• Economic and Environmental Geology
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• v.30 no.5
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• pp.477-491
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• 1997

In the Bibong area of the western part of Chungcheongnam-do, ultramafic masses occur as discontinuous isolated lenticular bodies in the Precambrian Kyeonggi gneiss complex. They extend for about 200 m long to NNE directions which are parallel to fault lines in the gneiss complex. The ultramafic masses contact with the adjacent gneiss complex as steeply dipping faults. They are dunites and harzburgites and many of them are partially or completely serpentinized. The ultramafic rocks dominantly show protogranular, equigranular and equigranular-$m{\grave{o}}saic$ textures. They also show porphyroclastic (megacrystic) or recrystallized textures reflecting several stages of metamorphism. They contain varying amounts of olivine $(Fo_{89-92})$, enstatitic to bronzitic orthopyroxene, diopsidic clinopyroxene, tremolitic to pargasitic hornblende, and spinel with serpentine, talc, chlorite, calcite and magnetite. The ultramafic rocks have high magnesium numbers and transitional element contents, low alkali contents and show deplete REE patterns. Comparing with available data, geochemical and mineralogical characteristics shown in the ultramafic rocks of the Bibong area are similar to those of worldwide mantle xenoliths and orogenic related ultramafic rocks. The field evidences, petrographical, geochemical and mineralogical characteristics shown in the ultramafic rocks of the Bibong area are similar to alpine type ultramafic rocks emplaced into the crust by the faulting as mantle slab types. With the petrographical characteristics, these mineralogical compositions suggest that the ultramafic rocks of the Bibong area have experienced several stages of retrogressive metamorphism in a condition ranging from the upper amphibolite facies to greenschist facies.

• Economic and Environmental Geology
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• v.30 no.5
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• pp.395-406
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• 1997

Some RE (Zr, Nb, REE) ore deposits are located in the middle part of the Korean peninsula. Geotectonically, the RE ore deposits situated on the Kyemyeongsan Formation of northern margin of the Okcheon geosynclinal belt and in the transitional zone between Kyeonggi massif and Okcheon belt. The rare metal deposits distributed in Kyemyeongsan Formation which consists of schist and alkaline granite. The alkali granite has suffered extensive post-magmatic metasomatism and hydrothermal processes. The ore contains mainly Ce-La, Ta-Nb, Y, Y-Nb, Ti-Nb-(U), Nd-Th group minerals. Fergusonite, one of Nb-Y rich REE minerals belonging to the A-B oxides, is most common mineral in the rare metal deposits. The fergusonite bearing rocks may be devided into four types by occurrence features and mineral association, that is, zircon type, allanite vein, feldspar type, and fluorite type. Fergusonites show wide variations in optical properties, due to part of differences in their chemical composition (depending on the types), but also the degree of crystalinity of the individual specimens. Fergusonite metamicts enclosed in biotite are generally surrounded by well developed pleochroic haloes. Usually, fergusonite is accompanied with zircon and other REE-bearing minerals. Petrographical and chemical data are presented for fergusonites which collected different types. $Nb_2O_3$ and $Y_2O_3$ contents range from 48.51 to 53.01 wt.% and 29.18 to 42.02 wt.% respectively. Also, $ThO_2$, (1.83~6.93), $UO_2$, (0.17~2.84), ${\sum}RE_2O_3$ (except to Y) (1.11~8.73), and $TiO_2$, (0.19~1.19 wt.%) contents show variational compositions according to fergusonite types. The ${\sum}RE_2O_3$ of fergusonites are positive relation with $Y_2O_3$ and negative relaton with $ThO_2$ and $({\sum}{RE_2O_3}-{Y_2O_3})$. The $Nb_2O_3$ is sightly negative relation with $Ta_2O_3$. Back-scattered electron microscope images (BEI) of fergusonite show the mineral composition and textural feature is very complicated. The variation of Nb, Th and REE content of fergusonite and the modes of occurrence of mineral, suggests that REE may have been mobilized during the circulation of hydrothermal fluids related to contact metamorphism (metasomatism). The chemical variation of the fergusonites with occurrences and mineral association can be related to metasomatism of alkaline fluid was probably the dominant ore-forming process in Chungju district.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.463-471
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• 1994

Physicochemical properties, gelatinization and retrogradation characteristics of surfactant added sweet potato starches were investigated. Three different surfactants, SSL (sodium stearoyl-2-lactylate), Dimodan (mono/diglyceride) and SE1670 (sucrose fatty acid ester 1670) were used. Shapes and crystallinities of starch granules were not changed by the addition of surfactants. Total lipid contents increased and the amylose content decreased by the addition of surfactants and the order was as follows: SE1670>SSL>Dimodan. The swelling power and solubility at $80^{\circ}C$ decreased in the surfactant added starches. By amylograph, initial gelatinization temperature of untreated sweet potato starch was $72.5^{\circ}C$, and did not change by the addition of surfactants, but SE1670 or Dimodan added starch showed the peak viscosity. The peak temperature of gelatinization and enthalpy of untreated starch by DSC were $53.9^{\circ}C$ and 1.3cal/g, respectively. The peak temperature increased by the addition of surfactants, while the enthalpy decreased. In gelatinization by alkali, the viscosity was lower in surfactant added starches than in untreated starch at concentration. The degree of retrogradation by ${\alpha}-amylase-iodine$ method was a lower in SSL and SE1670 added starches than untreated starch and the enthalpy by DSC also decreased in surfactant added and retrograded starches.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.136-142
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• 2010

Combustion reactivity and thermal behavior of two imported coals used as a pulverized fuel of commercially thermal power plant were investigated by thermogravimetric analysis (TGA) and large scale test furnace of 200 kg/hr. TGA results showed that combustion efficiency of high moisture coal has lower than reference coal due to the slow combustion completion rate although it has the low ignition temperature, and activation energies of high moisture coal with 79 kJ/mol for overall combustion was higher than reference coal of 53 kJ/mol. Test furnace results ascertained that flame of black band of high moisture coal during the combustion in boiler broke out compared to reference coal and then it becomes to unburned carbon due to the less reactivity and combustion rate. But, Blending combustion of high moisture coal with design coal of high sulfur are available because sulfur content of high moisture coal was too low to generate the low SOx content in flue gas from boiler during the combustion. The ash analysis results show that it was not expected to be associated with slagging and fouling in pulverized coal fired systems due to the low alkali metal content of $Na_2O$ and $K_2O$ compared to bituminous coal.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.115-129
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• 2015

The cut-slope of a large-sectional tunnel portal is recognized as a potential area of weakness due to unstable stress distribution and possible permanent displacement. This paper presents a case study of a slope failure and remediation for a large-scale cut-slope at a tunnel portal. Extensive rock-slope brittle failure occurred along discontinuities in the rock mass after 46 mm of rainfall, which caused instability of the upper part of the cut-slope. Based on a geological survey and face mapping, the reason for failure is believed to be the presence of thin clay fill in discontinuities in the weathered rock mass and consequent saturationinduced joint weakening. The granite-gneiss rock mass has a high content of alkali-feldspar, indicating a vulnerability to weathering. Immediately before the slope failure, a sharp increase in displacement rate was indicated by settlement-time histories, and this observation can contribute to the safety management criteria for slope stability. In this case study, emergency remediation was performed to prevent further hazard and to facilitate reconstruction, and counterweight fill and concrete filling of voids were successfully applied. For ultimate remediation, the grid anchor-blocks were used for slope stabilization, and additional rock bolts and grouting were applied inside the tunnel. Limit-equilibrium slope stability analysis and analyses of strereographic projections confirmed the instability of the original slope and the effectiveness of reinforcing methods. After the application of reinforcing measures, instrumental monitoring indicated that the slope and the tunnel remained stable. This case study is expected to serve as a valuable reference for similar engineering cases of large-sectional slope stability.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.218-221
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• 2008

The levels of sulfites in wooden chopsticks were analyzed using two different methods, distillation-alkali titration and ion chromatography. According to the two methods, Sulfur dioxide($SO_2$) was validated by 0.6 and 0.2 ${\mu}ml$ of limit of detection(LOD), 1.8 and 0.5 ${\mu}ml$ of limit of quantification, (LOQ) and a $R^2>0.998$ for linearity, respectively. The recoveries of $SO_2$ from food simulants spiked ar levels of 100 ppm were 70.2-100.2%. 158 samples of wooden chopsticks were monitored the migrated amounts of sulfites. Sulfites were detected in 30 samples in ranged of 0.6 to 15.5 ppm. Maximum migration level, 15.5 ppm of sulfites was considered giving no harmful effect to human since it was reached 5.5% of estimated SML.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.15-26
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• 2020

To recover phosphorus from incinerated sewage sludge ash(ISSA), ISSA were extracted with sulfuric acid solution, and the optimal phosphorus recovery conditions were experimented by comparing the recovered phosphorus contents and heavy metals by raising pH. Also the phosphorus recovery efficiency was compared when acid extract was reused or classified by particle size of ISSA. The optimal conditions for recovering phosphorus from ISSA were 1N sulfuric acid solution with an L/S ratio of 10, and an extraction time of 30 minutes. Considering the addition of alkali substances and the content of heavy metals in the recovered sediment, it is concluded to recover phosphorus under pH 5. Reuse of the ISSA extract increased the recovery rate of phosphorus by 14~21% depending on the reuse rate (100 and 50%), but it also increased zinc contents to 33 and 21%, and copper contents to 35 and 20%, respectively. The experiment of ISSA divided into four sections by particle size showed that there was no distinct advantage of phosphorous recovery by classification of certain particle size of ISSA. The removal of heavy metals from extracts through EDTA and cation exchange resin showed no definite effect.

• Analytical Science and Technology
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• v.14 no.5
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• pp.422-431
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• 2001

One pulp manufacture facility was selected as surveying facility to examine the discharged amount and generation mechanism of dioxins excepts for bleaching stage wastewater. In recovery and finishing process, 2,3,7,8-TCDF, OCDD and OCDF were mainly detected, and the ratio of PCDDs and 1,2,3,4,7,8-HxCDD as the concentration of 2,3,7,8-substitute isomer were discharged which is known as the typical emission pattern of pulp and paper manufacture facility, and the 1,2,3,7,8-PeCDD and 1,2,3,4,7,8-HxCDD were discharged more than 90% in toxic equivalent concentration. Also, the OCDD and 2,3,7,8-TCDF for 2,3,7,8-isomer concentration, and 1,2,3,7,8-PeCDD and 2,3,7,8-TCDF as toxic equivalent concentration were discharged in effluent. The detected PCDDs/PCDFs concentration were surveyed 0.2266 ng-TEQ/L for influent and 0.0377 ng-TEQ/L for effluent.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.35-49
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• 1990

A highly purified $(Na^+,\;K^+)-ATPase$ from the rectal gland of Squalus acanthias and from the electric organ of Electrophorus electricus has been used to raise antibodies in rabbits. The 97,000 dalton catalytic subunit and glycoprotein derived from the rectal gland of spiny shark were also used as antigens. The two $(Na^+,\;K^+)-ATPase$ holoenzymes and the two shark subunits were antigenic. In Ouchterlony double diffusion experiments, these antibodies formed precipitation bands with their antigens. Antibodies prepared against the two subunits of shark holoenzyme also formed precipitation bands with their antigens and shark holoenzyme, but not with eel holoenzyme. These observations are in good agreement with inhibitory effect of these antibodies on the catalytic activity of $(Na^+,\;K^+)-ATPase$ both from the shark and the eel, since there is very little cross-reaction between the shark anticatalytic subunit antibodies and the eel holoenzyme. The maximum antibodies titer of the anticatalytic subunit antibodies is found to be 6 weeks after the initial single exposure to this antigen. Multiple injections of the antigen increased the antibody titer. However, the time required to produce the maximum antibody titer was approximately the same. These antibodies also inhibit catalytic activity of $(Na^+,\;K^+)-ATPase$ vesicles reconstituted by a slow dialysis of cholate after solubilization of the enzyme in a presonicated mixture of cholate and phospholipid. In these reconstituted $(Na^+,\;K^+)-ATPase$ vesicles, effects of these antibodies on the fluxes of $Na^+$, $Rb^+$, and $K^+$ were investigated. Control or preimmune serum had no effect on the influx of $^{22}Na^+$ or the efflux of $^{86}Rb^+$. Immunized sera against the shark $(Na^+,\;K^+)-ATPase$ holoenzyme, its glycoprotein or catalytic subunit did inhibit the influx of $^{22}Na^+$ and the efflux of $^{86}Rb^+$. It was also demonstrated that these antibodies inhibit the coupled counter-transport of $Na^+$ and $K^+$ as studied by means of dual labeling experiments. However, this inhibitory effect of the antibodies on transport of ions in the $(Na^+,\;K^+)-ATPase$ vesicles is manifested only on the portion of energy and temperature dependent alkali metal fluxes, not on the portion of ATP and ouabain insensitive ion movement. Simultaneous determination of effects of the antibodies on ion fluxes and vesicular catalytic activity indicates that an inhibition of active ion transport in reconstituted $(Na^+,\;K^+)-ATPase$ vesicles appears to be due to the inhibitory action of the antibodies on the enzymatic activity of $(Na^+,\;K^+)-ATPase$ molecules incorporated in the vesicles. These findings that the inhibitory effects of the antibodies specific to $(Na^+,\;K^+)-ATPase$ or to its subunits on ATP and temperature sensitive monovalent cation transport in parallel with the inhibitory effect of vesicular catalytic activity by these antibodies provide direct evidence that $(Na^+,\;K^+)-ATPase$ is the molecular machinery of active cation transport in this reconstituted $(Na^+,\;K^+)-ATPase$ vesicular system.

• Journal of Yeungnam Medical Science
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• v.3 no.1
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• pp.41-48
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• 1986

Band 3, the predominent 95,000 dalton anion transport protein, is the major intrinsic glycoprotein of the human erythrocyte membrane. This anion carrier exists as a dimer and binds the cytoskeletons such as spectrin, ankyrin and actin. And the liposomes are vesicular structures which form spontaneouly upon hydration of phospholipids. These artificial lipid vesicles have been investigated as model of the biological membranes and as a mean of improving the delivery of nucleic acids, drugs, proteins and biological substances to specific target tissues and cells. In this study, we were purified Band 3 from the human erythrocyte membrane(ghost) was prepared by hemolysis of intact human erythrocyte with weak alkali-hypotonic solution. Band 6 was removed from ghost by extracting with solution of an ionic strength of 0.15. Band 3 and Band 4 were solubilized selectively by extracting Band 6-depleted ghosts with Triton X-100 under nondenaturing conditions. Band 3 was then purified from Triton X-100 extract treated with p-chloromercuribenzoate by sucrose density gradient ultracentrifugation. This purified Band 3 was incorporated into liposomes prepared by reverse-phase evaporation. Phosphatidyl L-serine and cholesterol(1 : 1 molar ratio) were dissolved in chloroform and then chloroform was removed by rotatory evaporation under reduced pressure. Band 3 solution without Triton X-100 was introduced into a mixture of lipids and diethylether. Diethylether was subsequently removed by evaporation. This purified Band 3 and its incorporation into liposomes were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.