• Journal of the Korean Society of Marine Environment & Safety
• /
• v.19 no.6
• /
• pp.570-581
• /
• 2013

To improve productivity of aquaculture animals with management of culturing grounds, survey of mariculture management area in Ongjin-gun about water quality and sedimentary environment had been conducted on June, August and November in 2011. Water temperature in surface and bottom waters ranged from 9.49 to $24.14^{\circ}C$. Salinity and dissolved oxygen concentrations were in the range of 23.19~31.49 and 5.48~9.36 mg/L, respectively, depending on the variation of water temperature. The average concentration of COD was 1.57 mg/L and the concentrations of DIN and DIP showed entirely low level. As the result of grain size analysis, sand(56.66 %) and silt(34.60 %) were predominated. The Mz of sediment showed a variation of 2.59 to $6.62{\O}$ and sorting appeared to be poorly sorted. The concentrations of COD and IL in surface sediment ranged from 1.00 to $11.03mg/g{\cdot}dry$ and 0.72 to 5.29 %, respectively, which showed relatively good positive correlations. On the environmental assessment of trace metals in surface sediment, geoaccumulation index ($I_{geo}$) class indicated that sediments were not contaminated by most of metallic elements except Cr and As. Our result implies that this study area showed good water quality and sediments were not polluted by organic matters and metallic elements.

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

• Korean Journal of Mineralogy and Petrology
• /
• v.33 no.4
• /
• pp.307-324
• /
• 2020

Major and trace elements, and Sr, Nd, isotopic composition analysis have been carried out on the Miocene basalt (Huangsongpu basalt, 20 Ma) 25 km to northeast from the Mt. Baekdu. The basalt has Na2O+K2O=3.5~4.7 wt.%, and MgO=9.9~11.1 wt.%, containing Mg-rich olivine (Mg#=75~86), clinopyroxene (Mg#=72~85) and Ca-rich plagioclase micro-phenocrysts. These data suggest that the basalt belongs to the alkaline magma series with a primitive nature, crystallized at a near-liquidus. The basalt is also characterized by high Cr (394~479 ppm) and Ni (389~519 ppm) contents, Nb-Ta enrichment anomalies and OIB-like trace elements patterns, displaying identical signatures to those of typical intraplate magmas. The rare earth element (REE) patterns of the basalt and high (Gd/Yb)sample/(Gd/Yb)PM ratio (=2.8~3.5) suggest the parental magma was derived from relatively low-degree (3~5%) partial melting of garnet peridotite. The 143Nd/144Nd and 87Sr/86Sr composition of the basalt are higher than those of BSE. The high 87Sr/86Sr (= ~0.7058) ratio of the basalt indicates a contribution of recycled ancient oceanic crust or continental crust on the Pacific slab suggesting that the Huangsongpu basalt was generated from metasomatized mantle.

• The Korean Journal of Malacology
• /
• v.24 no.3
• /
• pp.243-251
• /
• 2008

Analyses of UV-Vis spectrum and reflectance are useful tools to identify pearls of which color was naturally made or chemically changed. Contents of some trace elements of pearls by using ED-XRF may give us the information that the pearls were originated from marine shells or freshwater shells, and may give us whether the pearls were chemically treated or not. Three types of chemically untreated pearls, freshwater cultured, Akoya cultured and Tahitian cultured, were treated with silver nitrate. UV-Vis absorbance spectrum of Ag was changed after treatment, and reflectance of pearls was decreased. Absorbance of natural black colored Tahitian cultured pearls at 400, 500 and 700 nm was observed. Natural black colored freshwater cultured pearls showed two characteristic absorption patterns in UV-Vis spectra at 380-400, 480-500 nm. Unlike naturally black colored Tahitian cultured pearls, the absorption spectrum at 700 nm could not be found from black freshwater cultured pearls. Manganese was not detected in the pearls from marine shells, and strontium content of the pearls from marine cultured shells was higher than that from freshwater cultured shells. According to ED-XRF analysis, Ag contents of silver nitrate treated pearls increased as more time passed, because silver ion invaded to nacre layer of the pearls. Since Ag content of the black pearls known as untreated ranged under 0.1%, analysis of Ag content may used to distinguish the black pearls are treated or not in marketplace.

• Economic and Environmental Geology
• /
• v.12 no.4
• /
• pp.181-195
• /
• 1979

The Nambu orebodies of the Okbang tungsten mine are hosted in the Precambrian amphibolite and Weonnam formation. These orebodies can be classified into two types; The scheelite-bearing ore vein occurring in the amphibolite (the Nambu 1, 2 adits) and tungsten-bearing quartz vein along the contact between the amphibolite and the Weonnam formation (the Young-ho, -1, -2, -3 levels). The scheelite-bearing ore vein in the amphilbolite is discontinuous, narrow, and highly irregular in geometry, occurring only within the amphibolite with which of the vein is graduational. Based on these feature of the mode of occurrence, the origin of this ore type might be attributed to a potential segregation of tungsten ore fluid in situ from hornblenditic basic magma of the host rock. Tungsten-bearing quartz vein, however, is considered to have deposited along the N30-60E trending fractures as a later hypothermal vein after the hornblendite was emplaced. The principal ore mineral is scheelite with minor amount of wolframite, and the gangue minerals are quartz, and small amounts of fluorite, pyrrhotite, chalcopyrite and calcite. Fluid inclusion study of minerals from the Nambu orebody reveals that the fluids in fluorite of the scheelite-bearning ore vein attained a temperature range of $208{\sim}256^{\circ}C$ and those in quartz from the tungsten-bearing quartz vein a temperature range of $220{\sim}357^{\circ}C$. The real formation temperatures can be somewhat higher than filling temperatures, if pressure correction is made. Chemical analysis of 8 amphibolitc samples on major and some trace elements indicate that the amphibolite is igneous origin. On a Niggli diagram (al-alk)versus c, the analytical values are plotted on an igneous field, and on a Niggli diagram mg versus c they follow a karroo igneous trend line. According to the Ba, Cr, and Ni versus Niggli mg plots suggested by Leake (1964), Okbang amphibolite fall outside a pelitic field and compare favorably with his plots form ortho-amphibolites. Analitical values of $MoO_3$ of 8 samples of scheelite minerals from the Nambu orebody indicate that the tungsten-bearing quartz vein (type n) of Nambu orebody shows a range from 1. 69% to 4.38% which is higher than 0.94%~3.25% $MoO_3$ for the scheelite-bearing ore vein (type I). This fact indicates that the type II was deposited in a lower $fO_2/higher$ $fO_2$ environment and under lower temperature than the type I. Analysis of major components $WO_3$, MnO, and FeO of 6 samples of wolframite from the type II veins revealed that they contain 73.35~76.2% $WO_3$, 7.94~11.63% MnO, and 10.53~14.82% FeO. MnO/FeO ratios of wolframite shows the range of 0.85~1.17 which suggests a slightly higher temperature type of deposits than other major tungsten deposits in the country.

• Journal of the Mineralogical Society of Korea
• /
• v.22 no.2
• /
• pp.97-106
• /
• 2009

It is known that the natural amethyst is changed to citrine after heat treatment. However, when all amethyst samples from Zambia were heat-treated in the temperature range of $350{\sim}380^{\circ}C$ for 1 hour, the result was that five out of eight samples were changed to citrine and all the rest of samples became rock crystal quartz. These differences in the color appearance seem to be influenced by the original colors contained in the amethyst before the heat treatment. The amethyst containing yellow color changed to citrine and the amethyst without containing yellow color changed to rock crystal quartz after the heat treatment. The results compared after the instrumental analysis on the difference of color change, it showed the differences of peak intensity in 3,400 $cm^{-1}$ and the existence and non-existence of peak at the range of 5,200${\sim}$5,400 $cm^{-1}$ in FTIR. It revealed the difference in the quantity of Cr which is a trace element in the WD-XRF analysis. The identical result in the FTIR spectra before and after the heat treatment reveals that the heat treatment did not cause any change in the main composing elements or crystal structure.

• Journal of Food Hygiene and Safety
• /
• v.39 no.2
• /
• pp.83-94
• /
• 2024

The proportion of plant-based meat alternative (PBMA) consumers has recently increased in Korea. This is due to several reasons including protecting the environment, satisfying preferences, maintaining health, and improving eating habits. Accordingly, many companies produce and sell alternative meat using various materials. Alternative meats are classified into plant (such as soybeans and wheat), seaweed, insect, and cultured meats, depending on the raw materials used in manufacturing. PBMA is sold after undergoing processes such as grinding, seasoning, and molding. Therefore, monitoring the presence of any hazardous elements during this process is essential. Accordingly, in this study, we analyzed the harmful components of nine domestically distributed PBMA that are most easily accessible to consumers. After extracting fat from the samples and analyzing the rancidity level, samples F, G, and I were highly rancid. Trace amounts of aflatoxin were detected in samples A and B, but confirmed to be within the range. Cd and Pb were not detected in any sample. We hope that this study will help establish methods to ensure the safety of domestically sold PBMA.

• Archives of Plastic Surgery
• /
• v.34 no.5
• /
• pp.543-550
• /
• 2007

Purpose: Diabetic foot ulcer is a representative disease of chronic would with multiple defects of wound healing factors. Many nutrition factors have been known to be essential for wound healing, but objective data are lacking. The purpose of this study is to determine those factors essential for wound healing, and to find out which of those factors are lacking in diabetic foot ulcer patients through this pilot study. Methods: We studied 100 patients who visited our clinic from March 2005 to February 2006 for treatment of diabetic foot ulcers with a duration of more than 6 weeks. We checked serum levels of protein, albumin, vitamin A, C, E, iron, magnesium, zinc, copper and hemoglobin by drawing 23cc blood after 8 hours of fasting. Protein, albumin, iron, magnesium levels were measured by colorimetry; hemoglobin levels were measured by auto analysis. Vitamin levels were measured by high performance liquid chromatography (HPLC), copper and zinc levels were measured by Inductively coupled plasma (ICP). They were compared with normal values. The patients were divided by transcutaneous oxygen pressure levels, age and sex to study the effects of these parameters. Results: 76% and 61% of patients had within-normal range serum protein and albumin levels, respectively. Among vitamins, only the level of vitamin C was low in 55% of the patients. Levels of vitamin A, E were normal or high in 93% and 100% of patients. As for trace elements, levels of iron and zinc were low in 63% and 60% of patients, but levels of magnesium and copper were usually normal or high. Levels of vitamin C, iron and zinc were lower in the low-transcutaneous oxygen pressure group. There were no definite differences according to age and sex. Conclusion: Serum levels of Hb, vitamin C, iron, zinc were low in most diabetic foot ulcer patients. The deficit was very severe in the low-transcutaneous oxygen pressure group.

• Journal of the Korean Chemical Society
• /
• v.63 no.6
• /
• pp.453-458
• /
• 2019

Synthesis of ZnCo₂O₃ oxide is performed by sol-gel method via nitrate-citrate route. Powder X-ray diffraction (XRD) study shows monoclinic unit cell having lattice parameters: a = 5.721(1) Å, b = 8.073(2) Å, c = 5.670(1) Å, β = 93.221(8)°, space group P_2/m and Z = 4. Average crystallite sizes determined by Scherrer equation are the range ~14-32 nm, whereas SEM micrographs show nano-micro meter size particles formed in ZnCo₂O₃. Endothermic peak at ~798 K in the Differential scanning calorimetric (DSC) trace without weight loss could be due to structural transformation and the endothermic peak ~1143 K with weight loss is due to reversible loss of O₂ in air atmosphere. Energy Dispersive X-ray (EDX) analysis profile shows the presence of elements Zn, Co and O which indicates the purity of the sample. Magnetic measurements in the range of +12 kOe to -12 kOe at 10 K, 77 K, 120 K and at 300 K by PPMS-II Physical Property Measurement System (PPMS) shows hysteresis loops having very low values of the coercivity and retentivity which indicates the weakly ferromagnetic nature of the oxide. Observed X-band EPR isotropic lineshapes at 300 K and 77 K show positive g-shift at g_iso ~2.230 and g_iso ~2.217, respectively which is in agreement with the presence of paramagnetic site Co²⁺(3d⁷) in the oxide. DC conductivity value of 2.875 ×10^-8 S/cm indicates very weakly semiconducting nature of ZnCo₂O₃ at 300 K. DRS absorption bands ~357 nm, ~572 nm, ~619 nm and ~654 nm are due to the d-d transitions ⁴T_1g(⁴F)→²E_g(²G), ⁴T_1g(⁴F)→⁴T_1g(⁴P), ⁴T_1g(⁴F)→⁴A_2g(⁴F), ⁴T_1g(⁴F)→⁴T_2g(⁴F), respectively in octahedral ligand field around Co²⁺ ions. Direct band gap energy, E_g~ 1.5 eV in the oxide is obtained by extrapolating the linear part of the Tauc plot to the energy axis indicates fairly strong semiconducting nature of ZnCo₂O₃.

• Journal of Conservation Science
• /
• v.34 no.3
• /
• pp.179-193
• /
• 2018

This study is aimed to investigate the provenance of raw materials and firing temperature of jar coffins excavated from the Oryang-dong kiln site and Jeonchon tomb site, Naju, Korea. Most of jar coffin samples shows same range of magnetic susceptibility and have gray color, while 404 and 405 of Jeongchon site are reddish yellow. In some samples fired at high temperature, the water absorption at the mouth rim and body part of same jar coffin were 3.50% and 7.56% respectively. It means that heat transfer and equilibrium in the kiln was not properly continued and the heat energy transferred to the mouth rim and the body part was different. In the petrographic analysis, As a tempering materials, biotite, weathered quartz and feldspar were added in the jar coffins of Oryang-dong site, and biotite, polycrystalline quartz and feldspar in it of Jeongchon site. Tempering materials were found more in the body than in the mouth rim of same jar coffin of Oryang-dong site. It seemed that some samples were fired at over 1,000 to $1,100^{\circ}C$, which showed vitrified texture in the scanning electron images and the rest of samples were fired at below $900^{\circ}C$. Due to similarity of chemical compositions, it is estimated that jar coffins of Jeongchon tomb were produced and supplied from Oryang-dong kiln site. However, the slight difference of some trace elements distribution of samples is attributed to the selection of clay depending on the location.