• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.4
• /
• pp.2391-2400
• /
• 2015

Weather proof steels are used for steel bridges due to its high corrosion resistance under atmospheric conditions. However, instead of forming stabilized rust layers, general rust occurs on weather proof steels under high humidity condition close to seawater or shady places. In Japan, therefore, they perform rust stabilization treatment instead of unpainted treatment due to severe atmospheric conditions. However, most of domestic weather proof steels were constructed unpainted in the form of closed box-girder, which makes the periodical repetition of dry and wet hard to occur. For the steel bridges constructed on the Han river, the evaporation of water, dew condensation due to temperature change, and stagnant water due to rain affect harmfully on the formation of passive film on weather proof steels. Thus, in this research, in order to analyze corrosion properties inside the closed box-girder for the unpainted weather proof steel bridge in the waterworks safety zone, multiple ways of analysis such as observation with eyes, cellophane-tape test, steel thickness measurement, surface corrosion potential measurement, electron microscope analysis, and X-ray diffraction analysis of the rust were performed. As a result, unstable rust layer was observed inside the closed box-girder, and severe corrosion was observed on the top and bottom of the flanges due to the effects of stagnant water caused by rain, dew condensation, and de-icing materials.

• Korean Journal of Environmental Biology
• /
• v.17 no.2
• /
• pp.199-204
• /
• 1999

The effects of temperature stress and paraquat on the superoxide dismutase (SOD) activity and the photochemical efficiency of photosystem II were studied in the leaves of Araliaceae plants. The SOD activity of Acanthopanax koreanum leaf discs increased at 4$^{\circ}C$ and 28$^{\circ}C$, and increased significantly at 4$^{\circ}C$ ,28$^{\circ}C$ and 35$^{\circ}C$ in the presence of paraquat. However, the SOD activity of Dendropanax morbifera leaf discs decreased at 4$^{\circ}C$, 28$^{\circ}C$ and 35$^{\circ}C$ regardless of paraquat treatment. The photochemical efficiency of photosystem II, Fv/Fm, of leaf discs of A. koreanum and D. morbifera fell remarkably at 35$^{\circ}C$. In the presence of paraquat, the Ev/Fm values fell slightly at 4$^{\circ}C$ in A. koreanum leaf discs and at 35$^{\circ}C$, in D. morbifera leaf discs. These results indicate that A. koreanum plants are more resistant to temperature stress or oxidative stress than D. morbifera plants although their photochemical efficiency falls slightly at 4$^{\circ}C$ in the presence of paraquat.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.13 no.3
• /
• pp.177-183
• /
• 1993

This study was conducted to obtain the transformed tobacco plants with S. cerevisiae Acid phosphatase gene(PH05) using Agrobacterium tumefaciens and th confirm plant transformation and gene expression. the results obtained were summarized as follows: APase activity of Saccharomyces cereviase NA 87-11A was remarkably showed up as deep red color when assayed by Tohe and Oshima(1974). PH05 fragment, Apase gene, was obtained from pVC727G and the graphically estimated size was about 1.5kb by agarose gel electrophoresis. The sequencing results of 5'end and 3'end of PH05 using dideoxy chain termination method were coinsided with the full length nucleotide already. pBKJ I vector was constructed by isolation of PH05 fragment from pVC727-1 and pBKSI-1 digesred with Sma I and Xba I. Isolated plasmid from transformed A. tumefaciens with constructed pBKJ I when it was electrophoresed with agarose gel. The dosc of tobacco leaf was cocultivated 재소 transformed Agronacterium tumefaciens. Transformed shoots were selected on kanamtcin-containing MS-n/B medium and they were regenerated. The transgenic tobacco plants were elucidated by isolation of genomic DNA and genomic southern hybridization using ${\alpha}-^{32}P$ labelled PH05 fragments. The PH05 in transformed tobacco plants was expressed in leaf, stem and root, and its APase activity was estimated as deep red color by Tohe method.

• Asian Journal of Turfgrass Science
• /
• v.18 no.1
• /
• pp.15-27
• /
• 2004

For the study of ecophysiological characteristics of ground cover plant with shade tolerance, the material productivity and the growh characteristics were analyzed in Hosta clausa community at experimental farm of Kemyung College from March to October. The installation of experimental plots were split into control plot (full sunlight), 30%, 50%, 70%, shading rate by completely randomized design method. After the transplant, to take into account the edge effect of plant population, the plants were selected from each plot by random sampling every 10days. The following results were obtained; Then number of leaf, length of leaf and width of leaf length of leafstack remarkably showed high tendency under 30%, 50% shading plot as compared with control, 70% shading plot for the exmination as the process of develpment. They showed characteristics as herbaceous ground with shade tolerance under conparatively low the light condition and they ettain a stabilized development.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.3
• /
• pp.227-232
• /
• 2014

Ageratina altissima is an invasive plant species known to threaten native plant communities in Korea. A. altissima is thought to invade shady forests from disturbed open areas; however, uncertainty remains as to how shade and litter depth might affect establishment. A study of A. altissima distribution characteristics in areas adjacent to trails was undertaken at Mt. Umyeon in Seoul, Korea. Increasing densities of A. altissima were found to correlate with greater light availability and decreasing litter depth (p < 0.001) within 10 m distance from trail locations and on ridges rather than further within forests and valleys. The effects of soil moisture content, soil gravel content and soil pH on distribution were not found to be significant, suggesting that A. altissima is adaptable to a broad range of soil conditions. Results indicate that forest areas close to trails may be particularly susceptible place to A. altissima invasion, demonstrating the need to carefully consider implications for A. altissima expansion in trail management.

• Journal of the Korean association of regional geographers
• /
• v.14 no.5
• /
• pp.587-603
• /
• 2008

The Woong-Chi region is located between Wan-ju and Jin-an had experienced transportation route change from past continuously. The difference of relative height especially steep slope of western side is given to the most difficulty for transportation route open in Woong-Chi region. For the overcome this restraint geomorphological condition, multi-route were developed according to available purpose in walking period. They effort to decrease of slope and curve in route continual1y, and only used the conditioned route for automobile from 1910s in automobile period. The social aspect in transportation route change on this region is, firstly, the transportation route has trend from variety to simplicity. Secondary, new transportation route is opened by social needs such as traffic accident and social big event. Thirdly, the regional range was extended for overcome restraint condition. Fourthly, the rise and fall of route related settlement is influenced by transportation route change. The used technical method for the overcome the geomorphological condition is make a tunnel, alleviate the curve radius, alleviate the slop and consider the direction of the sunny than shady side.

• The Journal of Engineering Geology
• /
• v.16 no.4 s.50
• /
• pp.337-349
• /
• 2006

Seven hundred and fifty one fractures of the rhyolitic tuffaceous rock masses were mapped using 6 scanlines placed on rock slope exposures that were within 8.02 km of Busan-Ulsan highway. These data were analyzed to find the number of fracture sets that exist in the rock slopes and the probability distributions of orientation, spacing, trace length and fracture size in 3-D for each of the fracture sets. All the fracture set orientation distributions exhibit high variability. The Fisher distributions were found to be unsuitable to represent the statistical distribution of orientation for most of the fracture sets. The probability distributions, gamma, exponential and lognormal were found to be highly suitable to represent the distribution of spacing and semi-trace length of fracture sets. In obtain-ing these distributions, corrections were applied for sampling biases associated with spacing and trace length. The generated fracture system in 3-D was used to make predictions of fracture traces for each fracture set on 2-D win-dows. Developed stochastic 3-D fracture network for the rock mass was validated by comparing statistical proper-ties of the observed fracture traces on scanlines with the predicted fracture traces on the scanlines. This exercise fumed out to be successful.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.02a
• /
• pp.35-41
• /
• 2002

본 연구는 기존 벼 펠렛종자 제조장치의 제조성능 및 제조 벼 펠렛종자 품질향상을 위하여 펠렛재료 공급부, 성형부, 펠렛종자 배출부를 개선 설계 제작하여 그 성능과 제조 벼 펠렛종자 특성을 구명함으로써 직파용 벼 펠렛종자 대량생산을 위한 제조장치 개발의 기초 자료를 얻고자 수행하였으며 그 주요 결과를 요약하면 다음과 같다. 펠렛재료의 일정한 공급과 펠렛재료가 성형 홈으로부터의 이탈하는 것을 줄이고, 펠렛종자의 완전한 배출이 가능하도록 한 벼 펠렛종자 제조장치를 설계·제작하였으며, 벼 펠렛종자 제조장치를 상토 종자혼합비, 성형롤의 회전속도에 따라 실험한 결과 벼 펠렛종자 제조 능력은 성능 개선 전의 펠렛종자 제조장치에 비하언 약 1.7배 향상된 제조능력을 보였으며, 성형률은 최대 약 89 %로 나타나 개선 전의 71%에 비해 18 %정도 성형률이 향상되었다. 그러나, 벼 종자손실률은 약 24% ∼ 49%로 거의 비슷한 수준인 것으로 나타났다. 제조된 벼 펠렛종자의 특성을 분석한 결과 펠렛종자의 구형률은 99.1%로 거의 구형으로 제조됨을 알 수 있었으며, 무게는 제조 직후에는 약 1.70 g, 완전 건조 후에는 1.31 g으로 나타났고, 직경은 약 12.03 mm에서 건조 후 11.53 mm로 축소되었다. 개선 전에 비해 직경과 무게가 약간씩 증가한 것으로 나타났다. 이러한 결과는 재선된 제조장치에서 펠렛재료가 성형롤의 성형 홈에 압축 공급되고, 펠렛재료의 손실도 적었기 때문으로 판단된다. 제조된 한 개의 벼 펠렛종자 내에 포함된 완전 벼 종자의 개수는 상토 종자혼합비가 커질수록 성형롤의 회전속도가 낮을수록 많아지는 것으로 분석되었으며, 모두 펠렛종자 당 평균 약 3 개 이상의 완전 벼 종자를 포함하고 있는 것으로 나타났다. 개선 전에 비하여 펠렛종자 내에 포함된 평균 완전 종자수도 증가하였으며, 3개 이상 완전 종자를 포함한 펠렛종자의 비율도 증가하여 유압에 의한 펠렛재료 공급과 성형롤의 개선효과가 있었던 것으로 보인다. 음지 건조 후 벼 펠렛종자의 압축강도는 약 132 N ∼ 152 N으로 조사되었으며, 개선전에 비하면, 약 30 %가 증가한 것으로 나타났다. 출아율 실험 결과 상토 종자혼합비 6 : 1, 성형롤 회전속도 7 rpm에서 건답직파는 100%, 답수직파는 97 %의 출아율을 보여 만족할 만한 결과를 얻었으나, 그 외의 경우는 거의 90 % 이하의 출아율을 보여 출아율을 높이기 위한 방안이 필요한 것으로 보인다. 본 연구의 벼 펠렛종자 제조장치의 적정운전 조건은 제조된 벼 펠렛종자의 특성과 출아율을 고려해 볼 때 상토 종자혼합비 6 : 1, 성형롤 회전속도 약 7 rpm으로 판단되며, 이 때 제조능력은 시간당 약 65 Kg(펠렛종자 약 39,000 개), 성형률 약 87 %, 종자손실률은 약 30 %, 펠렛종자 내 평균 종자수는 약 5.5 개, 완전 벼 종자 3개 이상 포함 펠렛종자 비율은 약 100 %가 될 것으로 보인다.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.14 no.2
• /
• pp.79-89
• /
• 2012

This study was conducted to investigate the chlorophyll contents, photosynthetic characteristics, chlorophyll fluorescence, and growth performance of Parasenecio firmus under changing light environment. Parasenecio firmus was grown under non-treated (full sunlight) and three different shading conditions (88~93%, 65~75% and 45%~55% of full sunlight) for the experiment. Total chlorophyll content, photochemical efficiency (Fv/Fm), T/R ratio, specific leaf area (SLA), leaf area ratio (LAR), and leaf weight ratio (LWR) were increased with increasing shading level, but decreased dark respiration. Therefore, light absorption and light utilization efficiency were improved under the low intensity light. Plants under 65~75% of full sunlight had best maximum photosynthetic rate and net apparent quantum yield in May. On the other hand, the non-treated plants had lower maximum photosynthetic rate, photochemical efficiency, and chlorophyll content than the treated ones. Parasenecio firmus considered to be a sciophyte, is fairly sensitive to high intensity light. If 88-93% of full sunlight lasts for a long period, photosynthetic capacity will be sharply decreased, though limiting light. These results suggest that growth of Parasenecio firmus adapted to 65~75% of full sunlight.

• Parasites, Hosts and Diseases
• /
• v.36 no.1
• /
• pp.1-6
• /
• 1998

An epidemiological survey was carried out to determine the first intermediate host of Clinostomum complanatum among freshwater snails in Korea. Two species of snails belonging to the family Lymnaeidae were collected in Kaum-ji (pond) , Uisong-gun, Kyongsangbuk-do. Twelve (0.9%) out of 1,273 Radiae auricularia corecna examined were found to liberate cercariae of C. complcnatum, which were identified by morphologital characteristics and experimental infections in freshwater fish, Pseunorosborc pnnjc. The cercariae were brevifurcate and clinostomatoid. They had a transparent dorsal fin, a well developed penetrating organ and a pair of eye spots. The body measured $119-147{\;}{\times}{\;}33-36{\mu\textrm{m}}$, tail stem, tailstem은 $275-370{\;}{\times}{\;}19-26{\;}{\mu\textrm{m}}$, and furcae, $72-104{\;}{\mu\textrm{m}}$. Rediae were demonstrated in the infected snail after crushing. Redia, $527-1,630{\;}{\mu\textrm{m}}$ long and 121-368${\;}{\mu\textrm{m}}$ wide, contained 10-45 germ balls and cercariae in various developmental stapes. The metacercariae recovered from fish experimentally infected with C. complanntum cercariae were morphologically identical to those from naturally infected fish.