• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1439-1444
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• 2006

A $Cu^{2+}$ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff,s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl)ethylidene]hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of $1.0\;{\times}\;10^{-5}-1.0\;{\times}\;10^{-11}$ M of $Cu^{2+}$. The microelectrode exhibits a nice Nernstian slope of 25.9 ${\pm}$ 0.3 mV $decade^{-1}$ in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges ($\sim$5 s). The detection limit of proposed sensor is $5.0\;{\times}\;10^{-12}$ M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of $Cu^{2+}$ with EDTA. The proposed membrane electrode was used for the direct determining of $Cu^{2+}$ content in black and red pepper, and in waste water samples.

• Korean Journal of Mathematics
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• v.17 no.1
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• pp.83-90
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• 2009

In this paper, we investigate isomorphisms between $C^*$-ternary algebras and derivations on $C^*$-ternary algebras associated with the Cauchy-Jensen functional equation $$2f(\frac{x+y}{2}+z)=f(x)+f(y)+2f(z)$$, which was introduced and investigated by Baak in [2].

• Journal of the Korean Ceramic Society
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• v.21 no.1
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• pp.5-10
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• 1984

$eta$-Sialon synthesis was investigated via the simulataneous reduction and nitriding of Wando pyrophyllite. When Wando pyrophyllite-graphite-$Si_3N_4$ seed mixture was heated at 135$0^{\circ}C$ for as long as 10 hours in 80% $N_2$-20%$H_2$ atomsphere $eta$-$Si_3N_4$ solid solution was mainly formed together with a small amount of $\alpha$-$Si_3N_4$ The value z of the forming $Si_{6-x}Al_2O_2N{8-z}$ was decreased with heating time.

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.32-32
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• 2002

• YAKHAK HOEJI
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• v.30 no.2
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• pp.100-103
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• 1986

The second derivative absorption spectra of acetaminophen in commercial tablet forms were measured without prior separation from other pharmaceutical adjuvants. The second derivative spectra of acetaminophen were found to have no influence on the characteristic absorbance band of it. A plot of 25 sets of the ordinate (Z) values with various acetaminophen concentrations mixed in other additives gave a straight line (correlation coefficient, 0.9999) and the slope was 2.901${\times}10^{-2}Z$ value/($\mu\textrm{g}$/ml). The procedures were sufficiently sensitive, precise and economical for the assay of tablets of acetaminophen.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.39-40
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• 1996

Using the Keck 10 m telescope data with the HIRES spectrograph, we analyzed the evolution of Lyman$\alpha$ forest clouds at z > 2 down to the HI column density $10^{12.8}cm^{-2}$. The number density per unit column density does not change with redshifts at lower HI cloumn density ($N_{HI} < 10^{14}cm^{-2}$), while the forest clouds at higher column density disappear rapidly. The cutoff b value, the thermal temperature indicator, increases as redshift decreases. The correlation strength seems to be stronger as redshift decreases.

• Kyungpook Mathematical Journal
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• v.45 no.2
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• pp.241-247
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• 2005

Let ${\gamma}{\equiv}\left{{\gamma}_{ij}\right}(0{\leq}i+j{\leq}2n)$ be a collection of complex numbers with ${\gamma}_{00}>0$ and ${\gamma}_{ji}={\bar{\gamma}}_{ij}$. The truncated complex moment problem for ${\gamma}$ entails finding a positive Borel measure ${\mu}$ supported in the complex plane ${\mathbb{C}}$ such that ${\gamma}_{ij}={\int}{\bar{z}}^{i}z^jd{\mu}(z)(0{\leq}i+j{\leq}2n)$. We solve this truncated moment problem with data in a circle and discuss the behavior of data in an extended moment matrix.

• Honam Mathematical Journal
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• v.19 no.1
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• pp.97-105
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• 1997

Let $R_k({\alpha})$, $0{\leq}{\alpha}<1$, $k{\geq}2$ denote certain subclasses of analytic functions in the unit disc E with bounded radius rotation. A function f, analytic in E and given by $f(z)=z+{\sum_{m=2}^{\infty}}a_m{z^m}$, is said to be in the family $R_k(n,{\alpha})n{\in}N_o=\{0,1,2,{\cdots}\}$ and * denotes the Hadamard product. The classes $R_k(n,{\alpha})$ are investigated and same properties are given. It is shown that $R_k(n+1,{\alpha}){\subset}R_k(n,{\alpha})$ for each n. Some integral operators defined on $R_k(n,{\alpha})$ are also studied.

• Journal of the Korean Ceramic Society
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• v.34 no.9
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• pp.941-948
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• 1997

CuCl nanocrystallites dispersed nonlinear optical silica and borosilicate glasses were fabricated by sol-gel process. CuCl powder was dissolved in TEOS(Si(OC2H5)4) and TMB((CH3O)3B), precursors of silica and borosilicate glasses, with ethanol, water and HCl, and precipitated through the heat treatment in the matrix glass. The optical properties of CuCl doped glasses were measured using the spectrophotometer at room temperature and low temperature(77K); Z1, 2 and Z3 exciton peaks from the absorption spectra, were observed at about 370 nm and 380 nm, respectively. The average radius of nanocrystallites, calculated from the blue shift of Z3 excitons, was measured according to annealing temperature and time. The precipitation temperature of CuCl nanocrystallites was decreased when boron was added to silica glass. Increase of annealing temperature and time made average radius of nanocrystallites saturated about 2 nm.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.53.2-53.2
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• 2013

외부 고리를 갖는 은하들(Outer ring galaxies)을 SDSS dr7 목록에서 분류하여, 이들이 갖는 특징과 링 구조(Ring structure)를 형성하는데 외부환경의 요인이 있는지 조사하고자 했다. z<0.05, b/a>0.6, R>6"의 조건에서 25,308개의 은하들을 추출하였고, SDSS image tool을 이용하여 531개의 외부 고리 은하(Outer ring galaxies)또는 외부고리를 갖고 있는 것처럼 보이는 은하(Ring-like galaxies)를 육안으로 분류하였다. 5개(u, g, r, i, z)의 필터로 관측되어진 CCD 이미지의 분석으로 최종적으로 69개의 외부고리 은하(Outer ring galaxies)를 선정하였다. 통계적으로 전체 은하에서 외부 고리 은하가 차지하는 비율이 약 0.2726%라는 결과를 얻게 되었고, 은하들의 주변의 환경을 조사한 결과 배경밀도와 비리얼 반경에 있어서 다른 형태의 고리를 갖고 있는 은하들과의 유의미한 특이점은 보이지 않았다.