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Synthesis of spherical SiO2 using scaled-up ultrasonic pyrolysis process (스케일-업 된 초음파 분무 열분해 공정을 이용한 구형 SiO2 분말 합성)

  • Kang, Woo-kyu;Lee, Ji-Hyeon;Kim, Jin-Ho;Hwang, Kwang-Taek;Jang, Gun-Eik
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.1
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    • pp.12-18
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    • 2019
  • The spherical $SiO_2$ powders were synthesized by the scaled-up ultrasonic pyrolysis (USP). The aqueous $SiO_2$ sol, which contained 20~30 nm $SiO_2$ particles, was used as a precursor for the scaled-up USP. The effects of the USP operating conditions and precursor conditions were systematically investigated, including reaction temperature, gas flow rate, and the concentration of $SiO_2$ sol on the morphologies of synthesized $SiO_2$ particles. the synthesized $SiO_2$ particle showed a pseudo-crystal phase, spherical morphology, and a smooth surface. The size of the spherical $SiO_2$ particle decreased as both reaction temperature increased and precursor concentration decreased. In addition, the synthesized $SiO_2$ particle size was increased by increasing the gas flow rate. Lastly, the scaled-up USP was compared with the lab-scale USP based on the same process conditions. Due to a short retention time in the reaction tube during the USP process, the $SiO_2$ particle synthesized via the lab-scale USP showed a larger particle size.

A Research on the Use of Faceted Navigation of KOLIS-NET (KOLIS-NET의 패싯 네비게이션 활용에 관한 연구)

  • Yoon, Cheong-Ok
    • Journal of the Korean Society for Library and Information Science
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    • v.53 no.1
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    • pp.109-132
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    • 2019
  • The purpose of this study is to examine and propose to improve the features of a simple keyword search box and faceted navigations of KOLIS-NET operated by the National Library of Korea. A record group of '2011-2020 (776)' under 'Publication date' facet, out of 3,702 records retrieved from a search of '김훈', were examined. Major findings are as follows: (1) Five facets including 'Format', 'Publication date', 'Subject', 'Language' and 'Country' are used to limit search results only in the first step, and multiple facets cannot be simultaneously used; (2) With 'Publication date' facet formed in the span of ten years, a separate publication year cannot be identified; (3) 'Subject' facet based on KDC limits the results only in broad subject classes without sub-facets; (4) Under 'Format' facet, a special format such as large print texts cannot be identified; (5) Without 'Author' facet, authors cannot be identified; and (6) 'Publication date missing', 'Language missing', and 'Miscellaneous subject' record groups cannot be clicked and displayed, a navigation to-and-fro between a brief list and bibliographic records is not smooth, etc. Therefore an application of multiple facets in all stages of limiting the search result, a construction of sub-facets for 'Publication date' and 'Subject' facets, an accurate description and coding of 'General Material Designation', etc. are suggested to improve KOLIS-NET's faceted navigation.

The Analysis on Technology Acceptance Model for the 3D Printing Industry with the Social Economic Environment Converged Unified Theory Of Acceptance and Use of Technology Model (3D 프린팅 산업에 대한 사회경제환경 융합형 통합기술수용모델을 통한 기업의 3D기술수용의도 분석)

  • Kim, Young-soo;Hong, Ah-reum
    • Journal of Korea Technology Innovation Society
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    • v.22 no.1
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    • pp.119-157
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    • 2019
  • It is important for the people in the 3D printing industry to determine which factors influence the decision-making that determine the adoption of 3D printers and the role of the factors. Through this, we intend to find ways to contribute to the development of 3D printing industry in Korea by increasing utilization of 3D printer used in domestic companies and increasing investment in related industries. 3D printers are making rapid progress according to the development of technology, the public interest, and the activation of investment. Foreign countries have made remarkable progress in equipment, materials, software, and industrial applications, but they are lower than expected in Korea. It is necessary to introduce a smooth 3D printer in order to revitalize the 3D printer industry and enlarge the base, but it is insufficient for actual introduction and field application. The independent variables that represent economic, technological, and environmental characteristics were selected through a literature survey, and a model for accepting integrated technology for convergence of societies in the 3D printing industry was proposed. This study confirms that economic factors such as output unit price, government support, and environmental factors such as 3D contents should be developed organically for the introduction of 3D printing technology and equipment. This require systematic and effective support from the government, and it is necessary to improve the economic support, related laws, and systems that can be directly experienced by the user as a user. As the domestic 3D printing industry develops with economic, technological and time investment, 3D printing industry should be the key engine of the 4th industrial revolution.

Study on Bleaching Effect of Neutralization Agent (Sodium Meta Silicate and Triethylamine) Regarding Its Concentration - Focused on 10% Urea Hydrogen Peroxide Bleaching Gel - (도자기 표면 변색에 대한 중화제(Sodium Meta Silicate 및 Triethylamine)의 농도별 표백 효과 - 10% 과산화요소 표백겔을 중심으로 -)

  • Ham, Chul Hee
    • Korean Journal of Heritage: History & Science
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    • v.44 no.4
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    • pp.130-141
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    • 2011
  • This paper examined the bleaching effect of the two types of gel made with neutralizing agent such as sodium meta silicate gel & triethylamine gel mixed with carbopol resin 940 & 934 which has thickness effect in broad pH region and mixed with 10% hydrogen peroxide. Sodium meta silicate gel(1.6g included) provided pH 10, the most suitable environment for bleaching. The result of comparison of the baseline colour changes(${\Delta}E*ab$) and colour changes according to time(${\Delta}E*ab$) is as following. Group1(carbopol 940, sodium meta silicate, Urea Hydrogen Peroxide) showed 112% efficiency at CS-2; 63.3% at CS-4; 87.4% at CS-6. Group2(carbopol 934, sodium meta silicate, Urea Hydrogen Peroxide) showed 77.3%, 67.3%, 109.6% at CS-8, CS-10, CS-12 respectively; CT-1, CT-3, CT-5 of Group3(carbopol 940, triethylamine, Urea Hydrogen Peroxide) showed 36.8%, 73.2%, 74%; In Group4(carbopol 934, triethylamine, Urea Hydrogen Peroxide), efficiency of CT-6, CT-8, and CT-10 was 81.7%, 95.4%, and 95.7%. The paper showed that various concentration of neutralizing agent such as sodium meta silicate and triethylamine have bleaching effect. Viscosity of the gel including sodium meta silicate was higher than the gel including triethylamine. High viscosity helps the bleaching gel sit on the smooth slope of the ceramics. As a result, sodium meta silicate is considered to provide thickening and bleaching effect required in producing 10% hydrogen peroxide gel.

A Study on the the Follow-up Analysis and the Characteristics of Exhaust Gas by Standard Mode of Chassis Dynamometer of Gasoline (가솔린 차량의 차대동력계 표준모드 별 추종성 분석 및 배출가스 특성에 관한 연구)

  • Seo, Dong Choon;Park, Sung-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.9
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    • pp.29-34
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    • 2019
  • In this study, a gasoline test vehicle was evaluated for drive quality in emissions and fuel economy tests. The measurement results were compared with the manufacturer's suggested values to evaluate whether the tolerance ranges (fuel efficiency -5%, greenhouse gas +5%) were exceeded. We carried out tests with test subjects based on the SAE J2951 evaluation method. The test vehicle was a 2L gasoline vehicle. The drive following performance was found to increase under deliberate driving conditions and decreased in smooth driving conditions. As a result of the analysis of the drive following performance, the closer the value is to 1, the more accurate the driving is. (-) indicates harsh conditions, and (+) indicates gentle conditions. The basic data on the driver following between testers was obtained by analysis of the tests. The fuel efficiency correlation with the drive following performance within the target speed range of the fuel consumption mode. In the future, these measurement results can serve as key data for securing an exhaust gas database and fuel efficiency system for each measurement mode.

Activation of Korean Ship Finance through Study on Chinese Ship Finance Market (중국 선박금융 시장 연구를 통한 국내 선박금융 활성화)

  • Kim, Dae-Jin;Kim, Ju-Hyeoun
    • Journal of Korea Port Economic Association
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    • v.35 no.2
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    • pp.1-20
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    • 2019
  • This study aims to establish a method for activating Korean ship finance through an analysis on the development of Chinese ship finance market, which has grown rapidly in recent years. It focuses on its main institutions, laws and policies, strengths and weaknesses, market share, and development status. Because 80.7% of South Korea's economy depends upon foreign trade and 99.7% of the South Korea's traded volume is transported by ships, shipping has assumed an important role in Korean economy. However, since the global financial crisis, Korean shipping and shipbuilding industry has been facing difficulties and Hanjin, the biggest Korean shipping company, went bankrupt in 2017. One of the key aspects of the competitiveness of the shipping and shipbuilding industry is acquiring competitive shipping assets; therefore, stable and smooth supply of ship finance is crucial for the development of the shipping and shipbuilding industry. Given this background, the study analyzed how the Chinese ship finance market has grown rapidly in the past 30 years and identified the problems, strengths, and weaknesses of the Chinese ship finance. The analysis on the status of the Chinese ship finance market is expected to suggest a direction for establishing methods for activating the Korean ship finance market, which is facing scarcity of finance, even as the global ship finance market has remained depressed since the global financial crisis. Although this study focused exclusively on the Chinese market, future research can draw conclusions from a comparative analysis that includes the Japanese ship finance market; the conclusions obtained would contribute to the establishment of long-term policies and plans for Korean ship finance.

Carpinus turczaninowii extract modulates arterial inflammatory response: a potential therapeutic use for atherosclerosis

  • Son, Youn Kyoung;Yoon, So Ra;Bang, Woo Young;Bae, Chang-Hwan;Yeo, Joo-Hong;Yeo, Rimkyo;An, Juhyun;Song, Juhyun;Kim, Oh Yoen
    • Nutrition Research and Practice
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    • v.13 no.4
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    • pp.302-309
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    • 2019
  • BACKGOURND/OBJECTIVES: Vascular inflammation is an important feature in the atherosclerotic process. Recent studies report that leaves and branches of Carpinus turczaninowii (C. turczaninowii) have antioxidant capacity and exert anti-inflammatory effects. However, no study has reported the regulatory effect of C. turczaninowii extract on the arterial inflammatory response. This study therefore investigated modulation of the arterial inflammatory response after exposure to C. turczaninowii extract, using human aortic vascular smooth muscle cells (HAoSMCs). MATERIALS/METHODS: Scavenging activity of free radicals, total phenolic content (TPC), cell viability, mRNA expressions, and secreted levels of cytokines were measured in LPS-stimulated (10 ng/mL) HAoSMCs treated with the C. turczaninowii extract. RESULTS: C. turczaninowii extract contains high amounts of TPC ($225.6{\pm}21.0mg$ of gallic acid equivalents/g of the extract), as well as exerts time-and dose-dependent increases in strongly scavenged free radicals (average $14.8{\pm}1.97{\mu}g/mL$ $IC_{50}$ at 40 min). Cell viabilities after exposure to the extracts (1 and $10{\mu}g/mL$) were similar to the viability of non-treated cells. Cytokine mRNA expressions were significantly suppressed by the extracts (1 and $10{\mu}g/mL$) at 6 hours (h) after exposure. Interleukin-6 secretion was dose-dependently suppressed 2 h after incubation with the extract, at $1-10{\mu}g/mL$ in non-stimulated cells, and at 5 and $10{\mu}g/mL$ in LPS-stimulated cells. Similar patterns were also observed at 24 h after incubation with the extract (at $1-10{\mu}g/mL$ in non-stimulated cells, and at $10{\mu}g/mL$ in the LPS-stimulated cells). Soluble intracellular vascular adhesion molecules (sICAM-1) secreted from non-stimulated cells and LPS-stimulated cells were similarly suppressed in a dose-dependent manner after 24 h exposure to the extracts, but not after 2 h. In addition, sICAM-1 concentration after 24 h treatment was positively related to IL-6 levels after 2 h and 24 h exposure (r = 0.418, P = 0.003, and r = 0.524, P < 0.001, respectively). CONCLUSIONS: This study demonstrates that C. turczaninowii modulates the arterial inflammatory response, and indicates the potential to be applied as a therapeutic use for atherosclerosis.

A Qualitative Study on the Procedures and Characteristics of reading service Provision at Center of Archival Information of National Archives of Korea (국가기록원 기록정보센터의 열람서비스 제공 절차 및 특징에 관한 질적 연구)

  • Nam, Yeun-Ah;Yim, Jin Hee
    • The Korean Journal of Archival Studies
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    • no.50
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    • pp.177-229
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    • 2016
  • Archival reference service is the ultimate goal and outcome of records management. It encompasses a whole range of activities to connect records with the demands for them. Intellectual needs for records are met by the procedure of information disclosure to guarantee the people's right to know and to provide active responses to archival information needs. Thus, it is required to establish an efficient search system by unifying search tools for archives used in information disclosure and sorting out the classification systems and description items according to the archive types. The qualitative enhancement of information disclosure can be expected when there is a harmonious circulation of attributes-such as applicants, records, search tools, and information providers-for the smooth implementation of reading processes in the context of archival reference service. Therefore, the present study holds its significance in the following aspects. First, it presented a picture of pending issues and the reality of reading service processes from an internal perspective by examining the factors and characteristics that influence "reading service."Second, it demonstrated the phenomenon of close interactions among information providers, applicant, search tools, and records in the process of requesting, searching, and providing records. Third, it proposed the need for a total integrated search tool around the pending issues of reading processes at the National Archives of Korea. Fourth, it promoted an understanding of archival information utilization at the working level among information providers. Finally, it showed major differences in the quality of information provision of "reading service" according to the "perceptions" and "attitudes" of information providers.

Comparative Study on the Perception of Specializing Libraries of Non-Specialized Library Librarians and Users (도서관 특화에 대한 비특화도서관 사서와 이용자의 인식비교 연구)

  • Noh, Younghee;Shin, Youngji;Kwak, Woojung
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.30 no.1
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    • pp.77-99
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    • 2019
  • In this study, development directions for smooth introduction of transferring non-specialized libraries to specialized libraries are suggested based on the analysis conducted on non-specialized library librarians and users to investigate and analyze the comparative requirements for specializing libraries, specialization topics, demand for spaces and programs for specialization and view of important factors of each area when operating specialized libraries in future. As a result, first, when introducing a specialized library, it is necessary to derive a specialized topic that can identify and provide the characteristics of the region and the status of existing library. And a demand analysis. Based on this, the subject should be selected through the demand survey of the local residents. Second, from the stand point of targeted subjects of specialized service, it is necessary to provide tailored services by understanding the service range for each age group based on local population distribution and library user analysis. Third, experience-type, lecture-type and view-type can be suggested for specialized programs, considering the characteristics of the specialized subject field. It is ideal to operate combination of the three based on the subject filed details. Also, the characteristics of the subject and the types of program should be considered for specialized spaces. Finally, in order to systematically operate and promote specialized libraries, allocating dedicated personnel, linking with other institutions and strategies of promotion and marketing should be considered.

A Study on the Archiving of a Social Phenomenon through Neologism (신조어를 활용한 사회적 현상 아카이빙 방안 연구)

  • Kim, Hwan;Yim, Jin Hee
    • The Korean Journal of Archival Studies
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    • no.52
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    • pp.315-342
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    • 2017
  • Language is an important medium for communication among the members of society and a mirror that reflects society as a whole. As society and culture change and develop over centuries, language follows suit. To keep up with the changes in the new era and express new concepts, countless new neologisms continue to appear. Recently, the use of neologisms is getting increasingly focused on social networking service and other Internet communication sites, which then spread rapidly through various media. If you look at the popular neologisms on the Internet, it implicitly reflects conflicts between the eras and the generations, people's psychology and ideology, and social phenomena such as culture. The function of neologisms is not solely for the entertainment element of communication but also for criticizing social problems and their vital use as a search keyword. This study focuses on the meaning and importance of gathering information and analyzing records about neologisms that reflect the social phenomenon in a certain period, and this will be labeled as "neologism archiving." This study proposes a direction for the construction of a neologism archive by comparing the currently existing neologism archiving system with the existing dictionary concept. In addition, this study serves as a reminder of the convenience and the contemporary social phenomena, such as smooth communication between generations, and the dissemination of inequality of information sharing. Lastly, this study aims to support experts with their research on neologisms for the social phenomenon.