• Title/Summary/Keyword: 재료선정

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Electrochemical Decontamination of Metallic Wastes Contaminated with Uranium Compounds (우라늄화합물로 오염된 금속폐기물의 전해제염)

  • 양영미;최왕규;오원진;유승곤
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.1 no.1
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    • pp.11-23
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    • 2003
  • A study on the electrolytic dissolution of SUS-304 and Inconel-600 specimen was carried out in neutral salt electrolyte to evaluate the applicability of electrochemical decontamination process for recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant in Korea. Although the best electrolytic dissolution performance for the specimens was observed in a Na2s04 electrolyte, a NaNO$_3$ neutral salt electrolyte, in which about 30% for SUS-304 and the same for Inconel-600 in the weight loss was shown in comparison with that in a Na$_2$SO$_4$ solution, was selected as an electrolyte for the electrochemical decontamination of metallic wastes with the consideration on the surface of system components contacted with nitric acid and the compatibility with lagoon wastes generated during the facility operation. The effects of current density, electrolytic dissolution time, and concentration of NaNO$_3$ on the electrolytic dissolution of the specimens were investigated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as UO$_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion facility were performed in 1M NaNO$_3$ solution with the current density or In mA/$\textrm{cm}^2$. it was verified that the electrochemical decontamination of the metallic wastes contaminated uranium compounds was quite successful in a NaNO$_3$ neutral salt electrolyte by reducing $\alpha$ and $\beta$ radioactivities below the level of self disposal within 10 minutes regardless of the type of contaminants and the degree of contamination.

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Differences among Major Rice Cultivars in Tensile Strength and Shattering of Grains during Ripening and Field Loss of Grains (벼알의 인장강도 및 탈립성의 등숙중 변화와 품종간 차이 및 포장손실과의 관계)

  • Y. W. Kwon;J. C. Shin;C. J. Chung
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.27 no.1
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    • pp.1-10
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    • 1982
  • Degree of grain shattering which is of varietal character is an important determinant for the magnitude of field loss of grains during harvest and threshing. Seven Indica \times Japonica progeny varieties and four Japonica varieties were subjected to measurements of tensile strength of grains, degree of grain shattering when panicles were dropped at 1.5m above concrete floor, and moisture content of grains (wet basis) during a period 35 to 63 days after heading. In addition, two varieties were tested for the relation of tensile strength of grains to the magnitude of field loss of grains in actual binder harvest. The 11 varieties differed conspicuously in tensile strength of grains and the degree of grain shattering: the weakest average tensile strength of grains of a variety was about 90g and the strongest about 250g with varying standard deviation of 30 to 60g. Three Indica \times Japonica varieties and one Japonica variety shattered I to 30% of the grains under the falling test. The threshold tensile strength of grains allowing grain shattering was estimated to be 180g on average for a sampling unit of 10 panicles, but only the grains having tensile strength weaker than 98g within the samples shattered. A decrease in average tensile strength by 10g below the threshold value corresponded to an increase of 3 to 5% in grain shattering. Most varieties did not change appreciably the tensile strength of grains and degree of grain shattering with delay in time of harvest and showed a negative correlation between the tensile strength and the moisture content of grains. The average tensile strength of grains was negatively correlated linearly with field loss in binder harvest. The average tensile strength for zero field loss in binder harvest was estimated to be 174g and a decrease in the average tensile strength by 10g corresponded to an increase of 40kg per hectare in field loss of grains. Instead of the average tensile strength of grains, the percentage of grains having tensile strength weaker than 100g is recommended as a criterion for the estimation of field loss of grains during harvesting operations as well as a basis of variety classification for grain shattering, since the standard deviation of tensile strength of grains varies much with variety and time of harvest, and individual grains having tensile strength stronger than 98 did not shatter practically.

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Trends in Rapid Detection Methods for Marine Organism-derived Toxins (해양 생물 유래 독소의 나노 기술 기반 신속 진단법 개발 동향)

  • Park, Chan Yeong;Kweon, So Yeon;Moon, Sunhee;Kim, Min Woo;Ha, Sang-Do;Park, Jong Pil;Park, Tae Jung
    • Journal of Food Hygiene and Safety
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    • v.35 no.4
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    • pp.291-303
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    • 2020
  • Marine organism-derived toxins have negative effects not only on human health but also in aquaculture, fisheries, and marine ecosystems. However, traditional analytical methods are insufficient in preventing this threat. In this paper, we reviewed new rapid methods of toxin detection, which have been improved by adopting diverse types of nanomaterials and technologies. Moreover, we herein describe the main strategies for toxin detection and their related sensing performance. Notably, to popularize and commercialize these newly developed technologies, simplifying the process of pre-treating real samples real samples is very important. As part of these efforts, numerous studies have reported pretreatment methods based on the antibody-immobilized magnetic nanoparticles, and some cases have applied nanoparticles to enhance the sensing performance by utilizing the intrinsic catalytic activity. Furthermore, some reports have introduced fluorescent nanoparticles, such as quantum dots, to represent the lower detection limits of conventional enzyme-based colorimetric methods and lateral flow assays. Some studies using electrochemical measurements based on aptamer-nanoparticle complexes have also been announced. In addition, as the response to new toxins generated by changes in the marine environment is still lacking, further research on diagnostic and detection is also greatly needed for these kinds of marine toxins and their derivatives.

가족과 함께하는 창의성 경진대회 평가연구

  • 송규운;황동주;윤정진
    • Journal of Gifted/Talented Education
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    • v.11 no.2
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    • pp.127-150
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    • 2001
  • The upcoming century is a knowledge based society which did not exist before which requires creative ability to solve problems. Therefore, it is necessary to Provide a creative program of problem solution in order to match this global trend The creativity of problem solution means the ability to solve a problem using previous ideas in an advanced way or develop new ideas. Creative education is especially important for infants. Because the young mind is where fresh ideas preside and can frame-work the early stage of life like a blank sheet of paper. The Infant-Early Child Creative Development Institute. as an adhesive institute at Yeungjin College, develops various programs that integrate methods which match current trend in this era and also start the Creative Promotion Test with 2,000 Families for the expansion of creative education from the baseline as an alternative method. The infants tested in the creative test will find ways of problem solution through animation beam projects for their given situation and also discuss the problems with their family members. Through these processes the infant and family members will complete the creative structures to solve the problems using limited materials given by the institute, and the final product will be evaluated as objective results. The final evaluation of the test will also be considered the teamwork of family cooperation and the attitudes of participants as well as the product of problem solution. The criterion of the evaluation is to be considered both a creative way of thinking and creative attitudes. Because the score counts were conducted manually it delayed the selection of awarded students who took the test. Also, we found that some parents have difficulty in accessing information to find the score through homepage from the computer. this Problem might be corrected in the future plan. Like Freud's saying, if human character and exploring attitudes during the early stage of a child, a person's creativity is composed their infant period as their basic foundation. Therefore, the family wh first environment the infant encounters will be treated as a prima when making basic structure. From this viewpoint, this creative test work as a festival of creativity fare with 2,000 families.

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The Development and Acceptance of Knowledge Information in Garden of Joseon Dynasty - Focusing on the Garden and Flowering Books Compiled from the 15th and 19th Centuries - (조선시대 정원의 지식정보 전개와 수용 - 15~19세기 편찬된 정원 및 화훼 관련서적을 중심으로 -)

  • Kim, Dong-Hyun;Lee, Won-Ho
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.38 no.1
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    • pp.10-20
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    • 2020
  • This study aims to analyze the developed characteristics of the knowledge and information of gardens through garden or flowering plant books compiled in the 15th and 19th centuries of Joseon Dynasty. Diachronically analysis of the garden or flowering plant books classified the characteristics in which knowledge and information about gardens are developed by the period, and looked at the factors. The results are as follows; First, the relationship between the authors who compiled the garden or flowering plant books had similar characteristics to the genealogy of Realist School of Confucianism(實學) in the Joseon Dynasty. Kang, Hee-An's practical features influenced later realist school of confucianism scholars. Lee, Su-Gwang has accumulated knowledge of the garden through his experience of traveling the diplomatic envoy to China. Since then, Hong Man-sun's ideology has been related to Charles, a member of the Southerners. Seo Yu-gu was also able to accept Realist School of Confucianism in an integrated way through the Jungnong school's theory and interaction with the Jungsang school. Ryu, Jung-Lim's relationship with the Jungnong school emerged as he added to the 『Jeungbosanrimgyeongje(增補山林經濟)』. Second, the 『Yanghwasorok(養花小錄)』, 『Jibongyuseol(芝峯類說)』 「Hwuimok(卉木)」, 『Hangjeongrok(閑情錄)』, 『Sanrimgyeongje(山林經濟)』 「Yanghwa(養花)」, 『Jeungbosanrimgyeongje(增補山林經濟)』 「Yanghwa(養花)」, 『Hwaamsurok(花庵隨錄)』 and 『Imwongyeongjeji(林園經濟志)』 「Yewonji(藝畹志)」 contain garden plant characteristics, cultivation methods, and management methods. The 『Imwongyeongjeji(林園經濟志)』 「Seomyongji(贍用志)」, 「Iunji(怡雲志)」, 「Sangtaekji(相宅志)」 contain details on the location selection of gardens, the layout of facilities, how to create them and materials. The description of these garden or flowering plant books was found to be the most common introduction with 55 percent, followed by methodologies(42.8%), the Lichi Theory(理氣論, 15.5%), the classification(12.4%), and the convention(1.9%). Third, based on the importance of knowledge and information on gardens, the garden or flowering plant books related to the period were classified as early period, including 『Yanghwasorok(養花小錄)』, 『Jibongyuseol(芝峯類說)』 which were compiled before the 17th century. The 18th-century compiled 『Sanrimgyeongje(山林經濟)』 and 『Jeungbosanrimgyeongje(增補山林經濟)』 were classified as middle period, and the 19th-century compilation of 『Imwongyeongjeji(林園經濟志)』 was classified as late period. The garden or flowering plant books were cited the contents of ancient Chinese books, the author's experiences and opinions contained in the preceding period in later garden books. And the reinforcement of garden knowledge was made to reflect the agricultural technology and expertise developed at the time of writing. Fourth, based on analysis of the development and acceptance of knowledge information in garden by period, In the early period was dealing with floriculture as a way to explore the logic of things. Later, in the 18th century, a vast influx of garden knowledge information came from China. Among scholars, they secured justification for garden creation as part of various knowledge-seeking activities, which expanded their expertise in gardens. In response to the trend of gardening in the 19th century, professional books were written based on knowledge and information on gardens that were collected in the past, and systems were established such as the collection and management of garden plants, construction methods, enjoying methods, and self-realization.

Comparison of Germination Power, Germination Speed, and Germination Peak Time among Five Festuca Species (훼스큐 속 잔디 5종의 발아력, 발아세 및 발아 피크 기간 비교)

  • Kim, Kyoung-Nam
    • Weed & Turfgrass Science
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    • v.4 no.4
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    • pp.330-337
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    • 2015
  • Research was conducted to investigate germination and establishment characteristics of five fescue species. Alternative conditions of 8-hr light at $25^{\circ}C$ and 16-hr dark at $15^{\circ}C$ were applied. Significant differences were observed in seed germination power, germination speed and germination peak time. Germination power was 62.25% in CRF 'Audubon' to 96.75% in TF 'Olympic Gold'. It was greater with TF over FF, being TF > HF > SF > CF > CRF. Germination speed, measured as days to seed germination of 50% through 80%, was fastest with TF, medium with CF and HF, and slowest with CRF and SF, being TF > CF, HF > CRF, SF. Germination peak time was much faster with TF over FF. It ranged from 0.94 to 1.47 days with TF. But it varied with 2.80 to 12.36 days among FF species. The peak time was longer in order of HF, SF < CF < CRF. Considering germination power, germination speed and germination peak time, TF 'Arid III' was the best cultivar under alternative conditions, while CRF 'Audubon' the poorest. Overall establishment characteristics among Festuca species were even better with TF over FF in order of TF > CF, HF > SF > CRF.

Finite element analysis of peri-implant bone stress influenced by cervical module configuration of endosseous implant (임플란트 경부형상이 주위골 응력에 미치는 영향에 관한 유한요소법적 분석)

  • Chung, Jae-Min;Jo, Kwang-Heon;Lee, Cheong-Hee;Yu, Won-Jae;Lee, Kyu-Bok
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.4
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    • pp.394-405
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    • 2009
  • Statement of problem: Crestal bone loss, a common problem associated with dental implant, has been attributed to excessive bone stresses. Design of implant's transgingival (TG) part may affect the crestal bone stresses. Purpose: To investigate if concavely designed geometry at a dental implant's TG part reduces peri-implant bone stresses. Material and methods: A total of five differently configured TG parts were compared. Base model was the ITI one piece implant (Straumann, Waldenburg, Switzerland) characterized by straight TG part. Other 4 experimental models, i.e. Model-1 to Model-4, were designed to have concave TG part. Finite element analyses were carried out using an axisymmetric assumption. A vertical load of 50 N or an oblique load of 50 N acting at $30^{\circ}$ with the implant's long axis was applied. For a systematic stress comparison, a total of 19 reference points were defined on nodal points around the implant. The peak crestal bone stress acting at the intersection of implant and crestal bone was estimated using regression analysis from the stress results obtained at 5 reference points defined along the mid plane of the crestal bone. Results: Base Model with straight configuration at the transgingival part created highest stresses on the crestal bone. Stress level was reduced when concavity was imposed. The greater the concavity and the closer the concavity to the crestal bone level, the less the crestal stresses. Conclusion: The transgingival part of dental implant affect the crestal bone stress. And that concavely designed one may be used to reduce bone stress.

Changes of Major Components and Microorganisms during the Fermentation of Korean Ordinary Kochujang (한국재래식(韓國在來式)고추장숙성중(熟成中)의 주요성분(主要成分) 및 미생물(微生物)의 변화(變化))

  • Ahn, Cheol-Woo;Sung, Nack-Kie
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.16 no.3
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    • pp.35-39
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    • 1987
  • The present study was attempted to obtain the basic data concerning a reasonable preparing method and the optimum fermentation conditions of Kochujang (Red pepper paste). To establish the standard qualify of Kochujang, changes of the chemical composition and the numbers of bacteria and feasts in Kochujang during fermentation were observed. Moisture, salts and crude ash contents of Kochujang were not changed significantly during fermentation. Titrable acidity and amino nitrogen gradually increased with the time-passed, whereas crude fat gradually decreased with the time-elapsed. And reducing sugar and total nitrogen increased until 40 days, but slightly decreased after this period. The numbers of bacteria and yeasts in the ingrients for the preparation of Kochujang were $3.9{\times}10^7/g$, $1.5{\times}10^3/g$ in red pepper powder, $7.6{\times}10^4/g$, $2.8{\times}10^2/g$ in salts. respectively, but those of sugar and malt were not more than 100/g. Microbial counts in Kochujang during fermentation increased until 40 days, but those are gradually decreased after that.

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Total Polyphenol Contents and Antioxidant Activities of Methanol Extracts from Vegetables produced in Ullung Island (울릉도산 산채류 추출물의 총 폴리페놀 함량 및 항산화 활성)

  • Lee, Syng-Ook;Lee, Hyo-Jung;Yu, Mi-Hee;Im, Hyo-Gwon;Lee, In-Seon
    • Korean Journal of Food Science and Technology
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    • v.37 no.2
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    • pp.233-240
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    • 2005
  • To discover new functional materials using edible plants, antioxidant activities of methanol extracts from various parts of seven wild vegetables were investigated in vitro. Total polyphenol contents, determined by Folin-Denis method, varied from 16.74 to $130.22{\mu}g/mg$. Radical-scavenging activities of methanol extracts were examined using ${\alpha},\;{\alpha}-diphenyl-{\beta}-pirrylhydrazyl$ (DPPH) radicals and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assay. Inhibition effects on peroxidation of linoleic acid determined by ferric thiocyanate (FTC) method and on oxidative degradation of 2-deoxy-D-ribose in Fenton-type reaction system were dose-dependent. Athyrium acutipinulum Kodama (leaf and rood), Achyranthes japonica (Miq.) Nakai (seed), and Solidago virga-aurea var. gigantea Nakai (root) showed relatively high antioxidant activities in various systems.

THE INFLUENCE OF CAVITY CONFIGURATION ON THE MICROTENSILE BOND STRENGTH BETWEEN COMPOSITE RESIN AND DENTIN (와동의 형태가 상아질과 복합레진 사이의 미세인장결합강도에 미치는 영향)

  • Kim, Ye-Mi;Park, Jeong-Won;Lee, Chan-Young;Song, Yoon-Jung;Seo, Deok-Kyu;Roh, Byoung-Duck
    • Restorative Dentistry and Endodontics
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    • v.33 no.5
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    • pp.472-480
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    • 2008
  • This study was conducted to evaluate the influence of the C-factor on the bond strength of a 6th generation self-etching system by measuring the microtensile bond strength of four types of restorations classified by different C-factors with an identical depth of dentin. Eighty human molars were divided into four experimental groups, each of which had a C-factor of 0.25, 2, 3 or 4. Each group was then further divided into four subgroups based on the adhesive and composite resin used. The adhesives used for this study were AQ Bond Plus (Sun Medical, Japan) and XenoIII (DENTSPLY, Germany). And composite resins used were fantasists (Sun Medical, Japan) and Ceram-X mono (DENTSPLY, Germany). The results were then analyzed using one-way ANOVA, a Tukey's test, and a Pearson's correlation test and were as follows. 1. There was no significant difference among C-factor groups with the exception of groups of Xeno III and Ceram-X mono (p<0.05). 2. There was no significant difference between any of the adhesives and composite resins in groups with C-factor 0.25, 2 and 4. 3. There was no correlation between the change in C-factor and microtensile bond strength in the Fantasista groups. It was concluded that the C-factor of cavities does not have a significant effect on the microtensile bond strength of the restorations when cavities of the same depth of dentin are restored using composite resin in conjunction with the 6th generation self-etching system.