• Korean Journal of Pharmacognosy
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• v.40 no.2
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• pp.109-117
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• 2009

We examined the purity of six heparin samples by using heparinase, chondroitinase, $^{1}H-NMR$, and polyacrylamide gel electrophoresis. To obtain high molecular weight contaminants from heparin samples, heparinase I - digested samples were subjected to the exhaustive microcon filtration. The filtration process removed heparin-derived di- and oligosaccharides effectively. By combining chondroitinase ABC treatment and strong anion exchange - high performance liquid chromatography, the result showed all six samples contained chondroitin sulfate as a contaminant ranging from 1.3 to 14.9%. Among them, sample S3 showed the highest content of 14.9%, which was further analyzed by chondroitinase AC treatment to confirm chondroitin sulfate B (dermatan sulfate). $^{1}H-NMR$ chemical shifts of N-acetyl groups clearly suggested the existence of chondroitin sulfate B (sample S3) and oversulfated chondroitin sulfate (samples S2 and S4) as contaminants. In addition, polyacrylamide gel electrophoresis was useful for qualitative detection on the sample's purity. These results suggest that the tools of heparinase I and chondroitinase ABC in combination with NMR spectroscopy would give very useful information for investigation of heparin contaminants such as oversulfated chondroitin sulfate and dermatan sulfate in heparin samples.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.62-66
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• 2003

Physicochemical properties and mineral compositions of seaweed salts prepared with various seaweeds and concentrated sea water were determined. Ash content of sea mustard was highest (22.7%) and that of laver the lowest (9.8%). Sea mustard contained high amount of Na, while sea tangle and seaweed fusiforme contained high amounts of K and Ca. When insoluble solids were removed after incineration of dried salt, surface color of the salt whitened more due to increase in salt purity with resulting decreases in pH and oxidation-reduction potential (ORP), pH and ORP of the ashed salt decreased, and K and Ca contents increased, while Mg content decreased. Yield of seaweed salt was the highest in sea mustard, ORP was lowest in sea tangle and seaweed fusiforme, and K and Ca contents increased significantly in sea tangle and seaweed fusiforme salts. As the concentration of sea water increased, yield and purity of the salts increased with decrease in pH and ORP and increase in Ca and Mg contents. Seaweed salt showed the characteristic crystalline structure as viewed by SEM.

• Journal of the Korean Chemical Society
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• v.11 no.4
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• pp.132-137
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• 1967

A spectrophotometric method for the determination of major impurities, such as iron and copper, in high purity of antimony with 8-hydroxyquinoline (oxine) has been studied. The iron-oxinate is stable at the pH range 5.0 to 5.7, and the copper-oxinate at the pH range 3.5 to 4.0. To mask antimony in sulfuric acid solution of sample, author has investigated the effect of tartaric acid on antimony, and found that 10ml of 0.5M tartaric acid solution could mask up to 600mg of antimony. The absorbance of iron-oxinate was measured at 580$m{\mu}$ and iron could be determined, but it is necessary for copper-oxinate to measure at 410 and 580m respectively after removing heavy metals other than copper by back extraction with 15% solution of sodium hydroxide, and copper could be determined by making a correction for the amounts of iron present. Up to 150 ${\mu}g$ of iron (0.005-0.03%), and 100 ${\mu}g$ of copper (0.005-0.016%), in 500mg of antimony could be determined.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.191-197
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• 2010

Fine nickel metal powder of uniform morphology, narrow size distribution, and high purity was prepared from high purity metal solution. Slurry reduction method for the synthesis of metal powder was applied with a special interest in their fine and spherical shape. The products were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Well dispersed ultrafine nickel powder with the particle size range of 100~200 nm was produced from Ni-hydrazine precursor using hydrazine as a reductant for 90 min reaction in 4.5 M NaOH solution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.3
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• pp.327-333
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• 1999

Controlled Ca impurity implanted inner crack-like pore in the high purity alumina bi-crystal had been created by micro-fabrication technique, which includes ion implantation, photo-lithography, Ar ion milling, and hot press. The morphological change and the growth od crystals formed by heat treatment in Ca doped high purity single crystal alumina, were observed using optical microscopy. The dot was developed and hexagon like crystal appeared on inner surface of crack-like pore after heat treatment. Bar type crystals, probably CaO . $6Al_2O_3$, were observed on the inner surface of 100ppm Ca implanted specimen after 1 hour heat treatment at $1,500^{\circ}C$, but this bar type crystal disappeared after 1 hour heat treatment at $1,600^{\circ}C$. This disappearance means that there should be little increase of Ca solubility limit to alumina and/or changes of diffusion coefficient of Ca in alumina around this temperature.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.5
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• pp.649-655
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• 2011

Methane direct cracking can be utilized to produce $CO_x$ and $NO_x$-free hydrogen for PEM fuel cells, oil refineries, ammonia and methanol production. We present the results of a systematic study of methane direct cracking using a mixed conducting oxide, Y-doped $BaZrO_3$ ($BaZr_{0.85}Y_{0.15}O_3$), membrane. In this paper, dense $BaZr_{0.85}Y_{0.15}O_3$ membrane with disk shape was successfully sintered at $1400^{\circ}C$ with a relative density of more 93% via addition of 1 wt% ZnO. The ($BaZr_{0.85}Y_{0.15}O_3$) membrane is covered with Pd as catalyst for methane decomposition with an DC magnetron sputtering method. Reaction temperature was $800^{\circ}C$ and high purity methane as reactant was employed to membrane side with 1.5 bar pressure. The $H_2$ produced by the reaction was transported through mixed conducting oxide membrane to the outer side. In addition, it was observed that the carbon, by-product, after methane direct cracking was deposited on the Pd/ZnO-$BaZr_{0.85}Y_{0.15}O_3$ membrane. The produced carbon has a shape of sphere and nanosheet, and a particle size of 80 to 100 nm.

• Journal of the Korean Chemical Society
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• v.39 no.4
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• pp.252-256
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• 1995

A study was carried out for the development of direct determination of antimony in high purity copper metal without preseparation. The large excess of copper seemed to be performed as the matrix modifier to enhance the absorbance of antimony in copper metal. Sensitivity enhancement of Sb was obtained at the condition of the ashing temperature of $600^{\circ}C(20s){\sim}700^{\circ}C(10s)$ rather than $1000^{\circ}C(20s){\sim}1100^{\circ}C(10s)$, and the atomization temperature of $2200^{\circ}C.$ The operating pressure of argon gas was readjusted to the optimum condition at 2.0 kg/$cm^2.$ The linearity of the Sb calibration graph could be obtained in the range of 20 ppb up to 200 ppb Sb in existence of 5,000 ppm Cu with the coefficient of variation of about 5%.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.129-135
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• 2013

Recently, waste water treatment system is developed in small and middle size to get more economic advantage. Freeze concentration system has high thermodynamic efficiency and low energy consumption, can re-use purified water and cold energy obtained from ice. This study was experimentally performed to investigate pollution containment in frozen layer by cooling wall temperature, air-bubble flow methods, initial ice-lining thickness of frozen layer in NaCl aqueous solution and the representative heavy metals, Pb and Cr aqueous solution. As the result, a decrease in the cooling wall temperature bring a higher growth rate of ice front and the more solute was involved in frozen layer. The method to inject directly air-bubble into ice-liquid interface through ring shape nozzle gave high purity of ice compared to indirect method. Ice lining in 5mm thickness resulted in frozen layer with higher purity than 1mm thickness.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.845-852
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• 2011

The Spark Plasma Sintering(SPS) method offers a means of fabricating a sintered-body having high density without grain growth through short sintering time and a one-step process. A titanium compact having high density and purity was fabricated by the SPS process. It can be used to fabricate a Ti sputtering target with controlled parameters such as sintering temperature, heating rate, and pressure to establish the optimized processing conditions. The compact/target(?) has a diameter of ${\Phi}150{\times}6.35mm$. The density, purity, phase transformation, and microstructure of the Ti compact were analyzed by Archimedes, ICP, XRD and FE-SEM. A Ti thin-film fabricated on a $Si/SiO_2$ substrate by a sputtering device (SRN-100) was analyzed by XRD, TEM, and SIMS. Density and grain size were up to 99% and below $40{\mu}m$, respectively. The specific resistivity of the optimized Ti target was $8.63{\times}10^{-6}{\Omega}{\cdot}cm$.

• Resources Recycling
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• v.30 no.6
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• pp.76-82
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• 2021

The separation of palladium from crude metal, which is obtained from electronic waste using pyrometallurgy was achieved through electrolysis. This was done to recover high-purity copper. The oxidation potentials of these metals are a fundamental part of the analysis of electrolytic separation of palladium and impurity metals. To achieve this, copper, iron, and nickel were dissolved in the electrolyte, and palladium and aluminum were found to be recoverable from anode slime. During the electrolysis for palladium separation, palladium was present in the anode slime and was obtained with a recovery of 97.46 % indicating almost no loss. 4N-grade copper was recovered from the electrodeposition layer at the cathode.