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        검색결과 300

        81.
        2016.08 구독 인증기관 무료, 개인회원 유료
        이 글은 지금까지 축적된 삼척지역의 대표적인 철기시대 유적·유물과 묘제[무 덤]을 정리·분석하여 이 지역의 철기시대 문화양상을 파악하고, 문헌자료를 함께 검토하여 삼국시대 이전에 삼척을 중심으로 형성·발전해 나갔던 실직국의 역사적 실체를 규명함에 그 목적을 두었다. 삼척지역의 철기시대 문화양상은 ‘중도유형문화’로 인식되고 있는 예[동예]의 문 화양상과 대동소이한 것으로 파악된다. 삼척지역 내 철기시대 주거지는 해안사구 지대에 집중적으로 입지하며, 凸자형·呂자형·(장)방형의 평면형태를 띠고 있다. 주거지 내부에서는 다양한 노(爐), 바닥 점토다짐, 벽체마감시설 등과 화재로 인해 폐기된 집자리가 다수 확인된다. 주거지 유적 내에서는 중도식토기[경질무문토기·타날문토기]와 함께 외래계토 기[영남계·낙랑계토기]와 이를 모방한 새로운 토기양상도 확인된다. 그리고 진· 변한지역에서 유입된 것으로 추정되는 다량의 옥장신구와 청동세환[소환] 등이 출토된다. 이러한 문화적 양상을 볼 때, 삼척의 철기시대 문화는 주변지역의 정치세력과 적극적으로 교섭하면서 선진문화를 수용하고 재지문화를 발전시켜 나간 것 으로 보인다. 한편 삼척지역을 포함한 강원 영동지역 내에서는 철기시대 묘제가 전혀 확인되지 않는다. 이러한 양상은 실직국이 삼한의 정치체와는 달리 옥저의 지상식 목곽 묘의 장례문화를 공유하여 지상에 무덤을 만들었기 때문에 오늘날 그 흔적이 남아있지 못한 것으로 이해된다. 『삼국사기』와 삼척지역 내 주거지와 신라고분을 살펴본 결과, 삼척의 철기시대 문화와 실직국은 신라가 동해안지역으로 진출하는 과정에서 5세기를 전후하여 신라의 영역으로 편입되면서 점차 해체되어 간 것으로 보인다. 삼척의 철기시대 문화는 신라화 과정 속에서 해체되어 갔지만, 고고학적으로 영동지역 최대의 마을유적인 동해 송정동유적에서 다양한 외래계유물과 철기생산과 관련된 단야공방지가 다수 확인되는 점, 이후 실직주가 설치되어 군사적 전략기지 [수군기지]의 역할을 담당한 점 등을 미루어 볼 때, 그 역사·문화적 위상은 높게 평가된다.
        10,500원
        82.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbonyl iron (CI) is successfully incorporated as an additive into a polystyrene (PS) matrix via a highenergy ball milling method, under an n-hexane medium with volume fractions between 1% and 5% for electromagnetic interference shielding applications by the combination of magnetic CI and an insulating PS matrix. The morphology and the dispersion of CI are investigated by field emission scanning electron microscopy, which indicates a uniform distribution of CI in the PS matrix after 2 h of milling. The thermal behavior results indicate no significant degradation of the PS when there is a slight increase in the onset temperature with the addition of CI powder, when compared to the as-received PS pellet. After milling, there are no interactions between the CI and the PS matrix, as confirmed by Fourier transformed infrared spectroscopy. In this study, the milled CI-PS powder is extruded to make filaments, and can have potential applications in the 3-D printing industry.
        4,000원
        83.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 비소(arsenic, As) 제거 특성을 가진 망간-철 산화물(manganese-iron oxide, MF)을 제조하고, 이를 poly vinylidene fluoride (PVdF)와 복합화를 진행하여 As(III)와 As(V)를 동시에 제거가 가능한 수처리용 나노섬유복합막 (polymer nanofiber membrane with Mn-Fe, PMF) 제조에 관한 기초 연구를 진행하였다. Transmission electron microscope (TEM) 분석을 통해 MF 소재의 형상 및 구조를 확인하였으며, PMF 복합막의 수처리용 분리막으로의 활용가능성을 조사하 기 위하여 기계적 강도, 기공크기, 접촉각 및 수투과도 분석을 진행하였다. 측정결과로부터 망간과 철 비율이 같은 PMF11 복 합막의 기계적 강도가 가장 높은 결과값(232.7 kgf/cm2)을 나타낸 것을 확인할 수 있었다. 또한, MF 소재의 도입에 따라 기공 크기가 점차 줄어드는 경향성을 확인할 수 있었으며, 특히, 철 산화물의 조성비가 증가할수록 기공크기가 감소하는 경향성을 보여주었다. 수투과도 측정결과 MF 소재의 도입에 따라 PVdF 나노섬유막에 비해 약 10~60% 이상 향상되는 결과를 나타내 었다. 제조된 MF 소재 및 PMF 복합막의 비소 제거 특성평가를 통해 As(III)와 (V)의 동시 제거 가능하며, 특히, MF01 샘플 의 경우 As(III)와 (V)에 각각 93, 68%의 가장 높은 흡착제거율을 나타내었다. 따라서 본 연구에서는 제조된 MF소재 및 PMF 복합막을 통해 수처리용 분리막의 기능성 향상을 위한 기초연구 자료로 활용할 수 있을 것으로 기대된다.
        4,000원
        84.
        2016.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fabrication of iron oxide/carbon nanotube composite structures for detection of ammonia gas at room temperature is reported. The iron oxide/carbon nanotube composite structures are fabricated by in situ co-arc-discharge method using a graphite source with varying numbers of iron wires inserted. The composite structures reveal higher response signals at room temperature than at high temperatures. As the number of iron wires inserted increased, the volume of carbon nanotubes and iron nanoparticles produced increased. The oxidation condition of the composite structures varied the carbon nanotube/iron oxide ratio in the structure and, consequently, the resistance of the structures and, finally, the ammonia gas sensing performance. The highest sensor performance was realized with 500 oC/2 h oxidation heat-treatment condition, in which most of the carbon nanotubes were removed from the composite and iron oxide played the main role of ammonia sensing. The response signal level was 62% at room temperature. We also found that UV irradiation enhances the sensing response with reduced recovery time.
        4,000원
        85.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out for characterization of MIO synthesized in our laboratory by co-precipitation method and applied isotherm and kinetic models for adsorption properties. XRD analysis were conducted to find crystal structure of synthesized MIO. Further SEM and XPS analysis was performed before and after phosphate adsorption, and BET analysis for surface characterization. Phosphate stock solution was prepared by KH2PO4 for characterization of phosphate adsorption, and batch experiment was conducted using 50 ml conical tube. Langmuir and Freundlich models were applied based on adsorption equilibrium test of MIO by initial phosphate solution. Pseudo first order and pseudo second order models were applied for interpretation of kinetic model by temperature. Surface area and pore size of MIO were found 89.6 m2/g and 16 nm respectively. And, the determination coefficient (R2) value of Langmuir model was 0.9779, which was comparatively higher than that of Freundlich isotherm model 0.9340.
        4,000원
        86.
        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
        87.
        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.
        88.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The functional wood plastic composite(WPC) is one of the noted materials for landscape architecture and residential construction. Iron band, embossing and drain holes are improve the strength and skid resistance of the WPC. In this study, we had developed an automatic manufacturing system for the functional WPC that has vertical pattern embossing and drain holes. The system is consist of an automatic vertical pattern embossing device, multi-spindle drilling M/C, sanding device, inspection equipment, and some facilities developed in the previous research. The performance tests on the several functional items of the system and manufactured WPC represented satisfactory values except the skid resistance and absorption thickness expansion rate.
        4,000원
        89.
        2015.05 구독 인증기관·개인회원 무료
        Excess phosphorus in water has become a crucial aspect concerning the eutrophication. Experiments were carried out to fabricate particles of iron oxide to polymer and the beads were then calcinated. It was found that adsorption process most satisfactory fitted to Langmuir equation (R2>0.92) with maximum adsorption capacity 2.663 mg P/g adsorbent. Equilibrium of adsorption was reached after 3 h, while the initial adsorption rate increased from 0.46 mg/g-h to 3.83 mg/g-h when the bead iron content increased from 40.4 mg Fe/g to 160 mg Fe/g. This research was supported by a project (No. 2013001390002) from the Korea Environmental Industry & Technology Institute funded by the Ministry of Environment and the Brain Korea 21 Plus program of the Korean government.
        90.
        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.
        91.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we have developed an automatic manufacturing system for functional wood plastic composites(WPC) which are one of spotlighting materials for landscape architecture and residential construction material. In addition to the existing facilities, this manufacturing system is consist of an automatic hole manufacturing device, iron band supply and winding device, mold with the iron band insert system, calibration unit, control system, etc. We have performed the performance tests for the system such as the specific gravity, bending strength, screw holding power, percentage of moisture content, formaldehyde, absorption thickness, expansion rate, cold resistance(appearance & bending strength), and shock resistance. As a result, the performance of the prototype system satisfies all the objects of this study.
        4,000원
        92.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the reduction kinetics and behaviors of oxides in the water-atomized iron powder have been evaluated as a function of temperature ranging 850-1000˚C in hydrogen environment, and compared to the reduction behaviors of individual iron oxides including Fe2O3, Fe3O4 and FeO. The water-atomized iron powder contained a significant amount of iron oxides, mainly Fe3O4 and FeO, which were formed as a partially-continuous surface layer and an inner inclusion. During hydrogen reduction, a significant weight loss in the iron powder occurred in the initial stage of 10 min by the reduction of surface oxides, and then further reduction underwent slowly with increasing time. A higher temperature in the hydrogen reduction promoted a high purity of iron powder, but no significant change in the reduction occurred above 950˚C. Sequence reduction process by an alternating environment of hydrogen and inert gases effectively removed the oxide scale in the iron powder, which lowered reduction temperature and/or shortened reduction time.
        4,000원
        95.
        2014.09 구독 인증기관 무료, 개인회원 유료
        To investigate the association between maternal iron status at the third trimester and fetal birthweight, maternal serum iron, ferritin, total iron-binding capacity (TIBC), and complete blood count values were measured at 36-weeks gestation. Delivery database on mothers who delivered babies at Chungbuk National University Hospital between January 2008 and March 2013 was extracted. A total of 353 uncomplicated term babies were analyzed using hierarchical regression and ANCOVA. Maternal age (standardized regression coefficient β=0.115, P<0.05), height (β=0.108, P<0.05), BMI (β=0.210, P<0.001), and gestational age (β=0.298, P<0.001) were significantly associated with birthweight. However, birthweight was not associated with maternal iron parameters. After adjusting for maternal age, height, BMI, and gestational age, babies born to mothers with lower mean values of hemoglobin, hematocrit, and serum ferritin were heavier than those born to mothers with higher values. Babies born to lower hemoglobin (11 g/dL) mothers were heavier than those born to higher hemoglobin (12 g/dL) mothers. However, birthweight was not significantly different between mothers with 10 g/dL or 13 g/dL of hemoglobin. Comparing birthweight according to 30 ug/dL of serum iron, 360 ug/dL of TIBC, 15 ng/mL of serum ferritin, and 10% transferrin saturation, babies born to mothers of the lower group were heavier than those born to mothers of the higher group. Therefore, maternal serum iron status at the third trimester seems to not be associated with birthweight.
        4,000원
        96.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research developed ultra-pressure pump main body by using ductile cast iron FCD500, conducted quantitative analysis on following phenomenon of flow or solidification processing in cast processing for improvement of cast device, after extracting model from cast concluded as follows by brinel hardness test. after selecting the ideal condition of cast and it applied to cast of real product shape, discovered the ideal filling processing under the condition that temperature of molten metal was between 1300℃ and 1280℃. and after finishing filling, solidification was commenced rapidly when percentage of solidification completion was between 40%~50%, at that moment, the termperature was measured 1100℃. moreover under the condition of temperature below 900℃, keeping temperature on the center of parts for a certain period of time brings stability of stabilization of heat in parts and organizational stabilization of ductile cast iron. As the results of the casting method design, it was that the ductile cast parts of pump main body was obtained as the maximum HB of 220 was recorded and good test results were achieved
        4,000원
        97.
        2014.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This is the study on diffusion of ceramic body oxide compounds to glaze. For ceramic bodies, no ferrous oxides contain white ware, celadon, and 3 wt% iron oxides contained white ware was used in this experiment. These ceramic bodies were glazed by transparency glaze, iron oxides contained glaze, and glaze made by pine tree ash that treated in 1240 degree, under reduction condition for an hour. An electron probe microanalyzer(EPMA) was used to study diffusion of oxides and to calculate distance of ceramics bodies. As a result, only iron oxide and magnesium oxide from the body diffused to glaze, and also made a band which shown very thin layer of iron oxide and magnesium oxide between the body and glaze. The densest band of iron oxide formed 100 to 150μm in the glaze, and the densest band of magnesium oxide was found 50 to 100μm in the glaze. Therefore, it could be concluded that iron oxide in the body is diffused to the glaze and it affects the color of glaze, even though iron oxide exists in the glaze. Furthermore, the thickness of the glaze has an effect on the color of celadon.
        4,000원
        98.
        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
        100.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Indoor air quality including metro subway is of recent interests in large cities. Inflow air to the inside of the train and circulating air flow through MVAC of stations contain large amount of iron based fine particles. This paper evaluated the collection of such a dust by magnetic filters as comparing to conventional particle capturing mechanisms such as inertia, direct impaction and diffusion. It was found that filtration velocity, magnetic field intensity, and fiber size were the most important parameters for magnetic filtration. Application of magnetic force obviously enhances the collection efficiency particularly in fine modes smaller than 10 mm. However, its effect was found greater in 2.5 mm than submicron particles.
        4,000원
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