• 한국안전학회지
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• 제27권6호
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• pp.59-63
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• 2012

The use of dry chemical powder has been increased as it can be stored for a long period and sustain in stable condition compared to gas or liquid phase extinguishing agents. A new type of dry chemical powder using Zeolite was produced in the research. Chemical powder was adsorbed into Zeolite 13X, a porous material appearing negative catalytic effect, to create extinguishing powder obtaining core shell structure and measured physical properties and run a small scale fire extinguishment. SEM, XRD, TA analysis was also executed, and extinguishing characteristics were measured by fire extinguishing experiment on oil pool fire. The experiment showed that the average particle size of Zeolite 13X was equivalent, indicating about $3{\pm}1{\mu}m$ and thermal analysis result illustrated that Zeolite 13X showed exothermic reaction peaks at $900^{\circ}C$ due to solid-state transformation. Extinguishing characteristics on oil fire of $NaHCO_3$/Zeolite 13X and $NH_4H_2PO_4$/Zeolite were improved, influenced by adsorbed extinguishing powders on Zeolite 13X and Zeolite 13X that contains high phase transition temperature.

• 한국가금학회지
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• 제15권3호
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• pp.219-227
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• 1988

본 실험은 사료첨가제로 사용되는 인산칼슘제에 들어있는 Ca과 P의 생물학적 이용성을 측정 비교하고자 실시하였다. 5일령의 수평아리를 사용하여 12 일간의 실험기간 후에 경골의 회분함량율 기준으로 하여 표준계선에 의한 least square방식으로 측정한 이용성의 결과는 다음과 같다. 1. P의 이용성은 DiCa-P첨가제가 각각 77.1, 91.0, 96.4 그리고 95.5％를 나타냈고 TriCa-P첨가제는 각각 94.1, 95.0 및 99.5％를 나타냈다. 2. Ca의 이용성은 DiCa-P 첨가제에서 각각 78.3, 234.1, 87.6 그리고 244.5％였고 TriCa-P첨가제는 각각 99.5, 84.0 및 101.5 ％였다. 3. 전반적으로 TriCa-P첨가제가 DiCa-P첨가제보다 이용성이 약간 높게 나타났다. 4. 국산과 외국산 인산칼슘제의 이용성의 차이는 없었다.

• 한국산림과학회지
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• 제55권1호
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• pp.37-46
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• 1982

대기오염중(大氣汚染中)에서도 임목(林木)에 가장 막대(莫大)한 피해(被害)를 주는 아류산(亞硫酸)gas($SO_2$)가 조경수목(造景樹木)에 미치는 피해(被害)와 대표적(代表的)인 몇가지 수종(樹種)에 있어서 이들간(間)에 내연성(耐煙性)의 차이(差異)를 알아 내어 조경수목(造景樹木)에 의(依)한 한국공업단지내(韓國工業團地內)의 공해방지(公害防止)를 위(爲)한 대책(對策)을 강구(强求)하고자 $Na_2SO_3+H_2SO_4{\rightarrow}Na_2SO_4+H_2O+SO_2{\uparrow}$의 반응식(反應式)을 응용(應用)하여 조사관찰(調査觀察)하였던바 다음과 같은 결과(結果)를 얻었다. 1) 한국(韓國)의 공업단지중(工業團地中) 과반수이상(過半數以上)의 공장(工場)을 점유(占有)하고 있는 특(特)히 남부지역(南部地域)을 중심(中心)으로 울산시(蔚山市)와 창원시(昌原市) 그리고 포항시(浦項市)의 조경(造景) 및 가로수(街路樹)는 모두 51종(種) 161,699본(本)이었으며 그중(中)에서도 가장 다수(多數)를 점(占)하고 있는 수종(樹種)은 현사시나무, 회양목, 개나리, 향나무, 소나무등(等)의 5종(種)이었다. 2) 각수종(各樹種)에 있어서 $SO_2$의 농도(濃度)와 피해율(被害率)과의 관계(關係)를 조사(調査)해 보면 비교적(比較的) 저농도(低濃度)의 경우에는 급격(急激)히 세포(細胞)의 파괴량(破壞量)이 많아지지 않으며 농도(濃度)가 증가(增加)함에 따라 직선적(直線的)으로 피해율(被害率)이 증가(增加)하였다. 3) 농도별(濃度別) 피해도(被害度)에 대(對)한 차이(差異)는 5종(種)의 수목중(樹木中)에서 회양목이 제일강(第一强)하였고 그 다음이 현사시나무, 개나리, 향나무, 소나무의 순위(順位)로서 소나무가 제일약(第一弱)하였다. 4) 차후(次後)로 공업단지(工業團地)의 조경(造景) 및 가로수목(街路樹木)은 침엽수(針葉樹)보다는 활엽수(闊葉樹)로서 상록다육엽(常綠多肉葉)이면서 맹아력(萌芽力)과 내화력(耐火力)이 강(强)한 수종(樹種)으로 점차(漸次) 개식(改植)할 필요(必要)가 있다. 5) 공단도시(工團都市)의 도시림조성면적(都市林造成面積)은 1인당(人當) $50m^2$정도(程度)는 필요(必要)하며 공장지대(工場地帶)와 주택지대간(住宅地帶間)에는 100m폭(幅) 정도(程度)의 녹지지대(綠地地帶)를 조성(造成)할 필요(必要)가 있다.

• Journal of Preventive Medicine and Public Health
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• 제18권1호
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• pp.59-71
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• 1985

During a period from February 1st to November 30th in 1983, measurements were made twice a month on dustfalls and concentrations of various cations ana anions in their filtrates in an urban (Heuksuk-dong, Seoul) and in a rural (Ansung) districts. Standard British Deposit Gauge method was applied for collection of dustfalls and ion chromatographic method using Ion Chromatograph 10 (Dionex, U.S.A.) for determination of cation and anion concentrations. The results obtained were as follows: 1. Annual mean values of dustfalls were $8.30{\pm}5.09tons/km^2/month$ in an urban and $6.20{\pm}0.82tons/km^2/month$ in a rural districts. And annual mean values of pH of filtrates of the collected samples were $5.3{\pm}0.76$ in an urban and $6.0{\pm}0.82$ in a rural districts. 2. Annual mean concentrations of common cations and anions in their filtrates were as follows: urban rural (unit: ppm) $$Na^{+}\;1.7{\pm}1.30\;1.9{\pm}1.86$$ $$NH^{+}_{4}\;2.4{\pm}1.60\;1.3{\pm}1.59$$ $$K^{+}\;0.7{\pm}0.47\;1.5{\pm}3.79$$ $$Ca^{++}\;5.3{\pm}0.95\;3.4{\pm}2.58$$ $$Mg^{++}\;0.7{\pm}0.89\;0.5{\pm}0.83$$ $$Cl^{-}\;2.0{\pm}1.31\;4.0{\pm}2.35$$ $$NO^{-}_{3}\;4.0{\pm}2.35\;2.7{\pm}1.31$$ $$So^{--}_{4}\;16.9{\pm}17.40\;6.8{\pm}8.00$$ Some of anions such as $Br^{-},\;{PO_4}^{-3}\;and\;{NO_2}^{-}$ were scarecely detected and $F^{-}$ was measured at very low concentrations ranging from 0.1 to 0.5 ppm in Feb., Oct. and Nov. in an urban and in Feb. in a rural districts. 3. By two-way analysis of variance with 4 replications for dustfalls, pH and concentrations of various ion by district and month of a year, statistically significant differences were noted in dustfalls (p<0.01), pH (p<0.01) and concentrations of various ion (p<0.01) by month of a year, and in dustfalls (p<0.05) and concentrations of various ion such as ${NH_4}^{+},\;Ca^{++},\;{NO_{3}}^{-}\;and\;{SO_4}^{--}$ (p<0.01) by district. 4. There were statistically significant differences pH in Spring (Feb., Mar and Apr.) (p<0.01) and in ${SO_4}^{--}$ in Autumn (Aug., Sept., Oct. and Nov.) (p<0.05) between the two districts.

• 상하수도학회지
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• 제29권2호
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• pp.261-269
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• 2015

In this study, we applied a membrane distillation process to investigate a feasibility of treating a wastewater with high concentration of organic matters including nitrogen and phosphorus. The laboratory scale experiment was performed by using a hydrophobic PVDF membrane with the pore size of $0.22{\mu}m$ and porosity of 75%. The installation was direct contact type where the temperature difference between a feed and permeate side was controlled to have a range from 20 to $60^{\circ}C$. We observed a flux variation and a concentration changes of COD, $PO{_4}^{3-}$-P, $NH_4{^+}$-N and conductivity of feed side as well as permeate side with various temperature differences (20 to $60^{\circ}C$), cross flow velocities (0.09 to 0.27 m/s) through the module, and pH (6.6 to 12.0) of the feed that has the initial concentration of COD about 1,000 mg/L, total nitrogen 390 mg/L, total phosphorus 10 mg/L, conductivity of $7,000{\mu}s/cm$. The results showed that the average flux was ranged from 4 to $40L/m^2/hr$ which was almost similar with the flux of NaCl and deionized water used as a feed solution. The lowest flux was obtained at the operating condition with the temperature difference of $20^{\circ}C$ and cross flow velocity of 0.09 m/s while the highest one was measured with $60^{\circ}C$ and 0.27 m/s. Above 99% of COD and $PO{_4}^{3-}$-P in the feed could be rejected regardless of an operating condition. However, the removal rate of ammonium nitrogen was varied from 64 to 99% depending on the pH of feed solution.

• 한국응용과학기술학회지
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• 제32권4호
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• pp.758-766
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• 2015

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

• KSBB Journal
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• 제11권2호
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• pp.246-253
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• 1996

생분해성 고분자의 생산 단가를 낮추기 위해 값싼 원료인 LNG와 강제성 메탄자화균인 M. tricha­s sparium OS3b를 이용하여 PHS 생산 가능성을 검토하였다. 중요한 결과를 요약하면 다음과 같다. 1. 산업용 기질인 LNG를 에탄 원료로 사용한 경 우 LNG 중의 에탄과 프로판에 의해 비성장 속도가 감소하였으내(저해상수 $K_1=0.12%$) PHS 생성에는 영향을 주지 않았다. 2. 배양액 중 구리 이온이 결핍되면 PHS 축적은 현저히 감소하였다. 3. 각종 영양원 결핍조건에서 PHS 축적능을 시험 하였을 때, 칼륨, 마그네숨, 그리고 질소원 결핍이 높은 PHS 축적율을 보였고, 특히 질소원의 경우 최 고 45%의 축적율을 보였다. 4. 최척의 질소원/탄소원의 비는 존재하지 않았고, 질소원의 농도가 낯을수록 PHS 축적율은 증가 하였다. 5. PHS 축척을 위한 최적 온도와 pH는 각각 $30^{\circ}C$와 7.0이었다.

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.180-186
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• 1998

A 10-week feeding experiment was conducted to determine the phosphorus requirement of juvenile Korean rockfish (Sebastes schlegeli). Three replicate groups of fish initially averaging 4.2g were fed the semipurified experimental diets containing graded levels of $NaH_2PO_4\;\cdot\;2H_2O$ to provide from $0.1\%$ to $1.32\%$ total phosphorus level in a flow-through seawater system. Korean rockfish muscle and casein were used as the protein sources of the basal diet. Weight gain, feed efficiency and protein retention of fish fed the $0.35\%$ phosphorus were higher than those of fish fed the $0.1\%$ phosphorus, although no significant improvements $(P>0.01)$ were observed above the level. Determined phosphorus requirement using the broken line model was found to be $0.3\%$ for weight gain. Moisture, protein and lipid contents of whole body and muscle were not affected by dietary phosphorus levels $(P>0.01)$. Lipid contents of liver in fish fed the $0.1\%$ phosphorus were lower than those in fish fed the $0.35\%$ and $1.32\%$ phosphorus $(P<0.01)$. Dietary phosphorus increased ash and phosphorus contents of the whole body, while those of bone were not affected $(P>0.01)$. The data obtained in this study indicate that a $0.3\%$ dietaryphosphorus level could be recommended for the optimum growth and efficient nutrient utilization of juvenile Korean rockfish.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.79-80
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• 2013

The purpose of this study was to investigate $2^{nd} $nanotube formed surface observation of the Ti-25Ta-xZr alloys using ATO(anodic titanium oxide) technique. Ti-25Ta-xZr alloy was anodized in 1M $H_3PO_4$ electrolytes containing 0.8 Wt. % NaF at room temperature. After formation of nanotube was achieved out, nanotube was eliminated, and then anodization was carried out repeatedly. The microstructures, phase transformation, and morphology of nanotubular Ti-25Ta-xZr alloys and process of nanotube growth by using ATO method was examined by optical microscopy (OM), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The ${\alpha}$ phase and ${\beta}$ phases were affected to form the second nanotube morphology of Ti-25Ta-xZr alloys.

• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.496-502
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• 2015

Polyketide secondary metabolites share common precursor pools, acyl-CoA. Thus, the effects of engineering strategies for heterologous and native secondary metabolite production are often determined by the measurement of pikromycin in Streptomyces venezuelae. It is hard to compare the effectiveness of engineering targets among published data owing to the different pikromycin production media used from one study to the other. To determine the most important nutritional factor and establish optimal culture conditions, medium optimization of pikromycin from Streptomyces venezuelae ATCC 15439 was studied with a statistical method, Plackett-Burman design. Nine variables (glucose, sucrose, peptone, (NH₄)₂SO₄, K₂HPO₄, KH₂PO₄, NaCl, MgSO₄·7H₂O, and CaCO₃) were analyzed for their effects on a response, pikromycin. Glucose, K₂HPO₄, and CaCO₃ were determined to be the most significant factors. The path of the steepest ascent and response surface methodology about the three selected components were performed to study interactions among the three factors, and the fine-tune concentrations for maximized product yields. The significant variables and optimal concentrations were 139 g/1 sucrose, 5.29 g/l K₂HPO₄, and 0.081 g/l CaCO₃, with the maximal pikromycin yield of 35.5 mg/l. Increases of the antibiotics production by 1.45-fold, 1.3-fold, and 1.98-fold, compared with unoptimized medium and two other pikromycin production media SCM and SGGP, respectively, were achieved.