• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.125-126
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• 2023

Recently, heat island and dry island phenomena occur frequently due to land surface development and excessive energy consumption in urban areas. As a result, the surface temperature of the building and the entire temperature of its surroundings are increased, and as a result, the durability of the building is rapidly deteriorated. In order to suppress these causes, a method of maintaining the temperature of road heating wires was implemented as a temporary measure, but this did not predict climate change. Therefore, this study is a method to measure the compressive strength, density, and thermal conductivity of lightweight concrete using waste glass foam beads. After fabricating a simple chamber, the temperature and humidity of the inside and outside were measured with an Arduino device in consideration of external factors. Therefore, if waste glass foam beads made through proper mixing are constructed in the urban center, the quality of the urban can be improved.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.51-52
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• 2023

Recently, heat island and dry island phenomena occur frequently due to land surface development and excessive energy consumption in urban areas. As a result, the surface temperature of the building and the entire temperature of its surroundings are increased, and as a result, the durability of the building is rapidly deteriorated. In order to suppress these causes, a method of maintaining the temperature of road heating wires was implemented as a temporary measure, but this did not predict climate change. Therefore, this study is a method to measure the compressive strength, density, and thermal conductivity of light weight concrete using waste glass foam beads. After fabricating a simple chamber, the temperature and humidity of the inside and outside were measured with an Arduino device in consideration of external factors. Therefore, if waste glass foam beads made through proper mixing are constructed in the urban center, the quality of the urban can be improved.

• Archives of Plastic Surgery
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• v.40 no.4
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• pp.380-386
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• 2013

Background Xanthelasma palpebrarum (XP) is a benign disorder manifesting as yellowish cholesterol-laden plaques on the eyelids. This paper presents the outcomes in patients with XP who have undergone surgical excision as the main modality of treatment. Methods A retrospective review of patients who received surgery for xanthelasma palpebrarum from March 2007 to March 2011 was conducted. Patients were classified into four grades according to the location and extent of the lesion, with grade I being the mildest and grade IV being the most diffuse. Simple excision was performed in grade I and II lesions, while local flaps and skin grafts were performed in the more advanced grades. Results Ninety-five cases from March 2007 to March 2011 were included in this study. 66 cases (70%), were treated by simple excision. Twenty-four cases (25%) and 5 cases (5%) were treated by simple excision in combination with or without local flaps and skin grafts. In approximately 1/4 of the patients, orbicularis oris muscle involvement was observed. 4 patients (4.2%) developed scar contracture postoperatively, which required a secondary procedure. Recurrence was reported in 3 patients (3.1%). Otherwise. There were no other reports of major complications or disfigurement. Conclusions We found that for lesions involving the deep dermis and/or muscle, surgical excision was the most appropriate therapeutic option.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.187-190
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• 2014

Four excellent halogen-free biphosphonate flame retardants (EBDMP, EBDEP, MBDMP, MBDEP) were synthesized through polycondensation and Arbuzov rearrangement reactions without using any solvents. The products were characterized by ESI-MS, FT-IR and $^1H$ NMR. The application of EBDEP in polyurethane soft foam was studied and the results illustrated its excellent flame-proofing properties.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2092-2095
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• 2001

In this paper, the performance of a new alternative form of three-axis attitude estimation algorithm for a rigid body is evaluated via simulation for the situation where the observed vectors are the estimated baselines of a GPS antenna array. This method is derived based on a simple iterative nonlinear least-squares with four elements of quaternion parameter. The representation of quaternion parameters for three-axis attitude of a rigid body is free from singularity problem. The performance of the proposed algorithm is compared with other eight existing methods, such as, Transformation Method (TM), Vector Observation Method (VOM), TRIAD algorithm, two versions of QUaternion ESTimator (QUEST), Singular Value Decomposition (SVD) method, Fast Optimal Attitude Matrix (FOAM), Slower Optimal Matrix Algorithm (SOMA).

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.431-435
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• 1999

An organic precipitate flotation of Cd(Ⅱ) and Pb(Ⅱ) was investigated by the coprecipitation with lanthanum 8-hydroxyquinolinate. Trace amounts of Cd(Ⅱ) and Pb(Ⅱ) with a significantly large amount of La(Ⅲ) were simultaneously precipitated in a 1,000 mL sample solution with the ethanolic 8-hydroxyquinoline solution. The pH was adjusted to 9.0 with 2 M ammonia solution. The precipitates were floated with the aid of tiny nitrogen bubbles and supported by the stable foam layer of sodium lauryl sulfate. The floats were collected on the fritted glass filter by a suction. The material collected was dissolved with 5.0 mL of ethanol and 1.5 mL of concentrated nitric acid, and then diluted to 25.0 mL with a deionized water. The analytes were determined by a flame atomic absorption spectrophotometry. The recoveries of the analytes spiked in the sample were 94.8% for Pb(Ⅱ) and 92.0% for Cd(Ⅱ). This flotation technique is simple and rapid, and also applicable to the determination of trace Cd(Ⅱ) and Pb(Ⅱ) at lew ppb levels.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.813-822
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• 1996

In order to reduce carbon dioxide, one of the major greenhouse gases, a new type of copolymer, poly(alkylene carbonate) has been synthesized. The alternating copolymers have been obtained from carbon dioxide and various epoxides with zinc carboxylate as a catalyst. The number-average molecular weight of the polymer is about 50,000 and polydispersity is rather broad(5~10). The polymers are amorphous, and glass-clear materials that exhibit unusually facile and clean thermal decomposition behavior. Complete decomposition with no carbon residue is observed at elevated temperature even in an inert atmosphere. Terpolymers with bulkier epoxides improve the physical properties of the copolymer with simple epoxides. The decomposition properties of the polymer provide versatile applications such as ceramic, metal, and electronic binders and lost-foam casting. Further application of the polymer for the barrier film or the plasticizer will be investigated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.439-446
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• 2017

Portable low-cost Kinect sensor was used to analyze standing balance ability of the elderly. Eighty subjects who can walk alone and have a normal cognitive level participated in this experiment. Based on Berg Balance scale (BBS) test with 52 points, subjects were divided into Healthy older (HO: 46 persons, BBS: $53.80{\pm}1.19$) and Impaired older (IO: 34 persons, BBS: $49.06{\pm}2.03$) group. Each subject performed 30 seconds four different standing balance tests (EO: Eyes Open, EC: Eyes Close, EOf: Eyes Open on foam, ECf: Eyes Close on foam). Five variables (Mean distance, Range of distance, Root mean square, Mean velocity, 95% ellipse area) were calculated from the hip joint center movement of Kinect sensor. Results showed that there were significant differences between groups for four different standing tests. Calculated variables from kinect sensor showed significant correlation with BBS score. Especially, mediolateral mean distance, mediolateral root mean square, mediolateral range of distance and 95% ellipse area showed discriminative ability for all tests. Mean values of variables of IO were higher than those of HO, which means the decreased balance ability in IO compared with HO. Therefore, it was possible to estimate simple balance assessment of the elderly using portable low-cost Kinect sensor.

• Journal of Hydrogen and New Energy
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• v.35 no.2
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• pp.152-161
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• 2024

In this study, a fuel cell system for future defense unmanned vehicles was designed and validated. A Co/Al₂O₃-Ni foam catalyst for NaBH₄ hydrolysis was characterized using several analytical methods. A NaBH₄ hydrogen generation system with the Co/Al₂O₃-Ni foam catalyst continuously generated hydrogen at elevated reaction temperatures. The fuel cell system with the NaBH₄ hydrogen generation system was designed and tested. The performance of the fuel cell system was comparable to that of the fuel cell system using pure hydrogen. Therefore, the fuel cell system with the NaBH₄ hydrogen generation system is a suitable power source for future defense unmanned vehicles owing to its easy refueling and simple system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.349-356
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• 2020

The heat release rate (HRR) and fire growth rate of fire for the solid combustibles consisting of multi-materials was measured through the ISO 9705 room corner test, and the computational analysis in a closed compartment was performed to simulate a fire using the heat release rate prediction model provided by a Fire Dynamics Simulator (FDS). The method of predicting the heat release rate provided by the FDS was divided into a simple model and a pyrolysis model. Each model was applied and computational analysis was performed under the same conditions. As the solid combustible consisting of multi-materials, a cinema chair composed mostly of PU foam, PP, and steel was selected. The simple model was over-predicted compared to the predicted heat release rate and fire growth rate using the pyrolysis model in a closed compartment.