• 전기학회논문지
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• 제59권4호
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• pp.793-796
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• 2010

The equalizer compensates a signal distorted by transmission lines and amplifying stages, so the signal can have uniform characteristics over all frequency range. The equalizer in ODD(Optical Disc Drive) improves the stability of the extracted clock from a received signal and the readability of an inserted disc by suppressing noise and ISI(Inter-Symbol Inference). The length of marks-spaces and track pitch on discs becomes shorter as the recording density of an optical media is higher, which causes noise and ISI. And, the sensitivity about the fluctuation of physical systems is higher as the optical devices become more complicate. This paper proposes a method to select the coefficient of built-in equalizer of ODD in order to maintain the quality of signals against noise and ISI caused by system fluctuation.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.191-199
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• 1999

In designing the tracking system of an optical disc drive, it is first necessary to eliminate the undesired influence of any visible mechanical vibrations. In this paper a geometrical method to analyze the frequency response of an elastically supported planar rigid body has been presented. Using the theory of screw, a geometrical expression of a compliant transfer function which describes the effects of the locations of an applied force and observation on the response has been derived. Applying the substructure synthesis method, a technique to stabilize the tracking mechanical system has been presented with a numerical example.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.363-368
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• 2001

Studies on brake system recently are focused on braking performance, especially the consideration on safety of braking system in an extreme situation and reduction of vibration and noise during braking operation. The thermal crack and Judder from the friction between brake disc and pad can bring the threaten of passengers' safety in the end. Braking force comes from the change of kinetic energy to friction energy. Since heat energy is developed from here, the analysis on thermal stress and thermal strain can be the good data when selecting the material of brake pad and designing heat radiation holes on the disc and it will also be the data when designing the thickness of the disc. This paper is intended to show a creative design method by suggesting the thermal analysis data through FEM study and using shape design parameters.

• 품질경영학회지
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• 제42권4호
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• pp.563-578
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• 2014

Purpose: The purpose of this paper is integrated tolerance design process by advantages of engineering design and 6 sigma statistical tolerances design. Methods: Integrated tolerance design process can determine the goals by using engineer's experience and clarify tolerance by 6 Sigma statistical methods. Integrated design process can be applied by using non-linear simulations. Results: We applied integrated design process to the optical disc drive spindle motor and get good result. Conclusion: If this method is applied test method in the early stages of development, then Design can be reduced development time and cost.

• 자동차안전학회지
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• 제8권3호
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• pp.28-32
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• 2016

Braking system is directly related to the safety of a vehicle and the brake discs are essential part of the braking system. Due to the repeated frictional forces and torque during braking, brake discs are always works at high temperature and high pressure. Furthermore, the brake disc is one of major tuning components in aftermarket, the braking performance of the brake disc should be evaluated for establishing the certification standards of tuning components. This paper proposes the test method to evaluate the performance of tuning brake discs.

• 한국소음진동공학회논문집
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• 제18권10호
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• pp.1042-1048
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• 2008

Disc brake noise is an important customer satisfaction and warranty issue for many manufacturers as indicated by technical literature regarding the subject coming from Motor Company. This research describes results of a study to assess disk brake squeal propensity using finite element methods and optimal technique (Kriging). In this study, finite element analysis has been performed to determine likely modes of brake squeal. This paper deals with friction-induced vibration of disc brake system under contact friction coefficient. A linear, finite element model to represent the floating caliper disc brake system is proposed. The complex eigen-values are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model. In this paper, Kriging from among the meta-modeling techniques is proposed for an optimal design scheme to reduce the brake squeal noise.

• 소음진동
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• 제10권1호
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• pp.123-128
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• 2000

This paper describes the optimization of the hexagonal array transducer using finite element method. The transducer consists of the disc type sensors. Three dimensional beam patterns of each element and the array transducer are analysed using the finite element code ATILA. Beam patterns were analyzed for the disc type transducer. To optimize beam patterns of the array transducer, Chebyshev polynomial weight is applied to each element. In case of applying optimized weight, a 30 degree width beam pattern is presented at 10kHz. This paper also includes the effect of rubber filling material instead of using the water inside the transducer array.

• Applied Biological Chemistry
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• 제35권5호
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• pp.395-398
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• 1992

Griseofulvin의 구조활성상관연구에서 6'-methyl기와 4'-oxo기가 생물활성에 있어서 중요한 인자라는 것이 예견되어, 6'-methyl기(基)를 phenyl기(基)로 치환한 6'-phenylgriseofulvin을 diels-alder부가환화로 합성하고 Botrytis allii 및 B. cinerea에 대한 항균활성을 paper disc 법으로 연구하였다. 6'-Phenylgriseofulvin은 $25\;{\mu}g/disc$에서 높은 항균활성을 나타냈다.

• 한국해안·해양공학회논문집
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• 제26권6호
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• pp.359-366
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• 2014

본 연구에서는 버터플라이밸브의 고유 유량 특성을 개선하기 위해 회색 관계분석을 이용한 디스크 형상 최적화 방안을 도입하였다. Class 150의 200A 버터플라이밸브에 대해 적용하여 그 유용성을 확인하였다. 부가물 형상 파라미터의 영향 분석을 위해 직교 배열을 이용한 실험계획법을 실시하였으며, 파라미터의 영향을 회색 관계 분석과 평균 분석을 이용하여 분석하였다. 최적화를 위한 목적함수는 유량 계수를 선정하였으며, 기존 디스크 모델과 부가물 부착 모델에 대해 유동 해석을 수행하였다. 회색 관계 등급을 이용하여 평균 분석을 실시하였으며, 그 결과를 토대로 최적 형상을 결정하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권5호
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• pp.696-704
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• 2009

In this paper, the flow characteristics through an industrial safety relief valve used to protect the crankcase room in a large-sized marine engine have been numerically investigated using the moving-mesh strategy. With the room pressure higher than the cracking one, the spring-loaded disc becomes open and then the air in the room blows off into the atmosphere, resulting in the reduction of the room pressure and then the shutoff of the disc. Numerical simulations are performed on the compressible air flow through the relief valve (${\phi}160mm$) with the initial room pressure (0.11 bar or 0.12bar) higher than the cracking one (0.1 bar). The numerical method has been validated by comparing the results with the empirical ones. Results show that the disc motion and flow characteristics can be successfully simulated using the moving-mesh strategy and depend strongly on the spring stiffness and the flow passage shape. With increasing spring stiffness, the maximum disc displacement decreases and thus the total disc-opening time also decreases. In addition, the flow passage shape makes a significant effect on the velocity and direction of the flow.