• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.10
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• pp.67-73
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• 2010

In this paper, the effect of a finite substrate on the mutual coupling of a pair of microstrip patch antennas along the H -plane is investigated. The mutual coupling of a pair of microstrip patch antennas can be reduced using the interference effect due to the phase difference by a variety of routes of the surface wave. In the case of the substrate with $\varepsilon_r$=10 and thickness of 3.2 mm, the mutual coupling is reduced by 4.85 dB on the substrate size with the strong mutual coupling, while the mutual coupling is reduced by 34.28 dB on the substrate size with the weak mutual coupling when the distance between the antenna centers is varied from 0.5 $\lambda_0$ to 1.0 $\lambda_0$. In the case of optimization substrate size, the decreasing rate of the mutual coupling with the increase of the distance between the antenna centers is very large. Good agreements between the image method and full wave simulation results are obtained.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.3
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• pp.21-32
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• 2009

Coastal sand dune area is the important ecosystem as an ecotone which located between coastal area and terrestrial area. Moreover, it is very complicate landscape that have geomorphological interaction between erosion and accumulation of sand. Therefore, it is necessary to understand the sand dune ecosystem in view point of landscape scale including background landscape affecting origin of sand dune. Landscape ecological approach in the complicate ecosystem already started in developed countries, and it is applied to land management and biodiversity conservation strategies even in national scale. In this paper, landscape ecological analysis using landscape pattern analysis was carried out on 7 study areas (Yellow Sea : Hakampo and Doksan, South Sea : Namyeol and Balpo, East Sea : Hosan, Hupo and Goraebul) in Korean coastal sand dune ecosystem. Landscape elements were composed by 9 elements in these study areas. Major background landscape elements was the forest land and agricultural field. Namyeol (S06) has larger patch landscape compare to other areas. In patch shape indices, Hupo (E10) shows more complicate patch shapes. The high landscape heterogeneity showed in the Doksan sand dune area and that of Hosan. It shows that these areas were composed by various patch types. However, using landscape indices have to use very carefully because several variables have influence to the result such as scale and spatial pattern of study areas. Although landscape analysis through landscape indices shows sometimes difficult to explain the ecosystem, landscape scale approach on ecosystem assessment still useful to interpret in ecological process in large range of habitat.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.587-594
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• 2019

This study experimentally investigated the effects of high and low densities of vegetation patches on the flow characteristics in a stream-scale outdoor experimental channel with rooted willows. Stream-scale experiments on vegetated flows were carried out for an emergent condition of vegetation. Vegetation patches were arranged by alternate bar formation and the flows in vegetated and non-vegetated sections were compared. Three-dimensional flow structure was measured by ADV (Acoustic Doppler Velocimeter) and the vertical distributions of longitudinal velocity were mainly analyzed from the measurements at various points. Flow velocities show different patterns depending on the density of vegetation patches. The difference in flow velocity between in the vegetated and non-vegetated sections appear to large in the dense patches and the flow becomes complicated at the downstream edge of the patch. Despite the upstream flow disturbed by the first patch, the flows over the second patch show the similar pattern.

• Journal of Chest Surgery
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• v.24 no.2
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• pp.123-134
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• 1991

Twenty eight patients had undergone repair of an isolated complete atrioventricular septal defect between April 1986 and September 1990 in Seoul National University Children`s Hospital. The group comprised 13 male and 15 female patients. They ranged in age from 2 months to 8 years[mean 18.6months] and in weight from 3. 4kg to 23kg[mean 9.0$\pm$4.6kg]. They were analysed as Rastelli type A in 17 patients, Rastelli type B in 2 patients, and Rastelli type C in 9 patients. Seven patients had concomitant Down`s syndrome. All patients had large left-to-right shunt[mean pulmonary to systemic flow ratio 3.5 $\pm$2.2 ranging from 0.68 to 10.0] and high pulmonary systolic pressure[mean 74$\pm$18.8mmHg, ranging from 35 to 110]. In 11 patients, one patch technique was used to close the atrial and ventricular septal defect and 16 patients were undergone by two patch technique. We urgently managed only one patient by pulmonary artery banding whose anatomy was Rastelli type C and severe mitral regurgitation was identified. Postoperative complete A - V block was noted in 3 patients, two of whom were dead in operating room due to combined LVOTO and myocardial failure, and one patient with Rastelli type C was undergone by VVI type permanent pacemaker insertion 1wk later after two patch technique, but we had to manage him by modified Konno operation and total correction due to LVOTO and VSD leakage and severe mitral regurgitation 3 years later. Another two reoperation cases due to severe mitral regurgitation after two patch technique were undergone, one of whom we managed by mitral annuloplasty 3 months later but aggravated mitral regurgitation made us to control him by MVR 3 months later. Another one case of VSD leakage and tricuspid regurgitation was managed by total correction but she died of respiratory insufficiency 14 days later. We experienced pulmonary hypertensive crisis in 3 patients, who were dead in two cases comparing with one control case. So operative mortality is 9/27[33.6%], in one patch group of 3/11[29.2%] comparing with two patch group of 6/16[37.5%]. In summary, causes of death were pump weaning failure, myocardial failure and low cardiac output syndrome and pulmonary hypertensive crisis, resp. failure, complete AV block. Mean follow up period is 15.8$\pm$10.7 months[ranging from 3months to 37 months]

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.166-170
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• 2010

To numerically calculate electromagnetic scattering from the electrical-large three-dimensional(3D) objects, the high-frequency approaches have been usually applied, but the accuracy and feasibility of these geometrical and physical optics(GO-PO) approaches, to some extent, are remained to be improved. In this paper, a new framework is developed for calculation of the near-field scattering field of an electrical-large 3D target by using a multilevel fast multipole algorithm(MLFMA) and generation of radar images by using a fast back-projection(FBP) algorithm. The MPI(Message Passing Interface) parallel computing is carried out to multiply the calculation efficiency greatly. Finally, a simple example of perfectly electrical conducting(PEC) patch and a canonical case of Fighting Falcon F-16 are presented.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.8-16
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• 2012

The objective of this study was to identify bacterial antagonists of R. solani AG2-2 (IV) on zoysiagrass and to evaluate their antifungal activity in vitro and in vivo to select an antagonistic isolate. Antagonistic isolates that inhibit large patch disease caused by R. solani AG2-2 (IV) in zoysiagrass were selected from several soils, and their antagonistic activities were investigated in vitro and in vivo. Of 216 bacterial isolates, 67 inhibited several plant pathogenic fungi. The isolates that inhibited stem-segment colonization by R. solani AG2-2 (IV) in zoysiagrass were tested in a growth chamber. Eleven isolates were active as plant growth promoting isolates. Among them, five plant growth promoting isolates and their concentration dependent efficiency on zoysiagrass following inoculation with R. solani AG2-2 (IV) was evaluated. Isolate H33 was one of the potential antagonistic isolates, and it was further tested against various plant pathogens. H33 not only suppressed the disease caused by R. solani AG2-2 (IV) on zoysiagrass but also promoted leaf weight and leaf height of zoysiagrass under growth chamber and greenhouse conditions. The H33 isolate, which belongs to Streptomyces arenae, was identified through physiological, biochemical, and 16S rDNA studies. Further studies will investigate the cultural characterization of S. arenae H33 and isolation and identification of antifungal substance produced by S. arenae H33.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.492-500
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• 2015

Our previous report demonstrated successful isolation of soil-borne bacteria that suppressed the potential of Rhizoctonia solani AG2-2 (IV) causing turfgrass large patch disease when applied to Korean lawngrass (Zoysia japonica). The current study aimed to uncover the mechanisms of this antagonism of Rhizoctonia solani and to define culture conditions for the isolated microbes. We found that two Bacillus isolates, I-009 and FRIN-001-1 strains, produced cellulase and siderophore, but not chitinase, while the Pseudomonas YPIN-022 strain was found to release only siderophore, implying that three antagonistic bacteria commonly interrupt Fe uptake by the large patch pathogen. The I-009 and FRIN-001-1 isolates grew best at 35 and $30^{\circ}C$ in growth medium of pH 5 to 8 for 32 and 28 h, respectively, while optimum growth for the YPIN-022 strain was found at $35^{\circ}C$ at pH 5 to 9 for 24 h. Good growth of I-009 and YPIN-022 over 24 h was obtained in M9 minimal medium supplemented with 1% sucrose, 0.5% yeast extract and 0.1% potassium chloride. FRIN-001-1 grew well in M9 medium with 1% mannitol, 0.5% yeast extract and 0.1% potassium phosphate dibasic.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.657-665
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• 2013

A large patch disease caused by Rhizoctonia solani AG2-2 (IV) is a serious problem in Korean lawngrass (Zoysia japonica) sites including golf courses and sports fields in Korea. Antagonistic microorganisms against R. solani AG2-2 (IV) were isolated from various forest and crop soil sources in Southern Korea. Among the 61 isolates, I-009, FRIN-001-1, and YPIN-022 strains showing dramatic inhibition of the mycelial growth of R. solani AG2-2 (IV) in the pairing culture were selected as the most potential antagonistic microorganisms for this study. Based on the 16s RNA sequence comparison, I-009 and FRIN-001-1 isolates were identified as Bacillus spp., while YPIN-022 isolate belongs to the genus Pseudomonas. The greater inhibition (clear) zone between two edges of the selected and pathogenic microbes ranged from 11 to 15 mm in three selections, but the others averaged to 7 mm out of 30 mm distance. In another antifungal test using culture filtrate, those three isolates represented a range of 51.7 to 63.5% suppression potential. The selected isolates also inhibited significantly the stem-segment colonization by R. solani AG2-2 (IV) in vivo test by 28.1%, 43.0%, and 23.7% when inoculated with I-009, FRIN-001-1, and YPIN-022, respectively. The highest antagonistic activity for the large patch disease was demonstrated by the isolate FRIN-001-1, which will be useful for developing a bio-pesticide against Rhizoctonia.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.137-144
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• 2007

To investigate the effect of large patch infection on oxidative stress induction, super-oxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were compared between pathogen-infected and healthy (control) zoysiagrass. The sampling for leaves and roots were carried out every 2 days for a period of 6 days. The SOD activity was not significantly affected by pathogen-infection until day 2, but significant increase of both leaves (+48%) and roots (+49%) were observed at day 6 compared with control. The CAT activity was remarkedly increased by +25% in leaves and +101% in roots within the first 2 days and then rapidly decreased. The POD activity in pathogen-infected leaves was significantly increased by 74% at day 6. The increase of POD activity in pathogen-infected roots was 2-fold higher than that of the control at day 6. These results indicated that large patch-infection induce oxidative stress, and that SOD-CAT-POD antioxidant system of zoysiagrass was effectively operated.

• Journal of Chest Surgery
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• v.28 no.7
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• pp.721-725
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• 1995

One case of surgical correction of a large aortopulmonary window in a 4 months old female is reported in detail. Clinical symptoms consisted of fatigue when feeding and recurrent upper respiratory tract infection. Under cardiopulmonary bypass with moderate hypothermia and cardioplegic arrest of the heart, the aortopulmonary window was approached through a vertical incision at the anterior wall of window itself. The defect was closed with pericardial patch using continuous suture posteriorly and sandwitch technique anteriorly. The patient was weaned from the cardiopulmoanry bypas without hemodynamic problem and postoperative course was uneventful. This surgical technique is recommandable as it provides good exposure of the defect and can be performed easily and safely.