• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.3
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• pp.193-200
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• 1996

In this paper, Strip Halo Antenna used for the proximity sensor in 800 MHz band was fabricated by using a dielectric board with the relative dielectric constant of 6.15. Dimensions of the strip halo antenna were optimized by the theoretical simulation and many experiments. The impedance of the strip halo antenna mounted on the proximity sensor with the finite circular groud plane was measured as 16.5 + j1.1[$\Omega$]. The matching characteristic of the strip halo antenna was greatly improved by attaching the matching section designed through experiments to the rear side of dielectric board. The impedance of the strip halo antenna with the matching section was measured as 43.79-j0.04[$\Omega$], and the 3 dB beam width of its radiation pattern was measured about $90^{\circ}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.178.2-178.2
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• 2015

In and Ga doped ZnO (IGZO) films were deposited on 5 nm thick Cu film buffered Polycarbonate (PC) substrates with RF magnetron sputtering and then the effect of Cu buffer layer on the optical and electrical properties of the films was investigated. While IGZO single layer films show the electrical resistivity of $1.2{\times}10-1{\Omega}cm$, IGZO/Cu bi-layered films show a lower resistivity of $1.6{\times}10-3{\Omega}cm$. Although the optical transmittance of the films in a visible wave length range is deteriorated by Cu buffer layer, IGZO films with 5 nm thick Cu buffer layer show the higher figure of merit of $2.6{\times}10-4{\Omega}-1$ than that of the IGZO single layer films due to the enhanced opto-electrical performance of the IGZO/Cu bi-layered films.

• Electrical & Electronic Materials
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• v.4 no.1
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• pp.31-37
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• 1991

습도센서용 기판으로 사용하기 위한 MgFe$_{2}$O$_{4}$ 세라믹스의 성능개선을 위하여 Li$_{2}$CO$_{3}$와 V$_{2}$O$_{5}$를 첨가한 MgFe$_{2}$O$_{4}$-LiMgVO$_{4}$ 세라믹스를 만들고, 기공율, 기공분포, 센서특성, 응답속도 등을 조사하여 다음의 결과를 얻었다. 기공율은 MgFe$_{2}$O$_{4}$ 세라믹스가 29[%]에서 34[%]인데 비하여 본 연구결과는 34.5[%]에서 39[%]로 증가하였으며 센서특성은 $10^{7}$ [.OMEGA.] 단위의 변화에서 $10^{7}$ [.OMEGA.]에서 $10^{6}$[.OMEGA.] 단위로 변화함을 알수 있었고 응답속도는 10초정도 빨라졌음을 알수 있었다. 또한 기공분포를 이용하여 모형 센서를 제안하여 시뮬레이션을 하고 실제 특성과 이론적인 특성을 비교하였다.

• Journal of the Korean Data and Information Science Society
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• v.13 no.2
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• pp.307-315
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• 2002

Suppose one is given a vector X of a finite set of quantities $X_i$ which are independent Poisson signals. A null hypothesis $H_0$ about E(X) is to be tested against an alternative hypothesis $H_1$. A quantity $$\sum\limits_{i}\omega_ix_i$$ is to be computed and used for the test. The optimal values of $\omega_i$ are calculated for three cases : (1) signal to noise ratio is used in the test, (2) normal approximations with unequal variances to the Poisson distributions are used in the test, and (3) the Poisson distribution it self is used. A comparison is made of the optimal values of $\omega_i$ in the three cases as parameter goes to infinity.

• Bulletin of the Korean Mathematical Society
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• v.39 no.2
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• pp.289-297
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• 2002

It was shown by L. Polterovich ([3]) that if L is a totally real submanifold of a symplectic manifold $(M,\omega)$ and L is parallelizable then L is normal. So we try to find an answer to the question of whether there is a compatible almost complex structure J on the symplectic vector bundle $TM$\mid$_{L}$ such that $TL{\cap}JTL=0$ assuming L is normal and parallelizable. Although we could not reach an answer, we observed that the claim holds at the vector space level. And related to the question, we showed that for a symplectic vector bundle $(M,\omega)$ of rank 2n and $E=E_1{\bigoplus}E_2$, where $E=E_1,E_2$are Lagrangian subbundles of E, there is an almost complex structure J on E compatible with ${\omega}$ and $JE_1=E_2$. And finally we provide a necessary and sufficient condition for a given embedding into a symplectic manifold to be normal.

• Bulletin of the Korean Mathematical Society
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• v.49 no.4
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• pp.787-797
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• 2012

In this paper the authors study the $L^p$ boundedness for parabolic Littlewood-Paley operator $${\mu}{\Phi},{\Omega}(f)(x)=\({\int}_{0}^{\infty}{\mid}F_{\Phi,t}(x){\mid}^2\frac{dt}{t^3}\)^{1/2}$$, where $$F_{\Phi,t}(x)={\int}_{p(y){\leq}t}\frac{\Omega(y)}{\rho(y)^{{\alpha}-1}}f(x-{\Phi}(y))dy$$ and ${\Omega}$ satisfies a condition introduced by Grafakos and Stefanov in [6]. The result in the paper extends some known results.

• Journal of Pharmaceutical Investigation
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• v.12 no.3
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• pp.64-73
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• 1982

Molecular structures of ${\omega}-Amino$ acids, ${\omega}-Aminosulfonic$ acids and their ${\beta}-hydroxy$ substituted compounds were determined by X-ray diffraction method, and the similarities and differences between their molecular structures or between related compounds were discussed.

• Communications of the Korean Mathematical Society
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• v.13 no.2
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• pp.233-242
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• 1998

Let $k = Q(\sqrt{m})$ be a real quadratic field. In this paper, the following theorems on p-divisibility of the class number h of k are studied for each prime pp. Theorem 1. If the discriminant of k has at least three distinct prime divisors, then 2 divides h. Theorem 2. If an odd prime p divides h, then p divides $B_{a,\chi\omega^{-1}}$, where $\chi$ is the nontrivial character of k, and $\omega$ is the Teichmuller character for pp. Theorem 3. Let $h_n$ be the class number of $k_n$, the nth layer of the $Z_p$-extension $k_\infty$ of k. If p does not divide $B_{a,\chi\omega^{-1}}$, then $p \notmid h_n$ for all $n \geq 0$.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.15-23
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• 1999

K-$\omega$ model is used for simulation of flowfield around the cylinderical afterbody. In addition to two-equation turbulence model, modification terms for the compressibility effects are applied to the simulation. Although the estimations of the skin friction and the surface pressure distribution at hypersonic ramp flowfield were satisfactory, the result of the simulation with the modifications for this flowfield is worse than that of the original K-$\omega$ model. The compressiblility modification terms do negative effects on the estimation. The basic research on the turbulence model for the compressible flowfield has to be further conducted.

• Journal of Photoscience
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• v.8 no.3_4
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• pp.99-104
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• 2001

Studies have been conducted to explore single electron transfer (SET) promoted photocyclization reactions of ($\omega$-phthalimidoalkylthio)acetic acids (alkyl=ethyl, n-propyl, n-butyl, n -hexyl and n-nonyl). Photocyclizations occur in methanol in modest yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the carboxylic group. The initially formed cyclized products undergo efficient water eliminations to produce enthiol ethers in secondary ground state reactions.