• Korean Journal of Medicinal Crop Science
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• v.15 no.3
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• pp.194-198
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• 2007

Yield and ginsenoside contents of ginseng (Panax ginseng C. A. Meyer) is affected by light intensity and quality, and the color and the thickness of PE shading net when PE net is utilized for shading material. This study was carried out to investigate the effect of light quality on root yield and ginsenoside contents off-year-old ginseng by using polyethylene shading net with each blue and yellow color, Spectral irradiance under blue and yellow shading net showed the peak at 498 nm and 606 nm, respectively, which made distinct difference in light quality. Heat injury ratio of blue shading net was increased distinctly more than that of yellow shading net in summer season because of higher transmitted quantum (23%)and air temperature (0.3 $^{\circ}$C) in blue shading net than those of yellow shading net. Chlorophyll content and leaf area under yellow shading net were higher than those of blue shading net, and its heat injury ratio was lower than those of blue. These effects may led to 48% higher increase of root yield under yellow shading net than that under blue shading net. The content of total ginsenoside in taproot was not significantly differed between blue and yellow shading net, while the content in lateral and fine root was significantly increased in blue shading net compared to yellow shading net. PDM ratio of blue shading net showed more significant increase in lateral root than that of yellow shading net. All of Rb$_1$/Rg$_1$ ratio in three parts of root under blue shading net was higher than that of yellow shading net, but there were no significant increase in the ratio of lateral root.

• Korean Journal of Remote Sensing
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• v.36 no.2_1
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• pp.155-165
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• 2020

In this present study, the sensitivity of O₄ Air Mass Factor (AMF) to Aerosol Peak Height (APH) has been investigated using radiative transfer model according to various parameters(wavelength (340 nm and 477 nm), aerosol type (smoke, dust, sulfate), aerosol optical depth (AOD), surface reflectance, solar zenith angle, and viewing zenith angle). In general, it was found that O₄ AMF at 477 nm is more sensitive to APH than that at 340 nm and is stably retrieved with low spectral fitting error in Differential Optical Absorption Spectroscopy (DOAS) analysis. In high AOD condition, sensitivity of O₄ AMF on APH tends to increase. O₄ AMF at 340 nm decreased with increasing solar zenith angle. This dependency isthought to be induced by the decrease in length of the light path where O₄ absorption occurs due to the shielding effect caused by Rayleigh and Mie scattering at high solar zenith angles above 40°. At 477 nm, as the solar zenith angle increased, multiple scattering caused by Rayleigh and Mie scattering partly leads to the increase of O₄ AMF in nonlinear function. Based on synthetic radiance, APHs have been retrieved using O₄ AMF. Additionally, the effect of AOD uncertainty on APH retrieval error has been investigated. Among three aerosol types, APH retrieval for sulfate type is found to have the largest APH retrieval error due to uncertainty of AOD. In the case of dust aerosol, it was found that the influence of AOD uncertainty is negligible. It indicates that aerosol types affect APH retrieval error since absorption scattering characteristics of each aerosol type are various.

• Elastomers and Composites
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• v.35 no.1
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• pp.46-52
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• 2000

Miscibility improvement between polypropylene(PP) and ethylene-propylene-diene-terpolymer (EPDM) was studied by introducing specific interaction into both polymers. PP was modified by grafting maleic anhydride(MAH) onto backbone, leading to MAH-grafted PP(PP-g-MAH). Sulfonated EPDM ionomer neutralized with bivalent zinc cation(ZnSEPDM) was used as one component. The blends of PP-g-MAH and ZnSEPDM were prepared at $200^{\circ}C$ in Brabender Roller Mixer. Fourier transform-infrared(FT-IR) spectroscopic and dynamic mechanical studies have been performed to investigate the miscibility. FT-IR spectral peak corresponding to carbonyl group in PP-g-MAH and that to sulfonate group in ZnSEPDM were shifted to lower and higher frequency with increasing ZnSEPDM content, respectively, in the blends. Glass transition temperature of ZnSEPDM was increased up to 70wt.% of ZnSEPDM, and again decreased above 70wt.%. It can be concluded from the shift of FT-IR characteristic peaks and the changes of glass transition temperatures that the miscibility between PP and EPDM was improved via introducing specific interaction, i.e., dipole-ion interaction.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.522-528
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• 2009

This study focused on establishing prediction models using visible-near infrared spectrum to simultaneously detect multiple components of soils and enhancing the performance quality by suitably transformed input spectra and classification of soil spectral types for prediction model input. The continuum-removed spectra showed significant result for all cases in terms of soil properties and classified or bulk predictions. The prediction model using classified soil spectra at an absorption peak area around 500nm and 950nm efficiently indicating soil color showed slightly better performance. Especially, Ca and CEC were well estimated by the classified prediction model at $R^{2}$ > 0.8. For organic carbon, both classified and bulk prediction model had a good performance with $R^{2}$ > 0.8 and RPD> 2. This prediction model may be applied in global soil mapping, soil classification, and remote sensing data analysis.

• Tunnel and Underground Space
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• v.19 no.6
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• pp.490-497
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• 2009

The horizontal and vertical response spectra using the observed ground motion from the recent 5 macro earthquakes were analysed and then were compared to both the seismic design response spectra(Reg Guide 1.60), applied to the domestic nuclear power plants, and the Korean Standard Design Response Spectrum for general structures and buildings(1997). 74 horizontal and 89 vertical observed ground motions, without considering soil types, were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that the horizontal MPOSD(Mean Plus One Sigma Standard Deviation) response spectra revealed much higher values for the whole frequency bands above 1 Hz than Reg. Guide(1.60). For the vertical response spectra, the results showed slightly higher than just between 7 and 8 Hz frequency band. The results were also compared to the Korean Standard Response Spectrum for the 3 different soil types and showed that the horizontal MPOSD response spectra revealed much higher values for the whole periods below 2 second(0.5 Hz) than those of SE soil type. The vertical response spectra showed similar to the values of the Korean Standard Response Spectrum of SD soil type. These spectral values dependent on frequency could be related to characteristics of the domestic crustal attenuation and the effect of each site amplification. However, through the qualitative improvements and quantitative enhancement of the observed ground motions, the conservation of horizontal seismic design response spectrum should be considered more significantly for the whole frequency bands above the 1 Hz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.33-35
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• 2008

We have fabricated and evaluated new high efficiency green light emitting phosphorescent devices with an emission layer of $[TCTA_{1/3}TAZ_{2/3}/TAZ]:Ir(ppy)_3$. The whole experimental devices have the basic structure of $2-TNATA(500 {\AA})/NPB(300{\AA})/EML(300{\AA})/BCP(50{\AA})/SFC137(500{\AA})$ between anode and cathode. We have also fabricated conventional phosphorescent devices with emission layers of $(TCTA_{1/3}TAZ_{2/3}):Ir(ppy)_3$ and $(TCTA/TAZ):Ir(ppy)_3$ and compared their electroluminescence characteristics with those of the device with an emission layer of $(TCTA/TCTA_{1/3}TAZ_{2/3}/TAZ):Ir(ppy)_3$. The current density(J), luminance(L), and current efficiency($\eta$) of the device with an emission layer of $(80{\AA}-TCTA/90{\AA}-TCTA_{1/3}TAZ_{2/3}/130{\AA}-TAZ):10%-Ir(ppy)_3$ were 95 $mA/cm^2$, 25000 $cd/m^2$, and 27 cd/A at an applied voltage of 10V, respectively. The maximum current efficiency was 52 cd/A under the luminance of 400 $cd/m^2$. The peak wavelength and FWHM(full width at half maximum) in the electroluminescence spectral were 513nm and 65nm, respectively. The color coordinate was (0.30, 0.62) on the CIE (Commission Internationale de l'Eclairage) chart. Under the luminance of 15000 $cd/m^2$, the current efficiency of the device with an emission layer of $(80{\AA}-TCTA/90{\AA}-TCTA_{1/3}TAZ_{2/3}/130{\AA}-TAZ):10%-Ir(ppy)_3$ was 34 cd/A, which has been improved 1.7 times and 1.4 limes compared to those of the devices with emission layers of $(300{\AA}-TCTA_{1/3}TAZ_{2/3}): 10%-Ir(ppy)_3$ and $(100{\AA}-TCTA/200{\AA}-TAZ):10%-Ir(ppy)_3$, respectively.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.227-234
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• 2010

The vertical response spectra using the observed ground motions from the recent more than 30 macro earthquakes were analysed and then were compared both to the seismic design response spectra (Reg Guide 1.60), applied to the domestic nuclear power plants, and to the Korean Standard Design Response Spectrum for general structures and buildings (1997). 176 vertical ground motions, without considering soil types, were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that response spectrum had strong dependency on epicentral distance. The results also showed that the vertical response spectra revealed much higher values for frequency bands above 5~7 Hz than Reg. Guide (1.60). The results were also compared to the Korean Standard Response Spectrum for the 3 different soil types and showed that the vertical response spectra revealed much higher values for the frequency bands below 0.2 second (5 Hz) than the Korean Standard Response Spectrum (SD soil condition). These frequency-dependent spectral values could be related to the characteristics of the domestic crustal attenuation and the effect of each site amplification. However, through the qualitative improvements and quantitative enhancement of the observed ground motions, the conservation of vertical seismic design response spectrum should be considered more significantly for the frequency bands above 5 Hz.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.201-213
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• 2015

Site effects resulting in the amplification of earthquake ground motion are strongly influenced not only by the subsurface soil conditions and structure, but also by the surface topography. Yet, over the last several decades, most studies of site-specific seismic responses in Korea have focused primarily on the seismic amplification associated with geologic and soil conditions. For example, the effects of local geology are now well established and have been incorporated into current Korean seismic design codes, whereas topographic effects have not been considered. To help address this shortcoming, two-dimensional (2D) seismic site response analyses, using finite element (FE) ground modeling with three different slope angles, were performed in order to assess the site effects of surface topography. We then compared our results, specifically peak ground acceleration (PGA) and acceleration response spectrum, to those of one-dimensional (1D) FE model analyses conducted alongside our study. Throughout much of the upper slope region, PGAs and spectral accelerations are larger in the 2D analyses than in the 1D analyses as a result of the topographic effect.

• Korean Journal of Materials Research
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• v.18 no.7
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• pp.347-351
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• 2008

We have fabricated and evaluated newNew high high-efficiency green green-light light-emitting phosphorescent devices with an emission layer of [$TCTA/TCTA_{1/3}TAZ_{2/3}/TAZ$] : $Ir(ppy)_3$ were fabricated and evaluated, and compared the electroluminescence characteristics of these devices were compared with the conventional phosphorescent devices with emission layers of ($TCTA_{1/3}TAZ_{2/3}$) : $Ir(ppy)_3$ and (TCTA/TAZ) : $Ir(ppy)_3$. The current density, luminance, and current efficiency of the a device with an emission layer of ($80{\AA}-TCTA/90^{\circ}{\AA}-TCTA_{1/3}TAZ_{2/3}/130{\AA}-TAZ$) : 10%-$Ir(ppy)_3$ were $95\;mA/cm^2$, $25000\;cd/m^2$, and 27 cd/A at an applied voltage of 10 V, respectively. The maximum current efficiency was 52 cd/A under the a luminance value of $400\;cd/m^2$. The peak wavelength and FWHM (FWHM (full width at half maximum) in the electroluminescence spectral were 513 nm and 65 nm, respectively. The color coordinate was (0.30, 0.62) on the CIE (Commission Internationale de I'Eclairage) chart. Under the a luminance of $15000\;cd/m^2$, the current efficiency of the a device with an emission layer of ($80{\AA}-TCTA/90{\AA}-TCTA_{1/3}TAZ_{2/3}/130{\AA}-TAZ$) : 10%-$Ir(ppy)_3$ was 34 cd/A, which has beenshowed an improvement of improved 1.7 and 1.4 times compared to those of the devices with emission layers of ($300{\AA}-TCTA_{1/3}TAZ_{2/3}$) : 10%-$Ir(ppy)_3$ and ($100{\AA}-TCTA/200{\AA}$-TAZ) : 10%-$Ir(ppy)_3$, respectively.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.5 s.311
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• pp.79-87
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• 2006

In this study, we evaluated the performance of a companding strategy as a preprocessing for speech enhancement and noise reduction. The proposed algorithm is based on two tone suppression that is human's hearing characteristics. This algorithm enhances spectral peak of speech signal and reduces background noise, however it has tradeoff characteristics between speech distortion and noise reduction due to limited channel number and nonlinear block. Therefore, we designed two different companding structures that have relative characteristics of noise reduction and speech distortion and found suitable companding structures by difference of individual speech perception ability in noise environment. Thus we proposed speech perception enhancement of cochlear implant user in noise environment with low SNR. The performance of the proposed algorithm was evaluated through 5 normal hearing listeners using noise band simulation. Improvement of speech perception was observed for all subjects and each subject preferred the different type of companding structure.