• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.38-39
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• 2002

일반적인 세라믹스 분말 합성방법으로서 고상법과 침전법 등은 성분 원소들간의 균일한 혼합이 어렵고, 대부분 최종 생성물의 합성 온도가 높아서 다성분계에 대하여 단일 상을 유지하면서 미세한 분말을 얻기가 힘들다. 그러나, 최근 들어 이러한 단점을 보완하기 위한 방법으로서 비정질 citrate법, 무기 금속염을 이용한 sol-gel법 등과 같이 비교적 공정이 단순하면서 입도 분포가 좁고 재현성이 우수한 구형의 초미립 또는 나노 분말의 제조에 적합한 방법들이 많이 연구되고 있다[1]. (중략)

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.114-115
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• 2002

다성분계 세라믹스에 대하여 초미립 및 나노 분말을 제조하기 위해 공침법, 비정질 citrate법, 무기 금속염을 이용한 sol-gel법, 분무 열분해법 등과 같이 비교적 단순한 공정이면서 입도 분포가 좁고 재현성이 우수한 구형의 초미립 또는 나노 분말의 제조에 적합한 방법들이 많이 연구되고있다[1-3]. 분무 열분해법은 출발물질로 용액을 사용하고 미세한 액적(droplet)을 초음파 분무 후 열분해 하여 분말을 합성하는 방법으로, 입자의 조성이 균질하고 구형의 형상을 갖는 우수한 결정상을 얻을 수 있다. (중략)

• Korean Journal of Plant Resources
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• v.26 no.2
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• pp.303-309
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• 2013

This study was performed to clarify the effect of medium compositions and plant growth regulators on the shoot, root formation and growth of 'Jarang' grape for mass propagation of virus-free plant. The formation and growth of shoot were considerably favorable in half-concentration of MS medium. However, the formation of adventitious root per explants (avg. 2.1) was effective in higher concentration (two times) of MS medium. For sucrose concentration, 1% for the shoot formation, 3% for the adventitious root formation and 1% for the growth were observed as yield significant results. With the addition of 0.05% of activated carbon, the shoot growth was improved, and it was effective for the adventitious root formation and growth as well. A pH of 6.8 in the medium was the most suitable for mass propagation; the results showed significant enhancement in the number of nodes and the length of the shoot, 3.9 and 1.3 cm, respectively. The shoot growth was the most vigorous in BA 1.0 mg/L due to the impact of the growth regulator on the mass propagation in it. Consequently, 16.9 shoots per explant were formed in NAA 1.0 mg/L so good results were obtained.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.875-880
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• 2000

The production of glucoamylase and exopolygalacturonase from Cryptococcus laurentii Y-23 were investigated with the inducible substrates and mineral salts. Soluble starch induced only glucoamylase wherease pectin induced exopolygalacturonase as well as glucoamylase, and glucose did not induce glucoamylase whereas pectic acid induced a little amount of exopolygalacturonase. At the productions of two enzymes by inducible substrates for the 5 day-cultivation, the yeasts started log phase around 12 hours and mostly reached stationary phase around 36 hours. The best productivity of glucoamylase was observed with addition of soluble starch in the cultivation for 72 to 86 hours, and the high productivity of exopolygalacturonase was done by addition of both pectin and soluble starch in the cultivation for more than 72 hours. Without ammonium sulfate in the medium, however, cultural pH was so increased gradually that production of both enzymes were decreased and delayed as well. $Mn^{2+}$ increased both productivities of glucoamylase and exopolygalacturonase with 21% and 18%, respectively.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.519-533
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• 2010

Activity oefficients and solubilities of L-Alanine in aqueous solutions containing each of four electrolytes(NaCl, KCl, $NaNO_3$ and $KNO_3$) were measured at 298.15 K. The measurements of activity coefficients were carried out in the electrochemical cell coupled with two ion-selective electrodes(cation and anion), and the solubilities were measured by the gravimetric analysis of saturated solutions in equilibrium with the solid phase of L-alanine. To model the activity coefficients and solubilities of amino acid in the amino acid/electrolyte aqueous solutions, thermodynamic relations of the residual Helmholtz free energy in the amino acid/electrolyte aqueous solutions were developed based on the perturbed-chain statistical associating fluid theory(PC-SAFT) combined with the primitive mean spherical approximation(primitive-MSA). In the present model, it is assumed that the zwitterions of L-alanine are associated with each other and cross-associated with water molecules, and also cross-associated with the cation and anion dissociated from an electrolyte(inorganic salt). The activity coefficients and solubilities of L-Alanine calculated from the theoretical model proposed in this work are found to be well agreeable with experimental data.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.106-118
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• 2001

The chemistry of porewater and exchangeable nutrients of sediment was determined to define potential influence of sediment nutrients on the water quality and the phytoplankton growth in Taechong Reservoir in March and May of 2000. The sediment-water interface showed almost anoxic state, < 0.5 mg $O_2/l$. Conductivity of the porewater was higher 1.9${\sim}$2.6 fold than that of sediment, and its variation was greater in the shallow water. Eh ranged from -12mV to -148 mV and bulk density from $1.17\;g/cm^3$ to $1.30\;g/cm^3$ and they did not differ among stations. The water content in the sediment ranged from 58% to 72% and organics from 8% to 13%, and they were higher toward the lower part of reservoir. Soil texture was in the order of sand>clay>silt and sandy sediment accounted for 97% of the total sediment. The total bacterial numbers and diatom abundance were high in the downstream of the reservoir. In porewater and exchangeable nutrients of sediment, nitrogen and phosphorus were mostly consist of the particulate form. Inorganic nitrogen was mostly composed of $NH_4$. Nitrogen of porewater was mostly an inorganic form while exchangeable nutrients were composed an organic form. However, phosphorus was composed of dissolved organic fraction in the porewater while inorganic fraction in the exchangeable nutrients. Silicon content of sediment was much exchangeable nutrients with 63%, and it was higher than in the porewater. In summary, the sediments of Taechong Reservoir were mostly composed of organics and assessed to be a eutrophic state.

• Journal of Life Science
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• v.25 no.6
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• pp.673-679
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• 2015

The culture conditions needed to maximize the production of laccase from Pholiota highlandensis mycelia were investigated. Among the tested media for laccase production, Coriolus versicolor medium (CVM; 2% dextrose, 0.4% peptone, 0.6% yeast extract, 0.046% KH₂PO₄, 0.1% K₂HPO₄, 0.05% MgSO₄·7H₂O) showed the highest activity for the enzyme. Then, to optimize culture conditions for laccase activity, the influences of various carbon, nitrogen, phosphorus, and inorganic salt sources in CVM were investigated. The optimum culture medium was 2% fructose, 0.4% peptone with 0.6% yeast extract, 0.05% NaH₂PO₄, and 0.05% MgSO₄·7H₂O as carbon, nitrogen, phosphorus, and inorganic salt sources, respectively. Several aromatic compounds in the medium enhanced laccase activity to varying degrees. Guaiacol induced maximum laccase production, yielding 114.1 U/ml laccase activity after cultivation for 11 days at 25℃. The optimum pH and temperature for laccase production were 8.0 and 35℃, respectively. Native polyacrylamide-gel electrophoresis (PAGE) followed by laccase-activity staining with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the substrate was performed to identify the presence of laccase under the optimum conditions studied. Zymogram analysis of the supernatant culture showed an enzymatic band with a molecular mass of about 90 kDa.

• Korean Journal of Ecology and Environment
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• v.35 no.1 s.97
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• pp.1-9
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• 2002

In order to understand the relationship between succession of phytoplankton community structure and inorganic nutrients and particulate organic matters, a one station in Kyungan stream in Korea during the dry season was chosen. Water samplings were carried out once a week from 18 August to 13 November 1993. The DIN concentration distributed always abundantly, however, phosphate and silicate gradually reduced during the period. Phytoplankton community had a peak chlorophyll a concentration of $90.6\;{\mu}g/l$ in late summer (21 August 1993) and a second peak of $29.7\;{\mu}g/l$ in autumn (2 October 1993). After then late autumn was characterined by relatively low chlorophyll a concentration of $15{\sim}16\;{\mu}g/l$. Seasonal fluctuation of chlorophyll a concentrations were correlated with measured POC and PON concentrations: phytoplankton blooming may be a major factor controlling POC and PON concentrations in this ecosystem. Phosphate plays an most important role as a limiting factor of phytoplankton growth. However, when Si/P ratio low, silicate may be a more critical limiting factor than phosphate. Shifts of P-limitation to Si- limitation the succession of dominant phytoplankton can in duce: diatom to cyanobacteria such as Anabaena, Microcystis and Oscillatoria.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.8-20
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• 2006

This research was conducted to determine the plant growth and nutrient contents of potted chrysanthemum 'Lima Honey' as influenced by application rate of dolomite in three root media, peatmoss+vermiculite (1:1, v/v), peatmoss+composted rice hall (1:1, v/v), and peatmoss+composted pine bark (1:1, v/v). All root media contained polyacrylic acid sodium salt (PASS) at a rate of $4.5g L^{-1}$. In crop growth at 40 and 80 days after transplanting, elevated application rates of dolomite up to $6.0g L^{-1}$ in three root media increased fresh and dry weights per plant. But the treatment of $9.0g L^{-1}$ had less fresh and dry weights than those of $6.0g L^{-1}$. Tissue phosphorus content decreased and those of Ca and Mg increased by the elevated application rates of dolomite. Elevated application rates of dolomite in three root media resulted in the increase of pH, EC, and the concentrations of K, Ca, and Mg at 43 days after transplanting. Those at 80 days after transplanting were also increased, but the differences among treatments were less significant as compared to those at 43 days after transplanting. From the results of dry weight in potted chrysanthemum 'Lima Honey', the proper application rate of dolomite to three root media containing PASS at a rate of $4.5g L^{-1}$ were $6.0g L^{-1}$.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.21-34
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• 2006

This research was conducted to determine the plant growth and nutrient contents of potted chrysanthemum 'Lima Honey' as influenced by application rate of fused superphosphate (FSSP) in three root media, peatmoss+vermiculite (1:1, v/v; PV), peatmoss+composted rice hall (1:1, v/v; PR), and peatmoss+composted pine bark (1:1, v/v; PB). All root media contained polyacrylic acid sodium salt at a rate of $4.5g L^{-1}$. The treatment of $1.4g L^{-1}$ in PV and those of $0.7g L^{-1}$ in PR and PB had the greatest fresh and dry weights in each root medium at both 43 and 80 days after transplanting. Elevated application rates of FSPP increased tissue contents of N, P, and K at both 43 and 80 days after transplanting in PV medium. However, the differences in tissue contents of N, P and K in PR medium were less significant among treatments of FSPP. The pre-planting FSPP also less affected the tissue contents of nutrients at 80 days after transplanting as compared to those at 43 days after transplanting. Elevated application rates of FSPP in PV medium increased EC and the concentrations of $NO_3,\;P_2O_5$, K, Ca, and Mg in soil solution of root media at 43 days after transplanting. The EC in PV medium at 80 days after transplanting was higher than that at 43 days after transplanting. The EC in all root media at 80 days after transplanting was not different among treatments of FSPP.