• The Korean Journal of Food And Nutrition
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• v.32 no.2
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• pp.148-154
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• 2019

The aim of this study was to select compounds for the standardization of fermented Kalopanax pictus Nakai (KP-F), to develop the analysis method using HPLC-PDA and to perform method validation. KP-F is a fermented powder developed to improve the original physiological activities and create a new functionality. Eleutheroside E, Acanthoside B, and Syringaresinol were selected as the standard compounds and developed our own method for simultaneous analysis. The analyte was isolated using C18 column with a gradient elution of 0.05 M phosphoric acid in water and methanol as the mobile phase at a flow rate of 1 mL/min and detected at 210 nm. As a result, all standard compounds showed good linearity with an $R^2$ (coefficient of correlation) of 1.000 and for the limit of detection range of $0.710{\sim}0.831{\mu}g/mL$, and the limit of quantification as $2.150{\sim}2.520{\mu}g/mL$. The precision was RSD (%) of less than 4.80%, while the accuracy was 4.70%>RSD (%) for the range 102.44~110.48%. In conclusion, the developed analysis method is suitable for the detection of Eleutheroside E, Acanthoside B, and Syringaresinol in KP-F.

• Resources Recycling
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• v.27 no.6
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• pp.30-37
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• 2018

A series of experiment was conducted to evaluate basic performances of low-pH, anti-washing grouts incorporating gypsum which applied for reinforcing underwater cavities in limestone- grounds. Various types of mix proportions were designed and the fluidity, strength and environmental impact of these mixtures were evaluated. The flowability was evaluated under two conditions, i.e., flows without and with pressing, respectively. Strength was measured for the hardened mixtures fabricated under conditions of air and water injections. The environmental impacts including the pH of the suspension and the suspended solids concentration for the mixtures were evaluated. The low pH of fresh mixture suspension, below than 10, was achieved by incorporation of gypsum. The mix proportions of cement-quartz powder-gypsum binders and chemical agents resulted in mortar natural flow 7-10 cm and uniaxial compressive strength 4 MPa were derived.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.56-62
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• 2021

In this study, we created a DBD plasma device and a MnO2 catalyst mesh filter for evaluating ozone reduction of devices via the catalyst method. The DBD plasma device was manufactured by applying Ag paste to soda lime glass via the screen-printing method. The MnO2 catalyst mesh filter was manufactured by mixing MnO2 powder with binder with a 10% difference in concentration from 10% to 50% and then applying it using the dip-coating method. Finally, we sintered a MnO2 catalyst mesh filter in an electric furnace. We evaluated the characteristics of ozone generation according to the Ar gas flow of DBD plasma devices, the opening ratio, and ozone reduction performance of the MnO2 catalyst filters. Ozone reduction performance was approximately 20.4% at MnO2 10 wt%, 37.8% at MnO2 30 wt% and 50% at MnO2 50 wt%.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.506-513
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• 2022

In this paper, as part of a study for carbon neutrality, the quality properties of quaternary component high-fluidity concrete, which significantly replaced up to 80 % of the cement usage by using three industrial by-products, were evaluated. As a result of the evaluation, even if a large amount of industrial by-products were replaced by more than 80 % of the amount of cement used, it was possible to obtain quality that satisfies the target performance in all concrete mix. In the case of flow properties, mechanical properties, and durability, compared to the existing standard concrete mix, the performance tends to decrease, but it is judged that the performance above the required performance level can be satisfied. When considered comprehensively, the quaternary component High-Fluidity Concrete with a large mixing amount of fine powder of blast furnace slag showed relatively good performance.

• Journal of Ginseng Research
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• v.46 no.6
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• pp.809-818
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• 2022

Background: The non-saponin fraction (NSF) of Korean Red Ginseng is a powder in which saponin is eliminated from red ginseng concentrate by fractionation. In this study, we examined the effect of NSF on age-associated sarcopenia in old mice. Methods: NSF (50 or 200 mg/kg/day) was administered orally daily to young (3-6-month-old) and old (20-24-month-old) C57BL/6 J mice for 6 weeks. Body weight and grip strength were assessed once a week during the oral administration period. The gastrocnemius and quadriceps muscle were excised, and the muscle fiber size was compared through hematoxylin and eosin staining. In addition, the effect of NSF on sarcopenia and inflammation/oxidative stress-related factors in hindlimb muscles was investigated by western blotting. Flow cytometry analysis was conducted to investigate the effect of NSF on immune homeostasis. Blood samples were collected by cardiac puncture, and the serum levels of insulin-like growth factor 1, pro-inflammatory cytokines, and glutathione were evaluated. Results: NSF significantly alleviated muscle strength, mass, and also fiber size in old mice. Age-associated impairment of immune homeostasis was recovered by NSF through retaining CD11b⁺F4/80⁺ macrophages and regulating inflammatory biomarkers. NSF also decreased the age-induced expression of oxidative stress factors. Taken together, NSF showed the effect of improving sarcopenia by inhibiting low-grade chronic inflammatory/oxidative stress factors. Conclusion: NSF exhibited anti-sarcopenia effects by regulating chronic inflammation and oxidative stress in old mice. Thus, we suggest that NSF is a promising restorative agent that can be used to improve sarcopenia in the elderly as well as maintain immune homeostasis.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.10-14
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• 2008

Differently from BSCCO tapes which are fabricated by powder-in-tube method, the coated conductors are made by the evaporation of YBCO on metal substrate. Due to this structural merit, although the coated conductors are generally used for large current transportation, they are expected to be favorable to the purpose of the fault current limitation as well. In this study, using YBCO coated conductor having copper stabilizer formed by plating technique(produced by Superpower Co.), we investigated the over-current characteristics of the coated conductor. The coated conductors had 85 A $I_c$ and 90 K $T_c$. The resistance of the conductor was 0.93 $m{\Omega}/cm$ at 300 K and 0.17 $m{\Omega}/cm$ at the temperature right above $T_c$. To the coated conductors, we applied the voltages of the range from 150 $V_{rms}$ to 230 $V_{rms}$ and measured the V-I curves using four probe method. From the results, we could analyze the electric behavior of the coated conductor in flux flow state. As the current exceed $I_c$, the currents were distributed into the superconductor and metal stabilizer. The amounts of the currents shared through both current paths were calculated under the assumption that the ,Joule heating was perfectly eliminated by $LN_2$ surrounding the conductor. Finally, the condition for the stable current flowing state which does not affect the conductor was established from the analysis on the over-current characteristics.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.25-31
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• 2023

In this study, the basic properties of CO₂ immobilized desulfurized gypsum (CFBG) and the possibility of being used as a stimulus for slag cement were reviewed, and performance evaluation was conducted through a concrete mixing test. The main components of CFBG were CaO and SO₃, and CaO and SO₃ increased as the drying temperature increased. The moisture content of undried CFBG was 15.7 %, the drying temperature was 1.7 % and the drying temperature was 0.03 % at 105 ℃. Mortar using CFBG tended to have a lower flow value as the drying temperature increased, and the compressive strength was equivalent to that of the FGB use mixture. As a result of the concrete experiment using CFBG SC, both slump and air volume satisfied the target range after 60 minutes, and the compressive strength tended to increase overall compared to the ternary binder mixture.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.1-7
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• 2023

This study has utilized self-assembled monolayers technology to improve electrical property of graphene-oxide, which has been seperated graphine powder through a chemical exfoliation. Aluminum sulfate (Al₂(SO₄)₃) was applied on graphene-oxide as a reactant, and the fundamental research was carried out to apply on the self-sensing of cement-based construction structures. Electric resistance measurement result has shown that cement-composites with GO and Al-GO can be used as a conductor, electric resistance of GO and Al-GO contained composites improved by 10.2% and 15.9% respectively when compared to the standard cement-composite. Microstructure analyzation shown the formation of Al(OH)₃ gel when Al-GO was added, which is speculated to result the smooth flow of current by improving the density of cement-composite. This implies that graphene-oxide has a possibility to be utilized as smart building materials and construction structure itself rather than just a structure.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.3
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• pp.121-127
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• 2023

When high carbon steel is heated in an appropriate austenizing temperature range and subjected to austempering, the size and shape of lamellar structure can be controlled. The high carbon steel sheet having the pearlite structure has excellent elastic characteristics because it has strong restoring force when properly rolled, and is applied in a process known as patenting-process using lead bath. In the case of isothermal treatment using lead-medium, it is possible to quickly reach a uniform temperature due to high heat transfer characteristics, but it is difficult to replace it with process technology that requires treatment to remove harmfulness lead. In this study, we intend to develop fluidization technology using garnet powder to replace the lead medium. After heating the high-carbon steel, the cooling rate was changed by compressed air to the vicinity of the nose of the continuous cooling curve, and then maintained for 90 s and then exposed to room temperature. The microstructure of the treated specimens were analyzed and compared with the existing products treated with lead bath. The higher the flow rate of compressed air, the faster the cooling rate to the pearlite transformation temperature, so lamellar spacing decreases and the hardness tends to increase.

• Composites Research
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• v.20 no.4
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• pp.9-17
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• 2007

Powder metallurgy has been employed for the development of SiC particle reinforced aluminum metal matrix composites by means of hot isotropic pressing and vacuum hot pressing. A material model based on micro-mechanical approach then has been presented for the processes. Densification occurs by the inelastic flow of matrix materials during the consolidation, and consequently it depends on many process conditions such as applied pressure, temperature and volume fraction of reinforcement. The model is implemented into finite element software so that the process simulation can be performed enabling the predicted relative density to be compared with experimental data. In order to determine the performance of finished products, further tensile test has been conducted using the developed specimens. The effect of internal void of the materials on mechanical properties therefore can be investigated.