• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.223-235
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• 2006

Soil testing laboratories unfamiliar with turfgrasses will often overestimate the plant's need for phosphorus and underestimate the need for potassium. This is partly due to differences in rooting between grasses and many garden plants and crops. The grasses are generally more efficient in extracting phosphorus from the soil, reducing their need for phosphorus fertilizer. The fact that crop yield is often the primary objective in field crop production, and is usually of little interest in turfgrass management, may affect soil test interpretation for potassium. Potassium levels above those required for maximum tissue yield of grasses may improve stress tolerance and turfgrasses will usually benefit from higher applications of this element. There are also diffrrences in soil testing philosophies. Some laboratories use the sufficiency level of available nutrients(SLAN) approach, whereas others prefer the basic cation saturation ratio(BCSR) approach. Some will use a combination of the two methods. The use of the BCSR theory easily lends itself to abuse and questionable fertilizer applications and products are sometimes recommended citing imbalances in cation ratios. The usefulness of the BCSR ratio theory of soil testing varies with soil texture and interpretations on tests performed on sand-based media are particularly a problem. Other soil testing problems occur when sand-based media used on sports fields and golf greens contain free calcium carbonate. The ammonium acetate extractant at pH 7.0 dissolves excessive amounts of calcium that can bias cation exchange capacity measurements and measurements of cation ratios. Adjusting the pH of the extractant to 8.1 can improve the accuracy of the testing procedure for calcareous media.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1047-1050
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• 2010

This study was to investigate the effects of rice straw incorporation by cutting height on paddy soil fertility. The average residual amount of rice straw by cutting height were showed 1,420 kg $ha^{-1}$, 1,850 kg $ha^{-1}$, and 2,400 kg $ha^{-1}$ for depths of 10 cm, 15 cm, and 20 cm, respectively. For soil physical properties, soil hardness and bulk density were decreased while porosity was increased by rice straw incorporation. But soil organic matter (SOM), available silicate content, and cation exchange capacity (CEC) were significantly decreased when rice straw was removed from the field. These results indicated that the SOM as residual amount of rice straw was influenced by level of cutting height. Milled rice yield was increased by 28% and 32% for cutting heights of 15 cm and 20 cm, compared with that of control, respectively. The number of spikelets per square meter and the percentage of ripeness were increased with increasing incorporation by lower level of cutting height of rice straw. Therefore, incorporation of rice straw practices under cutting method influenced soil improvement and rice yield in paddy field.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.392-399
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• 2007

This study was carried out to assess optimum conditions of peatmoss-based substrates for red pepper plug seedlings. Peatmoss-based substrates prepared by mixing of peatmoss with vermiculite, perlite, rice hull and zeolite at various mixing ratios were used for growing pepper plug seedlings. The physical and chemical properties of the peatmoss substrate were analyzed by the CEN(European committee for standardization) method. Fresh and dry weights (shoot, root), leaf area, root length and T/R ratio (dry shoot weight/dry root weight) were determined at 55 days after sowing. The results showed that the growing media PVSZ 6 (peatmoss:silver vermiculite: zeolite=6:3.9:0.1) and PVGZ 6 (peatmoss:gold vermiculite: zeolite=6:3.9:0.1) can successfully be used for red pepper plug seedlings judging from dry weight and T/R ratio of the plug seedlings. The optimal ranges of total pore space, water volume, air volume, easily available water content and water buffering capacity of the peatmoss based growing media for pepper plug seedlings were 87~93%, 52~71%, 20~41%, 10~37% and 0.6~10%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.369-376
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• 2007

This experiment was carried out to investigate optimum conditions of coir-based substrates for the red pepper plug seedlings. Eleven different coir based substrates prepared by mixing of coir, vermiculite, rice hull, perlite, zeolite, mixed at different ratios were tested. The physical and chemical properties of the substrates were analyzed by the CEN (European committee for standardization) method. Fresh and dry weights of shoot and root, leaf area, root length, and T/R ratio (dry shoot weight/dry root weight) were determined at 55 days after sowing. The results showed that the growing media CRZ 8(coir:rice hull: vermiculite=8:1.9:0.1) and CVSZ 6(coir:silver vermiculite: zeolite=6:3.9:0.1) can successfully be used for pepper plug seedlings judging from dry weight and T/R ratio of the plug seedlings. The optimal range of total pore space, water volume, air volume, easily available water content and water buffering capacity of the coir-based growing substrates for pepper plug seedlings were in the range of 92~94%, 52~60%, 32~43%, 18~21%, and 0.9~8%, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.867-874
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• 2021

The IoT (Internet of Things) technology is rapidly becoming an important consideration in many engineering fields in the current 4th industrial era. In recent years, the concepts of digital shipbuilding and smart factories have been adopted as trends in shipyards. However, there is active interest in research on implementing autonomous driving in autonomous vehicles and airplanes, which is currently available in commercial form in a limited capacity. The present study is regarding the path-tracking performance of a boat to accomplish an autonomous driving mission using a flight controller (FC) and real-time kinematic (RTK) global positioning system (GPS) based on an open-source Ardupilot; an actual sea test is also performed using this system on a calm lake. The boat's mission is to evaluate the maneuverability of the self-driving process to a specific point and returning to the home position. For a given speed, the difference between the preset mission trajectory and actual operational trajectory was analyzed, and a series of studies were conducted on the applicability of the system to ships. In addition, the movements and maneuverability of the OmniX-type hull with four propellers were investigated, and the driving path-tracking performance was observed to increase by a maximum of 48%.

• Molecules and Cells
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• v.44 no.10
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• pp.770-779
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• 2021

Transgenic Arabidopsis thaliana expressing an anti-rabies monoclonal antibody (mAb), SO57, was obtained using Agrobacterium-mediated floral dip transformation. The endoplasmic reticulum (ER) retention signal Lys-Asp-Glu-Leu (KDEL) was tagged to the C-terminus of the anti-rabies mAb heavy chain to localize the mAb to the ER and enhance its accumulation. When the inaccurately folded proteins accumulated in the ER exceed its storage capacity, it results in stress that can affect plant development and growth. We generated T₁ transformants and obtained homozygous T₃ seeds from transgenic Arabidopsis to investigate the effect of KDEL on plant growth. The germination rate did not significantly differ between plants expressing mAb SO57 without KDEL (SO plant) and mAb SO57 with KDEL (SOK plant). The primary roots of SOK agar media grown plants were slightly shorter than those of SO plants. Transcriptomic analysis showed that expression of all 11 ER stress-related genes were not significantly changed in SOK plants relative to SO plants. SOK plants showed approximately three-fold higher mAb expression levels than those of SO plants. Consequently, the purified mAb amount per unit of SOK plant biomass was approximately three times higher than that of SO plants. A neutralization assay revealed that both plants exhibited efficient rapid fluorescent focus inhibition test values against the rabies virus relative to commercially available human rabies immunoglobulins. KDEL did not upregulate ER stress-related genes; therefore, the enhanced production of the mAb did not affect plant growth. Thus, KDEL fusion is recommended for enhancing mAb production in plant systems.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.187-194
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• 2021

This study aimed to optimize the preparation method of citron (Citrus junos Sieb.) beverages with hibiscus using response surface methodology (RSM). The experimental conditions were established using a central composite design with three independent variables as follows: ratios of citron (40~60%), citric acid (0.34~0.94%), and hibiscus (0.3~0.7%). The results indicate that an increase in the citron ratio contributed to increased sweetness and as the concentration of citron and hibiscus increased, the brightness of the citron beverage decreased and the yellowness increased. The citron ratio showed a significant correlation with the ABTS radical scavenging capacity. Among the 15 experimental groups, 4 representative samples showing statistical significance were selected, and sensory tests were performed, in comparison with commercially available products. As a result of the sensory test, four beverages prepared with the selected recipes showed higher preference than commercial beverages, and optimal recipe conditions were 40% citron, 0.34% citric acid, and 0.5% hibiscus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.230-236
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• 2018

Earthquakes over 5.0 on the Richter scale have recently occurred in Korea, which has led to interest in the seismic safety of structures. If a water storage facility is damaged by an earthquake, the water could leak, and the insufficient water would make fire suppression difficult. Therefore, a water storage facility should satisfy safety requirements for earthquakes. In this study, the seismic performance of a water tank was improved by installing a lead rubber bearing between the foundation and the tank. It designed the lead rubber bearing available to the existed concrete foundation. ANSYS was used for modeling to consider the interaction between the fluid and structure of the tank and the hydrostatic and hydrodynamic pressure using four seismic waves. In the case of hydrostatic pressure at 2.5 water level, full level, the same stress appeared irrespective of whether the seismic isolation was installed. When hydrostatic pressure and hydrodynamic pressures are applied at the same time, the seismic-isolated water tank showed less seismic force, and the damping ratio was lower than that of general seismic isolation. This occurred because the weight of the water tank is much smaller than the stiffness of the seismic isolation. The result is expected to be used for further research on seismic capacity evaluation for water tanks.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.123-128
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• 2018

MDF was treated on the surface of MDF with fire retardant lacquer, water-soluble flame retardant coat and water-soluble wood cover on the MDF wood, and the pyrolysis characteristics and the atmospheric noxious gas generation characteristics were investigated by using the large capacity thermal analyzer. As a result of investigating pyrolysis and combustion gas generation characteristics after treatment of 0.11 / 11.55 g in terms of mass ratio, it was found that combustion starting time was slightly longer than that of pure MDF in the case of treatment with fire retardant lacquer. The combustion temperature was increased from $340^{\circ}C$ to $450^{\circ}C$. The pyrolysis and combustion gas generation characteristics of the MDF wood treated with the aqueous flame retardant coat showed the changes in combustion starting time and temperature from $260^{\circ}C$ to $542^{\circ}C$ for about 26 minutes at the mass ratio of 0.13 / 11g. Also, when the commercially available waterproof wood cover was treated with 0.13 / 11.55 g of MDF, the sudden weight change tended to increase from $300^{\circ}C$ to $370^{\circ}C$ and showed a second change at approximately $500^{\circ}C$.

• Journal of Korea Water Resources Association
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• v.52 no.4
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• pp.235-243
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• 2019

Recently, urban inundation was frequently occurred due to the intensive rainfall exceeding marginal capacity of the flood control facility. Furthermore, needs for the underground storage facilities to mitigate urban flood are increasing according to rapidly accelerating urbanization. Thus, in this study, drainage efficiency in drain tunnel connecting to underground storage was investigated from the air-core measurements in the drop shaft against two types of inlet structure. In case of the spiral inlet, the multi-stage structure is introduced at the bottom of the inlet to improve the vortex induction effect at low inflow discharge (multi-stage spiral inlet). The average cross-sectional area of the air-core in the multi-stage spiral inlet is 10% larger than the tangential inlet, and show the highly air emission effect and the highly inflow efficiency at the high inflow discharge. In case of the tangential inlets, the air emission effect decreased after exceeding the maximum inflow discharge, which is required to maintain the inherent performance of the tangential inlet. From the measurements, the empirical formula for the cross-sectional area of the air-core according to locations inside the drop shaft was proposed in order to provide the experimental data available for the inlet model used in experiments.