• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1373_1374
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• 2009

The PLS-II, the major upgrade program of the PLS (Pohang Light Source, a 2.5-GeV 3rd generation light source), is planned at the Pohang Accelerator Laboratory. Given the glaring lack of normative data regarding the PLS-II the major upgrade, this study can be seen as the first in a needed stream of research investigating selection by dual gun and dc electron gun. Usable electron gun can think method to use dual electron gun and method to prove energy by existing electron gun in energy increase. This article is concerned with the formal classification of used of pre-injector electron gun type of the DC and pulse. Design concept wishes to show contents that design for pulse type of power supply and DC type of electron gun.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1527-1536
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• 1993

A new transmitter circuit for remote controllers is designed to provide flexibility and expandibility in function. The circuit employs a microcode approach to accept various code format, length and pulse widths through programming, and the precessing logics is eliminated to reduce its size. The circuit was Implemented using FPGA(Field Programmable Gate Array) and it was found to operate successfully).

• Advances in Energy Research
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• v.2 no.1
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• pp.47-59
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• 2014

Back-to-back STATCOM configuration is an extension of STATCOM in which the reactive power at two-sides and the real power flow through the DC link can be controlled concurrently and independently. This flexible operation brings many advantages to the micro-grids, distributed generation based systems, and deregulated power systems. In this paper, the dynamic control characteristics of the back-to-back STATCOM is investigated by simulating the detailed converter-level model of the converters in PSCAD. Various case studies in a single-machine test system are studied to present that the real power control feature of the BtB-STATCOM, even with a simple controller design, can enhance the transient stability of the machine under different fault scenarios.

• Vacuum Magazine
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• v.2 no.1
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• pp.17-20
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• 2015

In this article, a historical and scientific review on the development of an ultrafast electron microscope is supplied, and the challenges in further improvement of time resolution under sub-picosecond or even sub-femtosecond scale is reviewed. By combining conventional scanning electron microscope and femtosecond laser technique, an ultrafast electron microscope was invented. To overcome its temporal resolution limit which originates from chromatic aberration and Coulomb repulsion between individual electrons, a generation of electron pulse via strong-field photoemission has been investigated thoroughly. Recent studies reveal that the field enhancement and field accumulation associated with the near-field formation at sharply etched metal nanoprobe enabled such field emission by ordinary femtosecond laser irradiation. Moreover, a considerable acceleration reaching 20 eV with near-infrared laser and up to 300 eV acceleration with mid-infrared laser was observed, and the possibility to control the amount of acceleration by varying the incident laser pulse intensity and wavelength. Such findings are noteworthy because of the possibility of realizing a sub-femtosecond, few nanometer imaging of nanostructured sample.in silicon as thermoelectric materials.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.611-615
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• 2014

We report high-speed pulse train generation from a relatively low-speed 10-GHz mode-locked laser by means of line-by-line spectral coding. To increase the pulse repetition rate multiplication (RRM) factor, we combine coding schemes for both spectral intensity and phase by placing a simple mask at the coder focal plane. The resulting RRM factor, determined by multiplying the RRM factors of the individual coding schemes, rises as high as 16. To verify the generated pulses, the optical spectra and autocorrelation traces are examined.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1556-1558
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• 1994

An air/quartz dielectric double barrier pulse discharge has been investigated to develop a novel si lent type ozone generator. It is found that there are very active pulsed coronas occurred in the airgap which are very useful for ozone generation. And, the corona onset voltage of the airgap of the air/quartz double barrier was enfluenced greatly by the airgap of the air/quartz dielectric double barrier, and depended greatly upon the airgap ranged of $0.0{\sim}3.0mm$ and by the quartz tube thickness ranged of $1.75{\sim}2.25mm$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.415-424
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• 2016

This paper describes a high data rate proximity transmitter design for high resolution smartphone-mirrored display applications. A 2 Gb/s transmitter is designed with a low transmission power of -70 dBm/MHz and a wide bandwidth of nearly 3 GHz. A digital pre-correction method is employed in the transmitter to mitigate the inter-symbol interference problem. A carrier-based digital pulse shaping and a reconfigurable digital envelope generation methods are employed for robust operation by utilizing 20 phases from a 2 GHz phase-locked loop. A 6.5-9.5 GHz transmitter implemented in 65 nm CMOS achieves the maximum data rate of 2 Gb/s, consuming only 7.6 mW from a 1 V supply.

• Structural Engineering and Mechanics
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• v.42 no.3
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• pp.363-381
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• 2012

This study is aimed at providing an efficient analytical model to obtain pressure- impulse diagram of one-way reinforced concrete slabs subjected to different shapes of air blast loading using single degree of freedom method (SDOF). A tri-linear elastic perfectly plastic SDOF model has been used to obtain the pressure-impulse diagram to correlate the blast pressure and the corresponding concrete flexural damage. In order to capture the response history for the slab, a new approximately SDOF method based on the conventional SDOF method is proposed and validated using published test data. The influences of pulse loading shape on the pressure-impulse diagram are studied. Based on the results, a pressure-impulse diagram generation method using SDOF and an analytical equation for the pressure-impulse diagram is proposed to different damage levels and different blast loading shapes.

• Journal of IKEEE
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• v.14 no.2
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• pp.9-15
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• 2010

In this study, we have been proposed the new type of a transcranial magnetic stimulation adopted a variable voltage capacitor with Cockcroft-Walton circuit and constant-frequency current resonant half-bridge inverter. This a transcranial magnetic stimulation has some merits compared with the conventional one. First, it doesn't require the high voltage transformer. And second, it has less switching losses, compact size and capability in adjusting the transcranial magnetic stimulation output energy precisely. In this paper, we have performed the output characteristics of a transcranial magnetic stimulation system which is well known as magnetic stimulation. The tested results are described as a function of pulse repetition rate and switching numbers of the half-bridge inverter.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.213-220
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• 2003

By the localization of electro-chemical dissolution region, we succeeded in a few micrometer size hole drilling on stainless steel with the radial machining gap of about 1 ${\mu}{\textrm}{m}$. Tens of nanosecond duration voltage pulses were applied between WC micro-shaft and stainless steel in the 0.1 M $H_2SO_4$ solution. Pt balance electrode was used to drill the high aspect ratio micro-hole without generation of Cr oxide layer on the machined surface. The effects of applied voltage, pulse duration, and pulse period on localization distance were investigated according to machining time. We suggested the taper reduction technique especially brought up on blind-hole machining. High quality micro-holes with 8 ${\mu}m$ diameter with 20 ${\mu}m$ depth and 12 ${\mu}m$ diameter with 100 ${\mu}m$ depth were drilled on 304 stainless steel foil. The various hole shapes were also produced including stepped holes and taper free holes.