• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.21 no.4
• /
• pp.75-86
• /
• 2018

This research was thereby made to study and analysis ecological, landscape, and stability qualities of roadside cut Slopes in expressways and national highways that went through revegetation works. Also, evaluation items and framework for integrated assessment of plant structure and restored state for the maintenance were suggested. Following is the summary of the result. firstly, for stabilization of introduced native plant species on roadside cut slops, assessment on the post-project environmental management through long-term monitoring and maintenance works must be made. It signifies a form of authentic recovery and restoration by the native plants. second, current evaluation framework on the test beds is well managed with clear evaluation standards and table while its method of assessing the post management with only test bed results lacks conformity with this study site. Newly developed evaluation framework on the post construction sites is estimated to be used as assessment standards on any roadside construction sites. Third, after site investigation distinction was observed among different revegetating construction types in the long-term perspective. Due to the different duration time of vegetation state between seed-spray measures(degraded in time) and layer-spray measure(maintained), the use of coarse straw-mat mulching work or Coir net was suggested in long term maintenance of cut slopes. forth, segmentation of post environmental assessment is organized into three large categories of "ecological", "stabile", and "landscape" qualities regarding post restoration quality and stability of slope through native plants with which categories marks 50, 30, 20 points of rates. fifth, components of the post environmental assessment were segmented in twelve categories driving results from former experimental construction and newly focused items on site. In the future, it is possible to propose a customized assessment method considering the location and location of construction work if the research on the application of post-environment assessment methods for road construction surface recording is conducted systematically.

• Analytical Science and Technology
• /
• v.11 no.6
• /
• pp.478-484
• /
• 1998

Distribution of polyphenolic compounds in oak tree (Quercus acutissima, three years old) collected from Forest Research Institute located in Kwang Leung, Kyeonggi-do, Korea, was investigated using chromatographic studies. Total 25 polyphenolic fractions were separated from an oak tree, of which 15, 11, 7, 7, and 4 were in leaf, stem, root, bark, and seed, respectively. Catechins are predominant compounds in the polyphenols and some flavonoids were also identified. Distribution of polyphenols was relatively different in each part. Polyphenols in all of the part studied, except leaf where polymer was not detected, were existed as polymeric, oligomeric, and monomeric forms. Relative contents of total polyphenols in Quercus acutissima were the highest in bark, followed by root, leaf, acorn, and stem. Monomeric polyphenols were the predominant compounds present in all of the part of the oak tree.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.4
• /
• pp.45-50
• /
• 2006

Copper via filling is the important factor in 3-D stacking interconnection of SiP (system in package). As the packaging density is getting higher, the size of via is getting smaller. When DC electroplating is applied, a defect-free hole cannot be obtained in a small size via hole. To prevent the defects in holes, pulse and pulse reverse current was applied in copper via filling. The holes, $20\and\;50{\mu}m$ in diameter and $100{\sim}190\;{\mu}m$ in height. The holes were prepared by DRIE method. Ta was sputtered for copper diffusion barrier followed by copper seed layer IMP sputtering. Via specimen were filled by DC, pulse and pulse-reverse current electroplating methods. The effects of additives and current types on copper deposits were investigated. Vertical and horizontal cross section of via were observed by SEM to find the defects in via. When pulse-reverse electroplating method was used, defect free via were successfully obtained.

• Journal of the Microelectronics and Packaging Society
• /
• v.7 no.3
• /
• pp.31-36
• /
• 2000

We developed embedded inductors in MCM-D substrate for RF applications. The increasing demand for high density packaging was the driving forces to the development of MCM-D technology. Most of these development efforts have been focused on high performance digital circuits. However, recently there is a great need fur mixed mode circuits with a combination of digital, analog and microwave devices. Mixed mode modules often have a large number of passive components that are connected to a small number of active devices. Integration of passive components into the high density MCM substrate becomes desirable to further reduce cost, size, and weight of electronic systems while improving their performance and reliability. The proposed MCM-D substrate was based on Cu/photosensitive BCB multilayer and Ti/Cu is used to form the interconnect layer. Seed metal was formed with 1000 $\AA$ Ti/3000 $\AA$ Cu by sputtering method and main metal was formed with 3 $\mu\textrm{m}$ Cu by electrical plating method. The multi-turn sprial inductors were designed in coplanar fashion. This paper describe the manufacturing process of integrated inductors in MCM-D substrate and the results of electrical performance test.

• Food Science and Preservation
• /
• v.7 no.3
• /
• pp.291-296
• /
• 2000

The present study was conducted to investigate antioxidant, nitrite scavenging and alcohol degradation effects of extracts from leaf and fruit stalk of Hovenia dulcis. Yields of various solvent extracts for Hovenia dulcis leaf and fruit stalk of were higher in water and methanol extract layer, respectively. Ethanol extracts of Hovenia dulcis leaf and fruit stalk of were fractionated with different solvents such as hexane, chloroform, ethyl acetate, butanol and water, yields of water fraction were highest. In the solvent extracts using methanol, ethanol, hexane, chloroform and water, ethanol extracts showed the most effective antioxidant and nitrite-scavenging effects. Ethanol extracts from Hovenia dulcis leaf and fruit stalk of were fractionated, the most natioxidant and nitrite-scavenging effects were ethyl acetate fraction. Alcohol degradation effects from different parts of Hovenia dulcis showed higher leaf and fruit stalk than xylem, branch and seed. Alcohol degradation effects from leaf and fruit stalk increased as time passed.

• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.2 s.35
• /
• pp.129-134
• /
• 2005

Electroplating copper is the important role in formation of 3D stacking interconnection in SiP (System in Package). The I-V characteristics curves are investigated at different electrolyte conditions. Inhibitor and accelerator are used simultaneously to investigate the effects of additives. Three different sizes of via are tested. All via were prepared with RIE (reactive ion etching) method. Via's diameter are 50, 75, $100{\mu}m$ and the height is $100{\mu}m$. Inside via, Ta was deposited for diffusion barrier and Cu was deposited fer seed layer using magnetron sputtering method. DC, pulse and pulse revere current are used in this study. With DC, via cannot be filled without defects. Pulse plating can improve the filling patterns however it cannot completely filled copper without defects. Via was filled completely without defects using pulse-reverse electroplating method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.7
• /
• pp.502-509
• /
• 2018

Epitaxial ZnO nanowires (NWs) were synthesized on sapphire (001) substrates using a hydrothermal process. The effects of the pH value of the precursor solution on the structural and optical properties of the resulting NWs was studied. The epitaxial relationship and the domain matching configuration between the sapphire (001) substrate and the as-grown ZnO NWs were determined using synchrotron X-ray diffraction measurements. The (002) plane of $w{\ddot{u}}rtzite$ ZnO NW grows in the surface normal direction parallel to the sapphire (001) direction. However, three types of in-plane domain matching configurations were observed, such as the on-position, $30^{\circ}$-rotated position, and ${\pm}8.5^{\circ}$-rotated position relative to the on-position, which might be attributed to inheriting the in-plane domain configuration of the ZnO seed layer.

• Korean Journal of Materials Research
• /
• v.24 no.1
• /
• pp.19-24
• /
• 2014

We report the nitrogen monoxide (NO) gas sensing properties of p-type CuO-nanorod-based gas sensors. We synthesized the p-type CuO nanorods with breadth of about 30 nm and length of about 330 nm by a hydrothermal method using an as-deposited CuO seed layer prepared on a $Si/SiO_2$ substrate by the sputtering method. We fabricated polycrystalline CuO nanorod arrays at $80^{\circ}C$ under the hydrothermal condition of 1:1 morality ratio between copper nitrate trihydrate [$Cu(NO_2)_2{\cdot}3H_2O$] and hexamethylenetetramine ($C_6H_{12}N_4$). Structural characterizations revealed that we prepared the pure CuO nanorod array of a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the gas sensing measurements that the p-type CuO nanorod gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as $200^{\circ}C$. We also found that these CuO nanorod gas sensors showed reversible and reliable electrical response to NO gas at a range of operating temperatures. These results would indicate some potential applications of the p-type semiconductor CuO nanorods as promising sensing materials for gas sensors, including various types of p-n junction gas sensors.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.86-89
• /
• 2004

The present study reports the preparation of a compact ZSM-5 membrane showing high thermal stability and high separation factors, especially n-/i-butane isomers at high temperatures. ZSM-5 membrane was prepared on a porous $\alpha$-Al$_2$O$_3$ tube (an average pore diameter, ca. 100 nm) at 18$0^{\circ}C$ by the seed-assisted crystallization method. The XRD and SEM results showed that a thin zeolite layer (ca. 1 ${\mu}{\textrm}{m}$) was formed on the support surface. The single gas permeances of $N_2$, H$_2$, SF$_{6}$, n-butane, and i-butane were taken at 27$0^{\circ}C$. i-Butane permeance hardly changed after repeated thermal treatments up to 40$0^{\circ}C$, indicating the membrane is thermally stable. On the other hand, other single gas permeances increased when the membrane was further dried at 40$0^{\circ}C$, indicating thermal pretreatment at 27$0^{\circ}C$ could not remove all the adsorbed species in the membrane. i-Butane and SF$_{6}$ permeances were significantly lower than the permeances of smaller molecules, indicating that the membrane has a low concentration of defects. The ideal selectivities at 27$0^{\circ}C$ were 61 for $H_2$/i-butane and 47 for $H_2$/SF$_{6}$. The temperature dependency of n/i-butane ideal selectivities and separation factors for an equimolar n/i-butane mixture was studied. The ideal selectivity showed a maximum of 36 at 30$0^{\circ}C$. The separation factors increased with temperature and reached around 12 at 300-40$0^{\circ}C$, which were much higher than those reported in the literature.ature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.33-33
• /
• 2007

SoP-L 공정은 유전율이 상이한 재료를 이용하여 PCB 공정이 가능하고 다른 packaging 방법에 비해 공정 시간과 비용이 절약되는 잠정이 있다. 본 연구에서는 SoP-L 기술을 이용하여 Si 기판의 함몰에 판한 공정의 안정도와 함몰 시 제작된 때턴의 특성의 변화에 대해 관찰 하였다. Si 기판의 함몰에 Active device를 이용하여 특성의 변화를 살펴보고 공정의 안정도를 확립하려 했지만 Active device는 측정 시 bias의 확보와 특성의 민감한 변화로 인해 비교적 측정이 용이하고 공정의 test 지표를 삼기 위해 passive device 를 구현하여 함몰해 보았다. Passive device 의 제작 과정은 Si 기판 위에 spin coating을 통해 PI(Poly Imide)를 10um로 적층한 후에 Cr과 Au를 seed layer로 증착을 하였다. 그리고 photo lithography 공정을 통하여 photo resister patterning 후에 전해 Cu 도금을 거쳐 CPW 구조로 $50{\Omega}$ line 과 inductor를 형성하였다. 제작 된 passive device의 함몰 전 특성 추출 data와 SoP-L공정을 통한 함몰 후 추출 data 비교를 통해 특성의 변화와 공정의 안정도를 확립하였다. 차후 안정된 SoP-L 공정을 이용하여 Active device를 함몰 한다면 특성의 변화 없이 size 룰 줄이는 효과와 외부 자극에 신뢰도가 강한 기판이 제작 될 것으로 예상된다.