• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.200-207
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• 2016

The automotive seat is an important component that moves in sync with the driver and is actively being developed with various new functions. The aim of this work is to develop a lightweight seat cushion extension module using a lightweight material. To this end, a structural strength analysis, vertical strength test, and durability test were conducted. In the structural analysis, the maximum value of deformation under vertical load was 4.98 mm at the front of the upper panel. The maximum stress was approximately 105 MPa, which occurred at the point of contact between the upper and lower panels of the module. The vertical strength test showed a maximum vertical deformation of 5.31 mm under a vertical load, which differed from the analysis results by approximately 6.45%. The structural safety of the product was verified by the fact that it showed no harmful deformation or damage during operation after the vertical strength test and a durability test for 20,000 cycles. Furthermore, the use of engineering plastics made it possible to reduce the weight by approximately 30% compared to existing products. The lack of damage after tests verified the passenger safety, strength, and rigidity of the product. The results are expected to be applied for improving environmental and fuel efficiency regulations and preventing accidents due to driver fatigue. The applications of this module could be expanded various types of vehicles, as well as other industries in which eco-friendly and lightweight materials are used.

• Composites Research
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• v.16 no.3
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• pp.25-31
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• 2003

In this work the effect of surface treated SiC on thermal stability and mechanical interfacial properties of carbon fiber/epoxy resin composites. The surface properties of the SiC were determined by acid/base values and contact angles. The thermal stabilities of carbon fiber/epoxy resin composites were investigated by TGA. The mechanical interfacial properties of the composites were studied in ILSS, critical stress intensity factor ($\textrm{K}_{IC}$), and critical strain energy release rate($\textrm{G}_{IC}$) measurements. As a result, the acidically treated SiC(A-SiC) had higher acid value than untreated SiC(V-SiC) or basically treated SiC(B-SiC). According to the contact angle measurements, it was observed that chemical treatments led to an increase of surface free energy of the SiC surfaces, mainly due to the increase of the specific(polar) component. The mechanical interfacial properties of the composites including ILSS, $\textrm{K}_{IC}$, and $\textrm{G}_{IC}$ had been improved in the specimens treated by chemical solutions. These results were explained that good wetting played an important role in improving the degree of adhesion at interfaces between SiC and epoxy resin matrix.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.1-12
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• 2006

An existing Steel pipe, Cast iron pipe and Concrete pipe is can not escaped from aging, specially Metal tube is causing many problems that the quality of water worse is concerned about many rust and mike efficient use of preservation of water. The use of Glassfiber Reinforced Plastic Pipe(GRP PIPE) should be one of the possible scheme to get over these problems. The GRP PIPE has an excellent resistance power and the life is lasting from 50 to 100 years roughly. It's to be useful as a result of high durability and a good construction work also it is a light weight therefore can be expected to short the time of construction and man power. In this research, to executed the small-scaled model test, in-situ model test using CLSM of in-situ soil and to evaluated the stress - strain of the pipe also try to estimated how useful is. From the model test in laboratory, the vertical and horizontal deformation of the GRP PIPE measured in six instance using 200mm and 300mm in diameters. The value of experimentation, theory, analysis got the same results of the test, but the vertical and horizontal deformation gauged in small and the earth pressure was almost zero using CLSM of in-situ soil..

• Journal of Korean Society of Water and Wastewater
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• v.34 no.3
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• pp.211-220
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• 2020

When domestic sewage and rainwater runoff are discharged into a single sewer pipe, it is called a "combined sewer system." The sewage design standards in Korea specify the flow velocity based only on the volume of rainfall; therefore, sedimentation occurs on non-rainy days owing to the reduced flow rate and velocity. This sedimentation reduces the discharge capacity, causes unpleasant odors, and exacerbates the problem of combined sewer overflow concentration. To address this problem, the amount of sewage on non-rainy days, not just the volume of rainfall, should also be considered. There are various theories on sedimentation in sewer movement. This study introduces a self-cleansing velocity based on tractive force theory. By applying a self-cleansing velocity equivalent to the critical shear stress of a sand particle, sedimentation can be reduced on non-rainy days. The amount of sewage changes according to the water use pattern of citizens. The design hourly maximum wastewater flow was considered as a representative value, and the velocity of this flow should be more than the self-cleansing velocity. This design method requires a steeper gradient than existing design criteria. Therefore, the existing sewer pipelines need to be improved and repaired accordingly. In this study, five types of improvement and repair methods that can maximize the use of existing pipelines and minimize the depth of excavation are proposed. The key technologies utilized are trenchless sewer rehabilitation and complex cross-section pipes. Trenchless sewer rehabilitation is a popular sewage repair method. However, it is complex because the cross-section pipes do not have a universal design and require continuous research and development. In an old metropolis with a combined sewer system, it is difficult to carry out excavation work; hence, the methods presented in this study may be useful in the future.

• Journal of Life Science
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• v.25 no.12
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• pp.1458-1469
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• 2015

Many organic solvent-tolerant bacteria have been isolated from all environments such as soil, waste-water, even deep sea after first isolation report of organic solvent-tolerant bacterium. Most organic solvent- tolerant isolates have been determined to be Gram-negative bacteria, because Gram-negative bacteria have inherent tolerance property toward hostile organic solvents more than Gram-positive bacteria. The mechanisms of organic solvent tolerance have been elucidated extensively using mainly organic solvent-tolerant Gram-negative bacteria. The solvent-tolerance mechanisms in Gram-positive bacteria can be found in comparatively recent research. Organic solvents exhibited different toxicity depending on the solvent, and the tolerance levels of organic solvent-tolerant bacteria toward organic solvents were also highly changeable among species and strains. Therefore, organic solvent-tolerant bacteria could coped with solvent toxicity and adapted to solvent stress through the multifactorial and multigenic adaptative strategies. They could be survived even in the hyper concentrations of organic solvents by mechanisms which include: changes in cell morphology and cell behaviour, cell surface modifications, cell membrane adaptations, solvent excretion pumps, chaperones and anti-oxidative response. The aim of this work is to review the representative solvent tolerant bacteria and the adaptative and tolerance strategies toward organic solvents in organic solvent-tolerant bacteria, and their potential industrial and environmental impact.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.23-29
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• 1989

Biochemical consequence of the accumulation in cells of superoxide $(O^{-}_{2})$ which was proposed to be probably a common chemical factor in the secondary process of the mechanism of chilling injury as well as in the visible light photodamage in cells of higher plants, has been investigated in the present work. Especially focused was the destructive effect of $O^{-}_{2}$ on the biochemical activity of mitochondria, as informations which support the suggestion that mitochondrial inner membrane is the major site of $O^{-}_{2}$ production have been collected. Mitochondria and submitochondrial particles (SMP) were prepared from soybean hypocotyls for this case study. When SMP were treated with the electrolytically produced $O^{-}_{2}$ they suffered not only inhibition of the membrane-bound enzymes as demonstrated by cytochrome c oxidase, but also lipid peroxidation of membrane as proved by malondialdehyde production. Malate dehydrogenase present in the protein extract from mitochondrial matrix was also inhibited by the $O^{-}_{2}$ treatment. These results exhibited the chaotic effect of the overproduction and accumulation of $O^{-}_{2}$ in cells under a certain abnormal circumstance such as environmental stress on the physiological function of mitochondrial; disruption of the cellular metabolic pathways and the structural integrity of membrane.

• Journal of Oriental Neuropsychiatry
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• v.31 no.3
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• pp.197-211
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• 2020

Objectives: The purpose of this study was to introduce the progress of treatment and improve clinical use after conducting Mentalizing the Rooms of Mind, the main technique of Mindfulness & Loving Beingness psychotherapy, for a patient with panic disorder. Methods: We conducted a Mentalizing the Rooms of Mind for 10 sessions on an age 23 female diagnosed with panic disorder based on the DSM-5 diagnostic criteria. After receiving consent from the subject, through chart review, the progress of treatment was observed focusing on the MMPI-2 and CSEI-s (The Core Seven Emotions Inventory-short form) conducted pre- and post-treatment. This study was approved by the Institutional Review Board of Wonkwang University Sanbon Hospital (WMCSB202007-55). Results: 1. The MMPI-2 clinical scales of an age 23 female with panic disorder showed a 7 (Pt)-1 (Hs)-3 (Hy) profile pre-treatment, but for post-treatment, the scale showed 1 (Hs)-3 (Hy) profile, and the 7 (Pt) scale showed significant decline. In the MMPI-2 reconstructed clinical scales, RC7 (Dysfunctional Negative Emotions) and RC8 (Aberrant Experiences) showed significant decline. 2. In the pre- and post-treatment MMPI-2 content scales, Anxiety, Fears, Obsessiveness, Social Discomfort, and Work Interference scores decreased, showing overall positive stability. On the MMPI-2 supplementary scales, the Anxiety and Post-Traumatic Stress Disorder scores decreased, and the Ego Strength increased, resulting in improved overall psychological adaptation. 3. Pre- and post-treatment of an age 23 female with panic disorder, CSEI-s showed significant decline of 恐, 驚, 悲, and 思. So it seems that the emotions caused by Chiljeongsang (七情傷) were more stable than before treatment. Conclusions: As shown above, the treatment of panic disorder through Mentalizing the Rooms of Mind, a major technique of Mindfulness & Loving Beingness psychotherapy, showed positive changes in MMPI-2 as well as improvement of the subjective symptoms. Thus, Mentalizing the Rooms of Mind has high clinical use, and it seems that it is necessary to create a manual for this in the future.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.146-156
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• 2018

Spermidine is a naturally occurring polyamine compound that has recently emerged with anti-aging properties and suppresses inflammation and oxidation. However, its mechanisms of action on anti-inflammatory and antioxidant effects have not been fully elucidated. In this study, the potential of spermidine for reducing pro-inflammatory and oxidative effects in lipopolysaccharide (LPS)-stimulated macrophages and zebrafish was explored. Our data indicate that spermidine significantly inhibited the production of pro-inflammatory mediators such as nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$), and cytokines including tumor necrosis $factor-{\alpha}$ and $interleukin-1{\beta}$ in RAW 264.7 macrophages without any significant cytotoxicity. The protective effects of spermidine accompanied by a marked suppression in their regulatory gene expression at the transcription levels. Spermidine also attenuated the nuclear translocation of $NF-{\kappa}B$ p65 subunit and reduced LPS-induced intracellular accumulation of reactive oxygen species (ROS) in RAW 264.7 macrophages. Moreover, spermidine prevented the LPS-induced NO production and ROS accumulation in zebrafish larvae and was found to be associated with a diminished recruitment of neutrophils and macrophages. Although more work is needed to fully understand the critical role of spermidine on the inhibition of inflammation-associated migration of immune cells, our findings clearly demonstrate that spermidine may be a potential therapeutic intervention for the treatment of inflammatory and oxidative disorders.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.122-129
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• 2008

The purpose of this work was to investigate the synergically bactericidal effects and cellular responses of green tea polyphenols (TPPs) and nalidixic acid (NA) on nalidixic acid-resistant (NAR) Salmonella typhimurium. The bactericidal activities of $>3,500{\mu}g/ml$ TPPs and $<256{\mu}g/ml$ NA were investigated for S. typhimurium of which initial cell number was approximately adjusted to 107 cell/ml. Complete elimination of NAS-S. typhimurium was achieved within 6 hr of incubation at the concentrations of $3,500{\mu}g/ml$ TPP or $256{\mu}g/ml$ NA, whereas only partial bactericidal effect was achieved under the same conditions. However, the combinations of $3,000{\mu}g/ml$ TPPs and $32{\mu}g/ml$ NA against NAS-S. typhimurium and $3,500{\mu}g/ml$ TPPs and $64{\mu}g/ml$ nalidixic acid against NAR-S. typhimurium showed complete removal within 5 hr of incubation. The stress shock proteins (SSPs) were induced at different concentrations of TPP o rNA used as stressors against cell culture of S. typhimurium. The proteins were identified as 70-kDa DnaK and 60-kDa GroEL by SDS-PAGE and Western blot. SSPs induced by the stressors were found to increase in proportion to the TPPs or NA. Scanning electron microscopy analyses revealed the presence of perforations and irregular rod shape with wrinkled surfaces for cells treated with TPPs or NA.

• Journal of Biosystems Engineering
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• v.38 no.2
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• pp.138-148
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• 2013

Purpose: Determining an appropriate path is a top priority in order for a robot to maneuver in a dynamically efficient way especially in a pick-and-place task. In a non-standardized work environment, current robot arm executes its motion based on the kinematic displacements of joint variables, though resulting motion is not dynamically optimal. In this research we suggest analyzing and applying motion patterns of the human arm as an alternative to perform near optimum motion trajectory for arbitrary pick-and-place tasks. Methods: Since the motion of a human arm is very complicated and diverse, it was simplified into two links: one from the shoulder to the elbow, and the other from the elbow to the hand. Motion patterns were then divided into horizontal and vertical components and further analyzed using kinematic and dynamic methods. The kinematic analysis was performed based on the D-H parameters and the dynamic analysis was carried out to calculate various parameters such as velocity, acceleration, torque, and energy using the Newton-Euler equation of motion and Lagrange's equation. In an attempt to assess the efficacy of the analyzed human motion pattern it was compared to the virtual motion pattern created by the joint interpolation method. Results: To demonstrate the efficacy of the human arm motion mechanical and dynamical analyses were performed, followed by the comparison with the virtual robot motion path that was created by the joint interpolation method. Consequently, the human arm was observed to be in motion while the elbow was bent. In return this contributed to the increase of the manipulability and decrease of gravity and torque being exerted on the elbow. In addition, the energy required for the motion decreased. Such phenomenon was more apparent under vertical motion than horizontal motion patterns, and in shorter paths than in longer ones. Thus, one can minimize the abrasion of joints by lowering the stress applied to the bones, muscles, and joints. From the perspectives of energy and durability, the robot arm will be able to utilize its motor most effectively by adopting the motion pattern of human arm. Conclusions: By applying the motion pattern of human arm to the robot arm motion, increase in efficiency and durability is expected, which will eventually produce robots capable of moving in an energy-efficient manner.