• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.36-46
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• 1998

The aim of this study was to develop the noise and vibration damping wood-based composites by using viscoelastic polymer materials. Polyvinylchloride(PVC) was plasticized with 20-140 phr bis(2-ethylhexyl) phthalate(DOP) and the dynamic tensile mechanical properties were measured at 110Hz and approximate temperature range -100 to 150$^{\circ}$ using a Rheovibron Instrument. The PVC/DOP blends were shown to be compatible in all proportions, and both T(E”$_{max}$) and T(tan${\delta}_{max}$) shifted to the lower temperature side as the DOP content increased. The vibration damping properties of wood/polymer composites were measured using the Rheovibron instrument in a bending mode. The composite damping factor(tan ${\delta}_{c}$) of wood /PVC-DOP/wood sandwich structure correlated with the loss factor and that of the coated structure correlated with the loss modulus(E”) of the polymer layer. In addition, the sandwich structure was found to be more effective in damping than the coated structure. The logarithmic decrement (${\Delta}$c) curve of a sandwich structure, which was determined by the free-free flexural vibration method was similar in shape to the tan ${\delta}_{c}$ curve.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1995.04a
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• pp.91.2-91
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• 1995

레이저를 이용한 구강 및 인후두 수술시 endotracheal tubes의 손상은 치명적이라 아니 할 수 없다. 이에 저자들은 여러 가지 endotracheal tube를 실험 재료로 사용하여 보다 안전한 레이저 수술을 위해서 적절한 endotracheal tube를 찾기 위해 본 실험을 시행하였다. 실험에 사용된 tube는 총 5가지 - $Bivona^{TM}$, Xomed Laser Shield $II^{TM}$, Mallinckrodt Laser-$Flex^{TM}$, Rusch tube wrapped with aluminium foil tape(Rusch tube), Polyvinylchloride tube wrapped with aluminium foil tape(PVC tube) - 가 사용되었다. 사용된 레이저는 KTP/532 와 $CO_2$ laser 이며 모든 실험에서 tube를 $FiO_2$ 95%-98% 상태에서 조사하여 각각 5회씩 실시하였다. tube에 이상이 없거나 발화가 되지 않는 한 90초 동안 시행하였다. 실험 결과, KTP/532 조사시 $Bivona^{TM}$, Mallinckrodt 와 PVC tube는 심한 손상을 받거나 발화하였으며 Xomed 와 Rusch tube는 안정된 상태를 유지하였고 $CO_2$ Laser 조사시는 KTP/532 조사시와 유사한 결과를 얻었다. 한편 혈액을 endotracheal tube에 도포한 상황에서는 모든 tube가 더 심한 손상을 보이는 바 KTP/532 조사시 Xomed는 상당히 안정된 상태를 유지하였고 나머지 tube는 심한 손상 또는 발화를 보이고 $CO_2$ Laser 조사시 $Bivona^{TM}$ 와 Mallinckrodt는 발화하였고 Rusch tube는 표면이 녹았으며 Xomed와 PVC tube도 1례에서 발화하였다. 향후 이비인후과 영역에서의 레이저 수술이 증가함을 예상할 때 좀 더 레이저에 대하여 안정적이고 경제적인 endotracheal tube의 개발이 필요할 것으로 사료된다.

• The Journal of Korea Robotics Society
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• v.16 no.1
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• pp.41-48
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• 2021

In this paper, we review papers which report to the all solid-state electroactive polymer-based tunable lens. Since electroactive polymer-based tunable lenses change their focal length by responding to electric stimuli, it can be minimized the size and weight of optical modules. Thus, it has been received attention in the robot, mobile device and display industry. The all solid-state electroactive polymer-based tunable lenses can be classified into two categories depending on the classification of materials: ionic electroactive polymer-based lenses and non-ionic electroactive polymer-based lenses. Most of the ionic electroactive polymer-based tunable lenses are fabricated with ionic polymer-metal composite. So, the ionic electroactive polymer-based tunable lenses can be operated under low electric voltage. But small force, slow recovery time and environmental limitation for operation has been pointed to the disadvantage of the lenses. The non-ionic electroactive polymer-based tunable lenses are classified again into two categories: dielectric polymer-based tunable lenses and polyvinylchloride gel-based tunable lenses. The advantage of the dielectric polymer-based tunable lenses is fast response to electric stimuli. But the essential flexible electrodes degrade performance of the lens. Polyvinylchloride gel-based tunable lens has reported impressive performance without flexible electrodes.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.296-303
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• 2005

The co-pyrolysis characteristics of polyvinylchloride (PVC) and acrylonitrile butadiene styrene (ABS) mixtures with various mixing ratios and effect of addition of CaO and $Cu_2O$ have been studied using thermogravimetry (TG) and gas chromatograph-mass spectrometry (GC-MS). In an isothermal decomposition conducted at $500^{\circ}C$, the yields of styrene monomers and aromatic compounds increased as the mixing ratio of ABS increased, and the yield of BTX compounds reached its maximum (16.14%) when the mixing ratios of PVC and ABS was 4:1. In an isothermal decomposition added with metal oxides, the maximum yield of liquid product was 73% when CaO [CaO/(PVC+ABS)=0.4] was added and it was 70% when $Cu_2O$ [$Cu_2O$/(PVC+ABS)=0.4] was added, respectively, where HCl contained in the gaseous product was completely removed when added with CaO [CaO/(PVC+ABS)=0.5] and $Cu_2O$ [$Cu_2O$/(PVC+ABS)=1.0]. Therefore, to obtain the highest yield of liquid product it appears to be the reaction condition: the reaction temperature of $500^{\circ}C$ and mixing ratios of CaO and $Cu_2O$ are 0.5 and 1.0, respectively.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.151-160
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• 1990

In order to develop a controlled-release oral drug delivery system (DDS) which sustains the plasma acetaminophen (AAP) concentration for a certain period of time, microporous membrane-coated tablets were prepared and evaluated in vitro. Firstly, highly water-soluble core tablet of AAP were prepared with various formulations by wet granulation and compression technique. Then the core tablets were coated with polyvinychloride (PVC) in which micronized sucrose particles were dispersed. Effect of formula compositions of core tablets and coating suspensions on the pharmaceutical characteristics such as drug release kinetics and membrane stability of the coated tablets was investigated in vitro. AAP was released from the coated tablets as a zero-order rate in a pH-independent manner. This independency of AAP release to pH change from 1.2 to 7.2 is favorable for the controlled oral drug delivery, since it will produce a constant drug release in the stomach and intestine regardless of the pH change in the GI tract. Drug release could be extended upto 10 h according to the coating condition. The release rate could be controlled by changing the formula compositions of the core tablets and coating suspensions, coat weight per each tablet, and especially PVC/sucrose ratio and particle size of the sucrose in the coating suspension. The coated tablets prepared in this study had a fairly good pharmaceutical characteristics in vitro, however, overall evaluation of the coated tablet should await in vivo absorption study in man.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1998.10a
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• pp.99-102
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• 1998

우리나라 윈예생산 시설의 피복에 사용되는 피복자재는 값이 싸고 설치가 쉬우며 비교적 광투과율이 높고 시설에 피복할 경우 긴밀도가 뛰어나 보온력이 우수한 플라스틱 필름이 99 % 이상을 차지하고 있다. 최근에 플라스틱 필름의 종류는 다양하게 발전하여 소재는 PE(polyethylene), EVA(ethylene vinylacetate), PVC(polyvinylchloride), 등의 연질필름과 PET(poly ethylene terephthalate) 그리고 ETFE(ethylene tetrafluoride ethylene) 등의 반경질핌름으로 되어 있다. (중략)

• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.209-213
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• 2012

Purpose: This study was performed to develop a simple, disposable thin-film optical nitrate sensor. Methods: The sensor was fabricated by applying a nitrate-selective polymer membrane on the surface of a thin polyester film. The membrane was composed of polyvinylchloride (PVC), plasticizer, fluorescent dye, and nitrate-selective ionophore. Fluorescence intensity of the sensor increased on contact with a nitrate solution. The fluorescence response of the optical nitrate sensor was measured with a commercial fluorospectrometer. Results: The optical sensor exhibited linear response over four concentration decades. Conclusions: Nitrate ion concentrations in plant nutrient solutions can be determined by direct optical measurements without any conditioning before measurements.

• Elastomers and Composites
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• v.57 no.4
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• pp.222-230
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• 2022

In this study, a low-heat additive with a crosslink structure was dispersed in asphalt to simultaneously lower the production temperature of, and to modify the asphalt binder. This low-heat additive was prepared by different feeding ratios of styrene-butadiene-styrene (SBS) and polyvinylchloride (PVC) as polymer modifiers, and ZnO as a crosslinking agent. In order to confirm the crosslinking density and compatibility of the crosslink structured low-heat additive with asphalt, surface free energy, swelling ratio, differential scanning calorimetry (DSC), and scanning electron microscope (SEM) parameters were carefully investigated to examine this relationship, and the role of the crosslink structured low-heat additive. In addition, by measuring the penetration and softening point of the asphalt binder, it was confirmed that it corresponds to PG 64-22. With increasing ZnO in the crosslink structured low-heat additive, the swelling ratio decreased, leading to an increase in crosslinking density. The crosslink structured low-heat additive and the asphalt binder were found to be compatible with each other by DSC and SEM analysis.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.581-588
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• 2018

In this article, electrochemical investigation of the transfer reaction of ionizable cefotiam (CTM), an antibiotic molecule across a polarized water/1,2-dichloroethane (water/1,2-DCE) interface was studied. Ion partition diagram providing the preferred charged form of CTM in either water or 1,2-DCE phase was established via the voltammetric evaluation of the transfer process of differently charged CTM species depending upon the pH variation of aqueous solutions. Thermodynamic information including the formal transfer potential and formal Gibbs transfer energy values in addition to important pharmacokinetics including partition coefficients of ionizable CTM were also evaluated. In particular, the current associated with the transfer of CTM present at pH 3.0 aqueous solution proportionally increased with respect to the CTM concentration which was further used for developing CTM sensitive ion sensor. In order to improve the portability and convenient usage, a single microhole interface fabricated in a supportive polyethylene terephthalate film was used of which hole was filled with a polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel replacing 1,2-DCE, a toxic organic solvent. A dynamic range of $1-10{\mu}M$ CTM was obtained.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.506-512
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• 2017

The transfer reaction characteristics of tetracycline (TC) across a polarized water/1,2-dichloroethane (1,2-DCE) interface was studied via controlling both pH and ionic strength of the aqueous phase in conjunction with cyclic and differential pulse voltammetries. Formal transfer potential values of differently charged TC ionic species at the water/1,2-DCE interface were measured as a function of pH values of the aqueous solution, which led to establishing an ionic partition diagram for TC. As a result, we could identify which TC ionic species are more dominant in the aqueous or organic phase. Thermodynamic properties including the formal transfer potential, partition coefficient and Gibbs transfer energy of TC ionic species at the water/1,2-DCE interface were also estimated. In order to construct an electrochemical sensor for TC, a single microhole supported water/polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel interface was fabricated. A well-defined voltammetric response associated with the TC ion transfer process was achieved at pH 4.0 similar to that of using the water/1,2-DCE interface. Also the measured current increased proportionally with respect to the TC concentration. A $5{\mu}M$ of TC in pH 4.0 buffer solution with a dynamic range from $5{\mu}M$ to $30{\mu}M$ TC concentration could be analyzed when using differential pulse stripping voltammetry.