• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.467-471
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• 2009

An attempt was made to provide the most resonable fertilizer recommendation for carrot crop based on soil analytical data and yield response to the NPK fertilizers, which was obtained from field experiments on 2003 in highland, 850 meters above the sea level. Optimum times of N, P, K application to current application methods based on soil test were 0.75-0.50-0.50 for carrot. The adjusted N, P, K recommendation models of highland soil were made by adding the application times to past application methods which were based on chemical properties of soil. The revised models for fertilizer application were recommended to decrease the amount of N-P-K by 25-50-50% for carrot in highland. In application to total cultivation area, 135ha for carrot, saving amounts of NPK fertilizers with these adjusted recommendation in comparison with past application levels will be 23.0 tons for carrot. Using the optimal application amounts for carrot, we will can reduce agricultural pollution without affecting crop yields.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.1-9
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• 2013

This paper presents high-velocity impact analysis of two-way RC slabs, including steel fibers and strengthening with fiber reinforced polymer (FRP) sheets for evaluating impact resistance. The analysis uses the LS-DYNA program, which is advanced in impact analysis. The present analysis was performed similarly to the high-velocity impact tests conducted by VTT, the technical research center of Finland, to verify the analysis results. High-velocity impact loads were applied to $2100{\times}2100{\times}250$ mm size two-way RC slab specimens, using a non-deformable steel projectile of 47.5kg mass and 134.9m/s velocity. In this research, extra impact analysis of material specimens was carried out to verify the material models used to the analysis. The elastic-plastic hydrodynamic model, concrete damage model and orthotropic elastic model were used to simulate the non-linear softening behavior of steel fiber reinforced concrete (SFRC), and material properties of normal concrete and FRP sheets, respectively. It is concluded that the suggested analysis technique has good reliability, and can be effectively applied in evaluating the effectiveness of reinforcing/retrofitting materials and techniques. Also, the Steel fiber and FRP sheet strengthening systems provided outstanding performance under high-velocity impact loads.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1353-1362
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• 2014

In recent years, numerous environmental problems associated with the excessive use of fossil fuel are taking place. For an alternative energy resource, the importance of renewable energy and the demands of facilities to generate renewable energy are continuously rising. To satisfy such demands, a large number of photovoltaic energy generation structures are constructed and planned with large scale. However, because these facility zones are mostly constructed on land, some troubles are occurred such as rising of construction cost due to the cost of land use, environmental devastation, etc. To solve such problems, the floating type photovoltaic energy generation system using FRP members have been developed in Korea. FRP members are recently available in civil engineering applications due to many advantages such as high strength, corrosion resistance, light weight, etc. and they are suitable to fabricate the floating structures because of their material properties. In this study, the analytical and experimental investigations to evaluate the structural performance of floating PV generation structure and SMC FRP vertical member which is used to fabricate the structure were conducted. The static and dynamic performances of floating PV generation structure are evaluated through the FE analysis and the experiment, respectively. Moreover, the structural safety evaluation and buckling analysis of SMC FRP vertical compression member are also conducted by the FE analysis, and the structural behavior of SMC FRP member under compression and pullout is investigated by the experiments. From this study, it was found that the structural system composed of pultruded FRP and SMC FRP members are safe enough to resist externally applied loads.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.85-91
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• 1994

An attempt to adjust the standard levels of NPK fertilizers application was made with the analytical data of soil and the results of field experiments on 18 vegetable crops 1. There was a remarkable accumulation of available $P_2O_5$ and exchangeable K of soil in the periods of 1980~1990 comparing with 1960~1970. 2. New fertilizer recommendations based on the accumulation of soil components enabled to decrease fertilizer requirements of major vegetable crops. It was founded that if such new recommendations were adopted by the farmer, 0~6.0kg N/10a, 0.7~12.3kg $P_2O_5/10a$ and 2.0~9.0kg $K_2O/10a$ could be saved without affecting the yield of crops 3. The formulas of fertilizer application for crops were corrected in order to determine optimal rate of each farmer field according to chemical properties of soil.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.9-16
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• 2016

Buried pipe system is subject to leak or rupture due to internal and external defects with age. Especially, if the pipeline is designed for pressurized gas, the leak can wreak a devastating on its surrounding area. The current method of setting up underground gas pipeline is based on OGP criteria of applying one tenth of the inner pipe pressure. The criteria is applied irrespective of their burial depth or pipe's properties. At times, even the whole safety measures are totally ignored. Considering the magnitude of possible damage from a gas leakage, a precise analytical tool for the risk assessment is urgently needed. The study was conducted to assess possible scenarios of gas accidents and to develop a computer model to minimize the damage. The data from ETA was analyzed intensively, and the model was developed. The model is capable of predicting jet fire influence area with comprehensive input parameters, such as burial depth. The model was calibrated and verified by the historic accident data from Edison Township, New Jersey, the United States. The statistical model was also developed to compare the results of the model in this study and the existing OGP model. They were in good agreement with respect to damage predictions, such as radiation heat coming from 10 meters away from the heat source of gas flame.

• Journal of Life Science
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• v.28 no.8
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• pp.900-907
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• 2018

This study was carried out to evaluate the possibility of unripe apple peel water extracts as cosmetic materials and to evaluate the biological activities of the antioxidant and whitening effects of the samples. The antioxidative properties of the samples were confirmed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) cation radical scavenging ability. To evaluate the whitening effect of the samples, several analytical techniques were used, including toxicity evaluations of the samples by MTT assays. Measurements of the inhibition rates of cellular tyrosinase, melanin synthesis rates, and expression rates of whitening-related proteins and genes were confirmed using melanoma (B16F10 cell). At equivalent unripe apple peel water concentrations ($1,000{\mu}g/ml$), the DPPH radical scavenging and the ABTS cation radical scavenging activities were 77.3% and 93.1%, respectively. The whitening activity evaluation showed that tyrosinase activity and melanin synthesis were inhibited by 19.8% and 17.3%, respectively, at unripe apple peel water extract concentrations of $50{\mu}g/ml$. In B16F10 cells induced by ${\alpha}$-MSH, the expression of tyrosinase, TRP-1, and TRP-2 decreased. Also, the activity of the transcription factor MITF was inhibited. In real-time PCR experiments, the expression of related genes at the upstream signal level was also found to be progressively lowered as the concentration of unripe apple peel water extracts increased. From these results, it was confirmed that the unripe apple peel water extracts showed excellent whitening efficacy and could be used as safe, natural, raw cosmetic material in the future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.29-41
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• 2014

The Korean government has purchased land properties alongside any significant water bodies before setting up the buffers to secure water qualities. Since the annual budgets are limited, however, there has always been the issue of which land parcels ought to be given the priority. Therefore, this study aims to develop efficient mechanism for land acquisition priorities in stream corridors that would ultimately be vegetated for riparian buffer zones. The criteria of land acquisition priority were driven through literary review along with experts' advice. The relative weights of their value and priorities for each criterion were computed using the Analytical Hierarchy Process(AHP) method. Major findings of the study are as follows: 1. The decision-making structural model for land acquisition priority focuses mainly on the reduction of non-point source pollutants(NSPs). This fact is highly associated with natural and physical conditions and land use types of surrounding areas. The criteria were classified into two categories-NSPs runoff areas and potential NSPs runoff areas. 2. Land acquisition priority weights derived for NSPs runoff areas and potential NSPs runoff areas were 0.862 and 0.138, respectively. This implicates that much higher priority should be given to the land parcels with NSPs runoff areas. 3. Weights and priorities of sub-criteria suggested from this study include: proximity to the streams(0.460), land cover(0.189), soil permeability(0.117), topographical slope(0.096), proximity to the roads(0.058), land-use types(0.036), visibility to the streams(0.032), and the land price(0.012). This order of importance suggests, as one can expect, that it is better to purchase land parcels that are adjacent to the streams. 4. A standard scoring system including the criteria and weights for land acquisition priority was developed which would likely to allow expedited decision making and easy quantification for priority evaluation due to the utilization of measurable spatial data. Further studies focusing on both point and non-point pollutants and GIS-based spatial analysis and mapping of land acquisition priority are needed.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.3
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• pp.23-30
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• 2010

Seismic qualification (SQ) is required prior to the installation of safety related electrical cabinets in nuclear power plants (NPPs). Modal identification of the electrical equipment is one of the most significant steps to perform SQ, and is an essential process to construct a realistic analytical model. In this study, shaking table tests were conducted to identify a variation of the dynamic characteristics of a seismic monitoring system cabinet installed in NPPs according to the excitation level. Modal identification of the cabinet has been performed by a frequency domain decomposition method. The results of this study show that the dynamic properties of the cabinet are nonlinearly varied according to the excitation level and the specimen behaves significantly in a nonlinear manner under safe shutdown earthquake motion in Korea. The main sources of the nonlinear behavior of the specimen have been judged by friction forces and geometrical nonlinearity rather than material nonlinearity. The nonlinear variation of the dynamic characteristics of the electrical cabinet might be accepted as an important fact that should be considered during the SQ of safety related equipment.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.415-418
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• 2008

The application of sludge wastes into agricultural fields has been increasing annually in Korea. In particular, sewage sludge application has been widely accepted in decades. Sewage sludge application aid in the recycling of essential nutrients and act as a source of organic matter improving the structure and water-holding properties of the soil. The efficient use of sludge wastes, however, requires an individual assessment of waste products. This study assessed the biological characteristics of organic waste-treated lysimeter soils and develop its indicator to assess the soil health of organic waste-treated lysimeter soils. Several analytical techniques more recently developed such as restriction fragment length polymorphism (RFLP), phospholipid fatty acid (PLFA), and community level substrate utilization (CLSU) fingerprints allow for detailed analyses of soil microbial communities. PLFA and RFLP was, therefore, used in the study to characterize the microbial communities in soil without the need to isolate individual fungi and bacteria. PLFA, RFLP and CLSU have been utilized to assess microbial characteristics of the lysimeter soils with four different sludge wastes for eight consecutive years. Each of these methods was analyzed for a different aspect of soil microbial characteristics. The study would disclose those methods yielded highly reproductive results for each soil and allow distinguishing the soils based on the structures of specific geneand PLFA-pools more than CLSU fingerprints. PLFA methods, especially, revealed the same relative similarities of the treated soils based on cluster analysis of the biological characteristics. Pig manure compost-treated soil, however, was only the same relative resemblance among the three methods. These results indicated that PLFA easily assessed the biological soil characterization.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1620-1620
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• 2001

Forages, both grazed and conserved, provide the basis of ruminant production systems throughout the world. More than 90 per cent of the feed energy consumed by herbivorous animals world - wide were provided by forages. With such world - wide dependence on forages, the economic and nutritional necessity of been able to characterize them in a meaningful way is vital. The characterization of forages for productive animals is becoming important for several reasons. Relative to conventional laboratory procedures, Near Infrared Reflectance Spectroscopy (NIRS) offers advantages of simplicity, speed, reduced chemical waste, and more cost-effective prediction of product functionality. NIR spectroscopy represents a radical departure from conventional analytical methods, in that entire sample of forage is characterized in terms of its absorption properties in the near infrared region, rather than separate subsamples being treated with various chemicals to isolate specific components. This forces the analyst to abandon his/her traditional narrow focus on the sample (one analyte at a time) and to take a broader view of the relationship between components within the sample and between the sample and the population from which it comes. forage is usually analysed by NIRS in dry and ground presentation. Initial success of NIRS analysis of coarse forages suggest a need to better understand the potential for analysis of minimally processed samples. Preparation costs and possible compositional alterations could be reduced by samples presented to the instrument in undried and unground conditions. NIRS has gained widespread acceptance for the analysis of forage quality constituents on dry material, however little attention has been given to the use of NIRS for chemical determinations on undried and unground forages. Relatively few works reported the use of NIRS to determine quality parameters on undried materials, most of them on both grass and corn silage. Only two works have been found on the determination of quality parameters on fresh forages. The objectives of this paper were (1) to evaluate the use of NIRS for determination of nitrogen and moisture on undried and unground forage samples and (2) to explore two mathematical treatments and two NIR regions to predict chemical parameters on fresh forage. Four hundred forage samples (n: 400) were analysed in a NIRS 6500 instrument (NIR Systems, PA, USA) in reflectance mode. Two mathematical treatments were applied: 1,4,4,1 and 2,5,5,2. Predictive equations were developed using modified partial least squares (MPLS) with internal cross - validation. Coefficient of determination in calibration (${R^2}_{CAL}$) and standard error in cross-validation (SECV) for moisture were 0.92 (12.4) and 0.92 (12.4) for 1,4,4,1 and 2,5,5,2 respectively, on g $kg^{-1}$ dry weight. For crude protein NIRS calibration statistics yield a (${R^2}_{CAL}$) and (SECV) of 0.85 (19.8) and 0.85 (19.6) for 1,4,4,1 and 2,5,5,2 respectively, on a dry weight. It was concluded that NIRS is a suitable method to predict moisture and nitrogen on fresh forage without samples preparation.