• Structural Engineering and Mechanics
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• v.27 no.6
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• pp.683-696
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• 2007

This article is concerned with the presentation of a time-domain BEM approach applied to the solution of the scalar wave equation for 2D problems. The basic idea is quite simple: the basic variables of the problem at time $t_n$ (potential and flux) are computed with the results related to the potential and to its time derivative at time $t_{n-1}$ playing the role of "initial conditions". This time-marching scheme needs the computation of the potential and its time derivative at all boundary nodes and internal points, as well as the entire discretization of the domain. The convolution integrals of the standard time-domain BEM formulation, however, are not computed; the matrices assembled, only at the initial time interval, are those related to the potential, flux and to the potential time derivative. Two examples are presented and discussed at the end of the article, in order to verify the accuracy and potentialities of the proposed formulation.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.432-441
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• 1998

The electrocardiogram (ECG) and electrolytes were measured to obtain diagnostic data after experimental obstruction of duodenum in 8 dogs. Clinical signs of these appeared lower heart rate, temperatures respiration and blood pressure than signs of preoperation. In changes of electrolytes and acid-base balances, all dogs appeared hyponatremiai hypochloremia, metabolic alkalosis, and increased pHi HCO3, scot in blood, but potassium values appeared to increase in 3 cases fl-inc.) and to decrease in 5 cases (K- dec.) Two of three in K-inc. and three of five in K-dec. died at 60 hrs and 72 hrs after obstruction respectly. In changes of ECGI amplitudes of the K-inc cases appeared high in T wave and low in R wave, but amplitudes of the K-dec cases appeared low T waver 57 segment and high in R wave. Conduction times of the K-inc appeared the shorted PR intervals but the K-dec appeared the prolonged PR interval. The changes of these appeared apparently in lead II.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.21-27
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• 2001

This paper describes numerical analysis of the impulse turbine with fixed guide vanes, a high performance bi-directional air turbine having simple structure for wave energy conversion. The numerical analysis of the 2-dimensional incompressible viscous flow based on the full Reynold-averaged Navier-Stokes equations which was made to investigate the internal flow behavior. Numerical results are compared with experimental data obtained by T.Setoguchi laboratory. As a result, as suitable choice of design factor has been clarified with the understanding of the internal flow from the numerical analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2006.08a
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• pp.60-60
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• 2006

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.18-24
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• 2002

n this paper, we have fabricated pseudomorphic high electron mobility transistors (PHEMT) with a 0.2 ${\mu}{\textrm}{m}$ wide-head T-shaped gate using electron beam lithography by a dose split method. To make the T-shape gate with gate length of 0.2 ${\mu}{\textrm}{m}$ and gate head size of 1.3 ${\mu}{\textrm}{m}$ we have used triple layer resist structure of PMMA/P(MMA-MAA)/PMMA. The DC characteristics of PHEMT, which has 0.2 ${\mu}{\textrm}{m}$ of gate length, 80 ${\mu}{\textrm}{m}$ of unit gate width and 4 gate fingers, are drain current density of 323 ㎃/mm and maximum transconductance 232 mS/mm at $V_{gs}$ = -1.2V and $V_{ds}$ = 3V. The RF characteristics of the same device are 2.91㏈ of S21 gain and 11.42㏈ of MAG at 40GHz. The current gain cut-off frequency is 63GHz and maximum oscillation frequency is 150GHz, respectively.ively.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.3
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• pp.9-16
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• 2008

We centrally study effect of very high voltage 345kV T/L which is set up at residential area (Yangyang~Donghae in Gangwon-do) to broadcasting radio wave and human body. First, to compare predicted result of radio wave disturbance, we set 7 area 13 point and divide broadcasting quality, electric and magnetic fields in T/L process. Result of estimation, we confirm that when receiving broadcasting radio wave, broadcasting quality's difference is generated by topographic property of near receiving point. also through result of electric fields and broadcasting quality and their comparison, we judge that high voltage T/L is barely affect receive of broadcasting radio wave. To judge effect of magnetic fields to human body, we analyze magnetic fields in variable area and condition. as a result, magnetic fields of every area has 1.8mG(WHO international standard amount is 833mG). So It is proved that magnetic fields of 345kV Yangyang~Donghae area has slight, tiny effect to human body.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1471-1478
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• 2011

A typical standard of vehicular ad hoc networks, WAVE which consists of IEEE 1609.x Family standards and IEEE 802.11p standard, includes the multi-channel coordination and channel synchronization function to provide safety services or public services during a car is driven. Generally, the performance of data communication and networking technologies is evaluated by using simulation tools, such as ns-2, OPNET, OPNET++, etc. However, these tools doesn't provide the operations of WAVE protocol. Therefore, in this paper, we implement and verify WAVE simulation program based on ns-2.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.17-18
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.437-438
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• 2009

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.45-45
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• 2001