• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.771-783
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• 1995

A simplified model for the so-called ACRT(accelerated crucible rotation technique) Bridgman crystal growth was considered in order to investigate the principal effects of the periodic variation of angular velocity. Numerical solutions were obtained for Ro=0.5, Ra=4.236*10$_{6}$ and E=2.176*10$^{-3}$ . The effects of spin-up process combined with natural convection was investigated as a preliminary study. The spin-up time scale for the present problem was a little larger than that observed for homogeneous spin-up problems. Numerical results reveal that over a time scale of (H$^{2}$/.nu..omega.$_{f}$)$^{1}$2/ the forced convection due to the formation of Ekman layer predominates. When the state of rigid body rotation is attained, natural convection due to buoyancy emerges as the main driving force and them the steady-state is approached asymptotically. Based on our preliminary results with simple spin-up, several fundamental features associated with variation of rotation speed are successfully identified. When a periodic variation of angular velocity was imposed, the system response was also periodic. Due to effect of mixing, the heat transfer was enlarged. From the analysis of time-averaged Nusselt number along the bottom surface the effect of a periodic variation of angular velocity on the interface location could be indirectly identified.d.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.172.2-172.2
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2015.05a
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• pp.15-16
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• 2015

• Proceedings of the Korean Magnestics Society Conference
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• 2007.12a
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• pp.250-251
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2005.06a
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• pp.58-59
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• 2005

• Proceedings of the Korean Magnestics Society Conference
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• 2011.06a
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• pp.24-24
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• 2011

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.172-177
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• 2000

In this numerical work, three dimensional supersonic laminar flow and heat transfer of a blunt body(sphere-cone) at Mach 5 is simulated. The effects of angle of attack and the spin rate on the now and heat transfer are analysed. To solve the three dimensional compressible Wavier-Stokes equation, a finite volume method with the modified LDFSS scheme is employed for spatial discretization, and a point SGS implicit method is used for time integration. It is found that the heat transfer rate increases at the windward side and decreases at the leeward side with the angle of attack. The heat transfer rate at all surfaces slightly increases with the spin rate.

• World Technopolis Review
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• v.2 no.1
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• pp.21-31
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• 2013

The largest and oldest science and technology park in Korea, Daedeok Innopolis has 29 government research institutes and 5 universities. Every year these research organizations of Daedeok Innopolis are generating more than 7 thousands technology patents and the government tries to commercialize technologies through simple technology licensing to private companies. To facilitate the technology transfer, the new mechanism named research institute spin-offs has been exclusively granted to Daedeok Innopolis in 2006. Since then, the Innopolis Foundation has put lots of effort to activate the mechanism in order to create more commercialization of R&D results from government research institutes (GRIs). This study is undertaken to review the interactive environment of the technology transfer in Daedeok Innopolis and study the unique mechanism which enables Daedeok Innopolis to proceed technology transfer effectively and in particular, looks at the role which can be played by the Innopolis Foundation as a government agent of the policy aimed at facilitating commercialization of using technologies developed by GRIs.

• Journal of Astronomy and Space Sciences
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• v.10 no.1
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• pp.1-16
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• 1993

Three typer of spin-axis attitude determination program for the geosynchronous transfer orbit spacecraft are developed. Deterministic closed-from algorithm, batch least-square algorithm and stabilized Kalman filter algorithm are used for implemetation of three programs. EUROSTAR bus model from British Aerospace is used for attitude sensor modelling. Attitude determinations using three programs are performed for the simulated sensor data according to INMARSAT 2-F1 prelaunch mission analysis.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.6
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• pp.728-732
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• 2014

Macro-model of magnetic tunnel junction (MTJ) for spin transfer torque magnetic random access memory (STT-MRAM) has been developed. The macro-model can describe the dynamic behavior such as the state change of MTJ as a function of the pulse width of driving current and voltage. The statistical behavior has been included in the model to represent the variation of the MTJ characteristic due to process variation. The macro-model has been developed in Verilog-A.