• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.261-261
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• 2012

This paper presents the understandings carried out for the installation of the hydrogen reservoir of the multi-gap pseudospark switch under developing for the accelerator applications. As a cold cold cathode switch, the pseudospark switch could replace the thyratron switch which has hot cathode and being used well currently in the high power field such as laser and accelerator applications. Especially in the klystron modulator, the key component is a switch which mostly defines the jitter and the instability of the modulator system. To get the less jitter and the instability, we need to find proper range of the pressure for the gas discharge inside gas switch. This could be achieved by the understanding of the characteristic of the nonevaporable getter (NEG) which is used as a hydrogen reservoir for the switch. Therefore we verified the characteristics of the NEG (St 172, Saes) and its installation in the switch. Finally we controlled the getter to find best pressure point for the pseudospark switch.

• 한국진공학회지
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• 제7권s1호
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• pp.140-148
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• 1998

We prepared $C_3N_4$ films by rf plasma enhanced chemical vapor deposition(PCVD) and alternating $C_3N_4$/TiN composite films by dc magnetron sputtering. X-ray diffraction (XRD) and transmission electron diffraction (TED) revealed that the structure of the films is amorphous or polycrystalline, depending on deposition conditions and heat treatment. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy confirmed the presence of $sp_3\; and sp _2$ hybridized C atoms bonded with N atoms in the tetrahedral and hexagonal configurations, respectively. Graphite-free $C_3N_4$ films were obtained by PCVD under optimal conditions. To prepare well crystallized $C_3N_4$ films by magnetron sputtering, we introduced negatively biased gratings in the sputtering system. CN films deposited at grating voltages (Vg) lower than 400V are amorphous. Crystallites of cubic and $\beta$-$C_3N_4$ were formed at increased voltages.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4648-4663
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• 2020

This paper proposes the Lempel-Ziv 4(LZ4) compression accelerator optimized for scale-out servers in data centers. In order to reduce CPU loads caused by compression, we propose an accelerator solution and implement the accelerator on an Field Programmable Gate Array(FPGA) as heterogeneous computing. The LZ4 compression hardware accelerator is a fully pipelined architecture and applies 16 dictionaries to enhance the parallelism for high throughput compressor. Our hardware accelerator is based on the 20-stage pipeline and dictionary architecture, highly customized to LZ4 compression algorithm and parallel hardware implementation. Proposing dictionary architecture allows achieving high throughput by comparing input sequences in multiple dictionaries simultaneously compared to a single dictionary. The experimental results provide the high throughput with intensively optimized in the FPGA. Additionally, we compare our implementation to CPU implementation results of LZ4 to provide insights on FPGA-based data centers. The proposed accelerator achieves the compression throughput of 639MB/s with fine parallelism to be deployed into scale-out servers. This approach enables the low power Intel Atom processor to realize the Hadoop storage along with the compression accelerator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1732-1734
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• 2001

The purpose of this experiment was to develope Triggered Vacuum Switch(TVS) and to improve understanding of the high current vacuum arc phenomena in the TVS. The TVS has an array of rods of alternate polarity in which a fixed gap spacing is maintained between the rods. The cross section of each rod has trapezoidal shape. Breakdown of the TVS produced high current vacuum arc plasma. A spectroscopic measurement was performed over 20 kA peak current in the center of electrodes, in the vicinity of cathode, and outside electrodes. The electrode material tested was Fe. Measured Fe spectrum range was from 200 nm to 900 nm. Measurement result showed that over 90 percent of the charge states were FeII and the others were FeI and FeIII. The electron temperature was determined from the relative line intensity ratio methode of FeII system by assuming the local thermal equilibrium(LTE). The electron temperature at the center of electrodes was measured as 1.5 eV at 26 kA peak current. The electron temperature varied with its peak current. Intensity of spectrums is the highest in the vicinity of the cathode. Further we will also present study result of the diode phenomena in the TVS.

• 한국터널지하공간학회 논문집
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• 제4권1호
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• pp.45-55
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• 2002

1980년 초 서울지하철 건설공사를 계기로 국내의 터널공사에 NATM(New Austrian Tunnelling Method)공법이 적용되고 있다. 하지만, 주지보재의 하나인 숏크리트 기술은 NATM공법이 국내에 들어온 초기의 기술력을 아직 답습하고 있는 상태로 다량의 리바운드가 발생하고, 노즐맨의 경험이나 기량등에 의존하는 경우가 많아 비용절감 및 시공능률 향상을 위한 개선이 절실히 요구되고 있는 실정이다. 본 논문에서는 숏크리트 품질확보에 중요한 위치를 차지하고 있는 급결제(Accelerator)를 주변수로 강섬유보강 숏크리트(SFRS)에 대한 모형시험을 실시하여 고품질 숏크리트에의 적용 가능성을 검토하였다. 모형시험(압축강도, 휨강도, 휨인성)결과, Alkali-free 액상급결제를 사용한 숏크리트를 통해 고강도 발현을 위한 고가의 혼화재를 사용하지 않고서도 고품질의 고강도 숏크리트 개발 가능성을 확인할 수 있었으며, Single-Shell Lining 터널 등 Permanent Shotcrete Lining이라는 새로운 개념의 터널 지보시스템 구축을 위한 요소기술로 그 적용이 확대될 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.143-144
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• 2015

In this research it was attempted to analyze the general engineering properties of low cement mortar according to the type of setting accelerator and substitution rate, when 1% substitution rate for setting accelerator was used a high rate of compressive strength manifestation was shown and that the WS-10 type setting accelerator was appropriate. For the rate of change of length, when 3% substitution rate for setting accelerator was used, it was shown that due to initial expansion the shrinkage compensation was not significant, and when taking into consideration strength and shrinkage, 1% of WS-10 was shown to be appropriate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1322-1323
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• 2008

기존의 펨토 초 레이저를 이용하여 발생시킨 테라 헤르츠 광원의 한계를 극복하기 위하여 대용량의 가속기를 이용한 테라 헤르츠 광원의 발생에 관한 연구가 활발히 진행되고 있다. 포항방사광 가속기연구소에서도 펨토 초 테라 헤르츠 빔을 이용한 분광학적인 방법을 사용하여 단백질 접힘과 DNA-단백질 간 상호작용, 화학적, 생물학적인 반응 동력학 등에 관한 연구와 영상 기술개발 등을 할 계획을 가지고 펨토초 테라 헤르츠 빔 라인을 건설 중에 있다. 펨토 초-테라 헤르츠 빔 라인의 마이크로웨이브를 가속하는 장치에 사용되는 전원장치의 설계와 제작 및 시험과정을 외국기술에 의존하지 않고 순수 국내기술로 실현하였다. 본 논문에서는 펄스 모듈레이터의 설계와 실험결과를 보이고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2149-2152
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• 2005

가속기 연구소에서 500kV 고전압 다중채널 다중갭(MGMC) 스위치를 개발하였다. 이 다중 채널 다중 갭 스위치는 개스를 채우는 방식으로 자발 방전전압을 증가 시킬 수 있는 10단의 갭으로 구성이 되어 있다. 멀티갭 스위치의 구조는 스위치의 자체 인덕턴스를 증가시키는 결과를 가져온다. 따라서 이러한 문제점을 해결하기 위하여 다중채널을 사용하여 인덕턴스를 줄이는 스위치로 구조를 설계하였다. 제작된 스위치는 500kV의 Marx generator를 사용하여 시험을 하였다. 본 논문에서는 개발된 스위치 선계 및 스위치의 특성에 대하여 알아보고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 전기설비
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• pp.31-32
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• 2006

Pohang accelerator Laboratory is from 1994 analyzed electric power amount used for about 10 years. It is one of equipment that consume electric power of greate electric power to single test equipment. Accelerator Laboratory institute investigates the consumption rate of energy that is spent to each building could divide by linear accelerator and save ring and analyzed about the equipment utilization rate and average electric power. Countermeasure that this treatise can forecast power loss of electric power by equipment through analysis of electric power amount used and heighten the utilization rate of equipment wishes to do comparative analysis.

• 한국IT서비스학회지
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• 제18권3호
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• pp.129-141
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• 2019

Currently, there is a wave of second startup companies in Korea as well as within the global market, and the role of accelerators have become highly important at the center of changes. In the early 2000s, Y-Combinator has made Airbnb and Dropbox grow into a global company, and its start-up support model has begun to gain worldwide attention, and further became the beginning of the "accelerator" industry. The accelerator industry has been expanding rapidly throughout the United States, Britain and Israel, as well as China and Southeast Asia in recent years. As of the end of 2018, more than 130 accelerators have been operating in Korea, starting with Primer in 2010, and the scope of its activities has been expanding into specialty fields such as Pintech, bio industry, and Block chain, as well as Game. The purpose of this study is to study the role of the accelerator through the phenomenon of these accelerators and their step-by-step support services.