• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.57-61
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• 1992

For testing salts effect on seed germination, nitrogen solutions($(NH_4)_2SO_4$, $NH_4NO_3$, $KNO_3$, $Mg(NO_3)_2$, $Ca(NO_3)_2$, $(NH_2)_2CO$) were treated to chinese cabbage(Brassica rape L.) and lettuce(Lactuca sativa L.) seeding on the quartz sand bed given a tilt to wet by dripping. Electrical conductivities (mS/cm) increased with direct proportion by equivalent gram-molecular weight at $(NH_4)_2SO_4$ and $KNO_3$, $NH_4NO_3$, but those of Mg and Ca salt remained 1 1/2 times higher. And urea solution never showed EC at all. $(NH_4)_2SO_4$ solution appeared to have value of EC with 1.37 times as high as that of $KNO_3$ and it was in order of $(NH_4)_2SO_4>NH_4NO_3>KNO_3>Ca(NO_3)_2>Mg(NO_3)_2$ comparing with same percentage solution. Application of $Mg(NO_3)_2$ and $(NH_4)_2SO_4$ among 6 salts resulted in a severe decreas in germination of both crops, and $NH_4NO_3$ showed light inhibition in comparison to $KNO_3$. Urea showed little effect on germination as the same as $Ca(NO_3)_2$ and $KNO_3$ solution at low concentrations, but the latter two salts reduced germination remarkably at high concentrations. It is likely to show that germination inhibition is not affected by salt salanity but by the sort of salts.

• Journal of the Korean Arthroscopy Society
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• v.9 no.1
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• pp.40-45
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• 2005

Purpose: This study is to evaluate the clinical findings of media] meniscus root tear, pull-out repair technique and it's short term results. Materials and Methods: From September 2003 to August 2004, 23 cases of total 27 medial meniscus root tears were treated by pull-out repair technique. Mean age was 60.2 years old. The pull-out technique was divided into 2 groups In group 1(14/23 cases), anterolateral portal was used and in group 2(9/23 cases), anterolateral and posteromedial portals were used for bed preparation. Concomitant cartilage lesions were documented as ICRS mapping system. The clinical outcomes were evaluated according to Lysholm Knee Score. Results: The postoperative Lysholm Knee Score was 77.1(range; $58{\sim}97$) in group 1 and 81.4(range; $72{\sim}94$) (p>0.05). The failure rate was 3 of 14 cases(21.4%) in group 1 and 1 of 9 cases(11.1%) in group 2. Twenty of 22 cases(90.9%) showed cartilage lesions in weight bearing portion of medial femoral condyle which were 8 grade III and 5 grade IV according to the Outerbridge classification. Conclusion: Pull-out repair seems to be a useful treatment of the medial meniscus root tear for preservation of circumferential hoop tension of meniscus.

• Explosives and Blasting
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• v.18 no.2
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• pp.7-13
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• 2000

Abstract The characteristics of bed rock in the study area was classified by means of the crack coefficient estimated from the seismic velocities of in-situ and intact rocks. Various statistical methods were investigated in order to minimize the possible errors in estimating the predictive equation of blasting vibration and to enhance the determination coefficient $R^2$, for more reliable estimation. The determination coefficient showed the highest in the analysis for those groups using weighting function with the number of samples. The analysis for the weighting function employed with standard coefficient and variance also enhanced the determination coefficients significantly compared to the others, but the reliability was slightly lower than results obtained former method. Therefore the most reliable predictive equation of blasting vibration was found to be obtained from a regression analysis of the mean vibration level using the weighting of same distance groups within 15m with the same explosive charge weight per delay. The coefficients, K and n 317.4 and -1.66, respectively, when using the square root scaling, and 209.9 and -1.66, respectively, when using the cube root scaling. The analysis also showed that the square root scaling may be used in the distance less than 31m form the blast source, and the cube root scaling in the distance more than 31m for safe design.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.535-541
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• 1996

A seed pelleting technique was developed for easy handling of small tobacco seeds (variety, NC82) and for direct seeding in temperary planting bed or in field. The mixture of pelleting material, binder and seeds were moulded in cylindrical holes sized 2 mm diameter and 2 mm height in a plastic plate. Bentonite and cellulose powder were good materials to make pellets with CMC as binder, and bentonite formed the hardest pelleted seeds among the materials. The number of the pelleted seeds made with the same weight of the materials was different with materials used and the number of seeds contained in a pelleted seed could be controlled by mixture ratio of materials and seeds. The seedless pellets ranged 6.9 to 16.0% at the ratio of pelleting material and seed for 2~3 seeds in a pellet. The moisture absorption rate at 100% RH and $25^{\circ}C$ was greater in the order of clay < bentonite < cellulose. Germination rates of pelleted seeds with bentonite and cellulose were similar to that of usual seed, but it was significantly lower with clay pelleted seeds.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.1-6
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• 2012

Down Stream K River has high COD (4-10 mg/L) and high $NH_3$-N concentration (3.5 mg/L during winter period). Although $NH_3$-N itself is not reported harmful at this level, it must be removed to meet drinking water standard (0.5 mg/L). We constructed a pilot plant modifying the processes of conventional drinking water facilities. Prechlorination and powdered activated carbon (PAC) dechlorination was adopted prior to a flocculation tank to remove ammonia and prevent disinfection byproducts (DBPs) formation. Also, GAC processes was included after sand filter to remove residual DOC. This pilot having a capacity of 36 ton/day was operated for one year. The GAC processes were successful to remove ammonia and many organic pollutants (DOC, MBAS, UV-254 nm absorbance, etc). Influent DOC concentrations were very high as 3~6 mg/L throughout the plant operation. It was impossible to achieve 1.0 mg/L effluent DOC, indicating that bed depth (2 m) should be increased to achieve more strict DOC quality standards. When $Cl_2$ dose was well controlled ($Cl_2/NH_3$-N ratio 10~11 on a weight basis), $NH_3$-N removal was 98% and THMs was very low possibly due to low free residual chlorine and PAC dechlorination.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.414-418
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• 2011

BACKGROUND: Plastic mulches widely used in raised-bed culture mainly to conserve water, control weeds and raise soil temperature. The most widely used plastic mulch colour is black. Reflective red and far-red light can affect on growth and yield of various vegetable crops. Objectives of this study were to investigate the characteristics of reflective light of black and red plastic mulches, and to evaluate the reflective red and far-red light on the quality characteristics and yield of the Oriental melon (Cucumis. Melo L.) and tomato (Lycopersicon esculentum L.). METHODS AND RESULTS: Oriental melon and tomato were cultivated over the reflective red and black plastic mulches in plastic house. Reflected red and far-red light over the red plastic mulch were 2.6 times higher than those of black plastic mulch. Red to F-Red ratio of black plastic mulch, red plastic mulch and sunlight were 1.14, 0.93 and 1.16 respectively. Intensity of reflected red and far-red light over red plastic mulch were highest at surface height of 30 cm. The higher the height of the surface decrease the intensity of far-red light. Accordingly, Red to F-Red ratio were increased. Reflective red plastic mulch increased the weight of fruit and content of sugar in Oriental melon and tomato. CONCLUSION(s): Yield of Oriental melon over reflective red plastic mulch was higher than that of black plastic mulch. These results suggested that reflected red and far-red light over the red plastic mulch affected allocation of photosynthate in growing Oriental melon.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.305-312
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• 2007

Among many types of light rail transits (LRT), the rubber-tired automated guide-way transit (AGT) is prevalent in many countries due to its advantages such as good acceleration/deceleration performance, high climb capacity, and reduction of noise and vibration. However, AGT is generally powered by high-voltage electric power feeding system and it may cause electromagnetic interference (EMI) to measurement sensors. The fiber optic sensor system is free from EMI and has been successfully applied in many applications of civil engineering. Especially, fiber Bragg grating (FBG) sensors are the most widely used because of their excellent multiplexing capabilities. This paper investigates a prestressed concrete girder bridge in the Korean AGT test track using FBG based sensors to monitor the dynamic response at various vehicle speeds. The serviceability requirements provided in the specification are also compared against the measured results. The results show that the measured data from FBG based sensors are free from EMI though electric sensors are not, especially in the case of electric strain gauge. It is expected that the FBG sensing system can be effectively applied to the LRT railway bridges that suffered from EMI.

• Resources Recycling
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• v.29 no.1
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• pp.53-61
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• 2020

This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.765-776
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• 2019

The purpose of this study is to provide the legal and institutional guidelines and standards that can be used in the whole river restoration project and to analyze and evaluate the performance of the river project. We constructed an assessment system of four biological taxa that can represent the river environments, namely, evaluation indexes and standards of vegetation and birds, benthic invertebrates and fishes. Specifically, the assessment indicator and criteria of biological characteristics are summarized, so that in case of vegetation community, vegetation diversity, vegetation complexity, and vegetation naturalness can be quantitatively assessed through the combination of three indices. Based on the scientific basis of the advanced techniques, benthic invertebrates, fishes, and birds were proposed to quantitatively evaluate assessment grades according to the classification of biological data. In order to evaluate biological characteristics, which are a part of river environmental naturalness, we proposed a comprehensive biological index and evaluation grade applying the weight of these four biological taxa, and it clearly reflects the characteristics of river environment in test bed.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.3
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• pp.274-279
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• 1983

In order to find out the application effect of commercial organic fertilizer on the germination rate of ginseng seed, growth of ginseng plant and changes of the physicochemical properties of soils, a Miwon organic fertilizer, byproduct of amino acid fermentation, was applied to the ginseng nursery bed. The application rates of Miwon organic fertilizer were 0kg-N from organic fertilizer and 30kg-N from wild grass compost per 10a as control(namely 0kg-N/10a), 2.5kg-N and 27.5kg-N/ 10a(2.5kg-N/10a) 5.0kg-N and 25kg-N/10a(5.0kg-N/10a), 10kg-N and 20kg-N/10a(10kg-N/10a), 15kg-N and 15kg-N/10a(15kg-N/10a) respectively, The obtained results are as follows: 1. The germination rate of ginseng seed were better in the plots that received 2.5kg, 5.0kg and 10kg-N/10a as compared with control plot. However no difference was found on germination rate between control and 15kg-N/10a, 2. The higher rate of missing plant was found in the 15kg-N/10a plot that showed poor growth. However control and 10kg-N/10a plot showed similar rate of missing plant. The best result, lower rate of missing plant, was obtained in the order of 5kg-N and 2.5kg-N/10a respectively. 3. The significant heavier ginseng root weight was obtained in 5kg-N/10a and 10kg-N/10a plot. However the root weight was decreased in the order of 2.5kg-N/10a, control, 15kg-N/10a. 4. In the physicochemical changes of soils between control and organic fertilizer treated soil before and after harvesting the increment of pH, C.E.C. and organic matter content along with the rate of organic fertilizer application were found. There were significant correlation between nitrate nitrogen and the rate of organic fertilizer application. 5. In the view points of germination rate, missing rate of plant and yield of ginseng root, it can be stated that the best result could be obtained from the plot that received 10kg-N/10a from Miwon commercial organic fertilizer and 10kg-N/10a from wild grass compost.