• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.56-56
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• 2020

감초는 다년생 콩과(Leguminocae) 식물로 국내에서 시중가격이 높은 만주감초가 일부 재배되고 있다. 우리나라에서 감초 재배법이 불완전한 상황에서 한반도의 기후변화에 의한 온도 상승은 약용작물의 생산 및 품질에 많은 영향을 미칠 것으로 예상되므로 본 연구에서는 재배환경 중 온도 조건만 조절할 수 있는 온도구배터널(temperature gradient tunnel system)을 이용하여 4개의 T1(외기온도+0.5~1.3℃), T2(+1.3~2.2℃), T3(+2.2~3.2℃), T4(+3.2~4.0℃) 처리로 온도구배 하여 4년생 만주감초(Glycyrrhiza uralensis F.)를 재배하였다. 지하부가 오래된 모주와 신초1의 경우 저온(T1)과 중간구간(T2, T3)에서 초장과 총화수가 우세하였고, 번식이 가장 늦은 신초2의 경우 중간구간(T2, T3)에서의 생육 및 개화반응이 뚜렷했다. 각 온도처리구마다 3개의 감초 개체를 선발하여 모주의 정단으로부터 5개의 성엽을 채취하였다. Reverse transcription quantitative PCR (RT-qPCR)은 AccuPower® GreenStar^TM RT-qPCR Master Mix (Bioneer, Korea)를 이용하여 진행되었다. Primer 디자인은 NCBI Primer-blast 프로그램을 사용해 제작하였고 ABI StepOne real time system (Applied Biosystem)의 melting curve analysis에서 one-peak test를 통해 gene specific primer임을 확인하였다. 각 온도처리구의 감초 잎에서 RNA를 추출하였고, RT-qPCR을 통해 감초의 유전자 발현양상을 비교, 분석하였다. Phytochrome interacting factor 4 (PIF4)는 식물 호르몬을 유발하는 전사조절을 조정함으로써 고온 신호전달에 핵심적인 역할을 수행한다. 활성화된 Phytochrome B(PhyB)는 PIF4의 활성을 억제한다고 알려졌다. Eukaryotic initiation factors(eIFs)는 mRNA 번역 개시인자로 유전자 발현과 특정 단백질 생산을 조절하는 역할을 한다. 본 결과는 온도조건에서 반응하는 생리적 변화를 전사체 수준에서 조사 분석하여 생리해석의 기초자료로 활용, 국내 감초 재배를 위한 환경조건 구명 및 적지 선정 기초자료로서 활용을 기대한다.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.727-738
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• 2023

In concrete, the interface between the aggregate and cement paste is often the most critical factor in determining strength, representing the weakest zone. Lightweight aggregate, produced through expansion and firing of raw materials, features numerous surface pores and benefits from low density; however, its overall aggregate strength is compromised. Within concrete, diminished aggregate strength can lead to aggregate fracture. When applying lightweight aggregate to concrete, the interface strength becomes critical due to the potential for aggregate fracture. This study involved coating the surface of the aggregate with blast furnace slag fine powder to enhance the interfacial strength of lightweight aggregate. The impedance of test specimens was measured to analyze interface changes resulting from this surface modification. Experimental results revealed a 4% increase in compressive strength following the coating of the lightweight aggregate surface, accompanied by an increase in resistance values within the impedance measurements corresponding with strength enhancement.

• Computers and Concrete
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• v.33 no.2
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• pp.175-193
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• 2024

Researchers have embarked on an active investigation into the feasibility of adopting alternative materials as a solution to the mounting environmental and economic challenges associated with traditional concrete-based construction materials, such as reinforced concrete. The examination of concrete's mechanical properties using laboratory methods is a complex, time-consuming, and costly endeavor. Consequently, the need for models that can overcome these drawbacks is urgent. Fortunately, the ever-increasing availability of data has paved the way for the utilization of machine learning methods, which can provide powerful, efficient, and cost-effective models. This study aims to explore the potential of twelve machine learning algorithms in predicting the tensile strength of geopolymer concrete (GPC) under various curing conditions. To fulfill this objective, 221 datasets, comprising tensile strength test results of GPC with diverse mix ratios and curing conditions, were employed. Additionally, a number of unseen datasets were used to assess the overall performance of the machine learning models. Through a comprehensive analysis of statistical indices and a comparison of the models' behavior with laboratory tests, it was determined that nearly all the models exhibited satisfactory potential in estimating the tensile strength of GPC. Nevertheless, the artificial neural networks and support vector regression models demonstrated the highest robustness. Both the laboratory tests and machine learning outcomes revealed that GPC composed of 30% fly ash and 70% ground granulated blast slag, mixed with 14 mol of NaOH, and cured in an oven at 300°F for 28 days exhibited superior tensile strength.

• Steel and Composite Structures
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• v.52 no.3
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• pp.293-312
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• 2024

Researchers are actively investigating the potential for utilizing alternative materials in construction to tackle the environmental and economic challenges linked to traditional concrete-based materials. Nevertheless, conventional laboratory methods for testing the mechanical properties of concrete are both costly and time-consuming. The limitations of traditional models in predicting the tensile strength of concrete composited with geopolymer have created a demand for more advanced models. Fortunately, the increasing availability of data has facilitated the use of machine learning methods, which offer powerful and cost-effective models. This paper aims to explore the potential of several machine learning methods in predicting the tensile strength of geopolymer concrete under different curing conditions. The study utilizes a dataset of 221 tensile strength test results for geopolymer concrete with varying mix ratios and curing conditions. The effectiveness of the machine learning models is evaluated using additional unseen datasets. Based on the values of loss functions and evaluation metrics, the results indicate that most models have the potential to estimate the tensile strength of geopolymer concrete satisfactorily. However, the Takagi Sugeno fuzzy model (TSF) and gene expression programming (GEP) models demonstrate the highest robustness. Both the laboratory tests and machine learning outcomes indicate that geopolymer concrete composed of 50% fly ash and 40% ground granulated blast slag, mixed with 10 mol of NaOH, and cured in an oven at 190°F for 28 days has superior tensile strength.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.189-196
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• 2007

The purpose of this study was to analyze steel corrosion resistance of concrete containing copper slag. The specimens were made with normal portland cement and pozzolan materials with various replacement ratio and with W/B ratio ranging from 35% to 55%. Compressive strength, coefficient of chloride diffusion, corrosion area ratio and weight reduction ratio were determinated for the test. The results show that the concrete with pozzolan materials is superior resistant to chloride ions compared to the concrete without pozzolan materials. It was observed that blast furnace slag replacement ratio of 20% gives the best results with respect to chloride ion penetration and corrosion tests and observed that copper slag replacement ratio of 10% gives the seperior resistance compared to normal concrete.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.129-137
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• 2005

In Korea, due to the insufficiency of natural aggregates and increasing needs of crushed stones, it is necessary to examine the alkali-silica reaction of the crushed stones. The reaction produces an alkali-silica reaction gel which can imbibe pore solution and swell to generate cracks that are visible In affected concrete. In general, crushed stones are tested by petrograptuc examination, chemical method and mortar-bar method, but the most reliable method Is mortar-bar test. This study tested alkali-silica reactivity of crushed stones of various rock types using ASTM C 227 and C 1260, and compared the results of two test methods. This study also analyzed effects of particle size and grading of reactive aggregate on alkali-silica reaction expansion of mortar-bar. The effectiveness of mineral admixtures to reduce detrimental expansion caused by alkali-silica reaction was investigated through the ASTM C 1260 method. The mineral admixtures used were nv ash, silica fume, metakaolin and ground granulated blast furnace slag. The replacement ratios of 0, 5, 10, 15, 25 and $35\%$ were commonly applied for all the mineral admixtures and the replacement ratios of 45 and $55\%$ were additional applied for the admixtures that could maintain workability. The results indicate that replacement ratios of $25\%$ for ay ash, $10\%$ for silica fume, $25\%$ for metakaolin or $35\%$ for ground granulated blast furnace slag were most effective to reduce alkali-silica reaction expansion under the experimental conditions.

• Korean Journal of Dental Materials
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• v.45 no.4
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• pp.257-274
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• 2018

The purpose of this study was to evaluate the effect of acid-treatment conditions on the surface properties of the RBM (Resorbable Blast Media) treated titanium. Disk typed cp-titanium specimens were prepared and RBM treatments was performed with calcium phosphate ceramic powder. Acid solution was mixed using HCl, $H_2SO_4$ and deionized water with 4 different volume fraction. The RBM treated titanium was acid treated with different acid solutions at 3 different temperatures and for 3 different periods. After acid-treatments, samples were cleaned with 1 % Solujet solution for 30 min and deionized water for 30 min using ultrasonic cleanser, then dried in the electrical oven ($37^{\circ}C$). Weight of samples before and after acid-treatment were measured using electric balance. Surface roughness was estimated using a confocal laser scanning microscopy, crystal phase in the surface of sample was analyzed using X-ray diffractometer. Surface morphology and components were evaluated using Scanning Electron Microscope (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoemission Spectroscopy (XPS). Values of the weight changes and surface roughness were statistically analyzed using Tukey-multiple comparison test (p=0.05). Weight change after acid treatments were significantly increased with increasing the concentration of $H_2SO_4$ and temperature of acid-solution. Acid-treatment conditions (concentration of $H_2SO_4$, temperature and time) did not produce consistent effects on the surface roughness, it showed the scattered results. From XRD analysis, formation of titanium hydrides in the titanium surface were observed in all specimens treated with acid-solutions. From XPS analysis, thin titanium oxide layer in the acid-treated specimens could be evaluated. Acid solution with $90^{\circ}C$ showed the strong effect on the titanium surface, it should be treated with caution to avoid the over-etching process.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.288-291
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• 2009

A new commercial rice variety "Donghaejinmi" is a japonica rice (Oryza sativa L.) with lodging resistance and high grain quality. It has been developed by the rice breeding team of Yeongdeog Substation, National Institute of Crop Science (NICS), RDA. This variety was derived from a cross between "Milyang 64" as a resistance source of brown planthopper (Bph) and "Milyang 165" as grain quality source. The donor parent, "Milyang64" has been backcrossed three times with recurrent parent, "Milyang165" and selected by the pedigree breeding method. The pedigree of "Donghaejinmi", designated as "Yeongdeog 41" in 2003, was YR21259-B-B-68-1. It has a short culm length with 69 cm and medium-late growth time. This variety is resistant to stripe virus and moderately resistant to leaf blast disease with durable resistance. It also has tolerance to unfavorable environment such as cold, dried wind and storm. Milled rice kernel of "Donghaejinmi" is translucent, clear in chalkness and good at eating quality in panel test. The merit of this variety is high head rice ratio, which is essential element to produce an article of superior quality rice brand. The yield potential of "Donhaejinmi" in milled rice is about 6.05 MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to Yeongnam inland plains and eastern costal area of Yeongnam province.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.515-519
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• 2009

"Sangok", is a new japonica rice variety (Oryza sativa L.), which is a midium maturing ecotype developed by the rice breeding team of National Yeongnam Agricultural Experiment Station (NYAES) in 2003. This variety was derived from the cross of Milyang 101/YR8697Acp97 (in 1988/1989 winter) and selected by combination of the bulk and pedigree breeding. The pedigree of Sangokbyeo, designated as Milyang 182 in 2000, was YR12950-B-B-B-19-2-4-2-2. It has about 79cm stature in culm length and is medium maturing. This variety is resistant to bacterial blight ($K_1$, $K_2$, and $K_3$), stripe virus and moderately resistant to leaf blast disease. Milled rice kernels of "Sangok" is translucent, clear in chalkness and good at eating quality in the panel test. The yield potential of "Sangok" in milled rice is about 5.16MT/ha at ordinary fertilizer level of local adaptability test. This cultivar would be adaptable to the southern plain of Korea below the Chungnam province by latitude from ordinary transplanting to transplanting after barley harvest.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.18-25
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• 2001

Ethanol extracts from 46 plants were tested for their fungicidal activity against six plant diseases consisting of Maynaporthe grisea, Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia recondita, and Erysiphe graminis in the greenhouse studies. Strong activity at 5 and 10 mg/pot was produced from the extracts of Helianthus annuus flowers and Zea mays leaves against P. grisea. In a test with B. cineara, extracts of H. annuus leaves, H. annuus flowers, Chrysanthmum coronarium var. spatiosum, Cucurbita moschata seeds, Lycopersicon esculentum, Z. mays, and Z. mays leaves had strong activities at 5 mg/pot. In a test with P. recondita, strong activity was obtained from the extracts of Capsicum frutescens, C. moschata seeds, H. annuus seeds, L. esculentum, and Malva veticillata at 5 mg/pot. Against E. graminis, extracts of Cucumis sativus, H. annuus seeds, Salanum tuberosum, Z. mays, and Z. mays leaves produced strong activities at 10 mg/pot. All the extracts were ineffective against P. infestans and R. solani. Among seven extracts tested, the extracts of H. annuus leaves and flowers were highly effective against all the strains of B. cinerea resistant to carbendazim, procymidone, and diethofencarb. Furthermore, potent fungicidal activity was produced from the extracts of C. coronarium var. spatiosum and C. moschata seeds against the SSR, SRR, and RSR strains of B. cinerea, and Z. mays and Z. mays leaves against SSR and RSR. Extract of L. esculentum showed very strong activity only against RRS of B. cinerea.