• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.3
• /
• pp.404-408
• /
• 2014

In this research we evaluate the excitation homogeneity and SAR of three different Tx arrays after B1+ Shimming in the human body at 3T. Through the simulations, we compared the field properties that are standard deviation and mean value of transverse magnetization for 1) strip line TEM array, 2) rectangular loop array, 3) combined array of strip line element and rectangular loop and shown the utilities of B1+ shimming in human body model. After B1+ shimming, it is evaluated four different types of SAR for body mesh through whole body simulation; those are average, maximum 1-cell, maximum 1-gram, and maximum 10-gram SAR. It appears that in this particular comparison an array based on strip line elements can produce better homogeneity and lower SAR than an array of rectangular loops or an array of combined elements (strip line and loop). While many factors are considered in designing coils for production, it is hoped that methods and results like these will be used in the future to guide decisions and maximize benefit.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.08a
• /
• pp.336-345
• /
• 2004

Investigated via a series of finite-element(FE) process simulation is the effect of diverse process variables on some selected non-dimensional parameters characterizing the thermo-mechanical behavior of the roll and strip in hot strip rolling. Then, on the basis of these parameters, on-line models are derived for the precise prediction of the temperature changes occurring in the bite zones as well as in the inter-stand zones in a finishing mill. The prediction accuracy of the proposed models is examined through comparison with predictions from a FE process model.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.395-398
• /
• 1998

In this paper, the design, fabrication, and experiments of linearly tapered slot antenna(LTSA) with uniplanar microstrip-to-coplanar strip(CPS) line transitions are presented. The effect of reducing and increasing with taper width G teper longth 1, and opening angle are also mesured at 10 GHz.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2000.04a
• /
• pp.52-55
• /
• 2000

Investigated via a series of finite element process simulation is the effect of diverse process variables on some selected non-dimensional parameters characterizing the strip in hot strip rolling. Then on the basis of these parameters an on-line model is derived for the precise prediction of roll and roll power. The prediction accuracy of the proposed model is examined through comparison with predictions from a finite element process model.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.170-170
• /
• 2000

This paper deals with on-Line detection of strip movement and real time positioning of brackets of EMD connected with it. Strip movement is detected by 4 line CCD camera and measured position correction value is inputted to motor position controller to control position of brackets.

• International Journal of Control, Automation, and Systems
• /
• v.2 no.1
• /
• pp.55-67
• /
• 2004

In this paper, an active vibration control of a translating steel strip in a zinc galvanizing line is investigated. The control objectives in the galvanizing line are to improve the uniformity of the zinc deposit on the strip surfaces and to reduce the zinc consumption. The translating steel strip is modeled as a moving belt equation by using Hamilton’s principle for systems with moving mass. The total mechanical energy of the strip is considered to be a Lyapunov function candidate. A nonlinear boundary control law that assures the exponential stability of the closed loop system is derived. The existence of a closed-loop solution is shown by proving that the closed-loop dynamics is dissipative. Simulation results are provided.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.838-840
• /
• 1998

$BiNbO_4$ ceramics with 0.06wt% CuO, 0.1wt% $V_{2}O_{5}$ sintered at $900^{\circ}C$. The strip line chip filter has been design and fabricated by screen printing with silver electrode after tape casting. The characteristics of the fabricated filters were compared with the simulated results. In the strip line chip filter, insertion loss value of band pass width was 3.65[dB] and return loss was 8.9[dB] and center frequency was similar that simulation results.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.1096-1098
• /
• 2000

This paper proposes a tension control to compensate friction loss using on-line friction torque observer for a continuous strip processing line. Friction loss of roller results in significant deviation of strip tension. accordingly it has an influence on the operation of other adjacent rolls. To avoid tension variation of the strip, a friction torque observer is designed in adjacent roll, which operates in speed control mode. The experimental results show improvement of tension control performance by the proposed friction compensation method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.08a
• /
• pp.175-183
• /
• 2004

In hot strip rolling, a capability for precisely predicting roll force is crucial for sound process control. In the past, on-line prediction models have been developed mostly on the basis of Orowan's theory and its variation. However, the range of process conditions in which desired prediction accuracy could be achieved was rather limited, mainly due to many simplifying assumptions inherent to Orowan's theory. As far as the prediction accuracy is concerned, a rigorously formulated finite element(FE) process model is perhaps the best choice. However, a FE process model in general requires a large CPU time, rendering itself inadequate for on-line purpose. In this report, we present a FE-based on-line prediction model applicable to precision process control in a finishing mill(FM). Described was an integrated FE process model capable of revealing the detailed aspects of the thermo-mechanical behavior of the roll-strip system. Using the FE process model, a series of process simulation was conducted to investigate the effect of diverse process variables on some selected non-dimensional parameters characterizing the thermo-mechanical behavior of the strip. Then, it was shown that an on-line model for the prediction of roll force could be derived on the basis of these parameters. The prediction accuracy of the proposed model was examined through comparison with measurements from the hot strip mill.

• Transactions of Materials Processing
• /
• v.11 no.1
• /
• pp.24-35
• /
• 2002

Recent trend and future prospect of flat rolling of steel has been summarized based on the earlier reports. Key technology in the plate rolling is to have ultra fine microstructure having high resistance against crack propagation during application. Heavy accelerated cooling facility and high power rolling mill will be helpful to develope the high toughness steel. Precise modeling of properly prediction based on deformation and transformation imposed on microstructure of steel during processing is highly anticipated. For the hot strip rolling process, new trend is lies on the production of ultra-thin gauged hot strip to substitute cold rolled strip. For the substitution of cold rolled strip into hot rolled strip widely, high formable property of hot strip is highly required. For the formabilit, the ferritic rolling of extra low carbon steel under high lubricated condition is essential. Recently introduced semi-continuous thin slab and rolling mill line is very plausible to develope those kinds of products easily In the view groin facility combination. New idea to modify the existing continuous hot strip mill line to produce the ultra thin-gauged hot strip in an economic way is suggested in this report.