• 방사성폐기물학회지
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• 제7권1호
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• pp.33-38
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• 2009

신선한 흑운모 및 인위적으로 풍화시킨 흑운모에 대한 우라늄 수착 실험을 실시하였다. 실험 이후, 원심분리하여 상등액은 유도결합플라즈마분광분석(ICP-MS)으로 우라늄 농도를 분석하였고, 고체시료는 X-선 회절분석(XRD) 및 주사전자현미경(SEM) 분석을 실시하였다. 3 mm 이하의 흑운모 시료를 7개월 간 실험실에서 풍화시킨 후, 신선한 흑운모와 동일한 조건으로 pH 변화에 따른 우라늄 수착량을 구하였다. 낮은 pH(pH 3)에서는 흑운모에 대한 우라늄의 수착이 크지 않았지만, pH가 증가함에 따라 점차 우라늄 수착이 증가하는 경향을 보였다. 풍화된 흑운모의 우라늄 수착량은 신선한 흑운모에 비해 작았고 높은 pH(pH 11)에서는 그 차이가 더 심하였다. 풍화된 흑운모의 낮은 우라늄 수착특성은 광물 표면의 변화 및 주위 용존이온들의 화학적 거동에 의한 것으로 보인다. 풍화된 흑운모 시료에는 광물 표면에서 선호되는 흡착자리가 파괴되거나 용해되고 더불어 용존 이온들의 콜로이드화에 의해 우라늄-광물 표면 수착반응이 감소되는 것으로 보인다.

• 한국환경과학회지
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• 제7권5호
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• pp.623-631
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• 1998

Pyrite contained in wasted ore dumps induces a strong acid environment when it contacts oxygenated rainfall. Present research was designed to evaluate the pollution of an area that is supposedly contaminated by pyrite of ore wasted dumps form in Chonju Il Mine. Measured are the pH and selected heavy metal elements in the supposedly polluted hydrologic system. The samples include three types : those collected from the stream waters; those from the stream sediments; and those from the rice field soil scattered over the area. The dispersion path of the pollution source was also traced. The pH of the hydrologic system ranged from 3.44 to 5.46, which clearly indicates that the area is on the acid environment. The pH tends to rise as the distance from the minehead increases. The content of heavy metal elements dissolved in the stream water varies as follows; Mn=69.73~1.99ppm, Cd=0.02~0.03ppm, Zn=0.77~1.18ppm, Cu=0.04~0.13ppm, Pb=0.22~0.32ppm. The stream water in this state may induce serious heavy metal pollution to the agricultural land and the water for human life especially in the villages down the stream. The content of heavy metal elements dissolved in the stream sediment varies as follows; Mn=245.0~4685.0ppm, Cd=10.0~15.0ppm, Zn=105.0~210.0ppm, Cu=65.0~155.0ppm, Pb=90.0~150.0ppm. The content of heavy metal elements dissolved in the rice field soil varies as follows; Mn=185.0~260.0ppm, Cd=10.0~15.0ppm, Zn=135.0~180.0ppm, Cu=65.0~90.0ppm, Pb=100.0~130.0ppm. The pollution index in the stream sediment and the rice field sell is 1.36~2.03, which shows that pollution had already begun all over the area where the samples were collected.

• Membrane and Water Treatment
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• 제9권3호
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• pp.181-188
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• 2018

A sidestream contains the filtrate or concentrate from the belt filter press, filter backwash and supernatant from sludge digesters. The sidestream flow, which heads back into the sewage treatment train, is about 1-3% less than the influent flow. However, the sidestream can increase the nutrient load since it contains high concentrations of phosphorus and nitrogen. In this study, the removal of PO4-P with organic matter characteristics and bacteriological changes during the sidestream treatment via ladle furnace (LF) slag was investigated. The sidestream used in this study consisted of 11-14% PO4-P and 3.2-3.6% soluble chemical oxygen demand in influent loading rates. LF slag, which had a relatively high $Ca^{2+}$ release compared to other slags, was used to remove $PO_4-P$ from the sidestream. The phosphate removal rates increased as the slag particle size decreased 19.1% (2.0-4.0 mm, 25.2% (1.0-2.0 mm) and 79.9% (0.5-1.0 mm). The removal rates of dissolved organic carbon, soluble chemical oxygen demand, color and aromatic organic matter ($UV_{254}$) were 17.6, 41.7, 90.2 and 77.3%, respectively. Fluorescence excitation-emission matrices and liquid chromatography-organic carbon detection demonstrated that the sidestream treatment via LF slag was effective in the removal of biopolymers. However, the removal of dissolved organic matter was not significant during the treatment. The intact bacterial biomass decreased from $1.64{\times}10^8cells/mL$ to $1.05{\times}10^8cells/mL$. The use of LF slag was effective for the removal of phosphate and the removal efficiency of phosphate was greater than 80% for up to 100 bed volumes.

• 한국수산과학회지
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• 제40권1호
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• pp.39-49
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• 2007

Species competition among the toxic dinoflagellates Alexandrium tamarense and Gymnodinium catenatum and the diatom Skeletonema costatum was simulated using a mathematical model. Prior to the model simulation competition experiments using the three species were conducted to obtain data for validation by the simulation model. S. costatum dominated at a density of ${\sim}10^{4}\;cells/mL$ compared to the other species in the medium with dissolved inorganic phosphorus (DIP). The growth of S. costatum was also stimulated by the addition of dissolved organic phosphorus (DOP), such as uridine-5-monophosphate (UMP) or glycerophosphate (Glycero-P), although this species is unable to take up DOP. This implies that the growth of S. costatum may be supported by DIP, which is hydrolyzed by alkaline phosphatase produced from A. tamarense and G. catenatum. The species competition model was run assuming the environmental conditions of northern Hiroshima Bay, Japan, during spring and summer. G. catenatum increased in cell density and neared the level of S. costatum at the end of the calculation. In the sensitivity analyses by means of doubling and halving parameters, depleted DIP had little effect on the cell density of G. catenatum. However the growth of A. tamarense and S. costatum was significantly affected by changes in the parameter values. These results indicate that if DIP depletion is ongoing, species that have a large phosphate pool in their cells, such as G. catenatum, will predominate in the community.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
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• pp.254-258
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• 1999

The distribution of anionic groups in the fibers, the fines, the colloidal fraction and the dissolved fraction, respectively, of thermomechanical pulp (TMP) suspensions was determined and peroxide bleaching of spruce TMP were also studied. Spruce TMP was extracted with hexane, treated with alkali, or bleached with peroxide. Suspensions made at pH 5.5 were fractionated into long fibres, large fines, small fines, a colloidal fraction and a dissolved fraction. The charge of the fractions was determined using polyelectrolyte titration. To determined the origin of the charges, the contents of fatty acids, resin acids and acidic units in hemicelluloses in the different fractions were determined by has chromatography. Extraction of TMP with hexane prior to fractionation increased the measured charge of the fibres. The removal of the wood resin probably uncovered some carboxyl groups on the fibre surfaces, or improved th e penetration of polybrene into the pores of the fibres. The charge of the fines and the colloidal fraction was lower when the wood resin had been removed. Alkaline treatment of the TMP increased the charge of the fibres and fines, mainly because of demethylation of pectins. Alkaline treatment increased the charge also of the dissolved fraction, because of the release the charge also of the dissolved fraction, because of the release of pectic acids into the water phase. Alkaline peroxide bleaching further increased the charge of fibres and the dissolved fraction, most likely because of lignin oxidation. The charge of the colloidal fraction, consisting mainly of wood resin, was only slightly affected by alkaline treatment and peroxide bleaching. The anionic groups in TMP suspensions were mainly free uronic acids in the hemicelluloses. The contribution from the fatty and resin acids was substantial only for the colloidal fraction.

• ALGAE
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• 제18권4호
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• pp.281-288
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• 2003

To study the environmental features causing a bloom of the novel dinoflagellate Heterocapsa circularisquama (Dinophyceae), hydrographic and chemical aspects were measured in the Uranouchi Bay, Kochi Prefecture, Japan, from January to December, 1997. The cell density of H. circularisquama increased rapidly in early October, and dropped sharply in mid-October. Growth rate of H, circularisquama during bloom period appeared 1.50 division day$^{-1}$ under high water temperature (25$^{\circ}C$) and salinity (32 psu) conditions. Althought the result from hydrographic aspect indicated good condition for their growth, dissolved inorganic phosphorus (DIP) concentration in surface layer before bloom formation was less than 0.70uM, which is lower than their half saturation constant(Ks). Dissolved inorganic nitrogen(DIN): DIP ratio was > 30, indicating potential P-limitation. However, before bloom formation period of H. circularisquama, DIP concentrations were high in bottom layer (> 4.0 uM). Some studies reported that H. circularisquama had the ability to migrate vertically and to utilize dissolved organic phosphorus (DOP). Thus, DIP in bottom layer might have been utilized by H. circularisquama for their growth.DOP might have weakly affected their growth because of low reactive DOP concentrations owing to low DOP concentration (ca. 0.39 uM). Thus, if nutrient condition of bottom layer in Uranuchi Bay is not improved, the outbreaks of H. circularisquama red tides may became an annual feature.

• 한국포장학회지
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• 제18권1_2호
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• pp.21-25
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• 2012

본 연구는 레토르트 삼계탕 제품에서 육수의 충진 포장온도가 저장 중 품질과 저장 수명에 미치는 영향을 조사하기 위하여 수행되었다. 공시 레토르트 삼계탕은 육수 충진 온도를 $50^{\circ}C$(T1)와 $85^{\circ}C$(T2)로 달리하여 포장한 후 $120^{\circ}C$에서 65분간 F값 약 8.0의 조건으로 멸균하여 제조되었다. 시료들은 $25^{\circ}C$에서 6개월간 저장하며 0, 1, 3과 6개월차에 pH, 육수 내 용존산소량, 포장의 헤드스페이스 내 산소농도 비율, 산가, VBN, 점도, 관능검사와 퍼짐성에 대하여 분석되었다. 저장기간 중 T2는 T1에 비하여 VBN, 육수 내 용존산소량과 산가가 서서히 증가하는 경향을 보였다. 즉, pH와 육수 내 용존산소는 저장 초기부터, VBN값, 그리고 헤드스페이스 산소농도 비율과 산가는 3개월 후부터 양 처리구간 간에 유의적인 차이를 보였다(p<0.05). 반면, 저장기간 중 두 시료 간 점도, 퍼짐성과 관능검사 결과에서는 유의적 차이를 보이지 않았다(p>0.05). 본 연구결과, 레토르트 삼계탕에서 육수의 충진온도 차이는 관능적 변화에 미치는 영향은 6개월까지 저장하는 동안 통계학적으로 인정되지 않는 수준이었다. 그러나 본 실험이 6개월간 비교적 단기간 이루어진 동안에도 T2에서 T1보다 산가와 VBN값의 증가를 지연시키고 용존산소량을 낮추는 효과가 확인되었다(p<0.05). 결론적으로 레토르트 삼계탕의 품질 변화 최소화 및 장기 저장을 위해서는 육수 충진 시 $85^{\circ}C$ 이상 높여 포장하는 것이 바람직하겠다.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.1-7
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• 2002

The effects of DO and pH on the mass production of pullulan with high molecular weight and the morphology of A. pullulans ATCC 42023 were evaluated. A. pullulans showed a maximum production of pullulan (11.98 g/l) when the initial pH of the culture broth was 6.5 in a shake-flask culture. In a batch culture, the mixture of a yeast-like and mycelial cell forms was found at a pH of 4.5, and the maximum production of pullulan (13.31 g/l) was obtained. However, a high proportion of high molecular weight pullulan (M.W.>2,000,000) was produced at a pH of 6.5, with a yeast-like morphology. The maximum pullulan production yield ($51\%$) was obtained at a pH noncontrol (initial pH 6.5) and DO control (above $50\%$) condition. Pullulan degrading enzyme was activated when the pH of the broth was lower than 5.0 and the portion of low molecular weight pullulan was increased. The formation of a black pigment was observed at an initial stationary phase, at 40 h of fermentation. Therefore, the fermentation should be carried out in a pH noncontrol (initial pH of 6.5) and DO control (above $50\%$) condition, and should be harvested before reaching the stationary phase (around 40 h) for the production of high molecular weight pullulan.

• 한국식품영양학회지
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• 제25권1호
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• pp.90-98
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• 2012

동과착즙액에 에탄올을 가해 초산발효시켜서 산도 5.0%의 식초를 만들고, 여기에 구절초 추출액(농도 10%)을 10%를 가한 다음, 조개껍질을 녹여서 식초를 제조하였다. 동과 식초에 대하여 꼬막껍질, 굴껍질, 전복껍질을 1% 가하면 97.2~98.4% 녹고, 2% 가하면 95.8~95.6% 녹았다. 조개껍질을 1% 녹인 식초의 산도는 3.00~3.17, 2% 녹인 것은 1.11~1.20였고, 조개껍질을 1% 녹인 식초의 pH는 4.54~4.55, 2% 녹인 식초는 4.86~4.95로 조개껍질 1%짜리의 경우 시판 식초보다 산도가 높으면서도 pH 수치가 높아서 유리산이 적었다. 초산발효시 구절초를 가하면 1%일 경우 저해율 44.4%, 0.12%일 경우 저해율 22.2%을 나타내므로 구절초는 초산발효 후 첨가해야 한다. 조개껍질 1% 식초의 칼슘함량은 0.4%, 2% 식초는 0.78%였다. 열처리하지 않은 동과는 angiotensin 전환효소 저해활성 21.7%, 항산화효소 활성 5.23%, 티로시나제 저해활성 5.5%를 나타냈고, 열처리 추출 동과는 angiotensin 전환효소 저해활성 16.1%, superoxide dismutase 활성 20.5%, 항산화 활성 23.2%, 티로시나제 저해활성 7.1%를 나타냈다. 구절초는 angiotensin 전환효소 저해활성 28.8%, xanthine oxidase 저해활성 28.2%, speroxide dismutase 활성 14.5%, 항산화 활성 3.2%, 티로시나제 저해활성 9.2%로 나타났다. 10% 시료를 인간폐암상피세포주 A549 세포에 가한 결과, 세포는 동과가열추출액의 경우, 72시간에 80%, 생동과는 48시간 뒤에 74%, 구절초 가열 추출액은 72시간 뒤에 100% 암세포를 감소시켜 항암작용을 나타냈다.

• 한국환경과학회지
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• 제17권6호
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• pp.611-621
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• 2008

This study intends to provide the necessary basic data needed for predicting the water quality and examining changes in water quality on the basis of the hydrological changes: an outflow or the character of a flow by investigating the interaction of the parameters through the estimation of optimal parameters need for predicting the water quality of the dam basin and the sensitivity among those estimated parameters. Im-Ha Dam in the upstream area of the Nakdong River was selected for analysis, and the water quality survey data necessary for parameter estimation was based on the monthly water quality data (water temperature, BOD, T-N and T-P) between December 1, $2005{\sim}$November 31, 2006. K1C(the saturated growth rate of plant plankton), K1RC (endogenous respiratory quotient of plankton), KDC(deoxidized ratio), K71C(minealized ratio of dissolved organic phosphorus), K83C(mineralized ratio of dissolved organic nitrogen) have been considered as the factors of the water quality performed in this water quality simulation, that is, the most effective parameters on BOD, T-N and T-P. In the result of the analysis of the sensitivity, KDC(deoxidized ratio) was the most sensitively reacted parameter on BOD and it was K71C(mineralized ratio of dissolved organic phosphorus) and K83C(mineralized ratio of dissolved organic nitrogen) on T-N and T-P. It is considered that it will be possible to apply the most optimal parameter to an analysis of the water quality simulation at Im-Ha Ho basin in the goal year by examining the interaction of the parameters through the parameters sampling which are able to applicable to prediction of the water quality and the analysis of the its sensitivity, in the future, also the analysis on the basis of the hydrological conditions: an outflow or the character of a flow will be needed.