• 한국광물학회지
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• 제15권1호
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• pp.78-84
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• 2002

New pyrochlore-type phases($A_2$$B_2$$O_{7}$) were synthesized in the systems: CaO-C$eO_2$-T$iO_2$, CaO-$UO_2$(T$hO_2$)-Z$rO_2$, CaO-$UO_2$(T$hO_2$)-$Gd_2$$O_3$-T$iO_2$-Z$rO_2$, 및 CaO-T$hO_2$-S$nO_2$. The starting materials were pressed with the pressure of 200~400 MPa and sintered at 1500~ 155$0^{\circ}C$ for 4~8 hours in air and at 1300~ 135$0^{\circ}C$ for 5 ~50 hours under oxygen atmosphere. The products were characterized using XRD, SEM/EDS and TEM. In the bulk compositions of CaCe$Ti_2$$O_{7}$, CaTh$Zr_2$$O_{7}$,($Ca_{0.5}$ Gd$Th_{0.5}$)(ZrTi)$O_{7}$) ($Ca_{0.5}$Gd$Th_{0.5}$)(ZrTi)$O_{7}$, ($Ca_{0.5}$G$dU_{0.5}$)(ZrTi)$O_{7}$ and CaTh$Sn_2$$O_{7}$ , pyrochlore was the major phase, together with other oxide phase $of_2$$O_{7}$ fluorite structure. In the samples with target compositions CaU$Zr_2$$O_2$및 $Ca_{0.5}$ G$dU_{0.5}$)$Zr_2$T$iO_{7}$ pyrochlore was not identified, but a fluorite-structured phase was detected. The formation factor as the stable phase depended on crystal chemical characteristics of the actinide and lanthanide elements of the system concerned.

• 한국대기환경학회지
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• 제13권5호
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• pp.333-343
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• 1997

The cyclone/annular denuder system/filter pack sampling system (ADS) was used to collect the acidic air pollutants in Chongju city. The data set was collected on fifty -eight different days with 24 hour sampling period from October 27, 1995 through August 25, 1996. The chemical species measured were HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas phase, and PM2.5( $d_{p}$ ＜2.5 ${\mu}{\textrm}{m}$), S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ and N $H_4$$^{+}$ in the Particulate Phase. Mean concentrations measured for this study were: 0.45 $\mu\textrm{g}$/㎥ for HN $O_3$, 3.39 $\mu\textrm{g}$/㎥ for HN $O_2$, 26.4 $\mu\textrm{g}$/㎥ for S $O_2$, 3.83$\mu\textrm{g}$/㎥ for N $H_3$, 44.2 $\mu\textrm{g}$/㎥ for P $M_{2.5}$, 8.22 $\mu\textrm{g}$/㎥ for S $O_4$$^{2-}$, 3.63 $\mu\textrm{g}$/㎥ for N $O_3$$^{[-10]}$ , and 2.84 $\mu\textrm{g}$/㎥ for N $H_4$$^{- }$. HN $O_3$ and N $H_3$ were higher during the summer. However, HN $O_2$ and S $O_2$ were higher during the fall and winter. P $M_{2.5}$ , S $O_4$/ sup 2-/ and N $H_4$$^{+}$ were not showed seasonal variations, but N $O_3$$^{[-10]}$ was higher in the winter.ter.r.

• 한국세라믹학회지
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• 제38권4호
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• pp.308-313
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• 2001

We report the effects of the V$_2$O$_{5}$ additive on the sintering behavior and microwave dielectric properties of ZnNb$_2$O$_{6}$ ceramics. Densification temperatures of V$_2$O$_{5}$-doped ZnNb$_2$O$_{6}$ samples are lowered to the range of 875-9$25^{\circ}C$ because of the liquid phase sintering. Doped samples are composed of a Zn(Nb,V)$_2$O$_{6}$ solid solution and second phases. Up to 5 wt% V$_2$O$_{5}$ is the only second phase, however, V$_2$O$_{5}$ also exists as the second phase for 10 wt% V$_2$O$_{5}$ addition. In comparison with reported values of undoped ZnNb$_2$O$_{6}$ ceramics, microwave properties of V$_2$O$_{5}$-doped ZnNb$_2$O$_{6}$ samples are seriously degraded, which is confirmed to originate from the second phases. The optimum microwave properties (Q$\times$f=13,800, $\varepsilon$$_{r}$=23, $\tau$$_{f}$=-66ppm/$^{\circ}C$) are obtained from ZnNb$_2$O$_{6}$ with the addition of 5 wt% V$_2$O$_{5}$ sintered at 90$0^{\circ}C$.90$0^{\circ}C$.EX>.

• 한국세라믹학회지
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• 제35권10호
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• pp.1107-1112
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• 1998

We could obtan c-axis oriented $SrBi_2$$Ta_2$$O_9$ thin films on usual Pt(111)/Ti/$SiO_2$/Si(100) substrate using a r. f. magnetron sputtering technique. According to the increase of sputtering pressure from 250 to 300 mTorr the Bi content and degree of the c-a xis preferred orientation of $SrBi_2$$Ta_2$$O_9$ thin films were increased. By controlling Bi(or $Bi_2O_3$) loss from $SrBi_2$$Ta_2$$O_9$ thin films during post annealing and by inserting $Bi_2O_3$ layer in $SrBi_2$$Ta_2$$O_9$ thin films the effect of Bi content on the c-axis oriented growth of $SrBi_2$$Ta_2$$O_9$ thin films could be investigated without the effect of sputtering pressure. The degree of the c-axis preferred orientation of $SrBi_2$$Ta_2$$O_9$ thin films was increased with increasing with increasing Bi content by control of Bi(or $Bi_2O_3$) loss of $SrBi_2$$Ta_2$$O_9$ thin films. But the c-axis oriented growth of $SrBi_2$$Ta_2$$O_9$ thin films disappeared by the inserting of $Bi_2O_3$ lay-er in $SrBi_2$$Ta_2$$O_9$ thin films.

• Animal Systematics, Evolution and Diversity
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• 제28권2호
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• pp.105-116
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• 2012

Based on samples collected from the Korean Exclusive Economic Zone (EEZ) during an investigation of fishery resources by the National Fisheries Research and Development Institute (NFRDI) from 2002 to 2010, alongside some supplemental material, six species of the genus $Plesionika$ are identified: $P.$ $izumiae$ Omori, 1971, $P.$ $ortmanni$ Doflein, 1902, $P.$ $grandis$ Doflein, 1902, $P.$ $lophotes$ Chace, 1985, $P.$ $narval$ (Fabricius, 1787), and $P.$ $orientalis$ Chace, 1985. Of these, the last four species are new to Korean marine fauna. The distributional range of $P.$ $narval$ extends to the East China Sea off Jeju Island. Excluding $P.$ $izumiae$ and $P.$ $ortmanni$, the other four species are relatively rare in the seas around Korea. They are described and illustrated with color photographs. A key to the Korean species of $Plesionika$ is also presented.

• Journal of applied mathematics & informatics
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• 제30권5_6호
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• pp.793-807
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• 2012

If G is any connected graph of order p; then the thorn graph $G_p^*$ with code ($n_1$, $n_2$, ${\cdots}$, $n_p$) is obtained by adding $n_i$ pendent vertices to each $i^{th}$ vertex of G. By treating the pendent edge of a thorn graph as $P_2$, $K_2$, $K_{1,1}$, $K_1{\circ}K_1$ or $P_1{\circ}K_1$, we generalize a thorn graph by replacing $P_2$ by $P_m$, $K_2$ by $K_m$, $K_{1,1}$ by $K_{m,n}$, $K_1{\circ}K_1$ by $K_m{\circ}K_1$ and $P_1{\circ}K_1$ by $P_m{\circ}K_1$ and their respective generalized thorn graphs are denoted by $G_P$, $G_K$, $G_B$, $G_{KK}$ and $G_{PK}$ respectively. Many chemical compounds can be treated as $G_P$, $G_K$, $G_B$, $G_{KK}$ and $G_{PK}$ of some graphs in graph theory. In this paper, we obtain the bounds of the wiener index for these generalization of thorn graphs.

• 대한수학회보
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• 제55권5호
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• pp.1441-1462
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• 2018

In this paper, we investigate the fractional p&q-Kirchhoff type system $$\{M_1([u]^p_{s,p})(-{\Delta})^s_pu+V_1(x){\mid}u{\mid}^{p-2}u\\{\hfill{10}}={\ell}k^{-1}F_u(x,\;u,\;v)+{\lambda}{\alpha}(x){\mid}u{\mid}^{m-2}u,\;x{\in}{\Omega}\\M_2([u]^q_{s,q})(-{\Delta})^s_qv+V_2(x){\mid}v{\mid}^{q-2}v\\{\hfill{10}}={\ell}k^{-1}F_v(x,u,v)+{\mu}{\alpha}(x){\mid}v{\mid}^{m-2}v,\;x{\in}{\Omega},\\u=v=0,\;x{\in}{\partial}{\Omega},$$ where ${\Omega}{\subset}{\mathbb{R}}^N$ is an unbounded domain with smooth boundary ${\partial}{\Omega}$, and $0<s<1<p{\leq}q$ and sq < N, ${\lambda},{\mu}>0$, $1<m{\leq}k<p^*_s$, ${\ell}{\in}R$, while $[u]^t_{s,t}$ denotes the Gagliardo semi-norm given in (1.2) below. $V_1(x)$, $V_2(x)$, $a(x):{\mathbb{R}}^N{\rightarrow}(0,\;{\infty})$ are three positive weights, $M_1$, $M_2$ are continuous and positive functions in ${\mathbb{R}}^+$. Using variational methods, we prove existence of infinitely many high-energy solutions for the above system.

• Kyungpook Mathematical Journal
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• 제47권3호
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• pp.335-340
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• 2007

Let M be a hyperbolic 3-manifold such that ${\partial}M$ has at least two boundary tori ${\partial}_oM$ and ${\partial}_1M$. Suppose that M contains an essential orientable surface P of genus $g$ with one outer boundary component ${\partial}_oP$, lying in ${\partial}_oM$ and having slope ${\lambda}$ in ${\partial}_oM$, and $p$ inner boundary components ${\partial}_iP$, $i=1$, ${\cdots}$, $p$, each having slope ${\alpha}$ in ${\partial}_1M$. Let ${\beta}$ be a slope in ${\partial}_1M$ and suppose that $M({\beta})$ is toroidal. Let $\hat{T}$ be a minimal essential torus in $M({\beta})$, which means that $\hat{T}$ is pierced a minimal number of times by the core of the ${\beta}$-Dehn filling, among all essential tori in $M({\beta})$. Let $T=\hat{T}{\cap}M$ and denote by $t$ the number of components of ${\partial}T$. In this paper we prove: (i) if $t{\geq}3$, then ${\Delta}({\alpha},{\beta}){\leq}6+\frac{10g-5}{p}$, (ii) If $t=2$, then ${\Delta}({\alpha},{\beta}){\leq}13+\frac{24g-12}{p}$, (iii) If $t=1$, then ${\Delta}({\alpha},{\beta}){\leq}1$.

• 한국수산과학회지
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• 제27권3호
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• pp.265-271
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• 1994

천연산 및 양식산 미꾸라지와 미꾸리 표피의 carotenoid 조성을 thin-layer chromatography, column chromatography로 분리하고, $I_2$에 의한 이성화 반응 및 용매에 따른 가시부 흡수 spectrum을 비교, 검토한 결과는 다음과 같다. 1) 미꾸라지 표피의 총 carotenold함량은 천연산 $4.76mg\%$인데 비하여 양식산 $3.43mg\%$로서 천연산이 양식산보다 함량이 높았다. Carotenoid 조성은 천연산에서 lutein $30.5\%$, ${\beta}$-cryptoxanthin $24.6\%$, ${\beta}$-carotene $20.6\%$, cynthiaxanthin $11.7\%$로서 주성분을 이루고, 그 외 zeaxanthin $4.7\%$, tunaxanthin $4.5\%$, a-cryptoxanthin $1.0\%$의 순으로 함유되었으며, 양식산에는 lutein $35.4\%$, ${\beta}$-cryptoxanthin $17.9\%$, cynthiaxanthin $16.0\%$, ${\beta}$-carotene $12.7\%$로서 주성분을 이루고, 그 외 zeaxanthin $8.2\%$, tunaxanthin $5.0\%$, a-cryptoxanthin $0.9\%$순으로 함유되어, 천연산은 양식산에 비하여 ${\beta}$-carotene 및 ${\beta}$-cryptoxanthin의 함유비가 높은 반면, lutein의 함유비가 낮은 경향을 보여 서로 차이를 나타내었다. 2) 미꾸리 표피의 총 carotenoid함량은 천연산 $4.00mg\%$인데 비하여 양식산 $2.99mg\%$로서 미꾸라지에서와 같이 천연산이 양식산보다 함량이 높았다. Carotenoid조성은 천연산에서 lutein $32.9\%$, ${\beta}$-cryptoxanthin $18.8\%$, cynthiaxanthin $17.0\%$, ${\beta}$-carotene $15.1\%$로서 주성분을 이루고, 그 외 zeaxanthin $6.5\%$, tunaxanthin $6.0\%$, a-cryptoxanthin $1.5\%$의 순으로 함유되었으며, 양식산에는 lutein $51.8\%$, cynthiaxanthin $19.9\%$, ${\beta}$-cryptoxanthin $10.8\%$로서 주성분을 이루고, 그 외 ${\beta}$-carotene $5.0\%$, zeaxanthin $4.8\%$, tunaxanthin $4.5\%$, a-cryptoxanthin $0.2\%$의 순으로 함유되어, 미꾸라지에서와 같이 천연산은 양식산에 비하여 ${\beta}$-carotene 및 ${\beta}$-cryptoxanthin의 함유비가 높은 반면, lutein의 함유비가 낮은 경향을 보여 서로 상이 하였으며, 미꾸라지와 미꾸리 표피의 carotenoid 함유비는 다소 차이는 있었지만, 조성에 있어서는 서로 유사하였다.

• 한국환경농학회지
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• 제26권1호
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• pp.42-48
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• 2007

본 조사는 충북지역의 양액재배 농가에서 양액재배를 위한 지하수 수질과 양액 재배 후 버려지는 폐양액의 수질에 대한 기초 자료를 얻고자 수행되었다. 양액재배를 위한 지하수의 수질 조사는 19개 지점의 양액재배농가에서 수집하여 분석하였고, 폐양액은 그중 15개 지점을 선택하여 분석하였다. 양액재배에 이용되는 지하수의 수질 분석결과 pH의 수준은 $6.2\sim7.7$이었고, 평균은 6.8이었다. EC의 분포범위는$0.10\sim0.45$ dS $m^{-1}$ 이었고, 평균은 0.23 dS $m^{-1}$ 이었다. $NO_3-N$ 농도의 분포범위는 $0.12\sim13.77$ mg $L^{-1}$, $SO_4^{2-}$의 분포범위는 $1.84\sim63.01$ mg $L^{-1}$, 그리고 $Cl^-$의 분포범위는 $10.46\sim72.09$ mg $L^{-1}$이었다. 그들의 평균값은 각각 4.00 mg $L^{-1}$, 12.70 mg $L^{-1}$ 및 27.57 mg $L^{-1}$이었다. $Ca^{2+}$, $Mg^{2+}$ 및 $Na^+$의 분포 범위는 각각 $3.24\sim36.99$ mg $L^{-1}$, $1.44\sim14.93$ mg $L^{-1}$ 및 $6.12\sim25.25$ mg $L^{-1}$이었고, 평균 농도 값은 $Ca^{2+}$ 13.06, $Mg^{2+}$ 6.02 및 $Na^+$ 12.08 mg $L^{-1}$이었다. 양액재배 후 버려지는 폐양액에서 pH 수준은 $4.3\sim8.8$ 이었고, 평균은 6.7이었다. EC의 분포범위는 $0.44\sim2.37$ dS $m^{-1}$이었고, 평균은 1.15 dS $m^{-1}$이었다. $NO_3-N$, $PO_4-P$, $K^+$, $Ca^{2+}$, $Mg^{2+}$ 및 $Na^+$ 의 분포범위는 각각 $10\sim212$, $0.56\sim26.1$, $10\sim295$, $16\sim215$, $9\sim54$ 및 $10\sim53$ mg $L^{-1}$이었다. 평균 농도 값은 $NO_3-N$ 100, $PO_4-P$ 12.15, $K^+$ 99, $Ca^{2+}$ 78, $Mg^{2+}$ 26 및 $Na^+$ 26 mg $L^{-1}$이었다. 양액 재배 후 버려지는 폐양액 중의 무기성분 함량은 양액재배에 이용되는 원수에 비해 상당히 높아졌다.