• Elastomers and Composites
• /
• 제37권1호
• /
• pp.7-13
• /
• 2002

본 연구에서는 PVC 수지에 첨가되는 고가의 충격보강제(MBS) 대신에 Phosphate, CaO등을 함유하고 있는 산업부산물인 부생석고(남해화학), Pb계의 복합안정제, $CaCO_3$ 등을 함유한 PVC 복합체의 역학적 성질을 혼합 성분비에 따라 측정하였다. 그 결과 석고의 양이 8.46wt%일때 기계적 물성이 향상되었다. 이는 PVC와 phosphate, CaO 등을 포함한 석고와의 상용성에 따른 결과로 생각된다. 열중량 분석(TGA)결과 약 $275^{\circ}C$에서 열분해를 시작하였고, 열분해 후 잔존량은 첨가되는 석고의 양에 비례했으며, 시차주사 열량계(DSC) 측정결과 $T_m,\;T_g$는 석고의 양이 8.46wt%일 때 각각 가장 높은 값과 낮은 값을 보여 열안정성이 증가하였다. 역학적 물성과 열안정성 측정 결과를 비교하면 석고의 양이 8.46wt%일 때 역학적 물성과 열 안정성이 모두 향상되었음을 알 수 있다. X-ray 회절 분석결과에서 석고와 PVC가 블렌드되어 있음을 확인하였다.

• The Korean Journal of Medicine
• /
• 제99권1호
• /
• pp.17-24
• /
• 2024

Premature atrial complex (PAC) and premature ventricular complex (PVC) are the most common arrhythmias. Most of them are benign, whereas some could be an initial sign of any underlying significant heart disease. Evaluation of daily burden and the presence of any association with underlying medical conditions are essential for proper assessment. Recently, newly developed electrocardiogram smart devices are widely available to document arrhythmias and identify correlations with symptoms. Management is required if the daily burden is high, patients are highly symptomatic, or significant structural heart disease is present. Antiarrhythmic drugs (AADs) are the first-line treatment, but if arrhythmias are drug-refractory or the patients are intolerable to AADs, catheter ablation is considered a good alternative in selected cases. In this paper, the proper diagnosis and management for PAC and PVC will be comprehensively reviewed.

• 약학회지
• /
• 제43권3호
• /
• pp.289-293
• /
• 1999

Many poly (vinyl chloride : PVC) membrane electrodes were investigated for the determination of basic drugs, chlorpromazine, amitriptyline, nortriptyline, etc. These electrodes are based on the use of the ion-association complexes of the basic drugs with eriochrome cyanine R, chromoxane cyanine, chrome azurol S and picric acid as ion-exchange sites in a plasticized PVC matrix. All ion-exchangers except picrate complex were not proper for use, because those complexes in plasticized membrane were excluded into aqueous working solution. These drug electrodes show excellent Nernstian responses in the concentration ranges $10^{-2}~10^{-6}$ mol $dm^{-3}$. Their selectivity with respect to each other, as well as their work-able pH range have been investigated. The major advantages of the proposed methods are their simplicity and speed.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1993년도 추계 총회 및 학술발표회
• /
• pp.46-51
• /
• 1993

Poly(vinyl chloride) was modified by reacting with sodium N-methyldithiocarbamate or N-methyl-N-carboxymethyldithiocarbamate to obtain crosslinked dithiocarbamated PVC(PMD, PSDC). In addition PSDC were substituted with metal ions of $Ma^+, Li^+$ and $Cs^+$. PLMD and PSDC were reacted with copper ions in alcohol or aqueous solution to produce chelate complexes of dithiocarbanated PVC, respectively(PMD-$Cu^{2+}$, PSDC-$Cu^{2+}$). PSDC was irradiated by ultraviolet light to enhance crosslinking(PSDC-UV).

• Bulletin of the Korean Chemical Society
• /
• 제24권1호
• /
• pp.37-44
• /
• 2003

We examined the effect of polyether-type nonionic surfactants (Brij 35, Triton X-100, Tween 20 and Tween 80) on the potentiometric properties of sodium-, potassium- and calcium-selective membranes which are prepared with widely used ionophores and four kinds of polymer matrices [poly(vinyl chloride) (PVC), polyurethane (PU), PVC/PU blend, and silicone rubber (SR)]. It was found that the PVC-based membranes, which provide the best performance among all other matrix-based membranes in the absence of nonionic surfactants, exhibited larger change in their potentiometric properties when nonionic surfactants are added to the sample solution. On the other hand, the sodium-selective SR-based membrane with calix[4]arene, potassium-selective PVC/PU- or SR-based membrane with valinomycin, and the calcium-selective SR-based membrane with ETH 1001 provide almost identical analytical performance in the presence and absence of Tween 20 or Tween 80 surfactants. The origin of nonionic surfactants effect was also investigated by interpreting the experimental results obtained with various matrices and ionophores. The results suggest that the nonionic surfactant extracted into the membrane phase unselectively form complexes with the primary and interfering ions, resulting in increased background potential and lower binding ability for the ionophore. Such effects should result in deteriorated detection limits, reduced response slopes and lower selectivity for the primary ions.

• Bulletin of the Korean Chemical Society
• /
• 제29권9호
• /
• pp.1774-1780
• /
• 2008

New PVC based polymeric membrane electrodes (PME) and coated glassy carbon electrodes (CGCE) based on synthesized Schiff base complexes of Co(III); [Co(Salen)$(PBu_3)_2$]$ClO_4$, [Co($Me_2$Salen)$(PBu_3)_2$]$ClO_4$, [Co(Salen)$(PBu_3)H_2O$]$ClO_4$; as anion carriers for potentiometric determination of $ClO_4\;^-$were studied. The PME and also CGCE electrodes prepared with [Co(Me2Salen)$(PBu_3)_2$]$ClO_4$ showed excellent response characteristics to perchlorate ions. The electrodes exhibited Nernstian responses to $ClO_4\;^-$ ions over a wide concentration range with low detection limits ($1.0 {\times} 10^{-6}\;mol\;L^{-1}$ for PME and $9.0 {\times} 10^{-7}\;mol\;L^{-1}$ for CGCE). The electrodes possess fast response time, satisfactory reproducibility, appropriate lifetime and, most importantly, good selectivity toward $ClO_4\;^-$ relative to a variety of other common inorganic anions. The potentiometric response of the electrodes is independent of the pH in the pH range 2.5-8.5. The proposed sensors were used in potentiometric determination of perchlorate ions in mineral water and urine samples. The interaction of the ionophore with perchlorate ions was shown by UV/Vis spectroscopy.

• 멤브레인
• /
• 제19권2호
• /
• pp.89-95
• /
• 2009

Poly(vinyl chloride) (PVC) 주사슬과 poly(hydroxyethyl acrylate) (PHEA) 곁사슬로 구성된 빗살모양의 PVC-g-PHEA 공중합체를 원자전달라디칼 중합을 통해 합성하였다. 이렇게 합성된 PVC-g-PHEA의 OH 그룹과 이미다졸 디카르복실릭산 (IDA)의 COOH 그룹과의 에스테르 반응에 의하여 가교된 전해질막을 제조하였다. 인산(PA)을 도핑하여 이미다졸-인산 착체를 형성한 결과, PA함량이 증가함에 따라 고분자 전해질막의 수소 이온 전도도가 증가하였다. 특히 100도 비가습 조건에서 수소 이온 전도도는 최대 0.011 S/cm까지 증가하였다. 만능 재료 시험기(UTM) 측정결과, 제조된 PVC-g-PHEA/IDA/PA 전해질막은 575 MPa의 높은 Young 모듈러스 및 기계적 강도를 보여주었다. 열분석 결과(TGA) 전해질막은 $200^{\circ}C$까지 열적으로 안정함을 확인하였다.

• Membrane and Water Treatment
• /
• 제3권2호
• /
• pp.123-131
• /
• 2012

This study investigated the extraction and stripping performance of PIMs consisting of PVC and Aliquat 336. Extraction and stripping of three representative heavy metals - namely $Cd^{2+}$, $Cu^{2+}$, and $Zn^{2+}$ - by the synthesized membranes were evaluated as a function of sodium chloride concentration and under different stripping solutions (0.01 M $HNO_3$, Milli-Q water, 0.01 M HCl and 0.01 M NaOH), respectively. Results reported here indicate that the formation of negatively charged metal chloride complex species was responsible for the extraction of the target metal to PIMs. Experimental results and thermodynamic modeling of the speciation of chloro metal complexes further confirm that the extraction selectivity between $Cd^{2+}$, $Cu^{2+}$ and $Zn^{2+}$ can be controlled by regulating the chloride concentration of the feed solution. An acidic solution without any chloride was the most effective stripping solution, followed by Milli-Q water, and a diluted hydrochloric acid solution. On the other hand, the stripping of metals from PIMs did not occur when a basic stripping solution was used.

• 약학회지
• /
• 제44권5호
• /
• pp.406-410
• /
• 2000

The present method is to describe a potentiometric norfloxacin electrode system characterized by a membrane, based on the use of norfloxacin (NF) complex with ion-association reagents. These complexes were dissolved in DMSO, DMF acetonitrile or acetone and dispersed in plasticized poly(vinyl chloride) matrix. The picric acid complex electrode exhibited near-Nernstian response for NF in acetate buffer solution (pH 4.0) with a slope of 53.03 mV/decade. And linear response over the range of 10$^{-5}$ to 10$^{-3}$M solution of NE. The ingredients in tablet, capsule and biological important organic acids were not interfere.

• 한국임상약학회지
• /
• 제6권2호
• /
• pp.32-40
• /
• 1996

The electrophysiological effects of benzopyran potassium channel openers (PCOs: lemakalim, KR-30450 and KR-30818) on the ischemia/reperfusion-induced arrythmias were investigated. In anesthetized rats, subjected to 45 min occlusion of the left anterior descending coronary artery (LAD) followed by 90 min reperfusion, ventricular arrythmias were identified according to the Lambeth Conventions by lead II ECG. Rats were intravenously given vehicle ($1\%$ DMSO), lemakalim, KR-30450, and KR-30818 alone or in combination with a selective $K_{ATP}$ blocker glibenclamide, 30 min prior to coronary occlusion. Compared to vehicle, lemakalim ($30{\mu}g/kg$ i.v.), the active enantiomer of cromakalim, had a tendancy to increase the duration of ventricular tachycardia (Vl) and ventricular fibrillation (VF), the number of premature ventricular complexes (PVC) and the incidence of VF, especially in the early post-occlusion peroid ($0\~15$ min), while increasing ST-segment elevation. Both KR-30450 ($30{\mu}g/kg$, i.v.) and KR-30818 (30, $100{\mu}g/kg$, i.v.) showed similar proarrhythmic effects to lemakalim (PVC, duration of VT, and incidence of VF) with a tendancy to decrease the duration of VF and ST-segment elevation. Unlike other PCOs, however, glibenclamide (0.3, 1.0 mg/kg) had opposite effects on the induction of arrhythmias (PVC, the duration of VF); it had a tendancy to increase the duration of VT with a slight elevation of ST-segment. It seems likely that glibenclamide (0.3 mg/kg, i.v.), reduced the effects of lemakalim or KR-30450 ($30{\mu}g/kg$, i.v.) on arrhythmias (PVC, VT, VF and ST-segment). These results indicate that, in the coronary occluded rat model of ischemia, lemikuiln and KR-30450 exert a proarrhythmic activity, the effect being considered related to the opening of KATP channel.