• Korean Journal of Metals and Materials
• /
• v.49 no.6
• /
• pp.493-497
• /
• 2011

The basic properties and electrical characteristics of sputtering films deposited with a commercial cast target and spark plasma sintering (SPS) were compared and analyzed. The results, revealed that, the Al film prepared by heating at $60^{\circ}C/min$ (SPS process) showed a specific resistance similar to the commercial cast Al film. In addition, the results of XRD, SIMS and TEM, showed that there was not much difference in the crystal structure and impurities between the two films. Consequently, the SPS Al target was found to have properties quite similar to the commercial one and it is expected to be applied in future research to the metal wiring material for semiconductor/display devices.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.4_2
• /
• pp.509-515
• /
• 2021

In this study, a pressure vessel for a heat pipe was fabricated by bonding a metal thin film using a polymer compound sheet. In order to confirm the applicability of the experimentally manufactured copper material thin heat pipe of 0.6 mm or less, the pressure resistance and effective thermal conductivity for pressure generated according to the type of the working fluid of the heat pipe were evaluated to suggest the commercialization potential of the thin heat pipe. As a result of evaluating the pressure resistance and effective thermal conductivity performance of the thin heat pipe, the following conclusions were drawn. 1) Using a PEEK-based polymer compound sheet, it was possible to fabricate a pressure vessel for a thin heat pipe with a pressure resistance of up to 1.0 MPa by bonding a copper thin film, and the possibility of commercialization was confirmed at a temperature below 120 ℃. 2) In the case of the effective thermal conductivity performance evaluation test, the effective thermal conductivity of ethanol was higher than that of FC72 and Novec7000, and in the case of ethanol, the maximum effective thermal conductivity was 2,851 W/mK at 3.0 W of heating.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.5
• /
• pp.425-430
• /
• 2022

Concrete used for the foundation of high-rise buildings is often placed through in an integrated pouring to ensure construction efficiency and quality. However, if concrete is placed integrally, there is a high risk of temperature cracking during the hydration reaction, and it is necessary to determine the optimal mixing design of high-performance, high-durable concrete through the replacement of the admixture. In this study, experiments on salt damage, carbonation, and sulfate were conducted on the specimen manufactured from the optimal high-performance low-heating concrete combination determined in the author's previous study. The resistance of the cement matrix to chlorine ion diffusion coefficient, carbonation coefficient, and sulfate was quantitatively evaluated. In the terms of compression strength, it was measured as 141% compared to the structural design standard of KCI at 91 days. Excellent durability was expressed in carbonation and chlorine ion diffusivity performance evaluation. In particular, the chlorine ion diffusion coefficient, which should be considered the most strictly in the marine environment, was measured at a value of 4.09×E-12m²/y(1.2898×E-10m²/s), and is expected to be used as a material property value in salt damage durability analysis. These results confirmed that the latent hydroponics were due to mixing of the admixture and high resistance was due to the pozzolane reaction.

• Journal of Animal Science and Technology
• /
• v.64 no.6
• /
• pp.1245-1258
• /
• 2022

This study was conducted to determine the effect of natural ingredient seasoning on the reduction of heterocyclic amine (HCA) production that may occur when pork belly is cooked at a very high temperature for a long time. Pork belly seasoned with natural ingredients, such as natural spices, blackcurrant, and gochujang, was cooked using the most common cooking methods, such as boiling, pan fry, and barbecue. HCAs in pork belly were extracted through solid-phase extraction and analyzed via high-performance liquid chromatography. For short-term toxicity, a mouse model was used to analyze weight, feed intake, organ weight, and length; hematology and serology analysis were also performed. Results revealed that HCAs formed only when heating was performed at a very high temperature for a long time, not under general cooking conditions. Although the toxicity levels were not dangerous, the method showing the relatively highest toxicity among various cooking methods was barbecue, and the natural material with the highest toxicity reduction effect was blackcurrant. Furthermore, seasoning pork belly with natural materials containing a large amount of antioxidants, such as vitamin C, can reduce the production of toxic substances, such as HCAs, even if pork belly is heated to high temperatures.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.64 no.5
• /
• pp.9-16
• /
• 2022

Syngas, also known as synthesis gas, synthetic gas, or producer gas, is a combustible gas mixture generated when organic material (biomass) is heated in a gasifier with a limited airflow at a high temperature and elevated pressure. The present research was aimed at modifying the existing LPG engine generator for fully operated syngas. During this study, the designed gasifier-powered woodchip biomass was used for syngas production to generate power. A 6.0 kW LPG engine generator was modified and tested for operation on syngas. In the experiments, syngas and LPG fuels were tested as test fuels. For syngas production, 3 kg of dry woodchips were fed and burnt into the designed downdraft gasifier. The gasifier was connected to a blower coupled with a slider to help the air supply and control the ignition. The convection cooling system was connected to the syngas flow pipe for cooling the hot produce gas and filtering the impurities. For engine modification, a customized T-shaped flexible air/fuel mixture control device was designed for adjusting the correct stoichiometric air-fuel ratio ranging between 1:1.1 and 1.3 to match the combustion needs of the engine. The composition of produced syngas was analyzed using a gas analyzer and its composition was; 13~15 %, 10.2~13 %, 4.1~4.5 %, and 11.9~14.6 % for CO, H₂, CH₄, and CO₂ respectively with a heating value range of 4.12~5.01 MJ/Nm³. The maximum peak power output generated from syngas and LPG was recorded using a clamp-on power meter and found to be 3,689 watts and 5,001 watts, respectively. The results found from the experiment show that the LPG engine generator operated on syngas can be adopted with a de-ration rate of 73.78 % compared to its regular operating fuel.

• Journal of Electrochemical Science and Technology
• /
• v.13 no.3
• /
• pp.390-397
• /
• 2022

The use of microwaves as the energy source for synthesis and sintering of ceramics offers substantial advantages compared to conventional gas-fired and electric resistance furnaces. Benefits include much shorter processing times and reaching the sintering temperature more quickly, resulting in superior final product quality. Most oxide ceramics poorly interact with microwave irradiation at low temperatures; thus, a more complex setup including a susceptor is needed, which makes the whole process very complicated. This investigation pursued a new approach, which enabled us to use microwave irradiation directly in poorly coupled oxides. In many solid-state electrochemical devices, the support is either metal or can be reduced to metal. Metal powders in the support can act as an internal susceptor and heat the entire cell. Then sufficient interaction of microwave irradiation and ceramic material can occur as the sample temperature increases. This microwave heating and exothermic reaction of oxidation of the support can sinter the ceramic very efficiently without any external susceptor. In this study, yttria stabilized zirconia (YSZ) and a Ni-YSZ cermet support were used as an example. The cermet was used as the support, and a YSZ electrolyte was coated and sintered directly using microwave irradiation without the use of any susceptor. The results were compared to a similar cell prepared using a conventional electric furnace. The leakage test and full cell power measurement results revealed a fully leak-free electrolyte. Scanning electron microscopy and density measurements show that microwave sintered samples have lower open porosity in the electrode support than conventional heat treatment. This technique offers an efficient way to directly use microwave irradiation to sinter thin film ceramics without a susceptor.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.2
• /
• pp.66.3-67
• /
• 2021

Low-mass stars form by the gravitational collapse of dense molecular cores. Observations and theories of low-mass protostars both suggest that accretion bursts happen in timescales of ~100 years with high accretion rates, so called episodic accretion. One mechanism that triggers accretion bursts is infalling fragments from the outer disk. Such fragmentation happens when the disk is massive enough, preferentially activated during the embedded phase of star formation (Class 0 and I). Most observations and models focus on the gas structure of the protostars undergoing episodic accretion. However, the dust and ice composition are poorly understood, but crucial to the chemical evolution through thermal and energetic processing via accretion burst. During the burst phase, the surrounding material is heated up, and the chemical compositions of gas and ice in the disk and envelope are altered by sublimation of icy molecules from grain surfaces. Such alterations leave imprints in the ice composition even when the temperature returns to the pre-burst level. Thus, chemical compositions of gas and ice retain the history of past bursts. Infrared spectral observations of the Spitzer and AKARI revealed a signature caused by substantial heating, toward many embedded protostars at the quiescent phase. We present the AKARI IRC 2.5-5.0 ㎛ spectra for embedded protostars to trace down the characteristics of accretion burst across the evolutionary stages. The ice compositions obtained from the absorption features therein are used as a clock to measure the timescale after the burst event, comparing the analyses of the gas component that traced the burst frequency using the different refreeze-out timescales. We discuss ice abundances, whose chemical change has been carved in the icy mantle, during the different timescales after the burst ends.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.4
• /
• pp.560-567
• /
• 2023

This study is part of the research on fire-resistant materials to prepare for changing fire behavior, oyster shell and egg shell, which are natural calcium carbonate materials, were substituted as fine aggregates. The purpose of this study was to evaluate the strength and fire resistance performance according to the substitution rate, and to provide data for use as fire resistance material. Oyster shells and egg shells were substituted with 10~50 % of the fine aggregate, respectively, and tested for strength and Simplified heating according to the KS test method. Although the strength of OS was measured to be higher than that of ES, the backside temperature was also measured to be higher. As a result, it is recommended to use fireproof boards with OS where strength performance is required, such as explosive fires, Where high fire resistance performance is required, such as high-temperature fires over 1000 ℃, fireproof boards with ES can be selected according to the application.

• Journal of the Korean Wood Science and Technology
• /
• v.52 no.2
• /
• pp.118-133
• /
• 2024

The sapwood portion of fast-growing teak is mostly ignored due to its inferior quality. One of the possibilities for utilizing sapwood waste is to convert it into activated carbon that has good adsorption capabilities. The raw materials used in this research were sapwood of 14-year-old fast-growing teak sapwood (FTS) waste, which was taken from three trees from community forests in Wonosari, Gunungkidul, Yogyakarta Special Region. FTS waste was taken from the bottom of the tree up to a height of 1.3 m. The activation process is conducted with an activation temperature of 750℃, 850℃, and 950℃. The heating duration consists of three variations: 30 min, 60 min, and 90 min. The quality evaluation parameters of activated carbon include yield, moisture content, volatile matter content, ash content, fixed carbon content, adsorption capacity of benzene, adsorption capacity of methylene blue, and adsorption capacity of iodine. The results showed that the activated carbon produced had the following quality parameters: yield of 75.61%; moisture content of 1.27%; volatile matter content of 9.98%; ash content of 5.43%; fixed carbon content of 84.58%; benzene absorption capacity of 8.58%; methylene blue absorption capacity of 87.73 mg/g; and iodine adsorption capacity of 948.19 mg/g. It can be concluded that activated carbon from FTS waste has good iodine adsorption, which fulfilled the SNI 06-3730-1995 quality standard. Due to the iodine adsorption ability of FTS waste activated carbon, the conversion of FTS waste to activated carbon is categorized as a potential method to increase the value of this material.

• Journal of the Korean Society of Food Culture
• /
• v.5 no.1
• /
• pp.59-75
• /
• 1990

The tzeam is the one of steaming cook that boiled the main material of poultry. meat and the sub-material of vegetables. It is always setted on the main-table in above seven chup ban sang and also kyoja sang. In this thesis, according to the kinds of tzeam in the main material of poultry, meat was to analysis reference frequency to them the materials, the measuring unit of materials, the terms of cooking and kitchen utensil by 47 books published in Korea from 1420 to 1987. 1. It was 37 kinds of tzeam in the main material of poultry, meat. 2. Materials were classified into the main-material, sub-materials, seasioning and decorations. 3. There were 43 kinds of measuring units, of them 18 kinds were for volume, 12 kinds were for quantity, 4 kinds were for length and the rest measuring units were 9 kinds. 4. There were 26 kinds of kitchen utensil for cooking. They were mainly used a hab 1 rice ball with lids, and castles (cast iron castle). 5. There were 27 kinds of cooking terms. The terms of them, 11 kinds were for heating methods, 16 terms of them were for the cutting process.