• KIEE International Transactions on Electrophysics and Applications
• /
• v.4C no.4
• /
• pp.155-159
• /
• 2004

This work reports the theoretical and experimental investigations of capillary bust valves to regulate liquid flow in microchannels. The theoretical analysis uses the Young-Laplace equation and geometrical considerations to predict the pressure at the edge of the valve opening. Numerical simulations are employed to calculate the meniscus shape evolution while the interface is pinned at the valve edge. Microchannels and valves are fabricated using soft lithography. A wafer-rotating system, which can adjust the driving pressure by rotational speed, induces a liquid flow. Experimentally measured valve-bursting pressure agrees with theoretical predictions.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.806-808
• /
• 1992

This paper describes a buried-island SOI MOSFET structure which can reduce the edge channel effect by improving the interface properties at the side wall of active island and by reducing the strength of electric field applied at the upper corner of the side wall from the gate. Also, the buried-island SOl structure can obtain the uniform thickness of SOl film. The buried-island structure can be achieved by Zone- Melting-Recrystallization of polysilicon and polishing. Both simulated and experimental results show that the buried-island SOl NMOSFET has less edge channel effect than the conventional SOl NMOSFET using LOCOS or mesa isolation technique.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.11a
• /
• pp.227-233
• /
• 2003

In paper, we present design and implementation of MPLS based VPN with QoS capabilities. We propose a design architecture of an edge router for MPLS based VPN with QoS capabilities in backbone network. We design functional blocks, interface specifications, detail routing and forwarding information based structure, and packet forwarding engine for the purpose of implementation of an edge router, We extend bgp-4 software for implementation differentiated service packet forwarding schemes in MPLS based VPN.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.632-637
• /
• 2004

In the shrink or press fitted shaft such as railway axle, fretting can occur by cyclic stress and micro-slippage due to local movement between the shaft and the hub. When the fretting occurs in the press fitted shaft, the fatigue strength remarkably decreases compared with that of without fretting. In this paper, the analysis of contact stresses in a press fitted shaft in contact with a hub was conducted by finite element method and the micro-slip according to the bending load was analyzed. It is found that the largest stress concentration and maximum slip amplitude of shrink fitted shaft are found at the edge of the interface and the distribution of contact stresses at the contact edge has largely influenced and coefficient of friction.

• Korean Journal of Crystallography
• /
• v.12 no.3
• /
• pp.166-170
• /
• 2001

Dopants implanted in silicon substrate affect the reaction between cobalt and silicon substrate. Phosphorous, unlike boron and arsenic, suppressing the reaction between cobalt and silicon induces CoSi formation during a low temperature thermal treatment instead of CoSi₂formation. The CoSi layer should move to the silicon substrate to fill the vacant volume that is generated in the silicon substrate due to the silicon out-diffusion into the cobalt/CoSi interface. The movement of CoSi at gate sidewall spacer region is suppressed by a cohesion between gate oxide and CoSi layers, resulting in a void formation at the gate sidewall spacer edge.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.3
• /
• pp.15-22
• /
• 2008

Applications of bonded dissimilar materials such as integrated circuit(IC) packages, ceramics/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edge in bonded joints of dissimilar materials. In order to investigate the IC package crack propagating from the edge of die pad and resin, the fracture parameters of bonded dissimilar materials and material properties are obtained. In this paper, the thermal stress and its singularity index for the IC package were analyzed using 2-dimensional elastic boundary element method(BEM). From these results, crack propagation direction and path by thermal stress in the IC package were numerically simulated with boundary element method.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.132-132
• /
• 2011

The sheet resistance (Rs) of undoped GaN films on AlN/c-plane sapphire substrate was investigated in which the AlN films were grown by R. F. magetron sputtering method. The Rs was strongly dependent on the AlN layer thickness and semi-insulating behavior was observed. To clarify the effect of crystalline property on Rs, the crystal structure of the GaN films has been studied using x-ray scattering and transmission electron microscopy. A compressive strain was introduced by the presence of AlN nucleation layer (NL) and was gradually relaxed as increasing AlN NL thickness. This relaxation produced more threading dislocations (TD) of edge-type. Moreover, the surface morphology of the GaN film was changed at thicker AlN layer condition, which was originated by the crossover from planar to island grains of AlN. Thus, rough surface might produce more dislocations. The edge and mixed dislocations propagating from the interface between the GaN film and the AlN buffer layer affected the electric resistance of GaN film.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.167-170
• /
• 2001

A three dimensional adaptive finite element analysis algorithm is developed. In the method, the edge elements are used for field analysis, and the local error. In each element is estimated from the fact that the magnetic field should satisfy. The continuity condition at the interface of the two adjacent elements. Based on the estimated error, the elements which are considered to have big error are divided into several elements using the bisection method. The effectiveness of the developed algorithm is proved through numerical examples.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.40 no.2
• /
• pp.207-216
• /
• 1991

In the case that the robot manipulator should respond to the variance and uncertainty of the environment in performing preforming precision tasks, it is indispensable that the robot utilizes the various sensors for intrlligence. In this paper, the robot force control method is implemented with a force/torque sensor, two personal computers, and a PUMA 560 manipulator for performing the various application tadks. The hybrid position/force control method is used to control the force and position axis separately. An interface board is designed to read the force/torque sensor output into the computer. Since the two computers should exchange the information quickly, a common memory board is designed. Before the algorithms of application tasks are developed, the basic force commands must be supplied. Thus, the MOVE-UNTIL command is used at the discrete time instant and, the MOVE-COMPLY is used at the continuous time instant for receiving the force feedback information. Using the two basic force commands, three application algorithms are developed and implemented for edge-following, insertion, and grinding tasks.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.1 no.2
• /
• pp.117-124
• /
• 1993

This study is concerned with an application of the boundary element method on the crack problem. The stable and efficient analysis method of two dimensional elastostatic stress intensity factor on the mode I deformations is established from the result o stress analysis for the center cracked plates. In order to precisely analyse, The subelements of quadratic element, singular elements on the crack tip and interface and division into regions are applied to elastic stress. The usefulness of the method has been tested with a center cracked plates, a double edge cracked plate and a single edge cracked plate, and the results have turned out to be fairly satisfactory.