• 정보저장시스템학회논문집
• /
• 제9권2호
• /
• pp.42-47
• /
• 2013

In this study, we have experimentally analyzed how the surface properties of transparent electrode layer influence the photovoltaic performance of bulk heterojunction organic solar cell by the contact angle measurement and X-ray photoelectron spectroscopy(XPS) observation. As a result, the power conversion efficiency of test devices improved from 0.64% to 1.83% and 2.15% by UV-ozone exposure and $O_2$ plasma treatment, respectively. Thus, we conclude that the surface activation process is very important for better performance and stability in addition to the cleaning process of carbonate residue on the surface.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
• /
• pp.439-444
• /
• 1997

In order to investigate organic association of fallout cesium, strontium and plutonium in the soil, soil samples influenced by fallout from nuclear weapon testings were treated with alkali (0.1 M-sodium hydroxide solution) to extract organic acids. After extraction, the resultant three fractions (sedimentary residue, humic and fulvic acid fractions) were subjected to the r-ray spectrometric analysis for $^{137}$ Cs, and radiochemical analysis for gosr and $^{239,240}$Pu. Alkali extraction experiments showed that a lot of $^{ 239,240}$Pu was extracted to organic acids from the soil samples, whereas most of $^{137}$ Cs and $^{90}$ Sr remained in residual fraction. Less than 10% of the total $^{137}$ Cs and $^{90}$ Sr was found in the organic fraction. The concentrations of $^{137}$ Cs and $^{90}$ Sr associated with humic fractions were higher than those with the corresponding fulvic fractions. It was found that more than 40% of the total $^{239,240}$Pu was associated with the organic fraction of soils. In contrast with $^{137}$ Cs and $^{90}$ Sr, $^{239,240}$Pu associated with vulvic fractions was much higher than in humic fractions.

• Journal of Microbiology and Biotechnology
• /
• 제13권2호
• /
• pp.191-195
• /
• 2003

The in vitro glycosylation of pentapeptide (Arg-Lys-Asp-Val-Tyr; RKDVY) and RNase A was carried out using PNGase F (peptide-N-glycosidase F), and the results were analyzed using MALDI-TOF-MS. Aminated N,N-diretyl chitobiose was used as the sugar in the glycosylation reaction, and the amination yield of N,N'-diacetyl chitobiose was about $60\%$. To reduce the water activity and shift the reaction equilibrium to a reverse reaction, 1,4-dioxane or ethylene glycol was used as the organic solvent in the enzymatic glycosylation. A certain extent of nonenzymatic glycosylaton, known as the Maillard reaction, was also observed, which occurs on an arginine or lysine residue when the length of tie sugar residue is one or two. However, the extent of glycosylation was much higher in the enzymatic reaction, indicating that PNGase F can be effectively used to produce glycopeptides and glycoproteins in vitro.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 추계학술대회 논문집
• /
• pp.511-511
• /
• 2009

Lignocellulosic biomass is the most abundant organic material on earth and also promising raw material for bioenergy production. Agricultural residues in the process of bio-oil extraction, is an abundant and low-cost lignocellulosic material. The technology for conversion of lignocellulosic biomass resources to fuels and chemicals, such as ethanol, has been under development for decades. One of the well-studied technologies that are currently being commercialized is to use a dilute acid-catalyzed pretreatment followed by enzymatic hydrolysis and fermentation to produce ethanol. In this work, the dilute-acid hydrolysis of agricultural residues was optimized through the utilization of statistical experimental design. Evaluation criteria for optimization of the pretreatment conditions were based on high xylose recovery and low inhibitor contents in the hydrolyzates. The purpose of this study was to gain a more accurate understanding of the quantities of acid required for effective hydrolysis and the reactivity trade-offs with reaction time and temperature that will enable overall process optimization.

• 공업화학
• /
• 제32권5호
• /
• pp.487-496
• /
• 2021

Microalgae is one of the promising biodiesel feedstock with high growth rates compared to those of terrestrial oil crops. Despite its numerous advantages, biodiesel production from microalgae needs to reduce energy demand and material costs further to go to commercialization. During solvent extraction of microalgal lipids, lipid-extracted algae (LEA) cell residue is generated as an organic solid waste, about 80-85% of original algal biomass, and requires an appropriate recycling or economic disposal. The resulting LEA still contains significant amount of carbohydrates, proteins, N, P, and other micronutrients. This review will focus on recent advancement in the utilization of LEA as: (i) utilization as nutrients or carbon sources for microalgae and other organisms, (ii) anaerobic digestion to produce biogas or co-fermentation to produce CH₄ and H₂, and (iii) conversion to other forms of biofuel through thermochemical degradation processes. Possible mutual benefits in the integration of microalgae cultivation-biodiesel production-resulting LEA with anaerobic digestion and thermochemical conversion are also discussed.

• Asian-Australasian Journal of Animal Sciences
• /
• 제17권2호
• /
• pp.278-282
• /
• 2004

Compost is used mainly as an organic fertilizer, but it is also used as bedding material for cattle. Dairy cattle have been identified as a main reservoir of pathogenic Escherichia coli O157:H7. Further, E. coli is regarded as an environmental pathogen that causes bovine clinical mastitis. Hence, its growth in compost spread or compost bedding should be avoided. Physical and chemical conditions, available nutrients and microflora in compost change greatly during the composting process. Since pathogen growth in compost seems to be related to these changes, we assessed the possibility of E. coli growth in compost samples collected at 0, 7, 13, 22, 41, 190 and 360 d. Cattle waste composts with and without added tofu residue were collected from static piles and immediately air-dried. Compost samples were inoculated with a pure culture of E. coli, the moisture content was adjusted to 50%, and the samples were incubated for 5 d at $30^{\circ}C$. The numbers of E. coli in compost before and after incubation were determined by direct plating on Chromocult coliform agar. Almost all compost samples supported E. coli growth. Samples collected during or immediately after the thermophilic phase (day 7) showed the highest growth. Growth in samples more than 13 d old were not significantly different from those of aged compost samples. The addition of tofu residue gave a higher growth than its absence in younger samples collected prior to 13 d. To minimize the risk of environmental mastitis, the use of compost in the initial stage of the process is better avoided.

• Journal of Microbiology and Biotechnology
• /
• 제32권5호
• /
• pp.564-574
• /
• 2022

Microbial diversity in the soil is responsive to changes in soil composition. However, the impact of soil amendments on the diversity and structure of rare and abundant sub-communities in agricultural systems is poorly understood. We investigated the effects of different Chinese herb residue (CHR) soil amendments and cropping systems on bacterial rare and abundant sub-communities. Our results showed that the bacterial diversity and structure of these sub-communities in soil had a specific distribution under the application of different soil amendments. The CHR soil amendments with high nitrogen and organic matter additives significantly increased the relative abundance and stability of rare taxa, which increased the structural and functional redundancy of soil bacterial communities. Rare and abundant sub-communities also showed different preferences in terms of bacterial community composition, as the former was enriched with Bacteroidetes while the latter had more Alphaproteobacteria and Betaproteobacteria. All applications of soil amendments significantly improved soil quality of newly created farmlands in whole maize cropping system. Rare sub-communitiy genera Niastella and Ohtaekwangia were enriched during the maize cropping process, and Nitrososphaera was enriched under the application of simple amendment group soil. Thus, Chinese medicine residue soil amendments with appropriate additives could affect soil rare and abundant sub-communities and enhance physicochemical properties. These findings suggest that applying soil composite amendments based on CHR in the field could improve soil microbial diversity, microbial redundancy, and soil fertility for sustainable agriculture on the Loess Plateau.

• 농약과학회지
• /
• 제16권4호
• /
• pp.308-314
• /
• 2012

국내 유통 중인 친환경농산물 중 과채류와 과실류의 잔류농약 모니터링을 통해 친환경인증 농산물의 잔류농약 실태조사 및 안전성을 평가하기 위하여 서울을 포함한 전국 8개 도시 9개 지점의 대형마트와 친환경농산물 전문판매점에서 25종의 과채류와 과실류를 555점 채취한 후 acetamiprid를 포함한 245종 농약을 대상으로 GC-ECD/NPD와 HPLC-DAD/FLD를 이용한 다성분동시분석법으로 잔류농약을 분석하였으며, 분석결과 농약으로 추정되는 peak는 GC-MSD를 이용하여 재확인하였다. 잔류농약 분석결과 555점의 시료 중 사과를 포함한 4점의 시료에서 bifenthrin, EPN 및 chlorpyrifos가 검출되었으며, 검출율은 0.72%이었다. 농약이 검출된 4점의 시료 중 잔류량은 모두 잔류허용기준(maximum residue limit, MRL) 이내였으나 EPN이 검출된 배는 잔류량이 허용수준인 MRL의 1/20을 초과하였다. 일일최대섭취허용량(maximum permissible intake, MPI) 대비 일일섭취추정량(estimated daily intake, EDI)은 0.76% 미만이었다.

• 유기물자원화
• /
• 제26권2호
• /
• pp.75-84
• /
• 2018

본 연구에서는 하수슬러지의 연료화를 위하여 반탄화 생성물을 분석하였다. 혼합시료는 하수슬러지 함량을 50%로 고정하고, 왕겨와 커피박의 함량을 50%로 조절하여 제조하였다. 반탄화 실험에서 반응 시간(30min, 60min)과 온도($200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$)를 SF(Severity Factor)를 이용하여 단일변수로 나타내었다. 연구 결과 반탄화 조건인 SF가 증가할수록 발열량과 연료비가 증가하였으며, 연소성지수는 감소하는 것을 확인하였다. 혼합시료의 발열량은 커피박(CR)과 반탄화 조건(SF) 모두의 영향을 받는 것으로 나타났으며, 연료비 범위는 SF가 6.19보다 낮은 경우 갈탄의 연료비 범위(0.5~1.0)와 유사하나 SF가 7.36보다 큰 경우 저도역청탄의 연료비 범위(1.0~1.8)와 유사한 것을 확인하였다. 연소성지수는 커피박보다는 왕겨가 더 함유될수록 낮은 조건의 SF에서 안정 범위(3,000~5,500kcal/kg)의 값을 나타내는 것으로 확인되었다.

• 환경영향평가
• /
• 제24권1호
• /
• pp.1-15
• /
• 2015

농업생태계에 대한 기후변화의 영향을 경감시키기 위해 토양탄소격리를 증대시키기 위한 영농관리기법 개발이 요구되고 있다. 본 연구에서는 토양유기탄소에 대한 비종(화학비료와 퇴비), 작부체계, 작물잔사관리의 영향을 조사하였다. 화학비료와 퇴비 시험포를 조성하여 자연 강우 조건에서 옥수수-보리를 2년동안 재배하고 토양내 SOC의 분석을 위해 토양샘플링을 실시하였다. 영농관리에 따른 SOC의 장기변화 패턴을 추정하기 위해 DNDC모형을 1981년부터 2010년까지 기상자료와 실험자료 기반 매개변수로 모의하였다. DNDC 모의에 의하면 화학비료 처리구에서는 작물잔사 환원이 없으면 SOC가 감소하는 것으로 나타났다. 반면 퇴비 처리구에서는 같은 조건에서 SOC가 증가하였고, SOC의 증가는 퇴비의 시비율에 비례하였다. 또한 SOC는 투입된 퇴비량의 증가로 인해 옥수수 단작보다 옥수수-보리 작부체계에서 더 증가하였다. 비종에 관계없이 작물잔사의 토양환원은 SOC 증가를 가져왔지만, 퇴비시용의 경우 잔사환원 효과는 작은 것으로 나타났다.