• 자원환경지질
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• 제31권4호
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• pp.297-310
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• 1998

Geochemical characteristics of environmental toxic elements at the Narim mine area were investigated on the basis of major, minor, rare earth element geochemistry and mineralogy. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in soils and sediments range from 11.57 to 22.21 and from 1.86 to 3.93, and are partly negative and positive correlation against $SiO_2/Al_2O_3$ (3.41 to 4.78), respectively. These suggested that sediment source of host granitic gneiss could be due to rocks of high grade metamorphism originated by sedimentary rocks. Characteristics of some trace and rare earth elements of V/Ni (0.33 to 1.95), Ni/Co (2.00 to 6.50), Zr/Hf (11.27 to 53.10), La/Ce (0.44 to 0.55), Th/Yb (4.07 to 7.14), La/Th (2.35 to 3.93), $La_N/Yb_N$ (6.58 to 13.67), Co/Th (0.63 to 2.68), La/Sc (3.29 to 5.94) and Sc/Th (0.49 to 1.00) are revealed a narrow range and homogeneous compositions may be explained by simple source lithology. Major elements in all samples are enriched $Al_2O_3$, MgO, $TiO_2$ and LOI, especially $Fe_2O_3$ (mean=7.36 wt.%) in sediments than the composition of host granitic gneiss. The average enrichment indices of major and rare earth elements from the mining drainage are 2.05 and 2.91 of the sediments and are 2.02 and 2.60 of the soils, normalizing by composition of host granitic gneiss, respectively. Average composition (ppm) of minor and/or environmental toxic elements in sediments and soils are Ag=14 and 1, As=199 and 14, Cd=22 and 1, Cu=215 and 42, Pb=1770 and 65, Sb=18 and 3, Zn=3333 and 170, respectively, and extremely high concentrations are found in the subsurface sediments near the ore dump. Environmental toxic elements were strongly enriched in all samples, especially As, Cd, Cu, Pb, Sb and Zn. The level of enrichment was very severe in mining drainage sediments, while it was not so great in the soils. Based on the EPA value, enrichment index of toxic elements is 8.63 of mining drainage sediments and 0.54 of soils on the mining drainage. Mineral composition of soils and sediments near the mining area were partly variable being composed of quartz, mica, feldspar, amphibole, chlorite and clay minerals. From the gravity separated mineralogy, soils and sediments are composed of some pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, goethite and various hydroxide minerals.

• Journal of information and communication convergence engineering
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• 제4권1호
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• pp.18-22
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• 2006

A small-sized gas identification system has been fabricated and characterized using an integrated gas sensor array and artificial neural-network. The sensor array consists of four thick-film oxide semiconductor gas sensors whose sensing layers are $In_{2}O_{3}-Sb_{2}O_{5}-Pd-doped\;SnO_2$ + Pd-coated layer, $La_{2}O_{5}-PdCl_{2}-doped\;SnO_2,\;WO_{3}-doped\;SnO_{2}$ + Pt-coated layer and $ThO_{2}-V_{2}O_{5}-PdCl_{2}\;doped\;SnO_{2}$. The small-sized gas identification instrument is composed of a GMS 81504 containing an internal ROM (4k bytes), a RAM (128 bytes) and four-channel AD converter as MPU, LEDs for displaying alarm conditions for three gases (liquefied petroleum gas: LPG, liquefied natural gas: LNG and carbon monoxide: CO) and interface circuits for them. The instrument has been used to identify alarm conditions for three gases among the real circumstances and the identification has been successfully demonstrated.

• 보존과학연구
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• 통권8호
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• pp.1-12
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• 1987

Fifty ancient Korean coins originated in Choson dynasty have been determined for 9 elements such as Sn, Fe, As, Ag, Co, Sb, Ir, Ru and Ni by instrumental neutron activation analysis and for 3 elements such as Cu, Pb, and Zn by atomicalsorption spectrometry. Bronze coins originated in early days of the dynasty contain as major constituents Cu, Pb and Sn approximately in the ratio 90 : 4 : 3, where as, those in latter days contain in the ratio 7 : 2 : 0. Brass coins which had begun in 17century contain as major constituents Cu, Zn and Pb approximately in the ratio 7 : 1: 1. The multivariate date have been analyzed for the relation among elemental contents through the variance-covariance matrix. The data have been fur theranalyzed by a principal component mapping method. As the results training set of 8class have been chosen, based on the spread of sample points in an eigenvector plotand archaeolgical data such as age and the office of minting.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1459-1462
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• 2007

In general a thermoelectric cooler (TEC) consists of a series of P type and N type thermoelectric materials sandwiched between two wafers. When a DC current passes through these materials, three different effects take place; Peltier effect, Joule heating effect and heat transfer by conduction due to temperature difference between hot and cold plates. In this study we have developed a micro TEC using $Bi_2Te_3$ (N type) and $Bi_{0.5}Sb_{1.5}Te_3$ (P type) thin films. In order to improve that performance of a micro TEC, we made 10 um height TE legs using special PR only for lift-off. We measured COP (coefficient of performance) and temperature difference between hot and cold connectors with current.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.289-289
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• 2007

Spinel structured $LiMn_2O_4$ is more economic and environmental friendly to be used as commercial active material for secondary battery compared to Co-oxide material active material, but spinel structure of $LiMn_2O_4$ is unstable and its capacitance decreases with increase of cycle. Therefore, the purpose of our sturdy is to improve the stability of $LiMn_2O_4$ spinel structure and increase its capacitance by using substituents or dopants. $LiMn_2O_4$ powder was synthesized by charging substituents or dopants mole fractions, and temperatures. Crystal state, structure and specific surface area of the synthesized powder were measured and also characteried electrochemically by measuring its impedance, charge-discharge capacitance and etc.

• Asian-Australasian Journal of Animal Sciences
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• 제30권3호
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• pp.379-385
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• 2017

Objective: This study was to examine in vivo digestibility, nitrogen balance and ruminal fermentation of tamarind (Tamarind indica) kernel powder extract residue (TKPER) compared to soybean products and by-products in wethers. Methods: Four wethers with initial body weight (BW) of $51.6{\pm}5.5kg$ were assigned in a $4{\times}4$ Latin square design to investigate nutritional characteristics of TKPER, dry heat soybean (SB), dry soybean curd residue (SBCR) and soybean meal (SBM) feeding with ryegrass straw (R) at a ratio of 1:1 at 2% of BW in dry matter (DM) on a daily basis. Results: The digestibility of DM, crude protein, and ether extract (EE) of TKPER-R diet were 57.0%, 87.0%, and 86.0%, respectively. Higher non-fiber carbohydrates digestibility was observed in TKPER-R diet (83.2%) than in SB-R diet (73.9%, p<0.05). Wethers fed the TKPER-R diet had lower retention of nitrogen (N) and ruminal ammonia nitrogen ($NH_3-N$) contents at 4 h after feeding than those fed the SBM-R diet (p<0.05), which had values similar to the SB-R or SBCR-R diet. The TKPER feeding had higher propionate (C3) and lower butyrate content, as well as lower acetate to propionate ratio (C2:C3) in rumen fluid than SBM feeding at 4 h after feeding (p<0.05). Conclusion: TKPER did not bring any side effect to the wethers although it was lack of fiber, and could be used as a high protein and energy ingredient in concentrate with appropriate roughage to meet the fiber requirement for ruminants.

• Bulletin of the Korean Chemical Society
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• 제15권11호
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• pp.961-966
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• 1994

Oligomerization of phenylacetylene is catalyzed by $Rh(ClO_4)(CO)(PPh_3)_2$ (Rh-1), $[Rh(CO)(PPh_3)_3]ClO_4$ (Rh-2), $[Rh(COD)L_2]ClO_4 (L_2=(PPh_3)_2$, Rh-3; $(PPh_3)(PhCN)$, Rh-4; $(PhCN)_2$, Rh-5), $[Rh(C_3H_5)(Cl)(CO)(SbPh_3)_2]ClO_4$ (Rh-6), $[Ir(COD)L_2]ClO_4 (L_2=(PPh_3)_2$, $Ir-1; (PPh_3)(PhCN)$, $Ir-2; (PhCN)_2$, Ir-3; (AsPh_3)(PhCN)$, $Ir-4; Ph_2PCH_2CH_2PPh_2$, Ir-5; COD, Ir-6 and 2,2'-dipyridyl, Ir-7), $Ir(ClO_4)(CO)(PPh_3)_2$, $Ir-8, [Ir(PhCN)(CO)(PPh_3)_2]ClO_4$, Ir-9 to produce dimerization products, 1,3-diphenylbut-1-yn-3-ene, 1, (E)-1,4-diphenylbut-1-yn-3-ene, 2 and (Z)-1,4-diphenylbut-1-yn-3-ene, 3, and cyclotrimerization products, 1,3,5-triphenylbenzene, 4 and 1,2,4-triphenylbenzene, 5. Product distribution of the oligomers varies depending on various factors such as the nature of catalysts, reaction temperature, counter anions and excess ligand present in the reaction mixtures. Increasing reaction temperature in general increases the yield of the cyclotrimerization products. Exclusive production of dimer 1 and trimer 4 can be obtained with Ir-1 at 0 $^{\circ}$C and with Ir-2 in the presence of excess PhCN (or $CH_3CN$) at 50 $^{\circ}$C, respectively. Dimer 2 (up to 81%) and trimer 5 (up to 98%) are selectively produced with Rh-1 at 50 and 100 $^{\circ}$C respectively. Production of 3 is selectively increased up to 85% by using $PF_6$- salt of $[Ir(COD)(PPh_3)_2]$+ at 25 $^{\circ}$C. Addition of $CH_3I$ to Rh-1 produces $CH_3PPh_3^+I-$ and increases the rate of oligomerization(disappearance of phenylacetylene). Among the metal compounds investigated in this study, Ir-1 catalyzes most rapidly the oligomerization where the catalytically active species seems to contain lr(PPh3)2 moiety. The stoichiometric reaction of phenylacetylene wth Ir-9 at 25 $^{\circ}$C quantitatively produces hydridophenyl-ethynyl iridium(III) complex, $[lr(H)(C{\equiv}CPh)(PhCN)(CO)(PPh_3)_2]ClO_4$ (Ir-11), which seems to be an intermediate for the oligomerization.

• 분석과학
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• 제20권1호
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• pp.33-40
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• 2007

대전시 3, 4 공단지역의 대기 중 미세분진을 대상으로 기기 중성자방사화분석법을 이용하여 유해금속을 포함한 약 27종의 미량원소를 분석하였다. 원소분석에 대한 정확도를 평가하기 위해 NIST SRM 2783(air particulate on filter media)을 사용하여 동일한 조건에서 분석한 결과, Sb, Mn, V, Mg, Na, K, Ti, Co, Zn, Sm은 상대오차 5% 이내의 매우 정확한 분석결과를 보였고 Cr, Fe, Ba, Th, Ce, Al, Cu는 10% 이내로 나타났다. 유해금속인 As, Mn, Se, V, Zn의 농도는 각각 $3.26{\pm}2.72$, $9.86{\pm}4.71$, $2.18{\pm}1.25$, $4.91{\pm}2.41$, $158{\pm}78ng/m^3$로 나타났고 인자분석 결과 연구대상지역의 미세분진에 대한 오염원은 6개로 추정되었다.

• 센서학회지
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• 제4권4호
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• pp.23-28
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• 1995

백금작업전극과 광가교화된 효소고정화막을 가진 ISFET 포도당 및 자당센서가 제조되었다. 효소반응의 부산물인 과산화수소수($H_{2}O_{2}$)는 백금전극표면에서 분해되어 센서의 감지특성을 개선시키고, 광가교화 고분자(PVA-SbQ)가 효소고정화막으로 이용되어 센서의 응답시간을 단축하였다. 그리고 백금전극의 면적변화에 따라 센서의 응답크기는 증가하였다. 센서의 응답시간은 $3{\sim}5$분이었으며, $30{\sim}300mg/dl$의 포도당 및 자당농도에서 센서의 선형적인 응답을 보였다.

• 대한환경공학회지
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• 제32권5호
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• pp.499-508
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• 2010

이 연구에서는 피해산정형 모델에 기초하여 제품 환경성 관련 정보를 국내 지리적, 환경적, 사회적 특성을 최대한 반영하여 '화폐가치'로 나타낼 수 있는 전과정 영향평가 지표를 제시하였다. 먼저 평가단계를 '특성화', '피해평가', 통합화의 3단계로 구분하였으며, 자원소비, 지구온난화, 오존층영향, 산성화, 부영양화 및 광화학산화물 생성의 6대 영향범주를 고려하였다. 아울러 6대 영향범주와 관련된 16개 범주별 종말점과 4대 보호대상에 대한 피해함수 및 피해계수를 도출하였다. 최종적으로 도출된 영향범주별 기준물질의 통합화 지수는 21.8원/kg Sb, 6.19원/kg $CO_2$, 53,000원/kg CFC-11, 13,100원/kg $SO_2$, 2,310원/kg ${PO_4}^{3-}$, 3,030원/kg $C_2H_4$로 나타났다. 이 연구결과를 활용하여 제품 전과정에 걸쳐 발생하는 환경부하가 보호대상에 미치는 영향을 화폐가치로 단일 지수화할 수 있으므로 도출되는 전과정 영향평가 결과의 이해도와 활용도를 높일 수 있다.