• Analytical Science and Technology
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• v.18 no.1
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• pp.35-42
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• 2005

This study reports the effect of $Mg^{2+}$ ions on the behavior of the anionic surfactant in electrophoresis. Intractions of $Mg^{2+}$ ions with carboxylates and sulfonates resulted large changes in their apparent mobilities. A comprehensive analysis of the electroosmotic and electrophoretic mobilities reveals that major cause for the variation of the apparent mobilities of anions arises from the electroosmotic mobilities.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.2
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• pp.123-130
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• 2015

For the analysis of ⁹⁰Sr, which is a pure beta emitter, radiochemical separation from the main interfering elements such as Ca, Ba and Ra is required due to their similarity in chemical behavior to strontium. This study describes a radioanalytical procedure using extraction chromatography for separating Sr from interfering elements. The maximum capacity of the resin for Sr was approximately 6 mg per 1.5 mL of bed volume (BV). The recovery of Sr on the resin 1.5 mL (BV) was quantitative for the calcium level of 200 mg at the flow rate of 1 mL min^-1. However the chemical yield declined by increasing the flow rate by up to 5 mL min^-1 even at the calcium level of 200 mg. When using the same BV of Sr resin, the performance of the resin was enhanced as the cross-sectional area of the Sr resin column is small.

• Corrosion Science and Technology
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• v.22 no.5
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• pp.387-392
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• 2023

The objective of this study was to evaluate corrosion resistance of Zn-Al-Mg alloy coated steel in residential water with trace quantities of Cl^-. Comparative evaluations were performed using two commercial coated steel products, GI and Galvalume, as reference samples. Examination of corrosion morphology and measurement of weight loss revealed that the Zn-Al-Mg alloy coated steel exhibited higher corrosion resistance than reference samples. This finding suggests that the alloy coated steel possesses long-term corrosion resistance not only in highly Cl^- concentrated environments such as seawater, but also in environments with extremely low levels of Cl^- found in residential water. The primary factor contributing to the superior corrosion resistance of the Zn-Al-Mg alloy coated steel in residential water is the formation of an inhibiting corrosion product composed primarily of two phases: Zn₅(OH)₆(CO₃)₂ and Zn₅(OH)₈Cl₂·H₂O. The preferential dissolution of Mg from the corroded coating layer can increase alkalinity, which might enhance the thermodynamical stability of Zn₅(OH)₆(CO₃)₂.

• 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.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.503-511
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• 2023

The aim of this study was to investigate in vitro antioxidant activities of defatted Camellia japonica L. seeds (DCJS). The DCJS were extracted using ethanol and then fractionated with butanol (BuOH), ethyl acetate (EtOAc), chloroform, and hexane. To evaluate antioxidant activity of extract and fractions from DCJS, we investigated free radical scavenging activities such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺), hydroxyl radical (^•OH), and superoxide anion (O₂^-) radicals. The five extract and fractions of DCJS dose-dependently increased DPPH, ABTS⁺ and O₂^- radical scavenging activities. The BuOH fraction of DCJS showed the highest free radical scavenging activities among other extract and fractions. The contents of total polyphenol and flavonoid in BuOH fraction of DCJS were 23.26 mg GAE/g and 32.39 mg QE/g, respectively. The polyphenol and flavonoids contents of BuOH fraction has highest than other extract and fractions. In addition, BuOH and EtOAc fraction of DCJS contained 102.37 and 165.05 ㎍/g of camelliaside B, respectively. Therefore, DCJS has higher antioxidant activity and may be useful as a natural antioxidant material.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.309-316
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• 2019

Cropland is a major source of atmospheric nitrous oxide (N₂O) and we need technologies in the field of agriculture that can reduce the presence of N₂O. In this study, a field experiment encompassing six treatments was conducted to determine the efflux of N₂O in cropland during the growing season. An experimental plot was composed of two main sectors, no-tillage (NT) and conventional tillage (CT), which were subdivided into three plots according to types of nitrogen (N) sources: CF, chemical fertilizer; HV, hairy vetch+chemical fertilizer; and RY, rye+chemical fertilizer. The cumulative N₂O emissions were 179.8 mg N₂O m^-2 for CF-CT, 108.1 mg N₂O m^-2 for HV-CT, 303.5 mg N₂O m^-2 for RY-CT, 86.7 mg N₂O m^-2 for CF-NT, 73.8 mg N₂O m^-2 for HV-NT, and 122.7 mg N₂O m^-2 for RY-NT during the fallow season. The CT, HV, and RY of no-tilled soils were reduced by 51.8, 31.7 and 59.6%, respectively (p<0.001). Our results indicate that the use of no-tillage and hairy vetch practice rather than conventional tillage and chemical fertilizer practice can decrease N₂O emission.

• Advances in environmental research
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• v.11 no.1
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• pp.1-16
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• 2022

Amongst 27 isolates from deteriorated leather samples, Arthrobacter creatinolyticus KP015744 zzx28 was found to be an efficient collagenase producer. Collagenase production of 13.33 µmoles/min was shown at an optimum temperature at 37℃ after 72h and at pH 7.5 by using 2 ml/dL inoculum in 10 mg/ml collagen peptide type I as a substrate. In presence of Hg²⁺, EDTA and 𝛽-mercaptoethanol the collagenase production by the isolate was strongly inhibited however Fe²⁺, Ca²⁺and DMSO enhanced production of the enzyme. Specific activity was found to be 19.46×10³ U/mg and molecular weight 66 kD by SDS PAGE. Isolate also has potential to hydrolyze keratin which is another important protein found in leather. Experimental results propose that collagenase can be effectively used as a tool for collagen and keratin rich solid waste treatment.

• Analytical Science and Technology
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• v.33 no.1
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• pp.33-41
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• 2020

Wet precipitation samples were collected in Jeju City and Mt. Halla-1100 site (a site at an altitude of 1100 m on Mt. Halla) during 2011-2013, and their major ionic species were analyzed to examine the chemical composition and characteristics. A comparison of ion balance, electric conductivity, and acid fraction of precipitation revealed correlation coefficients in the range of r = 0.950~0.991, thereby implying the high quality of analytical data. Volume-weighted mean pH and electric conductivity corresponded to 4.86 and 25.5 µS/cm for Jeju City, and 4.98 and 15.1 µS/cm for Mt. Halla-1100 site, respectively. Ionic strengths of the wet precipitation in Jeju City and Mt. Halla-1100 site corresponded 0.3 ± 0.5 and 0.2 ± 0.2 mM, respectively, thereby indicating that more than 30 % of total precipitation was within a pure precipitation criteria. The precipitation with a pH range of 4.5 - 5.0 corresponded to 40.8 % in Jeju City, while the precipitation with a pH range of 5.0 - 5.5 corresponded to 56.9 % in Mt. Halla-1100 site, thereby indicating slightly more weak acidity than that in Jeju city. The volume-weighted mean concentration (µeq/L) of ionic species was in the order of Na⁺ > Cl^- > nss-SO₄^2- > NO₃^- > Mg²⁺ > NH₄⁺ > H⁺ > nss-Ca²⁺ > PO₄^3- > K⁺ > CH₃COO^- > HCOO^- > NO₂^- > F^- > HCO₃^- > CH₃SO₃^- at Jeju City area, while it corresponded to Na⁺ > Cl^- > nss-SO₄^2- > NO₃^- > NH₄⁺ > H⁺ > Mg²⁺ > nss-Ca²⁺ > PO₄^3- > CH₃COO^- > K⁺ > HCOO^- > NO₂^- > F^- > HCO₃^- > CH₃SO₃^- at Mt. Halla-1100 site. The compositions of sea salts (Na⁺, Cl^-, Mg²⁺) and secondary pollutants (NH₄⁺, nss-SO₄^2-, NO₃^-) corresponded to 66.1 % and 21.8 %, respectively, in Jeju City and, 49.9 % and 31.5 %, respectively, in Mt. Halla-1100 site. The acidity contributions in Jeju City and Mt. Halla-1100 site by inorganic acids, i.e., sulfuric acid and nitric acid, corresponded to 93.9 % and 91.4 %, respectively, and the acidity contributions by organic acids corresponded to 6.1 % and 8.6 %, respectively. The neutralization factors in Jeju City and Mt. Halla1100 site by ammonia corresponded to 29.8 % and 30.1 %, respectively, whereas the neutralization factors by calcium carbonate corresponded to 20.5 % and 25.2 %, respectively. From the clustered back trajectory analysis, the concentrations of most ionic components were higher when the airflow pathways were moved from the continent to Jeju area.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.24-24
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• 2023

본 실험은 한반도 극지 고산식물인 진퍼리꽃나무[Chamaedaphne calyculata (L.) Moench] 종자의 형태적 특성을 조사하고 변온조건과 저온처리 및 GA3 처리가 발아에 미치는 영향을 구명하고자 수행하였다. 진퍼리꽃나무 종자는 국립수목원 전시원에서 채종 후 4℃에 저온건조 저장하였으며 전자현미경(DVM6, Leica Microsystems GmbH, Wetzlar, Germany)을 이용하여 종자와 배의 길이를 측정하였다. 2022년 3월에 growth chamber 내에서 32일간 15/6℃, 25/15℃ 변온조건하에 배양하였으며, 저온층적처리(0, 40일) 및 GA3 처리(0/500/1,000mg·L^-1) 처리에 따른 발아 특성을 구명하였다. 진퍼리꽃나무 종자의 최종발아율(FGP)은 25/15℃ GA3 1000mg·L^-1 처리에서 42.2%로 가장 높게 조사되었다. 평균발아일수(MGT)는 15/6℃ 저온층적 처리에서 22.3일로 가장 높았으며, 대부분 15/6℃ 변온조건에서 25/15℃ 변온조건보다 6∼8일 높았다. 최종발아일의 평균은 약 12일로 확인되었다. 저온 층적처리 결과, 최종발아율(FGP)은 온도조건 25/15℃, 15/6℃에서 각각 32.2%와 11.1%를 보여 무처리구에서 조사된 24.4%와 10.0%보다 각각 7.8%, 1.1% 높게 나타났다. 호르몬처리 결과, 동일한 발아조건에서 GA3 500mg·L^-1 처리보다 1000mg·L^-1 처리에서 더 높은 발아율을 보였다. GA3 1000mg·L^-1 처리에서의 최종발아율(FGP)DKSH은 25/15℃, 15/6℃ 각각 42.2%와 30.0%를 보여 무처리구 보다 각각 17.8%, 20% 높게 나타났다.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.79-93
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• 2020

To determine the size distributions of water-soluble inorganic ionic species (WSIS) in roadside aerosols, sampling experiments were carried out in the urban roadside area of Jeju City on August 2018 and January 2019 by using the eight-stage cascade impactor sampler. The mass of roadside aerosols were partitioned at 57% in fine fraction, 36-37% in coarse fraction, and 6-7% in giant fraction, regardless of summer and winter. The mass concentrations of WSIS except for Na+ and SO42- in roadside aerosols were higher in winter than in summer. The size distributions of Na⁺, Mg²⁺, Ca²⁺ and Cl^- were characterized by bimodal types with coarse particle mode peaking around 3.3-4.7 ㎛ and 5.8-9.0 ㎛. The size distributions of NO₃^- and K⁺ shifted from a single fine mode peaking around 0.7-1.1 ㎛ in winter to bimodal and/or trimodal types with peaks around coarse mode in summer. SO₄^2- and NH₄⁺ showed a single fine mode peaking around 0.7-1.1 ㎛. The MMAD of roadside aerosols was lower than that of Na⁺, Mg²⁺, Ca²⁺ and Cl-. Based on the marine enrichment factors and the ratio values of WSIS and the corresponding value for sea water, the composition of roadside aerosols in Jeju City may be practically affected by terrestrial sources rather than marine source.