• 제목/요약/키워드: Al/Cu

검색결과 2,084건 처리시간 0.027초

2000~2002년 우리나라에서 관측된 황사의 화학 조성 및 특성 (Chemical Composition and Features of Asian Dust Observed in Korea (2000~2002))

  • 신선아;한진석;홍유덕;안준영;문광주;이석조;김신도
    • 한국대기환경학회지
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    • 제21권1호
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    • pp.119-129
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    • 2005
  • The ambient TSP data measured at Seoul, Incheon. Taean, Daegu, Busan in Korea were used to explain the chemical composition and general features of Asian Dust (AD) observed in Korea. 9 episodes out of 19 were sampled from 2000 through May 2002, and measurements were conducted covering ionic and metal components with mass concentration. The results showed that daily averaged mass concentration (TSP) during the AD episodes was 458 $\mu\textrm{g}$/㎥, and ionic and metal concentrations were 27.93 $\mu\textrm{g}$/㎥ and 71.7 $\mu\textrm{g}$/㎥, respectively, accounting for 6.1 % and 15.5% of the total aerosol mass. TSP concentrations during episodes were varied from 120 to 1742 $\mu\textrm{g}$/㎥ according to the impact of Asian Dusts and had a tendency of showing higher values at sites in the west side of Korea, which can be explained by the effect of diffusion and deposition. In this study, ionic components like Ca (NO$_3$)$_2$, CaSO$_4$, NaNO$_3$, Na$_2$SO$_4$ were prominent types in secondary aerosol during AD periods and also indicated that V, Co as well as soil elements such as Ca, Fe, Mg, Mn, K correlated well with Al, while Cu, Cd, Pb, Zn didn't agree well with it. In addition, enrichment factors (EFs) for each metal component were obtained to provide simple information about source contribution of Asian Dust, and the results were compared with those from other AD studies. In this study, the results showed that aerosol properties in Korea during the Asian Dust were considerably different from those of general atmospheric condition and specially varied from case to case rather than site to site, which implies that there are certain variations in the soil of source region, pathways of air mass, and meteorological condition. For the enhanced study, those factors should be combined with the features of Asian Dust resolved from this study.

황해 폐기물 투기해역(서해병) 표층 퇴적물의 금속원소 분포 (Concentration of metallic elements in surface sediments at a waste disposal site in the Yellow Sea)

  • 고혁준;최영찬;박성은;차형기;장대수;이충일;윤한삼
    • 한국환경과학회지
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    • 제22권7호
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    • pp.787-799
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    • 2013
  • The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 mg $O_2/g{\cdot}dry$, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.

추출방법에 따른 대나무(왕대) 추출물의 화학성분 및 생리활성 (Chemical Components and Physiological Activities of Bamboo (Phyllostachys bambusoides Starf) Extracts Prepared with Different Methods)

  • 주인옥;정기태;류정;최정식;최영근
    • 한국식품과학회지
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    • 제37권4호
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    • pp.542-548
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    • 2005
  • 대나루(왕대)를 여러 가지 방법으로 추출하고 그 추출액의 화학 성분을 분석하였다. 대나무 추출액의 pH는 5.0-5.5였고, 가용성고형분과 총페놀 함량은 알코올 추출액이 각각 $13.7^{\circ}Brix$와 0.42%로 가장 높았으며, 증발잔사는 직접가열 추출액이 3.8%로 가장 높았다. 무기성분은 K이 가장 높은 함량을 보였으며, 추출방법에 따라서는 간접가열이 가장 높은 무기물 함량을 나타내었다. 중금속은 Al, Cr, Cu, Mn, Ni, Pb, Zn, 등이 검출되었으며, 유해중금속 중 As, Cd, Hg는 검출되지 않았고 Cr, Pb는 극미량 검출되었다. 폴리페놀은 catechin, chlorogenic acid, caffeic acid, 3-hydroxy benzoic acid, ferulic acid등 5종이 확인되었으며 이중 3-hydroxy benzoic acid와 catechin이 주종을 이루는 것으로 나타났다. 유리당은 galactose, glucose, fructose 및 sucrose가 검출되었으며 glucose와 sucrose의 함량이 가장 높았다. 유기산은 citric acid, tartaric acid, malic acid, succinic acid, acetic acid 등이 검출되었으나 직접가열 추출액은 tartaric acid가, 물 추출액과 알코올 추출액은 citric acid, tartaric acid 및 succinic acid가 검출되지 않았다. 항산화 활성은 간접가열 추출액과 알코올 추출액이 상업용 항산화제인 BHA와 ${\delta}-tocopherol$ 보다 우수하였다. 아질산염소거능은 pH 1.2와 3.0에서 효과가 우수하였으나 pH 6.0에서는 급격히 감소하였다. Tyrosinase 저해활성은 물 추출액이 가장 높았으며, SOD 유사활성과 ACE 저해활성은 간접가열 추출액이 가장 높았다. 식품 부패균에 대한 항균활성은 Bacillus subtilis, E. coli O157, Staphylococcus aureus에 대하여 높은 것으로 나타났다.

차량 운행에 따른 자동변속기유(ATF) 금속분 분석평가 연구 (A study on the evaluation of metal component in automatic transmission fluid by vehicle driving)

  • 이정민;임영관;도진우;정충섭;한관욱;나병기
    • 에너지공학
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    • 제23권2호
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    • pp.28-34
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    • 2014
  • 자동변속기유는 자동차의 자동변속기의 성능을 유지시키기 위해 사용되는 유체이다. 최근 자동차 제조사에서는 일반적으로 자동변속기유를 80000~100000 km 주행후 교환 또는 무교환을 보증하고 있지만 국내에서는 많은 운전자들이 50000 km 이하에서도 자동변속기유를 교환하고 있는 것으로 조사되었다. 빈번한 자동변속기유의 교환은 환경오염과 차량유지비용을 상승시키는 원인으로 작용되고 있다. 본 연구에서는 사용하지 않은 신유와 50000 km와 100000 km를 각각 주행한 뒤 회수된 자동변속기유를 대상으로 인화점, 연소점, 유동점, 동점도, 저온겉보기점도, 전산가, 금속분과 같은 물리적 특성을 분석하였다. 연구결과, 신유에 비해 사용유는 전산가, 유동점, 금속분이 증가되는 것을 확인하였지만, 두 종류의 사용유(50000 km, 100000 km)의 물리적 특성과 금속분 함량의 차이는 크지 않음을 알수 있었다.

Strain induced/enhanced ferromagnetism in $Mn_3Ge_2$thinfilms

  • ;;;신유리미;조성래
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
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    • pp.135-135
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    • 2010
  • In Mn-Ge equilibrium phase diagram, many Mn-Ge intermetallic phases can be formed with difference structures and magnetic properties. The MnGe has the cubic structure and antiferromagnetic(AFM) with Neel temperature of 197 K. The calculation predicted that the $MnGe_2$ with $Al_2Cu$-type is hard to separate between the paramagnetic(PM) states and the AFM states because this compound displays PM and AFM configuration swith similar energy. Mn-doped Ge showed the FM with Currie temperature of 285 K for bulk samples and 116 K for thin films. In addition, the $Mn_5Ge_3$ compound has hexagonal structure and FM with Curie temperature around 296K. The $Mn_{11}Ge_8$ compound has the orthorhombic structure and Tc is low at 274 K and spin flopping transition is near to 140 K. While the bulk $Mn_3Ge_2$ exhibited tetragonal structure ($a=5.745{\AA}$;$c=13.89{\AA}$) with the FM near to 300K and AFM below 150K. However, amorphous $Mn_3Ge_2$ ($a-Mn_3Ge_2$) was reported to show spin glass behavior with spin-glass transition temperature (Tg) of 53 K. In addition, the transition of crystalline $Mn_3Ge_2$ shifts under high pressure. At the atmospheric pressure, $Mn_3Ge_2$ undergoes the magnetic phase transition from AFM to FM at 158 K. The pressure dependence of the phase transition in $Mn_3Ge_2$ has been determined up to 1 GPa. The transition was found to occur at 1 GPa and 155 K with dT/dP=-0.3K/0.1 GPa. Here report that Ferromagnetic $Mn_3Ge_2$ thin films were successfully grown on GaAs(001) and GaSb(001) substrates using molecular beam epitaxy. Our result revealed that the substrate facilitates to modify magnetic and electrical properties due to tensile/compressive strain effect. The spin-flopping transition around 145 K remained for samples grown on GaSb(001) while it completely disappeared for samples grown on GaAs(001). The antiferromagnetism below 145K changed to ferromagnetism and remained upto 327K. The saturation magnetization was found to be 1.32 and $0.23\;{\mu}B/Mn$ at 5 K for samples grown on GaAs(001) and GaSb(001), respectively.

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공주제일광산 수계에 분포하는 지하수, 지표수, 토양 및 퇴적물의 환경지구화학적 특성과 중금속 오염 (Environmental Geochemistry and Heavy Matel Contamination of Ground and Surface Water, Soil and Sediment at the Kongjujuil Mine Creek, Korea)

  • 이찬희
    • 자원환경지질
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    • 제32권6호
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    • pp.611-631
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    • 1999
  • Enviromental geochemisty and heary metal contamination at the Kongjueil mine creek were underaken on the basis of physicohemical properties and mineralogy for various kinds of water (surface, mine and ground water),soil, precipitate and sediment collected of April and December in 1998. Hydrgeochemical composition of the water samples are characterized by relatively significant enricant of Ca+Na, alkiali ions $NO_3$ and Cl inground and surfore water, wheras the mine waters are relatively eneripheral water of the mining creek have the characteristics of the (Ca+Mg)-$(HCO_3+SO_4)$type. The pH of the mine water is high acidity (3.24)and high EC (613$\mu$S/cm)compared with those of surface and ground water. The range of $\delta$D and $\delta^{18}O$ values (relative to SMOW) in the waters are shpwn in -50.2 to -61.6% and -7.0 to -8.6$\textperthousand$(d value=5.8 to 8.7). Using computer program, saturation index of albite, calcite, dolomite in mine water are nearly saturated. The gibbiste, kaolinite and smectite are superaturated in the surface and ground water, respectively. Calculated water-mineral reaction and stabilities suggest that weathing of silicate minerals may be stable kaolinite owing to the continuous water-rock reaction. Geochemical modeling showed that mostly toxic heavy metals may exist larfely in the from of metal-sulfate $(MSO_4\;^2)$and free metal $(M^{2+})$ in nmine water. These metals in the ground and surface water could be formed of $CO_3$ and OH complex ions. The average enrichment indices of water samples are 2.72 of the groundwater, 2.26 of the surface water and 14.15 of the acid mine water, normalizing by surface water composition at the non-mining creek, repectively. Characteristics of some major, minor and rate earth elements (Al/Na, K/Na, V/Ni, Cr/V, Ni/Co, La/Ce, Th/Yb, $La_N/Yb_N$, Co/Th, La/Sc and Sc/Th) in soil and sediment are revealed a narrow range and homogeneous compositions may be explained by acidic to intermediate igneous rocks. And these suggested that sediment source of host granitic gneiss colud be due to rocks of high grade metamorphism originated by sedimentary rocks. Maximum concentrations of environmentally toxic elements in sediment and soil are Fe=53.80 wt.% As=660, Cd=4, Cr=175, Cu=158, Mn=1010, Pb=2933, Sb=4 and Zn=3740 ppm, and extremely high concentrations are found are found in the subsurface soil near the ore dump and precipitates. Normalizing by composition of host granitic gneiss, the average enerichment indices are 3.72 of the sediments, 3.48 of the soils, 10.40 of the precipitates of acid mine drainage and 6.25 of the soils near the main adit. The level of enerichment was very severe in mining drainage sediments, while it was not so great in the soils. mineral composition of soil and sediment near the mining area were partly variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. reddish variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. Reddish brown precipitation mineral in the acid mine drainage identifies by schwertmanite. From the separated mineralgy, soil and sediment are composed of some pyrite, arsenopyite, chalcopyrite, sphalerite, galena, malachite, goethite and various kinds of hydroxied minerals.

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SFIT형태를 이용한 SPUDT형 필터제작에 관한 기초실험 (The basic experiments for the fabrication of the SPUDT type Inter using the SFIT type filter)

  • 유일현
    • 한국정보통신학회논문지
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    • 제11권10호
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    • pp.1916-1923
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    • 2007
  • 대역통과용 표면 탄성파 필터 제작하기 위하여 Langasite 기판위에 빗살무의 변환기를 형성 시켜 모의실험을 수행하였으며, 전극재료로는 Al-Cu를 사용하였다. 모의실험을 바탕으로 입력단에는 IDT를 직렬형태로 연결시킨 block 형태로 하중을 가하는 전극 방법을 쓰고 출력 단은 withdrawal 형태로 하중을 가하는 방법을 써서 제작하였다. 이를 바탕으로 광대역의 SAW 필터 전극 설계 방식에 대한 적절한 위상조건도 얻고자 시도하였다. Langasite 기판위에 형성시킨 입출력 빗살무의 변환기 전극 수는 50쌍, 두께는 $5000\;{\AA}$으로 하였으며, 반사기 폭은 $3.6{\mu}m$으로 하였다. 그리고 hot전극과 반사기사이의 거리는 각각 $2.0{\mu}m\;2.4{\mu}m$로 제작하였고, hot전극에서부터 접지전극까지 간격은 $1.5{\mu}m$로 하였으며 전극 모양은 좌우 동일한 형상을 채택하였다. 제작한 필터의 주파수 특성은 중심주파수가 대략 190MHz정도, 대역폭은 7.8MHz 이하로 측정되었으며, matching 후 return-loss는 -18dB 이하이고, 리플 특성은 3dB 이하이며, 반사에 의한 잔향은 -25dB 이하로 측정되었다.

Energy utilization, nutrient digestibility and bone quality of broiler chickens fed Tanzania-type diets in different forms with enzymes

  • Chang'a, Edwin Peter;Abdallh, Medani Eldow;Ahiwe, Emmanuel Uchenna;Al-Qahtani, Mohammed;Mbaga, Said;Iji, Paul Ade
    • Journal of Animal Science and Technology
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    • 제61권4호
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    • pp.192-203
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    • 2019
  • A study was conducted to determine the influence of feed form and microbial enzyme supplementation on energy utilization, bone quality, and amino acid and mineral digestibility of broiler chickens. Four hundred and eighty Ross 308, day-old broiler chickens were randomly assigned to eight diets formulated from commonly used ingredients in Tanzania. A 2 (pellet or mash) ${\times}$ 4 (control, Axtra XB, Quantum Blue (QB) and Axtra XB + QB enzyme) factorial array in a completely randomized design having six replicates per treatment (10 birds per replicate) was used. Birds were raised in climate-controlled rooms in a 3-phase; starter (0-10 days), grower (11-24 days) and finisher (25-35 days). Apparent metabolizable energy (AME), metabolizable energy intake, net energy of production, energy retained as protein (REp), and efficiency of metabolizable energy use for energy and protein retention were higher (p < 0.05) in birds fed pelleted diets. The AME and REp was higher (p < 0.05) with enzyme supplementation. Ash content, weight, length, width and breaking strength of tibia bones were highest (p < 0.05) in birds on pelleted diets. Tibia bone traits were improved (p < 0.05) when enzymes were included, particularly in a combination of QB and Axtra XB. However, potassium, magnesium, and zinc contents were highest (p < 0.05) when QB was supplemented. Digestibility of all amino acids was higher (p < 0.05) in birds supplied with pellets and with enzyme supplementation for most amino acids, except for serine. There was a positive interaction (p < 0.05) between feed form and enzymes on lysine and phenylalanine digestibility. Digestibility of Ca, P, K, S, Zn, and Fe was higher (p < 0.05) in birds fed pelleted diets, while those on mashed diets had higher (p < 0.05) digestibility of Cu and B. The digestibility of P, K, and Zn was highest (p < 0.001) when QB was added, while Ca, P, S, and B digestibility was highest when a combination of Axtra XB + QB was applied. Pelleted diets with or without enzymes improved energy utilization, digestibility of amino acids, and minerals, and increased bone strength in broiler chickens.

3차원 기공구조를 이용한 정전기반 에너지 하베스팅 나노발전기 소자제조 (3D Porous Foam-based Triboelectric Nanogenerators for Energy Harvesting)

  • 전상헌;정정화;홍석원
    • 마이크로전자및패키징학회지
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    • 제26권1호
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    • pp.9-15
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    • 2019
  • 본 연구에서는 3차원 기공구조를 지닌 금속 및 고분자 소재를 이용한 수직 마찰모드의 정전기반 나노발전기(triboelectric nanogenerator, TENG) 제조기술을 소개하고 이에 관한 응용 연구를 수행하였다. 다양한 장점을 지닌 3차원 기공구조를 활용하여 설계된 간단하며 효율적인 나노발전기로, 반복적인 접촉/분리를 통해, 120 V에 이르는 순간 전압특성과 최대 출력 $0.74mW/m^2$을 획득하였다. 실제적인 응용 연구로 48개의 발광소자 구동 실험을 실시하였으며, 저전력 소비 전자소자 장치로의 응용 확장성을 확인하기 위해 회로 구성을 통한 커패시터 축적기능을 확인하였다. 본 연구에서 소개하는 정전기반 에너지 하베스팅 기술은 매우 경제적으로 제조할 수 있는 실용적인 접근방식으로, 반복적으로 가해지는 마찰에 의한 정전력을 효율적으로 획득하여 가까운 미래에 자가발전(self-powered)형 소형 전기소자 구동, 휴대형 전자기기 및 대규모의 전자 발전 장치에 적용 가능할 것으로 기대된다.

기반암에 따른 청풍지역 하상퇴적물의 지구화학적 특성 (Geochemical Characteristics of Stream Sediments Based on Bed Rocks in the Cheongpung Area)

  • 박영석;박대우;김종균;송영상;이장존
    • 자원환경지질
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    • 제39권6호
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    • pp.675-687
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    • 2006
  • 이 연구에서는 청풍지역 하상퇴적물에 대한 지구화학적 특성 규명을 통해, 주성분원소 및 미량원소에 대한 청풍지역의 자연배경치를 제시하고, 지구화학적 재해에 대해 예견하고자 한다. 이를 위해 물이 흐르고 있는 1차 수계를 대상으로 하상퇴적물시료를 채취하였고, 실험실에서 자연건조 시켰으며, 화학적 분석을 위해 알루미나 몰타르를 이용하여 200메쉬 이하로 분쇄하였다. 주성분원소 및 미량성분원소는 XRD, XRF, ICP-AES, NAA를 이용하여 분석하였다. 청풍지역 하상퇴적물의 기반암에 따른 지질집단별 지구화학적 특성 비교를 위해, 화강암질편마암지역, 메타텍틱편마암지역, 다도응회암지역, 유치역암 지역, 능주용암지역으로 분류하였다. 청풍지역 하상퇴적물 전체에 대한 주성분원소 함량은 $SiO_2\;47.31{\sim}72.81\;wt.%,\;Al_2O_3 \;11.26{\sim}21.88\;wt.%,\;Fe_2O_3\;2.83{\sim}8.39\;wt.%,\;CaO\;0.34{\sim}7.54\;wt.%,\;MgO\; 0.55{\sim}3.59\;wt.%,\;K_2O\;1.71{\sim}4.31\;wt.%,\;Na_2O\;0.56{\sim}2.28\;wt.%,\;TiO_2\;0.46{\sim}1.24\;wt.%,\;MnO\;0.04{\sim}0.27\;wt.%,\;P_2O_5\;0.02{\sim}0.45\;wt.%$이다. 청풍지역 하상퇴적물 전체에 대한 미량성분원소 및 희토류원소 함량은 $Ba\;700ppm{\sim}8990ppm,\;Be\;1.0{\sim}3.50ppm,\;Cu\;6.20{\sim}60ppm,\;Nb\;12{\sim}28ppm,\;Ni\;4.4{\sim}61ppm,\;Pb\;13{\sim}34ppm,\;Sr\;65{\sim}787ppm,\;V\;4{\sim}98ppm,\;Zr\;32{\sim}164ppm,\;Li\;21{\sim}827ppm,\;Co\;3.68{\sim}65ppm,\;Cr\;16.7{\sim}409ppm,\;Cs\;72{\sim}37.1ppm,\;Hf\;4.99{\sim}49.2ppm,\;Rb\;71.9{\sim}649ppm,\;Sb\;0.16{\sim}5.03ppm,\;Sc\;4.97{\sim}5ppm,\;Zn\;26.3{\sim}375ppm,\;Ce\;60.6{\sim}373ppm,\;Eu\;0.82{\sim}6ppm,\;Yb\;0.71{\sim}10ppm$의 범위를 보였다.