• Journal of Powder Materials
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• v.28 no.6
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• pp.470-477
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• 2021

Energy storage systems should address issues such as power fluctuations and rapid charge-discharge; to meet this requirement, CoFe₂O₄ (CFO) spinel nanoparticles with a suitable electrical conductivity and various redox states are synthesized and used as electrode materials for supercapacitors. In particular, CFO electrodes combined with carbon nanofibers (CNFs) can provide long-term cycling stability by fabricating binder-free three-dimensional electrodes. In this study, CFO-decorated CNFs are prepared by electrospinning and a low-cost hydrothermal method. The effects of heat treatment, such as the activation of CNFs (ACNFs) and calcination of CFO-decorated CNFs (C-CFO/ACNFs), are investigated. The C-CFO/ACNF electrode exhibits a high specific capacitance of 142.9 F/g at a scan rate of 5 mV/s and superior rate capability of 77.6% capacitance retention at a high scan rate of 500 mV/s. This electrode also achieves the lowest charge transfer resistance of 0.0063 Ω and excellent cycling stability (93.5% retention after 5,000 cycles) because of the improved ion conductivity by pathway formation and structural stability. The results of our work are expected to open a new route for manufacturing hybrid capacitor electrodes containing the C-CFO/ACNF electrode that can be easily prepared with a low-cost and simple process with enhanced electrochemical performance.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.643-659
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• 2022

Geologic sequestration technologies such as CCS (carbon capture and storage), EGS (enhanced geothermal systems), and EOR (enhanced oil recovery) have been widely implemented in recent years, prompting evaluation of the mechanical stability of storage sites. As fluid injection can stimulate mechanical instability in storage layers by perturbing the stress state and pore pressure, poroelastic models considering various injection scenarios are required. In this study, we calculate the pore pressure, stress distribution, and vertical displacement along a surface using commercial finite element software (COMSOL); fault slips are subsequently simulated using PyLith, an open-source finite element software. The displacement fields, are obtained from PyLith is transferred back to COMSOL to determine changes in coseismic stresses and surface displacements. Our sequential use of COMSOL-PyLith-COMSOL for poroelastic modeling of fluid-injection and induced-earthquakes reveals large variations of pore pressure, vertical displacement, and Coulomb failure stress change during injection periods. On the other hand, the residual stress diffuses into the remote field after injection stops. This flow pattern suggests the necessity of numerical modeling and long-term monitoring, even after injection has stopped. We found that the time at which the Coulomb failure stress reaches the critical point greatly varies with the hydraulic and poroelastic properties (e.g., permeability and Biot-Willis coefficient) of the fault and injection layer. We suggest that an understanding of the detailed physical properties of the surrounding layer is important in selecting the injection site. Our numerical results showing the surface displacement and deviatoric stress distribution with different amounts of fault slip highlight the need to test more variable fault slip scenarios.

• Food Science and Preservation
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• v.15 no.3
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• pp.377-384
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• 2008

The gamma irradiation process was performed to prolong a shelf-life of peaches and the effects of a gamma irradiation on the nutritional, physiochemical and sensory characteristics of peaches were evaluated during a post-irradiation storage at $4^{\circ}C$ and $25^{\circ}C$. Nutritional, physiochemical and sensory characteristics of peaches were stable at 1 kGy of an irradiation, a recommended dose for fruits and vegetables by CODEX, and the viable cell counts of contaminated microorganisms were reduced by 2 decimal reduction, at this dose. After a 1-week storage at ambient condition, the microbiological quality of the 1 kGy irradiated peach was stable, while all the non-irradiated peaches were deteriorated Furthermore, cold storage enhanced the shelf-life of the gamma irradiated peach and the nutritional and physiochemical characteristics of the peaches were comparatively stable up to 6 weeks. Right after gamma irradiation, the sensory evaluation results were not different in any of the samples, and the sensory quality of the irradiated peaches was adequate for a 4-week storage at $4^{\circ}C$. Our results suggested that gamma irradiation at 1 kGy can be used to enhance the shelf-life of peach without a significant loss in the quality attributes, especially upon cold storage after radiation treatment.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.376-380
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• 2016

A composite electrode made of iron oxide nanoparticles/multi-wall carbon nanotube (iNPs/M) delivers high specific capacity and cycle durability. At a rate of $200mAg^{-1}$, the electrode shows a high discharge capacity of ${\sim}664mAhg^{-1}$ after 100 cycles, which is ~ 70% of the theoretical capacity of $Fe_3O_4$. Carbon black, carbon nanotube, and graphene as anode materials have been explored to improve the electrical conductivity and cycle stability in Li ion batteries. Herein, iron oxide nanoparticles on acid treated MWCNTs as a conductive platform are combined to enhance the drawbacks of $Fe_3O_4$ such as low electrical conductivity and volume expansion during the alloying/dealloying process. Enhanced performance was achieved due to a synergistic effect between electrically 3D networks of conductive MWCNTs and the high Li ion storage ability of $Fe_3O_4$ nanoparticles (iNPs).

• YAKHAK HOEJI
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• v.39 no.5
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• pp.487-494
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• 1995

Solid lipid microspheres (SLMs) were prepared using various lipids and solidifying agents, in order to enhance the gastrointestinal absorption of Cyclosporine A (Cs A) which is a practically water-insoluble drug with low systemic bioavailability. Egg lecithin and HCO-60 (polyoxyethylated 60 mol, hydrogenated castor oil) were used as lipids. Stearic acid and stearyl alcohol were used as solidifying agents. Emulsion concentrates containing Cs A were prepared by mixing the melted lipid and solidifying agent with water, employing bile salts as a cosurfactant. SLMs were obtained by dispersing the warm emulsion concentrate in cold distilled water under mechanical stirring, followed by freeze drying. Physical characteristics of each SLM were investigated by particle size analysis, optical microscopy and scanning electron microscopy. Mean particle size of SLMs was in the range of 30 to 40.mu.m. The SLMs were in good appearance with spherical shape before freeze drying, but were deformed partially after freeze drying. Drug loading efficiencies of SLMs were observed as high as 80 to 90% in average. The systemic bioavailability of Cs A from different SLM formula was investigated in rats following oral administration. Cs A in whole blood was extracted and assayed by HPLC. SLMs revealed the higher bioavailabilities than the standard formula based on the marketed product. SLMs might have several advantages over standard formula for enhanced gastrointestinal absorption, controlled release properties, high loading capacity of the water-insoluble drug, and feasibility of solid dosage forms with better stability in storage.

• BMB Reports
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• v.55 no.1
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• pp.39-47
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• 2022

Adoptive cell transfer (ACT), a form of cell-based immunotherapy that eliminates cancer by restoring and strengthening the body's immune system, has revolutionized cancer treatment. ACT entails intravenous transfer of either tumor-resident or peripheral blood-modified immune cells into cancer patients to mediate anti-tumor response. Although these immune cells control and eradicate cancer via enhanced cytotoxicity against specific tumor antigens, several side effects have been frequently reported in clinical trials. Recently, exosomes, potential cell-free therapeutics, have emerged as an alternative to cell-based immunotherapies, due to their higher stability under same storage condition, lower risk of GvHD and CRS, and higher resistance to immunosuppressive tumor microenvironment. Exosomes, which are nano-sized lipid vesicles, are secreted by living cells, including immune cells. Exosomes contain proteins, lipids, and nucleic acids, and the functional role of each exosome is determined by the specific cargo derived from parental cells. Exosomes derived from cytotoxic effectors including T cells and NK cells exert anti-tumor effects via proteins such as granzyme B and FasL. In this mini-review, we describe the current understanding of the ACT and immune cell-derived exosomes and discuss the limitations of ACT and the opportunities for immune cell-derived exosomes as immune therapies.

• Korean Journal of Materials Research
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• v.33 no.4
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• pp.159-163
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• 2023

Zinc-ion Batteries (ZIBs) are currently considered to be effective energy storage devices for wearable electronics because of their low cost and high safety. Indeed, ZIBs show high power density and safety compared with conventional lithium ion batteries (LIBs) and exhibit high energy density in comparison with supercapacitors (SCs). However, in spite of their advantages, further current collector development is needed to enhance the electrochemical performance of ZIBs. To design the optimized current collector for high performance ZIBs, a high quality graphene film is suggested here, with improved electrical conductivity by controlling the defects in the graphene film. The graphene film showed improved electrical conductivity and good electron transfer between the current collector and active material, which led to a high specific capacity of 346.3 mAh g^-1 at a current density of 100 mA g^-1, a high-rate performance with 116.3 mAh g^-1 at a current density of 2,000 mA g^-1, and good cycling stability (68.0 % after 100 cycles at a current density of 1,000 mA g^-1). The improved electrochemical performance is firmly because of the defects-controlled graphene film, leading to improved electrical conductivity and thus more efficient electron transfer between the current collector and active material.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.408-418
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• 2023

In this study, we synthesized and characterized garnet-type Li_7-xAl_xLa₃Zr_2-(5/4)yNbyO₁₂ (LALZN) solid electrolytes for all-solid-state battery applications. Our novel approach focused on enhancing ionic conductivity, which is crucial for battery efficiency. A systematic examination found that co-doping with Al and Nb significantly improved this conductivity. Al³⁺ and Nb⁵⁺ ions were incorporated at Li⁺ and Zr⁴⁺ sites, respectively. This doping resulted in LALZN electrolytes with optimized properties, most notably enhanced ionic conductivity. An optimized mixture with 0.25 mol each of Al and Nb dopants achieved a peak conductivity of 1.32 × 10^-4 S cm^-1. We fabricated symmetric cells using these electrolytes and observed excellent charge-discharge profiles and remarkable cycling longevity, demonstrating the potential for long-term application in battery systems. The garnet-type LALZN solid electrolytes, with their high ionic conductivity and stability, show great potential for enhancing the performance of all-solid-state batteries. This study not only advances the understanding of effective doping strategies but also underscores the practical applicability of the LALZN system in modern energy storage solutions.

• Journal of the Korean institute of surface engineering
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• v.57 no.2
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• pp.57-70
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• 2024

Nickel-cobalt-manganese (NCM) lithium-ion batteries(LIBs) are increasingly prominent in the energy storage system due to their high energy density and cost-effectiveness. However, they face significant challenges, such as rapid capacity fading and structural instability during high-voltage operation cycles. Addressing these issues, numerous researchers have studied the enhancement of electrochemical performance through the coating of NCM cathode materials with substances like metal oxides, lithium composites, and polymers. Coating these cathode materials serves several critical functions: it acts as a protection barrier against electrolyte decomposition, mitigates the dissolution of transition metals, enhances the structural integrity of the electrode, and can even improve the ionic conductivity of the cathode. Ultimately, these improvements lead to better cycle stability, increased efficiency, and enhanced overall battery life, which are crucial for the advancement of NCM-based lithium-ion batteries in high-demand applications. So, this paper will review various cathode coating materials and examine the roles each plays in improving battery performance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.181-186
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• 1992

For the effective utilizing of refined filefish viscera oil, it was added to fish meat paste based products as a dietary supplement of polyunsaturated fatty acids. The storage stability and physicochemical properties of the product(kamaboko) was tested. Lipid oxidation of kamaboko could be retarded and texture expressed as jelly strength could be enhanced by adding of emulsion curd prepared from water, refined filefish viscera oil and soybean protein and sodium erythorbate during the storage at 5$^{\circ}C$. These results suggested the possibility that the refined filefish viscera oil containing highly polyunsaturated fatty acid, especially EPA and DHA could be used as a food ingredient for dietary supply of the lipids.