• Analytical Science and Technology
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• v.14 no.3
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• pp.203-211
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• 2001

In this paper it was described on the intereference effect of uranium to analyze Cs in $UO_2$ by Electron Probe Micro Analysis(EPMA) and the beam stability of Cs $L_{\alpha}$ X-ray intensity for some Cs compounds. According to the experimental results, the CsI showed the highest $L_{\alpha}$ X-ray intensity among the tested Cs compounds at the experimental condition; 15~30 kV of accelerating voltage and PET, LiF crystal. When 100 nA of beam current was applied to Cs compounds, Cs $L_{\alpha}$ X-ray intensity was continuously decreased with increasing time. The decreasing rate of Cs $L_{\alpha}$ X-ray intensity was directly proportional to the applied beam current and accelerating voltage but inversely proportional to the applied beam size. It was found that uranium interference can be prevented by using Cs $L_{\alpha}$ X-ray wavelength of Lif crytal for Cs analysis in $UO_2$ by EPMA.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.182-189
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• 2009

The noise from the sunroof can be divided into the low frequency buffeting noise and the high frequency turbulence noise generated when a car runs at the high driving speed. The wind deflector suppresses the buffeting noise generation by accelerating the vortex shedding from the front edge of sunroof opening, and guides the flow direction so that air can pass smoothly over the sunroof opening. To reduce the buffeting noise and the high frequency noise, it is very important to locate a deflector in a proper position depending on the driving speed and the sunroof opening width. The deflector's sectional shape also plays an important role in efficiently reducing the buffeting and high frequency noise. In this paper, we determined the optimum deflector's sectional shape and examined the flow characteristics behind a sunroof deflector through CFD analysis with changing the deflector height, the driving speed and the sunroof opening width. It is found that the deflector needs to be located in the higher location to control the buffeting noise by shedding the higher frequency vortices to accelerating vortices from the sunroof front edge. The deflector may act as a new noise source at the high driving speed, then it is desirable to put the deflector at the proper height to reduce the flow fluctuations and the noise generation. We also made a road test to verify CFD analysis results in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.2993-2999
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• 2015

Steel companies are applying Ni-B or Ni-Co alloy plating to protect the surface of Continuous casting mold, and they are using saccharin polish which causes crack on plating layer due to sulfur in saccharin. It is considered that the Ni-S compound causes the cracking and additional tensile stresses. The Ni-Mn-B ternary alloy plating was developed for suppression of crack by forming Mn-S compound before Ni-S compound is formed, but there were no domestic or international standard on the Ni-Mn-B alloy plating. Therefore, reliability evaluation standard was established to evaluate the newly developed Ni-Mn-B plating. To develop accelerating life testing method, FMEA(Failure Mode & Effective analysis) was used to analyze the cause of the main failure in plating. The Ni-Mn-B reliability standard included accelerating life test method, and it was categorized by the fundamental performance test, environment test, and accelerated life test, and was designed to guarantee 1 000 hours of B10 life with 80 % reliable level.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.387-394
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• 1983

The factor, which was capable of accelerating the yeast cell wall lysis of the zymolyase(${\beta}-1$, 3-glucanase), was purified to a homogeneous state from the protease fraction of the crude zymolyase by Sephadex G-75 gel filtration and preparative polyacrylamide gel disc electrophoresis. The molecular weight of the purified factor was estimated to be 40,500 by SDS-polylacrylamide gel disc electrophoresis and it's iso-electric point was pH 9.6. The factor was found to be a basic protease consisted of single polypeptide chain with 395 amino acid residues and it showed the $E_{280,cm}^{1%}$ of 11.9 and the molecular extinction coefficient of $4.83{\times}10^4$, respectively.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.42.2-43
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• 2018

When galaxy clusters interact, the intergalactic gas collides, forming shocks that are characterized by a low sonic Mach number (~3) but a comparatively high Alfvenic Mach number (~30). Such shocks behave differently from the more common astrophysical shocks, which tend to have higher sonic Mach numbers. We wish to determine whether these shocks, despite their low sonic Mach number, are capable of accelerating particles and thereby contributing to the cosmic ray spectrum. Using the PIC-MHD method, which separates the gas into a thermal and a non-thermal component to increase computational efficiency, and relying on existing PIC simulations to determine the rate at which non-thermal particles are injected in the shock, we investigate the evolution of galaxy cluster shocks and their ability to accelerate particles. Depending on the chosen injection fraction of non-thermal particles into the shock, we find that even low-Mach shocks are capable of accelerating particles. However, the interaction between supra-thermal particles and the local magnetic field triggers instabilities and turbulence in the magnetic field. This causes the shock to weaken, which in turn reduces the effectiveness of the supra-thermal particle injection. We investigate how this influences the shock evolution by reducing the particle injection rate and energy and find that a reduction of the particle injection fraction at this stage causes an immediate reduction of both upstream and downstream instabilities. This inhibits particle acceleration. Over time, as the instabilities fade, the shock surface straightens, allowing the shock to recover. Eventually, we would expect this to increase the efficiency of the particle injection and acceleration to previous levels, starting the same series of events in an ongoing cycle of increasing and decreasing particle acceleration.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.179-189
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• 2019

The market participation and development of major manufacturers of next-generation green vehicles is accelerating in recent years. The results of this study are as follows: Consumer type (personal value pursuit type, price value pursuit type) was significant difference between consumer. The results of this study were as follows: First, there was no significant difference in the characteristics of consumers (gender, age, monthly average income) and purchase intention according to age, gender and monthly average income, Image has a positive (+) impact on eco-friendly vehicles. This suggests that the development and market participation of next - generation green vehicles is accelerating and consumers 'interest is increasing, and the characteristics of environment - friendly vehicles and the government' s policy support are important factors.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.5-12
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• 2011

Recently, NDS(Natural and Durable Stabilizer)method and other similar methods are composed of inorganic accelerating agent and the ultra-super fine cement have been studied as the ground improvement material in Korea. However, in the existing research, the chemical changing process of NDS in the strength development mechanism with the elapsed curing time and the principles of strength development did not give an explanation. For the popularization of the inorganic grout material, it determined that the mechanism verifying of the curing process had to be clearly preceded. Therefore, unconfined compression test, SEM and XRD analysis were performed by the elapsed curing time and were analyzed. In addition, the same trial for SGR method, that is the representative example of the water glass grout material, was selected as comparative target in order to distinguish properties of NDS more clearly. The result of experiment, the strength development mechanism of NDS could be investigated through the close correlation of the unconfined compression strength - SEM - XRD analysis, and excellence of a performance was confirmed.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.73-78
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• 2022

Due to COVID-19, the digital transformation centered on unmanned and non-face-to-face is accelerating. Like a digital civilization, it is changing into a digital age, but for those who cannot use digital, the inconveniences in daily life are falling to the level of digital illiteracy. There is a social gap between digital users and non-users, and digital non-users are separated from society. For the digital socialization of the digitally underprivileged, the transition to the digital world is accelerating, and the ability to use digital in everyday life is becoming more important. As the transition to the digital world accelerates, individual social and economic differences are occurring. These problems are hindering the sustainable growth of society. In this study, in order to receive digital education conveniently, we intend to design an education model with excellent accessibility as an education that can be received by all citizens. It is intended to propose a digital education model that can be used universally and solve the inconvenience of life through digital comprehensive competency education that can be received step by step and can be easily received.

• Composites Research
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• v.22 no.6
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• pp.39-44
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• 2009

The effect of exposure times on the aging characteristics of carbon fiber/epoxy composite ring specimen was evaluated using an accelerating aging tester. Combined exposure conditions, such as temperature, moisture, and ultraviolet, were applied up to 3000 hours. Tensile properties and flexural properties including the effect of curvature were evaluated on the specimens subject to various exposure times through a material testing system. Their aging surfaces were observed through a scanning electron microscope. According to the results, tensile modulus was little affected by the exposure times. However, tensile strength, at the early stage of the exposure times, increased due to physical aging and curing reaction, but tensile strength slightly decreased due to degradation as the exposure times increased. The flexural modulus and flexural strength increased at the early stage of the exposure times, but slightly decreased as the exposure times increased. Aging surfaces of the specimens examined using the scanning electron microscope revealed a different morphology in various exposure times and provided useful information for identifying the degradation in mechanical properties of the composite subject to various exposure times.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.131-138
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• 2024

The effect of magnetite particles on the anaerobic digestion (AD) of furfural wastewater was investigated using sequential anaerobic batch tests. The batch tests with four 500 mL anaerobic bioreactors were performed under two conditions: FC treatment for AD of furfural without magnetite particles, and FM treatment for AD of furfural with magnetite particles. The FC bioreactors showed a decreasing methane production rate (MPR) across the sequential batches, with a final batch MPR of 11.3 ± 0.4 mL CH₄/L/d, indicating the need for a methanogenesis enhancer to achieve high-rate AD of furfural. Conversely, FM bioreactors exhibited significantly higher MPR, exceeding FC values by 4-196%, with a final batch MPR of 33.5 ± 0.1 mL CH₄/L/d, which was about three times higher than FC. Additionally, FM bioreactors had faster degradation rates of furfural, valeric acid, and acetic acid compared to FC, with values exceeding those in PC by 3.0, 1.14, and 2.8 times, respectively. These results demonstrate that magnetite particles can enhance the AD of furfural not only by accelerating methanogenesis but also by accelerating the anaerobic degradation of furfural and its intermediates, such as volatile fatty acids. This study provides valuable insights for developing high-rate AD systems for furfural wastewater treatment.