrying them. Thus the methods to reduce risk (Risk=Probability×Consequence) have to be developed by incorporating accident probability and consequence. By using Geographic Information System (GIS), a technical method is invented and is automatically able to evaluate the consequence by different types of Hazmat. Thus this study analyzed the degree of risk on the links classified by the Hazmat transport pathways. In order to mitigate the degree of risk, a method of 7-step risk management on Hazmat transportation in railway industries can be suggested. (1st step: building up GIS DB, 2nd step: calculating accident probability on each link, 3rd step: calculating consequence by Hazmat types, 4th step: determination of risk, 5th step: analysis of alternative plans for mitigating the risk, 6th: measure of effectiveness against each alternative, and 7th step: action plans to be weak probability and consequence by the range recommended from ALARP). In conclusion, those 7 steps are used as a standardization method of optimum transportation routing. And to increase the efficiency of optimum transportation routing, optional route can be revise by verification.
        4,200원
        95.
        2009.11 구독 인증기관 무료, 개인회원 유료
        railroad has a benefit of the mass transportation of a passenger and cargo, but just a time of accident could cause a huge loss of a human life and property. Especially, a typhoon and a localized torrential downpour usually happened in summer season have caused average 38.29 times of the missing roadbed which support the railroad in recent 7 years. If a train would pass on this railroad which the roadbed was missed, there could be a huge accident and many people will die. But, the security issue is not satisfied because the method of sensing the missing roadbed is depending solely on the naked eye inspection by a person in charge. So, in this study, I would like to suggest the missing roadbed real-time sensing and train operation system to reduce the possibility of the railroad accident by controlling the operation of train when the missing roadbed condition would be sensed in the real-time system.
        4,000원
        96.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 공업용수 중에 미량 함유될 수 있는 철 이온 제거를 위해 철 용액에 음이온 계면활성제 SDS를 주입하여 미셀을 형성한 후, 미셀 표면에 철 이온의 흡착 또는 결합으로 형성된 응집체를 관형 세라믹 정밀여과막으로 제거하였다. 음이온 계면활성제의 영향을 살펴보기 위해 일정한 1mM의 철 농도에서 음이온 계면활성제의 농도를 0~10 mM로 변화시켰다. 그 결과, 6mM 일 때 가장 높은 철 제거율 88.97%를 보였다. SDS 농도에 따른 미셀 응집체의 입도 분포를 확인하기 위해 전기영동광산란분광광도계(Electrophoretic Light Scattering Spectrometer)를 사용하여 분석 한 결과, 6mM 일때 큰 응집체의 분포도가 가장 높았다. 또한, 세라믹 분리막에 대하여 주기적 질소 역세척을 실시할 경우 역세척 주기의 영향을 조사하였다. 그 결과, NCMT-7231 (평균기공 0.10μm) 분리막의 최적 역세척 시간(BT)는 20초이었다.
        4,000원
        97.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Railroad Safety Act was implemented in 2005 due to the increased concerns regarding railroad safety since the Daegu subway fire in 2003. In line with this, the Act became a standard to build the total railroad safety systems which has been overlooked compared to the quantitative growth of the railroad business. The minister of the ministry of Land, Transportation and Maritime Affairs lays down the Act for railroad Companies to conduct emergency programs in response to the emergency occurring on the railroad such as fire, explosion, derailment, etc. By enacting the Safety Act, the nation's construction of the contingency management system for railroad emergency increased", and it made the railroad company prepare the Emergency SOP by establishing 'The guideline on the Establishment of the railroad Emergency Plan' in order to support the efficiency of the Act. In line with this, I would like to analyze a matter of system development and the main function of the "railroad Emergency Training Program" for activation improvement of standardized operation procedure developed through the 'Total capitalize Safety Technology development'.
        4,000원
        98.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Considering the great potential of iron chelators at inhibiting the proliferation of tumor cells, in order to determine the molecular and biological basis for the effects of iron chelator in oral cancer, we investigated the effects of iron chelator, desferrioxamine (DFO), on the gene profiling analysis of immortalized human oral keratinocytes (IHOK), and oral cancer cells (HN12), using the cDNA microarray. We identified 46 clones cDNA exhibiting more than 2 fold overexpression in DFO treated IHOK and HN12 cells, and 94 cDNA reveal more than 2 fold down-regulated expression. Examination of gene expression that differs between DFO treated vs. control IHOK and HN12 cells apprear to be related to : cell cycle regulator, cell growth and apoptosis, signal transduction and stress. p21 for cell cell cycle factor was upregualted, and cyclin-cdk gene was decreased expression, so we observed cell cycle arrest in DFO treated IHOK and HN12 cells. In tumor growth, we have identified downregulation of hemidesmosomal protein (bullous pemphigoid antigen 1) and epiregulin expression in DFO treated IHOK and oral cancer cells. Signal transducers including mitogen-activated protein kinase-activated protein kinase 5, serine/thereonine kinase 6 were downregulated with DFO treated cells, suggesting the DFO regulates the p38 MAP kianse pathway in immortalized and maignant oral keratincytes. In conclusion, we have demonstrated the high-throughput utility of cDNA array hybridization in parallel to the gene expression analysis to identify genes that are expressed differentially in DFO treated with immortalized and malignant oral keratinocytes. The differentially expressed genes identified here should be informative in DFO-induced anti-cancer effects.
        4,300원
        99.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        潘悟云(2002)는 중국어 오방언의 인칭 대명사 복수 부가성분인 t/d、l와 n은 方位名词 “耷”에서 유래했다고 주장한다. 본문은 이 주장이 적절하지 못하다고 여긴다. 본문은 충분한 자료를 바탕으로 이러한 접미사가 중국어와 티베트버마어, 알타이어계에 속하는 각 언어들에서 광범위하게 분포하고 있음을 증명한다. 이것에 근거하여 중국어-티베트버마어와 알타이어의 인칭대명사 복수 접미사는 동일성을 가지고 있으며, 그 출현 시기도 매우 빨라 동북아시아 지역의 원시 언어의 공통적인 부분이라는 가설을 제시한다. 이런 종류의 동일성이 과연 발생학적인 측면의 성질인지 아니면 교류로 인한 조성 인지는 지금 성급히 결론을 내릴 필요는 없다. 본문은 유전학적 연구 성과를 인용하여 이러한 가설을 지지하고자 한다.
        5,400원
        100.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Biological organisms require iron for optimal metabolism. Intracellular pathogens also must secure iron especially during infection of animal hosts expressing NRAMP(natural resistance-associated macrophage protein), a transporter protein sequestering metal ions from pathogens. This study shows that extracytoplasmic function sigma factor σE is required for Salmonella virulence in NRAMP1-expressing mice, and further shows that iron deprivation turns on σE expression of Salmonella. The virulence of σE -deficient Salmonella is completely attenuated in C3H/HeN mice while wild type Salmonella kills all mice. Addition of an iron-chelator DTPA(Diethylene triamine pentaacetic acid) to culture media induces σE expression of Salmonella, but iron supplementation abrogates this induction. These findings suggest that iron limitation in host macrophages can trigger σE -dependent virulence system of Salmonella that may include bacterial iron homeostasis.
        3,000원
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