• 한국미생물·생명공학회지
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• 제22권3호
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• pp.296-303
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• 1994

An immobilized Trigonopsis variabilis cells having an high activity of D-amino acid oxidase(DAO) was used to convert CPC into GL-7-ACA. The optimal pH of the reaction system was 8.0-8.5, and the optimal temperature was 40$\circ$C. When immobilized cell was used repeatedly in semi-batchwise reaction, the system retained 80% of the initial activity after used of 12 times for over 12 hours. The storage stability of the immobilized cell was maintained for 30 days at 4$\circ$C. The CPC concentration for the maximal reaction rate was about 30 mM and 40 mM for free and immobilized cells, respectively. Substrate inhibition of CPC concentration more than 50 mM was overcomed by 20~25% by immobilization. Pure oxygen supply into reaction system was most efficient in D-amino acid oxidase reaction. Continuous conversion to GL-7-ACA from CPC has been developed with an bioreactor system containing immobilized T variabilis cells. By opera- tion of the reactor for 5 hours, the average conversion yield of >80% and GL-7-ACA production of 40~45 mM per hour could be obtained.

• 한국정밀공학회지
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• 제28권10호
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• pp.1217-1223
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• 2011

In this paper, the dielectric barrier discharge plasma generator has been studied for producing of the high concentration ozone gas. Proposed plasma generator has the structure of extremely narrow discharge air gap(0.15mm) in order to realize the high electric field discharge. We investigate the performance of the dielectric barrier discharge plasma generator experimentally and the results show that the generator has very high ozone concentration characteristics of 13.7[wt%/$O_2$] at the oxygen flow rate of 1[${\ell}$/min] of each discharge cell. So, we confirmed that the proposed plasma generator is suitable for the high concentration ozone production facility of the eco-friendly ozone functional water cleaning system in the electronic components cleaning process.

• 대한화학회지
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• 제21권6호
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• pp.449-452
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• 1977

脂質 生産의 새로운 供給源으로 고려될 수 있는 石油炭化水素 醱酵에 의한 菌體脂質의 生成에 있어서 炭化水素의 炭素數의 影響과 그 脂肪酸의 組成을 檢討하였다. 菌株로서 Rhodotorula sp., 基質로서 炭素數가 짝수인 n-tetradecane과 n-hexadecane을 使用하여 容量 2l의 醱酵槽에서 溫度 $28^{\circ}C$, pH 4.0 ∼ 4.6, 酸素供給速度 0.4vvm, 攪拌速度 1000 rpm의 條件에서 醱酵시켜 生成된 菌體를 回收, 乾燥後 菌體脂質을 抽出하고 gas-liquid chromatography로 醱酵酸 組成을 檢索한 바, n-tetradecane과 n-hexadecane을 基質로 한 경우, 生成菌體의 脂質含量은 各各 12.0 및 25,8 %이었으며 菌體 脂肪酸은 大部分 炭素數가 짝수인 脂肪酸으로 構成되어 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.926-929
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• 2007

A significant progress has been made in the characterization of zinc oxide (ZnO) semiconductor as a new semiconductor layer instead of amorphous Si semiconductor used in thin film transistor due to its high electron mobility at low deposition temperature which is quite suitable for flexible display and OLED devices. The wet pattering of ZnO is another important issue with regard to mass production of ZnO thin film transistor device. However, the wet behavior of ZnO thin film in aqueous wet etching solutions conventionally used un TFT industry has not been reported yet, in this work, wet corrosion behavior of RF magnetron sputtered ZnO thin film in various wet solutions such as phosphoric and nitric acid solutions was studied using by electrochemical analysis. The effects of deposition parameters such as RF power and oxygen partial pressure on corrosion rate are also examined.

• 대한기계학회논문집B
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• 제32권8호
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• pp.636-644
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• 2008

The objective of this paper is to investigate characteristics of an autothermal reformer at various operating conditions. Numerical method has been used, and simulation model has been developed for the analysis. Pseudo-homogeneous model is incorporated because the reactor is filled with catalysts of a packed-bed type. Dominant chemical reactions are Full Combustion reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction, and Direct Steam Reforming(DSR) reaction. Simulation results are compared with experimental results for code validation. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio(OCR), Steam to Carbon Ratio(SCR), and Gas Hourly Space Velocity(GHSV). Temperature at the reactor center, fuel conversion, species at the reformer outlet, and reforming efficiency are shown as simulation results. SR reaction rate is improved by increased inlet temperature. Reforming efficiency and fuel conversion reached the maximum at 0.7 of OCR. SR reaction and WGS reaction are activated as SCR increases. When GHSV is increased, reforming efficiency increases but pressure drop from the increased GHSV may decrease the system efficiency.

• 약학회지
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• 제37권1호
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• pp.84-88
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• 1993

Brovincamine is a selective cerebral vasodilator that was apparently produced via a slow calcium blockade. Brovincamine has been shown to increase ATP production and glucose and oxygen consumption in brain, improving energy metabolism. Also brovincamine inhibited platelet aggregation induced by ADP and collagen in vivo and in vitro via an increase of cAMP concentration, promoting therapeutic effects on cerebral circulatory disorders. So we investigated and represented the clinical effects and safety of brovincamine in patients with cerebral stroke. Thirty patients of cerebral stroke that was older than 2 months, who were 22 cases of cerebral infarction, 6 of cerebral embolism that originated from carebral infarction, 6 of cerebral embolism that originated from cardiac diseases, and 2 of cerebral embolism that originated from cardiac diseases, and 2 of cerebral hemorrhage, were administered of 20 mg of oral brovincamine three times daily for 8 weeks. Improvement rates of each symptom after 8 week administration were 30.8% for subjective symptoms, 76% for psychiatric symptoms and 65.6% for neurologic symptoms. In final global improvement rates, much improvement was 10%, improvement was 23.3% slight improvement is 36.7%, and no change was 30%. So global improvement rate including slight improvement was 70%. As for side effects, there were 3 cases of mild gastrointestinal symptoms, but there were no other subjective side effects and significant fluctuation in laboratory examination. Conclusively throughout the present study, brovincamine is judged to be well tolerated and effective in patients with cerebral stroke.

• Carbon letters
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• 제27권
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• pp.81-89
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• 2018

The present study aimed to prepare a novel efficient flame retardant additive for polypropylene. The new flame retardant was prepared by chemical grafting of melamine to graphene oxide with the aid of thionyl chloride. Fourier-transform infrared spectroscopy and thermogravimetric analysis proved that melamine had been successfully grafted to the graphene oxide. The modified graphene oxide was incorporated into polypropylene via solution mixing followed by anti-solvent precipitatio. Homogeneous distribution as well as exfoliation of the nanoplatelets in the polymer matrix was observed using transmission electron microscopy. Thermogravimetric analysis showed a significant improvement in the thermo-oxidative stability of the polymer after incorporating 2 wt% of the modified graphene oxide. The modified graphene oxide also enhanced the limiting oxygen index of the polymer. However, the amount of improvement was not enough for the polymer to be ranked as a self-extinguishing material. Cone calorimetry showed that incorporating 2 wt% of the modified graphene oxide lowered total heat release and the average production rate of carbon monoxide during burning of the polymer by as much as 40 and 35%, respectively. Hence, it was concluded that the new flame retardant can retard burning of the polymer efficiently and profoundly reduce suffocation risk of exposure to burning polymer byproducts.

• 상하수도학회지
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• 제38권1호
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• pp.29-38
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• 2024

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.

• 한국화재소방학회논문지
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• 제30권4호
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• pp.65-72
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• 2016

이 연구는 비스-(디메틸아미노메틸) 포스핀산(DMDAP), 비스-(디에틸아미노메틸) 포스핀산(DEDAP) 과 비스-(디부틸아미노메틸) 포스핀산(DBDAP)으로 처리된 리기다소나무의 연소 독성 가스의 생성에 관하여 조사하였다. 리기다소나무는 15 wt.% 방염제 수용액으로 3번 붓칠 한 후 상온에서 건조하였다. 연소 독성 기체의 생성물은 콘칼로리미터(ISO 5660-1)를 사용하여 조사하였다. 화학 첨가제로 처리된 첫 번째 피크 질량손실속도($1^{st}-TMLR_{peak}$) 시간은 처리하지 않은 시편과 비교하여 5.9%와 41.2% 범위에서 감소되었다. 두 번째 피크 질량손실속도($2^{nd}-TMLR_{peak}$) 시간은 DMDAP에 대해서 1.8%, DBDAP에 대해서 5.3% 감소하였고 DEDAP에 대하여 1.8% 증가하였다. 피크 일산화탄소 생성농도($CO_{peak}$)는 처리되지 않은 시편보다 1.5~2.0배 더 높았다. 피크 이산화탄소 생성 농도($CO_{2peak}$)는 처리되지 않은 시편과 비교하여 DMDAP에 대해 0.01배 감소되었고 DEDAP에 대해 1.15배, DBDAP에 대해 1.19배 증가하였다. 특히 산소농도는 사람에게 치명적인 15%보다 매우 높게 측정되었다. 전반적으로 가연성 기체의 연소 독성은 처리하지 않은 시편과 비교하여 화학 첨가제에 의해 부분적으로 증가하였다.

• 한국수소및신에너지학회논문집
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• 제17권1호
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• pp.62-68
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• 2006

High temperature electrolysis is a promising technology to produce massively hydrogen using renewable and nuclear energy. Solid oxide fuel cell materials are candidates as the components of steam electrolysers. However, the polarization characteristics of the typical electrode materials during the electrolysis have not been intensively investigated. In this study, NiO electrode was deposited on YSZ electrolyte by spin coat process and firing at $1300^{\circ}C$. Pt electrode was applied on the other side of the electrolyte to compare the polarization characteristics with those by NiO during electrolysis. The $H_2$ evolution rate was also monitored by measuring the electromotive force of Lambda probe and calculated by thermodynamic consideration. At low current density, Pt showed lower cathodic polarization and thus higher current efficiency than Ni, but the oxidation of Ni into NiO caused the increase of anodic resistance with increasing current density. High overpotential induced high power consumption to produce hydrogen by electrolysis.