• 한국태양에너지학회 논문집
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• 제29권4호
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• pp.15-21
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• 2009

Since the solar radiation is main input for sizing any solar photovoltaic system and solar thermal power system, it will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 and direct normal insolation data since December 1992 at 16 different locations. Because of a poor reliability of existing data, KIER's new data will be extensively used by solar energy system users as well as by research institutes. Among some significant results, the yearly averaged horizontal global insolation was turned out 3.60 kWh/$m^2$/day and the yearly mean 2.62 kWh/$m^2$/day of the direct normal insolation was evaluated for all days.

• 한국포장학회지
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• 제15권1호
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• pp.25-32
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• 2009

It is now widely recognized that the disposal of packaging waste is an increasing environmental concern. Recent interest in polymer waste management of packaging materials has added incentive to the research. Poly(vinyl alcohol) is a readily biodegradable water-soluble polymer. However, this polymer cannot be processed by conventional extrusion technologies because the melting point of PVA is close to its decomposition temperature. Therefore, PVA films have been mostly prepared by solvent casting from water. Applications of PVA include sizing, binders, fibers, and films for agricultural chemicals and hospital laundry bags. A better understanding of PVA films, which also play important roles in the degradation of plastics, will expand the usage of PVA. Composite films based on PVA generally exhibit better mechanical and thermal properties than pure PVA. The aim of this review article is to review types, formation, and properties of PVA films and PVA based composite films used in packaging related researches.

• 한국태양에너지학회 논문집
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• 제30권2호
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• pp.81-86
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• 2010

Since the solar energy resource is the main input for sizing any solar photovoltaic system and solar thermal power system, it is essential to utilize the solar radiation data as a application and development of solar energy system increase. It will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 and direct normal insolation data since December 1992 at 16 different locations in Korea. Because of a poor reliability of existing data, KIER's new data will be extensively used by solar energy system users as well as by research institutes. From the results, the yearly averaged horizontal global insolation was turned out 3.60kWh/$m^2$/day and a significant difference of horizontal global insolation is observed between 1982~1990 and 1991~1999, 2000~2008 through 16 different cities in Korea.

• 한국유체기계학회 논문집
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• 제17권6호
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• pp.77-83
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• 2014

The vessel of integral reactor contains its major primary components such as the fuel and core, pumps, steam generators, and a pressurizer, so its size is proportional to the required space for the installation of each component. The steam generators take up the largest volume of internal space of reactor vessel and their volumes is substantial for the overall size of reactor vessel. Reduction of installation space for steam generators can lead to much smaller reactor vessel with resultant decrease of overall cost for the components and related facilities. A printed circuit heat exchanger is one of the compact types of heat exchangers available as an alternative to conventional shell and tube heat exchangers. Its name is derived from the procedure used to manufacture the flat metal plates that form the core of the heat exchanger, which is done by chemical milling. These plates are then stacked and diffusion bonded, converting the plates into a solid metal block containing precisely engineered fluid flow passages. The overall heat transfer area and pressure drops are evaluated for the steam generator based on the concept of the printed circuit heat exchanger in this study. As the printed circuit heat exchanger is known to have much larger heat transfer area density per unit volume, we can expect significantly reduced steam generator compared to former shell and tube type of steam generator. For the introduction of new steam generator, two design requirements are considered: flow area ratio between primary and secondary flow paths, and secondary side parallel channel flow oscillation. The results show that the overall volume of the steam generator can be significantly reduced with printed circuit type of steam generator.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.63.1-63.1
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• 2010

Since the solar energy resource is the main input for sizing any solar photovoltaic system and solar thermal power system, it is essential to utilize the solar radiation data as a application and development of solar energy system increase. It will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at 16 different locations in Korea and for the more detailed analysis, Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. From the results, the measured data has been collected at 16 different stations and estimated using satellite at 23 different stations over the South Korea from 1982 to 2009. The Result of analysis shows that the annual-average daily global radiation on the horizontal surface is $3.56kWh/m^2/day$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1140-1145
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• 2004

Laser-induced incandescence (LII) is introduced as a valuable tool for the characterization of nanoparticles in flame environments. This technique is based on the heating of the particles by a short laser pulse and the subsequent detection of the thermal radiation. It has been applied successfully for the investigation of soot in different fields of application. The evaluation of the temporal decay of the laser-induced incandescence (LII) signal from soot particles is introduced as a technique to obtain two-dimensional distributions of particle sizes and is applied to a laminar diffusion flame. This novel approach to soot sizing exhibits several theoretical and technical advantages compared with the established combination of elastic scattering and LII, especially as it yields absolute sizes of primary particles without requiring calibration. With this technique a spatially resolved 2-D measurement of soot primary particle sizes is feasible in a combination process form the ratio of emission signals obtained at two delay times after a laser pulse, as the cooling behavior is characteristic of particle size.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1152-1157
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• 2004

Temporal behavior of the laser induced incandescence (LII) signal is often used for soot particle sizing, which is possible because the cooling behavior of a laser heated particle is dependent on the particle size. In present study, LII signals of soot particles are modeled using two non-linear coupled differential equations deduced from the energy- and mass-balance of the process. The objective of this study is to see the effects of particle size, laser fluence on soot temperature characteristics and cooling behavior. Together with this, we focus on validating our simulation code by comparing with other previous results. Results of normalized LII signals obtained from various laser fluence conditions showed a good agreement with that of Dalzell and Sarofim's. It could be found that small particles cool faster at a constant laser fluence. And it also could be observed that vaporization is dominant process of heat loss during first 100ns after laser pulse, then heat conduction played most important role while thermal radiation had little influence all the time.

• Journal of Astronomy and Space Sciences
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• 제24권2호
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• pp.179-194
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• 2007

인공위성 전력계의 설계 및 분석은 위성 전체의 무게, 크기 및 성능을 결정하는 중요 변수로 작용한다. 위성체의 모든 타 부분체들은 전력계 설계의 영향을 받으며 특히 발사체 선정, 열 제어계 설계 및 구조계 설계의 경우 전력계의 성능 및 제한 조건 등 전력계 설계 결과에 매우 큰 영향을 받는다. 이 논문에서는 현재 국내에서 지속적으로 개발되고 있는 저궤도 위성의 전력계 설계를 위한 새로운 프로그램을 소개하고 타 위성의 설계 자료를 이용한 개발된 프로그램의 성능 실험 결과를 기술하였다. 실험 결과 제안된 전력계 설계 프로그램은 전력계 사이징 뿐 아니라 궤도상에서의 전력계 성능을 예측하는데도 사용할 수 있음을 보였다.

• 설비공학논문집
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• 제24권10호
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• pp.718-723
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• 2012

The purpose of this study is to propose modeling method of Underfloor Air Distribution System with reliability and validity by comparing characteristics of modeling methods. For this, the modeling methods of UFAD were selected by investigating various modeling methods of previous researches. Then, simulations were conducted by using EnergyPlus which is dynamic analysis program of building energy. Annual energy consumption for each method was compared with a wide range of indoor thermal loads. As a result, the methodology of reducing internal gains can cause under sizing of the system. It suggests modeling methods to reflect occupied zone air-conditioning, temperature stratification and supply plenum which are the main characteristics of UFAD.

• 한국기계가공학회지
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• 제11권3호
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• pp.55-61
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• 2012

The structure of winch brake disk was successfully designed and developed based on sizing optimization. In this research, static analysis was performed by commercial software ANSYS v12.0. To simulate the working process of disk brake, the real properties of materials and working conditions were considered. Based on the results of the static structural analysis, the existing designs of the brake discs were optimized. Among existing designs, there are three cases that have achieved an efficient light weight around 200g. As a result, the optimized weight of each case was 3.41kg, 3.42kg, and 3.44kg, respectively. Finally, through prototyping and performance testing, the stability of the optimized brake disc was verified. Although, this free-fall winch brake disk had been developed in design and evaluation techniques, more detailed plans for developing the disk brake structure were also proposed as a further study based on this research.