• 환경위생공학
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• 제19권4호
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• pp.9-18
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• 2004

In this study, the observation data for the yellow sandy dust phenomena from the year 1999 to 2003 at background sites in Korea were collected at Global Atmospheric Observatory at An-Myeon island and its temporal variation were analyzed. The chemical characteristics of the fine particles were also analyzed in order to evaluate sources of the yellow sandy dust particles. The results showed that the monthly average mass concentration of the fine particles was the highest in springtime and the lowest in summertime in general. The magnitude of its variation was also the highest in March in which the occurrence of yellow sandy dust was the most frequent and thus the number of samples was the largest, while the lowest in June through September. The yearly variation of ion components contributions to the total mass concentration of the fine particles was slowly decreasing, showing that $63\%$ in 1999, $59\%$ in 2000 and $56\%$ in 2003. The most prevalent ion components in the fine particles were found to be $NO_3$ and $SO_4^{2-}$, which are known to be source materials of acidic precipitation, and $NH_4^+$, a neutralizing material of the acid precipitation. Relative proportion of metal components in the fine particles was calculated as $14\%$ in average, and their concentrations are in an order of Fe > Al > Na > Ca > Zn > Pb > Cu > Mn > Ni > Cd > Cr > Co > U. The results indicated that main sources of the metals was soil-originated Fe, Al, Ca, and Mg, and the contribution of anthropogenic air Pollution-originated Zn, Pb, Cu, Mn were also high and keep slightly increasing. Statistical analysis showed that the chemical components could be divided into soil-originated group of Mg, Al, Ca, Fe, and Mn and air pollution-originated group of $NO_3$, Zn, Pb, and they are occupying more than $60\%$of all the components in the dusty sand. The results explain that An-Myeon island is more influenced by soil-originated source than ocean-originated one and also the influencing strength of anthropogenic poilution-originated source is less than $50\%$ of that of soil-originated sources. Compared to non-yellow sandy period, the yellow sandy dust period showed that the amounts of soil-originated $Mg^{2+}$ and $Ca^{2+}$ and ocean-originated $Na^+$ and $Cl^-$ were increased to more than double and the metals of Mg, Al, Ca, Fe were also highly increased, while micro metal components such as Pb, Cd, Zn, which have a tendency of concentrating in air, were either decreased or maintained at nearly constant level. In the period of yellow sandy dust, a strong positive correlation was observed between water soluble ions and between metals in terms of its concentration, respectively. Factor analysis showed that the first group being comprised of about $43\%$ of the total inorganic components was affected by soil and they are ions of $Na^+,\;Mg^{2+}\;and\;Ca^{2+}$ and metals of Na, Fe, Mn and Ni. The result also showed that the metals of Mg and Cr were classified as second group and they were also highly affected by soil sources.

• 한국토양비료학회지
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• 제39권2호
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• pp.86-94
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• 2006

우리나라 고품질 완전미의 안전생산을 위한 적정 질소시비량을 설정하기 위하여 2003-2004년에 전국 24 농가포장을 대상으로 논토양 유형별로 재배시험을 수행하였다. 토양유형별 쌀 수량, 완전미 수량 및 단백질 함량은 질소시비수준이 증가할 수록 많아지는 경향이고, 토양유형별 완전미 비율 및 Toyo 식미치는 질소시비수준이 증가하면 오히려 낮아지는 경향을 보였다. 지역별로 본 수확기 실물체와 쌀의T-N 함량과 단백질함량도 질소 시비량 증가로 많아지는 반면, Mg/K 당량비는 오히려 질소 감비로 증가하는 경향이었다. 고품질미의 안전생산을 위하여 하향 조정된 논토양 유형별 질소의 적정시비량은 ha당 보통논, 사질논, 고논 80-100 kg(89 kg), 미숙논 90-110 kg (100 kg), 염해논(숙답) 100-130 kg(112 kg) 이었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.211-211
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• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.

• 대한화학회지
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• 제33권4호
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• pp.366-370
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• 1989

새로운 거대고리 리간드 1,15,18-triaza-3,4 : 12,13-dibenzo-5,8,11-trioxa-cycloeicosane(NdienOdien$H_4$=$N_3O_3$)를 합성하여 $25^{\circ}C$ 95% 메탄올 용액에서 전위차계를 이용하여 양성자 첨가반응의 평형상수를 구한 결과 log $K_1$ ; log $K_2$ ; log $K_3$는 9.1; 8.1; 3.6이었다. 또한 위의 리간드와 이미 합성된 리간드 1,12,15-triaza-3,4;9,10-dibenzo-5,8-dioxa-cycloheptadecane(NdienOen$H_4$=$N_3O_2$)를 각각 Ni(II), Cu(II)의 금속이온과의 착물을 합성하여 수용액에서 산을 가해 착물의 산해리반응 속도 상수를 여러온도에서 분광광도법으로 측정하였다. 또한 활성화에너지($E_a$)와 활성화파라메타 ${\Delta}H^{\neq}$, ${\Delta}S^{\neq}$를 구하였다. 그리고 이들의 자료로부터 이 반응계의 타당한 해리메카니즘을 제안하였다.

• 한국대기환경학회지
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• 제27권6호
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• pp.711-722
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• 2011

This study is aimed to estimate the $PM_{2.5}$ source apportionment at Seoul intensive monitoring site located in Seoul metropolitan area. Time-resolved chemical compositions of $PM_{2.5}$ are measured in real time using ambient ion monitor, semi-continuous carbon monitor, and on-line XRF at Seoul intensive monitoring site in 2010. The mass concentration of $PM_{2.5}$ was simultaneously monitored with eight ionic species (${SO_4}^{2-}$, $NO_3{^-}$, $Cl^-$, $NH_4{^+}$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$), two carbonaceous species (OC and EC), and fourteen elements (Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Pb) in 1-hr interval. The data sets were then analyzed using EPA PMF version 3 to identify sources and contributions to $PM_{2.5}$ mass. EPA PMF modeling identified eight PM2.5 sources, including soil dust, secondary sulfate, secondary nitrate, motor vehicle, coal combustion, oil combustion, biomass burning, and municipal incineration. This study found that the average $PM_{2.5}$ mass was apportioned to anthropogenic sources such as motor vehicle, fuel combustion, and biomass burning (61%) and secondary aerosols, including sulfate and nitrate (38%).

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.81.2-81.2
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• 2012

To fabricate a metal mold for injection molding, hot-embossing and imprinting process, mechanical machining, electro discharge machining (EDM), electrochemical machining (ECM), laser process and wet etching ($FeCl_3$ process) have been widely used. However it is hard to get precise structure with these processes. Electrochemical etching has been also employed to fabricate a micro structure in metal mold. A through mask electrochemical micro machining (TMEMM) is one of the electrochemical etching processes which can obtain finely precise structure. In this process, many parameters such as current density, process time, temperature of electrolyte and distance between electrodes should be controlled. Therefore, it is difficult to predict the result because it has low reliability and reproducibility. To improve it, we investigated this process numerically and experimentally. To search the relation between processing parameters and the results, we used finite element simulation and the commercial finite element method (FEM) software ANSYS was used to analyze the electric field. In this study, it was supposed that the anodic dissolution process is predicted depending on the current density which is one of major parameters with finite element method. In experiment, we used stainless steel (SS304) substrate with various sized square and circular array patterns as an anode and copper (Cu) plate as a cathode. A mixture of $H_2SO_4$, $H_3PO_4$ and DIW was used as an electrolyte. After electrochemical etching process, we compared the results of experiment and simulation. As a result, we got the current distribution in the electrolyte and line profile of current density of the patterns from simulation. And etching profile and surface morphologies were characterized by 3D-profiler(${\mu}$-surf, Nanofocus, Germany) and FE-SEM(S-4800, Hitachi, Japan) measurement. From comparison of these data, it was confirmed that current distribution and line profile of the patterns from simulation are similar to surface morphology and etching profile of the sample from the process, respectively. Then we concluded that current density is more concentrated at the edge of pattern and the depth of etched area is proportional to current density.

• 자원환경지질
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• 제43권1호
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• pp.43-52
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• 2010

충북 옥천 지역 천부지하수의 지화학적 특성과 질산염의 기원을 규명하기 위하여 지화학 및 질소동위원소 연구가 수행되었다. 지하수의 pH는 6.9~8.4로 중성 내지 약알칼리성으로 나타났다. 지하수의 전기전도도, 산화환원전위 및 용존산소량은 각각 $344.2\;{\mu}s/cm$, 195 mV, 4 mg/L이다. 채취된 45개의 시료에서 검출되어진 질산성 질소의 농도는 12.4 mg/l~34.2 mg/l 범위를 보이며, 모두 먹는물 수질기준의 10 mg/l를 초과하는 것으로 나타났다. 질산성 질소의 동위원소 분석 결과, $\delta^{15}N-NO_3$는 $2.7^{\circ}/_{\circ\circ}{\sim}18.8^{\circ}/_{\circ\circ}$이다. 이와 같이 지하수내 15N의 부화는 질산성질소의 오염기원이 동물분뇨임을 지시한다. 또한 일부는 탈질화작용이 기여한 것으로 보여진다.

• 한국식품위생안전성학회지
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• 제13권2호
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• pp.155-163
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• 1998

본 연구는 정상 성인에서 관상동맥질환의 위험인자로 알려진 혈액내 Lipoprotein(a) 농도의 실태를 파악하고 이들 농도와 지질 농도, 섬유소원, 공복혈당 및 일상생활요인과의 관계를 알아보고자 수행되었다. 연구대상은 서울지역 일부 초, 중, 고교 교사들로 의료보험 관리 공단의 신검에서 건강상태가 양호하다고 판정 받은 남자 80명, 여자 60명을 대상으로 혈액분석과 설문 조사를 1996년 11월 2일부터 11월 7일에 걸쳐 실시하였다. 혈액 분석 결과에 따라 이들을 정상군과 위험군으로 나누고 이들 군들 사이에서 Lipoprotein(a) 농도와의 연관성을 알아보았다. 결과는 다음과 같다. 1. 전체 대상자들 중 관상동맥질환 유발의 위험수준인 30mg/dL을 초과하는 대상자는 140명중 37명으로 26.4%에 달했다. 대상자들의 Lipoprotein(a) 평균 농도는 남자는 $16.94{\pm}12.70\;mg/dL$, 여자는 $17.92{\pm}17.58\;mg/dL$로 성별간의 유의한 차이는 없었다. 2. 대상자의 연령에 따른 Lipoprotein(a) 농도의 경우 연령간의 유의한 차이를 보였다(p<0.05). 3. 대상자의 혈액을 분석하여 각 항목에 대해 정상군과 위험군으로 나눈 후 Lipoprotein(a) 농도와 각 항목들간의 유의성을 살펴 본 결과 1) Aspartate aminotransferase, Alanine amiontransferas와 Lipoprotein(a)농도 사이에는 유의한 차이가 나타나지 않았다. 2) 공복 혈당, 섬유소원과 Lipoprotein(a) 농도 사이에도 유의한 차이가 관찰되지 않았다. 3) 지질농도(총콜레스테롤, 고비중 지단백 콜레스테롤, 저비중 지단백 콜레스테롤 , 중성지방)와 Lipoprotein(a) 농도 사이에도 유의한 차이가 발견되지 않았다. 4) 일상생활요인과 Lipoprotein(a) 농도와의 경우 혈압, 비만도, 성별, 흡연 등에서는 유의한 차이가 나타나지 않았다. 그러나 육식 섭취, 음주, 염분 섭취의 정도에 따라서 이들과 Lipoprotein(a) 농도 사이에 유의한 차이가 있는 것으로 나타났다(p<0.05). 5) 혈액 분석 결과와 일상생활요소를 모두 통털어 Lipoprotein(a) 농도가 고려된 경우 나이와 육식섭취의 정도에 따라 정상군과 위험군에서 유의한 차이가 관찰되었다. (p<0.05, p<0.01).

• 미생물학회지
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• 제26권3호
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• pp.215-222
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• 1988

광합성 세균인 Rhodopsedomonas sphaeroides의 질소 고정 효소 활성에 미치는 암모니아와 glutamine의 영향을 조사하였다. 그 결과 RP. sphaeroides의 질소 고정 효소 활성은 암모니아와 glutamine에 의해 저해를 받았으며, 이들의 저해는 암모니아와 glutamine이 다 사용된 후에는 질소 고정 효소의 활성이 되살아나는 가역적인 반응이었다. glutamine synthetase의 활성을 비가역적으로 저해하는 methionine sulfoximine (MSX)를 사용하여 암모니아와 glutamine이 직접 질소 고정 효소의 활성을 저해하는지를 일아보았다. 암모니아에 의한 질소 고정 효소의 switch-off에 미치는 MSX의 영향은 균의 배양 시기에 의존함을 알 수 있었다 . 12시간 배양한 경우, $500{\mu}M$ NH,Cl에 의해 질소 고정 효소는 저해를 받았으며, $500{\mu}M$의 MSX를 주가로 처리하였을 경우, GS는 21% 저해를 받았으며, 이때 유리된 암모니아의 량은 감소하였고, 질소 고정 효소의 활성은 회복되지 않았다. 그러나 20시간 배양한 경우, $500{\mu}M$ NH,CI을 처리한 후 $100{\mu}M$ MSX플 첨가하면, GS의 활성은 완전히 저해되고, 유리된 암모니아의 량은 약간 증가하였으나 질소 고정 효소의 활성의 저해는 MSX에 의해 회복되었다. 따라서 Rp. sphaeroides의 경우, in vivo 상태에서 암모니아에 의한 질소 고정 효소의 활성 저해는 암모니아 자체에 의한 것이 아니라 암모니아 동화산물에 의한 것임을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.378-384
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• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.