• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.1
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• pp.8-23
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• 1997

Steady and unsteady numerical simulations are conducted for the comparison with the experiments performed to investigate the ram accelerator flow field by using an expansion tube facility in Stanford University. Wavier-Stokes equations for chemically reacting flows are analyzed by fully implicit and time accurate numerical methods with Jachimowski's detailed chemistry model for hydrogen-air combustion involving 9 species and 19 reaction steps. Although the steady state numerical simulation shows a good agreement with the experimental schlieren and OH PLIF images for the case of $2H_2$＋$O_2$＋$17N_2$ fails in reproducing the combustion region behind the shock intersection point shown in the case of $2H_2$＋$O_2$＋$12N_2$ mixture. Therefore, an unsteady numerical simulation is conducted for this case and the result shows all the detailed flow stabilization process. From the result of unsteady numerical simulation, the experimental result seems to be an instantaneous state during the flow stabilization process. The combustion behind the shock intersection point is the result of a normal detonation formed by the intersection of strong oblique shocks that exist at early stage of the stabilization process. At final stage, the combustion region behind the shock intersection point disappears and the steady state result is retained. The time required for stabilization of the reacting flow in the model ram accelerator is found to be very long in comparison with the experimental test time.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.4
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• pp.27-43
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• 2020

Recently, there has been growing interest in entrepreneurial universities. Accordingly, this study discussed the paradigm shift from traditional university roles to entrepreneurial universities and conducted case analysis of Oxford University, Stanford University and Berlin Institute of Technology from the perspective of ambidextrous strategies of universities. Universities are emphasizing the importance of academic capitalism through market activities as well as the educational and research-oriented role to adapt and survive the rapidly changing uncertain environment. Therefore, many studies related to this have been conducted. This paper discusses the background and necessity of the transformation from traditional universities to entrepreneurial universities, and applies the case of a university that has been successful in transforming into an entrepreneurial universities and creating excellent outcome in terms of ambidextrous strategy. Specifically, this study examined the structural, contextual, and leadership perspectives as a antecedents for ambidextrous strategy. This paper expects not only to introduce cases but also to be used as reference for adapting to future paradigm shifts to entrepreneurial universities and setting the direction of universities.

• Journal of the Korean association of regional geographers
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• v.10 no.2
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• pp.428-446
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• 2004

This paper is to analyze citizens' consciousness on urban changes during the 1900s in the sectors of economy, politics and socio-culture of large cities in Korea, especially comparing them in Seoul, Daejeon, Daegu, and Kywangju. The items of questionnaire are drawn from theories on each sector of new urbanization of large city in Western countries, that is, that of post-Fordism, of urban governance, of post-modernism, and of sustainable city. Some major findings of this questionnaire analysis are as follows. First, on the change of large cities in general, citizens think that the sectors of spatial structure, and of socio-culture of the cities were changed more than those of urban economy and of urban politics. Secondly, in the sector of urban economy, citizens recognize that the obstructing factors of development, that is, the lack of regional capital and the absence of head-quarter of large firms, which seems to be resulted from uneven regional development in the previous periods were much more serious than others, while acknowledging the importance of high-tech industry. Thirdly, in the sector of urban politics, citizens think that the centralized structure of politics and of political parties was still problematic, while acknowledging the importance of entrepreneur mind of urban governor. Finally, in the sector of urban socio-culture, citizens emphasize the development of telecommunication, the popularization of private automobile and the increasing use of credit card, as three major factors which have exercised major impacts on the development of urban socio-culture.

• Knowledge Management Research
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• v.25 no.1
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• pp.21-41
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• 2024

The global Industry has been shaped by start-ups that originated with knowledge-based innovative strategies or technologies in the 21st century. Specifically, laboratory start-ups that rely on research papers or patents for new technology development are recognized for their high survival rate and the creation of employment opportunities. Our study concentrated on 'I-Corps', which also introduced in Korea, standing for innovation corps is a laboratory startup program launched in 2011 by the NSF(National Research Foundation) to commercialize R&D results and foster entrepreneurship as part of the policy to build a start-up system at the national innovation level. In this study, we proposed and empirically tested a research model focusing on teams participating in the I-Corps program to determine how startup team diversity, among the team characteristics of laboratory startups, affected patent performance. As a result of the analysis, among the proposed variables, age diversity, educational background diversity, and value diversity had a significant impact on patent performance. The results of this study are expected to further strengthen the theoretical and practical foundations of researchers or practitioners of the I-Corps program, as well as related areas involving technology & laboratory startups, intellectual property and knowledge management fields in the future.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.38-44
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• 2004

The iron doped colossal magnetoresistance materials with La-Ba-Mn-O perovskites structure have been synthesized by chemical reaction of sol-gel methods. Their crystallographic and magnetic properties have been studied with x-ray diffraction, VSM, RBS, Mossbauer spectroscopy, and magnetoresistance measurements. The crystal structure of the La$\_$0.67/Ba$\_$0.33/Mn$\_$0.99/Fe$\_$0.01/ $O_3$ at room temperature was determined to be orthorhombic of Pnma. The lattice parameters a$\_$0/ and c$\_$0/ increased gradually, but b$\_$0/ deceased with increase of iron substitution. The magnetization and coercivity deceased, also the Curie temperature decreased from 360 K as x increased from 0.00 to 0.05. Magnetoresistence measurements were carried out, and the maximum MR ($\Delta$$\rho$/$\rho$(0)) was observed at 281 K, about 9.5 % in 10 kOe. The temperature of maximum resistance (R$\_$MAX/) decreased with increasing substitution of Fe ions and a semiconductor-metal transition temperature (T$\_$SC-M/) decreased too. This phenomena show that ferromagnetic transition temperature decreased by substituting Fe for Mn ions, it decreases double exchange interaction. This result accords with magnetic structure of neutron diffraction. Mossbauer spectra of La$\_$0.67/Ba$\_$0.33/Mn$\_$0.99/Fe$\_$0.01/ $O_3$were taken at various temperatures ranging from 15 to 350 K. With lowering temperature of the sample, two magnetic phases were increased and finally it showed the two sharp sextets of spectra at 15 K. The isomer shift at all temperature range is about 0.3 mm/s relative to Fe metal, which means that both Fe ions are Fe$\^$3+/ states.Fe$\^$3+/ states.