• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.159-164
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• 2022

The linear assignment problem (LAP) and linear bottleneck assignment problem (LBAP) has been unknown the algorithm to solve the optimal solution within polynomial-time. These problems are classified by NP-hard. Therefore, we can be apply metaheuristic methods or linear programming (LP) software package or Hungarian algorithm (HA) with O(m⁴) computational complexity. This paper suggests polynomial time algorithm with O(mn)=O(m²),m=n time complexity to LAP and LBAP. The select-delete method is simply applied to LAP, and the delete-select method is used to LBAP. For the experimental data without the unique algorithm can be apply to whole data, the proposed algorithm can be obtain the optimal solutions for whole data.

• Conservation Science in Museum
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• v.1
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• pp.61-74
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• 1999

Elemental analysis of 40 glass samples from the Northern Tomb and the Southern Tomb of Hwangnam-daech'ong No. 98 was performed. Fourteen compositions of each sample were analyzed quantitatively by SEM-EDS and glass samples were classified by multivariate analysis such as PCA. All of 40 samples were confirmed to be Na₂O-CaO-SiO₂ system with about 20% of Na₂O. Samples were classified into two groups by doing PCA on concentrations of 5 major elements(SiO₂, Al₂O₃, Na₂O, CaO and K₂O). Samples included in group I showed the concentration of Al₂O₃ is about 9.7% and that of CaO, about 2.2%. In group II, concentration of Al₂O₃ is about 3.2% and that of CaO, about 4.9%. Especially yellow grains embedded in sample No. 12 were shown to be PbSnO₃ by micro XRD, which was the first coloring material ever found in Korea. Lead isotope ratios of samples No. 12 and No. 17 which contained lead were measured by TIMS. The origin of lead was traced by means of multivariate analysis such as SLDA. The result showed that lead from southern China and southern Korea had been used for making glass.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.765-772
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• 1993

Two-dimensional potassium tetratitanate ($K_2Ti_4O_9$) and three-dimensional potassium hexatitanate ($K_2Ti_6O_{13}$) fibers have been prepared by the combined method consisting of the flux melting (1150$^{\circ}C$)-slow cooling (cooling rate = 5$^{\circ}C$/h) process from the starting raw materials of $K_2CO_3$, and $TiO_2$ with the flux of $K_2MoO_4$. It was found that the fiber growth reaction is strongly dependent upon the mole ratio of flux (F) to raw material (R), which is 7 : 3 (F : R) as for the optimum growth condition. Relatively long fibers (average length ${\thickapprox}$ 4 mm) with a mixture of $K_2Ti_4O_9$ (major) and $K_2Ti_6O_{13}$ (minor) could be obtained when the reaction was carried out for the $K_2MoO_4-$K_2O{\cdot}4TiO_2$ (F : R = 7 : 3) system, but for the $K_2$MoO_4$-$K_2O{\cdot}6TiO_2$ (F : R = 7: 3) one, only the short fibers with ${\thickapprox}$ 2 mm long could be grown as the mixed phase of $K_2Ti_6O_{13}$ and $K_2Ti_4O_9$.

• Journal of the Korean Chemical Society
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• v.18 no.4
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• pp.259-266
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• 1974

Isotopic experiments using $H_2O^{18}$ on the oxidation of V(III) in acid perchlorate by molecular oxygen were performed in the range pH 1.0 to 3.0. At pH < 2, where a rate equation of the form TEX>$ -\frac{d[V(III)]}{dt}=k_1\frac{[O_2][V(III)]}{[H^+]}$ is adequate, the tracer study clearly indicated that all the product vanadyl ion's ($VO^{2+}$) oxygen originated from the molecular oxygen. At pH > ~2, where a different rate expression of the form $-\frac{d[V(III)]}{dt}=K_2\frac{[O_2][V(III)]^2}{[Ht]^2}$is required, the isotopic experiment showed that half the vanadyl oxygen originated from the molecular oxygen. Considering the results of the isotopic study, a mechanism for the V(Ⅲ)-O2 reaction at pH < ~2, may be suggested as follows: The tracer results at pH > ~2 imply that the rate determining step may be $$ V_2(OH)_2^{4+} + O_2 \rightarrow 2VO^{2+} + H_2O_2$$ followed by $$V_2(OH)_2^{4+} + H_2O_2 \rightarrow 2VO^{2+} + 2H_2O$$ after establishing the equilibria V^{3+} + H_2O \leftrightarrow VOH^{2+} + H^+, and 2VOH^{2+}\leftrightarrow V_2(OH)_2^{4+}$$

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.575-578
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• 2004

The charging tendency of $Zn_2SiO_4:Mn^{2+}$ phosphor surface was modified in order to improve discharging characteristic of green cell in an ac-plasma display panel (ac-PDP). The Zinc-silicate ($Zn_2SiO_4:Mn^{2+}$) green-emitting phosphor was coated with magnesium oxide(MgO), which is viable to have positive charge on the surface. After fabricating the green cell with MgO-coated $Zn_2SiO_4:Mn^{2+}$, the electrical and optical properties in the cell were examined. It was found that the dynamic voltage margin could be increased while the address time was reduced. It may be ascribed to the change of charging tendency of $Zn_2SiO_4:Mn^{2+}$ phosphor by MgO coating, which makes it possible to stable wall-charge accumulation. When $Zn_2SiO_4:Mn^{2+}$ phosphor was coated with 1.3wt%-MgO, the address time was reduced 1.2 ${\mu}s$ and the address voltage lowered 25 V without any misfiring problem, compared to those of typical $Zn_2SiO_4:Mn^{2+}$ phosphor layer. The luminescence intensity of green cell using MgO-coated phosphor layer was also improved by 10%.

• Korean Journal of Materials Research
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• v.20 no.7
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• pp.379-384
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• 2010

The usual ceramic process of mixing and milling in state of oxides $ZrO_2$ and $CeO_2$ was adopted in this study in a wet process to manufacture Ce-TZP. $CeO_2$-$ZrO_2$ ceramics containing 8~20 mol% $CeO_2$ were made by heat treatment at $1250\sim1500^{\circ}C$ for 5hr. The maximum dispersion point of every slurry manufactured with a mixture of $ZrO_2$ and $CeO_2$ was neat at pH10. A stable slurry with average particle size of 90 nm can be manufactured when it is dispersed with the use of ammonia water and polycarboxylic acid ammonium. The sintered Ce-TZP ceramics manufactured with the addition of $CeO_2$ in a concentration of less than 10 mol% progressed to the fracture of the specimen due to the existence of a monoclinic phase of more than 30% at room temperature. More than 99% of the tetragonal phase was created for the sintered body with the addition of $CeO_2$ beyond 18 mol%, but the degradation of the mechanical properties on the entire specimen was brought about due to the $CeO_2$ existing in a percentage above 3%. Consequently, the optimal Ce-TZP level combined in the oxide state was identified to be 16 mol% of $CeO_2$ contents.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.334-340
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• 1997

Electric and dielectric properties of the $SrTiO_3$films have been studied. The influence of impurities on $SrTiO_3$ films was evaluated to reduce the leakage current density. Acceptor doping, with a small concentration of Fe or Cr, has led to a substantial improvement to $10^{-9}$ order in the leakage current density. The experimental results can be explained by a model in which oxygen vacancies are the key defects responsible for the leakage current. The $SrTiO_3$ film 200 nm in thickness with 5 mol% excess SrO fabricated in $Ar/O_2$ at $550^{\circ}C$ obtained the lowest leakage current density $1.0 {\times} 1.0 A/\textrm{cm}^2$. The improved results can be introduced into the capacitor dielectric of giga bit DRAM memories.

• Journal of Food Hygiene and Safety
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• v.20 no.2
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• pp.114-117
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• 2005

Although the removal efficiency of residual pesticides using tap water were ranged from -1.25 to $13.27\%$, the removal efficiencies of residual pesticides using both powder CaO and liquid CaO were $5.16\~l7.61,\;8.7\~41.59\%$, respectively. And those results showed much higher residual effect of the CaO washing than tap water washing. Natural CaO made by burning of scallop-shell considered to be a good reducing agent for pesticides. Furthermore, liquid CaO showed much higher removal efficiency than powder CaO. However, powder CaO also can be used as a good natural eliminator of pesticides in Mini-Tomato.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.68-69
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• 2005

BTO ($BaTiO_3$) thin film is one of the high dielectric materials for high-density dynamic random access memories (DRAMs) due to its relatively high dielectric constant. It is generally known that BTO film is difficult to be etched by plasma etching, but high etch rate with good selectivity to pattern mask was required. The problem of sidewall angle also still remained to be solved in plasma etching of BTO thin film. In this study, we first examined the patterning possibility of BTO film by chemical mechanical polishing (CMP) process instead of plasma etching. The sputtered BTO film on TEOS film as a stopper layer was polished by CMP process with the self-developed $BaTiO_3$- and $TiO_2$-mixed abrasives slurries (MAS), respectively. The removal rate of BTO thin film using the$ BaTiO_3$-mixed abrasive slurry ($BaTiO_3$-MAS) was higher than that using the $TiO_2$-mixed abrasive slurry ($TiO_2$-MAS) in the same concentrations. The maximum removal rate of BTO thin film was 848 nm/min with an addition of $BaTiO_3$ abrasive at the concentration of 3 wt%. The sufficient within-wafer non-uniformity (WIWNU%)below 5% was obtained in each abrasive at all concentrations. The surface morphology of polished BTO thin film was investigated by atomic force microscopy (AFM).

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.21-25
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• 2009

Using an evaporation system, $SiO_2$ was deposited as a buffer layer between a PET substrate and a ITO layer and then ITO/$SiO_2$/PET layers were annealed for 1.5 hours at the temperature of $180^{\circ}C$. Adhesion and electro-optical properties of ITO films were studied with thickness variance of a $SiO_2$ buffer layer. As a result of introduction of the $SiO_2$ buffer layer, sheet resistance and resistivity increased and a ITO film with optimum sheet resistance ($529.3{\Omega}/square$) for an upper ITO film of resistive type touch panel could be obtained when $SiO_2$ of $50{\AA}$ was deposited. And it was found that ITO films with $SiO_2$ buffer layer have higher transmittance of $88{\sim}90%$ at 550 nm wavelength than ITO films with no buffer layers and the transmittance was enhanced as $SiO_2$ thickness increased from $50{\AA}$ to $100{\AA}$. Adhesion property of ITO films with $SiO_2$ buffer layers became better than ITO films with no buffer layers and this property was independent of $SiO_2$ thickness variance ($50{\sim}100{\AA}$). By depositing a $SiO_2$ buffer layer of $50{\AA}$ on the PET substrate and sputtering a ITO thin film on the layer, a ITO film with enhanced adhesion, electro-optical properties could be obtained.