• Carbon letters
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• 제13권4호
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• pp.205-211
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• 2012

Methanol as a carbon source in chemical vapor deposition (CVD) graphene has an advantage over methane and hydrogen in that we can avoid optimizing an etching reagent condition. Since methanol itself can easily decompose into hydrocarbon and water (an etching reagent) at high temperatures [1], the pressure and the temperature of methanol are the only parameters we have to handle. In this study, synthetic conditions for highly crystalline and large area graphene have been optimized by adjusting pressure and temperature; the effect of each parameter was analyzed systematically by Raman, scanning electron microscope, transmission electron microscope, atomic force microscope, four-point-probe measurement, and UV-Vis. Defect density of graphene, represented by D/G ratio in Raman, decreased with increasing temperature and decreasing pressure; it negatively affected electrical conductivity. From our process and various analyses, methanol CVD growth for graphene has been found to be a safe, cheap, easy, and simple method to produce high quality, large area, and continuous graphene films.

• 대한미생물학회지
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• 제10권1호
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• pp.19-24
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• 1975

Anaerobic bacteria are the major residents of human skin and mucous membrane. The importance, as opportunistic pathogens, of anaerobic bacteria are well recognized because of more population. with decreased defense against bacterial invasion due to chemotherapy, rediation therapy, extensive surgical operation etc. are dealt at hospitals. An analysis of the anaerobe isolation results at Yonsei University Medical Center during the January 1974-May 1975 period was made and the following results were obtained. 1) From 118 patients 146 strains of anaerobes were isolated. Among these 81.3% were nonsporforming anaerobes. Most frequently isolated anaerobes were Pc. asaccharolyticus, Ps. anaerobius, Ps. intermedius, B. fragilis and Cl. perfringens. 2) Anaerobes were frequently isolated from wound, female genital, intraabdominal, and pleuropulmonary specimens. Fewer anaerobes were isolated from blood, spinal fluid and liver specimens. 3) The ratio of anaerobe isolation to total bacteria isolation were; liver 66.7%, intraabdominal 33.3%, pleuropulmonary 28.9%, spinal fluid 5.0% and blood 4.2%. 4) Among the 118 anaerobe isolated patients, 48.3% yielded anaerobes only and rest of them yielded anaerobes together with aerobes. 5) Most of the gram-positive anaerobes were susceptible to the antibiotics tested. Exception was to tetracycline to which appreciable number showed resistance. It was noteworthy that only 48% of B. fragilis was susceptible to tetracycline.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.390-390
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• 2011

The size distribution of gold nanoparticles (NPs) is an important factor in their application to various fields of nanotechnology such as nanodevice fabrication, nanobio measurements, medical diagnosis, and so on, since the properties of nanoparticles depend on the size. As the pH of the reaction mixture was increased, the size distribution of gold NPs synthesized via sodium citrate reduction method was getting narrower and it finally became quite mono-dispersive when the pH was higher than ca. 7. 0.1M NaOH solution was used in controlling the pH, while the ratio between sodium citrate and HAuCl4 was fixed to 3:1 whose initial pH was about 5. Scanning and tunneling electron microscopy and UV/Vis spectrometry were used to characterize the resulting Au NPs. The change of the size distribution of the NPs was discussed with the change of the reaction rate related to the change of hydroxyl ion concentration.

• 한국수산과학회지
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• 제23권5호
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• pp.401-406
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• 1990

In order to assess fish meal as food protein source which contains heat denatured pro-tein, functional properties of fish meal protein to be treated with alkaline were examined. Ratio of fish meal to 0.2N NaOH solution for extract solvent which were 1:10 showed good results of extracted and recovered amount of fish meal protein. pH 4.5, solubility of protein treated with alkaline revealed the lowest value. Until concentrations of alkaline treated protein solution reached $0.7\%$, its emulsifying capacity steeply decreased. Emusifying capacity of alkali treated protein were higher value at pH 9.0 than pH 4.0 and 7.0, and also were higher quantity in 0.5M NaCl solution than that of 0.1M. Heating time of fish meal protein to be treated with alkaline reached until 30 mins, its fat binding capacity indicated little change and that of heating time 60 mins decreased. Gel forming concentrations of fish meal protein to be treated with alkali for 15 mins or less were $20\%$ but those of 30 and 60 mins were $25\%$. When treating time of fish meal protein with alkali solution reached till 20 mins, viscosity of alkali treated protein solution steeply decreased.

• 한국세라믹학회지
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• 제39권7호
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• pp.642-648
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• 2002

본 연구에서는 TiCl$_4$를 가수분해 시켜 제조한 비정질의 titanium hydrous gel과 Ba(OH)$_2$.8$H_2O$를 출발물질로 사용하였으며, 반응용매로써 1,4-butanediol과 distilled water를 이용하여 나노 사이즈 BaTiO$_3$분말을 제조하였다. 용매로써 사용된 1,4-butanediol과 distilled water의 부피비에 따라 입자의 크기를 조절할 수 있으며, 습식화학법의 단점이었던 분말의 응집을 최소화 시킬 수 있다. 그리고 22$0^{\circ}C$의 비교적 낮은 반응온도에서 분산성이 우수하고, 입도분포가 좁은 약 50~200nm의 barium titanate 나노 분말을 제조하였다.

• Korean Chemical Engineering Research
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• 제54권2호
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• pp.229-233
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• 2016

본 연구에서는 식물세포배양액으로부터 파클리탁셀을 효율적으로 회수하기 위하여 초음파를 이용한 액-액 추출 공정을 개발하였다. 액-액 추출을 위한 최적의 초음파 파워와 조업 시간은 주어진 하층(메틸렌 클로라이드 층)/상층(메탄올 농축액 층) 비(25%, v/v)에서 각각 250W와 15 min임을 알 수 있었다. 최적 조건 하에서 초음파를 이용한 액-액 추출 공정의 경우 단 1 회 추출로 대부분의 파클리탁셀을 하층(메틸렌 클로라이드 층)으로부터 회수(~92%) 가능하였다. 또한 무기염 첨가에 의한 초음파 상승효과로 인하여 액-액 추출을 위하여 적절한 무기염 농도와 초음파 파워가 요구됨을 알 수 있었다.

• 한국가스학회지
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• 제4권2호
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• pp.27-32
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• 2000

본 연구는 염화망간과 수산화나트륨을 이용하여 당량비에 따라 산화망간을 합성하였다. 합성된 산화망간의 결정구조와 비표면적을 측정하였으며, 이산화탄소의 분해 및 흡착에 대하여 연구하였다. 합성된 시료의 결정구조 분석결과 $Mn_3O_4$의 주피크가 나타났으며, 약간의 $MnO_2$와 $Mn_5O_8$도 관찰되었다. 또한 비표면적은 $13.92m^2/g{\~}32.33m^2/g$으로 측정되었다. 산화망간을 이용하여 $450^{\circ}C$에서 이산화탄소의 분해를 실시하였으며, 당량비 0.75에서 가장 잘 분해되었다. 이산화탄소의 화학흡착량을 측정한 결과 2.885cc/g${\~}$19.628cc/g으로 관찰되었으며, 이산화탄소의 흡착을 위한 최적당량비는 1.00이었다.

• 한국수산과학회지
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• 제46권6호
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• pp.717-724
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• 2013

To characterize the food components of two mussels (wild hard-shelled mussel (HM) Mytilus coruscus, and cultured sea mussel (SM) Mytilus edulis) in Korea, we examined the proximate composition, fatty composition, amino acid/mineral content, texture, collagen content and chemical and taste compounds. Regarding the proximate composition, HM had lower moisture levels and higher crude protein and carbohydrate contents than SM. The amino nitrogen, volatile basic nitrogen and total amino acid contents of HM and SM were 250.6 and 227.3 mg/100 g, 11.2 and 12.0 mg/100 g, and 17,451.1 and 15,334.8 mg/100 g, respectively. The major amino acids were glutamic acid, aspartic acid, glycine, alanine, lysine and arginine. The major fatty acids of HM and SM were 14:0, 16:0, 16:1n-7, 20:5n-3, and 22:6n-3, which did not differ significantly between the two mussels. HM had a higher n-3 polyene ratio, and a lower saturate and monoene ratio than SM. Regarding the taste-active compounds, the free amino acid contents of HM and SM were 1,116.5 and 961.8 mg/100 g, respectively, and the major free amino acids were taurine, glutamic acid, glutamine, glycine, citrulline, lysine and arginine. The primary minerals in both HM and SM were Na, Cl, K and P which did not differ significantly between the two mussels. The soluble and insolube collagen contents of HM and SM were 265.8 and 228.4 mg/100 g, and 119.5 and 121.8 mg/100 g, respectively.

• 한국토양비료학회지
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• 제50권6호
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• pp.623-633
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• 2017

Food waste has been recognized as a organic sources for composting and many research was conducted to efficiently utilize or treat. This study was to evaluate a feasibility for producing food waste compost under co-composting with mixture of food and animal waste. The mixing ratio of food and animal waste was 35% as main material, which additionally mixed 30% of sawdust for co-composting. Total days of composting experiment were 84 days and each sub samples were collected at every 7 days from starting of composting. Results showed that inner temperature in composting was rapidly increased to $70{\pm}4^{\circ}C$ within 3~5 days depending on mixing animal waste of cattle, pig, and chicken base compared to sole food waste base. Expecially, the CN ratio in the mixture of food and pig water was the highest (16.2) among compost. After finishing composting experiment, maturity was evaluated with solvita and germination test. Maturity index (MI) of the mixture of food and animal waste was ranged between 6~7, but was 3 in sole food waste. Calculated germination index (GI) was at the range of about 100 irrespectively of mixing of food and animal waste. However, NaCl content and heavy metal as Cr, Cu, Ni, Pb, and Zn contents was increased in the mixture of food and animal waste. which was the highest in compost mixed the food and pig waste. Both MI and GI showed that manufactured fertilizer was suitable for fertilizer criteria while sole food waste was not adequate for composting due to composting periods. Overall, mixing the food and animal waste can be utilized for improving compost maturity, but more research should be conducted to make high quality of food waste compost with animal waste in agricultural fields.

• 콘크리트학회논문집
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• 제29권4호
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• pp.415-424
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• 2017

본 연구의 목적은 플라이애시 및 고로슬래그 미분말로 제조한 알칼리 활성화 결합재 모르타르의 황산염 저항성에 미치는 마그네슘(Magnesium, $Mg^{2+}$) 및 황산(Sulfate, ${SO_4}^{2-}$) 이온의 영향을 확인하는 것이다. 이를 위하여 고로슬래그 미분말 치환율을 30%, 50% 및 100%, $SiO_2$와 $Na_2O$의 몰 비($SiO_2/Na_2O$ molar ratio, Ms)를 1.0, 1.5 및 2.0으로 조정한 시험체를 제작하였다. 그리고 $Mg^{2+}$ 및 ${SO_4}^{2-}$의 영향을 확인하기 위하여 $Mg^{2+}$ 단독(10% $Mg(NO_3)_2$), ${SO_4}^{2-}$ 단독(10% $Na_2SO_4$), $Mg^{2+}$ 및 ${SO_4}^{2-}$ 복합(10% [$MgCl_2+Na_2SO_4$], 10% [$Mg(NO_3)_2+Na_2SO_4$]) 및 $MgSO_4$ 수용액(10%, 5% 및 2.5% $MgSO_4$)의 조건에서 압축강도, 길이변화, 질량변화 및 X선 회절 분석을 실시하였다. 그 결과, $Mg^{2+}$ 및 ${SO_4}^{2-}$가 공존하는 경우에만 황산염 침식에 의한 강도저하 및 팽창 등이 발생하는 것을 확인하였다. 이러한 현상은 $Mg^{2+}$이 규산칼슘 수화물(Calcium Silicate Hydrate, C-S-H)을 분해하여 $Ca^{2+}$이 용출되고, 용출된 $Ca^{2+}$과 ${SO_4}^{2-}$가 결합하여 석고($CaSO_4{\cdot}2H_2O$, Gypsum)를 생성하고, $Mg^{2+}$과 OH가 결합하여 수산화마그네슘(Magnesium hydroxide, $Mg(OH)_2$, Brucite)을 생성하는 것에 기인하는 것을 확인하였다.