• Applied Science and Convergence Technology
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• v.27 no.1
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• pp.14-18
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• 2018

In order to understand the mechanism of the synthesis of particles using a plasma torch, it is necessary to understand the reaction mechanisms using a computer simulation. In this study, we have developed a simulation method to combine the Lagrangian scheme to follow microparticles and a nodal method to treat nanoparticles categorized with different particle sizes. The Lagrangian scheme includes the Coulomb force which affects the dynamics of larger particles. In contrast, the nodal method is adequate for the nanoparticles because the charge effect is negligible for nanoparticles but the number of nanoparticles is much larger than that of microparticles. This method is helpful to understand the dynamics and growth mechanism of micro- and nano-powder mixture observed in the experiment.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.113-122
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• 2014

The objective of the paper is to clarify a methodology based on the use of the existing component mode synthesis methods for the case of two damped substructures which are coupled through a linking viscoelastic flexible substructure and for which the structural modes with free geometrical interface are used for each main substructure. The proposed methodology corresponds to a convenient alternative to the direct use either of the Craig-Bampton method applied to the three substructures (using the fixed geometric interface modes) or of the flexibility residual approaches initiated by MacNeal (using the free geometric interface modes). In opposite to a geometrical interface which is a topological interface on which there is a direct linkage between the degrees of freedom of substructures, we consider a physical flexible interface which exists in certain present technologies and for which the general framework linear viscoelasticity is used and yields a frequency-dependent damping and stiffness matrices of the physical flexible interface.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.11-17
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• 1998

In this paper, the synthesis procedufe of impedance matching network is presented for broad-band microwave amplifier design, whereby amplifier operating in the octave bandwidth is designed and fabricated in detail. The transfer function of the matching netowrks is synthesized by chebyshev approximation and element values for the networks of specified topology are calculatd for various MILs and ripples. After the transistor is modeled by negative-image device model, the synthesis procedure for matching networks is applied to broad-band amplifier design which has electrical performance of about 12dB gain in 4 to 8GHz range. Experimental results obtained from the fabricated amplifier are shown to approach the electrical performance designed in the given frequency range. Construction of the impedance matching networks by transfer function synthesis is very useful method for the design of broad-band microwave amplifiers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.275-278
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• 2001

Research on the forced vibration control of a flexible GFR composite beam using $\mu$-synthesis is performed on this paper. Modal analysis method and modal coordinates are introduced to obtain the state equations of the structural system. Using these equations, Robust control algorithm using $\mu$-synthesis is adopted to suppress the forced vibration of a flexible beam since the designed controller can considered plant uncertainty and external disturbance. Constant disturbance which is generated by shaking the flexible beam as I's natural frequency is effectively rejected by a PZT actuator. Simulations and experiments are carried out with the designed controller and effectiveness of forced vibration suppression strategy is verified by results.

• Journal of Power System Engineering
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• v.5 no.4
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• pp.24-30
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• 2001

The substructure synthesis method(SSM) is developed for overcoming disadvantages of the Finite Element Method(FEM). The concept of the SSM is as follows. After dividing a whole structure into several substructures, every substructures are analyzed by the FEM or experiment. The whole structure is analyzed by using connecting condition and the results of substructures. The concept of the transfer stiffness coefficient method(TSCM) is based on the transfer of the nodal stiffness coefficients which are related to force vectors and displacement vectors at each node of analytical mode1. The superiority of the TSCM to the FEM in the computation accuracy, cost and convenience was confirmed by the numerical computation results. In this paper, the author suggests an efficient vibration analysis method of structures by using the TSCM and the SSM. The trust and the validity of the present method is demonstrated through the numerical results for computation models.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.729-737
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• 1998

In this paper, using $\mu$ synthesis algorithm with structured uncertainty, we design controller and apply it for the Two-Inertia resonance(TMS: Two Mass Spring) system. The TMS system is one of the simplest models which generate a torsional vibration. In this system, it is required to design a controller achieving the control performance while suppressing the torsional vibration. Furthermore, when vibration frequency for the system is varying by reason of parameter variations, we should consider parameter variations in controller design. Then, we design two other controller schemes of the PI controller and the standard $H_{\infty}$ controller and compare these controllers with the controller designed by the $\mu$ synthesis robust control method by using simulations and experiments.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1833-1840
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• 1993

An efficient vibration analysis method, Component Mode Synthesis(CMS), for an exhaust system with bellows is presented. Analyses are performed for two types of bellows, where characteristics of vibration modes affecting idle shake and interior noise of a vehicle are examined. Also analyzed are the contributions of an exhaust and engine mounting system to the idle shake and interios noise. Comparison between the analysis and test is in good agreement, hence the CMS method is shown to be efficient and valid.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.135.1-135.1
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• 2014

Silicon nanoparticles can be synthesized in a standard radio-frequency glow discharge system at low temperature (${\sim}200^{\circ}C$). Plasma synthesis of silicon nanoparticles, initially a side effect of powder formation, has become over the years an exciting field of research which has opened the way to new opportunities in the field of materials deposition and their application to optoelectronic devices. Hydrogenated polymorphous silicon (pm-Si:H) has a peculiar microstructure, namely a small volume fraction of plasma synthesized silicon nanoparticles embedded in an amorphous matrix, which originates from the unique deposition mechanism. Detailed discussion on plasma synthesis of silicon nanoparticles, growth mechanism and photovoltaic application of pm-Si:H will be presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.182-186
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• 2006

An efficient dynamic response analysis mettled of structures supported by resilient mounts is presented by using the structural synthesis method in frequency domain and time domain. As a numerical example, a mount-deck system is considered. Through numerical simulations, the validity of the presented method is verified by comparison of the results with those of the 'traditional' analysis method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.82-89
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• 1996

In this study, to choose the drilling m/c with analysis model for dynamic design of machine tool strctures, are used substucture syntheis method for reduction to degrees of freedom of dynamic model and analysis evaluation of substructures The dynamic factors of substurctures are examined by substructure synthesis method. And that dynamic design of structures for energy balancing are performed. The computer program for calculated of the dynamic and energy distribution analysis was developed. Result of numerical analysis by developed program obtained to conclusion as following. The design of machine tool structures by dynamic avoid the resonances, and are known to considered based on the energy balancing. These methods can be used effectively for the performance evaluation, design modification and improvement of dynamic performance evaluation, design modification and improvement of dynamic performance of machine tools.