• Journal of the Korean Chemical Society
• /
• v.42 no.6
• /
• pp.664-671
• /
• 1998

Poly pyrrole polymer(ppy) has an excellent electrical conductivity and can be easily polymerized on anode to give various morophology according to doped anion on electroactive sites. To improve the properties of brittleness, ageing and hydrophobisity, poly furan polymer(pfu) having a high initiation potential was anodically implanted in this porous ppy film matrix to get the Pt/ppy/pfu(x)type of polymer composite electrode. Cyclic voltammetry and electrochemical impedance methods were used to these electrode, where $PF_6^-,\; BF_4^-$, and $ClO_4^-$ ions were employed as dopants. The composition of the pfu(x) at the electrode was changed from 0 to 1.10, but the range was useful only at 0.1 to 0.2 as the redox electrode. The polymer composite electrode doped with $PF_6^-$ was better in charge transfer resistance by a factor of 40 times and in double layer capacitance by a factor of 20 times than others. The charge transfer in the polymer film of the electrode was influenced on frequency change and equivalent circuit of this electrode had Warburg impedance including mass transfer.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.10 no.2 s.48
• /
• pp.11-19
• /
• 2006

In this paper the seismic performances of 4, 10, and 30-story staggered truss systems (STS) were evaluated by observing the force-displacement relationship up io failure. The results were compared with the seismic performance of conventional moment resisting frames and braced frames. According to the analysis results, the STS showed relatively satisfactory lateral load resisting capability. However, in the mid- to high-rise STS, plastic hinges formed first at the chords were transferred to vertical members of the vierendeel panels, which formed a week link and subsequently leaded to brittle collapse of the structure. Therefore to enhance the ductility of STS it would be necessary to reinforce the vertical bracing members of the virendeel panels so that the plastic hinges, once toned in cord members of a virendeel panel, spread out to virendeel panels of neighboring stories.

• 한국해양학회지
• /
• v.21 no.3
• /
• pp.146-155
• /
• 1986

Zooplankton samples of upper 50m layer in May, 1985 and of various depth intervals depending on thermal structure in October, 1985 were analyzed. Standing stock represents mean of 538inds/㎥ in spring and 267 inds/㎥ and 508inds/㎥ of whole column mean and surface layer in fall, respectively. A total of 55 and 104taxa is identified in each season and accumulated data list at least 123 species inhabiting in the study area. Copepods dominate in the zooplankton community, followed by protozoans and appendicularians in both seasons. In surface layer, distribution of subtropical species and standing stock seems to illuminate the effects of the Tsushima Current and the North Korean Cold Watermass in cold season, whereas only standing stock shows discernable variation in warm season. Concerning whole water column, depth of permanent thermocline bottom, at about 120m in fall 1985, plays significant role as a barrier to the distribution of mesopelagic cold water species. Serial sampling in October, 1985 does not reveal any perceivable diel vertical migration, which is considered to confirm the earlier suggest that owing to the lack of true abyssal species zooplankton biomass of deeper gayer is very poor, so that diel vertical migration of the East Sea is weak.

• Corrosion Science and Technology
• /
• v.11 no.3
• /
• pp.96-102
• /
• 2012

Outer diameter stress corrosion cracking (ODSCC) has occurred for Alloy 600 (Ni 75 wt%, Cr 15 wt%, Fe 10 wt%) as a heat exchanger tube of the steam generator (SG) in nuclear power plants (NPP) during long term operation. Among many causes for SCC, lead (Pb) is known to be one of the most deleterious species in the secondary system. In the present work, the oxide formed on Alloy 600 was characterized as a function of the PbO content in 0.1 M NaOH at $315^{\circ}C$ by using an electrochemical impedance spectroscopy (EIS), a transmission electron microscopy (TEM), equipped with an energy dispersive x-ray spectroscopy (EDS). The oxide property was analyzed in view of SCC susceptibility.

• Journal of the Korean Geographical Society
• /
• v.50 no.6
• /
• pp.621-639
• /
• 2015

The aim of this study is to consider the physical distribution system of assembly supplied from $1^{st}$ supplier and module corporation to automobile assembly plant through analysis of existing literatures and interview survey. The major findings of this study are as follows. Parts supply of automobile are to bind together with many regional parts supplier than using multi frequency and small delivery of JIT. Regional physical distribution center of joint parts and integrated physical distribution information center is to be installed in neighboring region of automobile assembly plant in order to reduce the transport cost by designating and activating multiple physical distribution and transport companies in each automobile assembly plant and turning into effective high volume shipping system.

• Korean Journal of Labor Studies
• /
• v.14 no.2
• /
• pp.309-346
• /
• 2008

이 논문에서는 호주에서 한국계 이주자가 다수 취업하고 있는 건설산업의 타일직종의 사례를 중심으로 한국계 이주노동자의 노동실태를 밝힌다. 건설현장의 사례조사를 통해 중층적 하청구조의 말단에 편성된 타일노동조직인 노무재하청업체의 작업방식 및 생산성관리, 숙련구분 및 임금결정, 임금수준 등 기타 노동조건을 구체적으로 규명한다. 그리고 이를 호주의 노사관계에서 제도화된 자영청부방식 및 자영청부공의 노동조건 등과 비교한다. 사례조사는 2006년도에 시드니지역 상업용 건축부문의 타일시공현장 두 곳을 대상으로 이뤄졌다. 두 곳의 건축현장 모두 노조가 활동하는 현장임에도 불구하고 한국계 이주 타일노동자는 공식적인 노사관계제도가 적용되지 않는 무협약상태에 있다. 건설산업의 최저 노동조건이라고 할 수 있는 전국재정 마저도 적용되고 있지 않다. 그들이 공식적인 노사관계제도의 적용으로부터 배제된 근본적인 이유는 타일회사로부터 타일시공을 다시 하수급하는 한국계의 노무재하청업체(오야까따)에 고용되어 있기 때문이다. 타일회사나 빌더는 1990년대 후반부터 다수 유입되기 시작한 한국계 타일공을 이와 같은 노무 재하청방식으로 사용하고 있는 것이다. 건설노조는 확대되는 노무재하청에 대해 한국계 타일노동자를 대상으로 한 여권조사, 임시고용비자 및 타일청부면허 취득 캠페인 등의 활동을 통해 불법취업자의 사용을 금지하는 한편 한국의 타일기능공을 자영타일공으로 전환시켜 노사관계 질서를 세우려 하였다. 그러나 이러한 노조의 활동에도 불구하고 기업협약에 의해서 명문으로 금지되고 있는 노무재하청의 관행이 전혀 개선되지 않고 있다. 노무재하청 관행에 대한 건설노조 정책의 가장 곤란한 문제점은 노무재하청을 행하는 당사자인 재하청업자를 한국계 타일노동자 조합조직의 중심으로 하고 있으며, 또 하지 않을 수 없는 점에 있음을 양국 간의 숙련구분 및 임금제도 비교분석을 통해 밝혔다.

• Ecology and Resilient Infrastructure
• /
• v.6 no.1
• /
• pp.12-22
• /
• 2019

This study investigated the spatial and temporal water circulation characteristics of Paldang Reservoir by continuous hydraulic and water temperature survey. Due to differences in water temperature and discharge pattern of Ipo Weir and Cheongpyeong Dam, the flow and temperature fluctuations were different in sections of Namhan River and Bukhan River in Paldang Reservoir. At the stratification period, the water temperature of the discharge of Ipo Weir was higher than that of the Cheongpyeong Dam. Therefore, in the surface layer of the downstream of Bukhan River, relatively high temperature water is located and back water phenomenon occurred, and convergence zone is formed. In the downstream section of Namhan River, low-temperature water was distributed in the middle and lower layers, and the upstream flow appeared to be difficult to mix with the surface layer.

• Korean Journal of Environment and Ecology
• /
• v.28 no.1
• /
• pp.55-61
• /
• 2014

To examine the forest structure and variation of samara and leaf shape of Acer pictum subsp. mono (APSM), We investigated forest structure and samara angles and length, and leaf shape in three natural population of APSM in Yanggu-gun, Youngyang-gun and Kwangyang-si from June 2012 to October 2013. Mean importance percentage (MIP) of APSM is shown lower values in Yanggu 19.8%, in Youngyang 22.0%, and in Kwangyang 17.1%, respectively. In middle layer, importance percentage (IP) of APSM is shown lower values than that of Acer pseudosieboldianum and Carpinus cordata. In lower layer, importance percentage (IP) of APSM is shown lower values in Yanggu 1.8%, in Youngyang 1.9%, and in Kwangyang 0.0%, respectively. From these results, MIP of APSM in natural population might be reduced in future. Angles between wings and samara length are significantly different between districts. APSM with seven palmate vein leaf are distributed more frequently at Kwangyang and Youngyang than Yanggu. Percentages of biserrate leaf is shown in Yanggu 0.6%, in Youngyang 15.8%, and in Kwangyang 20.4%, respectively. These results implies genetic variation in natural APSM population and further studies on the genetic variation analysis in natuel population of APSM should be needed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.2
• /
• pp.96-104
• /
• 2000

By using the offshore type submersible platform, Artificial sea floor anchored at a depth of forty meters several experimental studies have been conducted successfully during 1996. The facility consists of an artificial sea floor that floats at 7 meters below the surface, a machinery hut that projects above the surface at the center of the structure and a balance weight beneath the structure. The facility can be surfaced easily by using a water discharging pump in the water tank which is located at the center of it. To find out the behavioral character and the gathering factor of fishes around the artificial sea floor, investigations were carried out during the daytime and nighttime by direct observation and by echo-sounder. Around the testing reefs and artificial sea floor, six kinds of fishes were found by diving observation and the dominants were Scomber japonicus, Sebastes thompsoni and Oplegnathus fascitus. As Scomber japonicus was distributed around the artificial sea floor in dense small school, they were not seen elsewhere in the survey area. The artificial sea floor was concluded to act as a schooling ground far Scomber japonicus, Sebastes thompsoni and Oplegnathus fascitus. were close to the testing reefs(within 10m) in the daytime, and were thought to settle on the testing reefs at nighttime, To examine the distribution of 7shes around the artificial sea floor, an acoustic survey over a 1$\times$1km area, 0-50m in depth during the all day. Around the artificial sea floor many thin scattering fish echo(TS-54.5~ -51.5dB) and dense fish echo(TS-41~-38dB) were mainly distributed. Many scattering fish echoes, which were thought to be a mixture of small squid, pelegic crustacea and ethers, were distributed over the whole survey area. A dense fish school stayed beneath the artificial sea floor for a short duration. These phenomena were concluded to show an attraction and detention function of the artificial sea floor.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.28 no.4
• /
• pp.337-346
• /
• 1992

Hydroacoustic surveys were conducted in the East China Sea, in the summers of 1990-1991 to investigate the distribution and migration behavior of fish, such as the diel changes in the distributions of fish, the thermoselection behavior of fish, and the fish reactions to a surveying vessel. The hydroacoustic observations were taken with a scientific echo sounder operating at 50kHz and a microcomputer-based echo processor. Fish samples were collected by bottom trawling and temperature was measured with a DBT system. The patterns of fish distributions were compared with the vertical profiles of water temperature. The results obtained can be summarized as follows: 1. The time series of hydroacoustic observations on the downward migration at dawn in the central region of East China Sea showed that the migration rate was 0.24 m/min. In this region, most of the fish collected by bottom trawling during the surveys were squid (Photologio edulis f. budo) and horse mackeral (Trachurus japonicus). 2. The hydroacoustic observations, which together associated with temperature data, indicated that squid and horse mackeral concentrated nocturally in a narrow vertical band of thermocline, particularly in summer when the survey region was strongly stratified. This result suggest that the nocturnal vertical distribution of these species evidently is controlled by temperature. 3. When the survey vessel, that is running at a speed of 11 knots, has suddenly stopped, the fish which concentrated beneath the transducer showed a strong avoidance reaction in the form of rapid downward migration. After a few minutes, the descending reaction disappeared and the fish slowly began the upward migration toward their original swimming positions. Trawl data suggest that the fish, which showed the avoidance reaction, was Liparis tessellatus.