• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.26-31
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• 1982

The hybrid poplar, populus alba ${\times}$ P.glandulosa $F_1$ shows a strong ability to produce root suckers. The relationship between crown density and root sucker was studied and the other factors that may be related to production of root sucker were also discussed. The possibility was also discussed to use its root suckers for fuelwood forests and vegetation in the area that erosion control is needed.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.469-483
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• 2019

North Korea has experienced floods and sediment-related disasters annually since the 1970s due to deforestation. It is of paramount importance that technologies and trends related to forest restoration and soil erosion control engineering be properly understood in a bid to reduce damage from sediment-related disasters in North Korea, and to effect national territorial management following unification. This paper presents a literature review and bibliometric analysis including 146 related articles published in North Korea. First, we analyzed the textual characteristics of the articles. We then employed the VOSviewer software package to classify the research topic and analyzed this topic based on the time change. The results showed that articles on the topic have consistently increased since the 1990s. In addition, research related to soil erosion control engineering has been classified into four subjects in North Korea: (i) assessment of hazard area on soil erosion and soil loss, sediment related-disasters; (ii) hydraulic and hydrologic understanding of forests; (iii) reasonable construction of soil erosion control structures; and (iv) effects and management plan of soil erosion control works. The proportion of research related to the (ii) hydraulic and hydrologic understanding of forests had been significant during the reign of Kim Ilsung. However, the proportion of research related to the (i) assessment of hazard area on soil erosion and soil loss, sediment-related disasters, increased during the reign of Kim Jongil and Kim Jongun. Using these results, our analysis indicated that an interest in and need for soil erosion control engineering in North Korea has continually increased. The results of this study are expected to serve as a basis for preparing forestry cooperation between North and South Korea, and to serve as essential data for better understanding soil erosion control engineering in North Korea.

• Journal of Forest and Environmental Science
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• v.14 no.1
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• pp.112-127
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• 1998

A meeting for Japan Society of Erosion Control Engineering took place, from May 20-21 in Sapporo, Japan, with the presentations of 21 special topics and 185 general papers. Special topics consists of 6 copies on volcanic disaster prevention, 6 copies on the activity report of Earthquake Erosion Control Engineering Society, 5 copies on the management and guidelines of riparian zone and 4 copies on debris disaster occurred in 1997. General papers consists of 10 copies on slope stability, 10 copies on slope failure, 9 copies on earthquake, 41 copies on environmental erosion control, 25 copies on debris flow, 11 copies on warning and refuge, 10 copies on erosion control plan, 11 copies on erosion control project, 10 copies on erosion control facility, 12 copies on volcanic erosion control, 4 copies on revegetation technology, 4 copies on forest hydrology, 4 copies on avalanche, 4 copies on landslide, 18 copies on debris flow and 2 other copies presented by international student. Among the special topics, 5 papers with the titles of the function and structure of riparian zone, the interactive relation of flood and riparian zone, the management method of channel and river forest for controlling debris flow, the forest restoration efforts by native population, the law and social issue for building river riparian zone were presented in the subsection of "The Management and Guidelines of Riparian Zone". Thus, this article summarize and introduce the presented contents which are very important and can be referred to keep environmentally sound-river in the erosion control field.

• Korean Journal of Materials Research
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• v.27 no.8
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• pp.409-415
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• 2017

For enhanced cavitation erosion resistance of vessel propellers, an electroless Ni-P plating method was introduced to form a coating layer with high hardness on the surface of Cu alloy (CAC703C) used as vessel propeller material. An electroless Ni-P plating reaction generated by Fe atoms in the Cu alloy occurred, forming a uniform amorphous layer with P content of ~10 wt%. The amorphous layer transformed to (Ni3P+Ni) two phase structure after heat treatment. Cavitation erosion tests following the ASTM G-32 standard were carried out to relate the microstructural changes by heat treatment and the cavitation erosion resistance in distilled water and 3.5 wt% NaCl solutions. It was possible to obtain excellent cavitation erosion resistance through careful microstructural control of the coating layer, demonstrating that this electroless Ni-P plating process is a viable coating process for the enhancement of the cavitation erosion resistance of vessel propellers.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.90-96
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• 2013

This study was conducted to investigate a stability trend within 6 above average and 4 blow average erosion control dams, which were selected by The Korean Association of Soil and Water Conservation and were built in 1990s in Gyeonggi and Gangwon Province. The study was aimed to measure rebound hardness of upstream face, flood way and downstream face from those dams selected by using 'Concrete Test Hammer'. The main purposes of the study are selection of compression strength prediction equation and scope of wavelength, which successfully demonstrate non-destructive test results for erosion control dams. There is an opportunity to increase disaster prevention ability when stability vulnerability of concrete erosion control dam is detected in a timely manner. Results of the compression strength investigation express that there is a consistency with visual inspection of stability that has been processed by The Korean Association of Soil and Water Conservation. We concluded that a prediction equation, which was developed by Architectural Institute of Japan (AIJ), shows highest suitability in Korean erosion control dams when stability investigation is performed. The detailed criteria for the test result are 'stable', 'detail inspection required' and 'poor' for over 300 $kgf/cm^2$, 250~300 $kgf/cm^2$ and below 250 $kgf/cm^2$ respectively. Standards for stability of Korean erosion control dam and a compression strength prediction equation (that corresponds to the standards of the stability) should be established on the basis of chronological data of erosion control dam compression strength. Systematical approach for stability inspection that carries out remodeling or repair when problem on erosion control structures are detected through visual inspection and simple stability test, is necessary for the future disaster prevention.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.329-340
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• 2019

Water pollution in erosion control dams is a major issue for forest watershed management, but the effects of erosion control dams on water quality remain poorly understood. In this study, water quality data from streams and dam reservoirs were collected over the Nakdong river basin. Monitored data were further analyzed to examine the relationship between watershed characteristics and water quality. Of the total 43 erosion control dams, less than 10% had lower water quality that was not suitable for agricultural use. TOC and oxygen demand, SS and turbidity, SS and Chl-a, and Chl-a and turbidity showed high correlations (p < 0.01) both in stream water and in detained water. BOD and SS, BOD and Chl-a, BOD and turbidity, and TOC and Chl-a showed high correlations only in stream water. Overall, the results demonstrated that for most erosion control dams the water quality was relatively good. In addition, the quality of downstream water is somewhat affected by the water detained by erosion control dams, in limited ways.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.227-231
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• 2012

Reforestation is one of the most important ways to reduce erosion soil. The objective of this study was to determine the effect of jellyfish soil amendment on seedling growth for reforestation. 100g jellyfish soil amendment was applied into planting hole for the purpose of improvement of the Chamaecyparis obtusa seedling growth. Results showed that during growing period, mortality were 4.4% for the fertilized group and 8.3% for control group. The seedling average height and root diameter were 95.0 cm and 1.07 cm in fertilized group and 40.6 cm and 0.74 cm in control group. The fertilized group was found to be superior (by 1 to 5%) to control group in terms of mortality rate, seedlings height, and root diameter. The positive growth of the fertilized group can be due the increase in soil moisture and the higher availability of nutrients to the plants from jellyfish fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.47-50
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• 2009

Nutrient losses, especially nitrogen and phosphorus, in agricultural runoff can contaminate surface and ground water, leading to eutrophication. Thus, erosion control is crucial to minimizing nutrient losses from agricultural land. Assessments of various erosion control practices were carried out under various cropping system, soil management practices, and slope conditions by means of a lysimeter study and under artificial rainfall. Soil and nutrient losses were monitored in a small agricultural field to evaluate the soil conservation practices. Nutrient losses occur in runoff and leachate (dissolved nutrient) and in sediments (particulate nutrient). Dissolved nitrates accounted for the majority (about 90%) of nitrate transport within the soil. Particulate phosphate in sediments represented the majority (60% to 67%) of phosphate transport. Recently, engineering and agronomic erosion-control practices haver been used to reduce erosion problems in fields on slopes. These practices reduced soil loss, runoff, and nutrient loss to 1/6, 1/2,and 1/3 their original levels, respectively. Bioavailable particulate phosphate in sediments represents a variable but longterm source of phosphate for algae. Dissolved nitrate and phosphate are immediately available for algal uptake, so reducing fluxes of these nutrients should also reduce the risk of eutrophication.

• Journal of Korean society of Dental Hygiene
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• v.17 no.4
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• pp.657-667
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• 2017

Objectives: The aim of this study was to evaluate the potential of dental erosion by three different types of commercial fermented milk on the enamel surface of bovine teeth. Methods: Forty bovine teeth (four groups of 10) were immersed in fermented milk (experimental groups: liquid type, condense-stirred type and condense-drink type) or mineral water (control group) for 1, 3, 5, 10, 15, 30, 60, 90 and 120 minutes. Enamel surface microhardness was measured before and after treatment with a microhardness tester, and Scanning Electron Microscope (SEM) was used to assess the enamel surface morphology. Results:Changes in enamel surface microhardness (before-after treatment; ${\Delta}VHN$) were significantly different among the four groups (p<0.05). ${\Delta}VHN$ was highest in the liquid type group, followed by the condense-stirred type, condense-drink type, and control groups. The ${\Delta}VHNs$ of three types of fermented milk groups were higher than that of the control group (p<0.05). The liquid type group showed higher ${\Delta}VHN$ than the other two types of condense fermented milk groups (p<0.05). However, there was no significant difference in ${\Delta}VHN$ between the two types of condense fermented milk (p>0.05). The results of SEM observation have shown the most severe surface damage in bovine teeth immersed in the liquid type of fermented milk. Conclusions: In this study, it appears that liquid type fermented milk causes greater development of dental erosion. The physical properties and pH of fermented milk types must be considered for prevention of dental erosion associated with ingestion of fermented milk.

• Korean Journal of Environment and Ecology
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• v.34 no.5
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• pp.413-424
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• 2020

Environmental policies and industry practices have recently seen a gradual paradigm shift from reactive management to proactive prevention of environmental impacts. Accordingly, preventive conservation policies are carried out to address the increasing value of protecting soils and soil functions as resources are limited. To propose a direction for future soil erosion research, we analyzed domestic and international research trends of soil erosion, based on journal papers retrieved from the Web of Science databases over the last decade, using VOSviewer for keyword co-occurrence analysis. The results showed that the number of publications on soil erosion per land area in Korea ranked high worldwide. In particular, studies on the soil erosion control were found to account for a more significant proportion than other countries. The active ongoing studies on soil erosion in Korea indicate that the country has recognized the severity of soil erosion resulting from climate, topography, and land use. However, the number of keywords found in the studies on the soil erosion control in Korea was relatively smaller than those found at the international level, indicating the need to diversify and expand the study subjects. In particular, studies on the soil erosion process and the related physical and chemical soil properties are necessary to find the fundamental solutions to soil erosion problems.