• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.511-517
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• 2001

We evaluated the electrical properties of 37 multifilamentary jointed tapes processed by superconducting joint. In the superconducting joining method, a lap-joint was used. Tapes were selectively etched, and exposed superconducting cores of the two tapes were brought into contact with each other and then only the joined region was uniaxially pressed in the range of 1,000 to 2,50 MPa. The critical current ratio(CCR) and n-value of the jointed tape were evaluated as a function of uniaxial pressure and number of step in the contacting region. It was observed that the CCR was dependent on the number of step, but almost independent of uniaxial pressure. The highest critical current ratio and n-value were obtained to be 58% and 26%, respectively, for the jointed tape to the tape itself.

• Journal of architectural history
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• v.6 no.1 s.11
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• pp.67-79
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• 1997

Architecture is a shelter for society whose social pattern requires a specific form to accord with its material and spiritual needs. Providing a truly acceptable architecture requires our deeper understanding of cultural tradition - mythic values - not only because myth is an interpreted and configured form of 'thing' through man's second nature, such as his subjective and objective consciousness -'self-revelation of the absolute'- but also because, in the world of mythical imagination, a fragment of substantial reality -'thing'- becomes an equivalent mode to the signification, and emerges as 'its independent spiritual form' and 'the characteristic force of the logos.' In this sense, myth of place and myth behind tectonic form are the most essential sources for comprehending people's relationship to the world of inner and conscious experience. The recent efforts of modern architects to achieve cultural continuity should begin with re-interpretation and configulation of the myths behind describable material culture, especially artistic imagination inspired by deeper understanding of the myth of place. Myth provide artists with a creative inspiration, as they did in the past.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.37-38
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• 2008

In this paper, we have developed Organic light-emitting devices(OLEDs) using various thicknesses of new electron transport layer. The device structure of ITO/ 2-TNATA(15nm)/ DPVBi(40nm)/ New ETL(20nm,60nm,100nm)/ LiF(0.5nm)/Al(100nm) has been used. The operating voltage of the device was almost independent of the new ETL thickness, due to its high electron conducting property. For example, the operating voltages of the devices with 20nm and 60nm layers are almost 5V at a current density $200mA/cm^2$. The device with the new ETL shows the low turn-on of 2.5V.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.3
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• pp.559-580
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• 1997

It is essential to construct on efficient material flow system for the successful introduction of automated manufacturing systems. Automated Guided Vehicle System(AGVS) ploys a significant role more and more in modern manufacturing environments, because of the flexibility and the precision they offer. However, as the size and the complexity of systems increase, the problems of dispatching, routing and scheduling of AGVs became complicated due to their independent and asynchronous demands. In this paper, we review relevant papers, and provide a new and more efficient method for partitioning the AGV system by introducing the concept of Central Path. This method named Central Path design has advantages, since each partitioned workstation group is served by one AGV and the material handling between groups is performed by special AGV that is used for the Central Path. Therefore the congestion problems never occur. Furthermore Central Path Design has a high flexibility for alteration and extension of system. Finally, we demonstrate its efficiency using simulation.

• Journal of Institute of Convergence Technology
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• v.6 no.2
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• pp.1-7
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• 2016

The rotating electrodynamic wheels can produce three-axial forces on the conductive target. The forces are linked strongly each other, and their magnitudes depend on the rotating speed of the wheel. However, the wheels can be used effectively as an actuating principle for transfer system of conductive material. The conductive material is a pipe with a constant cross-section or a conductive plate. In this paper, a few applications using the electrodynamic wheels as transferring means are introduced including the full description of the real hardware implementation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.13-16
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• 1998

An anomalous current characteristics which show the superposition of a low current level and high current level at the subthreshold region when SONOSFETs are in memory states were investigated. We have assumed this phenomena were resulted from the effect of parasitic transistors by LOCOS isolation and were modeled to a parallel equivalent circuit of one memory transistor and two parasitic transistors. Theoretical curves are well fitted in measured log I$_{D}$-V$_{G}$ curves independent of channel width of memory devices. The difference between low current level and high current level is apparently decreased with decrease of channel width of devices because parasitic devices dominantly contribute to the current conduction with decrease of channel width of memory devices. As a result, we concluded that the LOCOS isolation has to selectively adopt in the design of process for charge-trap type NVSM.VSM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.63-67
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• 2008

The charged particle type display is a kind of electronic paper showing information images using positive and negative charged particles ($<10{\mu}m$). In this work we used yellow(-) and black(+) particles which are respectively addressed to the cells of a upper and a rear substrate by using electric field. Our independent addressing method has strong points compared to the mixed particle putting method. The packaging with two orthogonal substrates and the aging process is followed by addressing process. The panel is sequentially driven by matrix method for each 4-unit cells. Layers of particles are controlled by barrier ribs and must be addressed to minimum 2 layers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.210-213
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• 2004

Based on plastic instability, analytical prediction of bursting failure on tube hydroforming processes under combined internal pressure and independent axial feeding is carried out. Bursting is irrecoverable phenomenon due to local instability under excessive tensile stresses. In order to predict the bursting failure, three different classical necking criteria such as diffuse necking criterion for sheet and tube, local necking criterion for sheet are introduced. The incremental theory of plasticity fur anisotropic material is adopted and then the hydroforming limit and bursting failure diagram with respect to axial feeding and hydraulic pressure are presented. In addition, the influences of the material properties such as anisotropy parameter, strain hardening exponent on bursting pressure are investigated. As results of the above approach, the hydroforming limit in view of bursting failure is verified with experimental results.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.474-477
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• 2006

To predict thermal stress independent of uncertain material properties of early age concrete, such as elastic modulus and creep, thermal stress device is used. In order to verify the application of various degree of constraint in the thermal stress device, a series of experiments were performed on mass concrete followed by numerical simulation. The application of various degrees of constraint can be achieved by using constraint frame material with different thermal expansion coefficient, length, and cross sectional area. Temperature development in the real structure has been simulated using temperature and humidity control chamber. The results from experiments and numerical analysis show that the thermal stresses estimated from simulation agree well with the general stress variations in the real structure even though the properties of concrete are uncertain.

• Structural Engineering and Mechanics
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• v.5 no.3
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• pp.221-237
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• 1997

This paper presents a new uniaxial material model for rate-sensitive analysis addressing both the transient and steady-state responses. The new model adopts visco-plastic theory for the rate-sensitive response, and employs a three-parameter representation of the overstress as a function of the strain-rate. The third parameter is introduced in the new model to control its transient response characteristics, and to provide flexibility in fitting test data on the variation of overstress with strain-rate. Since the governing visco-plastic differential equation cannot be integrated analytically due to its inherent nonlinearity, a new single-step numerical integration procedure is proposed, which leads to high levels of accuracy almost independent of the size of the integration time-step. The new model is implemented within the nonlinear analysis program ADAPTIC, which is used to provide several verification examples and comparison with other experimental and numerical results. The companion paper extends the three-parameter model to trilinear static stress-strain relationships for steel and concrete, and presents application examples of the proposed models.