• Korean Journal of Ecology and Environment
• /
• v.50 no.4
• /
• pp.459-469
• /
• 2017

Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of denitrification bacteria method (Pseudomonas chlororaphis ssp. Aureofaciens ($ATCC^{(R)}$ 13985)), three reference (IAEA-NO-3 (Potassium nitrate $KNO_3$), USGS34 (Potassium nitrate $KNO_3$), USGS35 (Sodium nitrate $KNO_3$)) were analyzed 5 times repeatedly. Measured the ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values of IAEA-NO-3, USGS 34 and USGS35 were ${\delta}^{15}N:4.7{\pm}0.1$‰ ${\delta}^{18}O:25.6{\pm}0.5$‰, ${\delta}^{15}N:-1.8{\pm}0.1$‰ ${\delta}^{18}O:-27.8{\pm}0.4$‰, and ${\delta}^{15}N:2.7{\pm}0.2$‰ ${\delta}^{18}O:57.5{\pm}0.7$‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated isotope values of potential nitrogen source (soil, synthetic fertilizer and organic-animal manures) and temporal patterns of ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values in river samples during from May to December. ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values are enriched in December suggesting that organic-animal manures should be one of the main N sources in those areas. The current study clarifies the reliability of denitrification bacteria method and the usefulness of stable isotopic techniques to trace the anthropogenic nitrogen source in freshwater ecosystem.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.5
• /
• pp.610-617
• /
• 2016

Current study was performed to investigate the effect of morphological properties of black ginseng such as size and shape on the quality of black ginseng. The raw ginsengs were separated based on size (medium, large, and extra-large) and shape (straight ginseng, fibrous root ginseng). Subsequently, the raw ginsengs were steamed at $95^{\circ}C$ for 3 h and dried in the presence of heated air at $50^{\circ}C$ for 30 h. This process was repeated nine times for black ginseng production. The physiochemical properties such as the content of acidic polysaccharides, ginsenosides, and antioxidative activity were evaluated. Although minor difference in physiochemical properties such as acidic polysaccharide content in raw ginseng was observed, no statistical difference in the content of acidic polysaccharides, total phenols, and ginsenosides was observed during final black ginseng production based on size classification. The minor ginsenosides in fibrous root black ginseng, such as Rk3, Rh4, Rg3, Rk1, and Rg5 were higher in content than straight black ginseng. However, no correlation between the shape of ginseng and total phenol content and antioxidative activity was observed. Therefore, present results demonstrate that the difference in ginseng size in same-age and -production area does not affect the quality of black ginseng. Furthermore, difference in ginseng shape does not influence the overall quality of black ginseng. It is hypothesized that this study would be considered as supportive data for the production of high-quality black ginseng.

• International Journal of Highway Engineering
• /
• v.8 no.4 s.30
• /
• pp.49-62
• /
• 2006

The republic of korea has put a great emphasis on the role of the road as widening a social infra-structural facility. Thus, vast amount of money has been invested on the road establishment. As a result, there has been fruitful outcomes in establishing the road system of the nation especially for the flat road with ease. However, in order to have more systematic and sustainable road system, we should turn our attention to more painful and high-cost regions such as mountainous districts and those are to be developed effectively. The configuration of the road is an important factor to be considered in making a decision for the road planning. Nevertheless, current road planning criterion has no such clarified and objective judging standard for figuring the configuration of the road out and, as a result, speed planning can be decided incorrectly. our research has acknowledged the necessity of estimating the configuration of the road and aimed to make it organized and sorted according to the height, slope, and the vehicle's speed. The results are as follows. First, our research made use of GIS data and classified the road into 9 different areas according to the height and the slope. Also, road classification being matched to the data of vehicle's speed, it has been shown that those characteristics of different areas have made an influence on vehicle's speed. Secondly, based on the results of the similarity between geographical classification and, vehicle's speed of sorted groups according to the height and the slope, conclusively we have classified as flat, rolling region and mountain. Since our research has made use of vehicle's speed for National Highway, it is not applicable to different functional highways. However, for the highway to be established hereafter, it can be a standard for reflection geographical characteristics.

• Korean Security Journal
• /
• no.23
• /
• pp.21-39
• /
• 2010

The dangerous impact on the traffic flows of cars is caused by no only the construction on the street but diverse construction sites. This in turn substantially influence on the citizens and pedestrians, thereby bring about the possibility of giant incidents. As the countermeasure for the problem in advanced countries, particularly in Japan "traffic inducement security system" has been implemented. It is analyzed that the death toll from traffic accidents has considerably declined. In the case of South Korea the system has not been administered but restrictively executed at some construction sites; however proceeding it with the lack of professionalism. The introduction of traffic inducement security system would be the opportunity for South Korea to make a progress in the safety culture such as traffic security and traffic jam. This study thus aims at analyzing the advanced countries' cases, conducting comparative analysis with Korea's scheme, and establishing the plan to adopt the traffic inducement security system. Through the output of this study followings were proposed as plans of introducing the traffic inducement security system. First of all, legal assessments regarding traffic inducement operation, for example adding the operation of the system into the category of security service, need to be preceded prior to its introduction secondly, the traffic inducement security is the institution which can contribute to the improvement of traffic safety, and also internalizing social cost. therefore, it needs to be equipped with the new qualification such as the instruction with the standardized traffic safety map, instruction system, curriculum and the publication of teaching materials. thirdly, the education for the guard should be proceeded with dividing academic and technical ones with specific curriculum. At the fourth, the securement of the venue for the driving training, the determination on technical instruction contents and the training professional instructor needs for the method of administration. In addition, the efforts on the overal standardization of traffic inducement security is necessary, and it also requires constant collaboration among private security industry, academia, professionals, relavant research institutes, etc. At the last but the least, henceforth it is prerequisite that the networking system with a diverse array of associated entities due to its social ripple effect and job creation effect.

• Journal of Korean Society of Transportation
• /
• v.29 no.5
• /
• pp.121-138
• /
• 2011

More affordable and available cutting-edge technologies (e.g., wireless vehicle communication) are regarded as a possible alternative to the fixed infrastructure-based traffic information system requiring the expensive infrastructure investments and mostly implemented in the uninterrupted freeway network with limited spatial system expansion. This paper develops an advanced decentralized traveler information System (ATIS) using vehicle-to-vehicle (V2V) communication system whose performance (drivers' travel time savings) are enhanced by three complementary functions (autonomous automatic incident detection algorithm, reliable sample size function, and driver behavior model) and evaluates it in the typical $6{\times}6$ urban grid network with non-recurrent traffic state (traffic incident) with the varying key parameters (traffic flow, communication radio range, and penetration ratio), employing the off-the-shelf microscopic simulation model (VISSIM) under the ideal vehicle communication environment. Simulation outputs indicate that as the three key parameters are increased more participating vehicles are involved for traffic data propagation in the less communication groups at the faster data dissemination speed. Also, participating vehicles saved their travel time by dynamically updating the up-to-date traffic states and searching for the new route. Focusing on the travel time difference of (instant) re-routing vehicles, lower traffic flow cases saved more time than higher traffic flow ones. This is because a relatively small number of vehicles in 300vph case re-route during the most system-efficient time period (the early time of the traffic incident) but more vehicles in 514vph case re-route during less system-efficient time period, even after the incident is resolved. Also, normally re-routings on the network-entering links saved more travel time than any other places inside the network except the case where the direct effect of traffic incident triggers vehicle re-routings during the effective incident time period and the location and direction of the incident link determines the spatial distribution of re-routing vehicles.

• Korean Journal of Organic Agriculture
• /
• v.9 no.2
• /
• pp.101-115
• /
• 2001

Nitrogen applied as fertilizer for crop production is partly absorbed by plant , and the remaining nitrogen in soil might be leached out through complicated processes to the subsoil layer Especially, NO$_3$-N in leachate causes environmental pollution. The purpose of this study was focused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when nitrogen fertilizer and completely decomposed compost were applied. Lysimeters(Volume 0.15㎥, Diameter 62cm, Height 62.8cm) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments : fallow, fallow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications(16, 32, 64kg/10a), three N fertilizer and compost soil surface applications(16+800, 32+1600, 64+32kg/10a), two water dissolved N fertilizer applications(16, 32kg/10a), and low and high plant densities. N fertilizer was applied as urea. The growth of com(preceding crop) and potatoes(succeeding crop) and leaching loss were determined during the experimental period. The results obtained were summarized as follows ; With Increased N, pH of leachate tended to decrease and NO$_3$-N concentration of leachate increased. NO$_3$-N leaching loss was remarkably greater in soil from the bare plot without fertilization and the weed control than from plots with medium N rate and was least in the cropping plot without fertilization. NO$_3$-N concentration in leachates from the water dissolved N fertilizer application plots was 64% of that from the soil surface application plots. The concentration of Ca and K ions and the leaching loss of these ions were least from the cropping plot without fertilization and were greatest from bare plots(T1 and T2) without fertilization. The proportion of leaching and residual N in soil increased as N rate increased indicting that higher N rates increase the possibility of N leaching to subsoil layer The proportion of N leaching losses was lower at the low N rate and the high plant density. In future, fertilization prescription which can maximize fertilizer use efficiency and minimize the pollution of ground water will be needed for conserving the environments.

• Korean Journal of Microbiology
• /
• v.40 no.4
• /
• pp.342-347
• /
• 2004

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.

• Korean Journal of Environmental Agriculture
• /
• v.36 no.2
• /
• pp.87-96
• /
• 2017

BACKGROUND: The objective of this study was to identify and compare the main phenolic compounds (anthocyanins, flavonoids, phenolic acids) in blueberry and black raspberry cultivated in Korea using ultra-performance liquid chromatography diode array detection-quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS). METHODS AND RESULTS: Twenty-nine flavonoids were identified by comparison of ultraviolet and mass spectra with data in a chemical library and published data. Blueberry contained flavonols including kaempferol, quercetin, isorhamnetin, myricetin, and syringetin aglycones. Isorhamnetin 3-O-robinobioside, kaempferol 3-O-(6"-O-acetyl)glucoside, quercetin, quercetin 3-O-arabinofuranoside (avicularin), quercetin 3-O-(6''-O-malonyl) glucoside, and quercetin 3-O-robinobioside were detected for the first time in blueberry. The flavonoids in raspberry consisted of quercetin aglycone and its glycosides. The mean total flavonoid content in blueberry [143.0 mg/100 g dry weight (DW)] was 1.5-times that in raspberry (95.4 mg/100 g DW). The most abundant flavonoid in blueberry was quercetin 3-O-galactoside (hyperoside, up to 76.1 mg/100 g DW) and that in raspberry was quercetin 3-O-glucuronide (miquelianin, up to 55.5 mg/100 g DW). Miquelianin was not detected in blueberry. CONCLUSION: Flavonol glycosides were the main flavonoids in blueberry and black raspberry cultivated in Korea. The composition and contents of flavonoids differed between blueberry and black raspberry, and may be affected by the cultivar and cultivation conditions.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.2 no.3
• /
• pp.10-17
• /
• 1999

In order to confirm the effectiveness of the natural river improvement technique, the analysis of vegetation was carried out in Yangjae stream between 1996 and 1998. The results of this study showed the numbers of riparian plants had increased from 41 species to 53 species, and the dominant species had changed from annual and biannual(Humulus japonicus, Persicaria thunbergii, Persicaria hydropiper, Panicum dichotomiflorum, Echinochloa crus-galli) to perennials (Phragmites communis). The variation in biomass and biodiversity index were measured and calculated according to the rehabilitation method. Biomass were varied 302 to $828g/m^2$ and biodiversity index was varied 1.53 to 1.52 at point bar plots(A treatment plots) from 1996 to 1998. In conclusion, the natural river improvement technique which has operated in Yanjaecheon for three years has contributed to restoration of riparian plants. Additionally, subsequent study using this technique should be followed in the near future.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.3
• /
• pp.196-203
• /
• 1999

To establish the best rice cultivating system in the aspects of environment-loving agriculture, the amounts and patterns of nitrogen leached in the paddy soil were investigated with 7 treatments; Recommendation(R), Farmer's usual practice(FUP), Straw compost+chemical fertilizers reduced(SCF), Fresh straw+recommendation(FSC), Fresh cow manure(FCM), Cow manure compost(CMC), and no fertilization as Control(C). And SCF, FCM and CMC were applied with same amounts of total nitrogen to R. The infiltrated water samples were collected in ceramic porous cups which were buried at 60cm depth from the top. Concentrations of nitrate-N in irrigated water were $1.3mg\;l^{-1}$ on rice transplanting season when nutrients began to elute from paddy soil, and $0.4mg\;l^{-1}$ after breaking off irrigation. But it was $4-6mg\;l^{-1}$ in rice growing period. The maximum concentration of nitrate-N in leachate was not more than $7mg\;l^{-1}$ during rice cultivation. The amounts of nitrogen leached in R, FUP, SCF, FSR, FCM, CMC and C were 59, 63, 25, 41, 24, 27, $17kg\;ha^{-1}y^{-1}$ respectively. Nitrogen leaching was decreased to about 30% by supplement of fresh rice straw(FSC) to R. Furthermore, it was possible to reduce to over 50% of nitrogen leaching by reducing chemical fertilizer application(CF), or by substituting of chemical fertilizers with fresh cow manure(FCM) or cow manure compost(CMC). In added organic fertilizer treatments, the amounts of infiltrated nitrogen were less $13-46kg\;ha^{-1}y^{-1}$ than that of input by irrigation. This experiment showed that nutrients leaching was minimized by substitution of chemical fertilizers with organic fertilizer or by application of straw with chemical fertilizers in rice paddy soil and rice cultivation with suitable fertilizer management can work as a purifier rather than contaminator of water.