• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1881-1883
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• 2001

We manufactured a micro CPL by LlGA process, a new conceptual ultra-fine and precise forming method, using X-ray lithography process. We fabricated a BN X-ray mask having properties of good X-ray transmittance and large mechanical strength. Micro CPL was manufactured by dividing into an upper plate and a low plate. Each of plates was bonded by Ag paste screen printing. The upper plate was fabricated on glass wafer to observe flow and phase transformation of cooling solution. The lower plate was manufactured by Cu electroplating for good heat transmission. Precision of inner Parts, micro pin and micro channel, of manufactured micro CPL is under ${\pm}2{\mu}m$.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.103.1-103.1
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• 2011

Recent observations by Hinode show weakly-attenuated coronal loop oscillations in the presence of background flow (Ofman & Wang 2008, A&A, 482, L9). We study the vertical kink oscillations in solar coronal loops, considering field aligned flows inside the loops as well as surrounding the loops environment. The two dimensional numerical model of straight slab is used to explore the excitation and attenuation of the impulsively triggered fast magnetosonic standing kink waves. A full set of time dependent ideal magnetohydrodynamics equations is solved numerically taking into account the value of flow of the order of observed flows detected by SOT/Hinode. We find that relaxing the assumption of the limited flows within the loops enhances the damping rate of the fundamental mode of the standing kink waves by 2 - 3 % as compared to flow pattern which is basically localized within the loops. We further notice that extending the flow pattern beyond the loop thickness also enhances the strength of the shock associated with slow magnetoacoustic waves, recognized as an addition feature detected in the numerical simulation. The wider out-flow pattern destroys the oscillation patterns early as compared to narrower flow pattern, in other words we can say that it affects the durability of the oscillation. However, for the typical coronal loops parameters we find that the observed durability periods of the SOT/Hinode observation can be achieved with an out-flow Gaussian patterns for which half-width is not greater than factor 2.0 of the loop-half-width. explain a possible relation between electric current structure and sigmoid observed in a preflare phase.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.267-272
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• 2007

In the construction industry government is not only an owner but also a consumer. Accordingly it should develop the construction industry and this role is important. Among them, the law of the ordering method is standards of selecting a successful bidder and have powerful influence over the construction industry and owners. Therefore this study said how the lowest bid method, which has taken effect still more, has influence on the construction industry and the public sector with the Causal Loop Diagram. According to analyzing this construction law, we can grasp the point of the strength and weakness of this law also examine a trend of how the present law is changed. While we studied, we tried to adhere to neutrality and form a new opinion about it because the previous studies were opposed to each other. As a result, to improve the relation between the government and private company, which were opposed to each other about arguments for and against the lowest bid method, this study suggest the method of making better the relation. The final goal of it is researching the inefficient factors and improving the weakness of this law.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.150-153
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• 1994

Magnetic field annealing method has been used to obtain proper hysteresis loop shapes which are useful to a device using amorphous ribbon. In this study, two pairs of Helmhotz coils were used to apply longitudinal and transverse magnetic field during annealing. For the measurement of coercive field strength noise which depends on magnetic field annealing, Co-based amorphous alloy ribbon $VITROVAC^{\circledR}$ 6030 was used. For the sample which was annealed under dc transverse and dc longitudinal magnetic field, coercive field strength noise was nearly independent of magnetizing frequency ranging from 1 to 100 kHz, but dc transverse and ac longitudinal magnetic fields annealed samples show that the coercive field strength noise decreased in power of magnetizing frequency. When magnetic domain nucleation occurred, the coercive field strength noise increased remarkably and decreased in power of magnetizing frequency.

• Earthquakes and Structures
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• v.17 no.1
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• pp.49-61
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• 2019

A novel asymmetrical resistance friction damper (ARFD) was proposed in this study to be applied on a rocking column base. The damper comprises multiple steel plates and was fastened using high-strength bolts. The sliding surfaces can be switched into one another and can cause strength to be higher in the loading direction than in the unloading direction. By combining the asymmetrical resistance with the restoring resistance that is generated due to an axial load on the column, the rocking column base can develop a self-centering behavior and achieve high connection strength. Cyclic tests on the ARFD proved that the damper performs a stable asymmetrical hysteretic loop. The desired hysteretic behavior was achieved by tuning the bolt pretension force and the diameter of the round bolt hole. In this study, full-scale, flexural tests were conducted to evaluate the performance of the column base and to verify the analytical model. The results indicated that the column base exhibits a stable self-centering behavior up to a drift angle of 4%. The decompression moment and maximum strength reached 42% and 88% of the full plastic moment of the section, respectively, under a column axial force ratio of approximately 0.2. The strengths and self-centering capacity can be obtained by determining the bolt pretension force. The analytical model results revealed good agreement with the experimental results.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.61-64
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• 2000

In this paper, we design up-down converter for asynchronous IMT-2000 base station using W-CDMA(Wideband Code Division Multiple Access) technology. This up-down converter(UDC) has AGC (Automatic Gain Control), TPTL(Transmitting Power Tracing Loop), RSSI(Received Signal Strength Indicator) function. And for the cell control of BS(Base Station), breathing, blossoming, wilting function also available. This UDC has diversity structure for better performance.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.554-559
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• 1986

This paper considers the problem of stabilizing a composite system formed by interconnecting a number of single-input single-output linear continuous systems. The problem is general in the sense that in addition to the standard assumption about the uncertainty of the subsystems, the strength of interconnections is assumed unknown. A method to design a local adaptive feedback control is first presented, and then the resultant closed-loop system is assured to be globally stable. Also, a numerical example is illustrated via computer simulation.

• Composites Research
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• v.15 no.1
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• pp.61-69
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• 2002

This paper review research activities of some mechanical test methods thor advanced composites which have been conducted in Fukuda laboratory. Tokyo University of Science. The subjects are (1) innovation and development of compression bending test. (2) mechanical-property evaluation of soft-core sandwich beam, and (3) loop test to measure the strength of monofilaments.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.897-902
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• 2000

In most of large panel pre-cast concrete system, the narrow joints have inefficiency to assemble several panels and structural problems due to their complicated process after construction. To improve, practically, structural performance and inefficiency to assemble, the behavior and strength of new wide joints method should be investigated experimentally. The result is that the shear force of wide joints is similar to that of loop joints, or more than. It seems that the use of wide joints is the possible methods in a construction field.

• 연구논문집
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• s.22
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• pp.21-26
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• 1992

Dynamic analysis is important in structural design of SCARA or articulated type industrial robots and is' usually done to main three axes. In this paper, robot arm dynamics was analyzed using FBD(free body diagram). Though the proposed scheme becomes complex as DOF(degree of freedom)increases, it allows to see types and directions of forces and moments acting on the body. Therefore, the strength analysis of robot arm can be done relatively easy in a case of either closed or open loop chain. This method can be used for obtaining dynamic simulation at off-line programming system and calculating required torques at joints at on-line system.