• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.127-132
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• 2006

Bacillus sp. strain K-l, which produces a strong fibrinolytic enzyme, was isolated from chongkukjang, a traditional Korean fermented soybean paste. The fibrinolytic enzyme was purified from chongkukjang base by using ammonium sulfate fractionation and chromatographic techniques. Purified enzyme, CK K-1 was demonstrated to be homogeneous by SDS-PAGE and isoelectric focusing electrophoresis, and has molecular mass of a 12.4 kDa and a pI of 8.0. The optimal reaction pH value and temperature were 8.0 and $40^{\circ}C$, respectively. Phenyl-methyl-sulfonyl-fluoride (PMSF; serine protease inhibitor), ethylene-diamine-tetra-acetic acid (EDTA; metallo protease inhibitor), copper ion, ferric ion and lead ion inhibited the enzyme activity. These results indicated that the fibrinolytic enzyme is a metallo-serine protease and different from nattokinase and chongkukjangkinase.

• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.587-594
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• 2016

Various surface treatments and thin film coating processes on the surface of injection die steel have been developed to extend the life. Most of previous studies were mainly focused on investigating the wear and static bonding behavior of thin films. In this study complex surface treatments of DLC coating combined with ion nitriding were applied to increase fatigue life and wear resistance. Ion nitriding, DLC coating, and DLC coating following nitriding on the surface of Fe-3.0Ni-0.7Cr-1.4Mn-X steel were investigated to uncover the beneficial effect which is applicable to injection die. The effect of various surface treatments and coating conditions on high cycle fatigue resistance was studied. Surface morphology change during fatigue tests were observed with AFM. Fatigue life of the die steel increased by 10 to 1,000 times at the various level of stress amplitudes in the condition of DLC coating following the ion nitriding for 3 hrs comparing with the only DLC coated condition.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.323-331
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• 2015

Zirconium alloys are widely used in nuclear reactors as structural materials. During the operation, they are exposed to fast neutrons. Ion irradiation is used to simulate the damage introduced by neutron irradiation. In this article, we briefly review the neutron irradiation damage of zirconium alloys, then summarize the effect of ion irradiation on microstructural evolution, mechanical and corrosion properties, and their relationships. The microstructure components consist of dislocation loops, second phase precipitates, and gas bubbles. The microstructure parameters are also included such as domain size and microstrain determined by X-ray diffraction and the S-parameter determined by positron annihilation. Understanding the relationships of microstructure and properties is necessary for developing new advanced materials with higher irradiation tolerance.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4644-4651
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• 2022

Due to its short half-life, thoron gas has been assumed to have negligible health hazards on humans compared to radon. But, one of the decay products with a long half-life can make it to be transported to a long distance and to cause a severe internal dose through respiration. Since most commercial radon detectors can not discriminate thoron signals from radon signals, it is very common to overestimate radon doses which in turn result in biased estimation of lung cancer risk in epidemiological studies. Though some methods had been suggested to measure thoron and radon separately, they could not be used for real-time measurement because of CR-39 or LR-115. In this study, an effective method was suggested to measure radon and thoron separately from the free air. It was observed that the activity of thoron decreases exponentially due to delay time caused by a long pipe between two chambers. Therefore from two ion chambers apart in time, it was demonstrated that thoron and radon could be measured separately and simultaneously. We also developed a collimated alpha source and with this source and an SBD, we could convert the ion chamber reading to count rate in cps.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.223-230
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• 2006

In this paper the method for repair LCC evaluation of reinforced concrete structures deteriorated by chloride attack was constructed. Also, the FEM analysis for chloride ion penetration into concrete was conducted to evaluate the repair LCC which was decided by the number of repair times including early stages of construction and repair construction during the service life of structures. As a result, the number of repair times is obtained from the comparing the concentration of the chloride ion in a rebar position, and the critical chloride ion concentration of rebar corrosion through the FEM analysis considering the kind of repair materials and methods. Also, the repair LCC could be calculated by the number of repair times during the service life of structures.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.252-256
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• 2001

The rapid development of communication equipment and information processing technology has led to a constant improvement in cordless communication. Lithium ion batteries used in cellular phones and laptop computers, in particular, have been in the forefront of the above revolution. These batteries use high value added raw materials and have a high and stable energy output and are increasingly coming into common use. The development of the material for the negative terminal has led to an improvement in the quality and efficiency of the batteries, whereas a reduction in the cost of the battery by researching new materials for the positive anode has become a research theme by itself. These long life batteries, it is being increasingly realized, can have value added to them by recycling. Research is increasingly being done on recycling the aluminum case and the load casing for the negative diode. This paper aims to introduce the current situation of recycling of lithium ion batteries. 1. Introduction 2. Various types of batteries and the situation of their recycling and the facts regarding recycling. 3. Example of cobalt recycling from waste Lithium ion secondary cell. 3-1) Flow Chart of Lithium ion battery recycling 3-2) Materials that make a lithium ion secondary cell. 3-3) Coarse grinding of Lithium ion secondary cell, and stabilization of current discharge 3-4) Burning 3-5) Grinding 3-6) Magnetic Separation 3-7) Dry sieving 3-8) Dry Classifying 3-9) Content Ratio of recycled cobalt parts 3-10) Summary of the Line used for the recovery of Cobalt from waste Lithium ion battery. 4. Conclusion.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.594-597
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• 2006

Chloride ion penetration and carbonation are the most important factors in the durability problems of reinforced concrete structures. Most of the existing studies on those subjects are focused on the no-crack concrete, though the existence of crack may strongly affect the chloride ion penetration and carbonation. To evaluate the influence of crack on the chloride ion penetration and carbonation and to assess the service life of reinforced concrete more accurately, finite volume analyses (FVA) were performed based on the FV mesh containing the ideal crack whose width is uniform along the depth. Analytical results show that the influence of crack width and depth is much more pronounced for the chloride ion penetration than for the carbonation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.219-220
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• 2010

The purpose of this study is to evaluate chloride ion attack durability of concrete structure having experienced the high temperature fire. Mechanical properties and anti chloride ion diffusivity of concrete specimens were measured which have experienced of 2 hours heating at $200{^{\circ}C},\;400{^{\circ}C},\;600{^{\circ}C},\;800{^{\circ}C}$. The coupling FE model of thermal transfer and chloride ion diffusion was built to predict the life expectancy of RC structure using the property values by a series of experiment.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.155-159
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• 2004

We synthesized ion exchange resin that can remove $NO_3\;^-$ selectively rather than $SO_4\;^{2-}$. Ion exchange property of the synthesized ion exchange resin occurred like the following process, $NO_3\;^-$ > $SO_4\;^{2-}$, the efficiency of functional group to remove $NO_3\;^-$ occurred in the process of $NPr_3$ > $NBu_3$ > $NEt_3$ > $NMe_3$ > $NPe_3$ > $N(EtOH)_3$, and the efficiency of functional group to remove $SO_4\;^{2-}$ occurred in the process of $NMe_3$ > $NEt_3$ > $NPr_3$ > $NBu_3$ > $NPe_3$.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.635-644
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• 2018

Lithium ion batteries have been broadly used in various applications to our daily life such as portable electronics, electric vehicles and grid-scale energy storage devices. Significant efforts have recently been made on developing electrode materials for lithium ion batteries that meet commercial needs of the high energy density, light weight and low cost. In this review, we summarize the principles and recent research advances in cathode and anode materials for lithium ion batteries, and particularly emphasize electrode material designs and advanced characterization techniques.