• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.351-351
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• 2002

새로운 LCST 형 블록 공중합체를 설계하기 위하여 LCST 블렌드 계를 선정하고, 이로부터 대응되는 블록 공중합체를 고안하였다 고안된 블록 공중합체의 분자 변수와 자기 집합에 의한 나노 미세 상 발현 거동과의 관계를 Cho의 압축성 random-phase approximation (RPA) 이론을 이용하여 구하였다. 본 연구의 대상 물질은 polystyrene (PS)과 poly(vinyl methyl ether) (PVME), PS 와 Poly(cyclo hexyl methacrylate) (PCHMA)의 블록 공중합체이다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.223-226
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• 2001

비닐에테르류의 비닐단량체는 ZnI$_2$ 존재하에서 HI와 같은 프로톤 산에 의해 양이온 리빙중합이 가능함이 보고된 바 있는데 이 때 프로톤산은 비닐에테르 단량체와 반응하여 adduct를 생성하고, ZnI$_2$는 adduct의 양이온중합 활성화제로 작용하는 것으로 알려져 있다. (중략)

• Bulletin of the Korean Chemical Society
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• v.7 no.3
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• pp.210-213
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• 1986

1,1-Dicyano-2-ethoxycyclobutane (1a) was prepared by [2 + 2] cycloaddition reaction of vinylidene cyanide with ethyl vinyl ether. 1,1-Dicyano-2-phenylcyclobutane (1b) was prepared by the reactions involving the reduction of cinnamyl alcohol, chlorination, cyanomethylation, bromination, and ring-closure reaction. Compound 1a was ring-opening polymerized with NaCN or n-butyllithium to give a low molecular weight polymer. The compound 1b however, failed to polymerize by either anionic or radical catalysts.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.480-484
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• 2012

Concrete, the mixture of cement, sand, gravel and water, is a suspension substance extensively used to construct building materials. When a concrete mortar is applied to the underwater construction, the rheology of concrete is of great importance to its flow performance, placement, anti-washout and consolidation. In this research, the anti-washout and rheological properties of concrete have been investigated with concrete admixtures prepared by adding anionic surfactants, cationic surfactants, and polymeric thickeners. The concrete mortar formulated by pseudo-polymeric systems with the electrostatic association of anionic and cationic surfactants, showed high viscosities and suitable anti-washout properties, but poor pumpabilities. The addition of poly methyl vinyl ether to the mixed surfactant system exhibits synergistic effects by improving the concrete mortar properties of the concrete mortar such as fluidity, visco-elastic property, self-leveling, and anti-washout.

• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.83-89
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• 1999

The electrical properties due to mixture ratio of linear low density polyethylene(LLDPE) and ethylene vinyl acetate(EVA) films are studied. An experimental specimen is selected as LLDPE/EVA of thickness 200${\mu}{\textrm}{m}$ produced by mixture ratio of 50 : 50, 60 : 40, 70 : 30 and 80 : 2 wt%. In temperature range from $25^{\circ}C$ to 12$0^{\circ}C$, the measurement of volume resistivity using a highmegohm meter is performed within 10 minutes since each voltage of DC 100 V, 250 V, 500 V and 1000 V is applied, according to the step voltage method. From FT-IR spectrum for an analysis of physical properties, it can be confirmed that LLDPE blended with EVA shows an absence of carbonyl groups(1735 $cm^{-1}$, C=0) and ether groups(1242 $cm^{-1}$, C-O). The peak of LLDPE and EVA made of mixture ratio of 70 : 30 at 2$\theta$ =21.4$^{\circ}$ in the results of XRD is higher than the others. In the experiment for volume resistivity characteristics in order to investigate the electrical properties of specimen, it is confirmed that volume resistivity is decreased with the increase of the molecular motion and temperature.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.451-454
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• 1997

An attempt was made in this study to analyze volatile flavor components of fresh and odorless garlic (Allium sativum L.), Essential oils in fresh garlic and odorless garlic were isolated by a simultaneous steam distillation and extraction(SDE) method using n-pentane/diethy ether as solvent. A total of 21 and 22 components were identified by GC/MS from the essential oils of fresh garlic and odorless garlic, respectively. Diallyl trisulfide, diallyl disulfide and methyl allyl disulfide were found to be major volatile flavor components in fresh garlic and odorless garlic. By the preparation of ordorless garlic, 77.5% of diallyl trisulfide, 15.0% of diallyl disulfde, 72% of methyl allyl disulfide, and 78.4% of allyl thiol components in fresh garlic were lost. Eleven compounds including 2-vinyl-4H-1,3-dithiin, eugenol and 2-methoxy-4-vinyl-phenol were identified in odorless garlic, but not m fresh garlic.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.123-127
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• 1993

New lipophilic Crown-4 compounds of 16-membered rings containing furan (neutral carrier,I), tetrahydrofuran (neutral carrier,II) and lithium complex of the latter (neutral carrier,III) have been synthesized and tested as the active sensors for lithium ion in poly(vinyl chloride) (PVC) membrane electrode, in the presence and absence of an anion excluder, tetrakis(4-chloro-phenyl)borate (KTClPB), 2-nitrophenyl phenyl ether (NPPE), tris(2-ethylhexyl)phosphate (TEHP), o-nitrophenyl octyl ether (NPOE), dioctyl adipate (DOA), bis(2-ethylhexyl)adipate (BEHA), di-n-octylphenyl phosphonate (DOPP) were used as plasticizing solvent mediators. The electrode response function had a nearly Nernstian slope of 54-61 mV per decade (25$^{\circ}$C) within the concentration range of $10^{-1}-10^{-4}$ M LiCl and the detection limits for all electrodes were ca. $5{\times}10^{-4}$ M. The response time of the electrode was faster at the higher lithium concentration and the response of the electrode was stable for longer than 6 months. The sensor membranes exhibit improved response times and increased lifetimes as compared to the system described earlier.

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.167-173
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• 2010

Repeated oral administration of hydrochlorothiazide, a loop diuretic, due to transient high blood levels, may cause adverse effects such as gastric disturbance, nausea, high blood sugar, and hyper lipidemia. Transdermal administration could avoid some of these systemic side effects and gastric disorders. We have developed a matrix using ethylene-vinyl acetate (EVA), a heat-processible and flexible material, for transdermal delivery of hydrochlorothiazide. Drug solubility was highest at 40% PEG-400 volume fraction. Drug release increased as concentration increased with a linear relationship between the release rate and the square root of loading dose. Increasing temperature increased drug release from the EVA matrix. The activation energy, measured from the slope of log P versus 1000/T, was 11.9 kcal/mol for a 2.5% loading dose from EVA matrix. Diethyl phthalate had the highest plasticizing effects on the release of hydrochlorothiazide. To increase the skin permeation of hydrochlorothiazide from the EVA matrix, enhancers such as the saturated fatty acids, the unsaturated fatty acids, and the non-ionic surfactants were added to the EVA matrix, and skin permeation was evaluated using a modified Keshary-Chien diffusion cell fitted with intact excised rat skin. Polyoxyethylene 23-lauryl ether showed the highest enhancing effects. In conclusion, transdermal delivery of hydrochlorothiazide could be improved from an EVA matrix containing plasticizer and permeation enhancer.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.773-778
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• 1993

Poly(vinyl chloride)(PVC) membrane electrodes based on the lipophilic neutral carrier, dibenzo-18-crown-6(DB18C6) and benzo-15-crown-5 (B15C5) as the active sensors for Tl$^+$ ion have been prepared and tested in different content of the potassium tetrakis(4-chlorophenyl)borate (KTClPB) as lipophilic salt. Dioctyl adipate (DOA), 2-nitrophenyl phenyl ether (NPPE) and o-nitrophenyl actyl ether (NPOE) were used as plasticizing solvent mediators. Electrodes exhibited good linear responses of 40∼55 mV decade$^{-1}$ for Tl$^+$ ion within the concentration ranges 10$^{-1}$∼10$^{-5}$M TlNO$_3$. Selectivity coefficients of interfering ions (alkali metal, alkaline earth metal and some transition metal ions) for Tl$^+$-ISE were determined by separate solution method and were sufficiently small for most of them. These crown ether type ion-selective electrodes are suitable for use with aqueous solution at pH > 3.