• Journal of Sericultural and Entomological Science
• /
• v.27 no.2
• /
• pp.47-53
• /
• 1985

The studies on the reaction of Urea-Formaldehyde(UF) resin with silk fabric were studied, and the final results summarized as below; 1. The pH and UF molar ratio for preparing liquid resin was found at pH 4-5 and UF molar ration 1:2 and above. 2. The weight gains were increased with respect to increase in concentration of UF resin solution, while moisture regains were decreased. 3. The weight gains were significant high in case of wet pick up 70%. 4. The weight gains were increased with respect to increase in curing temperature and the amount of catalyst((NH4)2SO4) found was 2.5% on the weight of Dimethylol urea and Hydrochloric acid was 1%, Tartaric acid was 10%. 5. The effect of different catalyst on wash fastness of UF resin was good where as in case of acidic catalyst was significantly high. 6. The weight gains with different catalyst was high where as in case of potential acid catalyst was significantly high. 7. The crease recovery are increased with the increase of the weight gain of silk fabric and also stiffness are increased.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.4
• /
• pp.795-802
• /
• 2011

In this paper, the detailed design procedure of the Y-junction stripline isolator self-contained the filter circuit in the center conductor in order to maximize attenuations below value of 30 dB at 3rd order harmonics is presented. The HFSS is used to simulate 1.8GHz band isolator and the results are compared with the measurement data. These results confirms that the designed stripline isolator is effective in achieving high attenuation above -30 dB at 3rd order harmonics. And it is obtained that the harmonic band of isolator using the ferrite of 0.16T is moved far from operating frequency more 1.2 GHz than one using the ferrite of 0.12T.

• Journal of Korea Multimedia Society
• /
• v.15 no.3
• /
• pp.364-371
• /
• 2012

Currently, CMMB(China Mobile Multimedia Broadcasting) and the conventional analog TV broadcasting have transmitted by using UHF(Ultra High Frequency : 474MHz~754MHz) band. Normally, the transmission power of the digital TV broadcasting is lower than the conventional analog TV broadcasting to protect the reception quality of the conventional analog TV broadcasting. The reception sensitivity of CMMB receiver has severely deteriorated due to adjacent the conventional analog TV broadcasting signals which called ACI (Adjacent Channel Interference). To improve the reception sensitivity of a CMMB receiver on ACI environment, this paper proposed a simple method which is tuning a cut off frequency of LPF (Low Pass Filter). From the experiment, the reception sensitivity of CMMB receiver was improved as 11.3dB.

• Polymer(Korea)
• /
• v.31 no.6
• /
• pp.461-468
• /
• 2007

In order to understand the structure of the existing aggregate in the nanocomposite, which has been prepared with polyester and trisilanolisobutyl polyhedral oligomeric silsesquioxane(TBPOSS), laser light scattering(LLS) and SEM-EDS were applied to its 1,1,1,3,3,3-hexafluoro-2-propanol solution and original sample, respectively. Although aggregate particles appeared as spherical shape of the average diameter of 120 nm in SEM image, they were not microgels but almost linear copolymer chains ($M_w=2.3{\times}10^6\;g/mol$) alternating 320 molecules of TBPOSS with polyester subchains. It has been microphase-separated from the matrix polyester due to the difference of chemical composition. As the matrix, polyester chain of $M_w=4.0{\times}10^4\;g/mol$ had averagely 2.5 molecules of TBPOSS per chain. It is also found that about 93% of total TBPOSS molecules existed in matrix phase and the residual 7% in spherically aggregated phase.

• Spatial Information Research
• /
• v.10 no.2
• /
• pp.331-343
• /
• 2002

Recently, as various fields of applications using space-borne imagery have been emphasized, interests on integrated analysis or fusion using multi-sources are also increasing. In this study, to investigate applicability of multiple imageries for further regional-scaled application, DN value analysis and multi-resolution classification by using KOMPSAT EOC imagery and Landsat 7 ETM+image data in the Namyangju-city area were performed, and then this classified results were compared to land-use thematic data at the same area. In case of classified results by using muff-resolution image data, it is shown that linear-type features can be easily extracted. furthermore, it is expected that multi-resolution classified image can be effectively utilized to urban environment analysis, according to results of similar pattern by comparative study based on multi-buffered zone analysis or so-called distance analysis along main road features in the study area.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.6
• /
• pp.21-27
• /
• 1999

In this work, single-poly EEPROM was designed and fabricated by using standard $0.8{\mu}m$ CMOS process. From the results of programming and erasing characteristics, it was found that the programming time was smaller than 10ms and the erasing time was about 100ms. To reduce the erasing time, several erasing methods were performed. The S/D erasing method was used to improve the endurance characteristics which was degraded due to electron trapping in programming and erasing cycles. By using the S/D erasing method, the more improved endurance characteristics then conventional one was obtained.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.432-435
• /
• 2006

To evaluate geology and extent of leachate migration around the landfills, electrical resistivity survey were conducted in area of uncontrolled landfills in Cheonan and Wonju. The Cheonan landfill is located above the paddy fields and the resistivity survey lines were crossed to confirm possible pollution of the paddy fields by leakage of the landfill leachate. In Wonju, the landfill and the downgradient paddy fields are divided by a concrete barrier wall. At the bottom of the landfill, there is a leachate settlement system but has not been in operation. And a total of 4 survey line installed (1 parallel and 3 perpendicular to mean groundwater flow direction). According to the resistivity survey results, the landfill leachate in Cheonan appeared to be restricted only within the interior of the landfill, not to migrate into the subsurface of the paddy fields. These results are well consistent with electrical conductivity values of groundwaters obtained from a periodic analysis of water qualities. In Wonju, however, it was inferred that the leachate emanating from the landfill migrated beneath the abandoned leachate settlement system and it would reach the downgradient paddy field.

• The Journal of Engineering Geology
• /
• v.17 no.4
• /
• pp.623-631
• /
• 2007

In this paper, dynamic elastic module of banded gneiss were calculated on the basis of SPS velocity logging data obtained from a geotechnical test-hole in Pungsan-dong, Hanam, Gyeonggi Province, Korea. This study mainly focuses on the velocity analysis, Q factor calculation relative to attenuation factor, and generation of crack information and its relation with seismic velocity. As a result, P-wave and S-wave velocity of fresh hard rock was 5,559m/s and 3,063m/s, respectively, with Poisson's ratio being 0.28. With these results, dynamic modules were prepared, and crack information analyzed by acoustic televiewer was incorporated to identify the correlation among and between delay of first arrival by crack amplitude ratio, and velocity. The results of this study revealed that the analyzed logging hole mainly consisted of micro crack and a number of cracks and the size of crack aperture, functioned as a variable to seismic velocity in the micro crack area of this type of hard rock.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.9
• /
• pp.4261-4266
• /
• 2011

Polypropylene (PP)/talc compounds with talc content of 20wt% were fabricated by master-batch (MB) and direct compounding method using injection molding. The MB was prepared by mini compounder at $200^{\circ}C$ and the content of talc was 50wt%. The talc dispersion of the PP/talc compound was investigated by SEM-EDS. The talc was well dispersed within PP matrix in case of the MB-PP compound using MB. The rheological properties of the PP/talc compounds were measured by dynamic Rheometer. The MB-PP compound indicates higher shear thinning and elastic property than direct compound. The disperion of talc was certified by G'-G" plot, and Van Gurp-Palmen analysis was applied in order to certify an increase in elasticity.

• Journal of Soil and Groundwater Environment
• /
• v.27 no.spc
• /
• pp.19-33
• /
• 2022

When subsurface is polluted, contaminants tend to migrate through groundwater flow path. The groundwater flow path is highly dependent upon underground geological structures in the contaminated area. Geophysical survey is an useful tool to identify subsurface geological structure. In addition, geophysical logging in a borehole precisely provides detailed information about geological characteristics in vicinity of the borehole, including fractures, lithology, and groundwater level. In this work, surface seismic refraction and electrical resistivity surveys were conducted in a test site located in Namyangju city, South Korea, along with well logging tests in five boreholes installed in the site. Geophysical data and well logging data were collected and processed to construct an 3D geological map in the site.