• Title/Summary/Keyword: Co(II)

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Studies on Partition and Extraction Equilibria of Metal-Dithiocarbamate Complexes(II). Metal Complexes of Ammonium Pyrrolidine Dithiocarbamate (Dithiocarbamate 금속착물의 분배 및 추출평형(제2보). Ammonium Pyrrolidine Dithiocarbamate의 금속착물)

  • Lee, Jong-Sun;Choi, Jong-Moon;Choi, Hee-Seon;Kim, Young-Sang
    • Analytical Science and Technology
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    • v.8 no.3
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    • pp.321-334
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    • 1995
  • Basic studies for the effective extraction of ammonium pyrrolidine dithiocarbamate(APDC) complexes of Co(II), Ni(II) and Cu(II) into a solvent have been performed. The maximum distribution ratio was appeared (log D=1.3543) at pH 2.0 and the partition coefficient was 2.489 in the extraction of $4{\times}10^{-5}M$ APDC itself into chloroform. From the UV/visible spectra of metal-chelates in aqueous and organic solutions, the pH to form stable 1:2 metal-ligand complexes were Co(II):5.0, Ni(II):8.0 and Cu(II):8.0, respectively and only 1 minute was enough to be partitioned into the chloroform. Besides, the partition and extraction equilibria of the complexes were investigated by back-extracting $10.0{\mu}g/ml$ metal-chelates from the solvent into an aqueous solution beacuse of their slight solubilities in the aqueous solution. The distribution coefficients and extractabilities were as follows : at pH 6.5~8.5 of the aqueous solution, log D=2.834 : E(%)=99.9% for $Co(PDC)_2$, at pH 11, log D=5.699 E%=100 for $Ni( PDC)_2$, and at pH 6.0, log D=2.025 : E(%)=99.1% for $Cu(PDC)_2$. And the extraction and formation constants were log $K_{ex}=9.671$ : log ${\beta}_2=6.938$ for $Co(PDC)_2$, log $K_{ex}=9.646$ : log ${\beta}_2=7.071$ for $Ni( PDC)_2$, and log $K_{ex}=9.074$ : log ${\beta}_2=7.049$ for $Cu(PDC)_2$, respectively. From these results, an optimum extraction procedure can be constructed for the separative concentration of trace metallic ions, and the quantitative determination of them in advanced materials and environmental samples will be expected without any influence of sample matrixes.

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Preparation of cobalt oxide(Co3O4·CoO) ultra fine particles using cobalt(II) chloride hexahydrate and crystalline cellulose as a starting materials (Cobalt(II) chloride hexahydrate와 결정성 셀룰로오스를 출발물질로 사용한 산화코발트(Co3O4·CoO) 초미세입자의 합성)

  • Soo-Jong Kim
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.587-592
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    • 2023
  • Cobalt oxide (Co3O4·CoO) ultra fine particles were synthesized by liquid phase precursor method. cobalt(II) chloride hexahydrate (CoCl2·6H2O) was as a starting material. A plant-derived crystalline cellulose was used as impregnating materials. A impregnated precursor was calcined at a temperature of 350 to 900℃ to obtain cobalt oxide particles having a particle size of 1 to 10㎛. The crystallization process and morphology according to the calcination temperature were examined, and the properties of the synthesized powder were evaluated using SEM and XRD. It was confirmed that a crystal phase of Co3O4 began to form around 350℃ and crystal growth occurred up to 900℃. At a temperature above 500℃, the Co3O4 crystal was changed to another crystal phase CoO.

Spectrophotometric, pH-metric and Conductometric Studies on Some 3-Arylhydrazone Derivatives of (2-Thenoyl) Ethylpyruvate) (2-Thenoyl Ethylpyruvate의 몇 가지 3-Arylhydrazone 유도체에 대한 분광광도법, pH 및 전도도법 연구)

  • El-Dossoki, F. I.;El-Seify, F. A.
    • Journal of the Korean Chemical Society
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    • v.50 no.2
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    • pp.99-106
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    • 2006
  • The electronic absorption spectra of [3-(2-thenoyl) 3-(p-NO2-phenylhydrazone) ethyl pyruvate] (I), p-Br (II) and p-CH3 (III) were studied in ethanol and the spectra comprise four absorption bands which assigned to the corresponding electronic transition. The pK values of these compounds have been determined spectrophotometrically and pH-metrically, the results shown that the interval range for color change of compound (I) is (8-10) similar to that of phenolphethalin indicator, indicating that this compound can be used as acid-base indicator. The successive stability constants of the compounds under study with some transition elements (Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO2(II), La(III) and Zr(IV) have been determined pH- metrically. Stoichiometric complexes with ratios 1:1 and 1:2 (M: L) were formed for all metals. The pK of the three derivatives and the values of the stability constant (logK) of the complexes have the order; III > II > I. Also conductometric titrations have been carried out and the results show that this titration can be used for determination of both the metal ion and the ligand concentrations by each others.

Electrical Behaviour of Some Phthalimide Derivatives and Their Complexes with Transition Metals

  • Mohamed Gamal Abd Ei Wahed;Kamel Ei Manakhly;Hamdy Hammad;Atiat Barakat
    • Bulletin of the Korean Chemical Society
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    • v.17 no.3
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    • pp.285-288
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    • 1996
  • The electrical conductivity of some phthalimide derivatives and their complexes with Co(II), Ni(II), Cu(II), or Zn(II) has been measured in the temperature range 290-435 K. Both the structure of phthalimide molecule and its complexes played an effective role in the conduction process. Conductometric titration and IR spectra were used to characterize the structure of studied samples.

Ecophysiology of Photosynthesis 1: Effects of Light Intensity and Intercellular $CO_2$ Pressure on Photosynthesis (광합성의 생리생태(1) - 광도와 엽육내 $CO_2$분압 변화에 대한 광합성 반응 -)

  • 김판기;이은주
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.3 no.2
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    • pp.126-133
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    • 2001
  • 녹색식물과 같이 독립영양생물이 빛에너지를 이용하여 $CO_2$와 물로 탄수화물을 만드는 일련의 반응을 광합성이라 한다. 그 일련의 반응 중에서(그림 1) 반응 I과 II는 틸라코이드(thylakoid)에서, 반응 III은 스트로마(stroma)에서, 반응 IV는 엽록체내와 세포질에서 일어나는 반응의 상호작용에 의하여 나타난다. 과거에는 반응 I과 II를 명반응, 반응 III과 IV를 암반응이라 부르기도 하였다.(중략)

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Off-Site Consequence Analysis for PWR and PHWR Types of Nuclear Power Plants Using MACCS II Code (MACCS II 코드를 이용한 국내 경수로 및 중수로형 원전의 소외결말분석)

  • Jeon, Ho-Jun;Chi, Moon-Goo;Hwang, Seok-Won
    • Journal of the Korean Society of Safety
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    • v.26 no.5
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    • pp.105-109
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    • 2011
  • Since a severe accident, which happens in low frequency, can cause serious damages, the interests in off-site consequence analysis for a nuclear power plant have been increased after Chernobyl, TMI and Fukushima accidents. Consequences, which are the effects on health and environment caused by released radioisotopes, are evaluated using MACCS II code based on the method of Level 3 PSA. To perform a consequence analysis for the reference plants, the input data of the code were generated such as meteorological data, population distribution, release fractions, and so on. Using these input data, acute and lifetime dose as an organ, CCDF for early fatalities and latent cancer fatalities, and average individual risk were analyzed by using MACCS II code in this study. These results might contribute to establishing accident management plan and quantitative health object.

Stable Isotope and Fluid Inclusion Studies of the Daebong Gold-silver Deposit, Republic of Korea (대봉 금-은광상에 대한 유체포유물 및 안정동위원소 연구)

  • 유봉철;이현구;김상중
    • Economic and Environmental Geology
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    • v.36 no.6
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    • pp.391-405
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    • 2003
  • The Daebong gold-silver deposit consists of mesothermal massive quartz veins thar are filling the fractures along fault shear (NE, NW) Bones within banded or granitic gneiss of Precambrian Gyeonggi massif. Based on vein mineralogy, ore textures and paragenesis, ore mineralization of this deposits is composed of massive white quartz vein(stage I) which was formed in the same stage by multiple episodes of fracturing and healing, and transparent quartz vein(stage II) which is separated by a major faulting event. Stage I is divided into the 3 substages. Ore minerals of each substages are as follows: 1) early stage I=magnetite, pyrrhotite, arsenopyrite, pyrite, sphalerite, chalcopyrite, 2) middle stage I=pyrrhotite, arsenopyrite, pyrite, marcasite, sphalerite, chalcopyrite, galena, electrum and 3) late stage I=pyrite, sphalerite, chalcopyrite, galena, electrum, argentite, respectively. Ore minerals of the stage II are composed of pyrite, sphalerite, chalcopyrite, galena and electrum. Systematic studies (petrography and microthermometry) of fluid inclusions in stage I and II quartz veins show fluids from contrasting physical-chemical conditions: 1) $H_2O-CO_2-CH_4-NaCl{\pm}N-2$ fluid(early stage I=homogenization temperature: 203∼3$88^{\circ}C$, pressure: 1082∼2092 bar, salinity: 0.6∼13.4 wt.%, middle stage I=homogenization temperature: 215∼28$0^{\circ}C$, salinity: 0.2∼2.8 wt.%) related to the stage I sulfide deposition, 2) $H_2O-NaCl{\pm}CO_2$ fluid (late stage I=homogenization temperature: 205∼2$88^{\circ}C$, pressure: 670 bar, salinity: 4.5∼6.7 wt.%, stage II=homogenization temperature: 201-3$58^{\circ}C$, salinity: 0.4-4.2 wt.%) related to the late stage I and II sulfide deposition. $H_2O-CO_2-CH_4-NaCl{\pm}N_2$ fluid of early stage I is evolved to $H_2O-NaCl{\pm}CO_2$ fluid represented by the $CO_2$ unmixing due to decrease in fluid pressure and is diluted and cooled by the mixing of deep circulated meteoric waters ($H_2O$-NaCl fluid) possibly related to uplift and unloading of the mineralizing suites. $H_2O-NaCl{\pm}CO_2$ fluid of stage II was hotter than that of late stage I and occurred partly unmixing, mainly dilution and cooling for sulfide deposition. Calculated sulfur isotope compositions ({\gamma}^{34}S_{H2S}$) of hydrothermal fluids (3.5∼7.9%o) indicate that ore sulfur was derived from mainly an igneous source and partly sulfur of host rock. Measured and calculated oxygen and hydrogen isotope compositions ({\gamma}^{18}O_{H_2O}$, {\gamma}$D) of ore fluids (stage I: 1.1∼9.0$\textperthousand$, -92∼-86{\textperthansand}$, stage II: 0.3{\textperthansand}$, -93{\textperthansand}$) and ribbon-banded structure (graphitic lamination) indicate that mesothermal auriferous fluids of Daebong deposit were two different origin and their evolution. 1) Fluids of this deposit were likely mixtures of $H_2O$-rich, isotopically less evolved meteoric water and magmatic fluids and 2) were likely mixtures of $H_2O$-rich. isotopically heavier $\delta$D meteoric water and magmaticmetamorphic fluids.

The Prevalence Study of TMD and the Associated Factors in Korean Malocclusion Patients (한국인 부정교합자의 측두하악장애(TMD) 유병율과 그 기여요인에 관한 연구)

  • Kim, Myung-Hee;Nahm, Dong-Seok
    • The korean journal of orthodontics
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    • v.27 no.4 s.63
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    • pp.523-538
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    • 1997
  • In order to investigate TMD prevalence in malocclusion patients and to study its relationship with occlusal factors, 205 malocclusion patients (M67, F138, 6Y1M-46Y8M) were examined. The following examinations were carried out, Questionnaire personal history, TMD symptoms, and the associated factors Clinical examination : TMJ sound and maximum mouth opening Orthopantomogram : condyle abnormalities, length of Co'-Inc' and Co'-Go', ratio Co'- Inc'/ Co'-Go', and depth of antegonial notch Transcranial view limitation of anterior movement of condyle Model Angle classification, overjet, overbite, midline discrepancy, missing of posterior teeth, posterior crossbite, attrition of palatal cusp of maxillary molars, crowding/spacing The results could be summarized as follows, 1. The prevalence of TMD showed that Helkimo Anamestic Inder(Ai) 0 was $46.8\%$, Ai I was $22.0\%$, Ai II was $31.2\%$ and subjective symptoms increased with aging (p<0.001) and were frequent in females (p<0.05). 2. Flattening ($4.4\%$) was the most frequent condyle abnormality on Orthopantomogram, and $8.3\%$ of subjects showed some abnormalities on Orthopantomogram. 3. The cases with neck and shoulder pain (p<0.001), clenching, lip biting (p<0.01), and headache (p<0.05) showed higher scores of Ai. 4. Angle class II showed high frequency of condylar abnormalities on Orthopantomogram, and subjects whose palatal cusp of maxillary molars had been attrided had the tendency to show high hi scores (p<0.05). The other occlusal factors had nothing to do with the symptoms of TMD. 5. In the cases that 1)the value of Co'-Inc', Co'-Go' or Co'-Inc'/Co'-Go' were low or 2)the differences of Co'-Go' or Co'-Inc'/Co'-Go' between the right and the left were large, condylar abnormalities were frequently obserbed on Orthopantomogram.

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Electrochemical Propertics and Oxidation Reaction of Hydrazobenzene by Oxygen Adducted Tetradentate Schiff Base Cobalt(II)(3MeOSED) Activated Catalyst in Aprotic Solvents(I) (비수용매에서 산소첨가된 네자리 Schiff Base Cobalt(II)(3MeOSED) 활성촉매에 의한 Hydrazobenzene의 산화반응과 전기화학적 성질 (제 1 보))

  • Ki-Hyung Chjo;Yong-Kook Choi;Sang-Bock Kim
    • Journal of the Korean Chemical Society
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    • v.36 no.2
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    • pp.261-272
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    • 1992
  • Tetradentate Schiff base Cobalt(II)(3MeOSED)$(H_2O)_2$ complexe was synthesized and allowed to react with dry oxygen to form oxygen adducts of Cobalt(III) complexes such as ${\mu}$-peroxo type [Co(III)(3MeOSED)(DMF)]$_2O_2$ and [Co(III)(3MeOSED)(DMSO)]$_2O_2$in DMF and DMSO or superoxo type [Co(III)(3MeOSED)(Py)]$O_2$ in pyridine. The oxygen adducted complex was investigated by cyclic voltammetry and DPP method with glassy carbon electrode in 0.1M TEAP-DMF (-DMSO,-Py) as supporting electrolyte solution. As a result the reduction reaction process occurred to four steps including prewave Of $O_2^-$in 1 : 1 oxygen adducted superoxo type [Co(III)(3MeOSED)(Py)]$O_2$complex and three steps not including prewave of $O_2^-$ in 1 : 2 oxygen adducted ${\mu}$-peroxo type [Co(III)-(3MeOSED)(DMF)]$_2O_2$ and [Co(III)(3MeOSED)(DMSO)]$_2O_2$. A superoxo type [Co(III)(3MeOSED)(L)]$O_2\;(L: CH_3OH)$ was generated with oxygen in methanol. Selectively oxidized hydrazobenzene $(H_2AB)$ to trans-azobenzene(t-AB) and the rate constant k for oxidation reaction of the following equation is $(2.96 {\pm} 0.2)$${\times}$ $10^{-1}$M/sec. $H_2AB$ + Co (II)(3MeOSED)$(L_2)+O_2\;{\rightleftarrow^K}$ [Co(III)(3MeOSED)(L)]$O_2{\cdot}H_2AB{\longrightarrow^K}$ Co(II(3MeOSED)$(L)_2$+t-AB+$H_2O_2 $.

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CO OBSERVATIONS OF A HIGH LATITUDE HII REGION S73 WITH HIGH RESOLUTION AUTOCORRELATOR

  • LEE YOUNGUNG;CHUNG H.S.;KIM H.R.
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.187-188
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    • 1996
  • We have mapped $1 deg^2$ region toward a high latitude HII region S73 (l, b) = ($37^{\circ}.69$, $44^{\circ}.55$) and associated molecular cloud in $^{12}CO$ J = 1 - 0, and $^{13}CO$ J = 1 - 0, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. A high resolution autocorrelator is used to resolve extremely narrow CO linewidths (FWHP < 1 km/s) of the molecular cloud. Though the linewidths are very narrow, it is found that there is systematic velocity gradient in the molecular gas associated with the H II region. Both of $^{12}CO$ and $^{13}CO$ averaged spectra are non-gaussian, and there are obvious blue wings in the spectra. It is remarkable that the linewidths at the blueshifted region are broader than those of the rest of the cloud. The CO emission does match well with the dust emission.

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