• Proceedings of the Korean Vacuum Society Conference
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• 1996.06a
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• pp.67-67
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• 1996

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.84-92
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• 2014

The purpose of study is to analyze mechanism with early high portland cement and hardening accelerator. As the result, it was concluded that hardening accelerator makes accelerates appearance of $Ca(OH)_2$ through experiment using TG-DTA when it hydrates with cement. On the result of compressive strength, as increasing the amount of hardening accelerator used, early compressive strength was improved. Also, as a result of hydration heat, hardening accelerator accelerates hydration of $C_3S$ that is cement's component. On the result of XRD's analyzation, hydration product for each age could be check and it was shown that as increasing the amount of hardening accelerator used, peak point of hydration product was recorded high. As the result of SEM, appearance of C-S-H was shown as the amount of $Ca(OH)_2$'s appearance and each age according to additive contents of hardening accelerator. Therefore hardening accelerator used on this study is effective on getting early compressive strength.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1656-1658
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• 2003

고전압 대전류 시스템에 사용하는 스위치의 기본 요구조건은 저가, 긴 수명, 적은 지터와 대용량 그리고 seal-off 형태로 쉽게 설치하여 운전하는 것이다. 본 논문은 고전압 대전류용 Seal-off TVS (Triggered Vacuum Switch)를 개발하는 것을 목적으로 하고있다. 제작한 TVS는 양전극과 음전극이 교대로 고정된 간격으로 각각 3개의 전극으로 배열되어 있으며 전극은 사다리꼴 모양으로 되어있고 트리거 시스템과 개스를 흡수하는 게터가 내부에 설치되어 있다. 제작한 스위치 내부는 약 $10^{-7}$ torr의 진공상태를 유지하고 있으며 세라믹 챔버를 사용하여 Seal-off 상태로 설계, 제작하였다. TVS의 에너지 최고 전달량은 74 C 이며 30 kV, 100 kA, $1{\sim}2$ ms의 스위치를 제작하여 시험을 하였다. 스위치 시험 장치는 200 ${\mu}F$, 22 kV 6개를 병렬로 연결한 커패시터 뱅크와 160 ${\mu}H$의 인덕터와 0.2 ${\Omega}$의 저항을 이용하여 시험 장치를 구성하였다. 본 논문은 제작한 스위치의 전기적인 특성 시험한 결과에 대하여 논하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.355-366
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• 2022

This paper proposes a microcode-based neural network accelerator controller for artificial intelligence accelerators that can be reconstructed using a programmable architecture and provide the advantages of low-power and ultra-small chip size. In order for the target accelerator to support various neural network models, the neural network model can be converted into microcode through microcode compiler and mounted on accelerator to control the operators of the accelerator such as datapath and memory access. While the proposed controller and accelerator can run various CNN models, in this paper, we tested them using the YOLOv2-Tiny CNN model. Using a system clock of 200 MHz, the Controller and accelerator achieved an inference time of 137.9 ms/image for VOC 2012 dataset to detect object, 99.5ms/image for mask detection dataset to detect wearing mask. When implementing an accelerator equipped with the proposed controller as a silicon chip, the gate count is 618,388, which corresponds to 65.5% reduction in chip area compared with an accelerator employing a CPU-based controller (RISC-V).

• Nuclear Engineering and Technology
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• v.37 no.5
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• pp.447-456
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• 2005

Laser driven accelerators promise to provide an alternative to conventional accelerator technology. They rely on the excitation of large amplitude density waves in a plasma by the photon pressure of an intense laser. The density oscillations in which electrons and ions are separated, result in extremely large longitudinal electric fields that can be several orders of magnitude larger than those that are used in today's radio-frequency accelerators. Whereas this principle had been demonstrated experimentally for nearly two decades, it was not until 2004 that the production of high quality electron beams around 100 MeV was demonstrated. Analysis, aided by particle-in-cell simulations, as well as experiments with various plasma lengths and densities, indicate that tailoring the length of the accelerator, together with loading of the accelerating structure with beam, are the keys to production of mono-energetic electron beams. Increasing the energy towards a GeV and beyond will require reducing the plasma density and design criteria are discussed for an optimized accelerator module. The current progress and future directions are summarized through comparison with conventional accelerators, highlighting the unique short and long term prospects for intense radiation sources and high energy accelerators based on laser-drivenplasma accelerators.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.92-92
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• 2018

Silene seulensis Nakai was used as traditional medicines in Korea, we collected plant from demilitarized zone (DMZ). S. seulensis was extracted with 30, 50, and 70% ethanol and partitioned successively with n-hexane, EtOAc, dichloromethane and BuOH. These extracts (30, 50 and 70% ethanol) were evaluated the cytotoxicity on B16F10 and Hacat cell lines. The LC-MS/MS data of each fractions (n-hexane, EtOAc, dichloromethane, and BuOH) were compared with MS library, combined with ultraviolet/visual (UV/Vis) and MS data for faster determine structure by database search results. This led to the identification of four compounds (1-4) from S. seulensis. These compounds was isolated first time from S. seulensis. Their chemical structures are elucidated by combinations of NMR and mass spectrometry techniques.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.523-528
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• 2013

The beam position monitor (BPM) is an essential component for the PEFP 100-MeV linac's commissioning. A prototype stripline-type linac BPM was designedfor this purpose. The electrode aperture is 20 mm in diameter, and the electrode is 25 mm long, so it can be installed between Drift Tube Linac (DTL)101 and DTL102, which is the shortest distance. One end of the electrode is connected to the Sub Miniature Type A (SMA) feed through for signal measurement, and the other end is terminated as a short. The signal amplitude of the fundamental component was calculated and compared with that of the second harmonic component. The designed BPM was fabricated and a low-power RF test was conducted. In this paper, the design, fabrication and low power test of the BPM for the PEFP linac are presented.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.102-102
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• 2019

This study developed a HPLC analysis method for the determination of avicularin (AL) and quercitrin (QT) in Astilbe chinensis by HPLC. HPLC was performed on a Capcell Pak C18 MGII column ($4.6{\times}250mm$, $5{\mu}m$) with a gradient elution of 0.05% (v/v) trifluoroacetic acid (TFA) and acetonitrile at a flow rate of 1.0 mL/min at $30^{\circ}C$ and a UV detection wavelength of 254 nm. The analytical method was validated for its specificity, precision, accuracy, and linearity. The limits of detection and quantitation were AL 0.09 and 0.28 mg/mL, QT 0.03 and 0.09 mg/mL respectively. Calibration curves showed good linearity (AL r2 > 0.99990 and QT r2 > 0.99994), and the precision of analysis was satisfied (less than AL 0.59%, QT 0.63%). Recoveries of quantified compounds ranged from AL 100.57 to 102.08%, QT 99.94 to 100.64%. These results indicate that the developed HPLC method was applied successfully to the detection of AL and QT in A. chinensis.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.100-100
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• 2019

This study attempted to establish a High Performance Liquid Chromatography (HPLC) analysis method for the determination of (-)-epicatechin gallate as a part of the quality control for the development of functional cosmetic materials from Penthorum chinense Pursh extracts. HPLC was performed on a Unison US-C18 column ($4.6{\times}250mm$, $5{\mu}m$) with a gradient elution of 0.05% (v/v) trifluoroacetic acid (TFA) and methyl alcohol at a flow rate of 1.0 mL/min at $30^{\circ}C$. The analyte was detected at 280 nm. The HPLC method was performed in accordance with the International Conference on Harmonization (ICH) guideline (version 4, 2005) of analytical procedures with respect to specificity, precision, accuracy, and linearity. The limits of detection and quantitation were 0.11 and 0.33 mg/mL, respectively. Calibration curves showed good linearity (r2 > 0.9999), and the precision of analysis was satisfied (less than 0.6%). Recoveries of quantified compounds ranged from 99.51 to 101.92%. This result indicates that the established HPLC method is very useful for the determination of marker compound in P. chinense Pursh extracts.

• Journal of Venture Innovation
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• v.5 no.3
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• pp.1-17
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• 2022

Entrepreneurs recognize that their passion was an important factor in driving successful entrepreneurship. However, they were often unaware of the impact that third-party passions related to startups have on them. Therefore, in this study, it was verified whether the accelerator incubation program had an effective effect on portfolios. At this time, I tried to do an empirical analysis focusing on how the third-party accelerator entrepreneur passion affects the entrepreneurial performance of portfolios. To this end, a survey was conducted on representatives of portfolios across the country who completed the accelerator incubation program, and empirical testing was conducted based on 330 valid ones. As a result of empirical analysis, it was confirmed that mentoring and networking among accelerator incubation programs had a positive (+) effect on entrepreneurial performance of portfolios. On the other hand, education and seed investment in the accelerator program did not significantly affect the entrepreneurial performance of portfolios. On the other hand, it was tested that accelerator entrepreneur passion significantly moderated both the incubation program elements (education, mentoring, network, seed investment) and the entrepreneurial performance of portfolios. The results of this study are meaningful in that they reveal that the passion of accelerator entrepreneurs is an important lynchpin of incubation programs and the key to success in startups. In addition, this study suggests that it is important for startups to go one step further from seed investment and properly identify the accelerator entrepreneur and his passion, the key man of accelerators.