• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.130-131
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• 2019

As part of recent low-energy policies, thermal insulation standards for buildings are being tightened every year. In addition, the conventional styrofoam insulating material has a problem that the thickness of the heat insulating material to achieve a standard heat permeability is rapidly increased. Due to the thick insulation, there is a high risk of spreading vulnerable structures such as fire due to lack of space between buildings. On the other hand, the method of using the insulation as a formwork is known to be excellent cost saving effect through the reduction of the formwork usage and the simplification of the external insulation work. In order to solve this problem, this study aims to fabricate a multi-layered insulator that combines high-performance phenolic foam insulation and styrofoam insulation and evaluate the deflection characteristics for use as formwork.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.45-46
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• 2023

CLC is used as a filling material for many buildings, and according to energy saving design standards, CLC also requires insulation performance. However, it shows lower insulation performance compared to organic insulation, so additional research is needed. Therefore, in this study, the insulation properties of CLC were analyzed by incorporating EPS beads with high insulation performance into CLC. In this experiment, EPS beads and blast furnace slag were replaced, and W/B was fixed at 33%. The EPS Bead mixing ratio was divided into 5 levels: 0, 0.5, 1.0, 1.5, 2.0 (%), and the experimental items were measured for apparent density and thermal conductivity. As a result of the experiment, the apparent density and thermal conductivity tended to decrease as the mixing ratio of EPS beads increased. It is judged that the density decreased due to the low density and the micropores inside, and the thermal conductivity also decreased.

• 유통과학연구
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• 제16권11호
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• pp.21-27
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• 2018

Purpose - This study investigates the financial ratio of savings banks and the effect of the ratio having influence upon bankruptcy by quantitative empirical analysis of forecast model to give material of better management and objective evidence of management strategy and way of advancement and risk control. Research design, data, and methodology - The author added two growth indexes, three fluidity indexes, five profitability indexes, and four activity indexes CAMEL rating to not only the balance sheets but also the income statement of thirty savings banks that suspended business from 2011 to 2015 and collected fourteen financial ratio indexes. IBMSPSS VER. 21.0 was used. Results - Variables having influence upon bankruptcy forecast models included total asset increase ratio and operating income increase ratio of growth index and sales to account receivable ratio, and tangible equity ratio and liquidity ratio of liquidity ratio. The study selected total asset operating ratio, and earning and expenditure ratio from profitability index, and receivable turnover ratio of activity index. Conclusions - Financial supervising system should be improved and financial consumers should be protected to develop saving bank and to control risk, and information on financial companies should be strengthened.

• 한국농촌건축학회논문집
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• 제20권4호
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• pp.77-84
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• 2018

The purpose of this study is to certify the eco-friendly elements of traditional Hanok based on the G-SEED 2016 Criteria. For this study, estimating the eco-friendly elements of the two traditional Hanok - Myeong Jae's old house and General Lee Sam's old house - based on the G-SEED 2016 Criteria. The results were as follows: Each of the two traditional Hanok can get the sufficient points for grading at G-SEED 2016, but the two required criteria are not be able to get the points; energy performance such as heat storage of traditional mud wall and water saving equipments. On the other hand using eco-friendly materials in traditional Hanok are satisfied with the Material category. Also using rainwater and underwater through garden and pond in traditional Hanok are satisfied with the Ecological environment category. But lots of the other eco-friendly elements of traditional Hanok can not be estimated by G-SEED 2016 Criteria. Modern Hanok will be able to obtain G-SEED 2016 certification when using the valid eco-friendly elements of traditional Hanok and applies new technologies such as water saving equipments.

• 한국가구학회지
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• 제27권4호
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• pp.318-324
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• 2016

Recently, pedestrians suffered inconveniences with moving on the next building due to the high-rise buildings. So, the number of passageways is increasing for convenience of pedestrians. Currently, people are paying attention to building energy saving. We anticipated that It increases the cooling load of the building and building energy by a passageway. We chose a passageway for a subject because people are paying attention to building energy saving lately. The purpose of this study was to analyze the indoor thermal environment according to the passageway. We measured temperature of building with passageway using a multifunctional device in order to progress the study. On analysis based on investigation, finishing material and glass area of passageway have an effect on indoor thermal environment. The result shows that the cooling load of building alter depending on characteristic of passageway.

• 한국기계가공학회지
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• 제11권4호
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• pp.97-103
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• 2012

This study investigates thermal insulation properties of multi layer materials depending on thickness of air layers. Numerical analysis on the heat flow of different insulating materials was conducted to identify whether their temperature distributions demonstrate the reduced rate of heat transfer conclusively or not. Analytical model is divided into two categories. One is to distinguish temperature distribution of the air-layer materials from the non-air layer ones. The other is to compare the efficacy between eight-layered insulating materials with no air-layer contained and three-layered insulating materials which include an air-layer definitely. In the latter case, the identical thickness is assigned to each material. The effect of thermal insulation by including an air-layer is verified in the first analytical model. The result of the second model shows that the insulation of the eight-layered materials is coterminous at the three-layered ones with an air-layer and the thermal insulation of the two materials is imperceptible. The benefits of cost and energy saving are anticipated if air-layers are efficiently incorporated in multi layer insulating materials in a greenhouse.

• 조명전기설비학회논문지
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• 제12권2호
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• pp.121-128
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• 1998

새로운 형태의 자기식 형광등 안정기를 설계 개발하여 고효율화 성능시험을 수행하였다. 새로운 철심재료인 고성능의 G-9 재료를 사용하고, 철심구조와 모양을 개선하였고 코일의 동선을 짧고 굵은 것으로 대체하여 직류저항 성분을 줄여서 안정기 자체의 에너지 손실을 감소시켰다. 반도체형 점등회로를 대폭 개선하여 순간 점등을 가능하게 하고 형광램프의 사용수명연장, 화재방지 등을 할 수 있게 하였다. 안정기 자체의 에너지 감소가 1.7Watt, 형광등 조명광 향상이 7.6[%] 증가 등 큰 에너지 절약을 보였다. 본 연구결과는 형광등 안정기의 기술 향상과 국가 전력소비 절감효과 등 중요한 의미가 있다.

• 한국표면공학회지
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• 제27권4호
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• pp.207-214
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• 1994

In consideration of global environmental protection and fuel saving, aluminum alloy sheets for auto body panels such as hood, fender etc., are expected one of the most promising materials for weight saving of cars. The chemical conversion coating is required to prevent the filiform corrosion occurring on painted aluminum. However the conventional process for the composited material mixed with aluminum and steel is complexs; aluminum part is chromated and assembled to the body, and then the steel body undergoes Zn phosphating. In order to overcome the low productivity due to the complex process and the environmental problem with a conventional process, a simultaneous zinc phosphating process for alsuminum and steel in an assembled condition is demanded. Newly developed phosphate solution has been investigated to characterize the phosphating behavior under various conditions. The optimum conditions of the phosphating solution for the application of the paint treatment derived as follows : about 0.3 for the ratio of Zn to $PO_4$, , 200~500 ppm for the concentration of fluoride ion, and 2.5~4.0 for pH. The concentration of dissolved aluminum ion must be kept below 2--ppm and suitable accelerator is found to be a mixture of 1g/$\ell$ $NO_2\;^-$, and 6g/$\ell$ $NO_3\;^-$.

• 동력기계공학회지
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• 제14권4호
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• pp.63-67
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• 2010

This paper introduces the eddy current signal characteristic of magnetic and non-magnetic gas turbine rotor. In the past, Magnetic particle inspection method was used in magnetic material for qualitative defect evaluation and the ultrasonic test method was used for quantitative evaluation. Nowadays, eddy current method is used in magnetic gas turbine rotor inspection due to advanced sensor design technology. We are studying on the magnetic gas turbine rotor by using eddy current method. We prepared diverse depth specimens made by magnetic and non-magnetic materials. We select optimum frequency according to material standard penetration data and experiment results. We got the signal on magnetic and non-magnetic material about 0.2 mm, 05 mm, 1.0 mm, 1.5 mm 2.0 mm and 2.5 mm depth defects and compare the signal amplitude and signal trend according to defect depth and frequency. The results show that signal amplitudes of magnetic are bigger than non-magnetic material and the trends are similar on every defect depth and frequency. The detection and resolution capabilities of eddy current are more effective in magnetic material than in non-magnetic materials. So, the eddy current method is effective inspection method on magnetic gas turbine rotor. And it has the merits of time saving and simple procedure by elimination of the ultrasonic inspection in traditional inspection method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.401-401
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• 2009

Recently, demands for the development of compact, lightweight power supplies with higher power density and higher efficiency have been increased. Since Piezoelectric Transformer (PT) was emerged in device and material industry, it has been suggested as a viable alternative to the magnetic transformer in some applications. PT has some advantages such as low profile and mechanical energy transfer with little electromagnetic interface (EMI). Also, PT can provide high voltage stepping ratio with good isolation and requires no copper windings saving copper usage especially for large voltage conversion differences. Conventional control of PT converter has mainly two-way. One is the pulse frequency modulation (PFM) control method and the other is the pulse width modulation (PWM) control with frequency fixed method. It is known that the maximum PT efficiency can be obtained when it operates near the resonant frequency of the PT. And, also PT's resonant frequency moves according to the load condition. Therefore, selection of PT converter control method is very difficult. This paper analyzes general piezo-electric converter modeling and proposes a guide-line to selection of control method and stabilization control.