• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1474-1476
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• 2004

A sodium ion- selective electrode based on dibenzopyridino-18-crown-6 as membrane carrier was successfully prepared. The electrode exhibits a Nernstian response for $Na^+$ ions within the concentration range of $1.0\;{\times}\;10^{-4}-1.0\;{\times}\;10^{-1}$ M. The response time of the sensor is 20 s. The sodium ion-selective electrode exhibited comparatively good selectivities with respect to alkali, alkaline earth and some transition metal ions.

• Analytical Science and Technology
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• v.18 no.6
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• pp.491-494
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• 2005

The main component governing selectivity in ion-selective electrodes and optodes is the ionophore. For this reason, a member of natural products that possess selective ion-binding properties have long been sought after. By applying this principle, the performance of cyclosporin used as neutral carriers for calcium selective polymeric membrane electrode was investigated. The calcium ion-selective electrode based on cyclosporin gave a good Nernstian response of 26.6 mV per decade for calcium ion in the activity range $1{\times}10^{-6}M$ to $1{\times}10^{-2}M$. The optimized calcium ion-selective electrode displayed very comparable selectivity for $Ca^{2+}$ ion against alkali and alkaline earth metal ions, $Na^{2+}$, and $Mg^{2+}$ in particular.

• Journal of Biosystems Engineering
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• v.32 no.1 s.120
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• pp.37-43
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• 2007

This study was carried out to investigate the applicability of PVC membrane-based ion-selective electrodes for macronutrients (K, Ca, and N) by measuring of potassium, calcium, nitrate ions in hydroponic nutrient solution. The capabilities of two ion-selective membranes with varying chemical compositions for each ion were evaluated in terms of sensitivity, selectivity, and lifetime to choose sensing elements suitable for measuring typical ranges of nutrient concentrations in hydroponic solutions. The selected calcium and nitrate ion-selective membranes showed effectively sensitive responses to calcium and nitrate ions with lifetimes of 25 and 15 days, respectively. The addition of a cation additive to the potassium membrane cocktail allowed its sensitivity to be increased whereas its lifetime was reduced from 30 days to 10 days.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.405-408
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• 2001

New lipophilic triesters of calix[4]arene and calix[4]quinone are investigated as sodium ion-selective ionophores in poly(vinyl chloride) membrane electrodes. For an ion selective electrode based on calix[4]arene triester I, the linear response is 1 ${\times}$10-3.5 to 1 ${\times}$ 10-1 M of Na+ concentrations. The selectivity coefficients for sodium ion over alkali metal and ammonium ions are determined. The detection limit (logaNa+ = -4.50) and the selectivity coefficient (logKNa+,K+pot = -1.86) are obtained for polymeric membrane electrode containing calix[4]arene triester I.

• Journal of the Korean Electrochemical Society
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• v.9 no.3
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• pp.132-134
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• 2006

The main component governing selectivity in ion-selective electrodes and optodes is the ionophore. For this reason, a member of natural products that possess selective ion-binding properties have long been sought after. By applying this principle, the performance of tetracycline used as neutral carriers for cation selective polymeric membrane electrode was investigated. The cation ion-selective electrode based on tetracycline gave a good Nernstian response of 26.6 mV per decade for calcium ion in the activity range $1x10^{-6}M$ to $1x10^{-2}M$ with and without lipophilic additives. The optimized cation ion-selective membrane electrodes displayed very comparable potentiometric responses to various mono and di-valent cations of alkali and alkaline earth metal ions except $Mg^{2+}$.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.489-493
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• 2003

2-Mercaptobenzothiazole was used as a highly selective and efficient carrier for the uphill transport of silver ion through a chloroform bulk liquid membrane. In the presence of thiosulfate ion as a suitable metal ion acceptor in the receiving phase, the amount of silver transported across the liquid membrane after 180 min was 90 ± 3.0%. The selectivity and efficiency of silver ion transported from aqueous solutions containing equimolar mixtures of $Zn^{2+}, Cu^{2+}, Co^{2+}, Ni^{2+}, Cd^{2+}, Pb^{2+}, Bi^{3+}, Fe^{2+}, Fe^{3+}, Pd^{2+}, Mn^{2+}, Hg^{2+}, Sn^{2+}, Ca^{2+}, Mg^{2+}, K^+, Na^+ and Li^+$ were investigated.

• Fibers and Polymers
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• v.3 no.1
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• pp.14-17
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• 2002

Development of a novel fixed site carrier membrane (FCM), supported by PET fabric for metal ion separation is reported. The membranes were prepared by dipping PET fabric into the methylene chloride solution of Poly(5-vinyl-m-phe-nylene-m'-phenylene-32-crown-10) (P(VCE)), a polymeric metal ion carrier. It was found that the flux of mono-valent metal ion transported across the membrane is signif=cantly differed from each other and the flux decreases in the order $Cs^+$>$Rb^+$>$K^+$>$Na^+$>$Li^+$ irrespective to the anion except perchlorate anion. It was explained in terms of the stability of the complex, formed by crown ether unit of the P(VCE) and the various metal ions, meanwhile, the lower rate of transport in the presence of perchlorate anion was ascribed to its low hydrophilicity.

• International Journal of Control, Automation, and Systems
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• v.2 no.1
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• pp.23-38
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• 2004

We proposed the infinity control principle to evaluate the Biological function. The H infinity control was applied to the Sodium (Na) ion selective gating channel on the excitable cellular membrane of the neural system. The channel opening, closing and inactivation processes were expressed by movements of three gates and one inactivation blocking particle in the channel pore. The rate constants of the channel state transition were set to be voltage dependent. The temporal changes in amounts per unit membrane area of the channel states were expressed by means of eight differential equations. The biochemical mimetic used to complete the Na ion selective channel was regarded as noise. The control inputs for ejecting the blocking particle with plugging in the channel pore were set for the active transition from inactivated states to a closed or open state. By applying the H infinity control, we computed temporal changes in the channel states, observers, control inputs and the worst case noises. The present paper will be available for evaluating the noise filtering function of the biological signal transmission system.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.219-222
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• 2001

Membranes which selectively transport specific metals on an industrial scale is much useful in a number of applications, such as aqueous stream purification, catalyst and recycling of the reactants, the applications in metal ion sensing and so forth. Numerous studies have been already made to use liquid, supported liquid and, emulsion liquid membranes (LM) for selective carriers for metal ion transport. (omitted)

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.930-934
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• 2005

A chloroform membrane system containing a given mixture of benzylaza-12-crown-4 and oleic acid is introduced for the selective and efficient transport of $Pb^{2+}$ ion. The transport was capable of moving metal ions ‘up-hill’. In the presence of ${S_2O_3}^{2-}$ion as a suitable metal ion acceptor in the receiving phase, the amount of lead ion transport across the liquid membrane after 150 minutes is (95.0 ${\pm}$ 1.7)%. The selectivity and efficiency of lead transport from aqueous solution containing $Tl^+,\;Ag^+,\;Mg^{2+},\;Ca^{2+},\;Co^{2+},$ $Ni^{2+},\;Cu^{2+},\;Zn^{2+},\;Hg^{2+}$ and $Cd^{2+}$were investigated. In the presence of thiosulfate as a suitable masking agent in the source phase, the interfering effects of $Ag^+\;and\;Cu^{2+}$ were diminished drastically.