• 대한의생명과학회지
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• 제29권4호
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• pp.242-248
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• 2023

Platelets are activated at the sites of vascular injury by a number of molecules, including adenosine diphosphate, collagen and thrombin. The full platelet aggregation is absolutely essential for the normal hemostasis. Glycyrrhiza glabra is a well-known medicinal herb that grows in various parts of the world and is known to have various effects such as antioxidant, anti-inflammatory, anti-atherogenic, anti-osteoporotic and skin-whitening. However, the platelet inhibitory effect of Glycyrrhiza glabra extract (GGE) has not been identified. In this study, we investigated if GGE inhibited platelet aggregation. We observed that GGE inhibited collagen-induced platelet aggregation, Ca²⁺ mobilization, and thromboxane A2 generation. In addition, GGE suppressed phosphorylation of phosphatidylinositol-3 kinase (PI3K), Akt and elevated phosphorylation of inositol 1,4,5-trisphosphate receptor (IP3R), vasodilator stimulated phosphoprotein (VASP). Taken together, GGE showed strong antiplatelet effects and may be used to block platelet-mediated cardiovascular diseases.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3571-3580
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• 2023

The application of the induction bending process to pipe systems in various industrial fields is increasing. Recently, efforts have also been made to apply this bending process to nuclear power plants because it can innovatively reduce welded parts of the curved pipes, such as elbows. However, there have been no cases of the application of induction bending to the piping of nuclear power plants. In this study, the applicability of the P91 induction bending piping for the sodium-cooled fast reactor PGSFR was validated through high temperature low cycle fatigue tests and creep tests using P91 induction bending pipe specimens. The tests confirmed that the materials sufficiently satisfied the fatigue life and the creep rupture life requirements for P91 steel at 550 ℃ in the ASME B&PV Code, Sec. III, Div. 5. The results show that the effects of heating and bending by the induction bending process on the material properties were not significant and the induction bending process could be applicable to piping system of PGSFR well.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4477-4490
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• 2023

Fuel locking mechanisms (FLMs) are essential in upward-flow research reactors to prevent accidental fuel separation from the core during reactor operation. This study presents a novel design concept for a remotely controlled plate-type nuclear fuel locking mechanism. By employing electromagnetic field analysis, we optimized the design of the electromagnet for fuel unlocking, allowing the FLM to adapt to various research reactor core designs, minimizing installation space, and reducing maintenance efforts. Computational flow analysis quantified the drag acting on the fuel assembly caused by coolant upflow. Subsequently, we performed finite element analysis and evaluated the structural integrity of the FLM based on the ASME boiler and pressure vessel (B&PV) code, considering design loads such as dead weight and flow drag. Our findings confirm that the new FLM design provides sufficient margins to withstand the specified loads. We fabricated a prototype comprising the driving part, a simplified moving part, and a dummy fuel assembly. Through basic operational tests on the assembled components, we verified that the manufactured products meet the performance requirements. This remote-controlled micro locking mechanism holds promise in enhancing the safety and efficiency of plate-type nuclear fuel operation in upflow research reactors.

• 한국물환경학회지
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• 제26권2호
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• pp.303-310
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• 2010

Recently distinguished AOP means technology resolving organic compounds in water to harmless compounds such as $CO_2$ and $H_2O$ by creating OH radical ($OH{\cdot}$) with more powerful oxidation than general oxidants. It has merits which the 2nd pollution is not caused since it uses solar energy, sludge doesn't take place, it can be applied to high-density waste water and it oxidizes non-biodegradable organic compounds more easily. The purpose of the study was to examine about removable characteristics of phenol which was a non-biodegradable organic matter with UV/$O_3$/Catalyst processes which is one out of AOP and to present applicability of photocatalyst and the optimum conditions of treatment. The study regarded initial phenol concentration, initial pH, photocatalyst amount and flow as its conditions. As the results, the test had the highest removable efficiency (92%) when initial phenol concentration was 100 mg/L, initial pH 7, photocatalyst amount 6L and flow 1.5 mg/min. The removable efficiency was increased as much as initial phenol concentration was increased, when initial pH was 7 (neutrality), photocatalyst amount was increased and flow was increased. It was checked that the optimum HRT was 12 hours. Therefore, phenol is enough removable with UV/$O_3$/Catalyst process and its prospect in the future is expected.

• 에너지공학
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• 제20권2호
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• pp.84-89
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• 2011

본 연구는 하수슬러지에 알칼리처리와 초음파처리를 적용하여 최적의 가용화 조건을 도출하고자 각각의 단일처리, 병합처리로 가용화율을 확인하였다. 단일처리 중 알칼리처리는 4종의 알칼리시약을 각각 적용하여 전처리한 결과, NaOH를 이용한 방법이 27.6%로 가장 높은 가용화율을 확인할 수 있었으며, 주입농도가 높아지더라도 가용화에 미치는 영향에는 한계가 있음을 확인하였다. 초음파처리는 140 W/L의 조사밀도에서 가용화율이 가장 높았으며(33~39%), 조사주기의 증대는 가용화율에 큰 영향을 미치지 않는 것으로 확인되었다. 알칼리 처리와 초음파처리를 혼재한 병합처리 시 알칼리처리 후 초음파처리를 적용한 방법이 $70.4{\pm}9.4%$의 가용화율로 초음파처리 후 알칼리처리 방법에 비해 약 22% 높은 결과를 나타내었다. 각 조건에서의 SCOD 증가속도는 병합처리(알칼리처리 후 초음파처리)에서 0.076 $min^{-1}$으로 가장 높은 결과를 나타내었다.

• International Journal of Contents
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• 제11권1호
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• pp.62-68
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• 2015

Many severe earthquakes have occurred along the main fault lines in the world. In recent years, there has been a high incidence of small- and large-scale earthquakes in our country. These occurrences of earthquakes have become increasingly serious, owing to a degrading earth environment. An earthquake, in general, causes far more serious damages like disruptions in electricity or gas facilities, and fire disasters from its annexed effects than by its vibrations or the shock itself. In this paper, we present a countermeasure and its necessity in safeguarding against fire disasters in regional heritage villages such as "Asan Oeam," "Jeonju Hanok," and "Andong Hahoe." A more systematic and effective strategy for prevention systems against severe fire disasters is proposed after performing various related investigations and analyses of existing domestic and international systems. We investigated the existing fire security systems and their historical records with the tendency of earthquake occurrences in these three folk villages. In this proposal, we present a strategic approach for safeguarding against fire damages in our regional heritage villages derived from ICT (information communication technology)-based DPD (disaster prevention design), after examining the laws and regulations of fire-prevention strategies in Japan, America, and Europe.

• International Journal of Contents
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• 제12권3호
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• pp.34-41
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• 2016

A traditional village is cultural property where old buildings and traditions are concentrated and also where indigenous traditional cultures can be recognized and experienced directly or indirectly. In addition, traditional villages have been recognized as precious resources to revitalize regional economies through tourism. Currently, signage systems have been developed as for ordinary tourist sites or cities, and concepts or methods for sign system for traditional villages have not yet been established. Therefore, it is necessary to develop disaster prevention-based signage to prevent large-scale disasters, to guarantee the safety of residents, and to increase the satisfaction of visitors in traditional villages as precious resources. A case study is conducted to apply the proposed sign system for traditional villages in Korea and Japan as a tourist-oriented sign system that has been accomplished in Korea and a large disaster-oriented sign system developed with residents as a priority in Japan. The disaster prevention sign system considers the residents since residents are victims when a disaster happens, and guideline to increase the efficacy and satisfaction are suggested. However, this study has definite limits in sucring objectivity because the objects of study are insufficient, and the development of the sign system based on effective disaster prevention considering the features of traditional villages will continue in the future.

• International Journal of Contents
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• 제11권2호
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• pp.31-36
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• 2015

Recent years have seen a significant increase in demand for multimedia data over wireless sensor networks for monitoring applications that utilize sensor nodes to collect multimedia data, including sound and video. However, the multimedia streams generate a very large amount of data. When data transmission schemes for traditional wireless sensor networks are applied in wireless multimedia sensor networks, the network lifetime significantly decreases due to the excessive energy consumption of specific nodes. In this paper, we propose a data compression scheme that implements the Chinese remainder theorem to a wireless multimedia sensor network. The proposed scheme uses the Chinese Remainder Theorem (CRT) to compress and split multimedia data, and it then transmits the bit-pattern packets of the remainder to the base station. As a result, the amount of multimedia data that is transmitted is reduced. The superiority of our proposed scheme is demonstrated by comparing its performance to that of an existing scheme. The results of our experiment indicate that our proposed scheme significantly increased the compression ratio and reduced the compression operation in comparison to those of existing compression schemes.

• 한국동물위생학회지
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• 제36권2호
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• pp.95-103
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• 2013

The hazard analysis critical control point (HACCP) system was introduced to the Korean livestock slaughter and product processing business in 1997. Ice cream manufacturers focus on the sterilization process in order to reduce microorganism, so the HACCP-accredited ice cream manufacturers particularly set the sterilization process as critical control point (CCP). Therefore, the microbiological test results on the finished products can be considered as one of the indicators which show the level of microbiological control in the ice cream manufacturers. Accordingly, this study was carried out to examine if there is a meaningful difference in terms of the microbiological control level between the HACCP-accredited and non-accredited ice cream manufacturer groups by comparing aerobic plate count (APC) of ice creams. The mean of APC was 1.68 Log CFU/g in the HACCP-accredited ice cream manufacturer group and 2.59 Log CFU/g in the non-accredited ones respectively and there was a statistically significant difference (P<0.05). The test results suggest that the level of microbiological control in the HACCP-accredited ice cream manufactures is much higher than that of non-accredited ones.

• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.43-49
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• 1998

The availability of large quantities of waste woods provides an impetus for investigating woody biomass potential uses. Polyurethane (PU) foams are prepared with reacting isocyanates and polyols, and are used. in various industry fields. Thus, lignocellulosic waste raw-materials are proposed as replacement for synthetic polyol to PU foam formulation. In this study PU foams were manufactured from liquefied woods, methanediisocyanate(MDI), catalyst, foaming stabilizer, and viscosity aids. The polyol content, isocyanate.hydroxyl group (NCO/OH) ratio, and water content were varied to evaluate their effects on the foaming and water absorption of the PU foams. Less than 400 Molecular weight. of polyethylene glycol(PEG) and 1 to 3 solvent to woody raw-material ratio were desirable for liquefying woody materials. Liquefying rate was increased with more than 3 % addition of inorganic and organic catalysts and raising reaction temperature more than $150^{\circ}C$. Addition of starch enhanced liquefying of woody materials. Fourty percents of starch resulted in about 90% liquefying rates. Foaming rates were increased with increasing moisture contents of liquefied wood. Moisture contents of 0.6% resulted in 5 time-foaming rates, and seven percents of moisture contents more than 30 time-foaming rates. But, an increase in water content may result in a decrease in cross-links between wood polyol and isocyanate, because the NCO/OH ratio is constant. Increasing moisture contents have significantly decreased density of PU foams. The optimum water content should be about 2.5% or less in this adopted condition.