• Journal of Surface Science and Engineering
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• v.56 no.5
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• pp.299-308
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• 2023

In this study, phosphorus (P)-doped nickel cobaltite (P-NiCo₂O₄) and nickel-cobalt layered double hydroxide (P-NiCo-LDH) were synthesized on nickel (Ni) foam as a conductive support using hydrothermal synthesis. The thermal properties, crystal structure, microscopic surface morphology, chemical distribution, electronic state of the constituent elements on the sample surface, and electrical properties of the synthesized P-NiCo₂O₄ and P-NiCo-LDH samples were analyzed using thermogravimetric analysis-differential scanning calorimetry (TGA-DSC), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The P-NiCo₂O₄ electrode exhibited a specific capacitance of 1,129 Fg^-1 at a current density of 1 Ag^-1, while the P-NiCo-LDH electrode displayed a specific capacitance of 1,012 Fg^-1 at a current density of 1 Ag-1. When assessing capacity changes for 3,000 cycles, the P-NiCo₂O₄ electrode exhibited a capacity retention rate of 54%, whereas the P-NiCo-LDH electrode showed a capacity retention rate of 57%.

• Bulletin of the Korean Mathematical Society
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• v.43 no.4
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• pp.693-701
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• 2006

Using Minimax principle and Linking theorem in critical point theory, we prove the existence of two nontrivial solutions for the following second order superlinear difference systems $$(P)\{{\Delta}^2x(k-1)+g(k,y(k))=0,\;k{\in}[1,\;T],\;{\Delta}^2y(k-1)+f(k,\;x(k)=0,\;k{\in}[1,\;T],\;x(0)=y(0)=0,\;x(T+1)=y(T+1)=0$$ where T is a positive integer, [1, T] is the discrete interval {1, 2,..., T}, ${\Delat}x(k)=x(k+1)-x(k)$ is the forward difference operator and ${\Delta}^2x(k)={\Delta}({\Delta}x(k))$.

• Journal of the Korean Mathematical Society
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• v.51 no.4
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• pp.853-866
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• 2014

Constacyclic codes of length $p^s$ over $R=\mathbb{F}_{p^m}+u\mathbb{F}_{p^m}+u^2\mathbb{F}_{p^m}$ are precisely the ideals of the ring $\frac{R[x]}{<x^{p^s}-1>}$. In this paper, we investigate constacyclic codes of length $p^s$ over R. The units of the ring R are of the forms ${\gamma}$, ${\alpha}+u{\beta}$, ${\alpha}+u{\beta}+u^2{\gamma}$ and ${\alpha}+u^2{\gamma}$, where ${\alpha}$, ${\beta}$ and ${\gamma}$ are nonzero elements of $\mathbb{F}_{p^m}$. We obtain the structures and Hamming distances of all (${\alpha}+u{\beta}$)-constacyclic codes and (${\alpha}+u{\beta}+u^2{\gamma}$)-constacyclic codes of length $p^s$ over R. Furthermore, we classify all cyclic codes of length $p^s$ over R, and by using the ring isomorphism we characterize ${\gamma}$-constacyclic codes of length $p^s$ over R.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.225-230
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• 2022

A new two-fold interpenetrating two-dimensional (2D) Tb(III) metal-organic framework (MOF), [Tb(p-XBP4)_2.5(H₂O)₂]·W(CN)₈ (1), was prepared using a p-XBP4 (N,N'-p-phenylenedimethylenbis(pyridin-4-one)), Cs₃[W(CN)₈], and Tb(NO₃)₃·6H₂O. The single crystal X-ray diffraction indicated that Tb-MOF exhibits a unique two-fold interpenetrating 2-D framework. It was also characterized through Fourier transform infrared spectroscopy (FTIR), and single and powder X-ray diffraction. To probe the molecular magnetic behavior, the magnetic properties of Tb-MOF were investigated by direct-current (DC) and alternating-current (AC) magnetic susceptibilities measurements and discussed.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.2
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• pp.31-40
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• 2014

Purpose : To evaluate the effect of cervical strengthening exercise on balance ability in healthy adults. Method : The subjects consisted of forty healthy people. The subjects were divided into two group. The control group(n=14) received no exercise and/or stimulation. The cervical strengthening exercise group(n=14) performed therapeutic intervention using cervical exercise for strengthening of cervical spine muscle. The exercise group were accomplished during 6 weeks(2~3set, 5times/week). All tests were completed before and after experiment. The static balance ability was measured by normal standing when subjects open and close their eyes on GOOD BALANCE SYSTEM, respectively. For each case, the experimental data were obtained in 3 items: mean X speed, mean Y speed and velocity moment. Result : The results of this study were as follows; 1. In the exercise group, the statistically significant difference were shown on X speed and Y speed in the case of normal standing when subjects open and close their eyes and X speed, Y speed and velocity moment in the case of normal standing when subjects close their eyes(p<0.05). 2. In control group, the statistically significant difference were not shown on all posture(p>0.05). 3. There were a statistically significant difference in the X speed and Y speed in the case of normal standing when subjects open their eyes between control group and the exercise group(p<0.05). There were a statistically significant difference in the X speed, Y speed and velocity moment in the case of normal standing when subjects close their eyes between control group and exercise group(p<0.05). Conclusion : The above results revealed that therapeutic intervention for muscle strengthening of cervical there were positive changes to balance ability.

• The Pure and Applied Mathematics
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• v.2 no.2
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• pp.157-162
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• 1995

Let I be the interval, $S^1$ the circle and let X be a compact metric space. And let $C^{circ}(X,\;X)$ denote the set of continuous maps from X into itself. For any f$f\in\;C\circ(X,\;X),\;let\;P(f),\;R(f),\;\Gamma(f),\;\Lambda(f)\;and\;\Omega(f)$ denote the collection of the periodic points, recurrent points, ${\gamma}-limit{\;}points,{\;}{\omega}-limit$ points and nonwandering points, respectively.(omitted)

• Journal of the Korean Statistical Society
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• v.3 no.1
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• pp.59-63
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• 1974

표현형 변수 Y가 유전변수 X와 환경변수 E로 표시되고 X와 E가 상호독립이며 각각 다음과 같은 정규분포를 한다고 하자. $$X\simN(\mu,\sigma^2), E\simN)0,\omega^2)$$ 대체로 $Y \geq y$이거나 $Y \leq y$인 형태일 때 유전 및 육동적 선발은 Y=X+E의 형태로 나타난다. 롭슨[3]은 선발을 반복하였을 때 유전변수 X의 평균기대치와 유전변수 X의 조건부분포의 영향을 연구하였고 이와같은 일변량분포의 경우 선발의 효과는 전분산에 대한 유전분산의 비에 달려있다 하였다. 이러한 선발모형을 p-차원 공간에 적용하면 유전편차의 비율을 구할 수 있다.

• Bulletin of the Korean Chemical Society
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• v.4 no.2
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• pp.92-95
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• 1983

The addition products of glutathione to ${\beta}$ -nitrostyrene derivatives were synthesized. ${\beta}$ -Nitrostyrene (1a), p-methyl-${\beta}$-nitrostyrene (1b), 3,4,5-trimethoxy-${\beta}$-nitrostyrene (1c), o-, m- and p-chloro-${\beta}$-nitrostyrene (1e, 1f, 1g) and o-, m- and p-methoxy-${\beta}$-nitrostyrene (1h, 1i, 1j) undergo addition reactions with glutathione to form S-(2-nitro-1-phenylethyl)-L-glutathione (5a), S-[2-nitro-1-(p-methyl)phenylethyl]-L-glutatione (5b), S-[2-nitro-1-(3', 4', 5'-trimethoxy)phenylethyl]-L-glutathione (5c), S-[2-nitro-1-(o-chloro)phenylethyl]-L-glutathione (5e), S-[2-nitro-1-(m-choro)phenylethyl]-L-glutathione (5f), S-[2-nitro-1-(p-chloro)phenylethyl]-L-glutathione (5g), S-[2-nitro-x-(o-methoxy)-phenylethyl]-L-glutathion e(5h), S-[2-nitro-x-(m-methoxy)phenylethyl]-L-glutathion e (5i), and S-[2-nitro-1-(p-methoxy)phenylethy])-L-glutathione (5j), respectively. The structure of adducts were identified by UV and IR-spectra, molecular weight measurement, and elemental analysis.

• Review of KIISC
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• v.17 no.1
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• pp.63-78
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• 2007

국제표준화기구 ITU-T SG17 WP2에서는 정보통신 보안에 관한 표준을 주도하는 연구그룹으로, 산하 7개의 연구과제(Question)를 구성하여 정보보호 표준화 작업을 진행하고 있다. 이 연구과제들 중 Q.9/17에서는 안전한 통신 서비스라는 이름으로 모바일 보안, 홈네트워크 보안, 웹 서비스 보안, 그리고 안전한 응용 프로토콜 등에 대한 표준을 개발 중에 있다. 현재, Q.9/17에서 제정된 표준은 한국과 일본이 공동으로 제안하여 2004년 3월에 제정된 모바일보안 2건(X.1121, X.1122)과 OASIS의 제안으로 2006년 6월에 제정된 웹서비스 보안 2건(X.1141, X.1142)이 표준으로 제정된 바 있다. 그리고 Q.9/17에서 작업중에 있는 표준초안은 모바일 보안 3건, 홈네트워크 보안 3건, 웹서비스 보안 1건, 안전한 응용 프로토콜 2건, P2P보안 2건 및 RFID보안 1건에 대해서 개발중에 있다. 특히, 이번 12월 제네바 회의에서는 한국 주도로 개발된 홈네트워크를 위한 보안기술 프레임워크(X.homesec-1) 표준초안이 SG17 총회에서 승인되어 국가별 의견수렴(consent)을 추진키로 합의되었다. 본 논문에서는 Q.9/17에서 수행되고 있는 표준초안들에 대해 간단히 소개하고, 2006년 9월 캐나다 오타와 회의와 2006년 12월 스위스 제네바 회의에서의 주요쟁점사항 및 토론 결과, 그리고 향후 추진방향을 제시하고자 한다.

• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.55-61
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• 2011

This study investigate the use of ultraviolet(UV) light with hydrogen peroxide($H_2O_2$) for Methyl Tert Butyl Ether(MTBE) degradation in photolysis reactor. The process in general demands the generation of OH radicals in solution at the presence of UV light. These radicals can then attack the MTBE molecule and it is finally destroyed or converted into a simple harmless compound. The MTBE removal by photolysis were mathematically described as the independent variables such as irradiation intensity, initial concentration of MTBE and $H_2O_2$/MTBE ratio, and these were modeled by the use of response surface methodology(RSM). These experiments were carried out as a Box-Behnken Design(BBD) consisting of 15 experiments. Regression analysis term of Analysis of Variance(ANOVA) shows significantly p-value(p<0.05) and high coefficients for determination values($R^2$=94.60%) that allow satisfactory prediction of second-order regression model. And Canonical analysis yields the stationery point for response, with the estimate ridge of maximum responses and optimal conditions for Y(MTBE removal efficiency, %) are $x_1$=25.75 W of irradiation intensity, $x_2$=7.69 mg/L of MTBE concentration and $x_3$=11.04 of $H_2O_2$/MTBE molecular ratio, respectively. This study clearly shows that RSM is available tool for optimizing the operating conditions to maximize MTBE removal.