• Journal of the Korean Society for Heat Treatment
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• v.7 no.4
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• pp.307-317
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• 1994

The surf ace microstructure modification by $N^+$ ion implantation into 7050Al alloy and its low cycle fatigue behavior were investigated. Ion implantation method is to physically implant accelerated ions to the surface of a substrate. High dose of nitrogen($5{\times}10^{17}ions/cm^2$) were implanted into 7050Al alloy using current density of accellerating voltage of 100KeV. The implanted layers were characterized by Electron Probe-Micro Analysis(EPMA), Auger Elecron Spectroscopy(AES), X-Ray Diffraction(XRD), X-Ray Photoelectron Spectroscopy(XPS), and Transmission Electron Microscopy(TEM). The experimental results were compared with computer simulation data. It was shown that AlN was formed to 4500 ${\AA}$ deep. The low cycle fatigue life of the $N^4$ion modified material was prolonged by about three times the unimplanted one. The improved low cycle fatigue life was attributed to the formation of AlN and the damaged region on the surface by $N^+$ ion implantation.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.578-583
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• 2005

Cell-free culture broth of marine halophilic bacterium, Kordia algicida was shown to possess specific algicidal ability against red tide organism, Cochlodinium polykrikides. Physiochemical characteristics of algicidal material originated in the bacterial culture broth were analyzed that its molecular weight was estimated to a 3,000 dalton and it was stable in heat and pH treatment. The algicidal fraction against C. polykrikoides obtained from gel permeable chromatography contained high concentration of ammonium ion as analyzed by ICP/Mass spectrum. C. polykrikoides by the fraction was quickly lysed within 1 min. It was shown that the effective concentration for algicide against C. polykrikoides was over 1mM of ammonium chloride. On the other hand, other metal ions presented in the algicidal fraction showed no algicidal effect against C. polykrikoides. In additon, ammonium ion exhibited species-specific killing spectrum for two species of red tide organisms, C. polykrikoides and Gymnodinium sanguieum. Therefore, further researches on the killing mechanism against C. polykrikoides exerted by ammonium ion, and subsequent development of replaceable algicidal materials will perform to provide useful tools for the control of red tide.

• Transactions on Electrical and Electronic Materials
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• v.9 no.5
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• pp.206-208
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• 2008

Implantation of metals and ceramics with ions of nitrogen and other species has improved surface properties such as friction, wear and corrosion in numerous industrial applications. In recent years, PCB drills tend to be more minimized increasingly as the electronics components have been more highly accumulated and minimized. Therefore nitrogen ion implantation was performed onto PCB drill (0.15 & 0.3 mm in diameter), in order to investigate mechanical properties of WC-Co cermets surface through Nano-indentation tests. PCB drill was implanted at energy of 70 keV, 90 keV, 120 keV and with the dose range of $1{\times}10^{17}$ and $5{\times}10^{17}\;ions/cm^{2}$. After ion implantation, WC-Co PCB drill bits was tested in actual operating situation to apply cutting tools industry and is concluded that the life time of nitrogen ion implanted PCB drills is one and a half times longer than the unimplanted.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.163-171
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• 2019

Common features of neurodegenerative diseases (NDDs) include progressive dysfunctions and neuronal injuries leading to deterioration in normal brain functions. At present, ginseng is one of the most frequently used natural products. Its use has a long history as a cure for various diseases because its extracts and active compounds exhibit several pharmacological properties against several disorders. However, the pathophysiology of NDDs is not fully clear, but researchers have found that various ion channels and specific signaling pathways might have contributed to the disease pathogenesis. Apart from the different pharmacological potentials, ginseng and its active compounds modulate various ion channels and specific molecular signaling pathways related to the nervous system. Here, we discuss the signal modulating potential of ginseng and its active compounds mainly focusing on those relevant to NDDs.

• Journal of Electrochemical Science and Technology
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• v.12 no.4
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• pp.415-423
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• 2021

For a battery module where single cells are connected in series, the single cells should each have a similar state of charge (SOC) to prevent them from being exposed to an overcharge or over-discharge during charge-discharge cycling. To detect the existence of unbalanced SOC cells in a battery module, we propose a simple measurement method using a single-frequency response of electrochemical impedance spectroscopy (EIS). For a commercially available graphite/nickel-cobalt-aluminum-oxide lithium-ion cell, the cell impedance increases significantly below SOC20%, while the impedance in the medium SOC region (SOC20%-SOC80%) remains low with only minor changes. This impedance behavior is mostly due to the elementary processes of cathode reactions in the cell. Among the impedance values (Z, Z', Z"), the imaginary component of Z" regarding cathode reactions changes heavily as a function of SOC, in particular, when the EIS measurement is performed around 0.1 Hz. Thanks to the significant difference in the time constant of cathode reactions between ≤SOC10% and ≥SOC20%, a single-frequency EIS measurement enlarges the difference in impedance between balanced and unbalanced cells in the module and facilitates an ~80% improvement in the detection signal compared to results with conventional EIS measurements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.753-759
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• 2006

To predict service life of concrete structures exposed to chloride attack, surface chloride concentration, diffusion coefficient of chloride ion, and chloride corrosion threshold value in concrete, are used as important factors. Of these, as the diffusion coefficient of chloride ion for concrete is strongly influenced by concrete quality and environmental conditions of structures and may significantly change the service life of structures, it is considered as the most important factor for service life prediction. The qualitative factors affecting the penetration and diffusion of chloride ion into concrete are water-cement (W/C) ratio, age, curing conditions, chloride ion concentration of given environment, wet and dry conditions, etc. In this paper the influence of W/C ratio and curing conditions on the diffusion characteristics of chloride ion in concrete was investigated through the chloride ion diffusion test. In the test, the voltages passing through the diffusion cell were measured by accelerated test method using potential difference, and then with the consideration of IR drop ratio the diffusion coefficient of chloride ion for concrete with different W/C ratios were estimated by Andrade's model. Furthermore, under different curing conditions formulas for the estimation of the diffusion coefficient of chloride ion have been proposed by the regression analysis considering the effect of W/C ratio and age.

• Analytical Science and Technology
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• v.11 no.2
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• pp.135-138
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• 1998

The change of amino acids was analysed with cotyledons and roots of young spring radish by the treatment of $Cd^{2+}$ ion and $Cd^{2+}$ ion plus PA. The concentration of Asp was decreased by the treatment of $Cd^{2+}$ ion, but Ala, Phe, Val, Ile, Typ, Lys and Arg was increased in the cotyledons. The concentration of Lys and Arg was decreased by the treatment of $Cd^{2+}$ ion plus PA at the same time. The concentration of basic amino acids, His, Lys and Arg was increased by the treatment of $Cd^{2+}$ ion, and decreased by the treatment of $Cd^{2+}$ ion and $Cd^{2+}$ ion plus PA in the roots. Only the concentration of Pro was increased by the treatment of $Cd^{2+}$ ion plus PA. This results showed that Pro was induced against stress of PA, and assumed that the change of other amino acids concentration may be relation to the metabolism against stress.

• Food Science and Preservation
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• v.12 no.6
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• pp.534-539
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• 2005

Effects of grapefruit seed extract and Ag ion solution on the keeping quality and shelf life of mungbean sprouts were investigated in terms of weight loss, gas composition, hardness, color, ascorbic acid content, and viable cell counts during storage. Packages with $30\;{\mu}m$ polypropylene(PP) film was applied for mungbean sprouts dipped in Ag ion solution, 50 ppm and 100 ppm GFSE, 50 ppm and 100 ppm GFSE in Ag ion solution and stored $5^{\circ}C$. Totally weight loss exceeded $1\%$ and no visible signs of shrivelling of mungbean sprouts were observed. GFSE in Ag ion solution treatment, resulting in mungbean sprouts of better visual quality, weight loss, color, ascorbic acid as compared to the control without dipping. A shelf life of 6 days was achieved with 100 ppm GFSE in Ag ion solution treatment.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1151-1156
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• 2023

In this paper, we propose a deep learning model that utilizes charge/discharge data from initial lithium-ion batteries to predict the remaining useful life of lithium-ion batteries. We build the DMP using the PNP model. To demonstrate the performance of DMP, we organize DML using the LSTM model and compare the remaining useful life prediction performance of lithium-ion batteries between DMP and DML. We utilize the RMSE and RMSPE error measurement methods to evaluate the performance of DMP and DML models using test data. The results reveal that the RMSE difference between DMP and DML is 144.62 [Cycle], and the RMSPE difference is 3.37 [%]. These results indicate that the DMP model has a lower error rate than DML. Based on the results of our analysis, we have showcased the superior performance of DMP over DML. This demonstrates that in the field of lithium-ion batteries, the PNP model outperforms the LSTM model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.133-138
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• 2024

Lithium-ion batteries are used in many fields due to their high energy density, fast charging conditions, and long cycle life. However, overcharging, over-discharging, physical damage, and use of lithium-ion batteries at high temperatures can reduce battery life and cause damage to people due to fire or explosion due to damage to the protection circuit. In order to reduce the risk of these batteries and improve battery performance, the characteristics of the charging and discharging process must be analyzed and understood. Therefore, in this paper, we analyze the charging and discharging characteristics of lithium-ion batteries using a battery charger and discharger and simulator to reduce the risk of loss of life due to overcharge and overdischarge, as well as casualties from fire and explosion due to damage to the protection circuit.