• Title/Summary/Keyword: 불안정 조건

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A Temporal Structure Analysis of Forest Landscape Patterns using Landscape Indices in the Nakdong River Basin (경관지수를 활용한 낙동강 유역 산림경관의 시계열적 패턴 분석)

  • Jung, Sung-Gwan;Oh, Jeong-Hak;Park, Kyung-Hun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.2
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    • pp.145-156
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    • 2005
  • An artificial disturbance like forest fragmentation has affected the sustainability of forest ecosystem. Therefore, in order to manage the forest ecosystem efficiently needed to analyze quantity and quality (structural pattern) of forest simultaneously. This study analyzed the structural patterns of forest landscape to provide a basic data for evaluation and management of forest ecosystem in Nakdong River Basin during 10 years from 1980s to 1990s using landscape indices and GIS methods. Forest distribution maps and 6 landscape indices(LPI, PD, ED, MSI, CPLAND, IJI) for the analysis were reconstructed from land-cover maps constructed by Ministry of Environment and pearson correlation analysis. According to the structural analysis of forest landscape using landscape indices, the forest fragmentation of watersheds along the main stream of the Nakdong river was more severe than any other watersheds. Futhermore, the Nakong-sangju and Nakdong-miryang watersheds had unstable forest structures as well as least amount of forest quantity. Thus, these watersheds need significant amount of forest through a new forest management policy considering local environmental conditions. The connectivity between forests in local regions should be considered as well.

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Numerical Study on Rayleigh-Taylor Instability Using a Multiphase Moving Particle Simulation Method (다상유동형 입자법을 이용한 Rayleigh-Taylor 불안정성의 수치해석)

  • Kim, Kyung Sung;Koo, Bonguk;Kim, Moo-Hyun;Park, Jong-Chun;Choi, Han-Suk;Cho, Yong-Jin
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.20 no.1
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    • pp.37-44
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    • 2017
  • Complexity of multiphase flows due to existence of more than two interface including free-surface in one system, cannot be simulated easily. Since more than two fluids affect to flows and disturb interface, non-linearities such as instabilities can be appeared. Among several instabilities on multiphase flows, one of representative is Rayleigh-taylor instability. In order to examine in importance of density disparity, several cases with numerous Atwood number are set. Moreover, investigation of influence on initial disturbance were also considered. Moving particle simulation (MPS) method, which was employed in this paper, was not widely used for multiphase problem. In this study, by adding new particle interaction models such as self-buoyance correction, surface tension, and boundary condition at interface models, MPS were developed having more strength of physics and robust. By applying newly developed multiphase MPS, considered cases are performed and compared each other. Additionally, though existence of disagreement of magnitude of rising velocity between theoretical values from linear potential theory and that of numerical simulation, agreement of tendency can be proved of similarity of result. the discordance of magnitude can be explained due to non-linear effects on numerical simulation which was not considered in theoretical result.

A Novel Printable Time-temperature Integrator with Anthocyanidin, a Natural Coloring Matter (천연 색소인 안토시아니딘 기반의 인쇄형 시간-온도이력 지시계 개발)

  • Jang, Han Dong;Yang, Jung Hwa;Kim, Do Hyeon;Ahn, Myung Hyun;Han, Seo Hyeon;Lee, Seung Ju
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.24 no.2
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    • pp.49-56
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    • 2018
  • A novel printable time-temperature integrator (TTI) composed of a natural coloring matter, anthocyanidin, was developed. The anthocyanin was biochemically modified to change in color over week scale, compared to the original anthocyanin over month scale change. The anthocyanin extracted from strawberry was converted to its aglycone, anthocyanidin, by the treatment with ${\beta}-glucosidase$. The print paste was composed of the freeze-dried powder of anthocyanidin, pullulan, glycerol and distilled water, which was screen-printed. The TTI performance were examined in terms of kinetics and temperature dependency. The activation energy of anthocyanidin TTI was 86.92 kJ/mol. Compared with the activation energy of foods, the applicable food groups were found. Applicable food groups were chilled meat products and fish. The major benefits of the TTI were the printability to be practical in use and the eco-friendliness with the natural pigment.

The Effect of Auditory Condition on Voice Parameter of Orofacial Pain Patient (청각 환경이 구강안면 통증환자의 음성 파라미터에 미치는 영향)

  • Lee, Ju-Young;Baek, Kwang-Hyun;Hong, Jung-Pyo
    • Journal of Oral Medicine and Pain
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    • v.30 no.4
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    • pp.427-432
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    • 2005
  • This study have been compared and analyzed voice parameter under the condition of normal voice and auditory condition(noise and music) for 29 patients of orofacial pain and 31 normal people to investigate voice feature and vocal variation for auditory condition of orofacial pain patient. 1. Compared to normal voice, orofacial pain patient showed lower and unstable voice feature which has low F0 rate and high jitter and shimmer rate. 2. Voice of orofacial pain patient showed more relaxed and stable voice feature with low F0 and shimmer rate in the music condition than noise condition. 3. Normal people's voice has no significant difference between music and noise condition even though it has high F0 rate under the noise condition. As a result, orofacial pain patient showed difference of feature and different response for external auditory condition compared to normal voice. Providing of positive emotional environment such as music could be considered for better outcome of oral facial pain patient's functional disability.

Study on Physicochemical Properties of Pesticides. (II) Water Solubility, Hydrolysis, Vapor Pressure, and Octanol/water Partition Coefficient of Flupyrazofos (농약의 물리화학적 특성 연구 (II) Flupyrazofos의 수용성, 가수분해, 증기압, 옥탄올/물 분배계수)

  • Kim, Jeong-Han;Kim, Yong-Hwa;Kim, Kyun
    • Applied Biological Chemistry
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    • v.40 no.1
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    • pp.76-79
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    • 1997
  • Several physicochemical properties such as water solubility, vapor pressure, hydrolysis and octanol/water partition coefficient(Kow) of flupyrazofos, the first organophosphorus insecticide developed in Korea, were measured based on EPA and OECD methods. Water solubility was low showing 0.80 ppm at $25^{\circ}C$ and in hydrolysis study, half-life at $25^{\circ}C$ was 266.5 hr(pH 4.0), 180.0 hr(pH 7.0) and 120.9 hr(pH 9.0) demonstrating instability in alkaline solution. At $40^{\circ}C$ hydrolysis rate was $2{\sim}4$ times higher than that at $25^{\circ}C$. The equation log P=0.673-(1565.4/T) was obtained from vapor pressure experiments at three different temperatures (25, 35, $45^{\circ}C$) and $2.81{\times}10^{-5}$ torr was obtained at $25^{\circ}C$. This value is similar to that of diazinon and 1,000 times lower than that of DDVP suggesting it would not give environmental contamination by volatilization. High log Kow(5.24) was observed and this might result in bioconcentration through food chain. However, its possibility is not likely to be high due to its relatively rapid hydrolysis.

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An Economic Mix Design Methodology for the Development of Concrete Strength at Low Temperature (저온에서의 콘크리트 강도 확보를 위한 경제적 배합 방안)

  • Kim, Sang-Chel;Kim, Yong-Jic;Kim, Young-Jin
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.95-103
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    • 2012
  • Precast concrete method is known to have advantages of minimizing works in the construction, controlling concrete quality easily and saving construction period due to only fabrication work in the construction field, but it needs to apply steam curing to accelerate early concrete strength. In the meanwhile, the oil cost for steam curing has been continuously increased because of political instability in the middle East and international economic shaky. Thus, this study addresses the development of precast/ prestressed concrete which has over 14MPa at 1 day age and specified concrete strength of 40MPa at low temperature, not applying steam curing. Tests were carried out in terms of material characteristics in fresh concrete and compressive strength using 3 types of cement such as Type I, Type III and rapid hardening compound cement. As results of tests, it is found that cements for rapid hardening had disadvantages with respect to slump, slump loss, and air content, but showed higher compressive strength than specified one, especially the highest value when using rapid hardening compound.

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A Research on the Construction Market of the Democratic Republic of the Congo(DRC) and Investment Strategy of Korean Construction Enterprise (콩고민주공화국 건설시장 현황과 진출방안)

  • Lee, Jong-Gwang
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2008.11a
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    • pp.115-118
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    • 2008
  • The promotion of overseas projects by construction enterprises has appeared as a way to overcome the current business difficulties of the Korean construction industry, which largely caused by the slow growth of the domestic market and the intensified competition among construction companies. The government has also shown considerable interests in the strategic approach of promoting construction projects by private companies in natural resource-rich countries, which helps the internationalization of Korean companies and the acouisition of natural resources. In this regard, this research examines the status of the construction market in the Democratic Republic of the Congo(DRC) whose potential economic growth is considered as significant, while exploring the appropriate Investment strategies of Korean construction enterprise. Since little appears to be known about the construction market and economic conditions of the DRC, after a documented review of the development trajectory of the country, a field investigation was preformed in June 2008 for obtaining information on the subjects. This research finds that the road construction is the area to fulfill the several important criteria of implementing construction projects in developing regions, including the safety/reliability for gaining investment profits, the possibility of implementing construction projects on the gradual basis, the possibility of using the facilities after the project completion, and the linkage between payment and the construction stages. In regard to the current economic situation of the DRC and the policies of the DRC government, a package deal approach, which contains the exchange of the infrastructure construction by the Korean companies and the provision of natural resources by the DRC government, is the most feasible method for Korean companies to promote their businesses in the DRC's construction market.

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Effects of Cooking Methods with Different Heat Intensities on Antioxidant Activity and Physicochemical Properties of Garlic (열처리 조리방법이 마늘의 항산화 활성과 이화학적 특성에 미치는 영향)

  • Jo, Hyeri;Surh, Jeonghee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.12
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    • pp.1784-1791
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    • 2016
  • Garlic was subjected to eight different cooking methods (raw, boiling, steaming, microwave cooking, deep-frying, oven-roasting, pan-frying, and pan-roasting) utilized for typical Korean cuisine. Garlic was analyzed for antioxidant activities and physicochemical properties to elucidate effects of cooking. Garlic cooked at higher temperatures showed significantly lower lightness and higher yellowness (P<0.001). In particular, deep-frying and pan-frying resulted in lowest lightness and soluble solid content, indicating that non-enzymatic browning reactions were more facilitated. Compared with raw garlic, all cooked garlic tended to have lower thiosulfinates, presumably due to decomposition into polysulfides and/or leaching into cooking water and oil. Microwave cooking retained organic acids, total reducing capacity, and flavonoids, which can be attributed to low microwave intensity and shorter cooking time under which heat-labile bioactive components might have undergone less decomposition. Cooking significantly increased metal-chelating activity (P<0.001). In addition, oven-roasting and pan-roasting enhanced total reducing capacity and flavonoid content, indicating that thermal treatments increased the extractability of bioactive components from garlic. However, boiling, deep-frying, and pan-frying, in which garlic is in contact directly with a hot cooking medium, reduced antioxidant activities. Deep-frying resulted in largest reduction in DPPH radical scavenging activity of garlic, which correlated well with reduction of total reducing capacity and flavonoid content. The results show that the antioxidant activity of garlic could be affected by cooking method, particularly heat intensity and/or direct contact of the cooking medium.

Absorption Properties of Carbon Dioxide in Aqueous 2-Amino-2-methyl-1-propanol Solution (2-Amino-2-methyl-1-propanol 수용액에 대한 이산화탄소의 흡수특성에 관한 연구)

  • Park, Sang Hyun;Kim, Sung Hyun;Min, Byung Moo
    • Applied Chemistry for Engineering
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    • v.9 no.1
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    • pp.107-114
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    • 1998
  • The solubilities of $CO_2$ in 20wt% and 30wt% aqueous AMP solution were obtained from experiments at 40, 50, 60, 70, $80^{\circ}C$. Using the modified Kent-Eisenberg model, equilibrium constants and correlations were determined from the regression of experimental results of 30wt% aqueous AMP solution. There were good agreements between the predicted $CO_2$ solubilities in 20wt% aqueous AMP solution and experimented values. The prediction was conducted at the condition in the literature and the predicted values calculated from the model and correlations which were obtained from this work agree well with the prediction from Deshmukh-Mather model. Thus, the modified Kent-Eisenberg model and correlated equations suggested by this work, resonably well represent vapor-liquid equilibrium of $CO_2$ with aqueous AMP solution. The calculation of chemical species concentration in the liquid phase was performed uslng equilibrium model and from this calculation, we confirm that good absorption capacity is due to the formation of unstable carbamate. Heat of solution(${\Delta}Hs$) was calculated from the solubility data using the Gibbs-Helmholtz equation.

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Validation of Reference Genes for Quantifying Changes in Physiological Gene Expression in Apple Tree under Cold Stress and Virus Infection (저온과 바이러스 감염에 노출된 사과나무의 생리적 유전자 정량 측정용 유전자들의 발현 분석 및 검증)

  • Yoon, Ju-Yeon;Jeong, Jae-Hoon;Choi, Seung-Kook
    • Research in Plant Disease
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    • v.26 no.3
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    • pp.144-158
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    • 2020
  • Quantitative reverse transcription PCR is used for gene expression analysis as the accurate and sensitive method. To analyze quantification of gene expression changes in apple plants, 10 housekeeping genes (ACT, CKL, EF-1α, GAPDH, MDH, PDI, THFs, UBC, UBC10, and WD40) were evaluated for their stability of expression during infection by Apple stem grooving virus (ASGV) or in cold-stress apple plant buds. Five reference-gene validation programs were used to establish the order of the most stable genes for ASGV as CKL>THFs>GAPDH>ACT, and the least stable genes WD40CKL>UBC10, and the least stable genes were ACT