• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.520-524
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• 2009

A newly developed rice variety "Pungmi 1" is a japonica rice(Oryza sativa L.) with high grain quality and multi-resistant to diseases. It was developed by the rice breeding team of Yeongnam Agricultural Research Institute (YARI), RDA. in 2004. This variety derived from a cross between "YR13616Acp 1", having short culm and multi-resistance to biotic stresses and "Milyang 122" with good grain quality. It has short stature of 73cm in culm length and mid-early flowering date of Aug. 13. This variety is moderately resistant to leaf blast showing durable resistance of lower 10% diseased leaf araea in sequential planting meothod. Milled rice kernel of "Pungmi 1" is translucent, clear in chalkness and good at eating quality in panel test. Milling recovery and head rice ratios were comparable to Milyang 122, while it has low protein content. The milled rice yield potential of "Pungmi 1" is about 5.59 MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Yeongnam inland plains and southern coastal areas of Yeongnam province at ordinary transplanting as well as after barly cultivation.

• Korean Journal of Breeding Science
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• v.51 no.3
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• pp.222-233
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• 2019

'Haepum' is a bacterial blight-resistant, medium maturing rice cultivar with high grain quality. It was derived from a cross between 'Iksan493' (cultivar name 'Jinbaek') and the F₁ cross between 'Iksan495' ('Dacheong') and 'Iksan496' ('Jungmo1005'). Of these three cultivars, 'Jinbaek' is a bacterial blight-resistant mid-late maturing rice cultivar with high grain quality, 'Dacheong' is a mid-late maturing rice cultivar with multiple resistance to disease and insects, and 'Jungmo1005' is a mid-late maturing rice cultivar with lodging tolerance. To develop fixed lines, the anther culture method was applied to F₁ plants. The cultivar 'Haepum' was selected using the pedigree method, yield trials, and local adaptability tests. The heading date of 'Haepum' was August 11^th, three days earlier than that of 'Nampyeong' cultivar. Haepum' is a cultivar tolerant to lodging and it has short culms. Due to its low rate of viviparous germination, 'Haepum' could be useful for preventing pre-harvest sprouting in cultivation of medium maturing rice in the southern plain area of Korea. 'Haepum' carries two bacterial blight resistance genes (Xa3 and xa5), and in our study, it exhibited high-level and broad-spectrum resistance against bacterial blight, including K3a, the most virulent race in Korea. 'Haepum' is also resistant to the rice stripe virus and moderately resistant to rice blast. The yield of 'Haepum' was similar to that of 'Nampyeong'. 'Haepum' showed excellent grain appearance and good taste of cooked rice, and therefore it could contribute to the development of bacterial blight-resistant rice cultivars of improved quality. 'Haepum' would be suitable for cultivation in the southern plain area of Korea as well as in bacterial blight-prone areas. (Registration No. 6068)

• Journal of Korean Society of Environmental Engineers
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• v.34 no.4
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• pp.223-231
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• 2012

The purpose of this study is to investigate basically the mechanism of heat transfer by the resolution of complex fluid flow inside a sophisticated designed screw dryer for the treatment of sewage sludge by using numerical analysis and experimental study. By doing this, the result was quite helpful to obtain the design criteria for enhancing drying efficiency, thereby achieving the optimal design of a multiple screw type dryer for treating inorganic and organic sludge wastes. One notable design feature of the dryer was to bypass a certain of fraction of the hot combustion gases into the bottom of the screw cylinder, by the fluid flow induction, across the delicately designed holes on the screw surface to agitate internally the sticky sludges. This offers many benefits not only in the enhancement of thermal efficiency even for the high viscosity material but also greater flexibility in the application of system design and operation. However, one careful precaution was made in operation in that when distributing the hot flue gas over the lump of sludge for internal agitation not to make any pore blocking and to avoid too much pressure drop caused by inertial resistance across the lump of sludge. The optimal retention time for rotating the screw at 1 rpm in order to treat 200 kg/hr of sewage sludge was determined empirically about 100 minutes. The corresponding optimal heat source was found to be 150,000 kcal/hr. A series of numerical calculation is performed to resolve flow characteristics in order to assist in the system design as function of important system and operational variables. The numerical calculation is successfully evaluated against experimental temperature profile and flow field characteristics. In general, the calculation results are physically reasonable and consistent in parametric study. In further studies, more quantitative data analyses such as pressure drop across the type and loading of drying sludge will be made for the system evaluation in experiment and calculation.

• Journal of fish pathology
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• v.30 no.2
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• pp.89-96
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• 2017

The majority of freshwater ornamental fish are imported and distributed domestically, causing high risk of exposure to exotic pathogens and drug resistant bacteria in Korea. Aeromonas hydrophila is known as a common species of fresh water bacteria and opportunistic fish pathogen, as well as a species causing zoonotic infection. In this study, we isolated motile aeromonads from various imported freshwater ornamental fish and studied the characters of the isolates. Imported freshwater ornamental fish were purchased on day 1 after the fish were deposited in the aquarium. Bacteria were isolated from the liver, kidney and spleen of fish using 0.5% NaCl containing tryptic soy agar medium. Bacteria were grouped on the basis of their morphological characteristics. The colonies with clear zone on starch-ampicillin agar (SA agar) were tentatively identified as Aeromonas spp. Two hundred and twenty-six strains, about 70% of total isolates were assumed to be Aeromonas spp. Nine isolates were further identified based on the result of the API 20E test and PCR using primers specific for A. hydrophila 16S rRNA gene. The isolates were identified as A. hydrophila and the API 20E test showed differences in trisodium citrate, D-sucrose, D-melibiose, amygdalin and L-arabinose availability between the nine isolates and standard A. hydrophila. The susceptibilities of the isolated bacteria to 10 antibacterial agents were confirmed by the disk diffusion method. Isolated strains were found to be resistant to amoxicillin and ampicillin and sensitive to florfenicol. However, 7 isolates showed multiple drug resistances to erythromycin, oxytetracycline, nalidixic acid etc. Pathogenicity of the isolates was determined by the artificial challenge test on goldfish (Carassius auratus). Three isolates caused 60 ~ 80% mortality in goldfish within 5 days after the initiation of challenge. These results indicate that multiple drug resistant, highly pathogenic and exotic A. hydrophila can spread to domestic aquarium and the preventive treatment of fish before sale is necessary.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.1
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• pp.93-100
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• 2015

Modern wooden structures usually are connected with steel fastener type connectors. And joints using multiple connectors in wooden structures will form semi-rigid connection. If connection in wooden structure would be designed to be pinned joint, the underestimate for loads transmitted through connection, would result in the deficient capacity of resistance in connection. And if joints in wooden structures would be assumed to be fully-rigid joint, amount of fasteners needed at the connection could be excessively increased. It will give a bad effect in the view of beauty, constructability and economy. Estimate for the reasonable stiffness of connection might be essential in design of reasonable connection in wooden structure. This paper will suggest analysis modelling technique that can represent approximate stiffness of connections using a common analysis program for double shear connection in order to give help in performing easily the design of wooden structure. It is verified that the suggested approximate analysis modelling technique could represent the behavior in connection by comparing the analysis results with test results for tensile, bending moment.

• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.475-483
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• 2012

High capacitance X5R MLCCs based on $BaTiO_3$ ceramic dielectric layers exhibit a single broad, asymmetric arc shape impedance and modulus response over the wide frequency range between 1 MHz to 0.01 Hz. Analysis according to the conventional brick-layer model for polycrystalline conductors employing a series connection of multiple RC parallel circuits leads to parameters associated with large errors and of little physical significance. A new parametric impedance model is shown to satisfactorily describe the experimental spectra, which is a parallel network of one resistor R representing the DC conductivity thermally activated by 1.32 eV, one ideal capacitor C exactly representing bulk capacitance, and a constant phase element (CPE) Q with complex capacitance $A(i{\omega})^{{\alpha}-1}$ with ${\alpha}$ close to 2/3 and A thermally activated by 0.45 eV or ca. 1/3 of activation energy of DC conductivity. The feature strongly indicate the CK1 model by J. R. Macdonald, where the CPE with 2/3 power-law exponent represents the polarization effects originating from mobile charge carriers. The CPE term is suggested to be directly related to the trapping of the electronic charge carriers and indirectly related to the ionic defects responsible for the insulation resistance degradation.

• Journal of Life Science
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• v.30 no.9
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• pp.798-803
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• 2020

Late in the 1960s, South Korea established cultivation technology and began breeding new "Tongil" type rice cultivars by crossing indica and japonica. To date, this cultivation technique has been used to produce a wide variety of cultivars to meet consumer preferences and adapt to extreme weather conditions. Once major genetic traits are no longer segregated through advanced generations, varieties obtained from a cross between different crops may become a new variety. In this study, we confirmed the agronomic traits of F₄, F₅, and F₆ by advanced generation a population in which drought tolerance and brown planthopper (BPH) resistance were crossed. HV23, Ilmi/HV23, and Drimi2ho/HV23 were used. HV23 was drought-tolerant, and Drimi2ho was resistant to BPH. As a result, it was possible to consider that the agronomic traits were fixed because none of them showed a significant difference from the others. While it takes more than 10 years for the pedigree method of breeding, this study confirmed that the agronomic traits were fixed in 4-6 years. In the future, we will investigate the homology of the CaMsrB2 gene and the Bph1 gene, to confirm that both genes are closely related to each other, and analyze the stable inheritance of the introduced gene for multiple successive generations.

• International Journal of High-Rise Buildings
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• v.9 no.2
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• pp.127-154
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• 2020

Disproportionate collapse triggered by local structural failure may cause huge casualties and economic losses, being one of the most critical civil engineering incidents. It is generally recognized that ensuring robustness of a structure, defined as its insensitivity to local failure, is the most acceptable and effective method to arrest disproportionate collapse. To date, the concept of robustness in its definition and quantification is still an issue of controversy. This paper presents a detailed review on about 50 quantitative measures of robustness for building structures, being classified into structural attribute-based and structural performance-based measures (deterministic and probabilistic). The definition of robustness is first described and distinguished from that of collapse resistance, vulnerability and redundancy. The review shows that deterministic measures predominate in quantifying structural robustness by comparing the structural responses of an intact and damaged structure. The attribute-based measures based on structural topology and stiffness are only applicable to elastic state of simple structural forms while the probabilistic measures receive growing interest by accounting for uncertainties in abnormal events, local failure, structural system and failure-induced consequences, which can be used for decision-making tools. There is still a lack of generalized quantifications of robustness, which should be derived based on the definition and design objectives and on the response of a structure to local damage as well as the associated consequences of collapse. Critical issues and recommendations for future design and research on quantification of robustness are provided from the views of column removal scenarios, types of structures, regularity of structural layouts, collapse modes, numerical methods, multiple hazards, degrees of robustness, partial damage of components, acceptable design criteria.

• Journal of Life Science
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• v.18 no.8
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• pp.1083-1089
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• 2008

We investigated the molecular epidemiological characteristic of methicillin resistant Staphylococcus aureus (MRSA) strains isolated from stool samples in Busan from 2004 to 2006. Among 142 isolates of S. aureus, 49 isolates (34.5%) were confirmed as MRSA. With the antimicrobial susceptibility tests, 37 isolates (75.5%) showed multiple resistance to more than 10 antibiotics, but all isolates were sensitive to vancomycin. All of MRSA had enterotoxin A in 30.6%, B 4.1%, C 8.3%, D, C/G, A 2.0% and None 51%. PFGE of SmaI-digested chromosomal DNA was performed on 49 sporadic MRSA isolates. Restriction fragment patterns consisted of 8 to 14 fragments ranged in size from 48.5 to 630.5 kbp. We could divided the isolates into 7 groups ($I{\sim}VII$) by analyzing PFGE patterns. Group I subdivided as 2 subgroups and 17 (34.7%) strains belong to the group I. Dendrogram of PFGE patterns showed that MRSA strains in Busan were heterogeneous but we could find out minor homogeneity in hospital.

• Research in Plant Disease
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• v.8 no.3
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• pp.146-161
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• 2002

Incidence of soilborne diseases, as a major cause of failure of continuous monocropping becomes severe in recent years. For examples, recent epidemics of club root of chinese cabbage, white rot of garlic, bacterial wilt of potato, pepper phytophthora blight, tomato fusarium wilt and CGMMV of watermelon are the diseases that require urgent control measures. Reasons for the severe incidence of soilborne diseases are the simplified cropping system or continuous monocropping associated with allocation of major production areas of certain crop and year-round cultivation system that results in rapid degradation of soil environment. Neglect of breeding for disease resistance relative to giving much emphasis on high yield and good quality, and cultural methods putting first on the use of chemical fertilizers are thought to be the reason. Counter-measures against soilborne disease epidemics would become most effective when the remedies are seeded for individual causes. As long-term strategies, development of rational cropping system which fits local cropping and economic condition, development and supply of cultivars resistant to multiple diseases, and improvement of soil environment by soil conditioning are suggested. In short-term strategies, simple and economical soil-disinfestation technology, and quick and accurate forecasting methods for soilborne diseases are urgent matter far development. for these, extensive supports are required in governmental level for rearing soilborne disease specialists and activation of collaborating researches to solve encountering problems of soilborne diseases.