• Journal of IKEEE
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• v.24 no.2
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• pp.409-418
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• 2020

In this paper, an integrated optical, evanescent-wave biosensor utilizing a multimode interferometer based on a Si₃N₄ rib-optical waveguide consisting of the Si/SiO₂/Si₃N₄/SiO₂ stacked structure was described. The theoretical background of the multimode interferometer was reviewed, and the structure and design process were presented through numerical computational analysis. We analyzed how the dimension (length, width) of the multimode interferometer affected the sensor performance. It has been confirmed through computational analysis that the changes in the refractive index of an analyte greatly affect the mode pattern formation position and output optical power of a multimode interferometer, and proved that this principle could be applied to integrated-optic biosensor.

• Composites Research
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• v.19 no.2
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• pp.13-19
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• 2006

In this paper, parametric study was carried out to design sandwich structures for EDM machines controlling stacking sequence, stacking thickness of composites and rib configuration. Sandwich structures which are dealt with in this paper are composed of fibre reinforced composite for skin material and foam or resin concrete for core materials. The sandwich column has cruciform rib to enhance bending stiffness of the structure and the bed has several vertical ribs to resist the normal forces and vibration. The design parameters such as rib thickness and stacking sequence were controlled to enhance the system robustness. Finite element analysis was also carried out to verify the variation of static and dynamic stiffness of the structures according to the variation of the parameters. Vibration tests were performed to verify the natural frequencies and damping ratios of the manufactured composite structures. The appropriate shape and configuration conditions for micro-EDM machine structures are proposed.

• Journal of KIEE
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• v.11 no.1
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• pp.41-45
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• 2001

The addressing time should be reduced by modifying cell structure and/or driving method in order to replace the dual scan system by single scan and increase the luminance in large ac plasma display panel(PDP). In this paper, the effects of the dielectric layer thickness and the barrier rib height on the addressing time of ac PDP are investigated. It is found out that the addressing time was decreased with decreasing thickness of dielectric layer on the front glass and thickness of white dielectric layer on the rear glass. The decreasing rate were 160ns/10${\mu}{\textrm}{m}$ and 270nsd/10${\mu}{\textrm}{m}$, respectively. Also in case of decreasing the height of barrier rib, addressing time was decreased at the rate of 550ns/10${\mu}m$.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.108-115
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• 2006

A hydraulic breaker is widely utilized for many civil engineering areas for the purpose of destroying objects such as rocks, concrete, or road. However, since the high-level noise and vibration by a hydraulic breaker is one of the major sources of environmental noise and recently the environmental regulations on construction equipments are also getting more strengthened, in order to solve such problems, it is certainly necessary to design and develop a hydraulic breaker with low noise and low vibration. This research is to understand the noise characteristics through the noise test and acoustic analysis of the bracket housing in a hydraulic breaker and to identify the element part to be modified based on the result of the element contribution analysis. An improved breaker model including X-typed rib shows the result of low-noise level within target frequency band compared with a commercial breaker model.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.65-72
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• 2013

This paper describes a finite element analysis (FEA) of the body frame of a subsea robot, Crabster200 (CR200). CR200 has six legs for mobility instead of screw type propellers, which distinguishes it from previous underwater robots such as remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs). Another distinguishing characteristic is the body frame, which is made of carbon fiber reinforced plastic (CFRP). This body frame is designed as a rib cage structure in order to disperse the applied external loads and reduce the weight. The frame should be strong enough to support many devices for exploration and operation underwater. For a reasonable FEA, we carried out specimen tests. Using the obtained material properties, we performed a modal analysis and FEA for CR200 with a ready posture. Finally, this paper presents the FEA results for the CFRP body frame and the compares the characteristics of CFRP with conventional material, aluminum.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.613-616
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• 2002

Luminance and contrast ratio is one of the most fundamental and important parameters of plasma display panel. Understanding the effects of cell design parameters on the display and background luminance is inevitable for improving the contrast ratio. We report the experimental results on the relationships between cell parameters and contrast ratio of the ac PDP driven by ADS scheme. It was found that the contrast ratio is the most significantly affected by rib height and optimum range of the rib height simultaneously affects the facing discharge during the reset periods, diffusion loss of plasma and shadowing of the visible light emitted from phosphor.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.75-78
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• 2002

Difference in the structure of AC PDP cells makes the cells have various discharge characteristics. Therefore, a ramp-reset must be adjusted for the stable driving of AC PDP. If any ramp-reset can reduce the difference in discharge characteristics between cells, the conditions of the address discharge could become almost the same. It is very important to understand these to design a good driving waveform. In this paper, we proved the mentioned facts with the change of barrier rib heights.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.119-122
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• 2000

We proposed a novel mode shape converter (MSC) that can effectively reduce the coupling loss between polymer rib waveguide and single mode fiber. The double-nb geometry that was used in the novel MSC converted an elliptical mode to circular mode and an circular mode to elliptical mode. This structure can be easily realized by using the typical fabrication process for polymer wavegUide. Simulation using a three dimensional beam propagation method showed that the novel MSC has a coupling loss of 0.079 dB/facet and total lllsertioll loss of less than 0.2 dB. .2 dB.

• Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.8-14
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• 2013

When launch vehicles are manufactured, one of the key points is a design of lightweight structure for reducing costs. Isogrid structure was designed to solve this topic, and many researches were carried out about buckling load because compression load is mainly applied to them. Recently, many studies are also being carried out about FEM model geometry of isogrid structure. The reason is that isogrid structure depends on size of ribs so it is difficult to modify about small changes in rib pattern. In this study, 1/8 model of cylindrical isogrid structure model was developed to analyze buckling behavior. Through parameter study, buckling analysis were performed to analyze buckling load and buckling mode depending on size of ribs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1293-1296
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• 2007

In this paper, present a finite element method to reduce vibration of a cylindrical structure by avoiding resonance between motor and structure. To analysis the modes of structure, some different FE models (different places and combinations of ribs) of the structure with free-free condition were built and compared.