• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
• /
• pp.259-262
• /
• 1999

In this study, we investigated magnetic Properties of N $i_{0.2-x}$C $u_{x}$Z $n_{0.305}$F $e_{0.495}$ (x=0 ~0.2) ferrites. As the increased, the density and shrinkage increased until 5.3g/㎤, 20% respects, but the absorption decreased rate until 0.01%. As a results of the density, absorption rate, and shrinkage rate, the grain growth progressed rapidly in x=0.125 at 105$0^{\circ}C$, x=0.075 at 115$0^{\circ}C$, and x=0.025 at 115$0^{\circ}C$ for 3hours. As the CuO concentration increased, initial permeability increased at sintered 105$0^{\circ}C$ and 115$0^{\circ}C$ for 3 hours, but decreased at 125$0^{\circ}C$ for 3 hoers. The complex permeability as a function of frequency were high values at sintered 105$0^{\circ}C$ for 3 hours in x=0.005, 0.075.5.5.5.

• 센서학회지
• /
• 제22권5호
• /
• pp.327-332
• /
• 2013

Nickel oxide films using RF sputter was formed on the $SiO_2/Si$ substrate at the room temperature controlled with water circulation system. The feasibility of nickel oxide film as a bolometric material was demonstrated. GIXRD spectrum on NiO(111), NiO(200), and NiO(220) orientation expected as the main peaks were appeared in the grown nickel oxide films. The typical resistivity acquired at the RF power of 100W was about $34.25{\Omega}{\cdot}cm$. And it was reduced to $18.65{\Omega}{\cdot}cm$ according to the increase of the RF power to 400W. The TCR of fabricated micro-bolometer with the resistivity of $34.25{\Omega}{\cdot}cm$ was $-2.01%/^{\circ}C$. The characteristics of fabricated nickel oxide film and micro-bolometer were analyzed with XRD pattern, resistivity, TCR, and SEM images.

• 한국환경농학회지
• /
• 제22권2호
• /
• pp.118-123
• /
• 2003

본 연구는 서울 도심에 위치한 가로수 중에서 수령이 30년 이상 된 양버즘나무(Platanus occidentalis L.)와 은행나무(Ginkgo biloba L.)를 대상으로 토양 및 가로수의 연륜층별로 중금속 농도를 분석하여 이들 중금속이 가로수의 연륜 생장에 미치는 영향 정도를 비교 검토하였다. 가로수가 식재되어 있는 토양의 pH는 $6.62{\sim}8.01$이었으며, 중금속 평균농도는 Cr 0.63, Zn 109.03, Pb 26.49, Ni 1.98, Cu 44.98 mg/kg으로써 이 중 Zn, Pb, Cu의 농도는 일반 산림토양보다 높은 것으로 나타났다. 특히 금속 및 철물을 취급하는 상가가 밀집해 있고 차량통행이 많은 청계 2가 지역의 중금속 농토가 가장 높게 나타났다. 가로수의 연륜폭을 1979년부터 2000년까지 측정하여 회귀식으로 나타낸 결과, 두 수종 모두 감소하는 경향을 보였다. 또한, 토양 내 Cr, Pb, Cu의 농도는 양버즘나무의 최근 5년간 연륜층 내 Cr, Pb, Cu 농도와 양의 상관관계를 보였으며, 토양 내 Ni 농도는 은행나무의 연륜층 내 Ni 농도와 양의 상관관계를 보였다. 양버즘나무의 5년 단위 연륜층별 Cr 농도와 은행나무의 5년 단위 연륜층별 Ni, Cu 농도는 각각 연륜생장에 음의 상관관계를 나타냈다. 한편 서울지역의 연평균 기온, 강수량, 강수일수와 연륜폭의 연도별 변화 경향은 유사하였으나 통계적으로 유의성은 인정되지 않았다.

• 한국토양비료학회지
• /
• 제48권5호
• /
• pp.515-521
• /
• 2015

There is an increasing concern over heavy metal(loid) contamination of soil in agricultural areas including paddy soils. This study was conducted to monitor the background levels of heavy metal(loid)s, arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn) in major rice growing soils and its accumulation in brown rice in Korea. The samples were collected from 82 sites nationwide in the year 2012. The mean and range values of As, Cd, Cu, Hg, Ni, Pb, and Zn in paddy soils were 4.41 (0.16-18.9), 0.25 (0.04-0.82), 13.24 (3.46-27.8), 0.047 (0.01-0.20), 13.60 (3.78-35.0), 21.31 (8.47-36.7), and 54.10 $(19.19-103.0)mg\;kg^{-1}$, respectively. This result indicated that the heavy metal(loid) levels in all sampled paddy soils are within the permissible limits of the Korean Soil Environment Conservation Act. The mean and range values of As, Cd, Cu, Hg, Ni, Pb, and Zn in brown rice were 0.146 (0.04-0.38), 0.024 (0.003-0.141), 4.27 (1.26-16.98), 0.0024 (0.001-0.008), 0.345 (0.04-2.77), 0.113 (0.04-0.197), and 22.64 $(14.1-35.1)mg\;kg^{-1}$, respectively. The mean and range BCF (bioconcentration factor) values of As, Cd, Cu, Hg, Ni, Pb, and Zn in brown rice were 0.101 (0.01-0.91), 0.121 (0.01-0.70), 0.399 (0.05-2.60), 0.061 (0.016-0.180), 0.033 (0.004-0.44), 0.005 (0.003-0.013), and 0.473 (0.19-1.07), respectively, with Zn showing the highest. The results show that the levels of all metal(loid)s in all sampled brown rice are generally within the acceptable limit for human consumption.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
• /
• pp.30-32
• /
• 2005

The effects of mole ratio and Ti-ion on the dielectric properties and microstructure of modified $CaZrO_3$ composition such as $(Ca_{0.7}Sr_{0.3})_m(Ti_yZr_{1-y})O_3$ were investigated. Ti ions substituted on Zr-sites in these modified $CaZrO_3$ composition strongly affect the sintering density and microstructure of the fired ceramic body. With increasing the amount of Ti substituted on Zr-sites, the sintered density rapidly increased and the dense microstructures were obtained for the compositions having mole ratio of 1.01, whereas the sintered density and microstructures are nearly constant with the content of Ti-ion for the compositions having mole ratio of 0.99. With increasing the content of Ti ion, the curve of TCC (temperature coefficient of capacitance) as a function of temperature rotated clockwise and satisfied the COG characteristics for both of compositions with mole ratio of 0.99 and 1.01. The content of Ti ion seems to be more effective than mole with respect to the controlling of firing and TCC.

• 한국의류산업학회지
• /
• 제4권3호
• /
• pp.266-272
• /
• 2002

This research is compared and analyzed variations of the heavy metal contents in human hairs according to treating permanent wave manipulation before and after and permanent wave agents. This is the survey of women's hairs in 19 years old. On the basis of this we would like to analyze a extend of exposing of heavy metal scientifically. Also, we would to show a basic data for the permitted limits of heavy metal to keep the healthy hair The conclusion is as follows.; Mean contents of heavy metal in hairs is 2.11 ppm (Pb), 0.25 ppm (Cd), 2.62 ppm (Ni), 256 ppm (Zn), 8.45 ppm (Cu). In reducing agents (processing lotions) of perm, 1.50 ppm (Pb), 0.03 ppm (Cd), 0.05 ppm (Ni), 15.45 ppm (Zn), 0.86 ppm (Cu) in a perm (S), 2.30 ppm (Pb), 0.05 ppm (Cd), 0.05 ppm (Ni), 13.05 ppm (Zn), 0.65 ppm (Cu) in a perm (T). In oxidizing agents (neutralizer) of perm, 1.40 ppm (Pb), 0.03 ppm (Cd), 0.09 ppm (Ni), 9.05 ppm (Zn), 0.65 ppm (Cu) in a perm (S), 1.50 ppm (Pb), 0.02 ppm (Cd), 0.16 ppm (Ni), 8.00 ppm (Zn), 0.85 ppm (Cu) in a perm (T). Mean contents of lead(Pb) didn't show significant differences according to treating cysteine perm agents, showed it according to 3 treating thioglycolic acid perm agents (p<0.05). Mean contents of cadmium(Cd) showed significant differences (p<0.001) according to 2 treating both perm agents. Mean contents of nickel (Ni) showed neither. Mean contents of zinc (Zn) showed significant differences according to 2 treating cysteine perm agents (p<0.001) and 1 treating thioglycolic acid perm agents (p<0.01). Mean contents of copper (Cu) didn't show significant differences according to treating cysteine perm agents, showed it according to 1 treating thioglycolic acid perm agents (p<0.001).

• 대한지역사회영양학회지
• /
• 제5권2호
• /
• pp.289-296
• /
• 2000

The purpose of this study was to investigate the relationship and lipids in healthy adults on self-selected diets. These subjects consisted of 40 female college students residing in Chungnam. Anthropometric measure-ments, diet intake measurements, and blood collection were conducted. Serum concentrations of 5 microminerals(As, Cr, Mn, Se, Ni), lipids(triglyceride, total cholesterol, HDL-cholesterol), and glucose were measured by an ICP spectrometer and biochemical analyzer. The results were as follows. The mean age of the subjects was 22.34 years and the mean weight, height, and BMI were 52.89kg, 161.29cm and 20.34, respectively. The mean serum concentrations appeared to be 14.60ug/dl(As), 1.87ug/dl(Cr), 0.18ug/dl(Mn), 23.50ug/dl(Se), 0.21ug/dl(Ni), 60.73mg/dl(triglyceride), 138.49mg/dl(total cholesterol), 65.95mg/dl(HDL-cholesterol), 60.39mg/dl(LDL-cholesterol) and 88.82mg/dl(glucose). When analyzed by Pearson’s correlation coefficient, the serum concentration of Cr was negatively correlated with Ca and vitamin B12 intake(p〈0.05, p〈0.05) respectively, Mn was negatively correlated with Na intake(p〈0.05), Ni, however, was positively correlated with K intake(p〈0.05). The serum concentration of Se was positively correlated with LDL-cholesterol(p〈0.05), Ni, however, negatively correlated with total cholesterol, HDL-cholesterol, LDL-cholesterol, and glucose, respectively(p〈0.001, p〈0.01, p〈0.05). Further studies are needed to clarify the precise micromineral intakes, nutritional assessment of microminerals, and cause-effect relation of microminerals and serum lipids.

• 한국미생물·생명공학회지
• /
• 제36권2호
• /
• pp.165-172
• /
• 2008

본 연구에서는 분리균주 LH2를 이용하여 각각의 중금속 (Cr, Cu, Ni, Pb, Zn)에 대한 최적성장조건을 도출하였으며, pH, 온도 및 중금속 농도 변화에 따른 중금속 제거효율을 관찰하였다. 분리균주는 18S rDNA 분석에 의거하여 종 유사성이 100%로서 Exophiala sp.로 동정되었다. 분리균주의 경우 $25^{\circ}C$, pH 7인 진탕배양 조건에서 가장 높은 제거효율을 보였다. 첨가되는 중금속의 농도가 200 ppm이하일 경우 중 금속의 비제거속도를 구한 결과 pH 7인 조건에서 중금속의 종류와 무관하게 10 ppm에서 200 ppm으로 중금속의 농도가 증가함에 따라 0.01에서 4.43 mg-metal $L^{-1}{\cdot}d^{-1}{\cdot}mg^{-1}{\cdot}DCW^{-1}$으로 증가하였다. pH 7로 설정된 배양액에 약 200ppm의 중금속이 첨가될 경우 중금속의 제거효율은 Cr, Cu, Ni, Pb, 및 Zn 이 각각 99.28%, 97.67%, 91.94%, 99.77%, 99.61%로 관찰되었다.

• Korean Chemical Engineering Research
• /
• 제55권6호
• /
• pp.861-867
• /
• 2017

니켈 함량이 높은 리튬이차전지용 NCA 양극소재의 용량 및 수명특성을 향상시키기 위하여 붕소와 코발트를 상업용 $Li_{1.06}Ni_{0.91}Co_{0.08}Al_{0.01}O_2$ (NCA)에 도핑하여 리튬이차전지의 양극소재로 사용하였다. 상업용 NCA 양극소재는 약 $5{\mu}m$와 $12{\mu}m$ 크기의 2차 입자들이 혼합되어 있고 붕소와 코발트 도핑후 입자크기는 조금 감소되었다. 붕소와 코발트를 도핑한 NCA-B와 NCA-Co의 초기 방전용량은 각각 214 mAh/g과 200 mAh/g으로 도핑하지 않은 NCA에 비해 높게 나타났으며, 특히 NCA-Co는 20번째의 방전용량이 157 mAh/g으로 가장 우수한 방전용량특성을 나타내었다. 이는 코발트를 도핑함으로써 c축 방향으로의 결정이 성장되어 리튬이온의 확산이 용이하기 때문이다.

• 대한화학회지
• /
• 제35권5호
• /
• pp.512-519
• /
• 1991

유기용매$(CH_2Cl_2,\;C_6H_6,\;CH_3NO_2,\;(CH_3)_2CO,\;CHCl_3,\;DMF,\;DMSO)$에서 Zn(II)-, Cu(II)- 및 Ni(II)-tetrakis(o-chlorophenyl)porphyrin(o-ClTPP)과 Zn(II)-, Cu(II)- 및 Ni(II)-tetraphenylporphyrin(TPP) 착물과 질소원자를 포함한 염기성 리간드(pyridine, imidazole, 1-methylimidazole 및 2,6-lutidine)간의 결합 반응성을 이온강도 0.01M에서 연구하였다. metalloporphyrin과 염기성 리간드간의 평형상수는 온도범위 15 ~ 35${\circ}C$에서 분광광도법을 이용하여 결정하였으며, 이 때 M(II)-TPP에서 관찰된 평형상수는 입체적 장애가 더 큰 M(II)-(o-Cl)TPP에서 보다 큰 값을 나타내었다. M(II)-TPP에서 logK값은 염기성 리간드의 pKa값이 커질수록 증가하였지만 입체적장애를 받는 M(II)-(o-Cl)TPP에서 logK는 리간드의 $pK_a$값에 비례하지 않았다. 열역학적 파라미터 분석결과 M(o-Cl)TPP의 안정도는 거의 반응엔트로피에 의존하였으나, M(II)-TPPL의 안정도는 반응엔탈피와 반응엔트로피에 거의 비슷한 영향을 나타내었다. metalloporphyrin에 대한 용매의 배위능을 DMF, DMSO, $CHCl_3,\;(CH_3)_2CO$에서 측정하였고, 이들 결과로부터 평형상수에 대한 용매효과를 논의하였다.