• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.149-149
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• 2000

Alkali and alkali-earth metal on si(001) surface has been investigated widly for both scientific and technological aspects. In particular, the Ba/Si(001) system has been studied by several groups and they reported many phases such as (2$\times$3), (2$\times$4) and c(6$\times$2) 표 LEED and AES for various temperature and coverages. But there has not been the result of the atomic structure for these phases. Recently some works about the atomic structure of Ba/Si(001) at only room temperature were presented. In this study, we investigated 3-dimensional atomic structure and growth mode of Ba layer on si(001) by coaxial impact collision ion scattering spectroscopy (CAISS) at room temperature and high temperature.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.473-482
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• 2012

A novel malemide epoxy containing Co(II), Ni(II) and Cu(II) ions have been synthesized by curing malemide epoxy resin (MIEB-13) and Co(II), Ni(II) and Cu(II) complexes of macrocyclic bis-hydrazone Schiff base. The Schiff base was synthesized by reacting 1,4-dicarbnyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol. The Schiff base and its Co(II), Ni(II) and Cu(II) complexes have been characterized by elemental analyses, spectral (IR, $^1H$ NMR, UV-vis., FAB mass, ESR), thermal and magnetic data. The curing reaction of maleimide epoxy compound with metal complexes was studied as curing agents. The stability of cured samples was studied by thermo-gravimetric analyses and which have excellent chemical (acid/alkali/solvent) and water absorption resistance. Further, the scanning electron microscopy (SEM) and definitional scanning colorimetric (DSC) techniques were confirmed the phase homogeneity of the cured systems.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.242-246
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• 2005

The heavy metal analysis (Cd, Pb, Cu, Cr, Zn, Ni) with various extraction methods was performed using the certified sample and real soil sample. In case of the certified samples, $10.5{\sim}118%$ of recovery was showed with various ranges depend on the metal kinds and extraction methods. Also, the alkali-digestion method was showed the proper results by applying in hexavalent chromium. In case of real sample, compared to amounts of heavy metals extracted using 0.1N-HCl, those extracted using acid digestion are higher by $3{\sim}24$ times in Cu, $1.1{\sim}1.5$ times in Cd, $2{\sim}23$ times in Pb, $3{\sim}104$ times in Zn, $12{\sim}101$ times in Ni, $30{\sim}202$ times in Cr. There is no considerable difference between four acid digestion methods.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.567-570
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• 2008

A new pyrene appended diaza-18-crown-6 ether derivative 1 has been prepared and its fluoroionophoric properties toward transition metal ions were investigated. Compound 1 exhibited a high Hg2+-selectivity over other transition metal ions as well as alkali and alkaline earth metal ions in aqueous acetonitrile solution. The ratiometric analysis of the monomer and excimer emissions of pyrene successfully signals the presence of Hg2+ ions. The detection limit for Hg2+ ions was found to be 3.1 ´ 10-6 M in 50% aqueous acetonitrile solution at pH 8.1. Competition experiments also suggest that the compound could be utilized as a selective and sensitive fluorescent chemosensor for the analysis of micromolar Hg2+ ions in physiological and environmental samples.

• Journal of the Korean Ceramic Society
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• v.30 no.11
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• pp.967-973
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• 1993

The effect on the hydration of cement was that Cu and Pb reacted with alkali to form soluble hydrates at theinitial stage and then there followed a slow reaction forming insoluble metal hydroxides. These hydroxides were deposited on the surface of cement particles providing a barrier against further hydration. But as a slow reaction continued, the insoluble layers were eventually destroyed and the hydration reaction resumed. Thereafter, another retardation occured by restricting the polymerization of silicates, shown by FT-IR spectroscopy analysis. In the case of Cr, as its reaction with cement caused H2O, the coordinator of Cr complex, to replace or polymerize with OH-, the formation of Cr complex promoted the leakage of OH- and increased the heat of dissolution. So the total heat evolution during hydration was larger than that in the case of Pb or Cu. The retarding effect of heavy metal ions was in the order Pb>Cu>Cr.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.207-211
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• 1998

Potentiometric characteristics of DOS plasticized PVC-based membranes containing upper-rim calix[4]crown neutral carrier to various metal cations and protonated alkylamines have been examined. Although the calix[4]crown-based membrane electrodes exhibited substantial emf responses to alkali and alkaline earth metal cations, their high detection limits (- log[Cs+]=4.5) and sub-Nernstian response slopes (48 mV/pCs+) to the most selective cation, cesium, indicate that the metal cation complexing ability of calix[4]crown is much weaker than that of macrocyclic crown ethers. However, the calix[4]crown-based membrane electrodes exhibited near-Nernstian response slopes (56 mV/decade for hexylNH3+) with low detection limits (log[hexylNH3+]= - 6.7) to most alkylammonium ions compared to those of blank (DOS plasticized PVC membrane with no ionophore) or crown ether-based membranes. While the selectivity patterns of blank and crown ether-based membranes are determined primarily by the lipophilicity of alkylammonium ions, the membranes doped with calix[4]crown ionophore could effectively discriminate the steric shapes of nonpolar alkyl groups of alkylammonium ions.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.23-29
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• 2003

Setschenow constants of six alkali and alkaline earth metal-based electrolytes (i.e., NaCl, KCl, CaCl$_2$, K$_2$SO$_4$, Na$_2$SO$_4$, NaClO$_4$) for three polycyclic aromatic hydrocarbons (PAHs) (i.e., naphthalene, pyrene, and perylene) were investigated to evaluate the influence of a variety of inorganic salts on the aqueous solubility of PAHs. Inorganic salts showed a wide range of K$\_$s/ values (L/mol), ranging from 0.1108 (NaClO$_4$) to 0.6680 (Na$_2$SO$_4$) for naphthalene, 0.1071 (NaClO$_4$) to 0.7355 (Na$_2$SO$_4$) for pyrene, and 0.1526 (NaClO$_4$) to 0.8136 (Na$_2$SO$_4$) for perylene. In general, the salting out effect of metal cations decreased in the order of Ca$\^$2+/>Na$\^$+/>K$\^$+/. The effect of SO$_4$$\^$2-/>Cl$\^$-/>ClO4$\^$-/ was observed for anions of inorganic salts. The K$\_$s/ values decreased in the order of perylene>pyrene>naphthalene for K$_2$SO$_4$. However, the order of decreasing salting out effect for NaCl, KCl, CaCl$_2$, and NaClO$_4$ was perylene>naphthalene>pyrene. Hydration free energy of the 1:1 and 2:1 alkali and alkaline earth metal-based inorganic salts solution was observed to have a meaningful correlation with Setschenow constants. Thermodynamic interactions between PAH molecules and salt solution can be of importance in determining the magnitude of salting out effect for PAHs at a given salt solution.

• Journal of Pharmaceutical Investigation
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• v.1 no.1
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• pp.101-108
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• 1971

The stability and toxicity test for p.p'-DDT, DDVP and dipterex that put to used sample in this study effects is follows A. about p.p'-DDT (1) In elevating the stability of p.p'-DDT, best stabilizing solvent was benzene. (2) The stability-agent has no difficulty as long as it not contain metal ion for instance $Z_n^{2+}$,$C_r^{3+}$,$Al^{3+}$,and $Fe^{2+or3+}$ but in case of contain $F_e^{3+}$, the combination of salicylaminoguanidine is best effective. (3) Using this product for water-suspension, We must use span 40 for stability agent and adding it at the same time. (4) We must use container which does not week alkali and metal ion but it is to preserved in tight light-resistant container. (5) The stopper of container is adapted with above-mentioned condition of container, but it is better not to use metal material. (6) This product needs opening ventilation more than 30 minutes after diffusion or spray and in the room we remove cause of remained poison by cleaning the bottom. B. about DDVP and Dipterex (1) Benzene or toluene in best solvent to preserve stability of DDVP and Dipterex. (2) Span 40 is superior for stability agent of this product and second is span 80. (3) The pH of solution is very stable in pH 5-6 and comparative stable in alkali more than p,p'-DDT. (4) Container is to preserved in tight, lightresistant container and especially be careful of outflow and inflow of water. (5) Because this product is centeral stimulant poison, we must pay attention to prevent cause of contact diadermic toxicity after use.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1789-1793
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• 2014

Pseudo-first-order rate constants ($k_{obsd}$) have been measured spectrophotometrically for the reactions of 5-nitro-8-quinolyl nicotinate (4) and 5-nitro-8-quinolyl isonicotinate (5) with alkali metal ethoxides (EtOM; M = K, Na and Li) in anhydrous ethanol at $25.0{\pm}0.1^{\circ}C$. The plots of $k_{obsd}$ vs. [EtOM] curve slightly upward for the reactions with EtOK and EtONa but are linear for the reactions with EtOLi and for those with EtOK in the presence of 18-crown-6-ether. Dissection of $k_{obsd}$ into $k_{EtO^-}$ and $k_{EtOM}$ (i.e., the second-order rate constants for the reactions with the dissociated $EtO^-$ and ion-paired EtOM, respectively) has revealed that the reactivity increases in the order $EtO^-{\approx}EtOLi$ < EtOK < EtONa for the reactions of 4 and EtOLi < $EtO^-$ < EtOK < EtONa for the reactions of 5. Comparison of the kinetic results for the reactions of 4 and 5 with those reported previously for the corresponding reactions of 5-nitro-8-quinolyl benzoate (2) and picolinate (3) has revealed that the esters possessing a pyridine ring (i.e., 3-5) are significantly more reactive than the benzoate ester 2 due to the presence of the electronegative N atom (e.g., 2 << 3 < 4 < 5). It has been concluded that $M^+$ ion catalyzes the reactions of 3-5 by increasing the electrophilicity of the reaction center through a five-membered cyclic transition state (TS) for the reaction of 3 and via a four-membered cyclic TS for the reactions of 4 and 5.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.200-205
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• 2016

With high specific surface area and pore structural diversity, MOFs show important applications in gas storage, catalysis, sensing, separation, and biomedicine. However, the stability of the structure of MOFs has restricted their application and development. In this study, zirconium metal organic frameworks with 9,10-dicarboxylic acid anthracene as ligand, named UIO-66 ($H_2DCA$), were synthesized and their properties and structures were characterized by XRD, SEM, and $N_2$ adsorption. We focus on the stability of the structure of UIO-66 ($H_2DCA$) under different conditions (acid, alkali, and water). The structural changes or ruins of UIO-66 ($H_2DCA$) were traced by means of XRD, TG, and FT-IR under different conditions. The results show that the UIO-66 ($H_2DCA$) materials are stable at 583 K, and that this structural stability is greatly influenced by different types of acid and alkali compounds. Importantly, we found that the structures maintain their stability in environments of nitric acid, triethylamine, and boiling water.