• Analytical Science and Technology
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• v.9 no.4
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• pp.336-344
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• 1996

The extraction of trace cobalt, copper, nickel, cadmium, lead and zinc in urine samples of organic and alkali metal matrix into chloroform by the complex with a dithizone was studied for graphite furnace AAS determination. Various experimental conditions such as the pretreatment of urine, the pH of sample solution, and dithizone concentration in a solvent were optimized for the effective extraction, and some essential conditions were also studied for the back-extraction and digestion as well. All organic materials in 100 mL urine were destructed by the digestion with conc. $HNO_3$ 30 mL and 30% $H_2O_2$ 50 mL. Here, $H_2O_2$ was added dropwise with each 5.0 mL, serially. Analytes were extracted into 15.0 mL chloroform of 0.1% dithizone from the digested urine at pH 8.0 by shaking for 90 minutes. The pH was adjusted with a commercial buffer solution. Among analytes, cadmium, lead and zinc were back-extracted to 10.00 mL of 0.2 M $HNO_3$ from the solvent for the determination, and after the organic solvent was evaporated, others were dissolved with $HNO_3-H_2O_2$ and diluted to 10.00 mL with a deionized water. Synthetic digested urines were used to obtain optimum conditions and to plot calibration-eurves. Average recoveries of 77 to 109% for each element were obtained in sample solutions in which given amounts of analytes were added, and detection limits were Cd 0.09, Pb 0.59, Zn 0.18, Co 0.24, Cu 1.3 and Ni 1.7 ng/mL, respectively. It was concluded that this method could be applied for the determination of heavy elements in urine samples without any interferences of organic materials and major alkaline elements.

• Conservation Science in Museum
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• v.24
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• pp.1-16
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• 2020

This paper presents the process of re-conservation and the results of research on the production method of the Iron Sword with Ring Pommel with Three-Pointed Leaf Decoration, one of the excavation findings from Tomb No. 55 in the Dalseong Ancient Tomb Complex in Daegu. This iron sword is a double weapon with two large swords housed within a single sheath. Four smaller swords are attached to the surface of the sheath, two on the upper portion and the other two below. It is the only such two-in-one weapon excavated intact thus far from an ancient Korean tomb. The records show that it underwent conservation treatment twice in the past. In this study, it was subjected to conservation treatment again to replace the stiffener in some cracking areas, and its material, composition, and production method were analyzed by CT, XRF analysis, and stereoscopic microscopy. The sword is mainly made of copper, but the golden component contains both gold and mercury, which suggests that the copper was plated in gold using mercury amalgamation. The examination of the production methods indicates that it was intended more to demonstrate the authority of its owner rather than to serve any practical use. The two upper small swords on the sheath were made in the same manner as the main swords, and the two small lower swords were cut from a single metal sheet. The sheath was made by cutting two metal sheets. Supports were used to attach the two small swords to the upper portion of the sheath, while the lower portion of the sheath was slit to allow the other two small swords to be inserted into it. The ring pommels of the main swords have a three-pointed leaf decoration. As for the other designs, the handle of the main sword features a series of semicircles, the decorative bands on the sheath have waves in dots, and the fish tail of the sheath shows diagonal lines of dots.

• Asian Journal of Atmospheric Environment
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• v.7 no.2
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• pp.120-128
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• 2013

The concentration and composition of particulate matter (PM) in the atmosphere can directly reflect the environmental pollution. The atmospheric pollution in some Cameroonian cities is increasing with the industrial development and urbanization. Air pollution is inherently complex, containing PM of varied size and composition. This PM exists as a dynamic cloud interacting with sunlight and is modified by the meteorology. The reflectometer and the EDXRF spectrometry are applied to determine the concentration of some specific elements at four sites in the city of Yaound$\acute{e}$. The particular aim of the present work is to put in place data base on air pollution in urban area and elaborate regulations on the emissions issued to industrial and vehicle activities. This study provides an overview of the concentration of black carbon and some specific elements in the air, which have impacts on human health. The measurement was done by distinguishing the size of particle. So that, the particle with aerodynamic diameter between $2.5-10{\mu}m$ (so-called coarse particle) and aerodynamic diameter < $2.5{\mu}m$ (so-called fine particle) were considered to obtain more information about levels of the inhalable fraction of the location. The results obtained in four locations of the city of Yaound$\acute{e}$ show that the black carbon concentration is very considerable, the element sulfur is a major pollutant and the concentration of fine particle is very greater. The results obtained of fine and coarse filters range from $5-17{\mu}g/m^3$ and $10-18{\mu}g/m^3$ for the black carbon. S, Cu, Zn, Pb, Cd, As, Se and Hg are the specific findings of this work. The pollutants with a greater concentration are S, Pb, and Zn. These later seem to be non-uniformly, non-regular in some location and high compared to other countries. This work allows us to make a potential relation between pollutants and emission sources. In this framework, some suggestions have been proposed to reduce emissions for an improvement of the air quality in the environment and thus, the one of the city of Yaound$\acute{e}$.

• KSBB Journal
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• v.19 no.4
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• pp.250-256
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• 2004

In this work we have cultivated several B. cereus strains in a complex LB medium in order to study the production of phospholipase C (PLC), and among them B. cereus 318 showed the highest productivity of PLC. Some components, i.e., 5 g/L glucose, 5 g/L yeast extract, 5 g/L peptone, 0.5∼1.0 g/L K$_2$HPO$_4$, 0.02∼0.04 g/L ZnSO$_4$$.$7H$_2$O and 3 g/L NaHCO$_3$ were found to be optimal for the high production of PLC by B. cereus 318. Optimal culture temperature and pH were found to be 30$^{\circ}C$ and pH 7.5 for the PLC production, respectively. Optimum reaction temperature and pH of the PLC produced by B. cereus 11 and 318 were 45$^{\circ}C$ and pH 4.0, while they were 50$^{\circ}C$ and pH 7.0 for the PLC by B. cereus 559. The PLC produced by B. cereus was activated by Mn$\^$2+/, Co$\^$2+/ and dimethyl sulfoxide (DMSO), but its activity was inhibited by Cu$\^$2+/ and partially by glycerol, isopropanol and sodium dodecyl sulfate (SDS).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.1-8
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• 2010

Natural convection heat transfer rates in a vertical pipe were measured for $Gr_H$ number from 2.1x$10^6$ to 1.2x$10^9$. Using the analogy concept, heat transfer experiments were replaced by mass transfer experiments. A cupric acid - copper sulfate ($H_2SO_4-CuSO_4$) electroplating system was adopted as the mass transfer system and the mass transfer rates were measured. Comparison of the results with the existing laminar and turbulent natural convection heat transfer correlations on a vertical plate showed very good agreements except for the high $Gr_H$ case, where the boundary layer inside the vertical pipe interferes. The agreements showed the usefulness of the analogy experiment method. Using 3 different anode size and 6 different geometrical configurations, the effects of the anode size and position were explored. As expected, the anode size and position do not affect the limiting currents for most cases. These results will be used as the experimental background for the positioning and sizing of the anodes for a more complex experiment.

• Parasites, Hosts and Diseases
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• v.36 no.2
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• pp.69-80
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• 1998

Subgenus classification of Acanthcmoeba remains uncertain. Twenty-three reference strains of Acanthnmoeba including 18 (neo)type-strains were subjected for classification at the subgenus level by riboprinting, PCR/RFLP analysis of 185 rRNA gene (rDNA) . On the dendrogram reconstructed on the basis of riboprint analyses, two type- strains (A. astronwxis and A. tubinshi) of morphological group 1 diverged early from the other strains and were quite distinct from each other. Four type-strains of morphological group 3. A. culbertsoni, A. polestinensis, A. healyi were considered taxonomically valid, but A. pustulosn was regarded as an invalid synonym of A. pclestinensis. Strains of morphological group 2 were classified into 6 subgroups. Among them, A. giulni which has an intron in its 185 rDNA was the most divergent from the remaining strains. Acanthcmoebc ccstellanii Castellani, A. quinc Vil3, A. Iugdunensis L3a. A. poIyphage Jones, A. trinngularis SH621, and A. cqstellanii Ma strains belonged to a subgroup, A. castellanii complex. However, A. quinc and A. Lugnunensis were regarded as synonyms of A. ccstellanii. The Chang strain could be regarded as A. hatchetti. Acanthcmoebo nauritaniensis, A. niuionensis, A. paranivionensis could be considered as synonyms of A. rhwsodes. Neff strain was regarded as A. polyphage rather than as A. castellanii. It is likely that riboprinting can be applied for rapid identification of Acnnthcmoebc isolated from the clinical specimens and environments.

• Economic and Environmental Geology
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• v.42 no.1
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• pp.1-8
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• 2009

The Haman mineralized area is located within the Cretaceous Gyeongsang Basin along the southeastern part of the Korean peninsula. Almost all occurrences in the Haman area are representative of copper-bearing polymetallic hydrothermal vein-type mineralization. Within the area are a number of fissure-filling hydrothermal veins which contain tourmaline, quartz and carbonates with Fe-oxide, base-metal sulfide and sulfosalt minerals. The Gunbuk, Jeilgunbuk and Haman mines are each located on such veins. The ore and gangue mineral paragenesis can be divided into three distinct stages: Stage I, tourmaline + quartz + Fe-Cu ore mineralization; Stage II, quartz + sulfides + sulfosalts + carbonates; Stage III, barren calcite. Equilibrium thermodynamic data combined with mineral paragenesis indicate that copper minerals precipitated mainly within a temperature range of $350^{\circ}C$ to $250^{\circ}C$. During early mineralization at $350^{\circ}C$, significant amounts of copper ($10^3$ to $10^2\;ppm$) could be dissolved in weakly acid NaCl solutions. For late mineralization at $250^{\circ}C$, about $10^0$ to $10^{-1}\;ppm$ copper could be dissolved. Equilibrium thermodynamic interpretation indicates that the copper in the Haman-Gunbuk systems could have been transported as a chloride complex and the copper precipitation occurred as a result of cooling accompanied by changes in the geochemical environments ($fs_2$, $fo_2$, pH, etc.) resulting in decrease of solubility of copper chloride complexes.

• Economic and Environmental Geology
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• v.32 no.6
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• pp.611-631
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• 1999

Enviromental geochemisty and heary metal contamination at the Kongjueil mine creek were underaken on the basis of physicohemical properties and mineralogy for various kinds of water (surface, mine and ground water),soil, precipitate and sediment collected of April and December in 1998. Hydrgeochemical composition of the water samples are characterized by relatively significant enricant of Ca+Na, alkiali ions $NO_3$ and Cl inground and surfore water, wheras the mine waters are relatively eneripheral water of the mining creek have the characteristics of the (Ca+Mg)-$(HCO_3+SO_4)$type. The pH of the mine water is high acidity (3.24)and high EC (613$\mu$S/cm)compared with those of surface and ground water. The range of $\delta$D and $\delta^{18}O$ values (relative to SMOW) in the waters are shpwn in -50.2 to -61.6% and -7.0 to -8.6$\textperthousand$(d value=5.8 to 8.7). Using computer program, saturation index of albite, calcite, dolomite in mine water are nearly saturated. The gibbiste, kaolinite and smectite are superaturated in the surface and ground water, respectively. Calculated water-mineral reaction and stabilities suggest that weathing of silicate minerals may be stable kaolinite owing to the continuous water-rock reaction. Geochemical modeling showed that mostly toxic heavy metals may exist larfely in the from of metal-sulfate $(MSO_4\;^2)$and free metal $(M^{2+})$ in nmine water. These metals in the ground and surface water could be formed of $CO_3$ and OH complex ions. The average enrichment indices of water samples are 2.72 of the groundwater, 2.26 of the surface water and 14.15 of the acid mine water, normalizing by surface water composition at the non-mining creek, repectively. Characteristics of some major, minor and rate earth elements (Al/Na, K/Na, V/Ni, Cr/V, Ni/Co, La/Ce, Th/Yb, $La_N/Yb_N$, Co/Th, La/Sc and Sc/Th) in soil and sediment are revealed a narrow range and homogeneous compositions may be explained by acidic to intermediate igneous rocks. And these suggested that sediment source of host granitic gneiss colud be due to rocks of high grade metamorphism originated by sedimentary rocks. Maximum concentrations of environmentally toxic elements in sediment and soil are Fe=53.80 wt.% As=660, Cd=4, Cr=175, Cu=158, Mn=1010, Pb=2933, Sb=4 and Zn=3740 ppm, and extremely high concentrations are found are found in the subsurface soil near the ore dump and precipitates. Normalizing by composition of host granitic gneiss, the average enerichment indices are 3.72 of the sediments, 3.48 of the soils, 10.40 of the precipitates of acid mine drainage and 6.25 of the soils near the main adit. The level of enerichment was very severe in mining drainage sediments, while it was not so great in the soils. mineral composition of soil and sediment near the mining area were partly variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. reddish variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. Reddish brown precipitation mineral in the acid mine drainage identifies by schwertmanite. From the separated mineralgy, soil and sediment are composed of some pyrite, arsenopyite, chalcopyrite, sphalerite, galena, malachite, goethite and various kinds of hydroxied minerals.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.102-117
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• 2009

This study was carried out to investigate the extent to which benthic environment of Ulsan Bay was disturbed by organic materials and trace metals from the megacity and industrial complex. Field survey for benthic environment and macroinvertebrate community was seasonally conducted from February to November 2006 at nine stations covering the inside and outside of the bay. TOC was on average 1.7% while four (As, Cu, Pb, Zn) out of seven trace metals measured exceeded the Effects Range Low (ERL) in most of the stations. Total number of species sampled was 199 and mean density was 4,578 ind./$m^2$, both of which were greatly dominated by the polychaetes. Dominant species were Aphelochaeta monilaris (22.6%), Ruditapes philippinarum (17.1%), Magelona japonica (12.2%), Lumbrineris longifolia (9.9%) and their distribution was ruled by the difference in the benthic environmental condition of each station. From the multivariate analyses, four stational groups were identified: northern part of the bay, middle and lower part of the bay, the intersection of Taewha River and Gosa stream and outside of the bay. As a result, the community heterogeneity of inner bay was much more greater than that of outer bay. SIMPER analysis showed that four groups were represented by R. philippinarum-Capitella capitata, A. monilaris-Balanoglossus carnosus, Sinocorophium sinensis-Cyathura higoensis and M. japonica-Ampharete arctica, respectively. Spatio-temporal changes of macroinvertebrate communities in Ulsan Bay were closely related to those of depth, mean grain size and organic content, and Zn was also a meaningful factor in that context.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.366-370
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• 1989

A new macrocyclic ligand 1,15,18-triaza-3,4;12,13-dibenzo-5,8,11-cycloeicosane (NdienOdien$H_4$ = $N_3O_3$) has been synthesized and identified by element analysis, NMR and IR spectrophotometry. Stepwise protonation constants of ligand are determined by potentiometry in 95% methanol solution(I = 0.1 mol $dm^{-3}$, $Me_4$NCl). log $K_1$;log $K_2$;log $K_3$ = 9.1;8.1;3.6.The kinetics of the acid-promoted dissociation reactions of complex cations of nickel(II) and copper(III) with NdienOdien and NdienOen macrocyclic ligands having, respectively, 17 and 20 ring members, have been studied spectrophotometrically in HCl$O_4$ NaCl$O_4$ aqueous solutions. From the temperature effect on kinetic constant ($k_{obs}$), the parameters of activation(${\Delta}H^{\neq}$, ${\Delta}S^{\neq}$) of dissociation reaction for $ML^{2+}$ with $H^+$ ion have been determined. We have proposed the possible mechanism of the reaction from the data obtained.