• 제목/요약/키워드: e-AG

검색결과 645건 처리시간 0.026초

콘크리트의 염화물이온 확산성상에 미치는 온도의 영향 (Influence of Temperature on Chloride Ion Diffusion of Concrete)

  • 소형석;최승훈;서중석;서기석;소승영
    • 콘크리트학회논문집
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    • 제26권1호
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    • pp.71-78
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    • 2014
  • 사용후핵연료의 중간저장시설인 콘크리트 캐스크(cask)는 해안부근에 입지할 가능성이 크기 때문에 염해에 대한 문제가 크게 우려된다. 그리고 염해에 의한 철근의 부식 및 균열발생은 철근콘크리트구조물의 방사선 차폐기능뿐 아니라 구조성능 저하의 주요 원인이기 때문에 염해에 대한 평가는 매우 중요한 사항이다. 특히 염해환경과 함께 콘크리트 캐스크 내부에서는 사용후핵연료의 발열에 의해 $60^{\circ}C$정도의 고온 환경이 예상되기 때문에 고온에서의 염해에 대한 검토가 요구되지만, 기존 콘크리트 구조물의 염해평가에서는 온도에 대한 영향이 전혀 고려되어 있지 않아 고온에서 염해에 노출된 철근콘크리트구조물들의 내구설계 및 수명예측을 위해 참고할 만한 자료가 거의 없다. 이 연구에서는 다양한 온도환경에서의 염수(NaCl)침지시험을 통해 콘크리트의 염화물이온 확산계수를 측정하고 염화물이온 확산계수와 온도의 관계를 규명하고자 하였다. 실험 결과, 콘크리트의 염화물이온 확산계수는 온도의 증가에 따라 현저히 증대하여 고온환경에서의 염해 발생가능성이 매우 큰 것으로 조사되었다. 또한 크리트의 염화물이온 확산계수는 물시멘트(W/C)비가 낮아질수록 감소하였고, 이 경향은 온도가 증가(고온환경)하여도 동일하게 나타났다. 염화물이온 확산계수의 온도의존성은 아레니우스식(Arrhenius equation)으로 나타내어졌고 회귀분석 결과, 확산계수의 대수 값은 절대온도의 역수와 선형관계를 나타내었다. 또한 온도의존성을 나타내는 활성화에너지(activation energy)는 물시멘트(W/C)비가 낮을수록 높게 나타났다.

Non-gaseous Plasma Immersion Ion Implantation and Its Applications

  • Han, Seung-Hee;Kim, En-Kyeom;Park, Won-Woong;Moon, Sun-Woo;Kim, Kyung-Hun;Kim, Sung-Min
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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    • pp.151-151
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    • 2012
  • A new plasma process, i.e., the combination of PIII&D and HIPIMS, was developed to implant non-gaseous ions into materials surface. HIPIMS is a special mode of operation of pulsed-DC magnetron sputtering, in which high pulsed DC power exceeding ~1 kW/$cm^2$ of its peak power density is applied to the magnetron sputtering target while the average power density remains manageable to the cooling capacity of the equipment by using a very small duty ratio of operation. Due to the high peak power density applied to the sputtering target, a large fraction of sputtered atoms is ionized. If the negative high voltage pulse applied to the sample stage in PIII&D system is synchronized with the pulsed plasma of sputtered target material by HIPIMS operation, the implantation of non-gaseous ions can be successfully accomplished. The new process has great advantage that thin film deposition and non-gaseous ion implantation along with in-situ film modification can be achieved in a single plasma chamber. Even broader application areas of PIII&D technology are believed to be envisaged by this newly developed process. In one application of non-gaseous plasma immersion ion implantation, Ge ions were implanted into SiO2 thin film at 60 keV to form Ge quantum dots embedded in SiO2 dielectric material. The crystalline Ge quantum dots were shown to be 5~10 nm in size and well dispersed in SiO2 matrix. In another application, Ag ions were implanted into SS-304 substrate to endow the anti-microbial property of the surface. Yet another bio-application was Mg ion implantation into Ti to improve its osteointegration property for bone implants. Catalyst is another promising application field of nongaseous plasma immersion ion implantation because ion implantation results in atomically dispersed catalytic agents with high surface to volume ratio. Pt ions were implanted into the surface of Al2O3 catalytic supporter and its H2 generation property was measured for DME reforming catalyst. In this talk, a newly developed, non-gaseous plasma immersion ion implantation technique and its applications would be shown and discussed.

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Irradiation enduced In-plane magnetization in Fe/MgO/Fe/Co multilayers

  • Singh, Jitendra Pal;Lim, Weon Cheol;Song, Jonghan;Kim, Jaeyeoul;Asokan, K.;Chae, Keun Hwa
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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    • pp.188.1-188.1
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    • 2015
  • For present investigation Fe/MgO/Fe/Co multilayer stack is grown on Si substrate using e-beam evaporation in ultrahigh vacuum. This stack is irradiated perpendicularly by 120 MeV $Ag^{8+}$ at different fluences ranging from $1{\times}10^{11}$ to $1{\times}10^{13}ions/cm^2$ in high vacuum using 15UD Pelletron Accelerator at Inter University Accelerator Centre, New Delhi. Magnetic measurements carried out on pre and post irradiated stacks show significant changes in the shape of perpendicular hysteresis which is relevant with previous observation of re-orientation of magnetic moment along the direction of ion trajectory. However increase in plane squareness may be due to the modification of interface structure of stacks. X-ray reflectivity measurements show onset of interface roughness and interface mixing. X-ray diffraction measurements carried out using synchrotron radiation shows amorphous nature of MgO and Co layer in the stack. Peak corresponding body centered Fe [JCPDS-06-0696] is observed in X-ray diffraction pattern of pre and post irradiated stacks. Peak broadening shows granular nature of Fe layer. Estimated crystallite size is $22{\pm}1nm$ for pre-irradiated stack. Crystallite size first increases with irradiation then decreases. Structural quality of these stacks was further studied using transmission electron microscopic measurements. Thickness from these measurements are 54, 36, 23, 58 and 3 nm respectively for MgO, Fe, MgO, Fe+Co and Au layers in the stack. These measurements envisage poor crystallinity of different layers. Interfaces are not clear which indicate mixing at interface. With increase fluence mixing and diffusion was increased in the stack. X-ray absorption spectroscopic measurements carried out on these stacks show changes of Fe valence state after irradiation along with change of O(2p)-metal (3d) hybridized state. Valence state change predicts oxide formation at interface which causes enhanced in-plane magnetization.

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미강유중(米糠油中)의 Sterol조성(組成) (Sterol Composition of Rice Bran Oil)

  • 정태명;양민석;하봉석
    • Applied Biological Chemistry
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    • 제27권2호
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    • pp.119-128
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    • 1984
  • 미강유(米糠油)의 부(不)검화물(化物)을 분석(分析)하여 sterol조성(組成)을 살펴본 결과(結果)는 다음과 같았다. 4-Desmethylsterol로서는 10개가 동정(同定)되었으며 이 중(中) sitosterol이 주성분(主成分)을 이루고 있었다. 2개의 소량성분(少量成分)인 ${\Delta}^7$-stigmastenol(3%)과 ${\Delta}^7$-avenasterol(1%)를 제외(除外)하면 모두가 ${\Delta}^5$-sterol였으며 소위(所謂) ${\Delta}^5$형(型) sterol분포(分布)를 보이고 있었다. 4-monomethylsterol fraction에서는 9개가 확인(確認)되었으나 cycloeucalenol, citrostadienol, gramisterol가 주성분(主成分)이었다. 환계(環系)의 구조가 다양(多樣)하여 sterol의 생합성경로(生合成經路)의 중간단계(中間段階)임을 보여주고 있다. 4,4-Dimethylsterol(triterpene alcohol)로서는 4개가 동정(同定)되었으나 이들은 모두 9,19-cyclopropanering을 가지고 있다. 이들중(中) sterol생합성(生合成)의 초기단계(初期段階)의 물질(物質)인 cycloartenol와 24-methylenecyclo-artenol가 이 fraction의 96%를 점(占)하고 있는 것으로 봐서 미(米)강의 4,4-dimethylsterol는 짧은 경로(經路)를 거쳐 쉽게 4-monomethylsterol로 전환(轉換)되는 것 같다. Side chain에서 E-, Z-관계(關係)인 이성체(異性體)가 4-desmethylsterol로서는 fucosterol와 ${\Delta}^5$-avenasterol가 그리고 4-monomethylsterol로서는 28-isocitrostadienol와 citrostadienol로서 각각 1쌍식이 검출(檢出)된 것으로 미루어 볼때 sterol의 생합성과정(生合成過程)에서 side chain에서 보다 환계(環系)에서 먼저 변환(變換)이 일어나는 것으로 보아진다.

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함안군북지구(咸安郡北地區)의 지질(地質)과 동광상(銅鑛床) (Geology and Ore Deposits in the Haman-Kunbuk Copper District)

  • 문정욱;김명환;이지헌;최충정
    • 자원환경지질
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    • 제3권2호
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    • pp.55-73
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    • 1970
  • The district investigated covers the central and southern portions of the Uiryong Quadrangle amounting to $40km^2$ in area and is bounded approximately by geographical coordinates of $128^{\circ}$ 28' $40^{{\prime}{\prime}}{\sim}128^{\circ}$ 24' 25"E in longitude and $35^{\circ}10{\prime}{\sim}35^{\circ}14^{\prime}06^{{\prime}{\prime}}N$ in latitude. The purpose of this investigation was to provide basic information in drawing up a comprehensive development plan of the copper ore deposits known to exist in the HamanKumbuk district with special emphasis given to the ascertainment of geological and paragenetic characteristics. The area consists chiefly of shale, sandy shale and chert, all belong to Kyongsang System of Cretaceous age. Intruded into these rocks are andesite, granodiorite, basic dikes, and acidic dikes. The mineralization which took place in the area, consists of mostly fissure-filling vein deposits, numbering several tens, with varying magnitudes. The fissures and shear zones created in rocks, such as chert and granodiorite, hosted the deposition of mineralizing vapors and/or hydrothermal solutions along their openings. The strike lengths of these veins vary from 50 to 600 meters in extension and 0.1 to 3 meters in width. Although the degree of fluctuation in width is great, it averages 0.3m. The stuctural patterns, which apparently affected the deposition of veins, are fissure patterns, trend NS to $N30^{\circ}W$, and steep-pitching tension fractures as well as normal fault pattern. Ore minerals associated with vein matters are primarily chalcopyrite and small amounts of scheelite, cobaltiferous arsenopyrite, and gold and silver intimately associated with sulphide minerals. Associated with these ore mineral are pyrite, pyrrhotite, magnetite, specularite and arsenopyrite. Gangue minerals noted are quartz, calcite, chlorite, tourmaline and hornblende. In terms of the compositions of associated minerals, the vein deposits in the district could be grouped under the following four categories: 1. Pyrrhoitite, Arsenopyrite, Gold and Silver Bearing Copper Vein (Type I) 2. Calcite-Scheelite-Copper Vein (Type II) 3. Magnetite-Pyrite-Copper Vein (Type III) 4. Tourmaline Copper Vein (Type IV) Of the four types, the first and the fourth are presently yielding relatively higher grades: of copper ores and concentrates. The estimated ore reserves total some 222,000 metric tons with the following breakdown in terms of metal contents: Name of Mines Au(g/t) Ag(g/t) Cu(%) Reserves(M/T) Kunbuk 15.92 78.69 6,074 60.498 Cheil Kunbuk - - 1.040 60,847 Haman - - 2.688 101,204 222,549 As rehabilitation of old workings and/or exploration of veins at depth proceed, additional estimation of ore reserves may become apparent and necessary. With regard to the problem of beneficiation and upgrading of low-grade ores in the district, it would be advisable to make decisions on location, treating capacity and mill flowsheet after sufficient amount of exploration is completed as suggested in the report.

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의성지역 백악기 암석에 대한 고자기 연구 (Palaeomagnetism of Cretaceous Rocks in the Ǔisǒng Area, Kyǒngsang Basin, Korea)

  • 김인수;이현구;윤혜수;강희철
    • 자원환경지질
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    • 제26권3호
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    • pp.403-420
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    • 1993
  • The Cretaceous Kyongsang Basin is known to be composed of several tectonic blocks (or subbasins) with each distinct stratigraphic succession. The study area represents a major part of one of these blocks, i. e. the $\check{U}is\check{o}ng$ block. The area is charaterized by a suite of WNW-trending sinistral strike-slip faults as well as a number of ring faults. A total of 292 independently oriented core samples were drilled from 23 sites, covering virtually all the formations of the Cretaceous $Ky\check{o}ngsang$ Supergroup. Alternating field and thermal demagnetization experiments were conducted to reveal the primary magnetization. Due to the homoclinal nature of the strata in the area, it was not possible to make use of the conventional fold test It is, however, believed that the primary remanent components have been obtained from the majority of the formations, considering the similarity of the palaeomagnetic pole positions with those of contemporary strata of other blocks and the existence of antiparallel reversed remanence. It was found neither any significant difference in magnetic declination on each side of the strike-slip faults nor systematic change of magnetic declination with distance from the fault-line. This does not support such a block rotation hypothesis associated with the strike-slip faulting in the area as alleged by some authors. The samples from the outcrops on or near the fault-lines were severely overprinted by the recent magnetic fields regardless of age and lithology. Epithermal Au-Ag-Cu-Pb-Zn mineralizations are known along some fault lines in the area. It is interpreted that these two facts are closely related with fluid circulations along the fracture zones caused by fault activities. In regard to the age of the strata as deduced from the magnetostratigraphic consideration, the $Ch\check{o}mgok$ formation and the lower strata should be older than Barremian or 124 Ma. The age of volcanics of the $Yuch^{\prime}\check{o}n$ Group sampled in this study should be younger than Campanian or 83 Ma.

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이온-교환 크로마토그래피를 활용한 유기산 분석: 매립지 침출수의 영향을 받은 지하수에 대한 적용 (Analysis of Aliphatic Carboxylic Acids Using Ion-Exchange Chromatography: Application to Groundwater Affected by Landfill Leachates)

  • 전수현;고동찬;고경석
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제12권2호
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    • pp.55-64
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    • 2007
  • 생활 폐기물 매립장 침출수에 의해 오염된 지하수에 포함되어 있는 유기산($C_1-C_6$ aliphatic carboxylic acids)들의 정량 분석을 위해서 짧은 분석시간 안에 무기 음이온 뿐만 아니라 유기산까지 정량이 가능한 ion-exchange chromatography를 이용하여 침출수에 용존되어 있는 유기산을 정성 정량하였고, 검출된 유기산의 특성을 평가하였다. 분석 과정에서 $Cl^$, $Br^-$ 등의 halide 이온들의 유기산에 대한 피크 간섭을 줄이기 위해서 이들을 제거하는 전처리를 시료 주입 전에 적용하였다. 음이온 분석과 동일한 분석조건에서 음이온의 간섭을 최소화 하면서 정량이 가능한 유기산들을 선별하였고, 이들 유기산 중에서 음이온의 간섭을 받지 않는 fomate, acetate, propionate, pyruvate, succinate, oxalate에 대해서 정량 분석을 실시하였다. 본 실험에 사용된 유기산의 linear dynamic range는 0.5 mg/L에서부터 20 mg/L까지로 결정하였다. 이 분석법을 쓰레기 매립지 침출수와 주변 지하수에 대해 용존된 유기산과 무기 이온의 정량에 적용하여 높은 농도의 pyruvate와 낮은 수준의 formate와 acetate가 검출되었다. 지하수의 pyruvate 농도는 $Cl^-$, $HCO_3^-$ 농도와 높은 상관성을 보이고, 매립지에서 멀어질수록 농도가 감소하여, pyruvate는 매립지 침출수로부터 유래되었다고 추정되었다.

유채 잔유물의 녹비 이용에 따른 벼 생육특성 및 잡초발생 억제효과 (Effects of Rape Residue as Green Manure on Rice Growth and Weed Suppression)

  • 최봉수;성좌경;이상수;남재작;홍승길;김록영;양재의;옥용식
    • 한국환경농학회지
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    • 제29권2호
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    • pp.109-114
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    • 2010
  • 수확기 벼의 간장은 모든 처리구에서 비슷하게 생육하였으나 수장은 녹비환원구의 70% 시비구(17.5 cm)에서 관행재배구(16.4 cm)보다 촉진시켰다. 수확기 벼의 지상부 잎과 줄기의 생체중은 유채 잔유물 녹비환원구의 30% 시비구에서 관행재배구와 비슷한 수준이었다. 벼의 건물중에서도 생체중과 비슷하였으며, 녹비환원구의 70% 시비구에서는 이삭중을 19% 증가시켰다. 또한 유채 잔유물의 환원에 따른 벼의 주당수수와 1수영화수는 관행재배구에 비해 녹비환원구의 70% 시비구에서 비슷하거나 오히려 증가하였다. 한편 벼의 등숙율은 관행재배구의 91%와 비교하여 유채 잔유물 환원구에서 낮아지는 것(79-85%)으로 나타났으나, 정조수량은 유채 잔유물 환원구의 70% 시비구에서 496.4 g/pot으로 가장 높았다. 각 처리구별 벼의 수량으로부터 산출한 수량지수는 녹비환원구의 70% 시비구에서 125.4로 관행재배구보다 수량이 증가하였다. 잡초발생량은 관행재배구에서 37본으로 가장 많았으며, 유채 잔유물 환원구에서는 11.7-15.7본으로 관행재배구보다 현저히 감소시켰다. 잡초의 건물중은 관행재배구의 25.1 g/pot에 비해 유채 잔유물 환원구의 시비량이 많은 처리구부터 각각 11.8, 12.2 및 6.0 g/pot으로 현저히 감소시키는 것으로 나타났다.

Total Dietary Fiber and Mineral Absorption

  • Gordon, Dennis-T.
    • Journal of Nutrition and Health
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    • 제25권6호
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    • pp.429-449
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    • 1992
  • The consumption of foods rich in TDF should not be associated with impaired mineral absorp-tion and long-term mineral status. In surveys of populations consuming high amounts of TDF e.g Third World populations and vegetarinas gross deficiencies in mineral nutrition have not been noted. If mineral status is low among these groups it is most likely caused by the inadequacy or imbalance of the diet and not by the TDF. The key word is interaction which should be inte-rpreted in dietary imbalances that produce nut-rient deficiencies. There are no strong data to support the concept that TDF inhibits mineral absorption through a binding chelation mechanism. Limited data sug-gest that positively charged groups on polymers such as chitosan and cholestyramine will decrease iron absorption in humans and animals. Because TDF does not contain positively charged groups future research should be directed at the possible role of protein consumed along with TDF and the combination of effects on mineral nutrition Phytic acid is acknowledged as a potent chela-tor of zinc. However its association with zinc and its propensity to lower Zn bioavaiability may enhance the absorption of other elements notably copper and iron. The importance of interactions among nutrients including TDF will gain addi-tional attention in the scientific community. Soluble and insoluble dietary fiber function di-fferently in the intestine. Insoluble fibers accele-rate movement through the intestine. Soluble die-tary fibers appear to regulated blood concentra-tions of glucose and cholesterol albeit by some unknown mechanism. In creased viscosity produ-ced by the SDF in the intestine may provide an explanation of how this class of polymers affects plasma glucose cholesterol and other nutrients. Employing a double-perfusion technique in the rat we demonstrated that viscosity produced by SDF will delay transfer of zinc into the circulatory system. This delayed absorption should not be interpreted as decreased utilization. A great deal of additional research is required to prove the importance of luminaly viscosity produced by SDF on slowing nutrient absorption or regulating bllod nutrient homeostasis. Increased intake of TDF in the total human diet appears desirable. A dietary intake of 35g/day should not be considered to have a negative effect on mineral absorption. It is important to educate people that an intake of more than 35g TDF/day may cause an imbalance in the diet that can adve-rsely affect mineral utilization. Acknowledgments. Appreciation is given to Dr. George V. Vahouny(deceased) who was intense a great competitor in and out of science and who gave the author inspiration Portions of this work were supported by the University of Missouri Ag-ricultural Station and by a grant from the Univer-rch Support Grant RR 07053 from the National Institutes of Health. Contribution of the Missouri Agriculatural Experiments Station Journal Series No. 10747.

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비경구 투여한 Streptococcus mutans 균체 및 Glucosyltransferase에 대한 마우스의 면역항체반응 (ANTIBODY PRODUCTION BY PARENTERAL ADMINISTRATION OF STREPTOCOCCUS MUTANS AND GLUCOSYLTRANSFERASE IN MICE)

  • 양규호;정미;정진;장미영;오종석;나희삼;강인철;이현철
    • 대한소아치과학회지
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    • 제30권1호
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    • pp.61-68
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    • 2003
  • 치아우식증을 예방하기 위한 백신연구를 위하여 주원인균인 Sterptococcus mutans 균체항원과 이 균에서 분리한 glucosyltransferase (GTF)를 항원으로 하고 이에 면역조절기능이 있는 retinoic acid (RA)를 첨가하여 투여경로와 백신조성이 이들 항원에 대한 면역반응에 미치는 영향을 실험하였다. 균체항원(Ingbritt strain)을 마우스의 피하에 Complete Freund's Adjuvant와 함께 투여하여 생산되는 혈청내 응집항체가는 serotype e (LM-7)와는 강한 교차반응을 보였으나 serotype f (OMZ-175)와는 거의 교차반응을 일으키지 않았다. 면역혈청내 항-GTF 및 항-Ag I/II 항체중 항-GTF IgA는 피하로 투여시 전혀 검출되지 않았으나 이에 RA를 첨가하면 다량의 항체 생산을 관찰하였고 그 정도는 경구투여시의 생산량을 능가하였다. GTF를 alum과 함께 투여하여 생산되는 혈청내 항-GTF 항체중 IgM은 피하로 투여시 상당량이 검출되었고 RA를 첨가하면 그 생산이 증가되었으며 경구로 투여시 대조군에 비하여 약간증가를 보였으나 피하투여시의 그것에는 미치지 못하였다. GTF-특이 IgG는 경구투여시는 전혀 검출되지 아니하였고, 피하투여시에만 현저한 증가를 보였으며, RA첨가는 이에 영향을 미치지 못하였다. 항-GTF IgA는 피하로 투여시 전혀 검출되지 아니하였으나 이에 RA를 첨가하면 증가된 항체생산을 관찰하였고 그 정도는 경구투여시의 생산량을 능가하였다. 이상의 실험성적은 GTF에 대한 항체생산은 투여경로와 항원의 종류에 따라 다양한 반응을 나타내며 RA는 이를 백신에 첨가하면 피하경로를 이용하여 면역하더라도 경구투여와 유사한 IgA-매개 면역반응으로 조절시킬 수 있는 가능성을 나타내었다.

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