• Title/Summary/Keyword: history of science and technology

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Suggesting Conceptual Framework on the Nature of Technology (NOT) and Investigating College Students' Perceptions Regarding the Nature of Technology(NOT) (기술의 본성(NOT) 개념 틀 제안 및 이공계 대학생들의 기술의 본성(NOT)에 대한 인식 탐구)

  • Baek, Yujin;Lee, Young Hee
    • Journal of Science Education
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    • v.43 no.3
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    • pp.363-381
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    • 2019
  • This study aims to suggest an inclusive conceptual framework for the Nature of Technology (NOT) by examining literature and researches regarding NOT and then to analyze the conceptions of the students in Science and Engineering Department of a college based on the NOT framework. Findings are as follows: First, the conceptual framework of the NOT developed from the study has the five domains of NOT, which are Technology as Artifacts, Technology as Knowledge, Technology as Practice, Technology as History, and Technology as a part of Society. Second, the participants' conceptions of the NOT emphasize on three domains of the Technology as Practice (26.4%), Technology as a part of Society (25.8%), and Technology as Knowledge (24.3%) among the five domains of the NOT. Third, according to the microanalysis of the students' conceptions regarding NOT, students in Science and Engineering Department of a college possess concrete and various views of the NOT even though NOT is abstract and complex ideas. Specifically, they seem to recognize the NOT as a product of process and ability to utilize the technology for convenience of life.

Probabilistic seismic demand of isolated straight concrete girder highway bridges using fragility functions

  • Bayat, Mahmoud;Ahmadi, Hamid Reza;Kia, Mehdi;Cao, Maosen
    • Advances in concrete construction
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    • v.7 no.3
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    • pp.183-189
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    • 2019
  • In this study, it has been tried to prepare an analytical fragility curves for isolated straight continues highway bridges by considering different spectral intensity measures. A three-span concrete isolated bridge has been selected and the seismic performance of the bridge has been improved by Lead Rubber Bearing (LRB). Incremental Dynamic Analysis (IDA) is applied to the bridge in longitudinal direction. A suite of 14 earthquake ground motions from medium to sever motions are scaled and used for nonlinear time history analysis. Fragility function considers the relationship of earthquake intensity measures (IM) and probability of exceeding certain Damage State (DS). A full three dimensional finite element model of the isolated bridge has been developed and analyzed. A wide range of different intensity measures are selected and the optimal intensity measure which has the less dispersion is proposed.

Genetic Homogeneity of the Korean Native Bumble Bee, Bombus ardens (Hymenoptera: Apidae), Detected by Mitochondrial COI Gene Sequences

  • Yoon, Hyung-Joo;Kim, Sam-Eun;Lee, Myeong-Lyeol;Kim, Iksoo;Bae, Jin-Sik;Sohn, Hung-Dae;Jin, Byung-Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.6 no.1
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    • pp.63-68
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    • 2003
  • We investigated the sequence divergence of the geographic samples of the queen bumble bee (Bombus ardens) in Korea. A portion of mitochondrial COI gene sequences (423 bp) was analyzed for 44 individuals collected from seven localities. Sequence analysis resulted in four COI haplotypes with the maximum nucleotide divergence of only 0.5% (two bp). One haplotype (BA1) was dominant in all localities surveyed (86.4%). The finding of low sequence divergence and dominance of one haplotype appear to reflect, although limited, the life history of the B. ardens queens subjected to active dispersal and seasonal fluctuation in queen number.

Polymer meets ceramic: Polymer-driven advancement of ceramic 3D printing technology (고분자와 세라믹의 만남: 고분자를 통한 세라믹 3D 프린팅 기술의 발전)

  • Cha, Chaenyung
    • Ceramist
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    • v.23 no.1
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    • pp.4-15
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    • 2020
  • The recent advances and popularity of 3D printing technology have centered around building polymerbased 'plastic' materials, due to their low cost, simple and efficient processing, and mechanical toughness. For this reason, printable polymers are actively recruited to create 'ceramic resins' that allow more facile fabrication of ceramic materials that are difficult to print directly. Herein, a brief history and the current state of ceramic 3D printing technology aided by polymer is summarized. In addition, a new ceramic 3D printing technology using polymer-derived ceramics (PDC) is also introduced.

Effect of Thermal History on Pitting Corrosion of High Nitrogen and Low Molybdenum Stainless Steels

  • Kim, Kwangsik;Chang, Hyunyoung;Kim, Youngsik
    • Corrosion Science and Technology
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    • v.2 no.2
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    • pp.75-81
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    • 2003
  • Chromium, molybdenum. and nitrogen are very important alloying elements in stainless steels and its effect was approved in pitting resistance equivalent (PRE) equations and many experimental results. However, Cr can improve the corrosion resistance, but facilitate the formation of sigma phase. Also. Mo has the same effect in stainless steels. If Cr and Mo are added at high amount to increase the corrosion resistance of stainless steel, corrosion resistance in annealed alloys can be improved, but in case of welding or aging heat treatment. its resistance will be drastically decreased. In this work, increasing Cr and N contents but decreasing Mo than the commercial alloys made the experimental alloys. Typical alloys are 25Cr-4.5Mo-0.43N alloy, 27Cr-4.7Mo-0.4N alloy, 27Cr-5.3Mo-0.25N alloy, 32Cr-2.6Mo-0.36N alloy. After annealing and aging heat treatment, microstructures, anodic polarization test, and pitting corrosion test were performed. Annealed alloys showed $100^{\circ}C$ of CPT and aged alloys showed the different tendency depending upon Cr and Mo contents(SFI)

The Transition Effect of Korea's Space Development

  • Kim, Jong-bum
    • International Journal of Advanced Culture Technology
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    • v.6 no.2
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    • pp.80-85
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    • 2018
  • In the 1990s, South Korea recently launched Space Development and is pushing for a step toward Space. In the Space Launch Vehicle field, the development of Practical satellite type Launch Vehicle (Korea Space Launch Vehicle II) has progressed to the stage of proprietary development, and in the field of Satellite development, they also have a great deal of competitiveness. This study will be a shortcut to rediscovering our potential and looking for breakthroughs by reviewing and re-examining the effects of past Space development.

The influence of load pulse shape on pressure-impulse diagrams of one-way RC slabs

  • Wang, Wei;Zhang, Duo;Lu, Fangyun
    • Structural Engineering and Mechanics
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    • v.42 no.3
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    • pp.363-381
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    • 2012
  • This study is aimed at providing an efficient analytical model to obtain pressure- impulse diagram of one-way reinforced concrete slabs subjected to different shapes of air blast loading using single degree of freedom method (SDOF). A tri-linear elastic perfectly plastic SDOF model has been used to obtain the pressure-impulse diagram to correlate the blast pressure and the corresponding concrete flexural damage. In order to capture the response history for the slab, a new approximately SDOF method based on the conventional SDOF method is proposed and validated using published test data. The influences of pulse loading shape on the pressure-impulse diagram are studied. Based on the results, a pressure-impulse diagram generation method using SDOF and an analytical equation for the pressure-impulse diagram is proposed to different damage levels and different blast loading shapes.

Development and Situation of Chinese Forest Resources

  • Cheng, Ming;Ahmed, Sheikh Ali;Chun, Su-Kyoung;Kim, Jong-In
    • Journal of the Korea Furniture Society
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    • v.17 no.4
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    • pp.15-26
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    • 2006
  • This article is composed of three parts in this article. The first part reviews, in the general, condition on Chinese forest resource history and analyzes the change in different historical times. The present condition and existing problems are discussed in the second part, where analyzes the existing problems in different distribution areas. In the third part, the solutions are raised to solve the problems mentioned in the second part. Finally the objective and strategy for sustainable development of Chinese forest resources are put forward.

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Entrepreneurial Universities for Science and Technology: Cases of KAIST and POSTECH

  • Park, Mun-su;Jeong, Seung Ouk
    • STI Policy Review
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    • v.5 no.1
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    • pp.131-144
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    • 2014
  • The entrepreneurial university concept is a new challenge and opportunity for science and technology universities in Korea. The traditional university functions of education, research, and community service are still highly relevant, but increasingly so are new types of collaboration for research outcomes and funding resources. Strategic university management is needed to handle socioeconomic contribution, involving the creation and maintenance of proactive relationships with firms, national and regional governments, and other regional entities. The emergence of the entrepreneurial university in Korea is similar to the socioeconomic changes observable in the history of university development in America and in many other developed countries. In this paper, we examine the emerging paradigm of entrepreneurial universities in Korea and discuss the interactions among universities, firms, and government strategy and policy by investigating and comparing two universities, POSTECH and KAIST, in their leadership, adaptation to changes in the environment, business strategies, organization, and cooperative network. We conclude with policy points that emphasize the fact that while entrepreneurial universities are an emerging concept, they can expand innovation and creativity in education and research in Korean universities in the mid-to-long term if university administration, policymakers and public administrators, and regional innovation actors take an interest in the need for a new organization and system where university research can contribute socioeconomically.

The Type Printing of First Ch'ing Dynasty Term (청대 전기의 활자인쇄)

  • Cho Hyung-Jin
    • Journal of the Korean Society for Library and Information Science
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    • v.29
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    • pp.345-382
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    • 1995
  • The type printing of first Ch'ing dynasty term in China is worthy to be studied because the type printing during that period included metal type, wood type, and clay type as well as the development phase was similar to Chosun dynasty culturally and technologically. This paper studied typography during the first Ch'ing dynasty term, including Shunzhi(1662-1722), Yongaheng(1723-1735), Qianlong(1736-1795), Jiaqing(1796­1820) period. The main results of the study is as follows. 1. The main body of type printing was bookstore, lecture-hall, and individual as well as the royal court that is the central government. 2. The content of type edition covers classics, history, philosophy, and literary works. Specifically, even though Wuyingdienjuzhenban series is excluded, the content includs study of the classics, class of the history, class of the philosophy, literature works that include collection works and novel and government official bulletin. 3. The printing technique of bronze type was very popular In Beijing. Jiangsu, and Taiwan. It's scale and production technique was more elaborate than in Ming dynasty. 4. Wood type was very popular in Beijing, Jiangsu, Zhejiang, Anhui, Sichuan, and Fujian. In addition to wood type, chinese ware type was applied to book printing in Shandong. However, most of them were wood type and they were used after Qianlong period. 5. The production technique of type was skilled enough to present the fine view of a style of type. The typesetting technique was improved as much as woodblock printing. With regard to the making technology of Chinese ink, the light and darkness of chinese ink was not even sometimes. But, the technology was improved significantly when comparing with the failure experience of printing that chinese ink was not developed in early type invention. 6. In case that the book was printed in bookstore with the intention of profit and the number of book was large, the proofreading attitude was rough. However, overally, it was made correction carefully applying the various methods of proofreading. 7. The support of government made a great contribution in the area of all printing technology, including production, typesetting, and brushing of type.

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