• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.302-303
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• 2010

Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

• 한국광물학회지
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• 제32권2호
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• pp.87-102
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• 2019

Pallancata 은 광산은 페루 수도 리마로부터 남동방향 약 520 km 떨어진 Ayacucho region 내에 위치한다. 광산일대의 주변 지질은 대부분 신생대의 화산암류로 구성되며 일부 관입암류가 관찰되며 구성암류는 응회암, 안산암질 용암, 안산암질 응회암, 화산쇄설성 용암, 화산 쇄설암, 유문암 및 석영몬조라이트이다. 이 광산은 응회암내에 발달된 NW, NE 및 EW 방향의 구조대를 따라 충진한 100여개의 석영맥들로 구성된다. 이들 석영맥의 은 품위는 40~1,000 g/t, 맥폭은 0.1~25 m 정도이고 연장성은 최대 3,000 m 정도이다. 석영맥은 대상, 정공, 괴상, 각력상, crustiform, colloform 및 comb 조직 등이 관찰된다. 모암변질작용은 규화작용, 견운모화작용, 황철석화작용, 녹니석화작용 및 점토화작용 등이 관찰된다. 산출광물은 석영, 방해석, 옥수, 빙장석, 형석, 금홍석, 저어콘, 인회석, 철산화물, REE계 광물, 크롬산화물, Al-Si-O계 광물, 황철석, 섬아연석, 황동석, 방연석, 에렉트럼, proustite-pyrargyrite, pearceite-polybasite 및 acanthite 등이다. 이 광산의 광물공생군과 화학조성을 토대로 구한 은 광화작용의 생성온도와 황분압($f_{s2}$)은 각각 $118{\sim}222^{\circ}C$ 및 $10^{-20.8}{\sim}10^{-13.2}atm.$의 범위를 갖는다. 따라서 이 광산의 석영맥 조직, 산출광물, 화학조성 및 은 광화작용의 형성환경 등을 토대로, 이 광산의 은 광물들은 모암과의 반응에 의한 약산성화된 열수용액으로부터 순환천수의 혼입에 의한 냉각 및 비등에 의해 비교적 낮은 형성온도, 유황분압 및 산소분압하에서 침전되었으며 이 광산의 광상형은 전형적인 천열수 intermediate sulfidation형에 해당된다.

• 한국광물학회지
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• 제15권1호
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• pp.1-10
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• 2002

이 논문은 온산공업단지 내 화강암의 풍화 및 토양화 과정, 그리고 토양 내 중금속 오염과 토양 광물간의 관계에 관한 연구이다. 프로화일 연구를 위해 각 깊이별로 토양시료를 채취하여 각 샘플에 대한 실험분석을 실시하였다. X선 회절분석 결과 주 구성 점토광물은 캐올린 광물과 버미큘라이트, 그리고 미량의 일라이트이다. 포름아마이드 처리를 통해 프로화일 내 토양 중의 캐올린 광물의 종류에 대해 분석한 결과 프로화일 하부에 존재하는 캐올린 광물은 대부분 할로이사이트 임이 밝혀졌으며, 지표면으로 갈수록 상대적으로 캐올리나이트에 대한 할로이사이트의 양이 감소하는 경향을 보이는데, 이는 상부로 갈수록 할로이사이트에서 캐올리나이트로의 전환이 이루어지고 있음을 의미한다. $110^{\circ}C,\;300^{\circ}C,\;550^{\circ}C$ 열처리를 한 결과 X선회절분석 그래프 상의 $10\;{\AA}에서\;14\;{\AA}$ 사이의 피크가 분화된 형태를 보여주는 것이 관찰된다. 이는 시료상에 수산화알루미늄 혼합층 버미큘라이트가 존재함을 지시한다. 이것은 구연산나트륨 처리실험을 통해 버미큘라이트 층간 불순 알루미늄 이온을 추출하여 원형상으로 전환시킴으로써 열처리시 $14\;{\AA}$피크가 다시 $10\;{\AA}$으로 변화하는 것을 관찰함으로써 재확인하였다. 토양의 수소이온농도 분포 양상이 하부에서 3.9, 상부에서 3.6으로 상부로 갈수록 산성화경향이 심해지는 경향을 보여주는데, 이는 산성화된 토양에서 안정적으로 나타나는 수산화알루미늄 혼합층 버미큘라이트의 존재를 뒷받침하고 있다. 토양 내 중금속 이온의 존재양상에 대한 연구를 위해 연속추출실험을 실시하였다. 그 결과 상대적으로 많은 양의 중금속 이온이 프로화일의 상부의 철/망간 산화물과 유기물에 흡착되어 있으며 점토광물에는 적은 양만이 흡착되어 있는 것으로 밝혀졌다. 이러한 결과는 대부분의 중금속 오염물들이 상부 토양에 농집되어 있고 점토광물에는 낮은 중금속 함량을 보여주는 것은 산성화된 토양을 이루고 있는 주 점토광물인 캐올린광물과 수산화알루미늄 혼합층 버미큘라이트가 낮은 흡착능력을 가지고 있기 때문인 것으로 판단한다.

• Journal of the korean society of oceanography
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• 제34권2호
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• pp.122-131
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• 1999

This study examined the relationship between the sediment pollution and the occurrence of polychaetes in a heavily polluted saltwater lake, Lake Shihwa on the west coast of Korea, separated from the sea by a dike in 1994. The species composition of polychaete assemblage was compared with that found off the lake in Kyeonggi Bay. Environmental variables investigated both in and off the lake were the grain size distribution, chemical oxygen demand(COD) and metal concentrations (Al, Fe, Mn, V, Co, As, Pb, Cr and Cu) in the sediment. We sampled sediments at 10 stations in the lake and 25 stations in Kyeonggi Bay using a modified van Veen grab. The levels of COD, chromium, and copper in sediments were much higher in Lake Shihwa than in Kyeonggi Bay. Differences in the species composition were found along the pollution gradient. An azoic zone was observed in the most heavily polluted area at the upper reach of the lake and the Polydora ligni zone in the center of the lake. Bottom fauna were diverse in Kyeonggi Bay; however, Heteromastus filiformis predominated in the organically enriched sediment. The density of dominant species differed along the pollution gradient. The highest density or H. filiformis was round at the COD level or around 5.8 mg/g. The COD level in the sediment where P. ligni predominated was tow-fold higher than that where H. filiformis occurred in large numbers. The chromium and copper contents at which P. ligni showed a maximum abundance were 120 mg/kg and 127 mg/kg, respectively. The density of H. filiformis was highest at concentrations of 56 mg/kg chromium and 13 mg/kg copper.

• 대한본초학회지
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• 제23권2호
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• pp.123-136
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• 2008

Objectives : To estimate the value of the Gyungokgo as therapeutic agent preventing against aging with an analysis of the ingredients and the bio-activating effects by enzymologic methods. Methods : A quantitative analysis of general ingredients' of the Gyungokgo's extract was done first. The effects on electronic donating ability, SOD-like activity, nitric oxide inhibition, xanthine oxidase inhibition, whitening effect have been investigated in the physiological activity measurement of function experiment. Results : The contained hydrolyzed amino acid is Valine, Aspartic acid, Arginine, Isoleucine and the contained free amino acid is Arginine, Phenylalanine, Valine, Glycine. The derivative of free amino acid is Phosphoserine, Carnocine, ${\gammer}$-Aminoisobutyric acid. And the Gyungokgo contains 14 species of minerals, K>Na>Ca>Mg>Fe>Al>Mn. Then, to assure of the Gyungokgo's anti-oxidation, these following subjects -polyphenol, electronic donating ability, SOD-like activity, nitric oxide inhibition, xanthine oxidase inhibition, tyrosinase inhibation- are analyzed and show high activity especially the most in chloroform extracts, (every ingredients written by the order of high amount) Conclusions : The Gyungokgo contains many materials functioning as anti-oxidation, neurotransmitter, anti-fatigue and immune agent.

• 한국해양학회지
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• 제11권2호
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• pp.64-70
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• 1976

기수호인 화진포에 대한 생태학적인 연구가 여러 차례에 걸쳐 실시된 바 있으나( 홍사오외 1969; 엄규백, 1971, 1973; 전승관 외 1969; 변충규 외 1975) 현생퇴적물에 대한 퇴적환경적 연구는 실시된 바 없다. 따라서 본 연구에서는 화진포의 퇴적물에 대한 조직표준치와 분포 특성 및 호수퇴적물중에 포함된 점토광물의 종류와 호수퇴적물의 화학성분을 퇴적과정의 퇴적요인으로 하여 본 역의 현생퇴적환경특성을 밝히고자 한다.

• 한국대기환경학회지
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• 제25권2호
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• pp.108-121
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• 2009

The suspended particulate matters have been collected on membrane filters and glass fiber filters by an 8-stage cascade impactor for 2 years (Sep. 2005${\sim}$Sep. 2007) in Kyung Hee University-Global Campus located on the border of Yongin and Suwon. The 20 chemical species (Al, Mn, Si, Fe, Cu, Pb, Cr, Ni, V, Cd, Ba, $Na^+$, ${NH_4}^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$) were analyzed by an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on these chemical information, the PMF receptor model was applied to identify the source of ambient size-by-size particulate matters. The receptor modeling is the one of the statistical methods to achieve resonable air pollution management strategies. A total of 10 sources was identified in 9 size-ranges such as long-range transport, secondary aerosol, $NH_{4}NO_{3}$ related source, coal combustion, sea-salt, soil, oil combustion, auto emission, incineration, and biomass burning. Especially, the secondary aerosol source assorted in fine and coarse modes was intensively studied.

• 한국환경과학회지
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• 제17권10호
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• pp.1147-1154
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• 2008

Road runoff, one of non-point source pollutants, contains various heavy metals, most of which flow into discharge waters without being treated. The mechanism of removing the heavy metals in water is similar to that of removing micro-particles. Therefore, it is considered that it is possible to remove a lot of the heavy metals contained in the road runoff by filtering or absorbing them. In this paper, performed has been a basic study on the characteristics of UNFS (Up Flow Non-Point Source Filtering System) using carbide pellet and zeolite pellet as double-layer filtering mediums to treat the road runoff. The removal rate with filtering and absorption time has been shown as follows: 29.0% for Cr; 27.8% for Cd; 25.7% for Fe; 25.4% for Co; 21.2% for Pb; ]9.6% for Zn; 18.2% for Al; 17.0% for Mn; 11.3% for Ni; 7.5% for Cu. The overall removal rate according to influx change has been shown to be approximately 30%, and the load of heavy metals flowing out in initial precipitation could be reduced by using carbide as a recycling filtering medium. When the removal as coarse particles settle is added up, it is expected that UNFS will result in a higher removal rate.

• 한국토양비료학회지
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• 제45권3호
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• pp.428-434
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• 2012

A fungal strain, capable of solubilizing insoluble phosphate under diverse temperature, pH and salt conditions was isolated from Waste Mushroom bed of Agaricus bisporus in South Korea. Based on 18S rRNA analysis, the strain was identified as Aspergillus awamori bxq33110. The strain showed maximum phosphate solubilization in AYG medium (525 ${\mu}g\;mL^{-1}$) followed by NBRIP medium (515 ${\mu}g\;mL^{-1}$). The strain solubilized $Ca_3(PO_4)_2$ to a greater extent and rock phosphate and $FePO_4$ to a certain extent. However $AlPO_4$ solubilizing ability of the strain was found to be very low. Glucose at the rate of 2% ($561{\mu}g\;mL^{-1}$) was found be the best carbon source for Aspergillus awamori bxq33110 to solubilize maximum amount of phosphate. However, no significant difference ($P{\leq}0.05$) in phosphorus solubilization was found between 1% and 2% glucose concentrations. $(NH_4)_2SO_4$ was the best nitrogen source for Aspergillus awamori bxq33110 followed by $NH_4Cl$ and $NH_4NO_3$. At pH 7, temperature $30^{\circ}C$ and 5% salt concentration (674 ${\mu}g\;mL^{-1}$) were found to be the optimal conditions for insoluble phosphate solubilization. However, strain Aspergillus awamori bxq33110 was shown to have the ability to solublize phosphate under different stress conditions at $30-40^{\circ}C$ temperature, pH 7-10 and 0-10% salt concentrations indicating it's potential to be used as bio-inoculants in different environmental conditions.

• 열처리공학회지
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• 제11권2호
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• pp.140-149
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• 1998

The graphitization is affected by the addition of small amount of the elements, such as Si, Al, Ni, B, Cr and Mn etc. Boron is well known as the most effective element for the graphitization of cementite in high carbon steels. But a study on quantitative analysis of B effect on the graphitization is few reported. Therefore the effect of boron addition in Fe-0.65%C-1.0%Si-0.5%Mn steels on the graphitization is investigated quantitatively using hardness tester, optical microscope and scanning electron microscope, neutron induced microscopic radiography. The graphitization in high carbon steels is promoted with 0.003~0.005%B addition. But the graphitization in steels which has no boron takes long holding time at $680{\sim}720^{\circ}C$. The hardness of quenched steel containing 0.003%B is higher than that of 0.005%B added steel due to complete dissolution of fine graphites into the austenite. The 0.003%B added high carbon steel graphitized at $680^{\circ}C$ for 25hr is useful steel for the agricultural implements and automobile parts which needed a good formability and high hardness.