• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.499-502
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• 2004

The temperature distribution of a glass plate heated in the infrared heating chamber has been investigated. Temperature of the glass panel is measured using a set of thermocouples and the optical pyrometer. Temperatures measured by thermocouples have good agreement with those by the pyrometer. The temperature uniformity of the panel is improved with wall reflectivity, which is one of the important factors to uniformly heat the panel

• Korean Journal of Materials Research
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• v.13 no.10
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• pp.697-702
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• 2003

FT-IR and thermograph were used to investigate the infrared radiation characteristics of $SiO_2$film made by the sol-gel method. FT-IR spectrum of the $SiO_2$film showed high infrared absorption by Si-O-Si vibration at 1220, 1080, 800 and cm$460^{-1}$ The infrared absorption and radiation wavelength ranges of the $SiO_2$film measured by the integration method coincided with the reflection method, and the infrared emissivity was 0.65, equally. Depending on the bonding of elements, the infrared emissivity was high in the wavelength range where the infrared absorption rate was high, that follows the Kirchhoff's law. The emissivity showed the highest value in the wavelength range between $8∼10\mu\textrm{m}$. $SiO_2$film was considered as an efficient materials for infrared radiator at temperature below 10$0^{\circ}C$. The heat radiation temperature was $117^{\circ}C$ for the aluminum plate, but $146^{\circ}C$ for the $SiO_2$film after 7 minutes heat absorption, consiquently, $29^{\circ}C$ higher than the former.

• Atmosphere
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• v.21 no.3
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• pp.285-300
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• 2011

To discriminate and eliminate chaff echoes in radar measurements, a new removal algorithm in two-dimensional reflectivity composite at the height of 1.5 km has been developed by using the brightness temperature($T_B$) obtained from MTSAT-1R. This algorithm utilizes the fact that chaffs are not appeared in infrared satellite data of MTSAT-1R, but detected in radar measurements due to their significant backscattering in the given radar wavelength. The algorithm is evaluated for three different situations: chaff only, chaff mixed with convective storms, and chaff covered with clouds. The algorithm shows excellent performance for the cases of chaff only and chaff mixed with convective storms. However, the performance of the algorithm significantly depends on the presence of clouds. Thus, the statistical analysis of $T_B$ is performed in order to optimize the monthly threshold.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4139-4145
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• 2012

This paper shows an antireflection coating design skill for utilization the thin-film silicon solar cell in the future. The reflectivity of each index profile previously suggested as linear, cubic and quintic function has been calculated and compared. Each index profile is applied to the antireflection coating consisting of 6 layers with 180nm thickness. Also we suggest the graded index profile and compare it's reflectivity to the linear, cubic and quintic's ones. As a results we find the reflectivity generally decreases as the order goes to higher. However the reflectivity in the graded index profile shows the higher(lower) value than ones in the linear, cubic and quintic especially in the shorter(longer) wavelength range from 500 nm to below 700 nm(above 700 nm to 800 nm). Therefore we find that the graded index profile structure could be applied for the better antireflection coating design scheme especially for optical device and optical filter in the range of from deep red to infrared.

• Journal of the Korean Ceramic Society
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• v.37 no.3
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• pp.256-262
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• 2000

The dielectric properties of complex perovskite ($Pb_{1-x}Ca_{x}$)($Fe_{0.5}Ta_{0.5}$)$O_{3}$ with >($0.5{\le}x{\ge}0.65$ were investigated at microwave frequencies. Dilectric constant decreased with increasing Ca content, and was directly proportional to the cube of average ionic ra야 of A-site. For the specimen of x=0.6 sintered at $1250^{\circ}C$ for 3 h in air, dielectric constant (k) of 63, QF of 11000 GHz, and the temperature coefficient of resonant frequency(TCF) of -14ppm/$^{\circ}C$ were obtained. As Ca content increased, TCF of the specimen negatively increased due to the reduction of the tolerance factor(t). Changes in intrinsic loss with varying Ca content was investigated by the infrared reflectivity spectra ranging 50 to 4000 $cm^{-1}$, which were calculated by the Kramers-Kronig analysis and classical oscillator model. The relative tendency of microwave dielectric properties of the ($Pb_{1-x}Ca_{x}$)($Fe_{0.5}Ta_{0.5}$)$O_{3}$ specimens calculated from the reflectivity data were in good agreement with the results by the post resonant method.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.406-412
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• 2003

FT-IR and thermography were used to investigate the infrared radiation characteristic of SiO$_2$ film and SiO$_2$/Fe$_2$O$_3$film coated on aluminum. Through FT-TR spectrum, SiO$_2$film showed high infrared absorption in accordance with the stretching vibration of Si-O-Si, and as$ Fe_2$$O_3$was mixed additional absorption band appeared resulting from the stretching vibration of Fe-O at $590cm^{-1}$ and the bond of Si-O-Fe at $900 cm^{-1}$ The two kinds of film measured by the integration method and the reflective method coincided with each other in the wavelength area of infrared absorption and radiation, and corresponded well with Kirchhoff's law as the infrared emissivity is high in wavelength where infrared absorption rate is high. The emissivity of $SiO_2$ film was 0.65 and that of $SiO_2$/Fe$_2$$O_3$film was 0.77, so the addition of$ Fe_2$$O_3$ raised the infrared emissivity by approximately 13%.$ SiO_2$$Fe_2$$O_3$ film is efficient as an infrared radiator at below $100^{\circ}C$. The temperature of heat radiation after 7 minutes was 117$^{\circ}C$ in aluminum plate and $155^{\circ}C$ in $SiO_2$$Fe_2$$O_3$ film, $38^{\circ}C$ higher than the former.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.565-570
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• 2017

The various techniques proposed previously to obtain a good antireflection(AR) coating induce a scattering of incident light by nanoparticles or control the refractive index by using different materials. This paper compares a suggested graded index profile with the quintic index profile previously suggested for producing an index profile that gives good performance from an AR coating. We assume the structure of the AR coating has three, six, and nine layers with 180 nm total thickness. The wavelength of incident light ranges from 300 nm to 1100 nm. We use the transfer matrix theory for a single layer to obtain the reflectivity of three, six, and nine layers. The reflectivity of two different index profiles with three, six, and nine layers is compared. As a result, the suggested graded index profile shows lower reflectivity than the quintic index profile with three layers, especially in the wavelength range from about 600 nm to 1100 nm. Therefore, we expect that these results can be applied to optical devices and filters in the range from visible(red) to near infrared.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.3
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• pp.12-19
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• 2000

Knowledge for reflectance characteristic of interesting targets will provide us with actual application of remote sensing on agriculture. In this study, we have measured and analyzed reflectivity characteristics based on growing status from transplanting time to harvesting time. Rice paddies transplant into 3 fields at 20, May, 1999. Measurement of reflectivity characteristics were carried out with a portable spectroradiometer for frequencies from 300nm to 1100nm during the time period from 11:00 AM to 01:00 PM of clear sky and calm a day. The measurements for a day repeated 3 times(also, 3 times to each measurement)for reliable values. In result, we found that averaged reflectivity of visible range has about 2.34% - 2.55% in blue region(400nm-498nm), about 5.05% - 6.01% in green region(500nm-598nm) and about 4.21% - 5.24% in red region(600nm-698nm). It must be noted that the more rice canopy grows, the more spectral reflectivity decreases in visible region. Also, we separated infrared region into two cases - One case is increasing region with 700nm-780nm, the other is fixed region with 800nm-1100nm. Averaged reflectivity of these regions has about 22.3% - 23.0% in increasing region, about 29.4% - 33.1% in fixed region. It must be noted that more rice canopy grows, the more spectral reflectivity also increases up to 23, Aug. in infrared region. After 23, Aug, the reflectivity has a tendency toward decrease.

• Applied Science and Convergence Technology
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• v.24 no.2
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• pp.41-46
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• 2015

Transparent conductive oxides (TCOs) are essential material in optoelectronics such as solar cells, touch screens and light emitting diodes. Particularly TCOs are attractive material for infrared cut off film due to their high transparency in the visible wavelength range and high infrared reflectivity. Among the TCO, Indium tin oxide has been widely used because of the high electrical conductivity and transparency in the visible wavelength region. But ITO has several limitations; expensive and low environmental stability. On the other hands, fluorine doped tin oxide (FTO) is well known for low cost, weather ability and stable in acidic and hydrogen. In this study, two different magnetron sputtering techniques with RF and DC modes at room temperature deposition of FTO thin film was conducted. The change of oxygen content is influence on the topography, transmittance and refractive index.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.295-298
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• 2013

Nano-size manganese ferrite reinforced conductive polypyrrole composites reveal a core-shell structure by in situ polymerization, in the presence of dodecyl benzene sulfonic acid as the surfactant and dopant, and iron chloride as the oxidant. The structure and magnetic properties of manganese ferrite nano-fillers were measured, by using X-ray diffraction and vibrating sample magnetometer. The morphology, microstructure, and conductivity of the composite were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and four-wire technique. The microwave-absorbing properties of composites reinforcement dispersed in resin coating with the coating thickness of 1.2 nm were investigated, by using vector network analyzers, in the frequency range of 8~12 GHz. A reflection loss of -8 dB was observed at 10.5 GHz.