• The Korean Journal of Ceramics
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• v.3 no.1
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• pp.29-33
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• 1997

Four diamond films were deposited by the microwave plasma assisted chemical vapor deposition method varying CH4 concentration from 2.5 to 10% in the feeding gases. Thermal conductivity was measured on these free standing films by the steady state method from 80 K to 400K. They showed higher thermal conductivity as the film deposited with lower methane concentration. One exception, 7.79% methane concentration deposited film, was observed to be the highest thermal conductivity. Phonon scattering processes were considered to analyze the thermal conductivity with the full Callaway model. The grain size and the concentration of the extended and the point defects were used as the fitting parameters. Microstructure of diamond films was investigated with the scanning electron microscopy and Raman spectroscopy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.222-225
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• 2001

This paper describes design and performance test of dual-mode horn antenna for HAPS (High Altitude Platform Station) in 47.2 - 47.5 GHz and 47.9 - 48.2 GHz bands. To obtain the optimal geometry parameters of it. the conical section is represented by a stepped transition composed of a set of cylindrical waveguide sections. For each step. the corresponding generalized scattering matrix is calculated. The elements of the matrices at the open end of the horn, are calculated by the rigorous formulas of the factorization method. To verify the theoretical results, a horn breadboard was manufactured for the medium frequency of 47.7 GHz and its radiation beam patterns were measured. The calculated and theoretical results are in good agreement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.12
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• pp.9-14
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• 2000

A numerical method for scattering of electromagnetic waves from a arbitrary shaped grating covered with dielectric slab is considered for TE polarization case from the viewpoints of both reflection grating problem and leaky wave antenna problem. The analysis is based on a periodic Green's function and the method of moments. Numerical results involving some combinations of geometric parameters are presented in terms of relative scattered powers of spectral modes and complex propagation constants.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.159-162
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• 2004

Problems of overlap errors and sidelobe printing by the design rule reduction in the lithography process using attenuated phase-shifting masks(attPSM) have been serious. Overlap errors and sidelobes can be simultaneously solved by the rule-based correction using scattering bars with the rules extracted from test patterns. Process parameters affecting the attPSM lithography simulation have been determined by the fitting method to the process data. Overlap errors have been solved applying the correction rules to the metal patterns overlapped with contact/via. Moreover, the optimal insertion rule of the scattering bars has made it possible to suppress the sidelobes and to get additional pattern fidelity at the same time.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.73-77
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• 2018

This paper proposes a dual-band bandpass filter using stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with parallel coupled lines (PCLs) that have interdigital and comb-line shorted ends. The central PCLs build an upper passband and a transmission zero, and the two U-shaped SIRs build a lower passband. Four resonators and coupling structures are theoretically analyzed to derive its scattering parameters. A novel dual-band bandpass filter is designed and fabricated using the induced scattering characteristics. The measured results show that the fabricated dual-band bandpass filter has an insertion loss of less than 1.02 dB in the lower band of 2.45 GHz and of 3.01 dB in the upper band of 3.42 GHz, and a band-to-band isolation of more than 40 dB, from 3.14 to 3.2 GHz.

• Journal of the Korean Applied Science and Technology
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• v.16 no.4
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• pp.329-335
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• 1999

The influences of fluorophor, scatterer, and absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength. The molecular properties have been studied by laser induced fluorescence spectroscopy in phantom. It has been found that the effects of optical properties in scattering media could be investigated by the optical parameters(${\mu}_a$, ${\mu}_a$, ${\mu}_t$). Experimental and Monte Carlo Simulation method for modelling light transport in tissue was applied. The experimental results using a phantom were discussed and compared with those obtained through Monte Carlo Simulation. It may also aid in designing the best model for oil chemistry, medicine and application of medical engineering.

• Korean Journal of Remote Sensing
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• v.3 no.2
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• pp.89-102
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• 1987

Microwave remote sensing plays a major role in areas where cloud cover and darkness prevail. In this and the next paper, models are described for the radar backscatter from two major types of sea ice in an attempt to specify optimum sensor parameters and to allow the most reliable image interpretation possible. Here, the physical-optics model using an exponential correlation function is shown to be able to presict the signatures of first-year ice under cold conditions. The effect of volume scattering by small inclusions in the first-year ics is shown to be negligible using a semi-empirical volume scattering model.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.243-253
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• 2009

For the last 14 years, space-borne satellite SAR system such as RADARSAT-1, ERS-2, and ENVISAT ASAR have provided a continuous observation over the ocean. However, the data acquired from those systems were limited to C-band frequency until the advent of the first spacebome German X-band SAR system TerraSAR-X in 2007. Korea is also planning to launch the nation's first X-band SAR satellite (KOMPSAT-5) in 2010. It is timely and necessary to develop X-band models for estimating geophysical parameters from these X-band SAR systems. In this study, X-band wind retrieval model was investigated and developed based on numerical ocean scattering model (radar backscattering model and hydrodynamic interaction model). Although these models have not yet been tested and validated for broad ranges of wind conditions, the estimated wind speeds from TerraSAR-X data show generally good agreement with in-situ measurements.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.682-685
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• 1991

Solvent dependence of the static solution properties of a polymer chain was studied by static light scattering technique for polystyrene in three good solvents, toluene, tetrahydrofuran and $CCl_4$. The molecular parameters such as radius of gyration and second virial coefficients of polystyrene are found to be clearly larger in THF than the other two solvents and they are in the order of tetrahydrofuran > toluene > $CCl_4$. The radius of gyration shows the same order while the difference is smaller. Nontheless, the penetration functions are found to have a comparable value about 0.2, which confirms the universality of the penetration function in high expansion regime over different nature of solvents.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.435-441
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• 1988

The purpose of this study is to apply the zone method expressions for a gray, absorbing, emitting, and linearly anisotropic scattering medium enclosed in an infinite plane layer to evaluate heat transfer applications. The medium is assumed to be homogeneous and has a refractive index of unity. The boundary surfaces are opaque and gray, diffusely emitting and reflecting at a constant temperature. Radiative equilibrium condition, combined conductive and radiative heat transfer, and thermal ignition are studied in terms of the governing parameters, and the results are compared with previous studies. Wall heat flux results agree well with those of others. Except for the minor discrepancies observed for some cases, temperature results also agree well with those of previous studies. Good agreement with results from other methods indicates the accuracy of the zone method as well as its compatibility with other modes of heat transfer.