• Archives of Plastic Surgery
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• v.41 no.4
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• pp.317-324
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• 2014

Background Burn infliction techniques are poorly described in rat models. An accurate study can only be achieved with wounds that are uniform in size and depth. We describe a simple reproducible method for creating consistent burn wounds in rats. Methods Ten male Sprague-Dawley rats were anesthetized and dorsum shaved. A 100 g cylindrical stainless-steel rod (1 cm diameter) was heated to $100^{\circ}C$ in boiling water. Temperature was monitored using a thermocouple. We performed two consecutive toe-pinch tests on different limbs to assess the depth of sedation. Burn infliction was limited to the loin. The skin was pulled upwards, away from the underlying viscera, creating a flat surface. The rod rested on its own weight for 5, 10, and 20 seconds at three different sites on each rat. Wounds were evaluated for size, morphology and depth. Results Average wound size was $0.9957cm^2$ (standard deviation [SD] 0.1845) (n=30). Wounds created with duration of 5 seconds were pale, with an indistinct margin of erythema. Wounds of 10 and 20 seconds were well-defined, uniformly brown with a rim of erythema. Average depths of tissue damage were 1.30 mm (SD 0.424), 2.35 mm (SD 0.071), and 2.60 mm (SD 0.283) for duration of 5, 10, 20 seconds respectively. Burn duration of 5 seconds resulted in full-thickness damage. Burn duration of 10 seconds and 20 seconds resulted in full-thickness damage, involving subjacent skeletal muscle. Conclusions This is a simple reproducible method for creating burn wounds consistent in size and depth in a rat burn model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.645-653
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• 2017

In bone tissue engineering, polycaprolactone (PCL) is one of the most widely used biomaterials in the manufacturing of scaffolds as a synthetic polymer having biodegradability and biocompatibility. The strut width in the fabrication of scaffolds is an important part of tissue regeneration in in-vitro and in-vivo experiments, because it affects not only the pore size but also the porosity. In this study, we used polymer deposition system (PDS) and design of experiments (DOE) to explore the optimal process conditions to achieve a systematic and efficient scaffold manufacturing process, using temperature, pressure, scan velocity, and nozzle tip height as the parameters for the experiments. The aim of this research was to fabricate a 3D PCL scaffold having a uniform strut width of $150{\mu}m$ using DOE; it was proved that the strut width was constant in all the experimental groups by fabricating the PCL scaffolds according to various pore patterns as well as one pore pattern.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.377-377
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• 2012

Microprocessor technology now relies on copper for most of its electrical interconnections. Because of the high diffusivity of copper, Atomic layer deposition (ALD) $TaN_x$ is used as a diffusion barrier to prevent copper diffusion into the Si or $SiO_2$. Another problem with copper is that it has weak adhesion to most materials. Strong adhesion to copper is an essential characteristic for the new barrier layer because copper films prepared by electroplating peel off easily in the damascene process. Thus adhesion-enhancing layer of cobalt is placed between the $TaN_x$ and the copper. Because, cobalt has strong adhesion to the copper layer and possible seedless electro-plating of copper. Until now, metal film has generally been deposited by physical vapor deposition. However, one draw-back of this method is poor step coverage in applications of ultralarge-scale integration metallization technology. Metal organic chemical vapor deposition (MOCVD) is a good approach to address this problem. In addition, the MOCVD method has several advantages, such as conformal coverage, uniform deposition over large substrate areas and less substrate damage. For this reasons, cobalt films have been studied using MOCVD and various metal-organic precursors. In this study, we used $C_{12}H_{10}O_6(Co)_2$ (dicobalt hexacarbonyl tert-butylacetylene, CCTBA) as a cobalt precursor because of its high vapor pressure and volatility, a liquid state and its excellent thermal stability under normal conditions. Furthermore, the cobalt film was also deposited at various $H_2/NH_3$ gas ratio(1, 1:1,2,6,8) producing pure cobalt thin films with excellent conformality. Compared to MOCVD cobalt using $H_2$ gas as a reactant, the cobalt thin film deposited by MOCVD using $H_2$ with $NH_3$ showed a low roughness, a low resistivity, and a low carbon impurity. It was found that Co/$TaN_x$ film can achieve a low resistivity of $90{\mu}{\Omega}-cm$, a low root-mean-square roughness of 0.97 nm at a growth temperature of $150^{\circ}C$ and a low carbon impurity of 4~6% carbon concentration.

• Science of Emotion and Sensibility
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• v.19 no.4
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• pp.3-12
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• 2016

The aim of this study is to find the optimal combination dyeing condition for the enhancement of dye uptake and union dyeing of the composite material fabric made of triacetate and quick drying PET blended yarn. For the experiment, fabrics were one-bath combination dyed using the mixed dye of E-type disperse dye(C.I Disperse red 50) and S-type disperse dye(C.I. Disperse red 92) to measure dyed fabric's dye exhaustion, dye uptake, color and color difference according to the diverse conditions including dying temperature, time and mixed ratio of the dye. Dye equilibrium of combination dyeing occurred in $100^{\circ}C$, but by comparing dyed fabrics' K/S value and surface color, it was found that $120^{\circ}C$ was where the manifestation of color of triacetate and quick drying PET was identical. Mixed dye exhaustion and dye uptake merely changed as dyeing time increased, but color became more uniform. Therefore, it can be concluded that by using combination dyeing method, and by using the mixed dye which the mixing ratio of S-type dye and E-type dye is appropriately controlled, dye uptake can be improved compared to using single dyeing regardless of the color of E-type dye.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.285-294
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• 1994

Some supported gold catalysts were prepared by impregnation and coprecipitation methods. Effect of gold addition and active sloe formation were studied by investigating particle sizes of gold, amounts of oxygen adsorbed, adsorption properties of CO and NO, and reduction and oxidation properties, etc.. The gold particles of the catalyst by impregnation were irregular and very large as 30~100 nm, but those by coprecipitation were uniform and ultra-fine as about 4 nm. On $Au/Al_2O_3$ catalyst, the addition of gold to inactive $Al_2O_3$ caused the decomposition of $N_2O$, and CO was not irreversibly adsorbed while $O_2$ was atomically and irreversibly adsorbed. The adsorption sites of oxygen were attributed to the active sites which were restricted to the circumference of hemispherical gold particle-support interface rather than all atoms on the surface of gold particle. Also, CO was reversibly and irreversibly adsorbed on $Al_2O_3$ at low temperature, and the addition of gold weakened both reversible and irreversible adsorptions. The affinity for CO on $Au/Co_3O_4$ catalyst decreased conspicuously compared to $Co_3O_4$. The effect of gold addition did not appear in reduction step but did remarkably in reoxidation step; the added gold promoted the reoxidation of the reduced cobalt atoms.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.466-470
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• 2008

The objective of this study is to convert methane into hydrogen using a nanoporous catalyst in the $CO_2$ containing syngas generated from the gasified waste. For the purpose, $Ni/Al_2O_3$ catalyst was prepared with the one-pot method. According to analyses of the catalyst, three dimensionally linked sponge shaped particles were created and the prepared nanoporous catalysts had larger surface area and smaller particle size and more uniform pores compared to the sphere shaped commercial catalyst. The catalyst for reforming reaction gave the highest $CH_4$ conversion of 91%, and $CO_2$ conversion of 92% when impregnated with 16 wt% of Ni at the reaction temperature of $750^{\circ}C$. At that time, the prepared catalyst remarkably improved the $CH_4$ and $CO_2$ conversion up to 20% compared to the commercial one.

• Journal of Life Science
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• v.27 no.2
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• pp.211-216
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• 2017

This study aims to reduce the production cost of mushrooms and therefore boost the income of mushroom producers. The addition of a 10% concentration of herb medicine refuse was adequate for promoting mycelium growth in Flammulina velutipes. A moisture content of 60% in the culture medium was adequate for promoting hyphal growth. The optimum temperature and humidity were $16^{\circ}C$ and 70%-85%, respectively. The average yield of Flammulina velutipes fruting body per 1,100 ml bottle was 275-282 g, which is similar to that of the control. The outbreak of diseases such as mildew and bacterial blotch in mushroom was never observed in the bottle treated with herb medicine refuse. Fewer deformed and second-class quality mushrooms were observed than in the control group. Deviation reduced, and mushroom growth was observed to be significantly uniform. The winter mushroom had a white fruiting body with a hemispherical shape. The diameter of the mushroom cap was 9.2-9.3 mm, stipe length was 12.7-12.8 cm, and thickness was 3.3-3.4 mm; these were almost the same as those in the control group. The partial hardness of winter mushrooms in both the experimental and the control groups showed that the stipe ($54.6-57.3g/cm^2$) is a little harder than the mushroom cap ($46.8-47.6g/cm^2$). The calories and nutrients per 100 g of mushrooms in the control and samples were similar to each other.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.10-18
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• 2018

The primary purposes of this study are to understand a fundamental aspect of current uniformity around a reinforcing bar (rebar) in cement mortar, and to develop an accurate monitoring method in a wet-dry cycling process with the alternative current (AC) impedance method. Three cement mortar specimens with two embedded rebars were prepared in the laboratory. As a main variable, the distance between two rebars was designed to be 10, 20 and 30 mm with the same thickness of 20 mm. To simulate the corrosion of rebars in concrete structures in a marine environment, three cement mortar specimens were exposed to 15 wet-drying cycles (24-hour-immersion in seawater and 48-hour-drying in a room temperature) in the laboratory. It was observed that the potential level shifted to a noble value during corrosion potential monitoring, which is attributed to acceleration of dissolved oxygen diffusion at the drying process. AC impedance was measured in a frequency range from 100 kHz to 1 mHz on a wet-drying process. A theoretical model was proposed to explain the interface condition between the rebars and cement mortar by using the equivalent circuit consisting of a solution resistance, a charge transfer resistance and a CPE (constant phase element). It was observed that the diffusion impedance appeared in a low frequency range as corrosion of rebars progresses. At the drying stage of the wet-drying cycles, the currents line for monitoring tended to be non-uniform at the interface of rebar/mortar, being phase shift, ${\theta}$, close to $-45^{\circ}$.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.649-656
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• 2002

In situ patterned zinc oxide thin films were prepared by precipitation of Zn(NO$_3$)$_2$ aqueous solution containing urea and by microcontact printing using Self-Assembled Monolayers(SAMs) on A1/SiO$_2$/Si substrates. The visible precipitation of Zn(OH)$_2$ that was formed in the Zn(NO$_3$)$_2$ aqueous solution containing urea was enhanced with an increase of the reaction temperature and the amount of urea. As the reaction time of Zn(NO$_3$)$_2$ with urea was prolonged, the thickness and grain size of Zn(OH)$_2$ thin layers were increased, respectively. The optimum precipitation condition was at 80$\^{C}$ for 1 h for the solution with the ratio of Zn(NO$_3$)$_2$ to urea of 1 : 8. Homogeneous ZnO thin films were fabricated by the heat treatment of 600$\^{C}$ for 1 h of Zn(OH)$_2$ precipitation on Al/SiO$_2$/Si substrate. This was available to the in-situ patterned ZnO thin films with uniform grain size. Hydrophobic SAM, Octadecylphosphonic Acid(OPA) and hydrophilic SAM, 2-Carboxyethylphosphonic Acid(CPA) were applied on the Al/SiO$_2$/Si substrate by microcontact printing method. In situ patterned ZnO thin film was successfully prepared by the heat treatment of Zn(OH)$_2$ precipitated on the surface of hydrophilic SAM, CPA.

• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.7-13
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• 2007

We synthesized and investigated $La_{0.75}Sr_{0.25}FeO_3$ by Glycine Nitrate Process(GNP) method used as cathode materials for SOFC(solid oxide fuel cell). Optimized amount of glycine is 3.17 mol. ICP elemental composition analysis indicated that the stoichiometry of the synthesized powders have nearly nominal values. SEM images and XRD patterns reveal that the synthesized powder has uniform size distribution and high degree of crystallinity. The sample powders were isostatically pressed to form a pellet. The green body was sintered at $1200^{\circ}C$ and the relative density of the sintered specimens were measured by Archimedes mettled. We measured electrochemical performance of LSF by AC impedance spectroscopy. Resistance of LSF shows lower value than that of LSM throughout all temperature region. The anode-supported solid oxide fuel cell showed a performance of $342mW/cm^2(0.7V,\;488mA/cm^2)$ at $750^{\circ}C$. The electrochemical characteristics of the single cell were examined by at impedance method.