• Clean Technology
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• v.28 no.1
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• pp.38-45
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• 2022

CuCl₂-loaded V₂O₅-WO₃/TiO₂ catalyst showed excellent activity in the catalytic oxidation of elemental mercury to oxidized mercury even under SCR condition in the presence of NH₃, which is well known to significantly inhibit the oxidation activity of elemental mercury by HCl. Moreover, it was confirmed that, when SO₂ was present in the reaction gas together with HCl, excellent elemental mercury oxidation activity was maintained even though CuCl₂ supported on the catalyst surface was converted to CuSO₄. This is thought to be because not only HCl but also the SO₄ component generated on the catalyst surface promotes the oxidation of elemental mercury. However, in the presence of SO₂, the total mercury balance before and after the catalytic reaction was not matched, especially as the concentration of SO₂ increased. In order to understand the cause of this, further studies are needed to investigate the effect of SO₂ in the SnCl₂ aqueous solution employed for mercury species analysis and the effect of sulfate ions generated on elemental mercury oxidation. It was confirmed that SO₂ also promotes NO_x removal activity, which is thought to be because the increase in acid sites by SO₄ generated on the catalyst surface by SO₂ facilitates NH₃ adsorption. The composition change and structure of the components present on the catalyst surface under various reaction conditions were measured by XRD and XRF. These measurement results were presented as a rational explanation for the results that SO₂ enhances the oxidation activity of elemental mercury and the NO_x removal activity in this catalyst system.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.1009-1021
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• 2016

The community structure and abundance of epilithic biofilm were bimonthly examined to know spatial and temporal patterns of biofilm biomass and taxonimical composition at the two study sites, Gosapo and Gyeokpo with different degrees of wave exposure levels from November 2010 to September 2011. Biomass was estimated by using chlorophyll a contents (Chl a), normalized difference vegetation index (NDVI), and vegetation index (VI). Cyanobacteria such as Aphanotece spp. predominated in the proportion of 57.53% at Gosapo and of 61.12% at Gyeokpo and they are abundant in mid shore and in summer at both study sites. The diatoms Navicula spp., Achnanthes spp. and Licmophora spp. were common species and they showed an increasing trend from high to low shore. NDVI, VI, and chl a contents were the greatest at mid shore for Gosapo (0.44, 3.05, $24.56{\mu}g/cm^2$) and at low shore for Gyeokpo (0.41, 2.73, $17.98{\mu}g/cm^2$). NDVI, VI, and chl a content were all maximal in January and minimal in March at the both sites. Average NDVI, VI, and chlorophyll a contents of biofilms were greater at Gosapo (0.43, 2.89, $22.84{\mu}g/cm^2$) than Gyeokpo (0.38, 2.48, $15.48{\mu}g/cm^2$).Of three shore levels(high, mid, and low) Chl a contents were positively correlated with NDVI and VI at the two study sites indicating that non-destructive NDVI and VI values can be used in stead of destructive Chl a extraction method. In conclusion, epilithic biofilm was more abundant seasonally in winter, vertically in mid and low intertidal zone, and horizontally at wave exposed shore than in summer, at high and sheltered shore in Korea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.2
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• pp.97-105
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• 2011

This study investigated the community structure and spatio-temporal variation of macrobenthic assemblages around Gijang Province, East Sea of Korea. Macrobenthos collected seasonally using a modified van Veen grab sampler from March to November 2006. A total of 157 macrobenthic fauna were collected. The overall average macrobenthos density were $552 \;ind/m^2$. The species number of macrobenthos was in the range from 62 in winter and spring to 122 in autumn. On the other hand, abundance fluctuated between 6,540 (in spring) and 17,920 (in autumn) inds./$18m^2$. Cluster analysis and non-metric multi-dimensional scaling (nMDS) were applied to assess the spatio-temporal fluctuation in the macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 3 station groups. The group 1 (station 8~10, 12, 13, 17 and 18) was characterized by high abundance of the polychaete Lumbrineris longifolia, the bivalve Ennucula tenuis and the Amphipoda spp., with mean phi range from $6.2{\Phi}$ to $7.1{\Phi}$ (above 50m water depth). The group 2 (station 5~7, 11, 14~16) was numerically dominated by the po1ychaete Ampharete arctica and the bivalve Theorafragilis (mean phi: $6.0{\sim}7.0{\Phi}$; within 40 m water depth). Finally group 3 (station 1~4) was characterized by high density of the polychaetes Magelona japonica and Sternaspis scutata, with mean phi range from $3.5{\Phi}$ to $6.9{\Phi}$ (below 30 m water depth). In conclusion, the Macrobenthic community structure showed a distinct spatial and temporal trend, which seemed to be related to the water depth and sediment composition.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.328-341
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• 2004

Presowing seed treatments used to enhance the rates of germination and afterward seedling emergence have not occasionally shown the same rate in indoor and field. The treatments considering germination mechanism and factors affecting germination must be totally included in indoor experiments so that the results drawn can be reproduced in the field. Seed germination is controlled by Phytochrome-mediated action changed with composition rates of red and far-red lights. Sunlight can penetrate soil into $6{\sim}9\;mm$ depth, which in turn means that seeds having $2{\sim}3\;mm$ in their width may receive the light if soil was covered 3 times over them. The penetrating light, moreover, turns to more far-red light than red light reverse to the sunlight. For germination tests after the artificial presowing seed treatments, therefore, seeds of smaller than 2 mm (< 2 mm), $2{\sim}3\;mm$, and larger than 3 mm (> 3 mm) must be done with incandescent lamp (IL) having more far-red light, with IL or in darkness, and in darkness, respectively. The 96 papers published in 13 Korean scientific journals up to the end of 2003 were analysed on the basis of the above explanation. 91 species were used 147 times as experimental materials; 101 times for < 2 mm seeds, 24 times for $2{\sim}3\;mm$ seeds and 22 times for > 3 mm seeds. If they were analysed as the light sources used for germination tests, correct applications reached more and less than 60% in both $2{\sim}3\;mm$ and > 3 mm seeds but 23% in < 2 mm seeds, conclusionally meaning that when the experimental results in the scientific papers were applied into farming practices, care was taken of their application because most of medicinal plant seeds were very small.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.763-771
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• 2013

This study was carried out to investigate the effects of various temperatures of electro-magnetic resonance and air blast freezing methods on the physicochemical quality of meat. Beef (loin and round), pork (belly and ham) and chicken (breast and leg) were purchased at a commercial market, and the meat was frozen using three methods: air blast freezing ($-20^{\circ}C$ and $-45^{\circ}C$) and electro-magnetic resonance quick freezing. Changes in the physicochemical properties of meat were analyzed by drip loss, cooking loss, water holding capacity (WHC) and proximate compositions. In comparison, regardless of the animal species and cuts of meat, electro-magnetic resonance quick freezing (2 h) resulted in a completely frozen product in a much shorter time than $-20^{\circ}C$ and $-45^{\circ}C$ air blast freezing (24 h and 8 h, respectively). Drip loss of loin which had underwent electro-magnetic resonance quick freezing were significantly (p<0.05) lower than those of the other two treatments, but cooking loss and water holding capacity were the highest at 43.7% and 60.7%, respectively (p<0.05). Characteristics such as crude protein, crude fat and moisture compositions showed significant differences, depending on the cuts and freezing methods (p<0.05). The fat composition of electro-magnetic resonance quick frozen loin and round were significantly low (p<0.05). However, moisture content was the highest compared to other freezing methods, as 67.1% and 71.9%, respectively (p<0.05). Electro-magnetic resonance quick freezing was an appropriate way to reduce the deterioration of meat quality due to freezing, and the drip loss was least for the part with low moisture, low protein, and high fat.

• Journal of Environmental Science International
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• v.12 no.6
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• pp.665-676
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• 2003

To investigate the chemical characteristics of PM$\_$2.5/ in Seoul, Korea, atmospheric particulate matters were collected using a PM$\_$10/ dichotomous sampler including PM$\_$10/ and PM$\_$2.5/ inlet during the period of October 2000 to September 2001. The Inductively Coupled Plasma-Mass Spectromety (ICP-MS), ion Chromatography (IC) methods were used to determine the concentration of both metal and ionic species. A statistical analysis was performed for the heavy metals data set using a principal component analysis (PCA) to derived important factors inherent in the interactions among the variables. The mean concentrations of ambient PM$\_$2.5/ and PM/sub10/ were 24.47 and 45.27 $\mu\textrm{g}$/㎥, respectively. PM$\_$2.5/ masses also showed temporal variations both yearly and seasonally. The ratios of PM$\_$2.5/PM$\_$10/ was 0.54, which similar to the value of 0.60 in North America. Soil-related chemical components (such as Al, Ca, Fe, Si, and Mn) were abundant in PM$\_$10/, while anthropogenic components (such as As, Cd, Cr, V, Zn and Pb) were abundant in PM2s. Total water soluble ions constituted 30∼50 % of PM$\_$2.5/ mass, and sulfate, nitrate and ammonium were main components in water soluble ions. Reactive farms of NH$_4$$\^$+/were considered as NH$_4$NO$_3$ and (NH$_4$)$_2$SO$_4$ during the sampling periods. In the results of PCA for PM$\_$2.5/, we identified three principal components. Major contribution to PM$\_$2.5/ seemed to be soil, oil combustion, unidentified source. Further study, the detailed interpretation of these data will need efforts in order to identify emission sources.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.4
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• pp.519-534
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• 2019

When the fresh water from the artificial lakes (Ganwolho and Bunamho) were discharged to Cheonsu Bay in summer to prevent the flood over the reclaimed farmland near the lakes, the impact on water qualities (nutrients, organic matters, trace metals) within the bay was investigated through four surveys (June, July, August and October, 2011). Dissolved inorganic nitrogen (DIN) increased about as much as 3-4 times over the whole water column when the freshwater was discharged. And the main species composition of DIN changed from ammonia to nitrate. Dissolved inorganic phosphorus (DIP) decreased as much as 2 times in surface waters, but increased as much as 1.5 times in deep waters, and also silicate concentrations increased as much as 3-4 times in deep waters of the inner bay. The N/P ratios in Chunsu bay seawaters were much higher (2 to 7 times) than the Redfield ratio when the freshwaters were discharged, which indicated the phosphorus limiting in the phytoplankton growth. Dissolved organic carbon (DOC) and nitrogen (DON) increased as much as about 2 times. In addition, particulate organic matters (POC, PON, POP, Bio-Si) increased as much as above 2 times in the surface waters of the inner bay. Trace metals (Fe, Mn, Co, Ni, Cu) increased in the surface waters of the inner bay, but dissolved Cd concentrations decreased as much as 2 times. Therefore, when the contaminated fresh waters from the artificial lakes were discharged into the bay, nutrients, organic matters and trace metals generally increased compared to normal period. Since the phytoplankton bloom occurred in the surface waters of the inner bay, dissolved oxygens at the surface waters were oversaturated and hence hypoxic in the deep waters. Highly enriched nutrients concentrations were found in deep waters of the inner bay, which was accompanied with the hypoxic condition. Finally, the water quality in the inner bay of the Chunsu bay was deteriorated from less than grade 3 in normal periods to grade 5 when the freshwaters from the artificial lakes were discharged in summer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.93-101
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• 2014

Asymmetric 1,2-distearoyl-3-oleoyl-rac-glycerol (SSO) triacylglycerol (TAG) is used as a cocoa butter replacer (CBR). In this study, it was produced by lipase-catalyzed interesterification of fully hydrogenated soybean oil (FHSBO) and oleic ethyl ester (OEE) in a batch type reactor at $75^{\circ}C$, 250 rpm. Different molar ratios (FHSBO : OEE=1:1, 1:2 and 1:3, w/w) and various reaction times (1, 2, 3, 4, and 5 hr) were also tested. The optimized condition for SSO was a FHSBO : OEE molar ratio of =1:1 at reaction times of 2, 3, 4, and 5 hr. Enzymatic synthesis generated SSO/SOS, as well as the other TAGs (e.g., PSO/POS, SOO/OSO, SSS), ethyl esters, monoacylglycerol (MAG), and diacylglycerol (DAG). After scale-up, fractionation by solvent (methanol and acetone) fractionation and column chromatography was applied. To reduce ethyl esters, high-melting TAGs (e.g., SSS), and SOO/OSO in reactants, solvent fractionation was applied. Using a silica gel column (sample : silica gel=2:1, wt%), MAG and DAG were removed at $25^{\circ}C$. The major fatty acid composition of the final products (with a high SSO/SOS content) was palmitic acid (C16:0, 10.9~12.9 area%), stearic acid (C18:0, 52.2~54.9 area%), and oleic acid (C18:1, 34.2~35.5 area%). In reversed-phase HPLC analysis, the major TAG species of the final product (FHSBO : OEE=1:1, 2 hr) were SSO/SOS (82.31 area%) and PSO/POS (14.51 area%). Based on the $[SS]^+$ : $[SO]^+$ ratio obtained by RP-HPLC/APCI-MS, the final product had a higher SSO (AAB type TAG) content than cocoa butter (CB). The solid fat index (SFI) of CB and the final product obtained were similar with a narrow melting point range around ~32 to $35^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.842-853
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• 2014

For developing indigestible lipids, symmetric triacylglycerol (ST) and asymmetric triacylglycerol (AT) were produced by enzymatic interesterification using high oleic sunflower oil, palmitic ethyl ester, and stearic ethyl ester in a shaking water bath. Used enzymes were Lipozyme RMIM for ST and Lipozyme TLIM for AT. To remove ethyl ester from reactants, methanol fractionation (reactant : methanol=1:5, w/v, $25^{\circ}C$) and florisil separation (reactant : florisil=1:8, w/w) were applied. Acetone fractionation (reactant : acetone=1:9, w/v) was implemented to separate triacylglcerol (TAG) species into ST and AT. Fractions I (before fractionation), II (after fractionation, liquid phase) and III (after fractionation, solid phase) were separated from ST, whereas fractions IV (after 1st fractionation, liquid phase) and V (after 2nd fractionation, solid phase) were from AT. From sn-2 fatty acid composition analysis, the sum of palmitic acid (C16:0) and stearic acid (C18:0) was 4.9~6.5 area% in ST (I, II, III), and 41.9~43.9 area% in AT (IV, V). In vitro digestion was performed for 0, 15, 30, 60, and 120 minutes at $37^{\circ}C$ in a shaking water bath. For the digestion results, hydrolysis of V was only 40% compared to others (I, II, III, IV) at 120 minutes due to its melting point ($49^{\circ}C$). However, initially (15 minutes), hydrolysis (%) was as follows: V$32.5^{\circ}C$, $31.8^{\circ}C$) and different slip melting points ($31.3^{\circ}C$, $19.5^{\circ}C$). Even though IV has a lower TAG content composed of two saturated fatty acids than III, it had a similar melting point.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.223-245
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• 1983

Nationwide weed survey of paddy rice field conducted in 1981 and 1971 was compared and determined major dominant weed community types distributed by province. Based on the similarity coefficients between 1971 and 1981 the floristic composition based on the degree of dominance was greatly dissimilar while kind of weed flora were not much differed. Degree of dominance were concentrated to perennial weeds in 1981 while these were at animal weeds in 1971. The moat important 10 weed species and their dominance in 1981 were Monochoria vaginalis Presl.(22.2%), Sagittaria pygmaea Miquel(17.5%), S. trifolia L.(9.0%), Poramogeton distinctus Benn.(9.0%), Cyperus serotinus Rottb.(8.5%), Rotala indica Koehne(6.0%), Aneilema japonica Kunth(4.4%), Lindernia procumbens Philcox(3.9%), Eleocharis kuroguwai Ohwi(3.4%) and Ludwigia proarrara Roxb(3.0%), respectively while these for 1971 were R. indica(34.5%), Eleocharia acicularis Roem, et Schult (11.9%), M. vaginalis(11.1%), Cyperua difformis L.(8.7%), Echinochloa crus-galli Beauv.(6.9%), L. procumbens(3.3%), P. distinctus(3.1%), A. Japonica (2.4%), E. kuroguwai(1.8%) and P. hydropiper(1.8%), respectively. Weed occurrence was also closely related with soil type, cropping pattern and cultural practices. Particularly, the occurrence of P. distincrus was negatively correlated with the degree of land utilization. Weed community types dafined by two-dimensional ordination analysis were 11 for Jeonnam province, 9 for Gyeoaggi, Gangweon, Chungbuk and Gyeongnam provinces, 8 for Jeonbuk and Gyeongbuk provinces, 7 for Chungnam province and 4 for Jeju province, respectively.