• Polymer(Korea)
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• v.34 no.4
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• pp.386-389
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• 2010

Thermal behaviors of water in the poly(acrylic acid) (PAA)/water mixtures with 0.1 M NaCl, HCl, and NaOH were investigated by DSC. It showed that adding ions in the mixtures affected the crystallization of water evidently. Compared with the PAA/water mixtures, the $T_m$ of freezable bound water in the mixtures with ions moved to lower values and varied with different cations and anions, due to the stabilization or destabilization of the hydrogen-bonding hydration between polymers and water molecules through ionic hydration. The content of non-freezable bound water in the non-crystalline phase of the PAA/water mixtures with ions was not constant, it increased with total water content gradually, owing to the more binding sites created by ions. The ions could change the distribution of different states of water in the polymer aqueous solutions evidently.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.14-22
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• 2004

The effect of cadmium ions on ligninolytic and decolourizing activities in cultures of two white-rot fungi, Cerrena unicolor and Trametes versicolor, were examined. Cadmium was added to the shallow stationary cultures growing on a liquid mineral medium. Both examined strains sorbed Cd ions in the first 24 hr of incubation. An appreciable stimulation of the activity of extracellular laccase (LAC) and inhibition of the extracellular manganese-dependent peroxidase (MnP) were simultaneously observed when 25 mgL^-1 and 50 mgL^-1 of cadmium ions were added to the cultures. On the other hand, the addition of cadmium ions also resulted in stimulating the decolorization activity of C. unicolor to decolorize Remazol Brilliant Blue R (RBBR) in the cultures, but decreasing it in the culture of T. versicolor, which is compared to the inhibition of MnP activity in this fungus. Our data indicate that the presence of Cd(II) ions can affect the ligninolytic activity of white-rot fungi. It was found that C. unicolor is a strain resistant to the presence of Cd ions in the liquid culture media, and has a potential to use this strain for bioremediation of sites contaminated with both heavy metals and aromatic pollutants.

• Korean Journal of Microbiology
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• v.14 no.2
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• pp.75-83
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• 1976

Three conmmercial cellulases prepared from Penicillium notatum(cellulalse[K]), Trichoderma viride(cellulase[J]) and Aspergillus niger(cellulase[A]) were nalyzed with respect to their relative purity, activity and the effects of several metal ions on their activities. The activity of cellulase[K] was the strongest of all and that of cellulase[A] being the weaker. The purity of cellulalse[K] was the highest while that of cellulase[J] was the lowest. Under the assay conditions, the optimum concentrations of $Zn^{++}$ and $Mg^{++}$ ions for the activity of cellulase[K] was the highest while that of cellulase[J] was the lowest. Under the assay conditions, the optimum concentrations of $Zn^{++}$ and $Mg^{++}$ ions for the activity of cellulalse[K] was the highest while that of cellulase [A] being weaker. The purity of cellulase[K] was the highest while that of cellulase[J] was the lowest. Under the assay conditions, the optimum concentrations of $Zn^{++}$ and $MG^{++}$ ions for the activity of cellulase[K] were 2 and 7mM while those of cellulase[A] were 5 and 6 mM respectively and those of cellulase[J] were 3mM for both ions. Cellulase[K] and cellulase[J] were more strongly activated by $Zn^{++}$ than $Mg^{++}$ and cellulase[J] by $Mg^{++}$ than $Zn^{++}$. Both $Cu^{++}$ and $Mn^{++}$ ions inhibited by these metal ions. the inhibitory effects of $Mn^{++}$ ions for enzyme activities were stronger than $Cu^{++}$ ions. The Ki values of $Cu^{++}$ and $Mn^{++}$ for cellulase[K] were found to be 6.1 and 0.7mM, those of cellulase[J] were 2.6 and 0.32 mM, and those of cellulalse[A] were 2.0 and 0.2 mM respectively. Both $Cu^{++}$ and $Mn^{++}$ ions showed a pattrn of competitive inhibition of the enzyme activity. When Na-CMC was used as substrate, the Km and V values of celluase [K] were calculated to be $2.0{\times}10^{-4}mM$ and 3.43mmoles/hour, those of cellulase[J] were $2.4{\times}10^{-4}mM$ and 3.77mmoles/hour, and those of cellulase[A] were $4.0{\times}10^{-4}mM$ and 4.00mmoles/hour respectively.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1121-1126
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• 2002

Two anhydrous crystal structures of fully dehydrated Cd2+ - and Cs+ -exchanged zeolite X, Cd32Cs28Si100Al92O384 (Cd32Cs28-X: a = 24.828(11) $\AA)$ and fully dehydrated Cd,sup>2+ - and Rb+ -exchanged zeolite X, Cd28Rb36Si100Al92O384 (Cd28Rb36-X: a = 24.794(2) $\AA$), have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at $21(1)^{\circ}C.$ The structures were refined to the final error indices, R1 = 0.058 and R2 = 0.065 with 637 reflections for Cd32Cs28-X and R1 = 0.086 and R2 = 0.113 with 521 reflections for Cd28Rb36-X for which I > $3\sigma(I)$. In the structure of Cd,sub>32Cs28-X, 16 Cd2+ ions fill the octahedral sites I at the centers of the double six rings (Cd-O = $2.358(8)\AA$ and O-Cd-O = $90.8(3)^{\circ}$ ). The remaining 16 Cd2+ ions occupy site II (Cd-O = $2.194(8)\AA$ and O-Cd-O = $119.7(4)^{\circ})$ and six Cs+ ions occupy site II opposite to the single six-rings in the supercage; each is $2.322\AA$ from the plane of three oxygens (Cs-O = 3.193(13) and O-Cs-O = $73.0(2)^{\circ}).$ Aboutten Cs+ ions are found at site II', $1.974\AA$ into the sodalite cavity from their three oxygen plane (Cs-O = $2.947(8)\AA$ and O-Cs-O = $80.2(3)^{\circ}).$ The remaining 12 Cs+ ions are distributed over site III' (Cs-O = 3.143(9) and O-Cs-O= $59.1(2)^{\circ})$. In the structure of Cd28Rb36-X, 16 Cd2+ ions fill the octahedral sites I at the center of the double-sixrings (Cd-O = 2.349(15) and O-Cd-O = $91.3(5)^{\circ}$ ). Another 12 Cd2+ ions occupy two different II sites (Cd-O = $2.171(18)/2.269(17)\AA$ and O-Cd-O = $119.7(7)/113.2(7)^{\circ}).$ Fifteen Rb+ ions occupy site II (Rb-O = $2.707(17)\AA$ and O-Rb-O = $87.8(5)^{\circ}).$ The remaining 21 Rb+ ions are distributed over site III' (Rb-O = $3.001(16)\AA$ and O-Rb-O = $60.7(4)^{\circ})$. It appears that the smaller and more highly charged Cd2+ ions prefer sites I and Ⅱ in that order, and the larger Rb+ and Cs+ ions, which are less able to balance the anionic charge of the zeolite framework, occupy sites II and II' with the remainder going to the least suitable site in the structure, site III'.The maximum Cs+ and Rb+ ion exchanges were 30% and 39%, respectively. Because these cations are too largeto enter the small cavities and their charge distributions may be unfavorable, cation-sieve effects might appear.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.251-256
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• 2007

The crystal structure of fully dehydrated partially Cs+-exchanged zeolite X, [Cs52Na40Si100Al92O384], a = 24.9765(10) A, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21 °C. The crystal was prepared by flow method for 5 days using exchange solution in which mole ratio of CsOH and CsNO3 was 1 : 1 with total concentration of 0.05 M. The crystal was then dehydrated at 400 °C and 2 × 10-6 Torr for 2 days. The structure was refined to the final error indices, R1 = 0.051 and wR2 (based on F2) = 0.094 with 247 reflections for which Fo > 4σ (Fo). In this structure, about fifty-two Cs+ ions per unit cell are located at six different crystallographic sites with special selectivity; about one Cs+ ion is located at site I, at the centers of double oxygen-rings (D6Rs), two Cs+ ions are located at site I', and six Cs+ ions are found at site II'. This is contrary to common view that Cs+ ions cannot pass sodalite cavities nor D6Rs because six-ring entrances are too small. Ring-opening by the formation of ?OH groups and ring-flexing make Cs+ ions at sites I, I', and II' enter six-oxygen rings. The defects of zeolite frameworks also give enough mobility to Cs+ ions to enter sodalite cavities and D6Rs. Another six Cs+ ions are found at site II, thirty-six are located at site III, and one is located at site III' in the supercage, respectively. Forty Na+ ions per unit cell are located at two different crystallographic sites; about fourteen are located at site I, the centers of D6Rs and twenty-six are also located at site II in the supercage. Cs+ ions and Na+ ions at site II are recessed ca. 0.34(1) A and 1.91(1) A into the supercage, respectively. In this work, the highest exchange level of Cs+ ions per unit cell was achieved in zeolite X by conventional aqueous solution methods and it was also shown that Cs+ ion could pass through the sixoxygen rings.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.243-247
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• 1989

Two crystal structures of dehydrated $Ag^+\;and\;Ca^{2+}$ exchanged zeolite A, $Ag_2Ca_$5-A, reacting with 0.01 Torr of Cs vapor at $200^{\circ}C$ for 2 hours and 0.1 Torr of Cs vapor at $250^{\circ}C$ for 48 hours, respectively, have been determined by single crystal X-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at $21(1)^{\circ}C$. The stoichiometry of first crystal was $Ag_2Ca_5$-A (a = 12.294(1)${\AA}$), indicating that Cs vapor did not react with cations in zeolite A and that of second crystal was $Ag_2Cs_{10}$-A (a = 12.166(1)${\AA}$), indicating that all $Ca^{2+}$ ions were reduced by Cs vapor and replaced by $Cs^+$ ions. Full-matrix least-squares refinements of $Ag_2Ca_5-A\;and\;Ag_2Cs_{10}$-A has converged to the final error indices, $R_1\;=\;0.041\;and\;R_2$ = 0.048 with 227 reflections, and $R_1\;=\;0.117\;an\;n\;fdd\;R_2$ = 0.120 with 167 reflections, respectively, for which I > $3{\sigma}$(I). In the structure of $Ag_2Ca_5$-A, both $Ag^+$ ions and $Ca^{2+}$ ions lie on two crystal symmetrically independent threefold axis sites on the 6-rings; $2\;Ag^+$ ions are recessed 0.33 ${\;AA}$ from the (111) planes of three O(3) oxygens and 5 $Ca^{2+}$ ions lie on the nearly center of each 6-oxygen planes. In the structure of $Ag_2Cs_{10}-A,\;Cs^+$ ions lie on the 5 different crystallographic sites. 3 $Cs^+$ ions lie at the centers of the 8-rings at sites of D4h symmetry. 6 $Cs^+$ ions lie on the threefold axes of unit cell: $4\;Cs^+$ ions are found deep in the large cavity and 2 $Cs^+$ ions are found in the sodalite cavity. One $Cs^+$ ion is found in the large cavity near a 4-ring.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.740-746
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• 2005

In this article, we report the tandem mass spectrometry investigations for the electron capture efficiencies of the protons belonging to the different locations (generations) in a poly(propylene imine) dendrimer with three layers of a repeat unit (named as the third generation dendrimer). The employed tandem mass spectrometry methods include SORI-CAD (sustained off-resonance irradiation collisional activation dissociation) and ECD(electron capture dissociation) mass spectrometry. We obtained SORI-CAD spectra for the dendrimer ions in the different charge states, ranging from 2+ to 4+. The analysis of fragmentation sites provides the information as to where the protons are distributed among various generations of the dendrimer. Based upon this, a new strategy to study the electron capture efficiencies of the protons is utilized to examine a new type of triplycharged ions by SORI-CAD, i.e., the 3+ ions generated from the charge reduction of the native 4+ ions by ECD: (M+4H)$^{4+}\;+\;e^-\;{\rightarrow}$ (M+4H)$^{3+\bullet}$ ${\rightarrow}\;({H^{\bullet}}_{ejected}$) + (M+3H)$^{3+}\;\rightarrow$ CAD. Interestingly, comparison of these four SORICAD spectra indicates that the proton distribution in the charge-reduced 3+ ions is very close to that in the native 4+ ions. It further suggests that in this synthetic polymer ($\sim$1.7 kDa) with an artificial architecture, the electron capture efficiencies of the protons are actually insensitive to where they are located in the molecule. This is somewhat contradictory to common expectations that the protons in the inner generations may not be well exposed to the incoming electron irradiation as much as the outer ones are, thus may be less efficient for electron capture. This finding may carry some implications for the case of medium sized peptide ions with similar masses, which are known to show no obvious site-specific fragmentations in ECD MS.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.688-692
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• 2002

The aminomethylation of phenols with para-substituents by the Mannich reaction has successfully been accomplished to produce the Mannich bases 2-6. The compounds 7-8 have also been synthesized in order to identify the effect of the side arms and t he macrocycle in the complex formation. Protonation constants and stability constants of the double armed diaza-18-crown-6 ethers 2-7 with metal ions have been determined by potentiometric method at 25 $^{\circ}C$ in 95 % methanol solution. Under a basic condition (pH > 8.0), the double-armed crown ethers 2-6 revealed stronger interaction with divalent metal ions than the simple diazacrown ether 1. The stability constants with these metal ions were Co 2+ < Ni2+ < Cu2+ > Zn 2+ in increasing order, which are in accordance with the order of the Williams-Irving series. The stability constants with alkali earth metal ions were Ca 2+ < Sr 2+ < Ba 2+ in increasing order, which may be explained by the concept of size effect. It is noteworthy that the hosts 2-6, which have phenolic side arms and a macrocycle, bind stronger with metal ions than the hosts 1 and 7. On the other hand, the host 8, which has phenolic side arms with a pyperazine ring,provided comparable stability constants to those with the host 3. These facts demonstrate that phenolic side arms play a more important role than the azacrown ether ring in the process of making a complex with metal ions especially in a basic condition. In particular, the log KML values for complexation of divalent metal ions with the hosts 2-6 had the sequence, i.e., 2 (R=OCH3) < 3 (R=CH3) < 4 (R=H) < 5 (R=Cl) < 6 (R=CF3). The stability constants of the hosts 5 and 6 containing an electron-withdrawing group are larger than those of the hosts 2 and 3 containing an electron-donating group. This substituent effect is attributed to the solvent effect in which the aryl oxide with an electron-donating group has a tendency to be tied strongly with protic solvents.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.232-235
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• 2002

An 150 kV gas cluster ion accelerator was fabricated and assessed. The change of surface morphology and surface roughness were examined by an atom force microscope (AFM) after irradiation of $CO_2$ gas clusters on Si (100) surfaces at the acceleration voltages of 50 kV. The density of hillocks induced by cluster ion impact was gradually increased with the dosage up to 5$\times$10$^{11}$ ions/$\textrm{cm}^2$. At the boundary of the ion dosage of 10$^{12}$ ions/$\textrm{cm}^2$, the density of the induced hillocks was decreased and RMS (root mean square) surface roughness was not deteriorated further. At the dosage of 5x10$^{13}$ ions/$\textrm{cm}^2$, the induced hillocks completely disappeared and the surface became very flat. In addition, the irradiated region was sputtered. $CO_2$ cluster ions are irradiated at the acceleration voltage of 25 kV to remove hillocks on indium tin oxide (ITO) surface and thus to attain highly smooth surfaces. $CO_2$ monomer ions are also bombarded on the ITO surface at the same acceleration voltage to compare sputtering phenomena. From the AFM results, the irradiation of monomer ions make the hillocks sharper and the surfaces rougher On the other hand, the irradiation of $CO_2$ cluster ions reduces the hight of hillocks and planarize the ITO surfaces. From the experiment of isolated cluster ion impact on the Si surfaces, the induced hillocks m high had the surfaces embossed at the lower ion dosages. The surface roughness was slightly increased with the hillock density and the ion dosage. At higher than a critical ion dosage, the induced hillocks were sputtered and the sputtered particles migrated in order to fill valleys among the hillocks. After prolonged irradiation of cluster ions, the irradiated region was very flat and etched.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.627-641
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• 2006

Atmospheric $PM_{2.5}$ and $PM_{10}$ were measured to investigate their levels and water-soluble ions(${SO_4}^{2-},\;{NO_3}^-,\;{NO_2}^-,\;Cl^-,\;{NH_4}^+,\;Na^+,\;Ca^{2+},\;Mg^{2+},\;and\;K^+$) in Daegu between February 17 and April 18, 2006. Four Asian dust episodes during the period were examined for the influence of Asian dust on the particulate properties. Daily $PM_{2.5}\;and\;PM_{2.5-10}$ concentrations ranged between $10.83{\sim}136.76{\mu}g/m^3$ with a mean of $38.43{\mu}g/m^3$ and $16.13{\sim}409.13{\mu}g/m^3$ with a mean of $79.98{\mu}g/m^3$, respectively. For all measured ions the mean fractions of $PM_{2.5}\;and\;PM_{2.5-10}$ were 51.8% and 28.9% being lowered to 30.7% and 9.4%, respectively, during the dust episodes. Secondary ions (i.e., non-sea salt ${SO_4}^{2-},\;{NO_3}^-,\;and\;{NH_4}^+$) contributed 44.3% and 14.8% to $PM_{2.5}\;and\;PM_{2.5-10}$, respectively, with a decreased contribution during the episodes. The average equivalent ratio of ${NH_4}^+$ to the sum of ${SO_4}^{2-}\;and\;{NO_3}^-$ was 0.99 and 0.89 for $PM_{2.5}\;and\;PM_{2.5-10}$, respectively, indicating high source strength of $NH_3$ and its dominance in the neutralization of the acidic ions. Correlations and charge balance between ions suggest that neutralization of the acidic ions results in substantial depletions of carbonate both in $PM_{2.5}\;and\;PM_{2.5-10}$ and chloride only in $PM_{2.5}$.