• Title/Summary/Keyword: equilibrium distribution

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Adsorption Characteristics of Reactive Red 120 by Coal-based Granular Activated Carbon : Isotherm, Kinetic and Thermodynamic Parameters (석탄계 입상활성탄에 의한 Reactive Red 120의 흡착 특성 : 등온선, 동력학 및 열역학 파라미터)

  • Lee, Jong Jib
    • Applied Chemistry for Engineering
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    • v.31 no.2
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    • pp.164-171
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    • 2020
  • Adsorption characteristics of reactive red 120 (RR 120) dye by a coal-based granular activated carbon (CGAC) from an aqueous solution were investigated using the amount of activated carbon, pH, initial concentration, contact time and temperature as adsorption variables. Isotherm equilibrium relationship showed that Langmuir's equation fits better than that of Freundlich's equation. The adsorption mechanism was considered to be superior to the adsorption of monolayer with uniform energy distribution. From the evaluated Langmuir separation coefficients (RL = 0.181~0.644), it was found that this adsorption process belongs to an effective treatment area (RL = 0~1). The adsorption energy determined by Temkin's equation and Dubinin-Radushkevich's equation was E = 15.31~7.12 J/mol and B = 0.223~0.365 kJ/mol, respectively. The adsorption process showed the physical adsorption (E < 20 J/mol and B < 8 kJ/mol). The adsorption kinetics followed the pseudo first order model. The adsorption reaction of RR 120 dye on CGAC was found to increase spontaneously with increasing the temperature because the free energy change decreased with increasing the temperature. The enthalpy change (12.747 kJ/mol) indicated an endothermic reaction. The isosteric heat of adsorption (△Hx = 9.78~24.21 kJ/mol) for the adsorption reaction of RR 120 by CGAC was revealed to be the physical adsorption (△Hx < 80 kJ/mol).

Research Method of Fatty Acids Transfer between Phospholipid Model Membranes (인지질 모델막에서의 지방산 이동에 관한 연구 방법)

  • 임병순;김혜경;김을상
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.4
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    • pp.743-750
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    • 1997
  • Direct measurement of the kinetics of free fatty acid transfer between phospholipid model membrane is technically limited by the rapid nature of the transfer process. Separation of membrane-bound fatty acid by centrifugation has shown that although the equilibrium distribution of free fatty acid is determined by this method, fatty acid transfer occurs too rapidly for accurate kinetic measurements. Recently fluorescence resonance energy transfer(FRET) assay has been developed to examine transfer of fatty acids between membranes. Donor membranes which has fluorescent fatty acid, anthroyloxy fatty acid(AOFA), is mixed with acceptor membranes which has non-interchangeable fluorescent quencher, nitrobenzo-xadiazol(NBD), using stopped flow apparatus. As the fluorescent fatty acids transfer from donor membrane to acceptor membrane, fluorescence intensity would be decreased and the rate and degree of fatty acid transfer can be analyzed. Fatty acid transfer between micelles is more complicated because of bile salt. Therefore in experiments with micelles, fluorescence self quenching assay is used. At high concentrations, a fluorophore tends to quench its own fluorescence causing a reduction in fluorescence intensity. Donor micelles contained self quenching concentrations of fluorophore and acceptor micelles had no fluorophore. Upon mixing of donor and acceptor micelles, the rate of transfer of the fluorophore from the donor to the acceptor was measured by monitoring the release in self quenching when its concentration in donor decreased over time.

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Moisture Content Change of Korean Red Pine Logs During Air Drying: I. Effective Air Drying Days in Major Regions in Korea (소나무 원목의 천연건조 중 함수율 변화: I. 국내 주요지역의 유효천연건조일수 조사)

  • HAN, Yeonjung;EOM, Chang-Deuk;LEE, Sang-Min;PARK, Yonggun
    • Journal of the Korean Wood Science and Technology
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    • v.47 no.6
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    • pp.721-731
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    • 2019
  • Air drying depends on species, density, dimension of wood, the geographical location of the air drying yard, and the meteorological factors of air drying site. If there are four seasons with large difference in temperature and humidity like in Korea, the research of the meteorological factors is required in air drying site. In this study, effective air drying days (EADD) of 24 regions in Korea were calculated by using the average monthly temperature, relative humidity, and wind speed. The EADD in 24 regions in Korea was ranged from 239 days to 291 days, with an average 265 days. This result is 5 days increased compared to the average of EADD calculated using the meteorological factors from 1955 to 1984. The results of multiple regression analysis on the EADD and meteorological factors showed that EADD affected in the order of temperature, relative humidity, and wind speed. As a result of dividing Korea into 4 zones of EADD, the zones of EADD were moved northward compared to previous study due to global warming. As basic data for predicting the moisture content (MC) distribution of Korean red pine logs during air drying conducted in Seoul, the average monthly temperature, relative humidity and wind speed for three years from 2016 to 2018 were presented, and the corresponding changes of the equilibrium MC were analyzed.

Genetic Variation of Pinus densiflora Populations in South Korea Based on ESTP Markers (ESTP 표지를 이용한 국내 소나무 집단의 유전변이)

  • Ahn, Ji Young;Hong, Kyung Nak;Lee, Jei Wan;Hong, Yong Pyo;Kang, Hoduck
    • Korean Journal of Plant Resources
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    • v.28 no.2
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    • pp.279-289
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    • 2015
  • Genetic diversity and genetic differentiation of thirteen Pinus densiflora populations in South Korea were estimated using nine ESTP (Expressed Sequence Tag Polymorphism) markers. The numbers of allele and the effective allele were 2.2 and 1.8, respectively. The percentage of polymorphic loci (P) was 98.8%. The observed and the expected heterozygosity were 0.391 and 0.402, respectively, and the eleven populations except for Ahngang and Gangneung population were under Hardy-Weinberg equilibrium state. The level of genetic differentiation (Wright’s FST = 0.057) was higher than those of isozyme or nSSR markers. We could not find out any relationship between the genetic distance and geographic distribution among populations from cluster analysis. Also, the genetic differentiation between populations was not correlated with the geographic distance (r = 0.017 and P = 0.344 from Mantel test). From the result of FST-outlier analysis to identify a locus under selection, six loci were detected at confidence interval of 99% by the frequentist’s method. However, only three loci (sams2+AluⅠ, sams2+RsaⅠ, PtNCS_p14A9+HaeⅢ) were presumed as outliers by Bayesian method. The sams2+AluⅠ and sams2+RsaⅠlocus were originated from the sams2 gene and seemed to be the loci under balancing selection.

Simulation of Past 6000-Year Climate by Using the Earth System Model of Intermediate Complexity LOVECLIM (중간복잡도 지구시스템모델 LOVECLIM을 이용한 과거 6천년 기후 변화 모의)

  • Jun, Sang-Yoon
    • Atmosphere
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    • v.29 no.1
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    • pp.87-103
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    • 2019
  • This study introduces the overall characteristics of LOVECLIM version 1.3, the earth system model of intermediate complexity (EMIC), including the installation and operation processes by conducting two kinds of past climate simulation. First climate simulation is the equilibrium experiment during the mid-Holocene (6,000 BP), when orbital parameters were different compared to those at present. The overall accuracy of simulated global atmospheric fields by LOVECLIM is relatively lower than that in Coupled Model Intercomparison Project phase 5 (CMIP5) and Paleoclimate modelling Intercomparison Project phase 3 (PMIP3) simulations. However, surface temperature over the globe, the 800 hPa meridional wind over the mid-latitude coastal region, and the 200 hPa zonal wind from LOVECLIM show similar spatial distribution to those multi-model mean of CMIP5/PMIP3 climate models. Second one is the transient climate experiment from mid-Holocene to present. LOVECLIM well captures the major differences in surface temperature between preindustrial and mid-Holocene simulations by CMIP5/PMIP3 multi-model mean, even though it was performed with short integration time (i.e., about four days in a single CPU environment). In this way, although the earth system model of intermediate complexity has a limit due to its relatively low accuracy, it can be a very useful tool in the specific research area such as paleoclimate.

2020 Korean Dietary Reference Intakes for Protein: Estimation of protein requirements and the status of dietary protein intake in the Korean population (2020 단백질 섭취기준: 결핍과 만성질환 예방을 위한 한국인의 단백질 필요량 추정과 섭취현황)

  • Kim, Eunjung;Chung, Sangwon;Hwang, Jin-Taek;Park, Yoon Jung
    • Journal of Nutrition and Health
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    • v.55 no.1
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    • pp.10-20
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    • 2022
  • This article evaluated levels of Estimated Average Requirements (EARs), Reference Nutrient Intakes (RNIs), and Acceptable Macronutrient Distribution Ranges (AMDRs) of protein using the recently revised Dietary Reference Intakes (DRIs) for Koreans (2020). Dietary protein requirements are based on amounts sufficient to satisfy physiological demands to accomplish nitrogen equilibrium. The same principle was applied to estimate EARs and RNIs, for adults in DRIs conducted in 2015 and 2020 in Koreans. EAR was estimated to be 0.73 g/kg body weight/day, according to data (0.66 g/kg body weight/day) obtained using the nitrogen balance method and adjusted by efficiency of protein use (90%). RNI was calculated as EAR increased by an amount equal to twice the standard deviation of an age group so as to cover 97.5% of the group and was found to be 0.91 g/kg body weight/day. For weaned infants, children, and adolescents, growth requirement was added to estimate EAR. In particular, growth requirement was adjusted by efficiency of protein use in the revised EAR, which led to higher EARs for weaned infants, children, and adolescents of both genders as compared with 2015 DRIs. The AMDR for protein was set at 7%-20% of energy intake, which was the same as 2015 DRIs. Current, average protein intake by the Korean population is almost twice times the EAR, which suggests it might be better to increase the minimal margin for AMDR. However, it was not adjusted in this revision due to lack of evidence.

Analysis of High School Students' Conceptual Change in Model-Based Instruction for Blood Circulation (혈액 순환 모형 기반 수업에서 고등학생들의 개념 변화 분석)

  • Kim, Mi-Young;Kim, Heui-Baik
    • Journal of The Korean Association For Science Education
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    • v.27 no.5
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    • pp.379-393
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    • 2007
  • The purpose of this article is to analyze the conceptual change of nine 11th graders after implementing the model-based instruction of blood circulation by multidimensional framework, and to find some implications about teaching strategies for improving conceptual understanding. The model-based instruction consisted of 4 periods: (1) introduction for inducing students' interests using an episode in the science history of blood circulation, (2) vivisectional experiment on rats, (3) visual-linguistic model instruction using the videotape of heartbeat, and (4) modeling activity on the path of blood flow. Based on the data from pre-test, post-test and interviews, we classified students' models on the path of blood flow, and investigated their ontological features and the conceptual status of blood circulation. Most students could describe the path of blood flow and the changes of substances in blood precisely after the instructions. However, the modeling activity were not sufficient to improve students' understanding of the mechanisms of the blood distribution throughout various organs and the material exchanges between blood and tissues. From the interview of 9 students, we acquired informative results about conceptual status elements that were helpful to, preventing from, or not used for students' understanding. It was also found that conceptual status of students depended on the ontological categories into which students' conceptions of blood circulation fell. The results of this study can help design the effective teaching strategy for the understanding of concept of the equilibrium category.

Uncertainty Calculation Algorithm for the Estimation of the Radiochronometry of Nuclear Material (핵물질 연대측정을 위한 불확도 추정 알고리즘 연구)

  • JaeChan Park;TaeHoon Jeon;JungHo Song;MinSu Ju;JinYoung Chung;KiNam Kwon;WooChul Choi;JaeHak Cheong
    • Journal of Radiation Industry
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    • v.17 no.4
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    • pp.345-357
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    • 2023
  • Nuclear forensics has been understood as a mendatory component in the international society for nuclear material control and non-proliferation verification. Radiochronometry of nuclear activities for nuclear forensics are decay series characteristics of nuclear materials and the Bateman equation to estimate when nuclear materials were purified and produced. Radiochronometry values have uncertainty of measurement due to the uncertainty factors in the estimation process. These uncertainties should be calculated using appropriate evaluation methods that are representative of the accuracy and reliability. The IAEA, US, and EU have been researched on radiochronometry and uncertainty of measurement, although the uncertainty calculation method using the Bateman equation is limited by the underestimation of the decay constant and the impossibility of estimating the age of more than one generation, so it is necessary to conduct uncertainty calculation research using computer simulation such as Monte Carlo method. This highlights the need for research using computational simulations, such as the Monte Carlo method, to overcome these limitations. In this study, we have analyzed mathematical models and the LHS (Latin Hypercube Sampling) methods to enhance the reliability of radiochronometry which is to develop an uncertainty algorithm for nuclear material radiochronometry using Bateman Equation. We analyzed the LHS method, which can obtain effective statistical results with a small number of samples, and applied it to algorithms that are Monte Carlo methods for uncertainty calculation by computer simulation. This was implemented through the MATLAB computational software. The uncertainty calculation model using mathematical models demonstrated characteristics based on the relationship between sensitivity coefficients and radiative equilibrium. Computational simulation random sampling showed characteristics dependent on random sampling methods, sampling iteration counts, and the probability distribution of uncertainty factors. For validation, we compared models from various international organizations, mathematical models, and the Monte Carlo method. The developed algorithm was found to perform calculations at an equivalent level of accuracy compared to overseas institutions and mathematical model-based methods. To enhance usability, future research and comparisons·validations need to incorporate more complex decay chains and non-homogeneous conditions. The results of this study can serve as foundational technology in the nuclear forensics field, providing tools for the identification of signature nuclides and aiding in the research, development, comparison, and validation of related technologies.

The Impact of Market Environments on Optimal Channel Strategy Involving an Internet Channel: A Game Theoretic Approach (시장 환경이 인터넷 경로를 포함한 다중 경로 관리에 미치는 영향에 관한 연구: 게임 이론적 접근방법)

  • Yoo, Weon-Sang
    • Journal of Distribution Research
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    • v.16 no.2
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    • pp.119-138
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    • 2011
  • Internet commerce has been growing at a rapid pace for the last decade. Many firms try to reach wider consumer markets by adding the Internet channel to the existing traditional channels. Despite the various benefits of the Internet channel, a significant number of firms failed in managing the new type of channel. Previous studies could not cleary explain these conflicting results associated with the Internet channel. One of the major reasons is most of the previous studies conducted analyses under a specific market condition and claimed that as the impact of Internet channel introduction. Therefore, their results are strongly influenced by the specific market settings. However, firms face various market conditions in the real worlddensity and disutility of using the Internet. The purpose of this study is to investigate the impact of various market environments on a firm's optimal channel strategy by employing a flexible game theory model. We capture various market conditions with consumer density and disutility of using the Internet.

    shows the channel structures analyzed in this study. Before the Internet channel is introduced, a monopoly manufacturer sells its products through an independent physical store. From this structure, the manufacturer could introduce its own Internet channel (MI). The independent physical store could also introduce its own Internet channel and coordinate it with the existing physical store (RI). An independent Internet retailer such as Amazon could enter this market (II). In this case, two types of independent retailers compete with each other. In this model, consumers are uniformly distributed on the two dimensional space. Consumer heterogeneity is captured by a consumer's geographical location (ci) and his disutility of using the Internet channel (${\delta}_{N_i}$).
    shows various market conditions captured by the two consumer heterogeneities.
    (a) illustrates a market with symmetric consumer distributions. The model captures explicitly the asymmetric distributions of consumer disutility in a market as well. In a market like that is represented in
    (c), the average consumer disutility of using an Internet store is relatively smaller than that of using a physical store. For example, this case represents the market in which 1) the product is suitable for Internet transactions (e.g., books) or 2) the level of E-Commerce readiness is high such as in Denmark or Finland. On the other hand, the average consumer disutility when using an Internet store is relatively greater than that of using a physical store in a market like (b). Countries like Ukraine and Bulgaria, or the market for "experience goods" such as shoes, could be examples of this market condition. summarizes the various scenarios of consumer distributions analyzed in this study. The range for disutility of using the Internet (${\delta}_{N_i}$) is held constant, while the range of consumer distribution (${\chi}_i$) varies from -25 to 25, from -50 to 50, from -100 to 100, from -150 to 150, and from -200 to 200.
    summarizes the analysis results. As the average travel cost in a market decreases while the average disutility of Internet use remains the same, average retail price, total quantity sold, physical store profit, monopoly manufacturer profit, and thus, total channel profit increase. On the other hand, the quantity sold through the Internet and the profit of the Internet store decrease with a decreasing average travel cost relative to the average disutility of Internet use. We find that a channel that has an advantage over the other kind of channel serves a larger portion of the market. In a market with a high average travel cost, in which the Internet store has a relative advantage over the physical store, for example, the Internet store becomes a mass-retailer serving a larger portion of the market. This result implies that the Internet becomes a more significant distribution channel in those markets characterized by greater geographical dispersion of buyers, or as consumers become more proficient in Internet usage. The results indicate that the degree of price discrimination also varies depending on the distribution of consumer disutility in a market. The manufacturer in a market in which the average travel cost is higher than the average disutility of using the Internet has a stronger incentive for price discrimination than the manufacturer in a market where the average travel cost is relatively lower. We also find that the manufacturer has a stronger incentive to maintain a high price level when the average travel cost in a market is relatively low. Additionally, the retail competition effect due to Internet channel introduction strengthens as average travel cost in a market decreases. This result indicates that a manufacturer's channel power relative to that of the independent physical retailer becomes stronger with a decreasing average travel cost. This implication is counter-intuitive, because it is widely believed that the negative impact of Internet channel introduction on a competing physical retailer is more significant in a market like Russia, where consumers are more geographically dispersed, than in a market like Hong Kong, that has a condensed geographic distribution of consumers.
    illustrates how this happens. When mangers consider the overall impact of the Internet channel, however, they should consider not only channel power, but also sales volume. When both are considered, the introduction of the Internet channel is revealed as more harmful to a physical retailer in Russia than one in Hong Kong, because the sales volume decrease for a physical store due to Internet channel competition is much greater in Russia than in Hong Kong. The results show that manufacturer is always better off with any type of Internet store introduction. The independent physical store benefits from opening its own Internet store when the average travel cost is higher relative to the disutility of using the Internet. Under an opposite market condition, however, the independent physical retailer could be worse off when it opens its own Internet outlet and coordinates both outlets (RI). This is because the low average travel cost significantly reduces the channel power of the independent physical retailer, further aggravating the already weak channel power caused by myopic inter-channel price coordination. The results implies that channel members and policy makers should explicitly consider the factors determining the relative distributions of both kinds of consumer disutility, when they make a channel decision involving an Internet channel. These factors include the suitability of a product for Internet shopping, the level of E-Commerce readiness of a market, and the degree of geographic dispersion of consumers in a market. Despite the academic contributions and managerial implications, this study is limited in the following ways. First, a series of numerical analyses were conducted to derive equilibrium solutions due to the complex forms of demand functions. In the process, we set up V=100, ${\lambda}$=1, and ${\beta}$=0.01. Future research may change this parameter value set to check the generalizability of this study. Second, the five different scenarios for market conditions were analyzed. Future research could try different sets of parameter ranges. Finally, the model setting allows only one monopoly manufacturer in the market. Accommodating competing multiple manufacturers (brands) would generate more realistic results.

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  • Distributions of 137Cs and 90Sr in the Soil of Uljin, South Korea (울진토양에서의 137Cs 및 90Sr 분포)

    • Song, JiYeon;Kim, Wan;Maeng, Seongjin;Lee, Sang Hoon
      • Journal of Radiation Protection and Research
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      • v.41 no.1
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      • pp.49-55
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      • 2016
    • Background: For the purpose of baseline data collection and enhancement of environmental monitoring the distribution studies of $^{137}Cs$ and $^{90}Sr$ in the soil of Uljin province was performed and the relation between surface soil activities and soil properties (pH, TOC and median of the surface soil) was analyzed. Materials and Methods: For 14 spots within 10 km from the NPP surface soil samples were collected and soils for depth profile were sampled for 3 spots in April 2011. Using ${\gamma}$-ray spectrometry with HPGe detector, the concentrations of $^{137}Cs$ were determined and the concentrations of $^{90}Sr$ were measured by counting ${\beta}$-activity of $^{90}Y$ (in equilibrium with $^{90}Sr$) in a gas flow proportional counter. Results and Discussion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ were $<0.479-39.6Bq{\cdot}(kg-dry)^{-1}$ (avg. $7.51Bq{\cdot}(kg-dry)^{-1}$) and $0.209-1.85Bq{\cdot}(kg-dry)^{-1}$ (avg. $0.74Bq{\cdot}(kg-dry)^{-1}$) which were similar to the reported values from other regions in Korea. The activity ratio of $^{137}Cs$ to $^{90}Sr$ in surface soils was around 9.67, which is much bigger than the initial value of 1.75 for worldwide fallouts because of faster downward movement of $^{90}Sr$ after fallout than that of $^{137}Cs$. For depth profile studies soils were collected down to 40 cm depth for the locations of Deokgu, Hujeong and Maehwa. The $^{137}Cs$ concentration distribution of the first two showed maximum values at top soils and decreased rapidly in exponential manner, while $^{90}Sr$ showed two local maximum values for soils near top and about 30 cm depth. Through linear fittings between the $^{137}Cs$ and $^{90}Sr$ concentrations of surface soil and pH, TOC and median of the surface soil, the only probable relationship obtained was between $^{137}Cs$ and TOC (determination coefficient $R^2=0.6$). Conclusion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ in Uljin were similar to the reported values from other regions in Korea. The only probable relationship obtained between activities and soil properties was between $^{137}Cs$ and TOC.


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