• Proceedings of the KWS Conference
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• 2002.10a
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• pp.791-797
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• 2002

This paper introduces the partial melting process for solder application and characterization of its feasibility using Sn-Ag, and Sn-Cu solder alloys. ill order to show that the liquid phase in the semi-liquid state maintains the similar wettability as single-phase liquid, the wetting balance tests are conducted with varying temperatures and compositions. Also, as a new soldering technology, the microstructural and mechanical test were investigated. The results from this research indicate that the partial melting can yield satisfactory sider joints as long as the liquid phase acquires sufficient chemical activity. At a condition where the partial melting is effective, a direct correlation between the wettability and the surface tension is found to exist.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.227-229
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• 2003

We present a process for printing active matrix displays. In this process, transistors are fabricated using soluble semi-conducting and conducting materials. Accurate definition of the transistor channel and other circuit components is achieved by direct inkjet printing combined with surface energy patterning. We present results on our 4,800 pixel, 50 dpi, active matrix displays.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.172-175
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• 2001

This paper presents a new energy function reflecting the damping effect in multi-machine power systems. The Lyapunov direct method provides precise and rigorous theoretical backgrounds for stability analysis of nonlinear systems. Incorporating damping effects into accurate estimates of the domain of attraction, which is a minor but crucial point, has been attempted with long history to yield partial success for single machine systems. In this paper, the damping-reflected energy function presented in the previous work has been generalized for application to multi-machine systems. The generalized energy function is tested for the WSCC 9-bus system to show the semi-negativeness of its time derivative.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.718-723
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• 2004

The insertion loss of a noise barrier comes from the effects of diffraction, transmission loss, absorption coefficient and attenuation by direct propagation. The noise level after the noise barrier, differs reatly from the diffraction on the upper part of the barrier. Maekawa, furze and Anderson presented a empirical formula for calculating the diffraction of a semi infinte screen shaped noise barrier. In this syudy, Noise reduction performance software was developed for the proper design and assessment of new plastic barrier . Predicted sound pressure level from using the software is compared with the site-measurement results to verify the noise reduction performance and feasibility of prediction software for insertion loss of noise barrier.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1087-1090
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• 2008

This paper presents the electro-luminescence (EL) display lamp which is patterned on a curved surface by the pad printing method. The printing methods, including the gravure, screen, flexo, inkjet, and pad printing, have an advantage of one-step direct patterning. However, in general, the printing and semi-conductor process, except pad printing method, cannot be applied for patterning on a curved surface. Thus, in this paper, we used pad printing method for patterning an EL display lamp on a curved surface. The EL display lamp consists of 5 layers: Bottom electrode; Dielectric layer; Phosphor; Transparent electrode; Bus electrode. Finally, we printed EL display lamp on a dish, which has a radius of curvature 80mm. The EL display lamp was driven at AC 200V of 1kHz.

• Environmental Engineering Research
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• v.11 no.1
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• pp.28-32
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• 2006

The degradation of atrazine was explored using UV alone, $H_2O_2/UV$, oxalate/UV and oxalate-assisted $H_2O_2/UV$. The addition of oxalate to the $H_2O_2/UV$ (oxalate-assisted $H_2O_2/UV$) process was the most effective method for the degradation of atrazine. The overall kinetic rate constant was split into the direct oxidation due to photolysis and that by the radicals from hydrogen peroxide or oxalate. In semi-empirical terms, the initial concentration of hydrogen peroxide had a greater contribution than that of oxalate for atrazine oxidation.

• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.1-6
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• 1997

This paper describes the design of a network interface controller (NIC) chip which is to be used to support a novel adaptive virtual cut-through routing method for parallel compute systems with direct (i.e., point-to-point) interconnection networks. The NIC chip is designed to provide the interface between a processing node constructed from commercially available microprocessors and another custom-designed router chip, which in turn performs the actual routing of packets to their respective destinations. The NIC, designed using a semi-full-custom VLSi design technique outperform traditional wormhole routing with a minimal amount of hardware overhead. The NIC design has been fully simulated and laid out using a 0.8$\mu\textrm{m}$ CMOS process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.281-291
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• 1999

A computer code based on a node equation method has been developed for the analysis of pipe network. Both data structure and object-oriented programming technique are used for pipe and node modelling, in which simplification process is applied to complicated and large pipe network. The semi-direct solver, ILU-CGS, improves greatly both the accuracy and the rate of convergence. The computational result of high-pressure pipe network of city gas in Taegu shows the good agreement with the real data.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.197-201
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• 2002

양식장 해양 레져, 항구 등에서 Calm Sea Area을 필요로 한다. 착저식은 소파효율은 좋으나 해수순환을 방해하여 환경에 좋지 않은 영향을 미치게 된다. 또한 설치비용이나 설치 해역의 한계가 있다. 따라서 이러한 한계들을 극복하기 위해서 부유식 소파구조물을 채택하였다. 본 논문에서는 몇 가지 소파공의 크기를 가지는 반 투과성 부유 소파구조물을 무한수심에서 유체역학적 특성과 소파효율을 계산하였다. 산란문제와 발산문제를 해결하기 위해 선형 포텐셜이론을 사용하여 구조물의 유체역학적 특성을 계산하였다. 적절한 소파공의 크기를 결정함에 따라 소파효율을 향상시킬 수 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.938-948
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• 2001

In this paper, we present an exoskeletal haptic device named SKK Hand Master. This device is directly driven linkages actuated with small ultrasonic motors. By adopting ultrasonic motors that have advantageous features useful for cybernetic actuators, a compact haptic device containing whole driving packages can be established without additional power transmissions such as tendons. Methods for measuring joint postures and joint torques are developed and a new control strategy called PWM/PS is proposed to overcome intrinsic disadvantages such as hysteresis. Issues regarding design and construction of the device are addressed and several results of experiments for the evaluations of performance are included.