• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.55-58
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• 1993

In order to determine the cobalt substituting site in $AlPO_4-5$ framework, ASED-MO theory has been used. The substitution of cobalt for aluminum is energetically more favorable than that for phasphorous. The stabilized energy of the former is 51 eV lower than that of the latter. The calculated net charge was +1.27 for Al, +0.85 for P, and +1.56 for Co, respectively. The valence electron population (VEP), reduced overlap population (ROP) and net charge for the charged cluster models were compared for $AlPO_4-5$ and $CoAlPO_4-5$ systems. Then, twe find that the covalency of P-O bond was greater than that of Al-O bond.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.602-607
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• 2009

논에서 수질변화특성에 관한 메카니즘은 매우 복잡하다. 영양물질의 농도특성을 정확히 파악하기 위해서는 영농활동에 따른 체계적인 모니터링을 통한 다양한 측정 자료가 필요하다. 그러나 현재 논에서 토양의 산화환원에 관한 연구 자료는 많지 않기 때문에 그의 특성을 파악하기에는 어려운 실정에 있다. 본 연구의 목적은 충북대학교 부속농장 필지논에서 2008년 영농기간을 중심으로 논에서의 영양물질인 총인(TP), 인산성 인($PO_4-P$) 및 산화환원전위(Eh)의 변화특성을 파악함으로써, 논으로부터의 영양물질 유출제어에 관한 기초 자료를 제공하는데 있다. 이 연구는 2008년 6월부터 10월까지 필지논에서 논 표면수의 TP 와 $PO_4-P$의 농도변화와 토양의 산화환원전위(Eh)와의 관계 특성을 파악하였다. 관개기의 논에서 인은 분얼비 시기에 인성분이 시비되지 않았는데도 불구하고 분얼비 직후와 분얼비 1주일 후에 TP농도가 높게 나타났는데 이는 담수의 영향으로 논이 환원상태로 되어, 논바닥에 침전된 철이온에 흡착되어 있던 인이 철이온의 환원으로 함께 용출하기 때문이라고 생각된다. 산화환원전위(Eh)는 높아지면 산화경향을, 낮아지면 환원경향을 나타낸다. 본 연구기간 동안의 산화환원전위(Eh) 값은 비 관개기에 $201^{\sim}405$ mV로 높게 나타났고, 관개기에는 $93^{\sim}195$ mV로 낮게 나타났다. 필지논 표면수의 인농도는 분얼비 직후 1주일후까지 TP 와 $PO_4-P$ 농도는 같이 상승하다가 TP농도는 약 2주일까지 더 상승하여 2008년 최대값을 나타냈고 $PO_4-P$농도는 하강하였는데 이는 논 토양이 환원상태로 되면서 바닥에 있던 입자성 인이 논 표면으로 떠올랐기 때문으로 사료된다. 그 후에 담수가 끝나는 시점까지 농도는 낮아졌다. 강우량이 적은 관개초기에 인의 농도는 비교적 높게 나타났지만 강우량이 많은 여름에는 작물의 생장에 필요한 영양물질 섭취 등으로 인농도가 낮게 나타나 논은 인의 유출을 억제하고 있는 것으로 나타났다. 이와 같이 인의 유출특성 및 산화환원전위(Eh)의 변화에 따른 논에서의 유출부하 특성이 규명된다면, 환경부하가 적은 효과적인 물관리가 가능해 질 것으로 판단된다.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.31-39
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• 2021

In this paper, warpage analysis that separates PCB for PoP (Package on Package) into unit and substrate using FEM (Finite Element Method), analysis of the effect of layer thickness on warpage, and SN (Signal-to-Noise) ratio by Taguchi method was carried. According to the analysis result, the contribution of the circuit layer on warpage was very high in the unit PCB, and the contribution of the outer layer was particularly high. On the other hand, the substrate PCB had a high influence of the circuit layer on warpage, but it was relatively low compared to the unit PCB, and the influence of the solder resist was rather increased. Therefore, considering the unit PCB and the substrate PCB at the same time, it is desirable to design the PCB for PoP layer-by-layer structure so that the outer and inner circuit layers are thick, the top solder resist is thin, and the thickness of the bottom solder resist is between 5 ㎛ and 25 ㎛.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.745-753
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• 2007

By struvite and hydroxyapatite crystallization, was high concentration of nitrogen and phosphorus in wastewater simultaneously. Particularly, removal of nitrogen and phosphate for crystallization have been applied to landfill leachates and animal wastewater. The purpose of this study is to decide the optimum struvite crystallization factors, sequence of $Mg^{2+}$ addition, pH control and the molar ratio of $Mg^{2+}$ over $PO_4^{3-}$. In conclusion, dosage of the magnesium followed by pH control formed magnesium hydroxide, so pH was decreased. Therefore, pH adjustment should followed by after magnesium dosage and then pH should be adjusted to 11. Over pH 10, it was not good for struvite crystallization efficiency by side reaction. Following of the $Mg^{2+}$ and the $PO_4^{3-}$ are dosed excessively, the removal efficiency of the $NH_4^+$ increased. A molar ratio of $Mg^{2+}:NH_4^+:PO_4^{3-}$, 1.3:1:1.3 was the most on effective for $NH_4^+$ removal at pH 9.5. But for the perfect removal $NH_4^+$, it is thought to be that molar ratio should be 2:1:2.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.4
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• pp.306-317
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• 2014

This study has been executed to understand the additional and removal processes of nutrients in the Saemangeum Salt-water Lake, and discussed with other monthly-collected environmental parameters such as water temperature, salinity, dissolved oxygen, suspended solids, and Chl-a from 2008 to 2010. $NO_3$-N, TP, $PO_4$-P, and DISi showed the removal processes along with the salinity gradients at the surface water of the lake, whereas $NO_2$-N, $NH_4$-N, and Chl-a showed addition trend. In the bottom water all water quality parameters except $NO_3$-N appeared addition processes indicating evidence of continuous nutrients suppliance into the bottom layer. The mixing modelling approach revealed that the biogeochemical processes in the lake consume $NO_3$-N and consequently added $NH_4$-N and $PO_4$-P to the bottom water during the summer seasons. The $NH_4$-N and $PO_4$-P appeared strong increase at the bottom water of the river-side of the lake and strong concentration gradient difference of dissolved oxygen also appeared in the same time. DISi exhibited continuous seasonal supply from spring to summer. Internal addition of $NH_4$-N and $PO_4$-P in the river-side of the lake were much higher than the dike-side, while the increase of DISi showed similar level both the dike and river sides. The temporal distribution of benthic flux for DISi indicates that addition of nutrients in the bottom water was strongly affected by other sources, for example, submarine ground-water discharge (SGD) through bottom sediment.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.808-822
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• 2014

넙치 (Paralichthys olivaceus)로부터 elastase-like serine protease (PoElSp)를 암호화하는 cDNA를 클로닝하여 그 서열을 분석한 결과, PoElSp 유전자는 269 아미노산을 암호화하는 978염기쌍으로 구성되었다. PoElSp 유전자의 조직 특이적 발현 양상을 RT-PCR법으로 조사한 결과, 간, 비장 및 소장에서 그 발현이 크게 나타났다. lipopolysaccharide (LPS)로 인위적 세균감염을 유도한 후, 1시간째에 콩팥에서, 3시간째에는 근육에서, PoElSp 유전자의 발현이 크게 증가하였다. 또한, 이 유전자의 발현은 비장에서 LPS 주입 후 1-24시간동안 점차로 증가하였다. pro-mature PoElSp (proPoElSp)에 해당하는 cDNA를 pET32a 벡터 시스템을 이용하여 대장균에서 발현시켰다. 이 재조합 proPoElSp 단백질의 활성은 gelatin zymography 방법과 합성형광 Z-Phe-Arg-AMC의 분해법을 이용하여 측정하였다. 단백질 분해효소 활성을 위한 최적 pH는 7.5였다. 실험결과들을 종합하면, PoElSp 단백질은 면역 반응에서 중추적 역할을 하리라 판단된다.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.269-276
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• 2003

The study was performed to understand the relationships of cyanobacterial bloom and environmental factors in Lake Daechung. The samples were collected weekly from June to October in 2001. The cyanobacterial bloom was divided into the three phases of the early phase, the middle phase and the late phase by phytoplankton standing crops. For the early phase, the correlation coefficients between chl- a and TP, and chl- a and $PO_4$-P were 0.986 and 0.894 respectively. Therefore, phosphorus was a main environmental factor in the development of cyanobacterial bloom. Zeu/Zm ratio and chl-a showed negative correlation of r = -0.995. At the late phase, $PO_4$-P showed the highest relationship (r = 0.958), and TP and temperature showed relatively high relationships (r = 0.857 and r = 0.813). At the late phase, $NH_3$-N showed highly positive relationship (r = 0.921). It was confirmed that $PO_4$-P was the most important contribution factor for the bloom through the regression analysis on the environmental factors. As the result, the decrease of Zeu/Zm ratio and the increase of P concentration influenced cyanobacterial bloom developed rapidly in the early phase. Also the cyanobacterial bloom was decreased in proportion to decreasing of $NH_3$-N concentration in the late phase. It was expected that observation of $NH_3$-N may be a very useful factor on monitoring of the decreasing situation of the bloom.

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.96-106
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• 1996

Red alder(Alnus rubra Bong.) seedlings inoculated with Frankia only or both Frankia and spores of Alpova diplophloeus(Zeller & Dodge) Trappe & Smith were grown in a greenhouse for ten weeks. The ten-week-old seedlings were fertilized with six nitrogen(N) and phosphorus(P) fertility regimes (no fertilization, 10mM $NH_4NO_3$, 50mM $NH_4NO_3$, 5mM $KH_2PO_4$, 10mM $NH_4NO_3+5mM$ $KH_2PO_4$, and 50mM $NH_4NO_3+5mM$ $KH_2PO_4$) three times a week for ten weeks. The higher N-fertilization significantly increased mycorrhiza formation by greenhouse contaminant mycorrhizal fungi, but decreased N-fixation and P concentration in nodule tissues. P-fertilization significantly increased nodule and shoot dry weight, and P concentration in plant tissues. When N was highly fertilized, however, the P-fertilization effect disappeared in nodule P concentration but doubled in leaf P concentration. A. diplophloeus inoculation significantly increased diameter growth and $CO_2$ exchange rate, but decreased leaf dry weight. Our results suggest that the higher N- or P-fertilization affect nitrogenase activity and mycorrhizal development but the effects are changed by their interactions.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.162-167
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• 2012

The removal of orthophosphate ions from aqueous solutions by the anion exchange resin in the form of $Cl^-$ ion was investigated to elucidate the ion exchange mechanism which depends on the forms of orhthophoshate ions. In addition, the effects of alkalinity and other common anions were studied. The results showed that the orhthophosphate ions with the oxidation state of 2 and 3 ($HPO{_4}^{2-}$ and $PO{_4}^{3-}$) were effectively removed by the anion exchange resin, whereas the part of the $H_2PO_4{^-}$ ion passed through the ion exchange column. This suggested that the affinity of $H_2PO_4{^-}$ to the ion exchange resin was comparable with that of $Cl^-$ ion. In all cases, the effluent pHs have shown to be much lower than the calculated values, indicating that more $Cl^-$ ions than the orthophosphate equivalents in the influent were eluded. As the alkalinity increases, the decrease in pH was minimized. When the alkalinity was 100 mg/L ($CaCO_3$) or greater, 100 mg/L orthophosphate ions including $H_2PO_4{^-}$ were completely removed. The common anions such as $SO{_4}^{2-}$ and $NO_3{^-}$ were also removed by the anion exchange resin, and thus decreased the ion exchange capacity for the removal of orthophosphate.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1064-1071
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• 2022

Arabinogalactans have diverse biological properties and can be used as pharmaceutical agents. Most arabinogalactans are composed of β-(1→3)-galactan, so it is particularly important to identify β-1,3-galactanases that can selectively degrade them. In this study, a novel exo-β-1,3-galactanase, named PoGal3, was screened from Penicillium oxalicum sp. 68, and hetero-expressed in P. pastoris GS115 as a soluble protein. PoGal3 belongs to glycoside hydrolase family 43 (GH43) and has a 1,356-bp gene length that encodes 451 amino acids residues. To study the enzymatic properties and substrate selectivity of PoGal3, β-1,3-galactan (AG-P-I) from larch wood arabinogalactan (LWAG) was prepared and characterized by HPLC and NMR. Using AG-P-I as substrate, purified PoGal3 exhibited an optimal pH of 5.0 and temperature of 40℃. We also discovered that Zn²⁺ had the strongest promoting effect on enzyme activity, increasing it by 28.6%. Substrate specificity suggests that PoGal3 functions as an exo-β-1,3-galactanase, with its greatest catalytic activity observed on AG-P-I. Hydrolytic products of AG-P-I are mainly composed of galactose and β-1,6-galactobiose. In addition, PoGal3 can catalyze hydrolysis of LWAG to produce galacto-oligomers. PoGal3 is the first enzyme identified as an exo-β-1,3-galactanase that can be used in building glycan blocks of crucial glycoconjugates to assess their biological functions.