• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.2
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• pp.199-208
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• 2008

In this paper, to analyze the initial valued non-homogeneous elastic half space by the scaled boundary analysis, the infinite element approach was introduced. The free surface of the initial valued non-homogeneous elastic half space was modeled as a circumferential direction of boundary scaled boundary coordinate. The infinite element was used to represent the infinite length of the free surface. The initial value of material property(elastic modulus) was considered by the combination of the position of the scaling center and the power function of the radial direction. By use of the mapping type infinite element, the consistent elements formulation could be available. The performance and the feasibility of proposed approach are examined by two numerical examples.

• Structural Engineering and Mechanics
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• v.90 no.4
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• pp.357-370
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• 2024

Due to the fact that the mechanism of the effects of temperature and initial geometric imperfection on low-velocity impact problem of axially moving plates is not yet clear, the present paper is to fill the gap. In the present paper, the nonlinear dynamic behavior of axially moving imperfect graphene platelet reinforced metal foams (GPLRMF) plates subjected to lowvelocity impact in thermal environment is analyzed. The equivalent physical parameters of GPLRMF plates are estimated based on the Halpin-Tsai equation and the mixing rule. Combining Kirchhoff plate theory and the modified nonlinear Hertz contact theory, the nonlinear governing equations of GPLRMF plates are derived. Under the condition of simply supported boundary, the nonlinear control equation is discretized with the help of Gallekin method. The correctness of the proposed model is verified by comparison with the existing results. Finally, the time history curves of contact force and transverse center displacement are obtained by using the fourth order Runge-Kutta method. Through detailed parameter research, the effects of graphene platelet (GPL) distribution mode, foam distribution mode, GPL weight fraction, foam coefficient, axial moving speed, prestressing force, temperature changes, damping coefficient, initial geometric defect, radius and initial velocity of the impactor on the nonlinear impact problem are explored. The results indicate that temperature changes and initial geometric imperfections have significant impacts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.810-817
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• 2014

Two consecutive feeding trials were conducted to evaluate the effects of extruded pellet (EP) and raw fish-based moist pellet (MP) in the juvenile (experiment I) and sub-adult (experiment II) stages of olive flounder, Paralichthys olivaceus. The fish were distributed randomly to three aquarium tanks, as a group of 1,200 fish (initial mean weight $13.5{\pm}1.76g$) in experiment I, and as a group of 390 fish (initial mean weight $385{\pm}15.3g$) in experiment II. In experiment I, the weight gain, specific growth rate, feed efficiency, protein efficiency ratio, and survival of fish fed EP were all significantly higher than those of fish fed MP. In experiment II, no significant differences were observed in weight gain, specific growth rate and survival between the EP and MP groups. However, the feed efficiency and protein efficiency ratios of fish fed EP were significantly higher than those of fish fed MP. The results of this study indicate that EP could be developed to replace MP for market size production of olive flounder without any adverse effects on the growth performance. The dietary formulation used in this study could be used as an appropriate feed for olive flounder.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.979-982
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• 2008

We studied hybrid passivation using parylene-C, metal, photoacyl and indium zinc oxide for pentacene OTFT to assure stability in subthreshold region. After the passivation, the changes in S and $V_{on}$ of OTFT were negligible and $I_{off}$ maintained its initial value of ${\sim}10^{-12}$ A. Therefore, the hybrid passivation is suitable for practical applications based on OTFT.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.247-249
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• 2008

Low Temperature a-Si:H TFT on stainless steel substrate has been developed for the flexible electrophoretic display. Stability of low temperature a-Si:H TFT is more important point than its initial device characteristics. Thus, we have studied device characteristics of low temperature a-Si:H TFT in terms of stability for driving electrophoretic display.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.8-13
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• 2018

The light weight composite materials have been replacing in high performance structures. The object of this study is to examine the effects of the initial crack location about a delamination in a PVC foam cored sandwich composite that is used for the strength improvement of structures. The initial crack location and fiber laminates thickness were changed with several types. The MMB specimen was used for evaluating the fracture toughness and crack behaviors. The material used in the experiment is a commercial twill carbon prepreg in CFRP material and Airex in PVC foam core. Sandwich laminate composites are composed by PVC foam core layer between CFRP face sheets. The face sheets were fabricated as 2 types of 5 and 8 plies. The initial cracks were located in a PVC form core and the interface of upper CFRP sheet. From the results, the crack initiation was affected with the location of the initial crack inserted in the PVC foam core. Among them, the initial crack at 1/3 of the upper part of the PVC foam core was the most rapid progression. And the critical energy release rate was $0.40kJ/m^2$, which is the lowest value when the initial crack was inserted into the interface between a PVC foam core and CFRP laminated with 5 plies. Meanwhile, the highest value of $1.27kJ/m^2$ was obtained when the initial crack was located at the center line in case of the 8 plies.

• Journal of Audiology & Otology
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• v.25 no.4
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• pp.209-216
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• 2021

Background and Objectives: We aimed to analyze treatment outcomes following different initial management approaches and confirm treatment regimens for acute low-tone sensorineural hearing loss (ALHL) that would yield the best results. Subjects and Methods: We retrospectively analyzed the medical records of 106 patients with ALHL who visited a university hospital's otology clinic from March 2013 to June 2019. Pure-tone averages at the initial visit and at 2 and 4 weeks after the initial visit were evaluated. Results: Forty-nine patients were enrolled in this study; of them, 41 (83.7%) exhibited complete recovery (CR) at 2 weeks and 43 (87.8%) exhibited CR at 1 month after the initial visit. Regression analysis revealed that CR at 2 weeks after the initial visit was associated with diuretic use [Exp(B): 10.309, 95% confidence interval (CI): 1.007-100]. An initial daily low-dose steroid use was marginally significant [Exp(B): 1.042, 95% CI: 0.997-1.092; p=0.066]. Isolated diuretic use [Exp(B): 25.641, 95% CI: 1.121-90.909; p=0.039] was an independent, good prognostic factor at 1 month after the initial visit. However, other treatment regimens did not affect the final results. Conclusions: A combination of initial daily administration of ≤30 mg prednisolone plus diuretics was sufficient as the first-line treatment for ALHL. High-dose steroids and salvage intratympanic steroid injections can be applied as a second choice; however, the predicted outcome would not be good in that case.

• Korean Journal of Audiology
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• v.25 no.4
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• pp.209-216
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• 2021

Background and Objectives: We aimed to analyze treatment outcomes following different initial management approaches and confirm treatment regimens for acute low-tone sensorineural hearing loss (ALHL) that would yield the best results. Subjects and Methods: We retrospectively analyzed the medical records of 106 patients with ALHL who visited a university hospital's otology clinic from March 2013 to June 2019. Pure-tone averages at the initial visit and at 2 and 4 weeks after the initial visit were evaluated. Results: Forty-nine patients were enrolled in this study; of them, 41 (83.7%) exhibited complete recovery (CR) at 2 weeks and 43 (87.8%) exhibited CR at 1 month after the initial visit. Regression analysis revealed that CR at 2 weeks after the initial visit was associated with diuretic use [Exp(B): 10.309, 95% confidence interval (CI): 1.007-100]. An initial daily low-dose steroid use was marginally significant [Exp(B): 1.042, 95% CI: 0.997-1.092; p=0.066]. Isolated diuretic use [Exp(B): 25.641, 95% CI: 1.121-90.909; p=0.039] was an independent, good prognostic factor at 1 month after the initial visit. However, other treatment regimens did not affect the final results. Conclusions: A combination of initial daily administration of ≤30 mg prednisolone plus diuretics was sufficient as the first-line treatment for ALHL. High-dose steroids and salvage intratympanic steroid injections can be applied as a second choice; however, the predicted outcome would not be good in that case.

• Proceedings of the KSRS Conference
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• v.2
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• pp.917-917
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• 2006

• Tuberculosis and Respiratory Diseases
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• v.77 no.6
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• pp.271-273
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• 2014

Disease flare-up after discontinuing epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) has been considered as a critical issue in lung cancer patients who have experienced radiologic progression after showing initial durable response. This is a case of systemic nocardiosis that occurred after chronic steroid use for radionecrosis from stereotactic radiosurgery. It was initially thought as a disease flare-up after stopping EGFR-TKI.