• Journal of Powder Materials
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• v.23 no.2
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• pp.112-119
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• 2016

A powder injection molding process is developed and optimized for piezoelectric PAN-PZT ceramics. Torque rheometer experiments are conducted to determine the optimal solids loading, and the rheological property of the feedstock is evaluated using a capillary rheometer. Appropriate debinding conditions are chosen using a thermal gravity analyzer, and the debound specimens are sintered using sintering conditions determined in a preliminary investigation. Piezoelectric performance measures, including the piezoelectric charge constant and dielectric constant, are measured to verify the developed process. The average values of the measured piezoelectric charge constant and dielectric constant are 455 pC/N and 1904, respectively. Powder injection molded piezoelectric ceramics produced by the optimized process show adequate piezoelectric performance compared to press-sintered piezoelectric ceramics.

• Economic and Environmental Geology
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• v.21 no.2
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• pp.175-184
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• 1988

Ten under 2 micron size fractions of the montmorillonite from Yongdongri area, Gyeongsangbug-Do were studied using X-ray powder diffraction, cation exchange measurement, differential thermal analysis, thermogravimetric analysis, differential thermal scanning calorimetry and chemical analysis. Montmorillonites occurring at same deposit show limited variation in chemical composition whereas in thermal properties they do not. Their dehydroxylation endothermic peaks are "abnormal" type with a small range of variation of peak temperature reflecting tetrahedral substitution of Al for Si. Data from DSC show that divalent-cation saturated montmorillonite has relatively a higher endothermic heat capacity than monovalent-cation saturated montmorillonite, indicating that cations with higher electronegativity hold more water molecules.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.1
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• pp.17-25
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• 2014

Periodically, harmful algal blooms (HABs) have occurred, with impacts on various areas including public health, tourism, and aquatic ecosystems, especially aquacultured and caged fisheries. To prevent or manage invasions of HABs into fish farms on an emergency basis, many methods have been proposed. Frequently over the past 30 years in coastal countries, treatments of clay and clay mixed with polyaluminum chloride (PAC) and chitosan have been tested for HAB-removal effectiveness in both the laboratory and the field. In Korea, yellow loess clay (hwangto) has been dispersed using electrolytic clay dispensers, both to decrease the amount of yellow loess clay's usage in containers and enhance HAB-removal efficiency. However, this emergency method has limitations, among which is the requirement for more effective controlling agents for field applications. Thus, in this paper, we review technologies for clay-based red tides prevention and control and their limitations, and, further, introduce next-generation algicidal technologies for the emergency protection of fish farms.

• Journal of the Korean Solar Energy Society
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• v.29 no.2
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• pp.70-75
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• 2009

In this experiment, we did sampling 6 kinds of photovoltaic modules and analyzed the discrepancy of measurement results between l laboratory and 4 PV makers to have performance repeatability at Standard Test Condition(STC) condition. From the KIER's results, Korea's standard test laboratory, other laboratory showed -10% measurement variation. The causes came from correction of reference cell, test condition and the state of skill. Form the comparison test, we analyzed the problems. But three PV maker reduced measurement variation, other one PV maker and one test laboratory didn't improve the problems of correction of reference cell, test condition and the state of skill. Also, High Efficiency Module had a big discrepancy of -10.0$\sim$-6.2% among 3 laboratories which have a less than 10msec light pulse duration time. This made low spectrum response speed so the Fill Factor decreased maximum output power under 10msec light pulse duration time

• Solar Energy
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• v.20 no.2
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• pp.31-42
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• 2000

Since the direct normal insolation is a main factor for designing any focusing solar system, it is necessary to evaluate its characteristics all over the country. We have begun collecting direct normal insolation data since December 1990 at 16 different locations and considerable effort has been made for constructing a standard value from measured data at each station. KIER(Korea Institute of Energy Research)'s new data will be extensively used by concentrating system users or designers as well as by research institutes. From the results, we can conclude that 1) Yearly mean $4,576kcal/m^2.day$ of the direct normal insolation was evaluated for clear day all over 16 areas in Korea. 2) Clear day's direct normal insolation of spring and summer were $4,710kcal/m^2.day$ and $4,960kcal/m^2.day$, and for fall and winter their values were $4,484kcal/m^2.day$ and $4,151kcal/m^2.day$ respectively. So, spring and summer were higher, and fall and winter were lower than the yearly mean value.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.133-137
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• 2011

Low-e glazing is classified as soft low-e glazing and hard low-e glazing. Hard low-e glazing can be temperable and its handling is comfortable because its coating film is a oxide film generated at high temperatures. But there is a fatal weakness that its insulation performance and shielding performance are lower compared to soft low-e glazing by low electrical conductivity of coating film. Soft low-e glazing is excellent because its coating film consists of Ag that is excellent electrical conductivity and it has strength that can supply various product consumers want. But soft low-e glazing has weaknesses that temperable and handling are difficult because Ag is oxidized easily. Therefore this study analyzes thermal performance of glazing by changing filling gas according to applying low-e glazing through simulation to judge performance before making sample. After this process, a comparative experimental study was done through TVS by making temperable low-e glazing.

• Journal of the Korean Solar Energy Society
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• v.32 no.4
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• pp.65-70
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• 2012

Each country has implemented various environmental policies to prevent natural disasters and destruction of ecosystem caused by global wanning. The republic of Korea also was performed building energy efficiency rating certification system as part of paradigm of 'Low carbon green growth' since 2010. However, the status on the building energy efficiency rating certification system has not been analyzed. In this study, We analyzed the elements affecting the energy efficiency of small office buildings focusing the status and certification cases of the building energy efficiency rating system. As a result, it is judged that thermal performance contribution of the building envelope is not high in the buildings certificated the first grade of the building energy efficiency rating system.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.59-62
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• 2011

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 I 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 2000. The Result of analysis shows that the armual-average daily global radiation on the horizontal surface is $3.56kWh/m^2/day$ and Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.27 to +3.65% from the measured values.

• Journal of the Korean Solar Energy Society
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• v.28 no.1
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• pp.51-56
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• 2008

Since the direct normal insolation is a main factor for designing any solar thermal power system, it is necessary to evaluate its characteristics all over the country. We have begun collecting direct normal insolation data since December 1992 at 16 different locations and considerable effort has been made for constructing a standard value from measured data at each station. KIER(Korea Institute of Energy Research)'s new data will be extensively used by solar thermal concentrating system users or designers as well as by research institutes. From the results, we can conclude that 1) Yearly mean $2.67\;kWh/m^2/day$ of the direct normal insolation was evaluated for all days all over the 16 areas in Korea. 2) All day's direct normal insolation of spring and summer were $2.91\;kWh/m^2/day$ and $2.23\;kWHm^2/day$, and for fall and winter their values were $2.78\;kWh/m^2/day$ and $2.77\;kWh/m^2/day$ respectively. So, spring, fall and winter were higher, and summer was lower than the yearly mean value.

• Solar Energy
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• v.20 no.4
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• pp.17-24
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• 2000

Thermal performance of a SAAHPS (Solar and Ambient-air-assisted Heat Pump System) located in KIER is simulated with TRNSYS 14.2. The SAAHPS is composed of dual evaorators, each of which is used as a solar fluid heat source and an air fluid heat source. Polynomial coefficients data for the SAAHPS is supplied with Frigosoft, a program widely used for heat pump modeling. In general, collector area and storage volume are 2 key parameters in SAAHPS thermal performance. A parametric study is performed in this study to assess sensitivity of collector area and storage volume in SAAHPS. We concluded that firstly collector area and storage volume are the primary variables in SAAHPS thermal performance, secondly COP of SAAHPS is higher than that of conventional heat pumps. Therefore. collector efficiency can be enhanced swith SAAHPS during a heating season.