• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.157-164
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• 2008

The temperature-entropy diagram of water or vapor displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. On general T-s chart of water, there are temperature, pressure, quality, specific volume, specific enthalpy, specific entropy. However, various state and process values besides above properties can be plotted on T-s diagram. In this study, we developed the software drawing twenty six kinds of properties, that is temperature, pressure, quality, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, coefficient of viscosity, kinematic coefficient of viscosity, thermal conductivity, prandtl number, ion product, static dielectric constant, isentropic exponent, velocity of sound, joule-thomson coefficient, pressure coefficient, volumetric coefficient of expansion, isentropic compressibility, and isothermal compressibility. Also, this software can analyze and print the system values of mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, and reversible work. Additionally, this software support the functions such as MS-Power Point.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.42-48
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• 1999

Three experiments were conducted to develop and test equations for predicting carcass composition. In the first study using 52 d-old Cobb ${\times}$ Cobb male broilers, twenty four carcasses were selected from 325 processed birds based upon visual appraisal for abdominal fat (low, medium, high) and assayed for specific gravity (SG), dry matter (DM), fat, protein, and ash. In experiment 2, 120 birds were fed rations containing 2 caloric densities (2,880 and $3,200kcal\;ME_n/kg$ diet) and assayed as described above on weeks 2,3,4,5, and 6. Carcass fat was elevated (p < 0.05) with increased caloric density. In both studies predictive variables were significantly correlated with chemically determined carcass fat, protein, and ash contents. Pooled across the 2 studies, data were used to form SG, DM, and or age based equations for predicting carcass composition. Results were tested in experiment 3, where 576 birds reared to 49-d consumed either 2,880, 3,200, or $3,574kcal\;ME_n/kg$ diet while exposed to constant $24^{\circ}C$ or cycling 24 to $35^{\circ}C$ ambient temperatures. Both dietary and environmental effects impacted (p < 0.05) carcass composition. The fat content analyzed chemically was enhanced from 12.4 to 15.7%, and predicted fat was also elevated from 13.4 to 14.8% with increasing caloric density. Heat distress reduced (p < 0.05) analyzed carcass protein (18.9 vs 18.3%) and predicted protein (18.2 vs 17.5%). Predicted equation values for carcass fat, protein, ash, and energy were correlated with the chemically analyzed values at r=0.96, 0.77, 0.86, and 0.79, respectively. Results suggest that prediction equations based on DM and SG may be used to estimate carcass fat, protein, ash, and energy contents of broilers consuming diets that differ in caloric density (2,800 to $3,574kcal\;ME_n/kg$) and for broilers exposed to either constant ($24^{\circ}C$) or cycling high (24 to $35^{\circ}C$) ambient temperatures during 49-d rearing period tested in the present study.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.171-176
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• 2017

The nitrogen plasma thermal decomposition and recovery processes for $CHClF_2$ (Chlorodifluoromethane) refringent were investigated. The steam generator was employed to provide superheated steam reactor, supporting the decomposition reaction of refringent. Even though over 94% of R-22 was decomposed on the condition of 60 A and 9.0 kW, a higher power and specific energy density were required to achieve the complete combustion of carbon materials. In the operating condition of 60 A and 12.6 kW, $O_2$/R-22 ratio in reactants gases are a key factor to obtain much higher decomposition ratio during process. It should be noticed that injecting the mixture of $O_2$ and air was much more effective than injecting the air consisting equivalent $O_2$ amount.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.489-494
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• 2004

In this paper, we investigated impurities content and thermal properties showing by changing the content of carbon black which is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens was measured by ICP-AES(Inductively Coupled Plasma Atomic Emission Spectrometer), and density of specimens were measured by density meter. And then heat capacity(${\Delta}H$) and melting temperature(Tm), specific heat(Cp) were measured by DSC(Differential Scanning Calorimetry). The dimension of measurement temperature was $0[^{\circ}C]\;to\;200[^{\circ}C]$, and rising temperature was $4[^{\circ}C/min]$. Impurities content was highly measured according to increasing the content of carbon black from this experimental result also density was increased according to these properties. Specially, impurities content values of the A1 and A2 of existing resins were measured more than 4000[ppm]. Heat capacity, melting temperature, and specific heat from the DSC results were simultaneously decreased according to increasing the content of carbon black. Because metallic impurities of carbon black having Fe, Co, Mn, A1 and Zn are rapidly passed kinetic energy increasing the number of times breaking during the unit time with the near particles according to increasing vibration of particles by the applied heat energy.

• Journal of Biosystems Engineering
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• v.21 no.1
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• pp.84-93
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• 1996

Several paraffins(CnH2n +2) can be used as the thermal energy storage medium because of their large amount of latent heat and their flexibility of phase change temperature. But they have not been used in the thermal energy storage system because their long term stability have not been verified. Paraffins(CnH2n+2) which the values of n are 23, 24, 26 and 28 were selected for this experimental research. And this research was peformed to apply them to the practical systems. The results were summarized as follows. (1) The increase of phase change cycles had no effect on their phase change temperatures. (2) According as the values of n increased from 23 to 28, the specific heats of paraffins(CnH2n+2) increased, and were in the range of 0.47 0.75 ㎉/$kg^circ C$. (3) Thermal conductivities of them were in the range of 0.14 0.17 W/$m^circ C$. and specific gravities of them were in the range of 765800 kg/m3. (4) The density of paraffins was in the range of 765 800 kg/$m^circ C$ , and the density of solid phase was larger than that of liquid phase. (5) When the number of phase change cycles was 1, 500 cycles, the latent heat of paraffins was 90% of the initial value.

• Advances in Energy Research
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• v.7 no.1
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• pp.21-34
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• 2020

Energy storage devices have received a keen interest throughout the world due to high power consumption. A large number of research activities are being conducted on electrochemical double layer capacitors (EDLCs) because of their high power density and higher energy density. In the present study, an EDLC was fabricated using natural graphite based electrodes and ionic liquid (IL) based gel polymer electrolyte (GPE). The IL based GPE was prepared using the IL, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (1E3MITF) with the polymer poly(vinyl chloride) (PVC) and the salt magnesium trifluoromethanesulfonate (Mg(CF₃SO₃)₂ - MgTF). GPE was characterized by electrochemical impedance spectroscopy (EIS), DC polarization test, linear sweep voltammetry (LSV) test and cyclic voltammetry (CV) test. The maximum room temperature conductivity of the sample was 1.64 × 10^-4 Scm^-1. The electrolyte was purely an ionic conductor and the anionic contribution was prominent. Fabricated EDLC was characterized by EIS, CV and galvanostatic charge discharge (GCD) tests. CV test of the EDLC exhibits a single electrode specific capacitance of 1.44 Fg^-1 initially and GCD test gives 0.83 Fg^-1 as initial single electrode specific discharge capacitance. Moreover, a good stability was observed for prolonged cycling and the device can be used for applications with further modifications.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1191-1196
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• 2009

The T-s chart of air displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. In previous study, the software analyzing 31 kinds of values in water system and 32 kinds of values in air-conditioning system were developed. In this study, the software drawing 13 kinds of quantity of state on air properties as ideal gas and analyzing 25 kinds of values in any air system was developed. The 13 kinds of quantity of state on air properties are temperature, pressure, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, and velocity of sound, and the 25 kinds of values including 13 kinds are mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, reversible work, lost work, and relative humidity. The developed software can draw any range of chart and analysis any state or process on air system. Also, this supports various document-editing functions such as power point. We wish to this chart is a help to design, analysis, and education in air system field.

• Korean Journal of Materials Research
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• v.31 no.2
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• pp.68-74
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• 2021

Zinc-ion Batteris (ZIBs) are recently being considered as energy storage devices due to their high specific capacity and high safety, and the abundance of zinc sources. Especially, ZIBs can overcome the drawbacks of conventional lithium ion batteris (LIBs), such as cost and safety issues. However, in spite of their advantages, the cathode materials under development are required to improve performance of ZIBs, because the capacity and cycling stability of ZIBs are mainly influenced by the cathode materials. To design optimized cathode materials for high performance ZIBs, a novel manganese oxide (MnO2) coated graphite sheet is suggested herein with improved zinc-ion diffusion capability thanks to the uniformly decorated MnO2 on the graphite sheet surface. Especially, to optimize MnO2 on the graphite sheet surface, amounts of percursors are regulated. The optimized MnO2 coated graphite sheet shows a superior zinc-ion diffusion ability and good electrochemical performance, including high specific capacity of 330.8 mAh g-1 at current density of 0.1 A g-1, high-rate performance with 109.4 mAh g-1 at a current density of 2.0 A g-1, and remarkable cycling stability (82.2 % after 200 cycles at a current density of 1.0 A g-1). The excellent electrochemical performance is due to the uniformly decorated MnO2 on the graphite sheet surface, which leads to excellent zinc-ion diffusion ability. Thus, our study can provide a promising strategy for high performance next-generation ZIBs in the near future.

• Transactions on Electrical and Electronic Materials
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• v.8 no.4
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• pp.182-187
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• 2007

The use of the pulsed electro acoustic (PEA) method allowed us to perform the direct observations of spatio-temporal charge distributions in Electric double layer capacitors (EDLCs) based on polarizable nanoporous carbonaceous electrode. The negative charge density became the maximum, about $205C/m^3$ at the region where was near to collector layer in EDLCs for case $V_{DC}=2.5V$, while the positively charged density became the maximum, about $61.1C/m^3$ at the region where it was located around the cathode layer. The performance of the best sample was found to be better in terms of the charge density (Cs) and specific energy ($E_s$) with a maximum value of ${\sim}8.4F/g$ and 26 Wh/kg. The $C_s$ obtained from the PEA method agreed well with that from the energy conversion method. The PEA measurement used here is a very useful method to quantitively investigates the spatio-temporal charge distribution in EDLCs.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.2
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• pp.91-95
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• 2009

To understand the effect of attachment substrate on the growth of benthic microalgae, we experimentally investigated the growth of benthic microalgae Nitzschia sp. (Jinhae Bay strain) with additions of glass beads in different sizes. The glass beads used in this study are 0.09-0.15 mm (G1), 0.25-0.50 mm (G2), 0.75-1.00 mm (G3) and 1.25-1.65 mm (G4). No addition of glass beads used as controls. Highest specific growth rate (0.37/day) and maximum cell density ($9,232{\pm}840$ cells/mL) of Nitzschia sp. showed at the smallest glass beads (G1), and the specific growth rate and maximum cell density were decreasing with increasing size of glass beads (specific growth rate and maximum cell density of G4 was 0.24/day and $6,397{\pm}524$ cells/mL, respectively). Moreover, specific growth rate of the control experiment (0.23/day) was significantly lower than their of G1 to G3 experiment. The results indicated that the attachment substrate for benthic microalgae as Nitzschia sp. is important factor which affecting the growth rate as well as cell density. Therefore, the physiological experiment of benthic microalgae seems to be necessary to preliminary experiment, which is addition or not of the attachment suitable substrate and the grain size for the target species of benthic microalgae.