• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.225-228
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• 2010

In this paper, the present status of research, development, and required technologies for the thermal barrier type dual-pulse rocket motor of the advanced countries was analysed. The result of the conceptual design of the forward or backward ignition systems was also demonstrated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.92-95
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• 2012

The dual pulse rocket motor is a pressure vessel containing two pulse grains separated by a pulse separation device such as a fragile bulkhead. One of the important things in this systems is case insulation design using the excellent materials in the 1st stage pulse motor. We investigated manufacturing process of fabric/EPDM chamber insulations in order to protect the 1st stage pulse motor case with high intensity gas flow. Simulation motor connected with extension tube having FRP disc was designed to study ablation characteristics of insulation.

• Journal of Applied Reliability
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• v.15 no.2
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• pp.124-130
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• 2015

A stress-strength analysis is used to assess the reliability of a multi-pulse rocket motor system. Main stress is found to be thermal during explosion and the distribution is obtained by simulation. The strength distribution is derived from the results of actual specimen tests. The failure rate of barrier type pulse separation device is estimated.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.5
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• pp.101-110
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• 2010

Dual pulse rocket motor is a solid motor with two grains separated by a bulkhead and rupture disc. The elasto-plastic explicit dynamic analysis for the rupture disc was conducted by finite element method. The effect of the slit geometry of a rupture disc was parametrically analyzed in terms of rupture time and shape. The results can be used to control the rupture pressure by changing the slit geometry of rupture disc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.261-264
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• 2010

Dual Pulse Rocket Motor is a solid rocket motor with two grains separated by a bulkhead and rupture disc. The elasto-plastic explicit dynamic analysis of rupture disc was conducted by the finite element method. The effect of the slit geometry of rupture disc with radial slit was parametrically analyzed in terms of rupture time and shape. The results can be used to control the rupture pressure by changing the slit geometry of rupture disc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.105-112
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• 2010

Dual Pulse Rocket Motor is a solid rocket motor with two grains separated by a bulkhead and rupture disc. The elasto-plastic explicit dynamic analysis of rupture disc was conducted by finite element method. The effect of the slit geometry of a rupture disc was analyzed for rupture time and shape by the parametric study. The results can be used to control the rupture pressure by the change the slit geometry of a rupture disc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.481-487
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• 2011

This paper provides a comparison between finite element analysis results and test data of rupture disc. Rupture disc is safety device of high pressure equipment. Rupture disc of solid rocket motor is a device to control rupture pressure. Rupture discs were made of AISI 316L. By the elastic-plastic analysis, the stress limit of rupture discs were compared to the test results. The results can be used to control the rupture pressure by the change of the disc size.

• Journal of the Korea Society of Computer and Information
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• v.27 no.2
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• pp.163-170
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• 2022

Currently, as the number of families living with companion animals increases, the demand for information about the health status of companion animals has increased. As the demand for this increases, there is a need for a method to measure respiration and pulse in companion animals. Considering the characteristics of hairy companion animals, we want to measure respiration and pulse signals using BCG, which is different from adsorption ECG. Since this BCG method is made by mixing respiration and pulse signals into one signal, it is necessary to separate the respiration signal waveform and the pulse signal waveform from one signal waveform. In this paper, a wearable device for BCG measurement was implemented to measure the signal, and a method of separating the signal input from the BCG wearable device into a respiration signal and a pulse signal was proposed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.1-7
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• 2016

With a collimated $CO_2$ laser beam, the bidirectional current switching was realized in a two-terminal electronic device based on a highly resistive vanadium dioxide($VO_2$) thin film. A $VO_2$ thin film was grown on a $Al_2O_3$ substrate by a pulsed laser deposition method. For the fabrication of a two-terminal electronic device, the $VO_2$ thin film was etched by an ion beam-assisted milling method, and the $VO_2$ device, of which $VO_2$ patch width and electrode separation were 50 and $100{\mu}m$, respectively, was fabricated through a photolithographic method. A bias voltage range for stable bidirectional current switching was found by using the current-voltage property of the device measured in a current-controlled mode. The transient responses of bidirectionally switched currents were analyzed when the laser was modulated at a variety of pulse widths and repetition rates. A switching contrast was measured as ~3333, and rising and falling times were measured as ~39 and ~21ms, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.11
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• pp.28-34
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• 2015

By incorporating a 966nm near infrared laser, we demonstrated bidirectional current triggering of between 0 and 10mA in a two-terminal planar device based on a highly resistive vanadium dioxide ($VO_2$) thin film grown by a pulsed laser deposition method. A two-terminal planar device, which had an electrode separation of $100{\mu}m$ and a $50{\mu}m-wide$ $VO_2$ conducting layer, was fabricated through ion beam-assisted milling and photolithographic techniques. A bias voltage range for stable bidirectional current triggering was determined by investigating the current-voltage curves of the $VO_2-based$ device in a current-controlled mode. Bidirectional current triggering of up to 10mA was realized by directly illuminating the $VO_2$ film with a focused infrared laser beam, and the transient responses of triggered currents were analyzed when the laser was modulated at various pulse widths and repetition rates. A switching contrast between off- and on-state currents was evaluated as ~3571, and the rising and falling times were measured as ~40 and ~20ms, respectively.