• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.338-343
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• 2015

In order to avoid the interference from existing narrowband communication systems, this paper proposes a compact band-notched UWB (ultra wideband) antenna with size of $12mm{\times}22mm{\times}1.6mm$. Transmission line model is applied to analyzing wide impedance matching characteristic of the modified base antenna, which has a gradual stepped impedance feeder structure. The proposed antenna realizes dual band-notched function by combining two biased T-shaped parasitic elements on the rear side with a window aperture on the radiation patch. The simulation current distributions of the antenna reflect resonant suppression validity of the two methods. In addition, the measured radiation characteristics demonstrate the proposed antenna prevents signal interference from WLAN (5.15-5.825GHz) and WiMAX (3.4-3.69GHz) effectively, and the measured patterns show the antenna omnidirectional radiation in working frequencies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1023-1032
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• 1995

The multiple cooperating robot system plays an important role in the research of modern manufacturing system as the emphasis of production automation is more on the side of flexibility than before. While the kinematic and dynamic analysis of a single robot is performed as an open-loop chain, the dynamic formulation of robot in a multiple cooperating robot system differs from that of a single robot when the multiple cooperating robots form a closed kinematic chain holding an object simultaneously. The object may be any type from a rigid body to a multi-joint linkage. The mobility of the system depends on the kinematic configuration of the closed kinematic chain formed by robots and object, which also decides the number of independent input parameters. Since the mobility is not the same as the number of robot joints, proper constraint condition is sought. The constraints may be such that : the number of active robot joints is kept the same as mobility, all robot joints are active and have interrelations between each joint forces/torques, two robots have master-slave relation, or so on. The dynamic formulation of system is obtained. The formulation is based on recursive dual-number screw-calculus Newton-Eulerian approach which has been used for single robot analysis. This new scheme is recursive and compact symbolically and may facilitate the consideration of the object in real time.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.27-31
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• 2010

It is a well known fact that the LCD and Semiconductor Devices are a central part of IT industry which is important in the present and the future. But the biggest problem of Semiconductor and LCD manufacturing is maintaining a cleaning room environment. For this reason, the soft X-ray type Ionizer was used as the electrostatic reducer device, which protects damage of the product against electrostatic discharge in the manufacturing process. Therefore it is a essential important factor during Semiconductor and LCD production process. But the soft X-ray has a intrinsic problem with harmful to human being in case of soft X-ray exposure. That's reason we have the research to solve above problem and made an apparatus that it was covered with shielding structure to protect X-ray radiation to outside. And besides, it has a possibility to eliminate the charged electrostatic in the narrow space through the slot for Ion emissions with dual soft X-ray sources on the both side. It is also not make the particles from itself when it has been operated.

• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.149-154
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• 2014

A new CMOS analog design methodology using an independently optimized self-cascode (SC) is proposed. This idea is based on the concept of the dual-workfunction-gate MOSFETs, which are equivalent to SC structures. The channel length of the source-side MOSFET is optimized, to give higher transconductance ($g_m$) and output resistance ($r_{out}$). The highest $g_m$ and $r_{out}$ of the SC structures are obtained by independently optimizing the channel length ratio of the SC MOSFETs, which is a critical design parameter. An operational amplifier (OPAMP) with the proposed design methodology using a standard digital $0.18-{\mu}m$ CMOS technology was designed and fabricated, to provide better performance. Independently $g_m$ and $r_{out}$ optimized SC MOSFETs were used in the differential input and output stages, respectively. The measured DC gain of the fabricated OPAMP with the proposed design methodology was approximately 18 dB higher, than that of the conventional OPAMP.

• Journal of Korean Association for Spatial Structures
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• v.5 no.2 s.16
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• pp.47-55
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• 2005

The method to form the space of the pneumatic structures by internal pressure is classified greatly as the dual type with the nlty type. The shape of the pneumatic structures consists of the curved surface under uniform tension not greatly to be deformed by the design load and stress must not be concentrated also. Therefore, In this study, we have done the structural analysis of the unity typed pneumatic structures by the NASS which is the program for nonlinear analysis. The analytic model is a rectangular pneumatic membrane structures which have four side fixed edges. And we have done the nonlinear incremental analysis considering the orthotropic material.

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.7-13
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• 2014

In order to enable fail-safe operation the electro-hydrostatic actuators can be dualized. When a symmetrical actuator is combined in series with an asymmetrical actuator with single rod cylinder, the flow rates of their cylinders are unmatched. If their position controller has same configuration, one of their pumps can supply too much flow rate under particular load conditions, which should be bypassed into low pressure side e.g. by a relief valve. In this paper it is shown how the hydraulic circuit for the asymmetrically combined electro-hydrostatic actuator can be designed without sacrificing power consumption.

• Journal of Welding and Joining
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• v.32 no.1
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• pp.87-92
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• 2014

Recently, use of thick Al 5083 plate has increased in production of LNG storage tank. In general, multi-pass welding has been used to achieve sufficient penetration in thick plate welding. High current welding which enables high deposition and deep penetration is preferred in thick plate welding because the increase of number of pass increases manufacturing cost and formation of weld defect. In this study, welding characteristics according to various Ar/He shielding gas composition was investigated in high current MIG welding. The bead-on-plate welding and V groove welding were conducted on Al 5083 alloy with a thickness of .25 mm. The effect of shielding gas composition on bead shape was evaluated and proper shielding gas composition was proposed. Also arc stability was examined under selected shielding gas composition. One side-one pass welding experiments were conducted for V groove specimen with a thickness of 25 mm. Mechanical properties and hardness profiles were measured for the V groove specimens.

• Journal of Haehwa Medicine
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• v.10 no.2
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• pp.41-71
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• 2002

The purpose of this paper is to infer the effects on the separation of pharmacy and clinic in the oriental medicine, the unification of the medical system and the medical and pharmaceutical system, etc. from the conflict between the oriental medicine doctors and the pharmacists in 1990s. The results are as follows. 1. The oriental medicine doctors, the pharmacists and a private organization(Citizen's Coalition for Economic Justice) found the solution in the conflict nongovernmently as the government failure. 2. The conflict brought about directly the separation of pharmacy and clinic in the western medicine but the opposite effect in the oriental medicine. 3. The conflict brought about the continuance of the dual medical system. 4. In the part of the medicine, citizen's organizations stated to play their part in the dispute. This is a positive side in the conflict. 5. The conflict contributed to democratization in the medical market and the medical world.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2053-2058
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• 2004

The pressurized light water cooled, medium power (330 MWt) SMART (System-integrated Modular Advanced ReacTor) has been under development at KAERI for a dual purpose : seawater desalination and electricity generation. The SMART design verification phase was followed to conduct various separate effects tests and comprehensive integral effect tests. The high temperature / high pressure thermal-hydraulic test facility, VISTA(Experimental Verification by Integral Simulation of Transient and Accidents) has been constructed to simulate the SMART-P (the one fifth scaled pilot plant) by KAERI. Experimental tests have been performed to investigate the thermal-hydraulic dynamic characteristics of the primary and the secondary systems. Heat transfer characteristics and natural circulation performance of the PRHRS (Passive Residual Heat Removal System) of SMART-P were also investigated using the VISTA facility. The coolant flows steadily in the natural circulation loop which is composed of the steam generator (SG) primary side, the secondary system, and the PRHRS. The heat transfers through the PRHRS heat exchanger and ECT are sufficient enough to enable the natural circulation of the coolant.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.505-517
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• 2016

The structural integrity of a dual-purpose metal cask currently under development by the Korea Radioactive Waste Agency (KORAD) was evaluated, through numerical simulations and a model test, under high-speed missile impact reflecting targeted aircraft crash conditions. The impact conditions were carefully chosen through a survey on accident cases and recommendations from literature. In the impact scenario, a missile flying horizontally hits the top side of the cask, which is freestanding on a concrete pad, with a velocity of 150 m/s. A simplified missile simulating a commercial aircraft engine was designed from an impact loade-time function available in literature. In the analyses, the dynamic behavior of the metal cask and the integrity of the containment boundary were assessed. The simulation results were compared with the test results for a 1:3 scale model. Although the dynamic behavior of the cask in the model test did not match exactly with the prediction from the numerical simulation, other structural responses, such as the acceleration and strain history during the impact, showed very good agreement. Moreover, the containment function of the cask survived the missile impact as expected from the numerical simulation. Thus, the procedure and methodology adopted in the structural numerical analyses were successfully validated.