• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.48.1-48.1
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• 2009

Performance of organic field-effect transistors (OFETs) with various temperature-cured polyacrylate(PA) copolymer as a gate insulator was studied. The PA thin film, which was cured at an optimized temperature, showed high dielectric strength (>7 MV/cm), low leakage current density ($5{\times}10^{-9}\;A/cm^2$ at 1 MV/cm) and enabled negligible hysteresis in MIS capacitor and OFET. A field-effect mobility of ${\sim}0.6\;cm^2/V\;s$, on/off current ratio (Ion/Ioff) of ${\sim}10^5$ and inverse subthreshold slope (SS) as low as 1.22 V/decwere achieved. The high dielectric strength made it possible to scale down the thickness of dielectric, and low-voltage operation of -5 V was successfully realized. The chemical changes were monitored by FT-IR. The morphology and microstructure of the pentacene layer grown on PA dielectrics were also investigated and correlated with OFET device performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.104-104
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• 2010

With the advent of nano-particle fillers in insulating materials, the insulating materials of superior quality have come to fore. In the recent past, nanocomposite LDPE/XLPE (Low Density Polyethylene/Cross Linked Polyethylene) power cable dielectrics have been synthesized. A preliminary evaluation of these new class of materials seem to show that, addition of small amounts of sub-micron inorganic fillers improved the dielectric properties of the composite, in particular, the volume resistivity, and the DC breakdown strength. The thermal behaviour, for example, the stability of composites against decomposition and ensuing electrical failure, do not seem to have been addressed. In a conventional XLPE insulated cable, the average thermal breakdown strength and maximum temperature at the onset of breakdown were seen to be markedly lower than the corresponding intrinsic breakdown strength and decomposition temperature. In this page, analysis of DC Breakdown of nano-composite insulating material for HVDC Cable is introduced.

• BMB Reports
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• v.29 no.4
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• pp.372-379
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• 1996

Components I and II (CI&II) are major phosphoproteins in the frog rod outer segments (ROS) of retina, whose phosphorylation is light- and cyclic nucleotide-dependent. Although it was reported that CI & II could be chemically cross-linked to ${\beta}{\gamma}-subunit$ of transducin (${\beta}{\gamma}_t$), it was not clear whether CI&II physically interact with ${\beta}{\gamma}_t$, under native conditions. CI&II extracted by hypotonic washing fo ROS membranes showed an overlapped migration with ${\beta}{\gamma}_t$, in sucrose density gradient centrifugation. The elution profile of CI&II in the peripheral membrane fractions from gel filtration chromatography also overlapped that of ${\beta}{\gamma}_t$. These hydrodynamic parameters indicate that the native molecular state of CI&II in the peripheral membrane fraction appears to be within a complex, most likely with ${\beta}{\gamma}_t$. CI&II coeluted with ${\beta}{\gamma}_t$, showed no phosphorylation by endogenous kinase which phosphorylates a serine of CI&II in other fractions. The purified CI&II were not able to inhibit trypsin-activated cGMP-phosphodiesterase, and CI&II were not recognized by a monoclonal antibody against the ${\gamma}-subunit$ of transducin, indicating that CI&II are not y-subunit of PDE or transducin. Thus, it is likely that native CI&II, which undergo a light-dependent phosphorylation/dephosphorylation cycle, can associate with ${\beta}{\gamma}$, in frog photoreceptor membranes, and the complex formation has an inhibitory effect on the endogenous phosphorylation of CI&II.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.8
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• pp.701-705
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• 2007

The incorporation of N in a-C film is able to improve the friction coefficient and the adhesion to various substrates. In this study, a-C:N films were deposited on Si and steel substrates by closed-field unbalanced magnetron (CFUBM) sputtering system in $Ar/N_2$ plasma. The lubricant characteristics was investigated for a-C:N deposited with total working pressure from 4 to 7 mTorr. We obtained high hardness up to 24GPa, friction coefficient lower than 0.1 and the smooth surface of having the extremely low roughness (0.16 nm). The physcial properties of a-C:N thin film are related to the increase of cross-linked $sp^2$ bonding clusters in the film. However, the decrease of hardness, elastic modulus and the increase of surface roughness, friction coefficient with the increase of $N_2$ partial pressrue might be due to the effect of energetic ions as a result of the increase of ion bombardment with the increase of ion density in the plasma.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.01a
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• pp.41-43
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• 2012

Today many people are greatly interested in the environment. Especially increasing affluent of food causes a great amount of food waste. To handle this effectively, we now have a lot of problems of disposing garbage all over the world. In Korea, in order to reduce this garbage, we should use a standard plastic garbage bag in which we have to throw away our garbage. So it has an effect on significantly reducing the waste amount every year. Now, there are a lot of cases that residents again use a standard plastic garbage bag. The purpose of this study is to propose algorithm preventing the re-cycling of a standard plastic garbage bag.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.693-697
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• 2016

In this study, we fabricated the catalysts for enzymatic biofuel cell anode with carbon nanotube (CNT), glucose oxidase (GOx) and various molecular weights branched poly(ethyleneimine)(bPEI) and terephthalaldehyde (TPA) as cross-linker. In case of GOx/bPEI/CNT using only physical entrapments for immobilization, the molecular weights of bPEI didn't affect to electrochemical performances and long term stability. but that of the catalysts cross linked via TPA (TPA[GOx/bPEI/CNT]) improved and the mass transfer of glucose to FAD was interrupted as increasing of the bPEI's molecular weights. Furthermore, it was confirmed that the optimum molecular weight of PEI for TPA [GOx/bPEI/CNT]) structure is 750k that showed marvelous high performance (maximum power density of $0.995mW{\cdot}cm^{-2}$).

• Journal of the Korean Vacuum Society
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• v.6 no.3
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• pp.213-219
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• 1997

The plasma polymerized styrene films were prepared by using an inter-electrode capacitively coupled gas-flow-type reactor, and the effects of plasma polymerization condition on the molecular weight distribution were investigated by Fourier Transform Infrared (FT-IR), Pyrolysis Gas Chromatography(PyGC), Differential Scanning Calorimetry(DSC) and Gel Permeation Chromatography(GPC). From the above results, the very cross-linked films different from chemical characteristics of the starting monomer were taken out, and it is realized that the molecular structure, cross linking density, and molecular weight distribution could be controlled by changing the parameters such as deposition pressure, deposition power and gas flow rate. Accordingly, it is suggested that plasma polymerization method performed by inter-electrode capacitively coupled gas-flow-type reactor has good characteristics for manufacturing the functional organic thin films which can be applied in sensors, opto-electric device, photo-resist by changing the polymerization parameters.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.611-618
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• 2007

We demonstrate the sol-gel coating technique of colloidal clusters for producing hollow micro-particles with complex morphologies. Cross-linked amidine polystyrene (PS) microspheres were synthesized by emulsifier-free emulsion copolymerization of styrene and divinylbenzene. The amidine PS particles were self-organized inside toluene-in-water emulsion droplets to produce large quantities of colloidally stable clusters. These clusters were coated with thin silica shell by sol-gel reaction of tetraethylorthosilicate (TEOS) and ammonia, and the organic polystyrene cores were removed by calcination at high temperature to generate nonspherical hollow micro-particles with complex morphologies. This process can be used to prepare hollow particles with shapes such as doublets, tetrahedra, icosahedra, and others.

• CELLMED
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• v.13 no.14
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• pp.15.1-15.15
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• 2023

Background and objective: A new formular CPC22 consists of Cynanchum wilfordii root, Pueraria thomsonii flower, and Citrus unshiu peel and has been developed to improve the postmenopausal symptoms. The research intended to evaluate whether CPC22 would regulate bone loss, hot flashes, and dysregulated lipid metabolism in ovariectomized (OVX) postmenopausal mice. Method: The OVX mice were orally administered with CPC22 daily for 7 weeks. Results: CPC22 regulated OVX-induced bon loss by enhancing serum osteoprotegerin, alkaline phosphatase, and osteocalcin levels and diminishing serum receptor-activator of the NF-κB ligand (RANKL), collagen type 1 cross-linked N-telopeptide, and tartrate-resistant acid phosphatase levels. As a result of CPC22 treatment, notable decreases in tail skin temperature and rectal temperature were observed, along with diminishment in hypothalamic RANKL and monoamine oxidase A levels and enhancement in hypothalamic serotonin (5-HT), norepinephrine, dopamine, 5-HT2A, and estrogen receptor-β levels. CPC22 enhanced levels of serum estrogen and diminished levels of serum follicle-stimulating hormone and luteinizing hormone. CPC22 regulated levels of serum lipid metabolites, including total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Furthermore, CPC22 diminished levels of serum blood urea nitrogen, creatine kinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase and restored vaginal dryness without affecting uterus atrophy index and vagina weights. Conclusion: Therefore, these results indicated that CPC22 improves OVX-induced bone loss, hot flashes, and dysregulated lipid metabolism by compensating for estrogen deficiency without side effects, suggesting that CPC22 may be used for the prevention and treatment of post menopause.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.207-212
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• 1990

Enzyme-linked immunosorbent assay(ELISA) of paragonimiasis iloktsuenensis rat sera was performed using crude antigens of Paragonimus iloktsuenensis(PIA), P. westermani (PWA) and Clonorchis sinensis(CSA). Three crude antigens(PIA, PWA, CSA) were prepared to saline homogenated supernatants of whole adult worms. Infected rat sera were obtained biweekly from the albino rats fed 50∼.80 metacercariae of P. iloktsuenensis through gastric catheter. Experimental groups were divided into 4 groups: GI(controls), GII, GIII and GIV according to 1∼7 worms as GII, 10∼19 worms as GIII and 22∼40 worms as GIV, respectively, In ELISA, the mean OD values of each group for the homologous antigen(PIA) were increased significantly compared to the control sera at the 4th week of infection. With the progress of duration of infection, the mean OD values of infected sera of GII & GIV continuously increased up to the 12th week(last week), but in GIII the mean OD value increased until the loth week. No significance was noted among the infection dose groups (GII, GIII and GIV), after the 6th week of infection. Also, the OD values of all infected rats did not show any Proportional relytionships to the number of worms recovered. In brief, the antibody productivity of individual rats were strongly different. The rat sera infected with p. iloktsuenensis cross-reacted with those infected with P. westermani or C. sinensis, as identified by OD values.