• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.102-108
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• 2010

The effects of foliar spray of calcium hydroxide ($Ca(OH)_2$) during fruit growth period was investigated by changes of the shoot growth and fruit quality in 'Daewol' peach (Prunus persica). Since foliar spray of $Ca(OH)_2$ 1, 2, 5, and 10 $g{\cdot}L^{-1}$ at 7 day-intervals after fruit thinning, shoot growth was remarkably decreased compared with control group. An average SPAD value of fifth leaf from proximal part of the shoot was higher as 42.1 specific color difference sensor value (SCDSV) of $Ca(OH)_2$ foliar spraying treatments than 40.9 SCDSV of control group. Photosynthesis rates were also significantly increased by treating $Ca(OH)_2$ of higher concentration. Among fruit characteristics affecting quality, fruit weight was increased depending on concentration of $Ca(OH)_2$ treatment. The soluble solids content was lowest in control group (8.78 $^{\circ}Brix$) compare with higher concentrations of $Ca(OH)_2$ foliar spraying treatment in each 9.17, 9.22, 9.71, 10.58 $^{\circ}Brix$. The acidity and anthocyanin contents were no significant differences among treatment, but firmness of pericarp and flesh of fruits was significantly increased by $Ca(OH)_2$ foliar spray treatment. As a results of morphological observation of leaf, thickness of palisade parenchyma was thinner in control group (63.5 ${\mu}m$) than those of each 86.5, 87.5, 93.6, 107.4 ${\mu}m$ in $Ca(OH)_2$ foliar spraying treatment. Higher $Ca(OH)_2$ foliar spray also increased the thickness of cell wall of epidermis and hypodermis in 'Daewol' fruit.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.134-140
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• 2015

We studied to compare with the effect on the shoot growth and yield relavant to weed control methods in peach. As the results about 10 day intervals and 3 times investigation after each primary treatment, treatment plot of 2 times and 3 times with the herbicide, glufosinate ammonium, were 98.2~98.6% into $10^{th}$ day, 78.6~79.6% into $20^{th}$ day, 40.7~41.1% into $30^{th}$ day, fabric covering treatment showed 100%, 100% and 97.5% and treatment plot of machinery weeding were 92.1%, 56.4% and 36.4%, respectively. Also, we compared shoot growth for pre- and post-harvest. In the results, most of weed control methods showed better growth than control. Thus, the average number of standard fruits for treatment plot of 2 times with the herbicide and that of machinery weeding was different significantly in relation to control. Therefore, we think that the herbicide henceforth is well worth the application because treatment of 2 times or 3 times with the herbicide showed significant the control effect against all of 14 weed species surveyed in peach orchard and thus no inhibition for growth and number of standard fruits in peach trees.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.367-372
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• 2001

'Kyoho' grape (Vitis labruscana L.) has currently cropped twice a year in plastic greenhouses. However, there are problems with low fruit quality in the second cropping owing to low temperatures and short photoperiods. This experiment was conducted to investigate the effect of root zone heating and $CO_2$ enrichment in plastic greenhouse on the vine growth and fruit quality of 'Kyoho' grape in double cropping system. The internode length of shoots, leaf area and leaf dry weight at the treatment of soil heating near root zone was significantly different regardless of $CO_2$ enrichment. There were no significant differences in fruit bunch and berry weight, titratable acidity, coloration degree and berry shattering among the treatments, but the soluble solids significantly increased by root zone heating. Photosynthetic rate increased with increasing $CO_2$ concentration from 300 to $800{\mu}mol{\cdot}mol^{-1}$ in sunny day, whereas it didn't increase in cloudy day regardless of $CO_2$ enrichment.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.387-394
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• 2016

Commercial 28 algae removal technologies that have been applied in domestic rivers and lakes with green tide were investigated, analyzed and classified. The classification of algae removal technologies was based on the three criteria (i.e., principle, flow rate of water body, and application period). Also, algae removal technologies were evaluated in terms of cost effectiveness, field applicability, effect durability, and eco friendliness. From the analysis results, technologies using physical, chemical, biological, and convergent controls were 32.2%, 25%, 21.4%, and 21.4%, respectively. The 75% of technologies have been applied to stagnant water body (${\leq}0.2m/s$). Also, algae harvesting ship with dissolved air flotation, conveyor belt and filtration processes and natural floating coagulant were found to have better field applicability, compared to other technologies. However, proper algae removal technology in specific rivers and lakes should be chosen after the evaluation of long-term pilot scale field test. Also, development of energy and resource recovery technologies from algae biomass is warranted.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.235-241
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• 1997

This study was performed to investigate the behaviour of root zone environments under the control of soil temperature and tension of soil moisture near the root Bone of 'Kyoho' grapes tree grown on restricted root zone system in plastic greenhouse. Maximum diurnal air temperature inside plastic greenhouse ranged between 25.1 and 32.7$^{\circ}C$, and the average of nocturnal air temperature inside plastic greenhouse maintained at 18$^{\circ}C$ in winter season. Also the minimum diurnal relative humidity ranged between 50 and 55%, and the maximum nocturnal relative humidity ranged between 84 to 87%. At a depth of 15cm from soil surface, the average soil temperature maintained at 25.6$^{\circ}C$ for under-ground heating, and appeared to 17.4$^{\circ}C$ for unheated condition. Although the tension of soil moisture just after irrigation sharply decreased to pF 1.5, the tension of soil moisture at the depth of 15cm maintained at pF 2.0~2.2. It is suggested that the tension of soil moisture at the depth of 15cm might be used as the standard for the determination of irrigation set point. Effective drainage system is needed to prevent the spindly and succulent growth of vine trees grown in restricted root zone system.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.119-128
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• 2015

The purpose of this study was to look at the Jungeun-sasang(中隱思想) and garden of Bai Juyi in the perspective of landscape architecture and inquiry the meaning of Bai Juyi's construction activities, thought shown in his gardens, and how his construction method influenced later and the result is as follows. First, the 'Jungeun-sasang(中隱思想)' of Bai Juyi improved the Eunil-sasang(隱逸思想) and the birth of 'Jungeun-sasang(中隱思想)' became a clue to be developed up to the garden art. In addition, different from before that built gardens hiding in mountains, it prepared the turning point to build gardens in cities. Second, the space principle of 'paradise' shown in the garden of Bai Juyi was a means and principle to absorb the nature such as positioning rocks, formation of mounds, and positioning of flowers in the limited and small spaces different from previous gardens of splendid and magnificent. The garden became not only outer scene but also the 'Simwon(心園) that reflected the inside world. 12) Third, the gardening act and thought appeared in the poem of Bai Juyi were expressed in pictures and his own gardens as his poem was borrowed and quoted. As a result, Bai Juyi's literary view on the art and thought prepared the base in the popularity of literary gardens and forming of characteristic styles through practical activities that he managed his own gardens. Forth, Bai Juyi's level of Confucianism realization and delicate aesthetical consciousness gave meanings to the scene of gardens through the discovery of the fusion of mountains and creeks, ways of adding, and the aesthetical consciousness of Taihushi(太湖石)and influenced in the forming of garden culture later on.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.1-8
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• 2010

To investigate the effects of sediments on the water quality of an estuary reservoir, Asan reservoir, we analyzed physical and chemical characteristics of the sediments and estimated nutrients release rate from the sediments. The sediments characterized as sandy loam are mainly composed of Nonapatite-P(64.7%) which has strong influence on the eutrophication of the reservoir by releasing from the sediments under the condition of increasing pH and anaerobic environment. High nutrient release rates was observed in April. Negative release rates in June show that there is no significant nutrient release from the sediments. The nutrient release was active at the Site B around the confluence of tributary compared to the Site A near the embankment. Based on the information of nutrient release rates and sediments surface area, daily average nutrient release rates of Asan reservoir are estimated; TN 6,609 kg/d, TP 3,877 kg/d. Since the amount of N and P released from the sediments corresponds to the 7.06% of N and 22.04% of P incoming from the watershed, it can be concluded that there is little influence of sediments on the water quality of Asan reservoir.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.519-526
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• 2017

This study investigated the effect of phosphorus fractionation on the phosphorus release from the sediments of Juksan reservoir in Yeongsan River. The field sediments were collected, incubated, and analyzed with respect to phosphorus fractionation of sediments and total phosphorus (TP) of overlying water after 7 days. The total amount of inorganic phosphorus of YS2 site was higher than YS1 site. Al-P and Fe-P were major constituents of inorganic phosphorus. During the incubation, Al-P, Fe-P and Ca-P were increased and Red-P was decreased at both sites. YS1 site showed increased TP concentration of overlying water, however, YS2 had opposite trend during the incubation. Counting on the particle size distribution of YS1 and YS2, particle size distribution is major factor to control the TP concentration of overlying water. There were positive relationship between Fe-P and TP and negative relationship between Red-P. From the results, it is essential to continuously monitor the sediment phosphorus fraction in order to control the TP concentration of the water.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.111-123
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• 2017

The phycocyanin pigment (PC) is a marker for cyanobacterial presence in eutrophic inland water. Accurate estimation of low PC concentration in turbid inland water is challenging due to the optical complexity and criticalforissuing an early warning of potentialrisks of cyanobacterial bloom to the public. To monitor cyanobacterial bloom in eutrophic inland waters, an approach is proposed to partition non-water absorption coefficient from measured reflectance and to retrieve absorption coefficient of PC with the aim of improving the accuracy in remotely estimated PC, in particular for low concentrations. The proposed inversion model retrieves absorption spectra of PC ($a_{pc}({\lambda})$) with $R^2{\geq}0.8$ for $a_{pc}(620)$. The algorithm achieved more accurate Chl-a and PC estimation with $0.71{\leq}R^2{\leq}0.85$, relative root mean square error (rRMSE) ${\leq}39.4%$ and mean relative error(RE) ${\leq}78.0%$ than the widely used semi-empirical algorithm for the same dataset. In particular, low PC ($PC{\leq}50mg/m^3$) and low PC: Chl-a ratio values of for all datasets used in this study were well predicted by the proposed algorithm.

• Journal of Korea Water Resources Association
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• v.50 no.6
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• pp.373-386
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• 2017

This study simulated water quality item and flow rate of subbasin for Saemangeum watershed using Soil and Water Assessment Tool (SWAT) model and Environmental Fluid Dynamics Code (EFDC) model which simulate hydraulic and water quality in three-dimensions. The simulated values corresponded to observed value well. The result of simulation for floodgate operations at the M3 and M5 points, it exceeds water quality standard and at the M3 and D3 points, change of range for concentration is too wide, and upstream of Saemangeum reservoir is sensitive to inflow flow rate. Compared to the annual average concentration for observed station according to the discharge conditions, improvement of water quality for upstream was apparently compared to the downstream. Range of influence for change of water quality presented that maximum discharge condition, the influence range is 22 km in the direction of the Saemangeum downstream from the Mankyung bridge, and 15 km in the downstream direction of saemangeum in the Dongjin bridge. This study result demonstrated that floodgate operating at upstream has significant influence on water quality management of Saemangeum reservoir and it needs to be considered in plans of water quality management for Floodgate operation on Saemangeum reservoir.