• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.759-766
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• 1994

The effect of additives on properties of unfired Al2O3-C bricks were investigated. The increase of carbon content and the addition of MgO or spinel improved the resistances against spalling and corrosion of unfired Al2O3-C bricks. Also, the oxidation resistance of unfired Al2O3-C brick was increased by adopting complex metals of Al and Si in spite of the increase of carbon content.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.438-439
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• 2006

We have used ITO/$Alq_3$/Al structure to study complex impedance in $Alq_3$ based organic light emitting diode. Equivalent circuit was analyzed in a device structure of ITO/$Alq_3$/Al by varying the thickness of $Alq_3$ layer from 60 to 400nm. The impedance results can be fitted using equivalent circuit model of parallel combination resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

• Journal of Pharmacopuncture
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• v.26 no.3
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• pp.238-246
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• 2023

Objectives: The purpose of this study was to evaluate the effectiveness of complex rehabilitation with and without acupuncture in a hospital setting. Methods: A randomized clinical trial was performed at Rehabilitation center "Kamenskoe Plato" in Almaty, Kazakhstan. 160 patients with Post COVID-19 condition were randomly equally divided into an acupuncture with complex rehabilitation methods and a only complex rehabilitation methods group in the period from March 1, 2022 to July 1, 2022. Either groups was performed for an 10-14 days period. The outcome measures were the Bartel index, the Borg scale, Modified Dyspnea Scale and the 6-minute walking test. Adverse events also were monitored and documented. Results: We found statistically significant improvement after the rehabilitation course with acupuncture in the all scales. And in the group without acupuncture, only on two scales: MDS and Borg scale. Conclusion: Rehabilitation with acupuncture is possible and effective in patients recovering from post-COVID-19. Our findings may be useful to guide clinicians taking care of patients with post-COVID-19.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.73-77
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• 2008

We have investigated dielectric polarization in organic light-emitting diodes using 8-hydroxyquinoline aluminum($Alq_3$) as an electron transport and emissive material. We analyzed the dielectric polarization of organic light-emitting diodes using characteristics of impedance and equivalent circuit of $ITO/Alq_3/Al$. Impedance characteristics was measured complex impedance Z and phase ${\theta}$ in the frequency range of $1{\times}40Hz\;to\;1{\times}10^8Hz$. We obtained complex electrical conductivity, dielectric constant, and loss tangent(tan${\delta}$) of the device at room temperature. And, we obtained the equivalent circuit of $ITO/Alq_3/Al$ through analyzing dielectric constant and dielectric loss tangent. From these analyses, we could interpret a conduction mechanism and dielectric polarization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.115-118
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• 2003

Complex impedances with frequency and voltage variation were analyzed in $ITO/Alq_{3}/Al$(100nm)/Al device structure. At low frequency, complex impedance is mostly expressed by resistive component, and at the high frequency by capacitive component. Also, we have evaluated resistance, capacitance and permittivity.

• Journal of Korea Foundry Society
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• v.18 no.4
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• pp.373-382
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• 1998

Particulate reinforced aluminum alloys produced by indirect squeeze casting are difficult to shape by cutting or milling. Therefore near net shape forming of complex shapes is of high economic and technical interest. The complex shape products of $SiC_p/6061$ Al composites are fabricated by the melt-stirring and indirect squeeze casting process. The mold temperatures are $200^{\circ}C$ and $300^{\circ}C$ and applied pressures are 70, 100, and 130 MPa. The volume fractions of the reinforcements are in the range of 5 vol% to 15 vol%. The reinforcement dispersion state are observed using on optical microscope. By employing observed results systematically a correlation is demonstrated among the microstructure, particles behavior, mechanical properties and processing parameters for an optimum melt-stirring(compocasting) and indirect squeeze casting process of MMCs. A procedure to establish the optimum squeeze casting of Al-MMCs is proposed.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.53-57
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• 2009

In order to treat the complex wastewater containing organic compound and solids, pre-treatment system associated with molecular separation process were investigated. The reductions of COD and turbidity were obtained after coagulation processes using Alum (Aluminium sulfate, $Al_2(SO_4)_2{\cdot}18H_{2}O$) and PACl (poly aluminium chloride as 17% $Al_{2}O_{3}$). The results of study were as follows: using variable dosage of Alum, COD removal was highest at 4,000 mg/l, and the reduction of COD and turbidity was 42% and 92%, respectively. The optimum coagulation would be effective at pH 7.3 than pH 9.0 by the addition of alum at a concentration of 6,000 mg/l and PACl was add at 4.25% in raw complex wastewater with 2,000 mg/l alum at pH 7.3, the reduction of COD was reduced by 32%. But coagulation aid experiments indicated that PACl would be more effective in sludge separation ability than COD removal efficiency.

• Kyungpook Mathematical Journal
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• v.54 no.2
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• pp.211-220
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• 2014

In the present investigation, by making use of the familiar concept of neighborhoods of analytic and multivalent functions, we prove several inclusion relations associated with the (n, ${\delta}$)-neighborhoods of certain subclasses of analytic functions of complex order, which are introduced here by means of the Al-Oboudi derivative. Several special cases of the main results are mentioned.

• Korean Journal of Crystallography
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• v.11 no.3
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• pp.173-175
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• 2000

Computational technique, based on the minimization of the crystal energy with respect to atomic coordinates, are shown to reproduce successfully complex crystal structure, in this case, strontium hexaaluminate magnetoplumbite, SrAl/sub 12/O/sub 19/. The experimental crystal structure and symmetry of the complex material is well reproduced with our potential models and some crystal physical properties are calculated.

• Journal of Korea Foundry Society
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• v.29 no.2
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• pp.64-69
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• 2009

In the present study the effect of cooling rate during solidification on the microstructural characteristics of Al-xAg (x = 31, 33, 35 at.%) in-situ binary eutectic composites has been investigated. To provide a wide range of cooling rate three different casting techniques, i.e. conventional casting, injection casting, and melt spinning have been used. The observed microstructure is very much dependent on the cooling rate. The fcc ${\alpha}$-Al and hcp $Ag_2Al$ phases exhibits an orientation of (111)Al//(0001)$Ag_2Al$, [1-10]Al//[11- 20]$Ag_2Al$. The microstructure of the melt-spun samples contains Widmanstatten structure resulting from solid-state transformation and nano scale two-phase structure resulting from solid-state phase separation. The microstructure of injection-cast samples contains eutectic structure and solid state phase-separated structure. On the other hand, conventional-cast samples exhibit a microstructure consisted of plate-type eutectic structure.