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        검색결과 207

        61.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        First of all, Fe or/and Mn immobilized granular activated carbons (Fe-GAC, Mn-GAC, (Fe, Mn)-GAC) were synthesized and tested to remove arsenate (As(V)). The results in batch test indicated that Fe-GAC removed As(V) effectively, even though the surface area of Fe-GAC was reduced largely. Moreover, adsorption isotherm test indicated that the experimental data fit well with Langmuir model and the maximum adsorption capacity (qmax) of Fe-GAC for As(V) was 3.49 mg g-1, which was higher than GAC (2.24 mg g-1). In column test, the simulated water, which consisted of As(V), Fe(III), Mn(II) and Ca(II) in tap water, was used. Fe-GAC column with 1 hr of pre-washing time treated As(V) effectively while GAC column removed Fe(III) better than Fe-GAC column. Moreover, the increasing pre-washing time from 1 to 9 hour in Fe-GAC column enhanced Fe(III) removal with little negative impact of As(V) removal. Mostly, the column filled with Fe-GAC and GAC (i.e. the mass ratio of Fe-GAC:GAC = 2:8) showed the higher treatability of both As(V) and Fe(III), even it operated with 1 hr pre-washing time.
        4,200원
        62.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The waste casting sands generated from foundry is about 4,000 tons/day and the great part of them is handled by the method of reclamation and just 10% of them is recycled as a sand. This study is to produce the iron lump of high quality material through melting iron particle which is obtained from the waste casting sands. By using the high frequency inductive melting furnace after separating iron particle from casting sand by collision and vibrating classifier, iron lump is produced from melting iron particles. The iron lump of iron content of 96.95% is produced from iron particle of 68.05% through this process. It was investigated that the cost of iron lump is four times higher than the one of iron particle and to produce iron lump is worth to 325 won per kg against iron particle with considering the consumed power(electric energy). Therefore, to produce iron lump from waste casting sands is not only to be economical worth but also to strengthen the ground resources system.
        4,000원
        63.
        2015.11 구독 인증기관·개인회원 무료
        식용수의 비소오염으로 인한 피해로 비소에 대한 관심이 증대되고 있으며, 아시아 지역뿐만 아니라 북남미, 유럽까지 비소로 오염된 지하수가 발견되고 있다. 본 연구에서는 As(Ⅲ)와 As(V)의 흡착특성을 가진 것으로 알려진 망간-철 산화물을 합성하고, PVdF고분자를 이용하여 복합나노섬유를 제조하였으며, 복합막의 물리적 특성과 비소제거 성능을 확인하였다. 복합화 전 합성된 망간-철 산화물을 ICP를 이용하여 비소제거율을 측정한 결과 As(V)는 43.6%, As(Ⅲ)는 65.5%의 제거율을 보였다.
        65.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This Paper deals with the measurement and analysis of the brake squeal noise, the wheel’s and block brake’s vibration. The squeal noise, a kind of self-excited vibration, is generated by the friction between the rim of the revolving wheel and the block brake. Block brake cause friction noise and excessive braking noise makes passengers and operators uncomfortable. The goal of this paper is to investigate experimental the relation between brake squeal noise and behavior of block brake with railway wheel. Experimental results with MA and RMA show that behavior of railway vehicle block brakes is related with brake squeal noise.
        4,000원
        67.
        2015.05 구독 인증기관·개인회원 무료
        Arsenic (As) in drinking water was guided to 10μg/L by World Health Organization (WHO). People living in highly As-contaminated areas can be poisoned by As through inhalation, dermal absorption, and digestion. Many researches and technologies were applied to remove Arsenic in water, such as oxidation, coagulation–precipitation, absorption, ion exchange and membrane techniques. This study aimed to develop microfiltration membranes possessing capability of removing Arsenic. Iron composite Polyvinylidene fluoride (PVDF) membranes were synthesized via phase inversion method for this objective. The As removal of the membranes were investigated by using dead-end filtration system. Membrane properties were characterized by various analytical tools for studying As removal mechanism of these membranes.
        68.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Chinese characters is a letter that is with the most primitive features and is even a dull letter since it took 5000 years to the advent of text hand we are using right now. If we think about Hangul: Korean alphabet which is a scientific letter was made in a generation, dullness of the Chinese characters can even more be highlighted. However, it is this dullness and the honest effectiveness that give the Chinese characters power since it accumulates cultural meanings, especially the meaning of literature, history, and philosophy through concrete shapes and historical precipitations of long time. This study tries to attract the aspects of literature, history, and philosophy inherent in the Chinese characters and to devise a new way to learn Chinese characters that can suggest a humanistic vision. This can simply be summarized as follows. First, the author identified the advantages and disadvantages of existing books with regard to the education of Chinese characters. While books focusing on grades are useful in learning Chinese characters in a short period of time, they can easily neglect the cultural values. On the other hand, while books focusing on cultural aspects let people learn the cultural values based on rich expertise, they are not useful in learning the characters and lack perspective to creatively inherit and develop culture through Chinese characters. Second, the author found out that we need humanistic perspective to avoid disadvantages and encourage advantages. In other words, humanities can converge various cultures focusing on human and can be a foundation to create new culture. And the humanistic elements in the Chinese characters (literature, history, and philosophy) can lead to a more intensified learning. Third, the author investigated principles and ways to draw the elements of literature, history, and philosophy in the characters. Radicals that take the major part of the Chinese characters are like the archetype that determined the language and imagination of people since they are the embodiment of objects closely related to human life. Chinese characters are not only the mean to record history, but also the historical event and fruit encapsulating the perception on the past affairs. Chinese characters show us the world view and the thinking system of ancient people in the East in their composition principles or operational principles. Finally, the author suggested an education method using literature, history, and philosophy focusing on the word '人': human. In a historical perspective, it is highly likely that the word is the embodiment of a person who works while bending his waste forward. And in a literary point of view, there are two poems included as an example that show a deep reflection on human existence. In a philosophical view, the author suggested his view concerning the definition on human. And for the convenience to learn Chinese characters, the author emphasized that the Chinese characters are the essential elements to understand the concepts of Korean by specifying important Chinese characters in the description with regard to literature, history, and philosophy. After that, Chinese characters associated with the word '人' were presented. In conclusion, the purpose of this study that explored ways to configure textbooks for Chinese characters using literature, history, and philosophy is to find out cultural values hidden in Chinese characters and to couple them in to the education of humanities required by the era. While this cannot be a methodology with a clear and specific framework, this can be flexibly used depending on the diversity of majors of teachers and the understanding of learners.
        6,100원
        70.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국지질자원연구원은 몽골 광물자원청과 공동으로 우기누르 철-망간 광화대에 대한 공동 연구를 수행하였다. 이의 일환으로 수행된 육상 자력탐사에서 획득한 자료를 바탕으로 3차원 자력 역산을 수행하였으며, 3차원 지질모델링 기술을 이용하여 철-망간 광화대에 대한 3차원 영상화 및 광체 평가를 위한 연구를 수행하였다. 총자력 이상의 분포 특성을 통해 연구지역의 광상에서 지표 노두로부터 수평적으로 연장되는 광체의 부존 가능성을 확인하였다. 또한, Fe 함량과 상관성이 높은 자기감수율 역산 결과를 토대로 연구지역의 제 1광상 및 제 2광상 모두에서 지표에서 드러난 광체가 지하 하부로 연장되어 있는 것으로 해석되어, 지표에 드러나지 않은 광체의 부존 가능성이 높은 것으로 판단된다. 시추 조사를 통해 일부 대표 지역의 광체 품위 자료가 확보되고 이번 연구결과와의 복합 해석을 수행한다면 효과적인 개발 가능성 평가가 가능할 것으로 판단된다.
        4,000원
        71.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to identify the nutritional risk factors by blood analysis, in 1,083 preschool children of age 3 to 6 years. The frequency of anemic children was 7.3% with Hb<11.1 g/dL, 29.9% with ferritin<20 ng/mL, and 16.7% with transferrin Fe saturation(%)<15%. The prevalence of anemia in these children were 12.8% for those with MCV<79 fL, and it was 71% for those with TIBC>400 μg/dL. Serum ferritin concentration was 20 ng/mL in the normal children. Thirty two percent of the children had anemia with Hb<12 g/dL, which is below the normal range of Hb. Exactly 15.4% of the children had serum Fe concentration of 60 μg/dL. The transferrin Fe saturation of the children (16.3%) was >15%. The serum ferritin concentration showed low correlations with Hb, Fe, transferrin Fe saturation, and MCV. The transferrin Fe saturation, higher Hb concentration, MCV, and Hct values were increased significantly. Consequently, iron-deficiency anaemia was thus defined as having Hb concentration <12 g/dL accompanied by ferritin concentration <20 ng/mL or Hct <33%.
        4,000원
        72.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 모형실험을 통하여 다짐도 및 매입깊이에 따른 나선철항의 인발저항력을 검토하였다. 그 결과 다짐도 및 매입깊이가 증가할수록 인발저항력은 증가하는 것으로 나타났으며, 특히 다짐률 85%의 지반조건에서 인발저항력은 매입깊이 25cm, 30cm, 35cm 및 40cm 별로 각각 48.9kgf, 57.9kgf, 86.2kgf 및 116.6kgf로 다른 지반조건일 때 보다 현저하게 높은 인발저항력이 나타났다. 그리고 다짐률에 따른 인발저항력은 각 매입깊이 조건별(30cm, 35cm 및 40cm)로 다짐률 75% 및 85%에서 급격하게 증가하는 유사한 경향이 나타났다. 나선철항의 인발저항력은 지반의 다짐률에 따라 상당한 차이를 보였으며 극한인발저항력의 최대값은 다짐률 85%의 지반조건 및 매입깊이 40cm에서 116.6kgf로 나타났다. 이는 나선철항의 제원을 고려해볼 때 매우 높은 것으로 판단된다. 따라서 평소 나선철항 주변 지반의 유지관리를 철저히 한다면 바람에 대한 피해를 효과적으로 경감시켜 줄 수 있을 것으로 판단된다. 그리고 나선 철항은 플라스틱 필름을 고정하는 용도뿐만 아니라 온실 형태별로 개수 및 간격 등 적절한 설치방법이 제시된다면 온실의 구조적 안정성에도 기여를 할 수 있을 것으 로 예상된다. 또한 본 연구의 결과를 검토해 볼 때 온실에 나선설항의 설치시 유용한 효과를 기대하기 위해서는 매입깊이 35cm 이상 그리고 다짐률은 85%이상을 적용해야 할 것 으로 판단되며, 본 실험에서 다짐률 85%에 해당하는 모형지반의 상대밀도는 67%정도 였다.
        4,000원
        73.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the artistic column used by Glass Fiber Reinforced Plastic(GFRP), the connection of steel with GFRP were needed. Due to the fabricating characteristics of hand laminating, GFRP surfaces had to be connected. Because there were no existed data of these connection, experimental study has to be followed so that the structural strength and buckling mode could be investigated. In this paper, therefore, the axial tests of steel with GFRP were performed. The connection of GFRP's surfaces could be also tested as well. As a result, it could be figured out that the strength of these connections were determined by the adhesive strength.
        4,000원
        74.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Stress-strain curves are fundamental properties to study characteristics of materials. Flow stress curves of the powder materials are obtained by indirect testing methods, such as tensile test with the bulk materials and powder compaction test, because it is hard to measure the stress-strain curves of the powder materials using conventional uniax- ial tensile test due to the limitation of the size and shape of the specimen. Instrumented nanoindentation can measure mechanical properties of very small region from several nanometers to several micrometers, so nanoindentation tech- nique is suitable to obtain the stress-strain curve of the powder materials. In this study, a novel technique to obtain the stress-strain curves using the combination of instrumented nanoindentation and finite element method was introduced and the flow stress curves of Fe powder were measured. Then obtained stress-strain curves were verified by the com- parison of the experimental results and the FEA results for powder compaction test.
        4,000원
        75.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As far as recent investment in railway, disused railway yards is increased in each line and region. As a result, the interest of the related local government and agencies has increased on utilizing disused railway yards. In this study, we investigated the status of the disused railway yards and conducted legal review on the use of disused railway yards. In addition, we analyzed the disused railway yards use practices through case analysis and also suggested plans to diversify the ways of their usage.
        4,200원
        76.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetic and dielectric properties of rubber composites are controlled by using two kinds of high-permeability metal particles with different electrical conductivity (Sendust, Permalloy), and their effect on microwave absorbance has been investigated, focusing on the quasi-microwave frequency band (0.8-2 GHz). Noise absorbing sheets are composite materials of magnetic flake particles of high aspect ratio dispersed in polymer matrix with various filler amount of 80-90 wt.%. The frequency dispersion and magnitude of complex permeability is almost the same for Sendust and Permalloy composite specimens. However, the complex permittivity of the Permalloy composite (, ) is much greater than that of Sendust composite (, ). Due to the large dielectric permittivity of Permalloy composite, the absorbing band is shifted to lower frequency region. However, the investigation of impedance matching reveals that the magnetic permeability is still small to satisfy the zero-reflected condition at the quasi-microwave frequency band, resulting in a small microwave absorbance lower than 10 dB.
        3,000원
        77.
        2013.04 구독 인증기관 무료, 개인회원 유료
        As far as recent investment in railway, disused railway yards is increased in each line and region. As a result, related local government and agencies has been increased interest for utilization of disused railway yard. In this study, we investigated the status of the disused railway yards and conducted legal review on the use of disused railway yards. In addition, we analyze the disused railway yards use practices through case analysis and suggest plans to diversify ways to use.
        4,800원
        79.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        무기안료는 인체에 대한 안정성과 다른 소재와의 상용성이 우수하며, 미적 특성을 감미하기 위한 화장품, 인쇄잉크, 페인트, 건설자재 등 다양한 분야에서 관심 받고 있다. 본 논문에서는 망간과 철이 도핑된 이산화티탄 안료를 합성하기 위하여 수열합성법을 이용하였다. 공정 변수로는 망간 전구체의 양, 철 전구체의 양 및 하소온도 등을 변화시켰다. 제조된 안료의 최적 조건은 망간 전구체의 양이 1.0wt%, 철 전구체의 양이 1.5wt% 그리고 하소온도 550℃일 때였다. 제조된 안료는 XRD, EDS, FE-SEM, Spectrophotometer, UV-Vis Spectrometer 등으로 분석 하였다.
        4,000원
        80.
        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
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