• Analytical Science and Technology
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• v.16 no.5
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• pp.339-348
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• 2003

Determination of some PAHs in used engine oils have been carried out by extraction of the components into acetonitrile followed by GC/FID and synchronous spectrofluorimetric technique. 7 PAHs, such as acenaphthene (Ace), anthracene (Anth), benzo(a)pyrene (BaP), chrysene (Chry), phenanthrene (Phen), fluoranthene (Ft), and perlyrene (Per) in used engine oil sample were able to determine separately by synchronous spectrofluorimetry. Calibration curves for those components were linear for the concentration range of 0.4~166 ppb PAHs with the corelation factor of 0.9985~0.9999. The peak areas produced by GC/FID split ratio program were used for the calibration curves of the other 8 PAHs. Detection sensitivity of the synchronous spectrofluorimetry seems to be 100 times more sensitive than GC/FID method. The total amount of PAHs in the used engine oil were 5.5 ng/g for LNG (bus), 10.5 ng/g for LPG(taxi), 92.2 ng/g for gasoline-passenger car, and 130 ng/g for diesel trailer, respectively.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.527-531
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• 2006

We have prepared organophilic inorganic particles and polyimide (PI) nanocomposite having excellent thermal stability and high dielectric constant that can be used for electronic application such as capacitor. We have chosen barium titanate (BT), a high dielectric constantmaterial and its surface was coated with nylon 6 to improve the affinity with PI. The FT-IR and TEM studies showed that the organophilic inorganic particle (BTN) has a polymer shell with thickness of 5 nm. We have suggested that it is possible to control the thickness of coating surface and also indicated the relationship between the ratio of inside and outside radius of BTN and the weight fraction of BT. The PI nanocomposite films based on poly(amic acid) and BTN were prepared by cyclodehydration reaction. The homogeneous dispersion of BTN in PI matrix was identified by using SEM. We have investigated the effect of BTN content on the coefficient of thermal stability, integral procedural decomposition temperature (IPDT), and dielectric constant of PI nanocomposite films.

• Journal of Life Science
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• v.23 no.12
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• pp.1486-1494
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• 2013

A high protease-producing strain was isolated and identified from the digestive tract of octopus vulgaris by detecting a hydrolysis circle of protease and its activity. The strain was identified by morphology observation, biochemical experiments, and 16S rRNA sequence analysis. The protease obtained from the strain was purified by a three-step process involving ammonium sulfate precipitation, carboxy methyl-cellulose (CM-52) cation-exchange chromatography, and DEAE-Sephadex A50 anion-exchange chromatography. The properties of protease were characterized as well. The strain Bacillus sp. QDV-3, which produced the highest activity of protease, was isolated. On the basis of the phenotypic and biochemical characterization and 16S rRNA gene-sequencing studies, the isolate was identified as follows: domain: Bacteria; phylum: Firmicutes; class: Bacilli; order: Bacillales; family: Bacillaceae; and genus: Bacillus. The isolate was shown to have a 99.2% similarity with Bacillus flexus. A high active protease designated as QDV-E, with a molecular weight of 61.6 kDa, was obtained. The enzyme was found to be active in the pH range of 9.0-9.5 and its optimum temperature was $40^{\circ}C$. The protease activity retained more than 96% at the temperature of $50^{\circ}C$ for 60 min. Phenylmethylsulfonyl fluoride (PMSF) inhibited the enzyme activity, thus confirming that this protease isolated from Bacillus sp. QDV-3 is an alkaline serine protease. Metal ions, $Mn^{2+}$ and $Mg^{2+}$, were determined to enhance the protease activity, whereas $Ba^{2+}$, $Zn^{2+}$, and $Cu^{2+}$ were found to inactivate the enzyme.

• 보존과학연구
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• s.32
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• pp.75-87
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• 2011

The materials analysis is important in conservation science for cultural assets since conservators can make appropriate decision of treatment and environment through understanding manufacturing, period and materials. Palsapumdo is the painting of Palsapum which was given by Yi Sun-shin from the emperor Shinjong in The Ming Dynasty. Palsapumdo painted with various pigments on the fabric has remained to adhere a sheet of lining paper. In this study, we carried out the fiber identification about the fabric and lining paper and the analysis of the pigments. This study identified a fabric and a lining paper and analised pigments for the painting. As a result of fabric analysis, it was confirmed as cotton because ribbon twists and shape of kidney bean in a cross section. After the analysis of lining paper, color changed to yellow by Graff "C" staining tests, and had short fiber and tracheid. Therefore, it is supposed to be a paper which is made of conifer pulp. In addition, the results of SEM-EDS, the pigments are indicated as Orpiment($As_2S_3$), Minium($Pb_3O_4$), Hematite($Fe_2O_3$), Emeraldgreen ($C_2H_3As_3Cu_2O_8$), Ultramarine [$2(Na_2O{\cdot}Al_2O_3{\cdot}2SiO_2){\cdot}Na_2S_2$], talc[$Mg_3Si_4O_{10}(OH)_2$], bariumsulfate($BaSO_4$) and brass.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.223-228
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• 2011

The present study was conducted to determine the optimum in vitro culture condition for callus induction and plant regeneration from mature seeds of bermudagrass (Cynodon dactylon cv. Common). It was revealed that mature seeds cultured on MS medium supplemented with 2 mg/L 2,4-D, 0.5 g/L proline, 0.5 g/L casamino acid and 3 g/L Gelrite under light condition produced the highest percentage of callus formation (39.2%). The most suitable medium for plant regeneration from dehydrated calli was MS agar medium supplemented with 0.5 mg/L 2,4-D, 2 mg/L BA, 0.5 g/L proline, 0.5 g/L casamino acid 3 g/L Gelrite which induced the highest percentage of calli forming shoots (57.7%). The frequency of callus induction and plant regeneration were the highest on sucrose, followed by maltose. The shoots were rooted at the highest rate (100%) when transferred onto 1/2 MS medium. Regenerated plants were morphologically uniform with normal growth pattern.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.217-222
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• 2011

Success in molecular breeding for better adapted varieties to environmental stresses depend upon the concerted efforts by various research including tissue culture, transformation, genetics and breeding. In order to optimize tissue culture conditions of Siberian wildrye grass, the effects of plant growth regulators on callus induction and plant regeneration were investigated with mature seeds. The highest callus induction frequency was observed when the mature seeds were cultured on MS medium supplemented with 5 mg/L 2,4-D. The highest plant regeneration frequency was observed when callus was transferred to N6 medium supplemented with 1 mg/L 2,4-D and 3 mg/L BA. Regenerated plants were grown normally when shoots were transplanted to the soil. A short tissue culture period and regeneration system would be beneficial for molecular breeding of Siberian wildrye grass by the production of transgenic plant.

• Geosciences Journal
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• v.23 no.1
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• pp.1-20
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• 2019

We present data from the Mesozoic Keumkang, Palbong, and Baekhwa granites in Garorim Bay, in the southwestern part of the Gyeonggi massif, South Korea. Using major and trace element concentrations, Sr-Nd-Pb isotopic compositions, and sensitive high-resolution ion microprobe (SHRIMP) zircon U-Pb ages, we aim to constrain the petrogenesis of the granites and explain their origin within a broader regional geological context. SHRIMP U-Pb zircon ages of $232.8{\pm}3.2$, $175.9{\pm}1.2$, and $176.8{\pm}9.8$ Ma were obtained from the Keumkang, Palbong and Baekhwa granites, respectively. The Late Triassic Keumkang granites belong to the shoshonite series and show an overall enrichment in large ion lithophile elements (LILE), a depletion in high field strength elements (HFSE) relative to primitive mantle, compared with neighboring elements in the primitive mantle-normalized incompatible trace element diagram with notable high Ba and Sr contents, and negligible Eu anomalies. The Keumkang granites are typified by highly radiogenic Sr and unradiogenic Nd and Pb isotopic compositions: $(^{87}Sr/^{86}Sr)_i=0.70931-0.70959$, $(^{143}Nd/^{144}Nd)_i=0.511472-0.511484$ [$({\varepsilon}_{Nd})_i=-17.0$ to -16.7], and $(^{206}Pb/^{204}Pb)=17.26-17.27$. The Middle Jurassic Palbong and Baekhwa granites belong to the medium- to high-K calc-alkaline series, and show LILE enrichment and HFSE depletion similar to the Keumkang granites, but exhibit significant negative anomalies in Ba, Sr, and Eu. Furthermore, they have elevated Y and Yb contents at any given $SiO_2$ content compared with other Jurassic granitoids from the Gyeonggi massif. The Palbong and Baekhwa granites have slightly less radiogenic Sr and more radiogenic Nd and Pb isotopic compositions [$(^{87}Sr/^{86}Sr)_i=0.70396-0.70908$, $(^{143}Nd/^{144}Nd)_i=0.511622-0.511660$, $({\varepsilon}_{Nd})_i=-15.4$ to -14.7, $(^{206}Pb/^{204}Pb)=17.56-17.76$] relative to the Keumkang granites. The Keumkang granites are considered to have formed in a post-collisional environment following the Permo-Triassic Songrim orogeny that records continent-continent collision between the North and South China blocks, and may have formed by fractional crystallization of metasomatized lithospheric mantle-derived mafic melts. The Palbong and Baekhwa granites may have been produced from a gabbroic assemblage at pressures of less than ~15 kbar, associated with subduction of the paleo-Pacific (Izanagi) plate at the Eurasian continental margin. Elevated ${\varepsilon}_{Nd}(t)$ values in the granitoids from the southwestern part of the Gyeonggi massif relative to those of the central and northern parts, together with the comparatively shallow depth of origin, imply the presence of an exotic block in the Korean lithosphere.

• Journal of Plant Biotechnology
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• v.49 no.1
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• pp.82-89
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• 2022

In vitro techniques were developed for propagating Vaccinium oldhamii using shoots with apical buds. Explants having an apical bud were cultured on Murashige and Skoog (MS) medium supplemented with 1.0, 2.0, and 5.0 mg/L of each zeatin, thidiazuron, 6-benzylaminopurine (BA), and 6-(γ,γ-dimethylallylamino)purine (2-iP) in order to induce multiple shoots. Among the tested treatments, the 2.0 mg/L of 2-iP proved to be most suited for the multiplication and growth of shoots; the multiple shoot induction rate was 100.0%, the average number of shoots was 7.4 per explant, and the average shoot length was 51.7 mm. The in vitro elongated shoots were rooted on half-strength MS medium containing various concentrations of indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA). However, overall callus overgrowth was observed in all treatments and resulted in necrosis and abnormal shoot growth in root formation. A low concentration (0.5 mg/L) of IBA was appropriate for normal root development and the in vitro rooting rate was 30%. Ex vitro treatments on root formation using various concentrations of IBA with Talc powder and two types of rooting substrates (Flexi-Plugs or Horticultural soil) were examined. The ex vitro rooting rate (80%) and length of roots (32.9 mm) were obtained when the cut ends of the shoots were treated with 1.0 mg/L IBA and cultivated in Horticultural soil for 2 months. These findings suggest that ex vitro rooting is the more effective method for improving root formation in Vaccinium oldhamii than in vitro rooting.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.83-100
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• 2022

The Zhenzigou Pb-Zn deposit, which is one of the largest Pb-Zn deposit in the northeast of China, is located at the Qingchengzi mineral field in Jiao Liao Ji belt. The geology of this deposit consists of Archean granulite, Paleoproterozoinc migmatitic granite, Paleo-Mesoproterozoic sodic granite, Paleoproterozoic Liaohe group, Mesozoic diorite and Mesozoic monzoritic granite. The Zhenzigou deposit which is a strata bound SEDEX or SEDEX type deposit occurs as layer ore and vein ore in Langzishan formation and Dashiqiao formation of the Paleoproterozoic Liaohe group. White mica from this deposit are occured only in layer ore and are classified four type (Type I : weak alteration (clastic dolomitic marble), Type II : strong alteration (dolomitic clastic rock), Type III : layer ore (dolomitic clastic rock), Type IV : layer ore (clastic dolomitic marble)). Type I white mica in weak alteration zone is associated with dolomite that is formed by dolomitization of hydrothermal metasomatism. Type II white mica in strong alteration zone is associated with dolomite, ankerite, quartz and alteration of K-feldspar by hydrothermal metasomatism. Type III white mica in layer ore is associated with dolomite, ankerite, calcite, quartz and alteration of K-feldspar by hydrothermal metasomatism. And type IV white mica in layer ore is associated with dolomite, quartz and alteration of K-feldspar by hydrothermal metasomatism. The structural formulars of white micas are determined to be (K_0.92-0.80Na_0.01-0.00Ca_0.02-0.01Ba_0.00Sr_0.01-0.00)_0.95-0.83(Al_1.72-1.57Mg_0.33-0.20Fe_0.01-0.00Mn_0.00Ti_0.02-0.00Cr_0.01-0.00V_0.00Sb_0.02-0.00Ni_0.00Co_0.02-0.00)_1.99-1.90(Si_3.40-3.29Al_0.71-0.60)_4.00O₁₀(OH_2.00-1.83F_0.17-0.00)_2.00, (K_1.03-0.84Na_0.03-0.00Ca_0.08-0.00Ba_0.00Sr_0.01-0.00)_1.08-0.85(Al_1.85-1.65Mg_0.20-0.06Fe_0.10-0.03Mn_0.00Ti_0.05-0.00Cr_0.03-0.00V_0.01-0.00Sb_0.02-0.00Ni_0.00Co_0.03-0.00)_1.99-1.93(Si_3.28-2.99Al_1.01-0.72)_4.00O₁₀(OH_1.96-1.90F_0.10-0.04)_2.00, (K_1.06-0.90Na_0.01-0.00Ca_0.01-0.00Ba_0.00Sr_0.02-0.01)_1.10-0.93(Al_1.93-1.64Mg_0.19-0.00Fe_0.12-0.01Mn_0.00Ti_0.01-0.00Cr_0.01-0.00V_0.00Sb_0.00Ni_0.00Co_0.05-0.01)_2.01-1.94(Si_3.32-2.96Al_1.04-0.68)_4.00O₁₀(OH_2.00-1.91F_0.09-0.00)_2.00 and (K_0.91-0.83Na_0.02-0.01Ca_0.02-0.00Ba_0.01-0.00Sr_0.00)_0.93-0.83(Al_1.84-1.67Mg_0.15-0.08Fe_0.07-0.02Mn_0.00Ti_0.04-0.00Cr_0.06-0.00V_0.02-0.00Sb_0.02-0.01Ni_0.00Co_0.00)_2.00-1.92(Si_3.27-3.16Al_0.84-0.73)_4.00O₁₀(OH_1.97-1.88F_0.12-0.03)_2.00, respectively. It indicated that white mica of from the Zhenzigou deposit has less K, Na and Ca, and more Si than theoretical dioctahedral mica. Compositional variations in white mica from the Zhenzigou deposit are caused by phengitic or Tschermark substitution [(Al³⁺)^VI+(Al³⁺)^IV <-> (Fe²⁺ or Mg²⁺)^VI+(Si⁴⁺)^IV] substitution. It means that the Fe in white mica exists as Fe²⁺ and Fe³⁺, but mainly as Fe²⁺. Therefore, white mica from layer ore of the Zhenzigou deposit was formed in the process of remelting and re-precipitation of pre-existed minerals by hydrothermal metasomatism origined metamorphism (greenschist facies) associated with Paleoproterozoic intrusion. And compositional variations in white mica from the Zhenzigou deposit are caused by phengitic or Tschermark substitution [(Al³⁺)^VI+(Al³⁺)^IV <-> (Fe²⁺ or Mg²⁺)^VI+(Si⁴⁺)^IV] substitution during hydrothermal metasomatism depending on wallrock type, alteration degree and ore/gangue mineral occurrence frequency.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.124-141
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• 1998

The objectives of this study are to investigate the trace (minor) elemental and isotopic compositions of calcitic skeletons, such as barnacle, echinoid, branching and encrusting calcareous algae and oyster, from the eastern coast of Korean peninsula and Cheju Island, and to compare their variations with latitude, that is, the temperature of ambient seawater at which the skeletons grew. Articulated and encrusting red algae are composed of high-Mg calcite (7-21 mol% $MgCO_3$). Echinoids are also composed of high-Mg calcite (7-15 mol% $MgCO_3$). Whereas barnacles are composed of low-Mg calcite (1-5 mol% $MgCO_3$). The Mg compositions of articulated red algae, barnacle and oyster tend to increase with increasing water temperature, whereas those of encrusting red algae and echinoid do not show any trend. Sr compositions of articulated red algae, echinoid and barnacle tend to decrease with increasing water temperature, whereas those of encrusting red algae and oyster do not show any trend. Mn compositions of articulated red algae and encrusting red algae decrease with an increase of water temperature, whereas those of echinoid and barnacle do not show any trend. Fe compositions of articulated red algae tend to decrease with increasing water temperature, whereas those of encrusting red algae and oyster increase. Fe compositions of echinoid and barnacle do not show any trend with water temperature variations. Ba compositions of echinoid and low-magnesium calcitic skeletons do not show any trend with water temperature variations. Ba compositions of articulated red algae tend to decrease with increasing water temperature, whereas those of encrusting red algae increase. Cd and Pb compositions of all the skeletons tend to increase with increasing water temperature. Cu compositions of encrusting red algae increase with increasing water temperature, whereas articulated red algae, echinoid, barnacle and oyster do not show any trend. Zn compositions of high-magnesium calcitic skeletons and low-magnesium calcitic skeletons do not show any trend. Estimated water temperatures from oxygen isotopic data of all the skeletons except for the barnacle arc higher than the range of temperature of the shallow seawater of the East Sea and around Cheju Island. The oxygen isotopic compositions of oyster and echinoid are well clustered, and they do not show any trend with increasing water temperature. Therefore, this could reflect that the organisms have not secreted their shells in oxygen isotopic equilibrium with ambient seawater due to vital effect. Thus, the oxygen isotopic composition of barnacle can potentially be utilized for paleotemperature estimate whereas those of other organisms in this study may not be useful.