• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1580-1584
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• 2010

In this paper, we made an analysis of the effective optical pulse stream generation. This is different from conventional approaches, which use fiber or waveguide delay line circuits. The optical pulse multiplication phenomenon occurs when the optical pulse's spectral width is greater than the transfer bandwidth of the coupler used. Therefore, the effective optical pulse stream generation can be controlled by using fiber couplers with different equivalent transfer bandwidths. The pulse separation spacing is controlled by number of cascaded coupler in optical loop mirror coupler scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.353-356
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• 2011

A Signal Receiving system to collect and analyze RF signals should be verified under simulated RF signal environment prior to verification on operation in fields and tested by using simulated RF signals in order to estimate its electrical performance. Generally, typical Signal Receiving system can measure, analyze frequency, pulse modulation, scan modulation, phase modulation on pulse, frequency modulation on pulse etc on RF signals. These RF signals should be generated from simulated RF sources in laboratory. Also the simultaneous RF signals should be simulated on laboratory. This paper describes the results of studying effective simulated RF signal source generation, the methods of the precise RF test signal generation in consideration of operational scenario.

• Nuclear Engineering and Technology
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• v.37 no.3
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• pp.279-286
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• 2005

A prototype of a relativistic proton generation system, based on laser-induced plasma interaction, has been designed and fabricated. The system is composed of three major parts: a fs TW laser; a target chamber, including targets and controls; and a diagnostic system for charged particles and lasers. An Offner-type pulse stretcher for chirped pulse amplification (CPA) and eight pass pre-amplifier are installed. The main amplifier will be integrated with a new pumping laser. The design values of the laser at the first stage are 1 TW in power and 50 fs in pulse duration. We expect to generate protons with their maximum energy of approximately 3 MeV and the flux of at least $10^6$ per pulse using a 10 $\mu$m Al target. A prototype target chamber with eight 8-inch flanges, including target mounts, has been designed and fabricated. For laser diagnostics, an adaptive optics based on the Shack-Hartmann type, beam monitoring, and alignment system are all under development. For a charged particle, CR-39 detectors, a Thomson parabola spectrometer, and Si charged-particle detectors will be used for the density profile and energy spectrum. In this paper, we present the preliminary design for laser-induced proton generation. We also present plans for future work, as well as theoretical simulations.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.62-69
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• 1996

Interpolator is a very important element in NC machines in that it controls tool path and speed. In this paper, studied were extensive interpolation characteristics of reference pulse method among various interpolation and pulse generation methods. Specifically, processing speed and path error of DDA, SPD and SFG methods were compared and analyzed against line, circle and elipse. As a result, in the point of processing speed, SPD method was found to be the best for line interpolation, SFG method for circle and ellipse, and DDA method was found to be the slowest for all paths. In the point of path error, DDA method was found to have the biggest error for all kinds of paths.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.331-341
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• 2018

This study proposes an integrated serial spring-damper mechanism as a dual pulse generation system. Compared to the traditional dual pulse generation system, which used multiple springs and a damper to generate a dual pulse critical for impact testing of naval equipments, currently used separated serial spring-damper mechanism is comprised of two components: an air spring, and a damper. The proposed mechanism combines the two components into one integrated system with a unique design that lets simply changing the volume and the pressure of the air tank, and the length of the annular pipe adjust the stiffness and damping constants for testing, eliminating the need to have multiple sets of air springs and dampers. Simulations using MatLab and Simulink were conducted to verify the feasibility of this design. The results show the potential of an integrated serial spring-damper mechanism as a more convenient and flexible mechanism for dual pulse generation system.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.5
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• pp.652-659
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• 2009

To analyze and verify the performance of a pulse radar without the real target data, there is a need to make the simulated signal which is similar to the received signal of the real target. In this paper, a method of the received signal generation for the pulse radar is proposed to solve the above need. The user-made scenarios are used to model the fast and small target and the clutter data based on the ground environment. These data are transformed into the electric signal using the proposed method. The efficiency of the proposed method is proved by comparing the signal of a field test with the simulated signal.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.9
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• pp.651-654
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• 1987

There are a number of small scale application fields of ozone, such as food conservation and/or storage in refrigerators, containers and storage rooms, deodorization in the production and living areas, protection against biohazards, bleaching of fabrics, etc. For these applications, miniaturization, ozone controllability and costdown of the ozonizer are the most essential points, whereas power efficiency is the most imporant factor in the case of a large scale ozonizer used in various industrial applications. It has been developed a novel sawtooth-to-cylinder type micro-ozonizer meeting above the three points by using a negative pulse corona discharge. As a result of the observations of pulse coronas affecting ozone generation, it is found that the maximum ozone concentration is generated at the pulse streamer coronas in both positive and negative case. The ozone concentration (20ppm/2l/min) generated by the negative pulse corona is about 2 times higher than that of the positive pulse corona, and could be controllable linearly by adjusting the dc input voltage of the [supply-inth ] cinventional small scale ozonizers. As a result, the present ozonizer is also very good to be used as a micro-ozonizer.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.361-362
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• 2009

High-order harmonics from gaseous atoms driven by an intense femtosecond laser pulse can form an attosecond pulse train. By selecting suitable harmonic generation conditions, the harmonic spectrum can be broad enough to form sub-hundred attoseconds. One serious limitation, however, comes from the inherent attosecond chirp originating from the harmonic generation process. We have proposed to compensate for the positive attosecond chirp by making use of negative group delay dispersion of a metallic x-ray filter or a gaseous medium. We generated 240-as pulses from neon and compressed them to 60 as after propagating through argon, close to the transform-limited duration of 47 as.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.157-158
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• 2008

High-order harmonics from gaseous atoms driven by an intense femtosecond laser pulse can form an attosecond pulse train. By selecting suitable harmonic generation conditions, the harmonic spectrum can be broad enough to form sub-hundred attoseconds. One serious limitation, however, comes from the inherent attosecond chirp originating from the harmonic generation process. We have proposed to compensate for the positive attosecond chirp by making use of negative group delay dispersion of a metallic x-ray filter or a noble gas. We generated 241-as pulses from neon and compressed them to 106 as after propagating through argon, close to the transform-limited duration of 98 as.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.946-949
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• 2004

We obtained ultra-short single pulse with an energy of 80 uJ from Distributed feedback Dye laser. Using three stages of amplifiers constructed by two stages of dye amplifiers and one bethune cell amplifier, we obtained high power pulse and second harmonic generation with BBO in ultraviolet region.