• Journal of the Korean Solar Energy Society
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• v.35 no.1
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• pp.89-96
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• 2015

n-octadecnae based shape stabilized phase change material (SSPCM) was prepared by using vacuum impregnation method. And an exfoliated graphite nanoplate (xGnP) which has high thermal conductivity properties is used as a PCM container. And then we made heat storage concretes which contains SSPCM for reducing heating and cooling load in buildings. In the prepararion process, the SSPCM was mixed to a concrete as 10, 20 and 30wt% of cement weight. The thermal properties and chemical properties of heat storage concrete were analyzed from Scanning electron microscope (SEM), Fourier transformation infrared spectrophotometer (FT-IR), Deferential scanning calorimeter (DSC), Thermogravimetric analysis (TGA) and TCi thermal conductivity analyzer. And we conducted surface temperature analysis of SSPCM and xGnP by using heat plate and insulation mold.

• The Journal of Korean Medicine
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• v.25 no.4
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• pp.220-225
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• 2004

Objective : Electroacupuncture is one of the primary remedies in oriental medicine. Elecroacupuncture was applied on a nocturia patient. Improvement of the symptoms was experienced. This case is reported in order to derive further studies evaluating the effectiveness of this treatment. Methods : Electroacupuncture on the Ciliao acupoint(BL32) was performed twice daily for 1 week. Results : After about 1 week of electroacupuncture on the Ciliao acupoint(BL32), there was a remarkable decrease of nocturia frequency. Conclusion: We present the case of a mao with an overactive bladder who had several stokes as well as hypertension. Electroacupuncture treatment performed on the Ciliao acupoint(BL32) remarkably improved nocturia.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.85-95
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• 2016

PBT (Plate Bearing Test) is a commonly used compaction estimation used to provide basal support for embankments. This study presents the results from experimental evaluations PBT, LWDT (Light Drop Weight Tester) test and Geogauge test with embankment materials which consist in sandy soil, crushed stone and rock. The results of this study indicate that the regression analyze results (r) from test results between Young's modulus and $k_{30}$, $E_v$ are 0.385 and 0.111~0.496, estimated very lack of correlation. The Geogauge is frequency vibration from machine to underground. Geogauge can not measure to accuracy test results when it is used on ground of the rock or crushed stone. The regression analyze results (r) from $E_v$ and Dynamic modulus are 0.502~0.847, different estimated by calculate method, as it were, when calculate $E_v$, least square method are appeared more accuracy than gradient of secant.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.130-130
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• 2017

비닐하우스의 골조를 구성하는 파이프는 부식을 방지할 목적으로 아연도강관을 사용한다. 그러나 시간이 지남에 따라 아연도금량 감소와 여러 외부 환경인자 등에 의하여 부식이나 침식이 진행되어, 외관상 녹이 생기고 강도와 연신율 등이 감소하게 된다. 이는 비닐하우스 전체의 내구성을 저하시키는 요인으로 작용하게 되는데, 이를 평가하기 위한 방법이나 기준은 미비한 실정이다. 이에 본 연구에서는 농업시설의 내구성을 평가하기 위한 방법의 하나로 각기 다른 경과년수를 갖는 비닐하우스로부터 채취한 서까래 파이프의 인장 시험을 실시하였다. 인장 시험에 사용된 서까래 파이프는 (구)시설원예시험장에 설치되어 있는 비닐하우스에서 경과년별로 채취하였으며, 지중매설부와 지상노출부로 구분하여 시편을 제작하였다. 인장 실험 결과 서까래 파이프의 경과년이 오래될수록 시편의 인장 강도는 작아지는 경향을 보이고 있으나, 파단연신율은 경과년과 연관성을 찾아보기 어려운 것으로 나타났다. 그리고 동일한 경과년을 갖는 서까래 파이프 시편에서 지중매설부의 인장 강도와 파단연신율이 지상노출부에 비해 대체로 작게 측정되었으며, 경과년이 증가할수록 인장 강도의 감소폭이 커지는 경향을 보이는 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1787-1790
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• 2005

We have developed satellite devices for fine attitude control of the Science & Technology Satellite-2 (STSAT-2) scheduled to be launched in 2007. The analog sun sensors which have been continuously developed since the 1990s are not adequate for satellites which require fine attitude control system. From the mission requirements of STSAT-2, a compact, fast and fine digital sensor was proposed. The test of the fine attitude determination for the pitch and roll axis, though the main mission of STSAT-2, will be performed by the newly developed FDSS. The FDSS use a CMOS image sensor and has an accuracy of less than 0.01degrees, an update rate of 20Hz and a weight of less than 800g. A pinhole-type aperture is substituted for the optical lens to minimize the weight while maintaining sensor accuracy by a rigorous centroid algorithm. The target process speed is obtained by utilizing the Field Programmable Gate Array (FPGA) in acquiring images from the CMOS sensor, and storing and processing the data. This paper also describes the analysis of the optical performance for the proper aperture selection and the most effective centroid algorithm.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.4
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• pp.15-20
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• 2016

Even though the control device of the heating system works well, insufficient water flow rates can degrade control performance and thermal comfort. The water flow rate should be adjusted appropriately to cope with the heating load of each zone. In order to solve these problems, a new balancing concept 'dynamic balancing' was proposed where a balancing valve opening can be automatically modulated according to the heating condition of the room. This study analyzed the effects of dynamic balancing upon indoor thermal environment and energy consumption in a radiant floor heating system through field measurement. Under part-load conditions, the use of a dynamic balancing is a more effective method to reduce energy consumption and to prevent a cavitation. Dynamic balancing is able to help boost the temperature of a room in the start-up period.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.9-15
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• 2013

A new process for the synthesis of polyphenylcarbosilane (PPCS) via thermal rearrangement of polymethylphenylsilane (PMPS) in supercritical cyclohexane was proposed and investigated at reaction temperatures of $380-420^{\circ}C$, reaction times of 1-2 h, and a pressure of 15 MPa. The structure, molecular weight, and molecular weight distribution of the product were characterized by FT-IR, Si-NMR, and GPC. The ceramic yield was also measured by TGA analysis. High-quality PPCS with high molecular weight and ceramic yield can be synthesized via a supercritical process. Furthermore, this process, when compared to the conventional method, tends to moderate the reaction conditions such as reaction temperature and time. It is concluded that thermal rearrangement in supercritical fluid is an efficient and viable process in terms of the resulting yield, efficiency, and reaction time compared with those of the conventional PCS production process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.538-541
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• 2002

탄소나노튜브 (CNT)가 도포된 평면형 에미터와 원형 개구의 게이트 전극을 가지는 삼전극 전계방출 소자의 전계방출 특성을 시뮬레이션하였다. 체계적인 시뮬레이션을 위해 소자 내 전위의 공간적 분포 특정을 결정하는 전계형상인자 $\gamma$를 정의하고 이 값에 따른 전위분포의 특성과 방출 전자의 궤적을 계산하였다. 계산 결과$\gamma$ > 1 인 전압조건에서는 에미터의 가운데를 중심으로 강한 전자방출이 발생하고 전자빔이 구조의 축 방향으로 자체 집속됨을 알 수 있었다. 이렇게 되면 에미터와 게이트의 정렬이 전혀 필요하지 않게 되며 또한 별도의 전자집속회로 없이도 에미터와 양극에 있는 형광체가 1:1 로 대응하는 획기적인 디스플레이 구조를 가능하게 해 준다 적정 전압조건에서 CNT의 전계강화인자 $\beta$의 변화에 따른 총 전류를 계산한 결과，$\beta$ >3000인 CNT를 사용할 경우 실제 소자로서 구현이 가능함을 확인하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.510-513
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• 2002

띠모양의 에미터와 에미터와 정렬된 띠모양의 케이트 구멍을 가진 탄소나노튜브(CNT) 삼극 구조에 대하여 전계방출 시뮬레이션을 수행하였다. 전자방출은 주로 가장자리에서 발생하였으며 에미터와 게이트사이의 간격이 가까워지면 급격히 증가하였다. 전자방출 특성도 상당히 우수하였다. 한쪽 가장자리만을 사용한 삼극구조의 경우에는 방출된 전자의 궤적이 좁은 띠모양으로 형성되어 방향성이 매우 우수하게 나타났다. 띠모양의 에미터 및 게이트로 이어진 삼극구조는 제작이 용이하고 조립할 때 정렬이 쉬운 장점이 있다.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.129-134
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• 2005

The behavior of whole system is affected by a minor change of system in the hydronic radiant floor heating system. Under partial load condition, the change of system resistance causes overflow of supply water. This unexpected effect is the cause of several problems in the heating system. In this study, we find some factors were validated with several computer simulations. After validation of this result, several conceptual solutions are evaluated to prevent overflow.