• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.207-215
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• 2018

In this study, targeting KOSPI and KOSDAQ listed companies, the relationship between the abnormal investment of companies and analyst earnings forecasts was empirically analyzed. The analysis period of this study spanned from 2003 to 2015 (with that of dependent variables spanning from 2004 to 2016) based on the variables of interest, and among the companies whose earnings per share forecasts were announced by financial analysts, the final sample of 4,917 companies/year that meets the research condition was selected as the target analysis. The results of the empirical analysis are as follows. First, it turned out that the more total abnormal investment, abnormal R&D and abnormal CAPEX investment, the more accurate were analyst earnings forecasts. Second, the more total abnormal investment, abnormal R&D, abnormal CAPEX investment, the more pessimistic analyst earnings forecasts tended to be. Further analysis has shown that these results came more from over investment groups than under investment groups. The results of this study are expected to make additional contributions to the existing studies in that the abnormal investment is considered as a determinant of analyst earnings forecasts.

• Journal of the Korea Convergence Society
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• v.9 no.12
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• pp.485-493
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• 2018

This study analyzed the motivational interviewing of type 2 diabetes patients in order to understand the difficulties and motivations associated with starting insulin treatment in psychosomatic insulin-resistant patients. The method used the consistent comparative analysis. The results of study were as follows: building relationships, focusing (Self-explore of problems with diabetes self-management, Recognizing the limitations of diabetes management, Concerns about complications, Imagine the future), inducing (Imagine the expected benefits and disadvantages of insulin administration, Discovering the benefits of insulin, Changes in thinking about starting insulin therapy), planning (Show specific curiosity about change, Planning change), maintaining change behavior (Keeping change confident), and evaluating. This study will contribute to understanding patients with type 2 diabetes with psychological insulin resistance. It may also provide implications for professionals helping these subjects.

• Membrane Journal
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• v.29 no.1
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• pp.1-10
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• 2019

Poly(ether block amide) (PEBA) is one of the commercially important class of block copolymer very much suitable specifically for $CO_2$ separation. Gas separation membrane need to have good mechanical strength as well as high gas permeability. The crystalline polyamide (PA) block provides the mechanical strength while the rubbery polyether (PE) group being $CO_2$-philic facilitate $CO_2$ permeation though the membrane. Composition of thermoplastic and rubbery phase in the polymer are changed to fit into suitable gas separation application. Although PEBA has good permeability, the selectivity of the membrane can be enhanced by incorporating molecular sieve without affection much the gas permeability. Mixed matrix membrane (MMM), a class of composite membrane combine the advantage of polymer matrix with the inorganic fillers. However, there are some disadvantages based on the compatibility of the inorganic fillers and polymeric phase. This review covers both the advantage and limitations of PEBA block copolymer based composite membrane.

• Membrane Journal
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• v.30 no.6
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• pp.450-459
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• 2020

Membrane-based separations have the potential to reduce energy consumption and environmental impact associated with conventional processes. However, many researches have been done to develop new membrane materials with greater selectivity and permeability. Here, we report highly selective membranes by introducing bulky ethyl substituents into the polyimide. The ethyl group in the ortho position to the imide nitrogen interferes the chain packing and increases chain stiffness and the distance between the polymer chains. The polyimide membranes were synthesized from various aromatic dianhydrides and 4,4'-methylenebis(2,6-diethylaniline) (MDEA). The synthesized membranes with increased gas diffusion length due to bulky substituents showed improved propylene/propane (C3H6/C3H8) selectivity. Single gas permeation showed high C3H6/C3H8 selectivity of 14.5, and C3H6 permeability of 7.0 barrer was found in MDEA-polyimide. Mixed-gas permeation results also demonstrate that MDEA-polyimide can achieve high selectivity in mixed-gas environment. Furthermore, this approach could significantly increase the feasibility of economic propylene separation compared to conventional polymer materials.

• Membrane Journal
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• v.32 no.1
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• pp.74-82
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• 2022

The objective of this work was to investigate the gas permeation properties of CO₂ and CH₄ for PEBAX^®/TS-530 hybrid membranes and compare with pure PEBAX^®-1657 membrane. With FTIR and XRD it was possible to confirm that TS-530 was dispersed well in PEBAX^® matrix. Compared with pure PEBAX^® membrane, ideal separation factor for PEBAX^®/TS-530 (10 wt%) hybrid membrane was enhanced a little. As the amount of TS-530 was increased, the gas permeability coefficients of both CO₂ and CH₄ were increased, while the ideal separation factor was decreased. This results were explained by the reduction of crystallinity of polyamide block and interchain distance caused by introduction of inorganic nanoparticles. And fumed silica might tend to agglomerate, resulting in forming nonselective nanogaps in the hybrid materials, thus the diffusivity would be enhanced at the expense of diffusivity selectivity.

• Composites Research
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• v.37 no.1
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• pp.40-45
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• 2024

In this research, we introduce a novel approach that employs a 3D convolutional neural network (CNN) model to predict the permeability of Gas Diffusion Layers (GDLs). For training the model, we create an artificial dataset of GDL representative volume elements (RVEs) by extracting morphological characteristics from actual GDL images obtained through X-ray tomography. These morphological attributes involve statistical distributions of porosity, fiber orientation, and diameter. Subsequently, a permeability analysis using the Lattice Boltzmann Method (LBM) is conducted on a collection of 10,800 RVEs. The 3D CNN model, trained on this artificial dataset, well predicts the permeability of actual GDLs.

• Clinical and Experimental Pediatrics
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• v.48 no.9
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• pp.960-968
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• 2005

Purpose : This multi-center, open-label, clinical study was designed to evaluate the safety and immunogenicity of a trivalent, live, attenuated measles-mumps-rubella(MMR) vaccine, $Priorix^{TM}$ in Korean children. Methods : From July 2002 to February 2003, a total of 252 children, aged 12-15 months or 4-6 years, received $Priorix^{TM}$ at four centers : Han-il General Hospital, Kyunghee University Hospital, St. Paul's Hospital at the Catholic Medical College in Seoul, and Korea University Hospital in Ansan, Korea. Only subjects who fully met protocol requirements were included in the final analysis. The occurrence of local and systemic adverse events after vaccination was evaluated from diary cards and physical examination for 42 days after vaccination. Serum antibody levels were measured prior to and 42 days post-vaccination using IgG ELISA assays at GlaxoSmithKline Biologicals (GSK) in Belgium. Results : Of the 252 enrolled subjects, a total of 199 were included in the safety analysis, including 103 from the 12-15 month age group and 96 from the 4-6 year age group. The occurrence of local reactions related to the study drug was 10.1 percent, and the occurrence of systemic reactions was 6.5 percent. There were no episodes of aseptic meningitis or febrile convulsions, nor any other serious adverse reaction. In immunogenicity analysis, the seroconversion rate of previously seronegative subjects was 99 percent for measles, 93 percent for mumps and 100 percent for rubella. Both age groups showed similar seroconversion rates. The geometric mean titers achieved, 42 days pos-tvaccination, were : For measles, in the age group 12-15 months, 3,838.6 mIU/mL [3,304.47, 4,458.91]; in the age group 4-6 years, 1,886.2 mIU/mL [825.83, 4,308.26]. For mumps, in the age group 12-15 months, 956.3 U/mL [821.81, 1,112.71]; in the age group 4-6 years, 2,473.8 U/mL [1,518.94, 4,028.92]. For rubella, in the age group 12-15 months, 94.5 IU/mL [79.56, 112.28]; in the age group 4-6 years, 168.9 IU/mL [108.96, 261.90]. Conclusion : When Korean children in the age groups of 12-15 months or 4-6 years were vaccinated with GlaxoSmithKline Biologicals' live attenuated MMR vaccine ($Priorix^{TM}$), adverse events were limited to those generally expected with any live vaccine. $Priorix^{TM}$ demonstrated excellent immunogenicity in this population.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.295-302
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• 2012

The coagulation of combined sewer overflows ($CSO_{s}$) was investigated by jar-testing with several commercial coagulants. $CSO_{s}$ sample showed different characteristics of coagulation from secondary wastewater with three common coagulants, aluminum sulfate, ferric chloride and polyaluminum chloride (PACl). Jar-tests showed that relatively wide range of optimal SS and T-P removal yielded with alum and ferric chloride compared with cationic polymers, though efficient SS and T-P removal can be achieved with all three coagulants. The decrease of pH was caused by the increase in dosage of aluminum sulfate, ferric chloride and PACl as coagulants. The pH was changed from 7.0 to 4.7 with the dosages of ferric chloride 25 mL/L. Aluminum sulfate revealed pH of 5.0 and PACl was highest pH of 5.4 after dosing of coagulants. The optimal pH to treat $CSO_{s}$ with aluminum sulfate were 6-6.5; with PACl 6-7, and with ferric chloride higher than 7.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.451-456
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• 1998

By grafting acrylic acid, fumalic acid and maleic acid onto chitosan, graft copolymers, CsAa, CsFa and CsMa, respectively were prepared for potential uses as flocculants in waste water treatment. When 40 ppm of each grafted chitosan sample was added into the waste water, CsMa showed the best removal rate of COD and suspended solids(SS), followed by CsFa and CsAa and chitosan. The transmittance and removal rate of COD and SS were the highest at pH 5. All grafted chitosan exhibited better performance than chitosan itself, resulting from the amphiphilic property of grafted chitosan copolymer with carboxy groups.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.99-99
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• 1997

현재까지 NSAID 및 SAID의 사용으로 급성염증의 경우는 잘 조절되고 있으나, 류마티스 관절염과 같은 만성염증성 질환은 극복하지 못하였다. 뿐 만 아니라, 상기의 약물들의 장기간 사용으로 인한 부작용이 문제되고 있다. 그러므로, 만성염증성 질환의 치료를 위한 새로운 계열의 항염증제 개발이 시급하며, 많은 연구자들이 여러 가지 식물추출물을 이용하여 신약개발의 가능성을 타진하고 있다. 이의 일환으로, 본 연구에서는 고전문헌에서 사용된 식물들을 대상으로 하여 Rat의 류마티스 관절염 model을 이용하여 그들의 항염증작용을 연구하였다. 여정자 및 등줄나무를 포함한 27종의 식물을 이용하여 각 methanol 추출물을 조제하고, 매일 경구로 투여하였다 (200 mg/kg/day). 류마티스성 관절염은 rat의 족부에 Mycobacterium butyricum (0.6 mg/rat)을 주사하여 유발시켰고, 2차부종의 억제를 추출물의 활성으로 판정하였다. 그 결과, 27종의 식물중 목통, 마황 및 산두근이 2차부종을 유의성있게 억제하였으며, adjuvant 주사 후 16일에 억제율이 각각 22%, 36%, 13%로 나타났다. 산두근을 분획하여 재검정한 결과 50 mg/kg/day의 용량으로 투여시 EtOAc 및 n-butanol 분획에서 억제능이 나타나, 이들 분획을 대상으로 활성물질의 분리를 계속하고 있다.