• Bulletin of the Korean Mathematical Society
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• v.53 no.4
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• pp.1157-1169
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• 2016

We find the distributional solutions of the Wilson's functional equations $$u{\circ}T+u{\circ}T^{\sigma}-2u{\otimes}v=0,\\u{\circ}T+u{\circ}T^{\sigma}-2v{\otimes}u=0,$$ where $u,v{\in}{\mathcal{D}}^{\prime}({\mathbb{R}}^n)$, the space of Schwartz distributions, T(x, y) = x + y, $T^{\sigma}(x,y)=x+{\sigma}y$, $x,y{\in}{\mathbb{R}}^n$, ${\sigma}$ an involution, and ${\circ}$, ${\otimes}$ are pullback and tensor product of distributions, respectively. As a consequence, we solve the $Erd{\ddot{o}}s$' problem for the Wilson's functional equations in the class of locally integrable functions. We also consider the Ulam-Hyers stability of the classical Wilson's functional equations $$f(x+y)+f(x+{\sigma}y)=2f(x)g(y),\\f(x+y)+f(x+{\sigma}y)=2g(x)f(y)$$ in the class of Lebesgue measurable functions.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.453-458
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• 2019

Synthesis of ZnCo₂O₃ oxide is performed by sol-gel method via nitrate-citrate route. Powder X-ray diffraction (XRD) study shows monoclinic unit cell having lattice parameters: a = 5.721(1) Å, b = 8.073(2) Å, c = 5.670(1) Å, β = 93.221(8)°, space group P_2/m and Z = 4. Average crystallite sizes determined by Scherrer equation are the range ~14-32 nm, whereas SEM micrographs show nano-micro meter size particles formed in ZnCo₂O₃. Endothermic peak at ~798 K in the Differential scanning calorimetric (DSC) trace without weight loss could be due to structural transformation and the endothermic peak ~1143 K with weight loss is due to reversible loss of O₂ in air atmosphere. Energy Dispersive X-ray (EDX) analysis profile shows the presence of elements Zn, Co and O which indicates the purity of the sample. Magnetic measurements in the range of +12 kOe to -12 kOe at 10 K, 77 K, 120 K and at 300 K by PPMS-II Physical Property Measurement System (PPMS) shows hysteresis loops having very low values of the coercivity and retentivity which indicates the weakly ferromagnetic nature of the oxide. Observed X-band EPR isotropic lineshapes at 300 K and 77 K show positive g-shift at g_iso ~2.230 and g_iso ~2.217, respectively which is in agreement with the presence of paramagnetic site Co²⁺(3d⁷) in the oxide. DC conductivity value of 2.875 ×10^-8 S/cm indicates very weakly semiconducting nature of ZnCo₂O₃ at 300 K. DRS absorption bands ~357 nm, ~572 nm, ~619 nm and ~654 nm are due to the d-d transitions ⁴T_1g(⁴F)→²E_g(²G), ⁴T_1g(⁴F)→⁴T_1g(⁴P), ⁴T_1g(⁴F)→⁴A_2g(⁴F), ⁴T_1g(⁴F)→⁴T_2g(⁴F), respectively in octahedral ligand field around Co²⁺ ions. Direct band gap energy, E_g~ 1.5 eV in the oxide is obtained by extrapolating the linear part of the Tauc plot to the energy axis indicates fairly strong semiconducting nature of ZnCo₂O₃.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.57-62
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• 1977

Der Zuwachs des Durchmessers des Einzelbaumes kann durch die Differenzialgleichung dx/dt=k(M-x)+f(t) beschrieben werder, wobei f(t) die von den zuf$\ddot{a}$lligen $\ddot{A}$nderungen der Umwelt bedingte Fluktuation des Wachstums bedeutet. Nach dieser Gleichung kann das Wachstum des Durchmessers des Einzelbaumes in zwei Teile zerlegt werden: der erste systematische Teil k(M-x) repr$\ddot{a}$sentiert den Trend des Wachstums und der zweite Teil die Fluktuation f(t), die f$\ddot{u}$r die Wald bewirtschaftung von Praktischer Bedeutung ist. Die Studie zeigt die mathematische Ableitung zur Bestimmung von f(t).

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.4
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• pp.395-411
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• 2001

Die $W\"{o}rterb\"{u}cher$ spielen beim Erwerb einer Sprache eine wesentliche Rolle. Es gibt inzwischen mehrere Deutsch-Koreanische $W\"{o}rterb\"{u}cher$. Die Lage $f\"{u}r$ die Koreanisch-Deutschen $W\"{o}rterb\"{u}cher$ ist aber verbesserungs- $bed\"{u}rftig$. Stellvertretend $f\"{u}r$ das Koreanisch/Deutsche $W\"{o}rterbuch$ steht das 1981 von der Koreanischen Gesellschaft $f\"{u}r$ Germanistik nach $zehnj\"{a}hriger$ Arbeit fertiggestellte Essence Koreanisch-Deutsche $W\"{o}rterb\"{u}ch$ (Minjung seorim 1982). Dieses $W\"{o}rterb\"{u}ch$ weist aber einige Nachteilen auf. Es fehlen jegliche Angaben zum Korpus. Man $st\"{o}{\ss}t$ beispielsweise oft auf selten gebrauchte $W\"{o}rter$, die Grundbedeutungen sind nicht erkennbar, die Erklarungen sind ungenau, manchmal sogar $irref\"{u}hrend\;und\;schlie{\ss}lich$ mitunter stilistisch falsch. Diese negativen Punkte wirken sich $ung\"{u}nstig$ auf den gesamten Lemprozess bis hin zur Lemmotivation aus. Aus diesen Gegebenheiten $erw\"{a}chst$ die Notwendigkeit der Erstellung eines neuen $W\"{o}rterb\"{u}ch$s, das auf die Situation von Sprachlemem abgestimmt ist, die zur Benutzung einsprachiger $W\"{o}rterbticher$ noch nicht imstande sind. Zweck des $W\"{o}rterb\"{u}chs$ ist der Einsatz im Fremdsprachenunterricht, woraus sich ein zweisprachiges $W\"{o}rterb\"{u}ch$ ergibt. Als Benutzerkreis werden insbesondere $Sprachlemanf\"{a}nger$ des Koreanischen und Deutschen ins Auge gefasst. Ihnen soll ein Nachschlagewerk an die Hand gegeben werden, das den koreanischen und deutschen Wortschatz anhand einer Systematik und eines alphabetischen Indexes der jeweiligen Sprache $erschlie{\ss}t$. Ais Zahl der Lemmata wird $f\"{u}r$ jede Sprache ca. 10,000 festgelegt. Ein Grundwortschatz, der die 3000 $h\"{a}ufigsten\;W\"{o}rter$ umfasst wird extra markiert. $Dar\"{u}ber$ hinaus bietet das $W\"{o}rterb\"{u}ch$ den darauf aufbauende Wortschatz von weiteren 7000 $W\"{o}rtern$. Die Teamarbeit der beiden Gruppen von Muttersprachlern steht in allen Arbeitsschritten im Vordergrund. Der damit verbundene Zweck ist die Erzielung der maximalen Genauigkeit der $Lemmaerkl\"{a}rungen$. Da dieses $W\"{o}rterb\"{u}ch$ ein $W\"{o}rterb\"{u}ch$ nach Sachgruppen ist, die Erstellung einer Systematik von $gro{\ss}er$ Bedeutung. $F\"{u}r$ das vorliegende Projekt gait daher eine Systematik zu finden, die nicht nur leicht nachvollziehbar, also praktikabel ist, sondern insbesondere von Benutzern aus zwei Kulturkreisen akzeptiert werden kann. Als $grunds\"{a}tzliche$, allerdings nicht in allen Bereichen $gleicherma{\ss}en$ anwendbare Ordnungsprinzipien gelten: Vom Oberbegriff zum Unterbegriff, vom allgemein zum speziell, vom Einfach zum Komplexen, von $au{\ss}en$ nach innen, Darin spiegelt sich das Prinzip der 'notwendigen Bedingung' wider.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1073-1079
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• 1998

The potential energy surface (PES) of the non-identical SN2 reactions, F- + CH3Cl → FCH3 + Cl and (H2O)F + CH3Cl → FCH3 + Cl-(H2O), were investigated with ab initio MO calculations. The ab initio minimum energy reaction path (MERP) of the F- + CH3Cl → FCH3 + Cl- was obtained and it was expressed with an intermediate variable t. The ab initio PES was obtained near around t. Analytical potential energy function (PEF) was determined as a function of the t in order to reproduce the ab initio PES. Based on Morse-type potential energy function, a Varying Repulsive Cores Model (VRCM) was proposed for the description of the bond forming and the bond breaking which occur simultaneously during the SN2 reaction. The MERP calculated with the PEF is well agreed with the ab initio MERP and PEF could reproduce the ab initio PES well. The potential parameters for the interactions between the gas phase molecules in the reactions and water were also obtained. ST2 type model was used for the water.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.98-102
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• 1995

The crystal structure of -Ethyl-1,4-dihydro-7-methyl-1,8-naphthyridin-4-one-3-carboxylic acid [Nalicixic Acid] has been determined from single crystal X-ray diffraction study; C12H12N2O3, monoclinic, P21/c, a=8.910(2)Å, b=13.145(3)Å, c=9.370(3)Å, β =100.06(2)°, V=1080.6Å, T=293K, Z=4, CuKα(λ=1.5418Å). The molecular structure was solved by direct method and refined by full-matrix least squares to a final R=0.055 for 1555 unique observed [F0>4σ(F0)] reflections and 166 parameters. The conformation of the molecule is stabilized by an intramolecular O(17)-H(17)…O(14) hydrogen bond [2.525(2)Å, 144.3(10)°].

• Korean Journal of Crystallography
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• v.15 no.2
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• pp.93-98
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• 2004

The structure of C_{28}H_{41}N_4O_4Br\;{\cdot}\;2H_2O$ has been determined by X-ray deffraction methods. The crystal system is triclinic, space group Pl, unit cell constants, a=9.000(1) $\AA$, b=9.312(3) $\AA$, c=9.344(2) $\AA$, $\alpha=89.37(20)^{\circ},\;\beta=68.81(3)^{\circ},\;\gamma=84.70(4)^{\circ},\;V=726.7(8){\AA},\;T=298K,\;Z=1,\;D_c=1.402Mgm^{-3}$. The intensity data were collected on an Enraf-Nonius CAD4 Diffractometer with graphite monochromated $MoK\alpha$ radiation $(\lambda=0.71073\;{\AA}$. The molecular structure was solved by direct methods and refined by full-matrix least squares to a final $R=5.95\%$ for 2521 unique observed $F_0>4\sigma(F_0)$reflections and 370 parameters.

• Journal of Integrative Natural Science
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• v.12 no.4
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• pp.101-104
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• 2019

A hydrated strontium iron fluoride, Sr₂Fe₂F₁₀(H₂O) has been synthesized and characterized. The material was synthesized through mild hydrothermal reaction using an aqueous CF₃COOH solution. The material exhibits a one-dimensional structure consisting of chains of corner-shared Fe³⁺F₆ octahedra, isolated Fe³⁺F₅(H₂O) octahedra, chains of SrF₁₀ polyhedra and isolated SrF₈ polyhedra, respectively. Magnetic property measurements on Sr₂Fe₂F₁₀(H₂O) reveals an antiferromagnetic order at T_N of ~2.5 K with a Weiss temperature (θ) of -61.51 K.

• Kyungpook Mathematical Journal
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• v.46 no.2
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• pp.219-229
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• 2006

Using the integral average method, we establish some oscillation criteria for the nonlinear differential equation with damped term $$a(t)|{x}^{\prime}(t)|^{\sigma-1}{x}^{\prime}(t)^{\prime}+p(t)|{x}^{\prime}(t)|^{\sigma-1}{x}^{\prime}(t)+q(t)f(x(t))=0,\;{\sigma}>1$$, where the functions $a,\;p$ and $q$ are real-valued continuous functions defined on $[t_o,{\infty})$ with $a(t)>0,\;f(x){\in}C^1(\mathbb{R})$ and $\frac{f^{\prime}(u)}{|f^{({\sigma}-1)/{\sigma}}(u)|}{\geq}k>0$ for $u{\neq}0$.

• Fashion & Textile Research Journal
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• v.19 no.5
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• pp.653-660
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• 2017

Recently, consumers' evaluation and purchase of online design has been increasing due to the popularization of designing through personal computers, but there has not been enough studies on consumers' brain wave responses depending on the change of PC monitor's color. Therefore, this study investigated how brain waves changed when different background colors with gray patterns were presented through PC monitors. Six background colors with same tone of slightly low saturation were selected, including ivory, yellow, pink, green, blue and pure white as a base color. The brightness and characteristics of color used were analyzed using the luminance meter and color scales. Brain wave was measured by EEG measurement equipment. Brain wave measurement was carried out with 9 subjects at 6 points: F3, F4, T3, T4, O1, and O2. Stimuli were shown for 15 seconds each and black screens were displayed for 15 seconds between each stimulus. As results, the brain waves at O1 responded sensitively by different background colors, followed by F4 and T4. Brain index such as 'RT', 'RA', 'RG', 'RSA', and 'RAHB' showed significant differences depending on the background color at O1, whereas 'RST' differed at F4. Yellow and blue backgrounds pair was the only stimuli that showed significant differences in six brain indices mentioned. Yellow background had higher value of 'RG' at O1 and higher 'RST' at F4, indicating yellow background enhanced concentration. Blue background activated 'RT', 'RA', 'RSA', 'RAHB' at O1, meaning blue background induced calm and stable state.