• Journal of the Korean earth science society
• /
• v.27 no.1
• /
• pp.83-94
• /
• 2006

The objective of this paper is to extract and analyze the sediment environment change information in the Sachencheon, Gangneung, Korea that was seriously damaged as a result of typhoon Rusa aftermath early in September, 2002 using multi-temporal remote sensing data. For the extraction of change information, an unsupervised approach based on the automatic determination of thresholding values was applied. As the change detection results, turbidity changes right after typhoon Rusa, the decrease of wetlands, the increase of dry sand and channel width and changes of relative level in the stream due to seasonal variation were observed. Sedimentation in the cultivated areas and restoration works also affected the change near the Sacheoncheon. In addition to the change detection analysis, several environmental thematic maps including microtopographic map, distributions of estimated amount of flood deposits and flood hazard landform classification map were generated by using remote sensing and field survey data. In conclusion, multi-temporal remote sensing data can be effectively used for natural hazard analysis and damage information extraction and specific data processing techniques for high-resolution remote sensing data should also be developed.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.2
• /
• pp.146-151
• /
• 2010

In order to improve T-N and T-P removal in HF (horizontal flow)-HF hybrid constructed wetlands by natural purification method for treating the hydroponic wastewater in greenhouses, the efficiency of water treatment as affected by the injection method of hydroponic wastewater, the addition of special filter media, the particle size of filter media, and the injection ratio of hydroponic wastewater in $1^{st}$ HF and $2^{nd}$ HF beds were investigated in small-scale HF-HF hydroponic wastewater treatment apparatus. Removal rate of T-P in the water in HF-HF hydroponic wastewater treatment apparatus with calcite as affected by addition method of special filter media was higher than that in HF-HF hydroponic wastewater treatment apparatus with other filter media. Removal rate of BOD, COD, SS, T-N and T-P in the water in mixed filter media with calcite were 86, 84, 87, 50 and 97%, respectively. Removals of pollutants except for T-P in the water were slightly different. Therefore, it should be considered that the removal rate of T-P was good for calcite in HF-HF hydroponic wastewater treatment apparatus. To improve T-N and T-P removal, the optimum particle size of filter media was 1.2 mm, and the optimum injection ratio ($1^{st}$ HF bed : $2^{nd}$ HF bed) of hydroponic wastewater was 60:40.

• Korean Journal of Weed Science
• /
• v.15 no.3
• /
• pp.197-205
• /
• 1995

The objectives of the present study were to find out 1)the differences in growth of radish under foggy and non-foggy condition, 2)the weed competition between radish and major upland weeds including Echinochloa crus-galli, 3)difference in response of radish to herbicide and weed, and finally 4)the fundamental data for the establishment of radish weed control system under locational foggy regions. The research was carried out by tray in greenhouse equipped with Auto Foggy System(SAE KI RIN Co.) and results were summarized as follows. 1. Plant height and shoot fresh weight of radish cultivars(long skirt, delicious altari, green mascot) were not different at the early growth(8 to 38 days after seeding), but increased at 55 days after seeding under foggy condition. Root fresh weight increased only in green mascot cultivar tinder foggy condition. Chlorophyll contents were higher in all the cultivars of radish under foggy condition. 2. Plant height and shoot fresh weight increased at 0 and 20 days of weed competition under foggy condition. Root fresh weight increased at 0, 20 and 35 days of competition under foggy condition. Above 50 days-competition, there was no difference between foggy and non-foggy condition. 3. Napropamide, alachlor and linuron did not show any differences in plant height and shoot fresh weight between foggy and non-foggy condition. Molinate reduced the root fresh weight at 65 days after seeding tinder foggy condition. 4. No difference in weeding efficacy by any herbicides tested was found tinder foggy condition. Weeding efficacy of Aeschynomene indica was reduced under foggy condition.

• The Korean Journal of Mycology
• /
• v.10 no.1
• /
• pp.7-13
• /
• 1982

Habit characteristics of imperfect and perfect stage of D. bryoniae encountered on naturally infected seeds of cucumber and pumpkin were studied by the blotter method and compared with those grown on Difco potato dextrose agar (PDA), V-8 juice agar and water agar leaf medium (WALM). Most of the pycnidiospores obtained from each isolate of this fungus grown on PDA were non-septate and microtype. Non-septate pycnidiospores were predominanted in all isolates, but a macrotype of the non-septate and a number of uniseptate pycnidiospores were produced on V-8 juice agar and water agar leaf medium. On seed the pycnidiospores were mostly non -septate, but rarely uniseptate ones were also found. On radicle of cucumber seed, the pycnidiospores were non-septate and uniseptate but small percentage biseptate with somewhat constricted at septa. Pycnidiospores produced on V-8 juice agar and water agar leaf medium were similar to those produced on seeds. In the present investigation the perithecia were mostly globose to subglobose with apical papillate ostiole and whitish spore masses formed on the ostiole of perithecia, either on naturally infected seed or on culture media. The mature perithecia were dark brown to black. They were partially embedded or erumpent on seed coat and culture media. The perithecia varied in size within a much narrower range than the pycnidia. But perithecial formation of this fungus on PDA, V-8 juice agar, WALM and seed varied considerably depending upon isolate and culture media.

• Korean Journal of Ecology and Environment
• /
• v.35 no.3 s.99
• /
• pp.152-159
• /
• 2002

The seasonal variations of nitrifying bacterial population sampled from 3 sites in Moon-Chon reservoir were analyzed by in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes from August 2000 until July 2001. In addition, physico-chemical parameters such as temperature, pH, chi-a and DOC were measured to determine correlations between those factors and the size of nitrifying bacterial populations. Total bacterial numbers varied in the range of $0.8{\sim}1.5{\times}10^6\;cells/ml$ independent of sites and had the maximal values in March at all 3 stations. The ratio of eubacteria to total bacteria ranged from 44.9% to 79.5%, and the ratio of each nitrifying bacteria to eubacterial numbers reached only $1.0{\sim}7.4%$. The variations of ammonia-oxidizing bacteria ranged from $1.1{\times}10^4$ to $3.0{\times}10^4\;cells/ml$ without noticeable peak values whereas those of nitrite-oxidizing bacteria varied in $1.3{\sim}5.7{\times}10^4\;cells/ml$ with the increasing tendency in winter regardless of the sites. Moreover it was observed that the numbers of nitrite-oxidizing bacteria were higher than those of ammonia-oxidizing bacteria. Total bacterial numbers correlated with water temperature (r = 0.355, p<0.05) and DOC (r = 0.58G, p<0.01) positively whereas nitrite-oxidizing bacteria correlated with temperature (r = -0.416, p<0.05) and pH (r = -0.568, p = 0.001) negatively. In addition, DOC represented good correlations with eubacterial numbers (r = 0.448, p<0.01). These results indicate that temperature, DOC and pH might be one of the main factors affecting variations of bacterial populations in the aquatic ecosystem. It was also suggested that FISH method is a useful tool for detection of slow growing nitrifying bacteria.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.2
• /
• pp.272-279
• /
• 2012

In order to effectively treat livestock wastewater in constructed wetlands by natural purification method, removal velocities of pollutants under different injection methods in constructed wetlands were investigated. The removal velocities of chemical oxygen demand (COD), suspended solid (SS), T-N and T-P by continuous injection method were slightly rapid than those by intermittent injection method in full-scale livestock wastewater treatment plant. The removal velocity (K; $day^{-1}$) of COD by continuous injection method was $0.38\;d^{-1}$ for $1^{st}$ bed, $0.13\;d^{-1}$ for $2^{nd}$ bed, $0.17\;d^{-1}$ for $3^{rd}$ bed, $0.05\;d^{-1}$ for $4^{th}$ bed and $0.17\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of COD in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.210\;d^{-1}$, $0.086\;d^{-1}$, $0.222\;d^{-1}$, $0.053\;d^{-1}$ and $0.137\;d^{-1}$, respectively. The removal velocity (K; $day^{-1}$) of SS by continuous injection method was $0.750\;d^{-1}$ for $1^{st}$ bed, $0.108\;d^{-1}$ for $2^{nd}$ bed, $0.120\;d^{-1}$ for $3^{rd}$ bed, $0.086\;d^{-1}$ for $4^{th}$ bed and $0.292\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of SS in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.485\;d^{-1}$, $0.056\;d^{-1}$, $0.174\;d^{-1}$, $0.081\;d^{-1}$ and $0.227\;d^{-1}$, respectively. The removal velocity (K; $day^{-1}$) of T-N by continuous injection method was $0.361\;d^{-1}$ for $1^{st}$ bed, $0.121\;d^{-1}$ for $2^{nd}$ bed, $109\;d^{-1}$ for $3^{rd}$ bed, $0.047\;d^{-1}$ for $4^{th}$ bed and $0.155\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of T-N in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.235\;d^{-1}$, $0.071\;d^{-1}$, $0.171\;d^{-1}$, $0.058\;d^{-1}$ and $0.126\;d^{-1}$, respectively. The removal velocity (K; $day^{-1}$) of T-P by continuous injection method was $0.803\;d^{-1}$ for $1^{st}$ bed, $0.084\;d^{-1}$ for $2^{nd}$ bed, $0.076\;d^{-1}$ for $3^{rd}$ bed, $0.118\;d^{-1}$ for $4^{th}$ bed and $0.301\;d^{-1}$ for $5^{th}$ bed. The removal velocities (K; $day^{-1}$) of T-P in $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$ and $5^{th}$ beds by intermittent injection method were $0.572\;d^{-1}$, $0.049\;d^{-1}$, $0.090\;d^{-1}$, $0.112\;d^{-1}$ and $0.222\;d^{-1}$, respectively.

• Korean Journal of Organic Agriculture
• /
• v.25 no.4
• /
• pp.843-859
• /
• 2017

The JK-1 isolate which was the best producer of indole-3-acetic acid and carotenoid among the 388 strains isolated from 28 wetlands in Jeju, was identified to be Rhodopseudomonas palustirs belongs to a typical group of non sulfur purple bacteria based on 16S sRNA sequencing. This study investigated the effect of different cultural conditions of pH, temperature, agitation, light and aeration on growth, IAA and carotenoid production of photosynthetic bacterium JK-1 for optimization of IAA and carotenoid production. It was found that growth, IAA, carotenoid, and bacteriochlorophyll production with light (3,000~3,500 Lux) and agitation (100 rpm) showed better results than those with dark/static or dark/agitation (100 rpm) in anaerobic conditions. The optimal pH, temperature and agitation speed for cell growth were 7, $30^{\circ}C$, 150 rpm, for IAA production were 9, $30^{\circ}C$, 150rpm and for carotenoid production were 6, $25^{\circ}C$, 50 rpm, cultured for 72 h under anaerobic light, respectively. The growth and IAA production were high in aerobic culture compared with anaerocic culture, whereas carotenoid and bacteriochlorophyll content were decreased extremely in aerobic condition (0.5~1 vvm). Subsequently, the optimal culture conditions for JK-1 were selected with pH 7, $30^{\circ}C$ and 100 rpm under anaerobic light and the effect on plant growth was tested by pot assay. Inoculation of JK-1 with 3% (v/v) level caused increase in shoot and root dry weigh that varied from 20%~58% to 40%~28% in young radish in camparison to uninoculated treatment at 50 days of growth. The study suggests that the JK-1 isolate may serve as efficient biofertilizer inoculants to promote plant growth.

• Journal of Life Science
• /
• v.29 no.1
• /
• pp.60-68
• /
• 2019

Limonium tetragonum, an edible halophyte that grows on salt marshes in Korea, is thought to possess various health benefits (e.g., antioxidant, antitumor, and hepatoprotective). In the present study, different solvent partitioned subfractions, water ($H_2O$), buthanol (n-BuOH), 85% aqueous methanol (85% aq. MeOH), and hexane (n-hexane), from crude extract of L. tetragonum were tested for their ability to prevent adipogenesis in differentiating 3T3-L1 preadipocytes. The treatment of differentiating 3T3-L1 preadipocytes with L. tetragonum subfractions (LTFs) resulted in suppressed adipogenesis and reduced expression of adipogenesis-related transcription factors such as peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), CCAATT/enhancer-binding protein alpha ($C/EBP{\alpha}$), and sterol regulatory element-binding protein 1c (SREBP-1c) at both mRNA and protein levels. In addition, the LTF treatment notably decreased the levels of phosphorylated p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) of the mitogen-activated protein kinase (MAPK) pathway in association with $PPAR{\gamma}$-linked adipogenesis. Among all the tested LTFs, $H_2O$ and n-hexane were the most effective in lowering lipid accumulation and regulating the adipocyte differentiation via $PPAR{\gamma}$ pathway. Taken together, the results indicated that the $H_2O$ and n-hexane LTFs contain bioactive compounds that may exhibit significant antiadipogenesis activity by downregulation of the $PPAR{\gamma}$ pathway and inactivation of the MAPK signal pathway in 3T3-L1 preadipocytes.

• Korean Journal of Heritage: History & Science
• /
• v.49 no.2
• /
• pp.56-69
• /
• 2016

Flame resistant treatment has been applied since 1973 for fire prevention in historical wooden buildings, but several problems, such as whitening and discoloration are constantly occurring in some Dancheong, in spite of evaluation criteria. It is supposed that these phenomena are caused by the stability issue of flame retardant, Dancheong production methods, the residue of chemicals, which were applied in the past, building location environments, etc., but no evaluation and cause inspection has been performed. Therefore, this study aims to verify the effect of flame retardant on Dancheong by producing Pseudo-samples and setting spatial and temporal environment conditions. Pseudo-samples of Dancheong were produced using three methods; the method specified in the Standard Specification of Properties; the method, which is generally used in the site and the traditional method. For different environment conditions of pseudo-samples, the areas were classified into a coastal area and an inland area and the places were classified into a sunny place and a wetland. After applying a flame retardant, annual variations were inspected for 12 months and change aspects were observed through scan and regular observation. In annual variation inspection, various variations like whitening, decolorization, dissolution and exfoliation were found and especially, whitening was most dominant. When the effect of flame retardant depending on the production methods was analyzed, whitening occurred in all the three production methods. It is supposed that this is because calcium(Ca) was contained in the coloring material of each production method and it reacted with phosphorous(P) of flame retardant. When the effect of flame retardant depending on the environment conditions was analyzed, whitening occurred more in the coastal area than in the inland area and it reduced in the building in a sunny place, which was constructed using the traditional method. It is supposed that this results from the humidity change and the difference of glue used in each production method. In conclusion, for using a flame retardant containing phosphorous(P), there is a need to check if calcium components including Oyster Shell White were used in Dancheong in advance and to conduct various preliminary studies on place conditions and Dancheong construction conditions.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.36 no.5
• /
• pp.407-428
• /
• 1991

The eastern coastal area having variability of climate is located within Taebaek mountain range and the east coast of Korea. It is therefore ease to cause the wind damages in paddy field during rice growing season. The wind damages to rice plant in this area were mainly caused by the Fohn wind (dry and hot wind) blowing over the Taebaek mountain range and the cold humid wind from the coast. The dry wind cause such as the white head, broken leaves, cut-leaves, dried leaves, shattering of grain, glume discolouration and lodging, On the other hand the cold humid wind derived from Ootsuku air mass in summer cause such symptom as the poor rice growth, degeneration of rachis brenches and poor ripening. To minimize the wind damages and utilize as a preparatory data for wind injury of rice in future, several experiments such as the selection of wind resistant variety to wind damage, determination of optimum transplanting date, improvement of fertilizer application methods, improvement of soils and effect of wind break net were carried out for 8 years from 1982 to 1989 in the eastern coastal area. The results obtained are summarized as follows. 1. According to available statisical data from Korean meteorological services (1954-1989) it is apperent that cold humid winds frequently cause damage to rice fields from August 10th to September 10th, it is therefore advisable to plan rice cultivation in such a way that the heading date should not be later than August 10th. 2. During the rice production season, two winds cause severe damage to the rice fields in eastern coastal area of Korea. One is the Fohn winds blowing over the Taebaek mountain range and the other is the cold humid wind form the coast. The frequency of occurrence of each wind was 25%. 3. To avoid damage caused by typhoon winds three different varieties of rice were planted at various areas. 4. In the eastern coastal area of Korea, the optimum ripening temperature for rice was about 22.2$^{\circ}C$ and the optimum heading date wad August 10th. The optimum transplanting time for the earily maturity variety was June 10th., medium maturity variety was May 20th and that of late maturity was May 10th by means of growing days degree (GDD) from transplanting date to heading date. 5.38% of this coastal area is sandy loamy soil while 28% is high humus soil. These soil types are very poor for rice cultivation. In this coastal area, the water table is high, the drainage is poor and the water temperature is low. The low water temperature makes it difficult for urea to dissolve, as a result rice growth was delayed, and the rice plant became sterile. But over application of urea resulted in blast disease in rice plants. It is therefore advise that Ammonium sulphate is used in this area instead of urea. 6. The low temperature of the soil inhibits activities of microorganism for phosphorus utilization so the rice plant could not easily absorb the phosphorus in the soil. Therefore phosphorus should be applied in splits from transplanting to panicle initiation rather than based application. 7. Wind damage was severe in the sandy loamy soil as compared to clay soils. With the application of silicate. compost and soil from mointain area. the sand loamy soil was improved for rice grain colour and ripening. 8. The use of wind break nets created a mocro-climate such as increased air. soil and water temperature as well as the reduction of wind velocity by 30%. This hastened rice growth, reduced white head and glume discolouration. improved rice quality and increased yield. 9. Two meter high wind break net was used around the rice experimental fields and the top of it. The material was polyethylene sheets. The optimum spacing was 0.5Cm x 0.5Cm. and that of setting up the wind break net was before panicle initiation. With this set up, the field was avoided off th cold humid wind and the Fohn. The yield in the treatment was 20% higher than the control. 10. After typhoon, paddy field was irrigated deeply and water was sprayed to reduce white head, glume discolouration, so rice yield was increased because of increasing ripening ratio and 1, 000 grain weight.