• 한국식품저장유통학회지
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• 제3권1호
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• pp.55-60
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• 1996

To obtain the basic data on precooling effects for establishment the suitable postharvest handling technique or method of keeping high quality of vegetalble corn, the sweet, supersweet and waxy corn, (Danok #2, Cocktail #86 and Chalok #1), being mainly consumed as vegetables in Korea, were precooled with ice or vacuum cooling method immediately after harvest. The vacuum cooling was the most effective for the field heat removal of vegetable corn. It took only 30 min. at 4 to 5 torr of cold chamber pressure of vacuum precooler to lower the corn temperature from 30 to 2$^{\circ}C$. The ice cooling was also thought to be a useful precooling method with relatively short cooling time of 6 hrs. The vegetable corn treated with vacuum or ice cooling showed low and stable respiration rates of 25.5 to 43.5 CO2 mg/kg/hr. when stored at 0∼2$^{\circ}C$ while the samples stored at room temperature (20∼25$^{\circ}C$) without precooling were as high as 64.1 to 245 CO, mg/kg/hr.

• Journal of Microbiology and Biotechnology
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• 제28권10호
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• pp.1706-1715
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• 2018

Several non-methylotrophic bacteria have been reported to improve the growth and activity of methanotrophs; however, their interactions remain to be elucidated. We investigated the interaction between Methylocystis sp. M6 and Microbacterium sp. NM2. A batch co-culture experiment showed that NM2 markedly increased the biomass and methane removal of M6. qPCR analysis revealed that NM2 enhanced both the growth and methane-monooxygenase gene expression of M6. A fed-batch experiment showed that co-culture was more efficient in removing methane than M6 alone (28.4 vs. $18.8{\mu}mol{\cdot}l^{-1}{\cdot}d^{-1}$), although the biomass levels were similar. A starvation experiment for 21 days showed that M6 population remained stable while NM2 population decreased by 66% in co-culture, but the results were opposite in pure cultures, indicating that M6 may cross-feed growth substrates from NM2. These results indicate that M6 apparently had no negative effect on NM2 when M6 actively proliferated with methane. Interestingly, a batch experiment involving a dialysis membrane indicates that physical proximity between NM2 and M6 is required for such biomass and methane removal enhancement. Collectively, the observed interaction is beneficial to the methanotroph but adversely affects the non-methylotroph; moreover, it requires physical proximity, suggesting a tight association between methanotrophs and non-methylotrophs in natural environments.

• 청정기술
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• 제22권2호
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• pp.106-113
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• 2016

본 연구에서는 UV 광을 이용하여 CO, C₂H₅OH 및 H₂S에 해당하는 오염물질을 제어하기 위한 광촉매 연구를 수행하였다. 제조된 촉매들이 동일한 체적 및 표면적의 경우에는 촉매 구조 내부까지 UV 광이 조사될 수 있는 구조에서 우수한 반응활성을 보였다. 하지만 이러한 광촉매 TiO₂의 CO에 대한 반응활성은 매우 저조하였으며, 이는 귀금속 계열의 Pt를 첨가하여 환원공정을 수행함으로써 해결할 수 있다. 특히 이러한 Pt/TiO₂ 광촉매는 환원공정을 통하여 표면 Pt⁰의 종의 생성 및 증가시킬 수 있으며, 이를 통해 CO의 반응활성이 우수해 짐을 확인하였다.

• 한국식품과학회지
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• 제26권2호
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• pp.127-132
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• 1994

알긴산 제거시 전반적으로 고형분 및 단백질 수율이 감소하였고 UF처리가 $CaCl_2$ 첨가시 보다 더 뚜렸한 감소를 보였으며 점도는 알긴산 제거전 $84{\sim}94\;cps$이었던 것이 10cps로 감소하였고 탁도 또한 현저히 감소하였다. 아미노태 질소의 회수량은 $CaCl_2$ 첨가보다 UF처리한 것이 적었고 특히 NaCl을 첨가시 가장 적게 나타났으며 mannitol은 추출방법에 따른 변화가 없었다. 유기산은 oxalic acid의 함량이 높았으며 효소처리 후 NaCl 1.5%를 첨가하여 추출한 시료가 전반적으로 함량이 높게 나타났으며 핵산 조성은 분말과 2시간 열수추출의 경우 4가지 핵산이 비교적 균등한 분포를 보였으나 알긴산 제거시 일부 핵산이 함께 제거되어 핵산조성비율에 영향을 주었다. 특히 $CaCl_2$에 의한 침전제거는 IMP가 전부 그리고 UMP가 많이 손실되었으며 UF처리가 $CaCl_2$ 방법보다 핵산손실이 훨씬 적었다. 추출액의 아미노산 조성은 전체함량 중 aspartic acid와 glutamic acid가 80% 이상을 차지하고 있고 그 밖의 아미노산 함량은 대단히 적게 나타났으며 tryptophan, proline등 일부 아미노산은 검출되지 않았다.

• 청정기술
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• 제12권2호
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• pp.67-77
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• 2006

본 연구에서 소규모 하수고도처리를 위한 이중슬러지(Dual sludge) $KNR^{(R)}$ (Kwon's nutrient removal) 시스템이 개발되었다. $KNR^{(R)}$ 시스템은 부유성장식 탈질미생물과 부착성장식 질산화미생물을 분리시킨 이중슬러지 공정으로 최초침전조, 혐기조, 무산소조, 농축조의 복합기능을 수행하는 UMBR (Upflow multi-layer bioreactor)과 펠렛형 담체가 충진된 호기성 담체조로 구성되어 있다. 소규모 하수처리시 본 개발공정의 안정성과 처리성능을 평가하기 위해 처리용량 $50m^3/d$ 규모의 파일럿 플랜트를 고도처리 공정으로 개선공사 중인 처리용량 $50m^3/d$ 규모의 실제 소규모 마을하수처리장에 적용하였다. UMBR과 담체조의 체류시간은 각각 4.7 h와 7.2h이었으며, 반응조 수온은 $18.1{\sim}28.1^{\circ}C$이었다. 유입 하수량과 유입수의 BOD/N의 변동폭이 컸음에도 불구하고 파일럿 플랜트는 안정된 처리성능을 보였다. 전체 실험기간 중 처리수의 $COD_{cr}$, $COD_{Mn}$, $BOD_5$, TN, TP의 평균 농도는 11.0 mg/L, 8.8 mg/L, 4.2 mg/L, 3.5 mg/L, 9.8 mg/L, 0.87/0.17 mg/L (poly aluminium chloride(PAC) 투입/미투입)이었으며, 제거율을 각각 95.3%, 87.6%, 96.3%, 96.5%, 68.2%, 55.4/90.3% 이었다. 잉여슬러지 발생량은 $A_2O$와 Bardenpho 등과 같은 단일슬러지를 이용하는 고도처리공정과 비교시 약 1.9~3.8배 낮은 $0.026kg-DS/m^3$ and 0.220 kg-DS/kg-BOD로 나타났다.

• 한국대기환경학회지
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• 제24권6호
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• pp.641-648
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• 2008

A plate-type dielectric barrier discharge (DBD) reactor was designed and tested for removal of gaseous toluene. The DBD reactor consisted of 9 parallel plate electrodes, four of which were grounded. An AC voltage of rectangular waveform ($5{\sim}8.5kV$, $60{\sim}1,000Hz$), was applied to the other five electrodes. The gaseous toluene passed through the DBD reactor and its concentration was measured by a real-time gas analyzer. The carbon monoxide (CO) and carbon dioxide ($CO_2$) which were produced by decomposition of toluene in the DBD reactor, were sampled and analyzed by a micro gas chromatography. The maximum toluene removal efficiency was 51.4%.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.627-636
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• 2022

In nuclear power plants and other nuclear facilities the removal of cobalt from radioactive liquid waste is needed to reduce the radioactivity concentration in effluents. In liquid wastes containing strong organic complexing agents such as EDTA cobalt removal can be problematic due to the high stability of the Co-EDTA complex. In this study, the removal of cobalt from NaNO₃ solutions using antimony oxide (Sb₂O₃) synthesized from potassium hexahydroxoantimonate was investigated in the absence and presence of EDTA. The uptake studies on the ion exchange material were conducted both in the dark (absence of UV-light) and under UV-C irradiation. Ca²⁺ or Ni²⁺ were included in the experiments as competing cations to test the selectivity of the ion exchanger. Results show that UV-C irradiation noticeably enhances the cobalt sorption efficiency on the antimony oxide. It was shown that nickel decreased the sorption of cobalt to a higher extent than calcium. Finally, the sorption data collected for Co²⁺ on antimony oxide was modeled using six different isotherm models. The Sips model was found to be the most suitable model to describe the sorption process. The Dubinin-Radushkevich model was further used to calculate the adsorption energy, which was found to be 6.2 kJ mol^-1.

• 대한환경공학회지
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• 제32권1호
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• pp.17-22
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• 2010

본 연구의 목적은 대형 석탄 화력 발전소에 DSI (Dry Sorbent Injection)공정을 실제 적용 할 경우에 실현 가능성에 대한 연구로서 N 발전(주)의 S 화력발전본부에서 운용중인 500MW급 석탄화력 발전시설의 보일러 후단에서 전기 집진기 전 단까지를 모델로 삼아 Lab-scale 실험장치를 제작하여 탈황효율을 높이기 위한 실험을 수행하였다. 이를 위하여 Lobedplate와 Step-plate라는 혼합촉진장치를 고안하고 각각 형상을 달리하여 궁극적으로 탈황효율을 높이기 위한 혼합촉진장치의 최적 형상도출을 위한 실험을 수행하였으며 부수적으로 탈황제의 분사구의 개수에 따른 탈황효율 또한 분석하였다. 그 결과 혼합촉진장치가 설치된 경우가 더 높은 탈황 효율을 나타내었고 형상에서는 계단형상일 경우 가장 높은 탈황효율을 보였다. 또한, 탈황제의 분사구의 개수에 따른 탈황효율은 혼합 촉진 장치가 설치되지 않은 경우, 분사구의 개수가 증가할수록 높은 탈황 효율을 보였으나 혼합촉진장치가 설치된 경우는 분사구의 개수가 4개일 경우가 이론적 결과와 같이 가장 높은 탈황효율을 나타내었다.

• Transactions on Electrical and Electronic Materials
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• 제2권3호
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• pp.24-27
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• 2001

The end point of oxide chemical mechanical polishing (CMP) have determined by polishing time calculated from removal rate and target thickness of oxide. This study is about control of oxide removal amounts on the shallow trench isolation (STI) patterned wafers using removal rate and thickness of blanket (non-patterned) wafers. At first, it was investigated the removal properties of PETEOS blanket wafers, and then it was compared with the removal properties and the planarization (step height) as a function of polishing time of the specific STI patterned wafers. We found that there is a relationship between the oxide removal amounts of blanket and patterned wafers. We analyzed this relationship, and the post CMP thickness of patterned wafers could be controlled by removal rate and removal target thickness of blanket wafers. As the result of correlation analysis, we confirmed that there was the strong correlation between patterned and blanket wafer (correlation factor: 0.7109). So, we could confirm the repeatability as applying for STI CMP process from the obtained linear formula. As the result of repeatability test, the differences of calculated polishing time and actual polishing time was about 3.48 seconds. If this time is converted into the thickness, then it is from 104 $\AA$ to 167 $\AA$. It is possible to be ignored because process margin is about 1800 $\AA$.

• 신재생에너지
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• 제16권1호
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• pp.68-76
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• 2020

Operational testing of the THIOPAQ^® facility that removes H₂S from landfill gas was performed for 746 days. The average H₂S removal efficiency was 99.4%, and the input quantities of air, NaOH, and nutrients per sulfur load were 13.1 ㎥/ton, 1.5 ㎥/ton, and 28.7 L/ton, respectively. The purity of the bio-sulfur produced from the facility was 94.8%, with 3.3% impurities, except for moisture. X-ray photoelectron spectroscopy showed that the compositional contents of amino acids and free amino acids of the bio-sulfur surface were 5,308 and 728 mg/kg, respectively. The mean particle size was 3.41 ㎛, which was much smaller than that of chemical sulfur. Based on these results, a high H₂S removal rate of more than 97% is feasible, and high value-added bio-sulfur, which is used as a fungicide because of its hydrophilic characteristics and small size, can be obtained at this facility.