• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.117-123
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• 2021

The effects of electrolyte concentration on the electrochemical properties of Fe4[Fe(CN6)]3(FeHCF) as a novel active material for the electrode of aqueous zinc-ion batteries was investigated. The electrochemical reactions and structural stability of the FeHCF electrode were significantly affected by the electrolyte concentration. In the electrolyte solutions of 1.0-7.0 mol dm-3, the charge-discharge capacities increased with increasing electrolyte concentration, however gradually decreased as the cycle progressed. On the other hand, in the 9.0 mol dm-3 electrolyte solution, the initial capacity was relatively small, however showed good cyclability. Additionally, the FeHCF electrode after five cycles in the former electrolyte solutions, had a change in crystal structure, whereas there was no change in the latter electrolyte solution. This suggests that the performance of the FeHCF electrode is greatly influenced by the hydration structure of zinc ions present in electrolyte solutions.

• Toxicological Research
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• v.29 no.2
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• pp.143-147
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• 2013

Cyanogenic glycosides are HCN-producing phytotoxins; HCN is a powerful and a rapidly acting poison. It is not difficult to find plants containing these compounds in the food supply and/or in medicinal herb collections. The objective of this study was to investigate the distribution of total cyanide in nine genera (Dolichos, Ginkgo, Hordeum, Linum, Phaseolus, Prunus, Phyllostachys, Phytolacca, and Portulaca) of edible plants and the effect of the processing on cyanide concentration. Total cyanide content was measured by ion chromatography following acid hydrolysis and distillation. Kernels of Prunus genus are used medicinally, but they possess the highest level of total cyanide of up to 2259.81 $CN^-$/g dry weight. Trace amounts of cyanogenic compounds were detected in foodstuffs such as mungbeans and bamboo shoots. Currently, except for the WHO guideline for cassava, there is no global standard for the allowed amount of cyanogenic compounds in foodstuffs. However, our data emphasize the need for the guidelines if plants containing cyanogenic glycosidesare to be developed as dietary supplements.

• The Korean Journal of Mycology
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• v.14 no.2
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• pp.101-107
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• 1986

The properties of carboxyl proteinase which was contained in Poria cocos (Schw.) Wolf were investigated by means of the purification with 0.65 ammonium sulfate saturation, DEAE cellulose and Sephadex G-75 gel filtration. This enzyme was found to hydrolyze only peptide bond between glutamyl-L-tyrosine of carbobenzoxy-L-glutamyl-L-tyrosine among the synthetic substrates of carbobenzoxy-L-glutamyl-L-tyrosine, hippuryl- L-phenylalanine and hippuryl-L-arginine. This enzyme was inhibited by $Zn^{+2},\;Fe^{+2},\;Ca^{+2},\;CN^{-1},\;P_2O_7^{-4}$ ions, but stimulated by $Hg^{+2}$ ion. Also, this enzyme was inhibited by organic compounds such as L-lysine, L-phenylalanine, hippuryl-L-phenylalanine, diazoacetyl-DL-norleucine methyl ester (DAN) and 1,2-epoxy-3-(P-nitrophenoxy)propane(EPNP). In particular, the activity was inhibited by L-lysine till 20 minutes of preincubation time rapidly, and by DAN in the presence of $Cu^{+2}$ ion more rapidly after 30 minutes than DAN in the absence of $Cu^{+2}$ ion. L-Lysine was found to be a competitive inhibitor and its $K_i$ value was determined to be 0.12 mmole by Dixon plot.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.140-145
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• 1996

Silver deposits formed on copper substrates by replacement reactions show poor adhesion, and a silver film plated on such a deposit does not adhere. Silver ion makes a highly stable complex with cyanide ion, so that in a silver cyanide solution, the activity of silver ion is very small. This is one of the reasons for the universal use of cyanide baths in the industrial silver plating. However, the consideration of the difference between the values of the stability constants for bath the silver-iodide complex and the copper-iodide complex suggest that the rate of replacement deposition of silver on the copper substrate in si]ver-potassium iodide solution, could be comparatively low. To confirm this, the rate of replacement deposition of silver in both a silver-potassium iodide solution ($AgNO_3$0.10 mol/L, KI 2.00 mol/L ) and a strike silver plating bath (AgCN 0.028 mol/L, KCN 1.15 mol/L ) was estimated from the current density corresponding to the point of intersection of the anodic and the cathodic polarization curves. These estimated values were almost the same, and it is suggested that the silver-potassium iodide solution is not only a cyanide free silver plating bath capable of employing a copper substrate but a silver plating bath which requires no strike plating.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.76-81
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• 2011

The protease produced by a Bacillus pumilus CN8 strain was purified by DEAE-Cellulose-52 ion exchange. It has a molecular weight of approximately 96,920 Dalton. In the present study, this protease showed strong activity over a broad range of pH (6.5-9.5) and temperature from $40^{\circ}C$ to $60^{\circ}C$, and the protease performed the maximal activity at pH 7.3 at $42^{\circ}C$. The effect of metal ions on protease activity showed that $K^+$ could slightly increase the protease activity, and other ions such as $Zn^{2+}$, $Fe^{2+}$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$ had no significant activation or inhibition to the protease (P> 0.05), and the more important is that $Cu^{2+}$, $Mn^{2+}$, $Sn^{2+}$, $Cd^{2+}$ had a strong inhibitory effect on the protease activity.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.511-515
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• 1995

Since much studies have been performed concerning the electrochemical behaviors and the practical applications of PB based devices, little has yet reported to investigate the best condition for the preparation for PB thin films. As considered some factors(peak shape, peak current, and peak separation) from the i-V curves, the optimal condition in the film growth were investigated under various immersion solutions. An electron-transfer processes of Fe2+/Fe3+ and Fe(CN)63-/4- redox couples were considered by measuring the observed currents as a function of the rotation velocity. The standard heterogeneous electron-transfer rates for these films and bare Au disc electrode in 10-3 M Fe2+/Fe3+ solution, applied at +0.65 V vs. SCE, were 6.14 × 10-3 and 7.78 × 10-3 cm/s, respectively, obtained using a rotating disc electrode. In case of the addition of potassium ion, the rate constants for these Fe2+/Fe3+ system on thin films of PB and bare electrode were given a little high values. The electron transfer rate for 10-3 M Fe(CN)63-/4- were 4.55 × 10-3 and 6.84 × 10-3 cm/s, respectively. The conductivity as directly determined during obtained the voltammogram, was 2.2 × 10-7 (Ω·cm)-1. This value is similar magnitude to that calculated from bulk sample.

• Korean Journal of Materials Research
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• v.31 no.3
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• pp.162-171
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• 2021

Dry etching of copper thin films is performed using high density plasma of ethylenediamine (EDA)/hexafluoroisopropanol (HFIP)/Ar gas mixture. The etch rates, etch selectivities and etch profiles of the copper thin films are improved by adding HFIP to EDA/Ar gas. As the EDA/HFIP concentration in EDA/HFIP/Ar increases, the etch rate of copper thin films decreases, whereas the etch profile is improved. In the EDA/HFIP/Ar gas mixture, the optimal ratio of EDA to HFIP is investigated. In addition, the etch parameters including ICP source power, dc-bias voltage, process pressure are varied to examine the etch characteristics. Optical emission spectroscopy results show that among all species, [CH], [CN] and [H] are the main species in the EDA/HFIP/Ar plasma. The X-ray photoelectron spectroscopy results indicate the formation of CuCN compound and C-N-H-containing polymers during the etching process, leading to a good etch profile. Finally, anisotropic etch profiles of the copper thin films patterned with 150 nm scale are obtained in EDA/HFIP/Ar gas mixture.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1781-1786
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• 2007

Two copper(II) complexes, [CuL3](ClO4)2 bearing one N-CH2CH2CONH2 group as well as one N-CH2CH2CN group and [CuL4](ClO4)2 bearing two N-CH2CH2CONH2 groups, have been prepared by the selective hydrolysis of [CuL2](ClO4)2 (L2 = C-meso-1,8-bis(cyanoethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). The complex [CuL5](ClO4)2 bearing one N-CH2CH2C(=NH)OCH3 and one N-CH2CH2CN groups has been prepared as the major product from the reaction of [CuL2](ClO4)2 with methanol in the presence of triethylamine. In acidic aqueous solution, the N-CH2CH2C(=NH)OCH3 group of [CuL5](ClO4)2 undergoes hydrolysis to yield [CuL6](ClO4)2 bearing both N-CH2CH2COOCH3 and N-CH2CH2CN groups. The crystal structure of [CuL5](ClO4)2 shows that the complex has a slightly distorted square-pyramidal coordination polyhedron with an apical Cu-N (N-CH2CH2C(=NH)OCH3 group) bond. The apical Cu-N bond distance (2.269(3) A) is ca. 0.06 A longer than the apical Cu-O (N-CH2CH2CONH2 group) bond of [CuL4](ClO4)2. The pendant amide group of [CuL3](ClO4)2 is involved in coordination. The carboxylic ester group of [CuL6](ClO4)2 is also coordinated to the metal ion in various solvents but is removed from the coordination sphere in the solid state.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.819-823
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• 1995

Thin films of two kinds of Prussian Blue (PB)-modified, using iron(Ⅲ) complex instead of conventional FeCl3, were prepared on a gold substrate and these films were able to be electrochemically reduced in potassium nitrate solution. In case of PB-modified films prepared from Fe(Ⅲ)-ethylenediamine-N,N'-diacetic acid (FeEN3+)/K3Fe(CN)6 solution, the mid-peak potential was 0.156 V in 0.1 M KNO3 and it was found that potassium ion migrates into or out of the film during the electrolysis. These films were shown to be electrochromic. These films exhibited smaller peak separation than those formed from Fe(Ⅲ)-tartaric acid (FeTA3+)/K3Fe(CN)6 system. The diffusion coefficient of Fe(CN)63-/4- redox couple, evaluated using the fabricated Au rotating disc electrode(rde) previously reported, was in good agreement with the existing data. Two experimental procedures, including the voltammetry at relatively low scan rates and the rde study, have been used in order to characterize the electrode kinetics. The electrode kinetics of some redox couples (FeEN2+-FeEN3+ and FeTA2+-FeTA3+) on both PB-modified thin films and bare Au electrode were studied using a Au rde. In all cases the rate constants of electron transfer obtained with the PB-modified film electrodes were only slightly less than those obtained for the same reaction on bare Au disc electrodes. The conductivities, as determined from the slopes of the i-V curves for a ca. 1 mm sample for dried PB-modified potassium-rich and deficient bulk samples pressed between graphite electrodes, were 6.21 × 10-7 and 2.03 × 10-7(Ω·cm)-1, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.5
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• pp.199-204
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• 2022

A new three-dimensional Gd-MOF, [Gd(p-XBP4)₄(H₂O)]·W(CN)₈; (1; p-XBP4 = N,N'-p-phenylenedimethylenbis (pyridin-4-one)) has been synthesized by slow-evaporation and its crystal structure was characterized by single-crystal X-ray diffraction (SCXRD) analysis. For each Gd^III ion, there are seven coordination sites, which are occupied by six oxygen atoms of six p-XBP4 ligands and one oxygen atom from the water molecule. The [W(CN)₈]^3- anion exists for charge balance with cationic framework. The Gd^II ions are interconnected by the p-XBP4 ligand to form the three-dimensional structure. Considering the magnetic property of lanthanide ions, magnetic studies of Gd-MOF were investigated by direct-current (DC) magnetic susceptibilities measurements.