• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.93-99
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• 2001

This study aims at finding out pertinent reaction conditions for treating high concentration ammonia contained in N-chemical factory wastewater with decompressed ammonia stripping method that was designed. And it also tries to investigate adsorption capability of removed ammonia to soil. The results from experiments are as follows ; 1. The removal rate of N $H_3$-N of synthetic wastewater was under 85% at pH 10 with decompressed ammonia stripping method. The reaction time in pressure 360 mmHg at pH 11 and 12 was shorter than in 460 mmHg, and the removal rate of N $H_3$-N with decompressed ammonia stripping method at 9$0^{\circ}C$ was 11~15% higher than air stripping 2. The optimum conditions for decompressed ammonia stripping with synthetic sample were shown as pH 12, temperature 9$0^{\circ}C$, internal reaction pressure 460 mmHg and reaction time 50 minutes. These conditions were applied to treat the wastewater containing organic-N 290.5mg/$\ell$, N $H_3$-N 168.9mg/$\ell$, N $O_2$-N 23.2mg/$\ell$, N $O_3$-N 252.4mg/$\ell$, T-N 735mg/$\ell$. Organic-N turned out to be removed 60%, the removal rate of N $H_3$-N IS 94%, T-N is 50%. But N $O_2$-N and N $O_3$-N were increased with 7.8% and 14.9% respectively. 3. The CO $D_{Sr}$ removal rate in decompressed ammonia stripping reaction was 42% and S $O_4$$^{2-}$ was removed 8.2%. It was turned out caused with higher pH and thermolysis. 4. In soil adsorption of ammonia desorbed from the decompressed stripping process of wastewater, the recovery rate was 76% in wet soil.

• Kyungpook Mathematical Journal
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• v.50 no.2
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• pp.177-193
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• 2010

Working with the various special functions of mathematical physics and applied mathematics we often encounter inverse relations of the type $F_n(x)=\sum\limits_{k=0}^{n}A^n_kG_k(x)$ and $ G_n(x)=\sum\limits_{k=0}^{n}B_k^nF_k(x)$, where 0, 1, 2,$\cdots$. Here $F_n(x)$, $G_n(x)$ denote special polynomial functions, and $A_k^n$, $B_k^n$ denote coefficients found by use of the orthogonal properties of $F_n(x)$ and $G_n(x)$, or by skillful series manipulations. Typically $G_n(x)=x^n$ and $F_n(x)=P_n(x)$, the n-th Legendre polynomial. We give a collection of inverse series pairs of the type $f(n)=\sum\limits_{k=0}^{n}A_k^ng(k)$ if and only if $g(n)=\sum\limits_{k=0}^{n}B_k^nf(k)$, each pair being based on some reasonably well-known special function. We also state and prove an interesting generalization of a theorem of Rainville in this form.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.21-21
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• 1997

• YAKHAK HOEJI
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• v.39 no.5
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• pp.569-571
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• 1995

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.758-760
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• 2001

• Korean Journal of Mathematics
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• v.25 no.3
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• pp.349-358
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• 2017

The cyclic group $C_n={\langle}(12{\cdots}n){\rangle}$ acts on the set $(^{[n]}_k)$ of all k-subsets of [n]. In this action of $C_n$ the number of orbits of size d, for d | n, is $$O^{n,k}_d={\frac{1}{d}}{\sum\limits_{{\frac{n}{d}}{\mid}s{\mid}n}}{\mu}({\frac{ds}{n}})(^{n/s}_{k/s})$$. Stanton and White [6] generalized the above identity to construct the orbit polynomials $$O^{n,k}_d(q)={\frac{1}{[d]_{q^{n/d}}}}{\sum\limits_{{\frac{n}{d}}{\mid}s{\mid}n}}{\mu}({\frac{ds}{n}})[^{n/s}_{k/s}]_{q^s}$$ and conjectured that $O^{n,k}_d(q)$ have non-negative coefficients. In this paper we give a constructive proof for the positivity of coefficients of the orbit polynomial $O^{n,2}_d(q)$.

• Honam Mathematical Journal
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• v.30 no.2
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• pp.233-246
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• 2008

In this paper, we obtain the general solution of the following cubic type functional equation and establish the stability of this equation (0.1) $kf({{\sum}\limits^{n-1}_{j=1}}x_j+kx_n)+kf({{\sum}\limits^{n-1}_{j=1}}x_j-kx_n)+2{{\sum}\limits^{n-1}_{j=1}}f(kx_j)+(k^3-1)(n-1)[f(x_1)+f(-x_1)]=2kf({\sum\limits^{n-1}_{j=1}}x_j)=K^3{\sum\limits^{n-1}_{j=1}[f(x_j+x_n)+f(x_j-x_n)]$ for any integers k and n with k ${\geq}$ 2 and n ${\geq}$ 3.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.269-278
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• 1991

Fine AlN powder was synthesized by carbothermal reduction and nitridation of alumimun hydroxide prepared from Al-isopropoxide. AlN ceramics with Y2O3 and CaO were prepared by hot-pressing under the pressure of 30 MPa at 180$0^{\circ}C$ for 1 h in N2 atmosphere. Grain boundary behavior and purification mechanism of AlN lattice were examined by heat treatment of AlN ceramics at 185$0^{\circ}C$ for 1-6 h in N2 atmosphere. AlN ceramics without sintering additives showed poor sinterability. However, Y2O3-doped and CaO-doped AlN ceramics were fully densified nearly to theoretical density. As the heat treatment time increased, c-axis lattice parameter increased. This is attributed to the removal of Al2O3 in AlN lattice. This purification effect of AlN attice depended upon the quantity of secondary oxide phase in the inintial stage of heat treatment and the heat treatment time.

• Journal of the Semiconductor & Display Technology
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• v.3 no.2
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• pp.17-21
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• 2004

Aluminum nitride(AlN) thin films were deposited on silicon substrate by reactive RF magnetron sputtering without substrate heating. We investigated the dependence of some properties for AlN thin film on sputtering conditions such as working pressure, $N_2$ concentration and RF power. XRD, Ellipsometer and AES has been measured to find out structural properties and preferred orientation of AlN thin films. Deposition rate of AlN thin film was increased with an increase of RF power and decreased with an increase of $N_2$ concentration. AES in-depth measurements showed that stoichiometry of Aluminium and Nitrogen elements were not affected by $N_2$ concentration. It has shown that low working pressure, low $N_2$ concentration and high RF power should be maintained to deposit AlN thin film with a high degree of (0002) preferred orientation.

• Communications of the Korean Mathematical Society
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• v.39 no.2
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• pp.331-343
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• 2024

Let ℜ be a *-algebra with unity I and a nontrivial projection P₁. In this paper, we show that under certain restrictions if a map ψ : ℜ → ℜ satisfies $$\Psi(S_1{\diamond}S_2{\cdot}{\cdot}{\cdot}{\diamond}S_{n-1}{\bullet}S_n)=\sum_{k=1}^nS_1{\diamond}S_2{\diamond}{\cdot}{\cdot}{\cdot}{\diamond}S_{k-1}{\diamond}{\Psi}(S_k){\diamond}S_{k+1}{\diamond}{\cdot}{\cdot}{\cdot}{\diamond}S_{n-1}{\bullet}S_n$$ for all S_n-2, S_n-1, S_n ∈ ℜ and S_i = I for all i ∈ {1, 2, . . . , n - 3}, where n ≥ 3, then ψ is an additive *-derivation.