• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.529-533
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• 2018

Hyowon6, a mid-late maturing, good eating quality rice variety with multi-resistance, was developed by the rice breeding team of Pusan National University in 2013. This variety was derived from a cross between Hwayeong (as a multi-resistant parent) and Koshihikari (as a good eating quality parent). Selection by the pedigree breeding method was carried out until the $F_8$ generation. A promising line, JS14-12-36-8-5-3-1-1-1, was developed and designated as HY103 in 2013. This variety headed on August 22, which was 11 days later than that of Hwayeong. The culm length and panicle length of Hyowon6 was 85.7 cm and 21.1 cm, respectively. The number of panicles per hill was 14.5 and the number of grains per panicle was 101.7. The ratio of ripened grain was approximately 92% and the 1,000-grain weight was approximately 21.36 g for brown rice, which were similar to those of Hwayeong. Hyowon6 was moderately resistant to lodging and also to neck blast, leaf blight, and stripe virus. The glossiness value of Hyowon6 was 83, which was considerably higher than that of Hwayeong.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.778-781
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• 2016

Sea urchin skeleton (SUS) generated from production of sea urchin eggs was used as a biodegradable film base material, and its composite film with gelatin was prepared. In addition, Robinia pseudoacacia flower extract (RFE) was incorporated into the film-forming solution to provide antioxidant and anti-microbial activities. The tensile strength (TS) of the SUS/gelatin composite films increased with increasing gelatin content, whereas elongation at break (E) decreased. Among the composite films, SUS/gelatin film at a ratio of 8:2 (w/w) exhibited the most desirable TS and E values. Furthermore, SUS composite film containing RFE showed a reduced TS and increased E compared to the control film. Based on 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays and disc diffusion results against growth of Listeria monocytogenes, antioxidant and anti-microbial activities of films increased with increasing RFE concentration. Consequently, SUS composite film containing RFE showed proper physical properties as well as antioxidant and anti-microbial activities. These results indicate that SUS can be used as a film base material while the SUS composite film containing RFE can be utilized as active packaging.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.358-361
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• 1998

This study was carried out to develop a short term hardening method of tree seedlings of Rhus chinensis Mill., Evodia daniellii Hemsley and Parthenocissus tricuspidata(Sieb. et Zucc.) Planck for afforestation on a concave and a crack of cut-rock slope. The seedlings were grown in a cylinder shaped pot made of polyvinyl net with the soil media of peatmoss, vermiculite, clay, compost, fertilizer, and absorbant(40:25:19:15:1:0.1, v:v). They were cultivated in a greenhouse for four months and in field condition for two months. During the last three months of the growing period the seedlings were hardened by periodic desiccation and irrigation in 4 to 10 days interval. The hardened seedlings showed lower leaf water potential, higher leaf osmotic pressure, and lower T/R ratio than those before the hardening. The hardened seedlings survived well on the soil medium in the concave of cut-rock slope.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.203-210
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• 2005

The penetration and viscosity tests have been used for the evaluation of the aged asphalt binder performance change. The improved test method has been required because the conventional tests could not evaluate the viscoelastic characteristics and the real behaviour of the aged asphalt binder. The conventional test methods using a different short term aged asphalt binder were tested and the test results were expressed as the penetration index and the residual penetration. The oscillatory and rotational mode tests were performed to find out the rheological characteristics of the short term aged asphalt binder in this study. The test results showed that the change of testing frequency, the speed of the vehicle effects the complex modules and phase angles. The creep compliance and shear viscosity also showed the different test results when the short term aged asphalt binders were tested. The rheological behavior should consider when the pavement design is conducted.

• Korean Journal of Agricultural Science
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• v.15 no.2
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• pp.132-137
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• 1988

Twenty-six cabbage rot samples were collected from markets and main cabbage-growing areas in Korea and isolates of pathogenic bacteria were obtained from the collection. According to their bacteriological characteristics and pathogenicity, the majority of rot bacteria were identified as Erwinia carotovora subsp. carotovora. Pseudomollas cichorii. P. viridiflava and Xanthomonas campestris pv. campestri. Among these four species, E. carotovora subsp. carotovora and X. campestris pv. campestris were found to cause serious damage to cabbage production throughout Korea. Two species of the causal bacteria were sometimes isolates from a single cabbage rot sample and it suggest that the mixed infection of the two bacteria be occurred under field condition.

• International Journal of Highway Engineering
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• v.19 no.1
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• pp.45-52
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• 2017

PURPOSES : The main purpose of this study is to develop a high elastic modulus and low-shrinkage roller-compacted concrete base (RCCB) in order to prevent fatigue cracking and reflective cracking in the asphalt surface layer of composite pavement. Using a rigid base material with low shrinkage can be a solution to this problem. Moreover, a strong rigid base with high elastic modulus is able to shift the location of critical tensile strain from the bottom of the asphalt layer to the bottom of the rigid base layer, which can prevent fatigue cracking in the asphalt layer. METHODS : Sensitivity analysis of composite pavement via numerical methods is implemented to determine an appropriate range of elastic modulus of the rigid base that would eliminate fatigue cracking. Various asphalt thicknesses and elastic moduli of the rigid base are used in the analysis to study their respective influences on fatigue cracking. Low-shrinkage RCC mixture, as determined via laboratory testing with various amounts of a CSA expansion agent (0%, 7%, and 10%), is found to achieve an appropriate low-shrinkage level. Shrinkage of RCC is measured according to KS F 2424. RESULTS : This study shows that composite pavements comprising asphalt thicknesses of (h1) 2 in. with E2 > 19 GPa, 4 in. with E2 > 15 GPa, and 6 in. with E2 > 11 GPa are able to eliminate tensile strain in the asphalt layer, which is the cause of fatigue cracking in this layer. Shrinkage test results demonstrate that a 10% CSA RCC mixture can reduce shrinkage by 84% and 93% as compared to conventional RCC and PCC, respectively. CONCLUSIONS : According to the results of numerical analyses using various design inputs, composite pavements are shown to be able to eliminate fatigue cracking in composite pavement. Additionally, an RCC mixture with 10% CSA admixture is able to reduce or eliminate reflective cracking in asphalt surfaces as a result of the significant shrinkage reduction in the RCC base. Thus, this low-shrinkage base material can be used as an alternative solution to distresses in composite pavement.

• Composites Research
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• v.23 no.3
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• pp.64-68
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• 2010

Expanded polystyrene(EPS) foams are often used in packaging to protect electrical appliances from impact loads. The energy absorbing performances of the EPS foams depend on several parameters such as density, microstructure and strain rate. Thus, the effects of the parameters on the strength of the EPS foams need to be investigated for an optimized packaging design by FEM. In this study, various EPS foams which have different densities were quasi-statically and dynamically loaded in order to obtain the stress-strain curves. EPS foams of various densities from 18.5 to 37.0kg/m3 were considered in the experiments. A drop-mass type apparatus was developed for the intermediate strain rate tests up to several hundreds/second. It was found from the experimental results that the strength of the EPS foams increase about 170% as the strain rate increases from 0.06/s to 60/s. Experimental results also showed that the strain rate sensitivity increases as the strain increases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.310-316
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• 1987

A field experiment was conducted to find out the effects of liming(soil pH) and sources of N on growing characters and yield of burley tobacco. Treatments consisted of liming(nonliming, liming to soil pH5.5 and 6.5) as the main plot and N sources(compound fertilizer of containing 3.9% NH$_4$-N and 6.1% NH$_2$-N, NaNO$_3$,(NH$_2$)$_2$CO and (NH$_4$)$_2$SO$_4$as the sub-plot. The growth of vegetative growing stage of limed plots were delayed(to compare the nonlimed plot) by influence of alkali. When the source on N was NaNO$_3$ the growth of vegetative growing stage was unfavorable and the yellowing of lower leaves of maturing stage was rapid. The yield and value of cured leaf was increased by increasing the rate of Ca(OH)$_2$, but there was no significant differences among the source of N. The yield response to liming was greater when the source of N was (NH$_4$)$_2$SO$_4$ than that of any other plots.

• Research in Plant Disease
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• v.8 no.2
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• pp.120-123
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• 2002

Occurrence of anthracnose on red pepper fruit was examined at 6 red pepper-growing regions including Yecheon, Andong, Euisong, Cheongsong, and Ponghwa in Kyungbuk province, Korea in 1999. The disease occurred firstly June 13 at Cheongsong, progressed gradually thereafteri and increased rapidly from late August. The average disease incidence with mid September was 30.4%. There was no significant difference in disease incidence among the regions examined. Correlation coefficient analysis of the disease incidence with weather factors revealed that it was significantly related to relative humidity, precipitation, rainy days, and duration of continuous rainy days. Most fungal isolates from the diseased fruit were Colletotichum gloeosporioides. In the in field experiment, unmature fruit was somewhat more susceptible to the disease than mature fruit. In the field experiment, the disease occurred severely in open fields, having the disease incidence of 12.1%; however, no disease was observed in the rain-proof fields. The anthracnose on red pepper fruit developed earlier and more severely in the successive cropping field with red pepper than the field having other crops. Removal of infected plant debris also delayed and reduced the disease occurrence, suggesting that plant debris infested with the anthracnose fungus serve as a primary inoculum source which may govern the severity of the disease in the field.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.2
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• pp.140-146
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• 2002

본 시험은 채종유박과 미강유박을 주원료로 하고 질소, 인산, 칼리의 함량이 7.23%이고 중금속이 거의 없이 개발된 유기질비료(크럼블-80)를 공시비료로 기비와 추비시비 방식의 포장시험을 통하여 토양과 한국잔디의 생육에 미치는 영향과 시비효율을 구명하여 올바른 시비방법 및 시비량을 제시하고자 2000년 4월부터 12월까지 경기도 용인시 소재 태광컨트리클럽 증식포(기비시험)와 경기도 파주시 소재 서서울컨트리클럽 10홀 티(추비시험)에서 실시하였다. 기비시험 결과, 엽록소 측정결과의 처리효과는 무처리구가 100일 때 관행구 117%, 관행구+크럼블-80 $150g/m^2$ 123%, 크럼블-80 $150g/m^2$ 115%, 크럼블-80 $300g/m^2$ 119%, 크럼블-80 $75g/m^2$ 102%로 효과가 있는 것으로 나타났다. 유기질비료인 크럼블-80은 시비량에 따라 엽록소 함량이 약간 증가되었으나 NPK와 혼합처리구에서 가장 높은 것은 공시비료의 단독처리보다는 복합비료와 혼용하는 것이 더 효과적인 것으로 나타났다. 추비시험 결과, 잔디생육기간 중 잔디건물중을 조사한 결과는 크럼블-80의 시용량이 많을수록 잔디건물중도 증가하였으며, 처리구에 따라 무처리구보다 5~45(%) 정도의 증수효과가 있는 것으로 나타났다. 그러나 엽록소함량은 처리구가 무처리구보다는 높았으나 골프코스에 필요한 녹색유지에는 부족하므로 화학비료와의 혼용시비가 필요하다고 판단된다. 본 시험결과로 볼 때 시험에 사용된 공시비료는 골프코스 잔디관리에 적합한 비료로 판단된다. 시험결과를 토대로 한 권장시비량은 기비시비의 경우 잔디식재 전에 공시비료 $300g/m^2$를 표토 10cm와 잘 혼합하여 시비하되, 추비시비는 공시비료와 화학비료와의 혼용시비가 필요하다고 판단된다.