• Polymer(Korea)
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• v.33 no.1
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• pp.45-51
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• 2009

Water soluble adhesive was polymerized from butyl acrylate (BA), methyl methacrylate (MMA) and one of various functional monomers such as acrylic acid (AA), 2-hydroxylethyl methacrylate (2-HEMA), glycidyl methacrylic acid (GMA) and acrylamide (AAm). The amount of the functional monomers was 1$\sim$5 wt%/monomer. In order to improve the adhesive power, a substrate was treated using atmospheric flat plasma method. The adhesive power was improved by the addition of the functional monomers with an order of AA> 2-HEMA> GMA> AAm. The holding power of the adhesives, which is related with the thermal properties of the adhesives, increased with the amount of the functional monomers. The effectiveness in improving the holding power has an order of AA > AAm > GMA > 2-HEMA. By treating a substrate with atmospheric flat plasma method, the adhesives containing each of AA, 2-HEMA, GMA and AAm showed the increases of the final adhesion strength by 9.1, 9.4, 9.4, and 1.8%, respectively. In conclusion, the mechanical properties such as adhesive power and holding power could be controlled by introducing.

• Journal of fish pathology
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• v.7 no.1
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• pp.63-70
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• 1994

Nitric oxide(NO) has recently been shown to play an important role on central nervous system(CNS) function in mammals. It is synthesized from L-arginine by the enzyme NO synthase. In this study, we examined this enzyme's existence in CNS of rainbow trout(Oncorhynchus mykiss) and described the forms of microglia. astrocytes. and oligodendrocytes. Two forms of microglia are distributed in CNS. one resembling their mammalian counterpart(large microglia : LM). and the other comprising small microglia(SM) with very little cytoplasm. CNS contained astrocytes of a distinct type which form reticular network, but lack connections to capillaries. The oligodendrocyte was generally a much denser cell than the astrocyte. We have detected NOS($1.04{\pm}0.12\;pg/min/mg$) from rainbow trout CNS. It could be inhibited reversibly or irreversibly by $N^{G}MMA$ and EGTA. These result suggest that the formation of NO from L-arginine in CNS is calcium-dependent and a pathway of early evolutionary orgin.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1636-1638
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• 1996

MMA-Styrene-Tetramethyltin(MST) thin films were fabricated by plasma polymerization method, and their electrical properties were confirmed by IR and GPC. The electrical conductivity increased with increasing temperature, and the adsorption current hardly appeared. The high-field electrical conduction mechanism is the electronic one such as schottky, and the activation energy is about 1.1 eV.

• Elastomers and Composites
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• v.28 no.3
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• pp.191-197
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• 1993

The graft copolymerization of methyl methacrylate(MMA) onto natural rubber latex(NRL) initiated by t-butyl hydroperoxide(t-BHPO) was investigated in aquous medium. The grafting percentage, grafting efficiency and total conversion were observed in various reaction conditions such as monomer, initiator and emulsifier concentration, reaction temperature, reaction time and agitation speed. The optimum conditions for the graft copolymerization onto natural rubber latex were as follows ; At given monomer concentration of $3{\times}10^{-2}mole/l$, the maximum grafting percentage was appeared in the case of grading in initiator concentration of $4{\times}10^{-2}mo1e/l$ and emulsifier concentration of 0.2wt.% at $40^{\circ}C$ for 5hrs.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.18-24
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• 2002

n this paper, we have fabricated pseudomorphic high electron mobility transistors (PHEMT) with a 0.2 ${\mu}{\textrm}{m}$ wide-head T-shaped gate using electron beam lithography by a dose split method. To make the T-shape gate with gate length of 0.2 ${\mu}{\textrm}{m}$ and gate head size of 1.3 ${\mu}{\textrm}{m}$ we have used triple layer resist structure of PMMA/P(MMA-MAA)/PMMA. The DC characteristics of PHEMT, which has 0.2 ${\mu}{\textrm}{m}$ of gate length, 80 ${\mu}{\textrm}{m}$ of unit gate width and 4 gate fingers, are drain current density of 323 ㎃/mm and maximum transconductance 232 mS/mm at $V_{gs}$ = -1.2V and $V_{ds}$ = 3V. The RF characteristics of the same device are 2.91㏈ of S21 gain and 11.42㏈ of MAG at 40GHz. The current gain cut-off frequency is 63GHz and maximum oscillation frequency is 150GHz, respectively.ively.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.93-98
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• 2013

In this paper, We have fabricated PMMA thin films by plasma polymerization method for organic thin film transistor's insulator layer. For improving the characteristics of organic transistor, we tested transistor's mobility and output values with organic transistor's electrode structures. As a results, the mobility of top contact was $8{\times}10^{-3}[cm^2V^{-1}s^{-1}]$, that of bottom contact was $2{\times}10^{-4}[cm^2V^{-1}s^{-1}]$. Also, off current of bottom contact was increased. Therefore, we recommend the top contact electrode structure of organic transistor.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.445-451
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• 2010

To prepare very stable acrylic type emulsion having a visible ray absorption property, in-situ preparation technique of $Cu_xS$ nanoparticle was adopted. Firstly, the acylic emulsions of methyl methacrylate(MMA), butyl acrylate(BA), and acrylonitrile(AN) were synthesized by pre-emulsion polymerization at $60^{\circ}C$ in the presence of anionic surfactant. Secondly, $Cu_xS$ nanocomposited emulsions were directly prepared in the prepolymerized acrylic emulsion with $CuSO_4$ at $50^{\circ}C$. The presnce of $Cu_xS$ nanoparticle in emulsion was confirmed by SEM and EDS. The final $Cu_xS$ nanocomposited emulsion showed an olive-green colour and good emulsion stability up to 1 month. In addition the PET films coated with our $Cu_xS$ nanocomposited emulsion absorbed effectively the visible ray.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.493-498
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• 2006

In this paper, we propose a blood pressure measurement method using ANFIS. Usually, the maximum and minimum blood pressures are calculated by Maximum Amplitude Algorithm(MAA) method. However, the MAA method has some drawbacks to measure exact blood pressure since it uses a fixed ratio to set the measuring points for everyone without considering individual's special conditions. To solve this problem, the pressures measured by the MMA are trained by ANFIS having self-learning ability. From various experiments, we confirm that the proposed method shows better performance than conventional method.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.7
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• pp.279-286
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• 2002

Linear and nonlinear complex permittivities were measured for copolymers of vinylidene cyanide(VDCN) with vinyl acetate(VAc), vinyl propionate(VPr), vinyl bezoate(VBz), styrene(St) and methyl methacrylate(MMA). Experimental results are well fitted by the function (equation omitted) except at low frequency where dc conduction dominates. The analysis of dielectric relaxation mechanism by combined knowledge about linear and nonlinear dielectric permittivities and dipoles give us informations about electrical and thermal motions in these copolymers. According to the analysis it could be found that the variation for temperature of the dielectric relaxation strength in these copolymers is related to the interaction between dipoles and the nonlinear dielectric effect factor R$_{s}$ is proportional to square of the dipolar correlation factor R$_{p}$././.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.382-383
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• 2007

PMMA plate with nano-sized pattern was synthesized on anodized aluminum oxide template by bluk polymerization method. Anodized aluminum oxide was used as a template to synthesize the PMMA plate with nano-sized pattern. The polymerization of MMA was performed at $75-79^{\circ}C$. It is verified from SPM results that the nano-sized pattern on synthesized PMMA plate was well transferred from that of anodized aluminum oxide template.