• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.238-247
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• 2012

To determine the possibility of solidified se wage sludge for use as a soil cover material in reclaimed land, the growth of energy crops and soil chemical properties investigated in each experimental plots during 2 years (2010 and 2011). The experimental plots consisted of the mixing with solidified sewage sludge plot (SS50), the covering with solidified sewage sludge plot (SS100), and the original reclaimed land plot (ORL) on reclaimed land for the intended landfill in Sudokwon Landfill Site Management Corporation (SLC). Plant height, measured in the second year (2011), was highest in the Geodae 1 grown at plots treated with solidified sewage sludge. The growth of energy crops cultivated in both SS50 and SS100 were better than in ORL. The contents of organic matter (OM) and total nitrogen (T-N) at both SS50 and SS100 were considerably higher than that of the ORL over 2 years. However, the soil from ORL showed higher salinity with high contents of exchangeable $Na^+$ cation than that of SS50 and SS100 over 2 years. We consider that soil chemical and physical properties on reclaimed land used in this study could be improved by the application of solidified sewage sludge due to following reasons. Firstly, the application of solidified sewage sludge may provide soil nutrients on reclaimed land i.e. the growth of energy crops better than in ORL, resulted in more OM and T-N contents in SS50 and SS100. Secondly, the top layers mixed or covered with solidified sewage sludge on reclaimed land may be prevented the salinity accumulation due to capillary rise to surface soil, and improved the cultivation layer for effectively propagating the rhizomes of energy crops. Thus the solidified sewage sludge may be a great soil cover materials for cultivation of bioenergy crops in reclaimed land.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.735-742
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• 2006

The objective of this study was to elucidate the tolerance of woody plants to simulated acid rain in relation to mycorrhizal inoculation. Germinating seedlings of Robinia pseudoacacia were planted in 1I pots with autoclaved soil mixture of vermiculite, sand and nursery soil at 1:1:1 ratio. Each pot was inoculated with both crushed root nodules from a wild tree of the same species and commercial arbuscular mycorrhizal inoculum of Glomus intraradices at the time of planting the seedlings. Simulated acid rains at pH 2.6, 3.6, 4.6, and 5.6 were made by mixing sulfuric acid and nitric acid at 3: 1 ratio. Each pot received nutrient solution without N and P, and was also supplied with 180 ml of the one pH level of the acid rains once a week for 50 days. The plants were grown in the green house. At the end of experimental period, plants were harvested to determine contents of chlorophyll, mineral nutrients and net photosynthesis in the tissues, dry weight of the plants, and mycorrhizal infection in the roots. Mycorrhizal infection rate was significantly reduced only at pH 2.6, which meant vitality of G intraradices was inhibited at extremely low pH. Height growth, dry weight production, nodule production and chlorophyll content were increased by mycorrhizal infection in all the pH levels except pH 3.6. Particularly, mycorrhizal inoculation increased root nodule production by 85% in pH 5.6 and 45% in 4.6 treatments. But the stimulatory effect of mycorrhizal inoculation on nodule production was reduced at pH 3.6 and 2.6. Net photosynthesis was increased by mycorrhizal infection in all the pH levels. The phosphorus(P) content in the tissues was increased by 43% in average by mycorrhizal inoculation, which was statistically significant except in pH 2.6. It was concluded that mycorrhizal inoculation of Robinia pseudoacacia would enhance growth and resistance of the plants to acid rain by improving the photosynthesis, phosphorus nutrition, and more nodule production.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.597-605
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• 2014

The continuous observations for atmospheric aerosols were conducted during 3 years (2009 to 2011) by using Gwangju Institute of Science and Technology (GIST) multi-wavelength Raman lidar at Gwangju, Korea ($35.10^{\circ}N$, $126.53^{\circ}E$). The aerosol depolarization ratios calculated from lidar data were used to identify the Asian dust layer. The optical properties of Asian dust layer were different according to its vertical distribution. In order to investigate the difference between the optical properties of each individual dust layers, the transport pathway and the transport altitude of Asian dust were analyzed by Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. We consider that the variation of optical properties were influenced not only their transport pathway but also their transport height when it passed over anthropogenic pollution source regions in China. The lower particle depolarization ratio values of $0.12{\pm}0.01$, higher lidar ratio of $67{\pm}9sr$ and $68{\pm}9sr$ at 355 nm and 532 nm, respectively, and higher ${\AA}ngstr\ddot{o}m$ exponent of $1.05{\pm}0.57$ which are considered as the optical properties of pollution were found. In contrast with this, the higher particle depolarization ratio values of $0.21{\pm}0.09$, lower lidar ratio of $48{\pm}5sr$ and $46{\pm}4sr$ at 355 nm and 532 nm, respectively, and lower ${\AA}ngstr\ddot{o}m$ exponent of $0.57{\pm}0.24$ which are considered as the optical properties of dust were found. We found that the degree of mixing of anthropogenic pollutant aerosols in mixed Asian dust govern the variation of optical properties of Asian dust and it depends on their altitude when it passed over the polluted regions over China.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.85-94
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• 2009

This study examines the operational effectiveness of a Convection Current Aeration System (CCAS) in reservoir. CCAS was run from June, 2008 when the thermocline begun forming in the reservoir. This paper reviews the influence of stratification, dissolved oxygen dynamics and temperature in the lake's natural state from June to October 2008. The survey was done on a week basis. Upwelling flow effects a radius of $7{\sim}10m$ at a surface directly and was irrelevant to the strength of thermocline. On the other hand, it was affected the number of working days, and strength of thermocline at vertical profiles of the reservoir. Longer CCAS run, the deeper was the vertical direct flow area. However it didn't break the thermocline during summer season of 2008. The operating efficiency of the CCAS in the reservoir depends on hydraulics and meteological conditions. Computational Fluid Dynamics (CFD) is a very useful tool for evaluating the operating efficiency of fluid dynamics. The geometry for CFD simulation consists of a cylindrical vessel 25 m radius and 40 m height. The CCAS is located in center of domain. The non-uniform tetrahedral meshes had a bulk of the geometry. The meshes ranged from the coarse to the very fine. This is attributed to the cold water flowing into the downcomer and rising, creating a horizontal flow to the top of the CCAS. The result of CFD demonstrate a closer agreement with surveyed data for temperature and flow velocity. Theoretical dispersion volume were calculated at 8m depth, 120 m diameter working for 30 days and 10 m depth, 130 m diameter working for 50 days.

• Korean Journal of Dental Materials
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• v.44 no.3
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• pp.273-280
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• 2017

The aim of the present study was to investigate the effects of specimen dimension on the flexural properties and testing reliability of dental composite resin. The composite resin was prepared experimentally by mixing a resin matrix with silanated micrometer glass filler at 50 vol%. Flexural specimens with various dimension in specimen's width were fabricated by light curing using a split metal mold; $25{\times}2{\times}2mm$, $25{\times}2{\times}4mm$, $25{\times}2{\times}6mm$ in length ${\times}$ height ${\times}$ width. The flexural strength and modulus were determined according to ISO 4049 test protocol at a span length of 20 mm (normal-flexural strength; NFS). Another flexural test was conducted using mini-sized specimens ($12{\times}2{\times}2mm$, $12{\times}2{\times}4mm$, $12{\times}2{\times}6mm$) from the broken specimens at a span length of 10 mm (mini-flexural strength; MFS). Data were analyzed with ANOVA and Duncan's post-hoc test and the test reliability was evaluated by Weibull analysis. Results showed that there are generally no significant difference in flexural strength with the increase in the specimen width in NFS and MFS tests. However, the test reliability of flexural strength based on Weibull analysis was largely changed with the variables in the dimension of width and span length. The flexural modulus of NFS was increased as the dimension of specimens width increased while there was no trend in flexural modulus of MFS test. Overall results recommend that the evaluation of flexural properties and the reliability of dental composite resins should be performed with more than one test method.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.858-863
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• 2010

The blueberry farming requires the soil condition of well-drainage, pH of 4.5 to 5.2, and high in organic matters for stable growth and development. Most of soil type of cultivated land in Korea, however, belongs to alkaline soils with low organic matter content and poor drainage. Therefore, the blueberry farmers use peat moss heavily to improve the soil condition, but the guideline on the effective and economic ratio of peat moss is not established yet. This study was performed to determine the cost effective peat moss ratio for amending soils, and to investigate the feasibility of using sawdust and coco peat as soil amendments. Peat moss, coco peat and sawdust are mixed with soil at the ratio of 0, 12.5, 50 and 100% (v/v). Among 3 organic materials with various mixture ratios, the pH of soil was the lowest in 100% peat moss and sawdust mixtures (pH 3.67 and pH 3.73, respectively), followed by pH 5.30 at 50% peat moss. The soil organic matter content are directly proportional to the mixture ratios in all three organic materials and the same trend was observed in the variation of content of exchangeable potassium in the coco peat treatments. On the contrary, the content of available phosphate, exchangeable calcium and magnesium decreased with increasing the ratio of organic materials. The nitrogen content in the leaves decreased as increasing the ratio of peat moss and coco peat in soil, but not of sawdust. The content of phosphate decreased but potassium increased as the ratio of sawdust and coco peat increased. There was no clear difference in the contents of magnesium and calcium among 3 organic materials. The plant height, stem diameter and dry weight of blueberry plants were the highest in 50 % peat moss, followed by 12.5% peat moss and 12.5% coco peat. The plants in 100% peat moss showed very poor growth. It can be concluded that peatmoss, when applied and managed appropriately, will be a good material for improving soil condition as well as securing desirable growth for blueberry. Upon coupling economic aspect, the optimum mixing ratio of peatmoss for blueberry farming is approximately 25-50%.

• Korean Journal of Breeding Science
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• v.42 no.1
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• pp.75-86
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• 2010

End-use properties of 26 Korean wheat cultivars (KWC) were evaluated to assess consumer satisfaction with 6 imported wheat and 5 commercial wheat flours. In end-use quality testing of cooked noodles, Absorption of noodle dough sheet of ASW (Australian standard white) was similar to Anbaek, Eunpa, Gobun, Hanbaek, Jeokjoong, Jonong, Namhae, and Sukang. Thickness of noodle dough sheet of KWC was showed thin difference. In imported wheat and commercial flour, Commercial flour for baking cookie (Com5) with lower protein flour was lower than those flours. In lightness of prepared noodle dough sheet, Lightness value ($L^*$) of KWC was lower than those of Commercial flour for making white salted noodle (Com1), commercial flour for making for yellow alkaline noodle (Com2), and commercial flour for multi-purpose (Com4). Lightness value ($L^*$) showed significantly negative correlations with particle size of flour, ash, damaged starch, and protein content. Hardness of cooked noodles positively correlated with protein content. In texture of cooked noodles, Hardness of Com1 was similar to that of Alchan, Dahong, Jeokjoon, and Sukang. Also, hardness of Com2 was similar to that of Gobun, Jokyung, Jonong, Keumkang, and Namhae. In end-use quality of bread, bread loaf volume of commercial flour for making bread (Com3) was similar to Alchan, Jokyung, Keumkang, and Namhae but firmness was low. Bread volume showed better relationships with higher SDS-sedimentation volume, longer mixing time of mixograph, higher height of dough during development. Firmness of crumb was negatively correlated with bread volume. Diameter of cookie showed significantly negative correlations with particle size of flour, damaged starch, and protein content. Also, Top gain score became higher as the increase diameter of cookie. In end-use quality testing of cooked cookie, Cookie diameter of Com5 was similar to that of Dahong, Geuru, Olgeuru, Tapdong, and Uri but top grain was low.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2013.11a
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• pp.23-24
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• 2013

Micrometeorological fluxes measured over a tall forest in a complex terrain are difficult to interpret. $CO_2$ storage often makes significant contributions to net ecosystem exchange of $CO_2$ (NEE) in early morning and during nighttime due to calm and stable conditions. We measured the above-canopy $CO_2$ flux along with its concentration profiles at eight levels within and above the canopy to evaluate $CO_2$ storage term. Our question is whether or not the $CO_2$ storage term can be estimated accurately from a single level measurement of $CO_2$ concentration in a complex terrain. Our objectives are (1) to document vertical profiles of $CO_2$ concentration and (2) to compare the diurnal and seasonal variations of $CO_2$ storages estimated from single and multi-level $CO_2$ concentration data. Seasonally averaged Diurnal variations of $CO_2$ concentration ranged from 398 to 455 ppm near the forest floor at 0.1 m whereas they ranged from 364 to 395 ppm at 40 m in the atmosphere. The diurnal variation of vertical profiles of $CO_2$ concentration shows very interesting features with season. At all eight levels, diurnal variation of $CO_2$ concentration showed little change in winter. In spring, the diurnal variations of $CO_2$ concentration at 8 levels showed three distinct groups of layers with height: the first layer: 0.1m (near surface), second layer: 1.0 m and 4.0m (below canopy) and the third layer: 7.4m to 40.7 m (near canopy and above). In summer, these three groups of layers were further separated with larger variations whereas such distinction became smaller in fall. The diurnal variation of $CO_2$ concentration in the first three layers near surface always showed higher concentration with larger variability. Typically, $CO_2$ concentration showed peaks in early morning and in the evening. After the evening peak, $CO_2$ concentration gradually increased except for those near the surface (i.e., 0.1, 1.0 and 4.0 m) where the concentrations actually decreased. We suspect that this could be attributed to the drainage flow of $CO_2$ along the hill slope from the headwater to downstream, which is not taken into account for net ecosystem $CO_2$ exchange. In comparison to the results of other studies, the distinct and different vertical structures of $CO_2$ concentrations observed at our site may be due to complex terrain and weak turbulent mixing under calm conditions at the site. The annual mean of diurnal variation of $CO_2$ storage flux from single level ranged from -0.6 to $0.9{\mu}mol\;m^{-2}s^{-1}$ and from multi-level from -1.2 to $1.0{\mu}\;{\mu}mol\;m^{-2}s^{-1}$. When compared against the results from the multi-level concentrations, the storage flux estimated from a single-level concentration was generally adequate except for specific hours near sunrise and sunset. Further details and their implication will be discussed in the presentation.

• Journal of the Korean Orthopaedic Association
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• v.54 no.5
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• pp.435-439
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• 2019

Purpose: This study evaluated the efficacy of blood mixed cement for osteoporotic vertebral compression fractures in reducing the complications of percutaneous vertebroplasty using conventional cement. Materials and Methods: This study was performed retrospectively in 80 patients, from January 2016 to January 2017. Porous cement was formed by mixing 2, 4, and 6 ml of blood with 20 g of cement used previously. A tube with a diameter and length of 2.8 mm and 215 mm, respectively, was used and the polymerization temperature, setting time, and optimal passing-time were measured and compared with those using only conventional cement. Radiologically, the results were evaluated and compared. Results: The polymerization temperature was 70.3℃, 55.3℃, 52.7℃, and 45.5℃ in the conventional cement (R), 2 ml (B2), 4 ml (B4), and 6 ml (B6), respectively, and the corresponding setting time decreased from 960 seconds (R) to 558 seconds (B2), 533 seconds (B4), and 500 seconds (B6). The optimal passing-time was 45 seconds (B2), 60 seconds (B4), and 78 seconds (B6) at 73 seconds (R), respectively and as the amount of blood increased, it was similar to the cement passing-time. The radiological results showed that the height restoration rates and the vertebral subsidence rates similar among the groups. Two cases of adjacent vertebral compression fractures in the R group and one in the B2 and B4 groups were encountered, and the leakage rate of the cement was approximately two times higher than that in the conventional cement group. Conclusion: In conventional percutaneous vertebroplasty, the procedure of using autologous blood with cement decreased the polymerization temperature, reduced the setting time, and the incidence of cement leakage was low. These properties may contribute to more favorable mechanical properties that can reduce the complications compared to conventional cements alone.

• Korean Journal of Heritage: History & Science
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• v.45 no.4
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• pp.140-157
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• 2012

The result of a study on the useful trend of plants related to landscape and how to plant and cultivate through 'ImwonGyeongjaeji Manhakji'of Seoyugu is as follows: First, 'ImwonGyeongjaiji Manhakji', composed of total 5 volumes (General, Fruit trees, vegetables and creeper, plants, others) is a representative literature related to landscape which described the names of plants and varieties, soil condition, how to plant and cultivate, graft, how to prevent the insect attack etc systematically. Second, he recorded the tree planting as Jongjae(種栽) or Jaesik(栽植), and the period to plant the trees as Jaesusihoo(栽樹時候), transplanting as Yijae(移栽), making the fence as Jakwonri(作園籬), the names of varietieis as Myeongpoom(名品), the suitable soil as Toeui(土宜), planting and cultivation as Jongye(種藝), treatment as Euichi(醫治), protection and breeding as Hoyang(護養), garden as Jeongwon(庭園) or Wonpo(園圃), garden manager as Poja(圃者) or Wonjeong(園丁). Third, the appearance frequency of plants was analyzed in the order of flowers, fruits, trees, and creepers and it showed that the gravity of deciduous trees was 3.7 times higher than that of evergreen trees. The preference of flower and trees, fruit trees and deciduous trees and broad-leaved trees includes (1) application of the species of naturally growing trees which are harmonized with the natural environment (2) Aesthetic value which enables to enjoy the beauty of season, (3) the trend of public welfare to take the flowers and fruits, (4) the use of symbolic elements based on the value reference of Neo-Confucianism etc. Fourth, he suggested the optimal planting period as January(上時) and emphasized to transplant by adding lots of fertile soil and cover up the seeds with soil as high as they are buried in accordance with the growing direction and protect them with a support. That is, considering the fact that he described the optimal planting period as January by lunar calendar, this suggests the hints in judging the planting period today. For planting the seeds, he recommended the depth with 1 chi(寸 : approx. 3.3cm), and for planting a cutting, he recommended to plant the finger-thick branch with depth 5 chi(approx. 16.5cm) between January and February. In case of graft of fruit trees, he described that if used the branch stretched to the south, you would get a lot of fruit and if cut the branches in January, the fruits would be appetizing and bigger. Fifth, the hedge(fence tree) is made by seeding the Jujube tree(Zizyphus jujuba var. inermis) in autumn densely and transplanting the jujube tree with 1 ja(尺 : approx. 30cm) interval in a row in next autumn and then binding them with the height of 7 ja(approx. 210cm) in the spring of next year. If planted by mixing a Elm tree(Ulmus davidiana var. japonica) and a Willow(Salix koreensis), the hedge whose branch and leaves are unique and beautiful like a grating can be made. For the hedge(fence tree), he recommended Trifoliolate orange(Poncitus trifoliata), Rose of sharon(Hibiscus syriacus), Willow(Salix koreensis), Spindle tree(Euonymus japonica), Cherry tree(Prunus tomentosa), Acanthopanax tree(Acanthopanax sessiliflorus), Japanese apricot tree(Prunus mume), Chinese wolf berry(Lycium chinense), Cornelian tree(Cornus officinalis), Gardenia(Gardenia jasminoides for. Grandiflora), Mulberry(Morus alba), Wild rosebush(Rosa multiflora) etc.