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The Effect of the Sn contents on Rapidly Solidified Ag-X%Zn Electric Contact Materials (급속응고한 Ag-X%Zn계 전기접점재료에 미치는 Sn함량의 영향)

  • Kim, Jong-Kyu;Jang, Dae-Jung;Ju, Kwang-Il;Lee, Eun-Ho;Um, Seung-Yeul;Nam, Tae-Woon
    • Journal of Korea Foundry Society
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    • v.28 no.4
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    • pp.184-189
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    • 2008
  • Ag-Cd alloy has been widely used as an electrical contact material, since Ag-Cd alloy has a good wear resistance and stable contact resistance. But nowadays Ag-Cd alloy is not considered as electrical contact material any more due to detrimental effect on environments. Currently, active researches are being performed on ($Ag-SnO_2$ and $Ag-SnO_{2}-In_{2}O_{3}$) as an alternative solution which can fix the remaining environmental problems. However, $In_{2}O_{3}$ is relatively expensive and Ag-Sn alloy has low wear resistance. Our recent research results show that Ag-X%Zn-Y%Sn has similar physical and chemical properties. In the present study, so we tried to change and to optimize the Zn oxide content to over 6 wt% and Sn oxide content with 0.5, 1.0, 1.5 wt%. Results obtained from the experiments on the Ag-X%ZnO-Y%$SnO_2$ are discussed.

Syntactic Ambiguities and Their Resolution in Prosody between Sendai dialect of Japanese and Ankara dialect of Turkish (일본 센다이 방언과 터키 앙카라 방언의 운율에 나타나는 통사적 애매성 해소에 관한 연구)

  • Choi, Young-Sook
    • Speech Sciences
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    • v.10 no.3
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    • pp.175-185
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    • 2003
  • Japanese and Turkish are syntactically similar to each other, and there are syntactic structures that become ambiguous in terms of NP's and VP's modified by adjectives and adverbs, respectively. The prosody can play a crucial role in differentiating ambiguous sentences to correctly reflect their intended syntactic structures. In what way do the speakers of Sendai dialect of Japanese and Turkish use prosodic elements to differentiate syntactic ambiguities? Acoustic measurements were made of utterances of ambiguous sentences in Japanese and Turkish to observe prosodic strategies for disambiguation. Materials were sentences of the type ADV-VP1-NP-VP2, ADV-NP1-NP2-VP2, where the ambiguity lies in locative adverbial modification, ADV modifying either VP1 or VP2. For this construction the Japanese and Turkish creates the same ambiguities. In this paper, I look at duration, F0, and pause as observed in their speech and see how each language uses three prosodic elements in disambiguation. The results show that both speakers of Sendai dialect in Japan and those of Ankara dialect in Turky use lengthening of the syllable and/or pause before the boundary.

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Modulation of the Metal(loid) Specificity of Whole-Cell Bioreporters by Genetic Engineering of ZntR Metal-Binding Loops

  • Kim, Hyojin;Jang, Geupil;Kim, Bong-Gyu;Yoon, Youngdae
    • Journal of Microbiology and Biotechnology
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    • v.30 no.5
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    • pp.681-688
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    • 2020
  • Bacterial cell-based biosensors, or whole-cell bioreporters (WCBs), are an alternative tool for the quantification of hazardous materials. Most WCBs share similar working mechanisms. In brief, the recognition of a target by sensing domains induces a biological event, such as changes in protein conformation or gene expression, providing a basis for quantification. WCBs targeting heavy metal(loid)s employ metalloregulators as sensing domains and control the expression of genes in the presence of target metal(loid) ions, but the diversity of targets, specificity, and sensitivity of these WCBs are limited. In this study, we genetically engineered the metal-binding loop (MBL) of ZntR, which controls the znt-operon in Escherichia coli. In the MBL of ZntR, three Cys sites interact with metal ions. Based on the crystal structure of ZntR, MBL sequences were modified by site-directed mutagenesis. As a result, the metal-sensing properties of WCBs differed depending on amino acid sequences and the new selectivity to Cr or Pb was observed. Although there is room for improvement, our results support the use of currently available WCBs as a platform to generate new WCBs to target other environmental pollutants including metal(loid)s.

A Study on Evaluation of Korean Collection of North America: Focused on the A University (북미 대학의 한국학 장서 평가에 관한 연구: A 대학을 중심으로)

  • Oh, Kyung-Mook
    • Journal of the Korean Society for information Management
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    • v.25 no.4
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    • pp.269-281
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    • 2008
  • This paper evaluated the collection development of the Korean collection at the A university over the several decade. Compared against the ACRL standard Formula A, the result demonstrated that the Korean library collection is still needed to increase Korean collection to support Korean-related program and Korean community in the area. When we share western language materials in the library as the same area studies resources, we can evaluate Korean studies collection as Level B. Comparison with similar institutions (ARL comparisons) shows that the collection is the middle among 15 universities which provide Korean programs. The situation for Korean resources at the A university is needed to get more support from Korean institutes and Korean societies to keep up with the Korean collection for academics and regional community users as well.

A Study on the Improvements of Administrative Rules of Korea Foreign Trade Act (대외무역법 행정규칙의 개편방향에 관한 연구)

  • Park, Kwang So
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.63
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    • pp.185-207
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    • 2014
  • There are over 20 administrative rules related to Korea Foreign Trade Act including Export and Import Notification, Consolidated Notification, Notification for Strategic Materials and so on. The purpose of this research proposes to reform some administrative rules related to Korea Foreign Trade Act. First, the administrative rules are a little many and hidden in part, so the effort need for simplification and publication. Especially Export and Import Notification is no need more, and some articles can be transfer to the similar notification. Second, the prohibited or regulated items are only 135, and the reason is cooperation to world trade policy and Korea trade purpose. The item number of trade limitation are decreased sharply compare to several decades, but we still effort to decrease. Third, There are 2 tracks trade regulation both Korea Foreign Trade Act and 57 specific acts. The number of trade limitation item is over 5,000, so it is impossible to control by Consolidated Notification. The role of Consolidated Notification is the just guides for Export and Import, so trader has to use the specific trade-related law.

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Innovative Modeling of Explosive Shock Wave Assisted Drug Delivery (고에너지물질에 의한 약물 전달 시스템 연구)

  • Yoh, Jai-Ick;Kim, Ki-Hong;Lee, Kyung-Cheol;Lee, Hyun-Hee;Park, Kyoung-Jin
    • 한국연소학회:학술대회논문집
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    • 2006.04a
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    • pp.213-217
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    • 2006
  • Recent advances in energetic materials modeling and high-resolution hydrocode simulation enable enhanced computational analysis of bio-medical treatments that utilize high-pressure shock waves. Of particular interest is in designing devices that use such technology in medical treatments. For example, the generated micro shock waves with peak pressure on orders of 10 GPa can be used for treatments such as kidney stone removal, trans-dermal micro-particle delivery. and cancer cell removal. In this work, we present a new computational methodology for applying the high explosive dynamics to bio-medical treatments by making use of high pressure shock physics and multi-material wave interactions. The preliminary calculations conducted by the in-house code, GIBBS2D, captures various features that are observed from the actual experiments under the similar test conditions. We expect to gain novel insights in applying explosive shock wave physics to the bio-medical science involving drug injection. Our forthcoming papers will illustrate the quantitative comparison of the modeled results against the experimental data.

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Exploration of Engineering Professors' Teaching Orientations toward Engineering Courses (공과대학 교수학습의 질적 향상을 위한 공학 교수자의 교수지향 탐색)

  • Jang, Jiyoung;Lee, Hyunju
    • Journal of Engineering Education Research
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    • v.19 no.3
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    • pp.23-34
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    • 2016
  • Teaching orientations represent teachers' general way of conceptualizing their teaching. The orientations are regarded as a very important factor in developing teachers' pedagogical content knowledge because they often guide their instructional decisions such as the selection of contents and teaching strategies, the use of curricula materials, and the evaluation of learning. Thus, understanding teachers' orientations can provide meaningful suggestions to understand their instructional approaches and furthermore to enhance the quality of engineering education in college. The research question for this present study was what kinds of teaching orientations engineering professors possessed in teaching engineering courses and how the orientations were represented in their teaching. Six engineering professors, particularly interested in instructional approaches, participated in the research. The data sources included in-depth interviews with individual professors, classroom observations with field notes, and related documents. In results, four teaching orientations toward engineering courses were identified: 1) expert knowledge in engineering, 2) engineering practice, 3) social practice, and 4) interdisciplinary design. Individual professors had between one to three different teaching orientations. Even though the professors had similar orientations but their instructional strategies somewhat varied based on the disciplines.

Garlic-induced Hematologic Effects in Small dogs (소형견에서 마늘투여가 혈액상에 미치는 영향)

  • 장우석;김홍태;진태원;장혜숙;정규식;박승춘;오태호;송재찬;김영홍
    • Journal of Veterinary Clinics
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    • v.18 no.4
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    • pp.341-344
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    • 2001
  • It is well-known that onion and garlic of Allium family have been cultivated for major food since ancient times. Especially garlic is known for containing protective materials against cardiovascular disease, neoplasm and cancer, and decreasing cholesterol value. Hemolytic anemia was first reported by Goldsmith in onion-fed cattle in 1909. Subsequently, similar effects have been reported in cattle, horses, sheep, dogs and cats. This toxic effect has been attributed to n-propyl disulfide which causes oxidant damage to erythrocyte cell membrane. There are few reports on overconsumption of garlic. Kim et al. reported in 1999 that 45% of Jindo dogs in korea have erythrocytes characterized by high Na-K-ATPase activity with high K and low Na concentrations (HK) which easily results in hemolytic anemia. The purpose of present report is to determine whether garlic-induced hemolytic anemia occurs in normal erythrocytes characterized by complete lack of Na-K-ATPase activity with low K and high Na concentrations (LK) dogs are fed large amounts of garlics. We found in this experiment that Erythrocyte count, PCV and Hemoglobin concentration decreased significantly, and GSH and Met-hemoglobin concentrations increased. Consequently we determined that overconsumption of garlic induces hemolytic anemia in LK dogs.

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Effects of carbonized rice hull and wood vinegar on the improvement of cultivation condition and grain quality of rice

  • Cho, Sun-Sik;Heo, Kyu-Hong;Seo, Pil-Dae;Rico, Cyren;Bequillo, Irvin;Kang, Mi-Young;Lee, Sang-Chul
    • Proceedings of the Korean Society of Organic Agriculture Conference
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    • 2009.12a
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    • pp.317-317
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    • 2009
  • The effects of environment-friendly materials carbonized rice hull and wood vinegar on the improvement of rice quality and soil fertility were investigated. Combined application of carbonized rice hull and chemical fertilizer resulted in lower protein in rice, similar amylose content and generally higher palatability values. Combined application of wood vinegar and chemical fertilizer obtained high protein and amylose contents, and palatability values. However, both carbonized rice hull and wood vinegar did not exhibit weed control. In the carbonized rice hull treatments, soil K was high during heading stage while soil pH during harvest stage was low. In the case of wood vinegar treatments, clear distinction between total K and Ca was observed. K was high during tillering stage while Ca was high until harvest stage.

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Quantitative Analysis of Kirenol in Siegesbeckia glabrescens and S. pubescens by HPLC-UV (HPLC-UV에 의한 진득찰과 털진득찰의 Kirenol 정량분석)

  • Nugroho, Agung;Lee, Kyung-Tae;Park, Hee-Juhn
    • Korean Journal of Pharmacognosy
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    • v.43 no.4
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    • pp.286-290
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    • 2012
  • Many diterpenoids from Siegesbeckia species (Compositae) and their anti-inflammatory actions have been examined. In this research, high-performance liquid chromatography-ultraviolet spectrophotometer (HPLC-UV) method was used to compare the quantitative level of kirenol (ent-pimarane-type diterpenoid) in the aerial parts of Korean S. glabrescens and S. pubescens and the Chinese Siegesbeckiae Herba. Fingerprints of the two HPLC chromatograms of Korean S. glabrescens and S. pubescens were similar, but considerably different from Chinese Siegesbeckiae Herba. The content of kirenol in S. pubescens ($16.51{\pm}0.10$ mg/ml dry weight as mean${\pm}$RSD) was higher than S. glabrescens ($13.48{\pm}0.12$ mg/g dry weight). These values were considerably higher than the Chinese Siegesbeckiae Herba ($1.55{\pm}0.74$ mg/g dry weight). Thin layer chromatography (TLC) analysis demonstrated the containing of kirenol in the three plant materials, but the presence of siegeskaurolic acid (entkaurane-type diterpenoid) only in the Chinese Siegesbeckiae Herba.