• 대한화학회지
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• 제61권1호
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• pp.12-15
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• 2017

We presented a mapping the work function of the vanadium pentoxide ($V_2O_5$) nanonet structures by scanning Kelvin probe microscopy (SKPM). In this measurement, the $V_2O_5$ nanonet was self-assembled via dropping the solution of $V_2O_5$ nanowires (NWs) onto the $SiO_2$ substrate and drying the solvent, resulting in the networks of $V_2O_5$ NWs. We found that the SKPM signal as a surface potential of $V_2O_5$ nanonet is attributed to the contact potential difference (CPD) between the work functions of the metal tip and the $V_2O_5$ nanonet. We generated the histograms of the CPD signals obtained from the SKPM mapping of the $V_2O_5$ nanonet as well as the highly ordered pyrolytic graphite (HOPG) which is used as a reference for the calibration of the SKPM tip. By using the histogram peaks of the CPD signals, we successfully estimated the work function of ~5.1 eV for the $V_2O_5$ nanonet structures. This work provides a possibility of a nanometer-scale imaging of the work function of the various nanostructures and helps to understand the electrical characteristics of the future electronic devices.

• Carbon letters
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• 제21권
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• pp.81-85
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• 2017

The objective of this study is the removal of chromium from tannery wastewater by electrosorption on carbon prepared from lignocellulosic natural residue "peach stones' thermally treated. The followed steps for obtaining coal in chronological order were: cleaning, drying, crushing and finally its carbonization at $900^{\circ}C$. The characterization of the carbon material resulted in properties comparable to those of many coals industrially manufactured. The study of the dynamic adsorption of chromium on the obtained material resulted in a low removal rate (33.7%) without applied potential. The application of negative potentials of -0.7 V and -1.4 increases the adsorption of chromium up to 90% and 96% respectively. Whereas a positive potential of +1.4V allows desorption of the contaminant of 138%.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1998년도 춘계학술발표회 초록집
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• pp.3-3
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• 1998

The atmospheric corrosIOn properties of Zinc (Zn) under wet/dry transition of $H_20$ film were investigated in this study. The atmospheric corrosion of metal is usually occurred as a result of repetitious thickness transition (so called wet/dry transition) of liquid phase which is covering the metal surface. Corrosion potential and the polarization behaviour of Zn during liquid film thickness transition were measured by Kelvin probe method which IS using vibrating reference electrode without touching the liquid film. The oxidized states of Zn as a result of successive wet/dry transition were also investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the corrosion potential and the corrosIOn rate of Zn both are increasing during drying. However, the corrOSIon rate is decreasing again when the Zn surface is completely dried while the corrosion potential still remains high. This behaviour can be explained by the polarization behaviour change of Zn according to the $H_20$ film thickness change. The completely dried surface is consisted mostly with Zn and ZnO phases. After a number of cycles of wet/dry transition, however, the oxidized Zn phase of ${\varepsilon}-Zn(OH)_2$, which has rather voluminous and defected structure, were found.

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.500-506
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• 2017

To investigate the potential applications of bacterial heme, aminolevulinic acid synthase (HemA) was expressed in a Corynebacterium glutamicum HA strain that had been adaptively evolved against oxidative stress. The red pigment from the constructed strain was extracted and it exhibited the typical heme absorbance at 408 nm from the spectrum. To investigate the potential of this strain as an iron additive for swine, a prototype feed additive was manufactured in pilot scale by culturing the strain in a 5 ton fermenter followed by spray-drying the biomass with flour as an excipient (biomass: flour = 1:10 (w/w)). The 10% prototype additive along with regular feed was supplied to a pig, resulting in a 1.1 kg greater increase in weight gain with no diarrhea in 3 weeks as compared with that in a control pig that was fed an additive containing only flour. To verify if C. glutamicum-synthesized heme is a potential electron carrier, lactic acid bacteria were cultured under aerobic conditions with the extracted heme. The biomasses of the aerobically grown Lactococcus lactis, Lactobacillus rhamosus, and Lactobacillus casei were 97%, 15%, and 4% greater, respectively, than those under fermentative growth conditions. As a potential preservative, cultures of the four strains of lactic acid bacteria were stored at $4^{\circ}C$ with the extracted heme and living lactic acid bacterial cells were counted. There were more L. lactis and L. plantarum live cells when stored with heme, whereas L. rhamosus and L. casei showed no significant differences in live-cell numbers. The potential uses of the heme from C. glutamicum are further discussed.

• 한국작물학회지
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• 제49권6호
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• pp.491-495
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• 2004

기존의 내탈립성 참깨들은 우리나라 환경에서의 적응성이 떨어지며 수량성도 낮았으나, 계속적인 개량으로 인해 기존품종보다 내탈립성이 뛰어나면서도 수량성 등 제반 형질이 뒤지지 않는 새로운 내탈립성 참깨의 개발을 목전에 두고 있다. 그러나 앞으로도 계속적인 개량이 필요한 이들 내탈립성 참깨의 효율적인 육성 기술은 아직 부족한 실정이다. 따라서 본 시험에서는 이와 관련된 기술로 참깨 종자의 내탈립성을 나타내는 구체적인 기작 및 효율적인 탈립성 검정 방법 등을 밝히고자 수행하였던 결과를 요약하면 다음과 같다. 참깨 종자의 내탈립성의 원인을 검토한 결과 PA형의 내탈립성은 꼬투리(capsule)내 태좌의 종자 보유력이 크기 때문에 나타난 것으로 추정되었으며, ID형은 꼬투리의 중과피(mesocarp) 두께가 일반 참깨보다 두껍기 때문이었으며, SL형은 꼬투리에 seam이 존재하지 않기 때문이었다. 또한 내탈립성 참깨들은 일부의 개체에서 탈립성이 큰 변이가 나타났는데, 이는 이들 참깨들의 진화방향이 탈립성이 큰 방향임을 의미하는 것으로 판단되었다. 탈립성 측정을 위한 적합한 건조 조건은 상온에서는 참깨 수확 후 최소 20일, $40^{\circ}C$의 건조기 내에서는 10일 이상의 건조기간이 필요한 것으로 나타났다.

• 청정기술
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• 제15권3호
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• pp.154-164
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• 2009

2007년을 기준으로 울산에 위치한 사업장으로부터 발생된 유기성 폐수슬러지의 94%가 해양처분되었다. 유기성 슬러지의 해양처분은 2012년에는 완전 금지될 예정이다. 그러나 아직까지 울산에 위치한 사업장으로 부터의 유기성 슬러지는 소각 이외에 다른 대안이 없는 실정이며, 현재 울산석유화학산업단지의 사업장들은 슬러지의 육상처리 및 처분기술의 확보가 매우 중요한 과제이다. 본 연구에서는 울산의 석유화학사업장 슬러지와 하수처리 슬러지를 연료로 활용하기 위해 건조슬러지와 탄화슬러지의 재료적 측면에 대한 평가를 실시하였다. 연구결과 저위발열량 3,000 kcal/kg이상을 초과하는 테레프탈산, BTX, 프로필렌, 화학섬유 등을 생산하는 사업장으로부터의 건조슬러지와 탄화슬러지는 연료로서의 가능성이 높지만 건조할 경우 2,100 kcal/kg 이하, 탄화할 경우 1,100 kcal/kg 이하인 좀 더 무기성분이 많은 펄프, 제지, 메틸아민, 아마이드 등을 생산하는 사업장의 폐수슬러지는 연료로서의 가치가 적은 것으로 나타났다. 연구결과 대부분의 슬러지들이 에너지 측면에 있어서 탄화보다는 건조가 더 좋은 결과를 보여주었다.

• 콘크리트학회논문집
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• 제18권3호
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• pp.331-338
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• 2006

본 연구에서는 서로 다른 양생 조건하에서 W/C가 0.32~0.50인 콘크리트의 체적 변화를 실험을 통해 조사하였다. 콘크리트의 팽창뿐만 아니라 자기수축 및 건조수축을 측정하기 위해 4개의 서로 다른 양생 방법이 적용되었다. 밀봉을 통하여 수분 증발을 억제한 양생(조건 I)에서의 콘크리트는 자기수축만을 나타내었으며, W/C가 낮을수록 자기수축이 증가하였다. 처음 6일간 수중 양생한 후 $20{\pm}1^{\circ}C,\;60{\pm}3%$ RH의 조건에 노출시킨 기건 양생(조건 II)에서는 콘크리트가 팽창하였다가 수축하였다. 최대 팽창량은 $15{\sim}40{\pm}10^{-6}$ 정도였으며, W/C가 0.32인 콘크리트에서 가장 큰 전체 수축(자기수축+건조수축)량을 보였다. 처음부터 기건 양생(조건 III)한 콘크리트의 전체 수축은 양생 조건 II에서보다 증가하였다. 6일간의 밀봉 양생 후 기건 양생(조건 IV)한 경우에는 전체 수축이 양생 조건 III에 비해 다소 줄어들었다. 양생 조건 I, III, IV에서의 수축 결과로부터 순수한 건조수축량을 구할 수 있으며, 전체 수축량은 비슷함에도 불구하고 W/C가 증가함에 따라 건조수축이 증가하였다. 이는 W/C가 큰 콘크리트에서는 건조수축이 전체 수축을 지배함을 의미한다. 다시 말해, W/C가 낮은 콘크리트인 경우 전체 수축에서 자기수축이 차지하는 비율이 증가하기 때문에 잠재적인 균열 발생 측면에서 자기수축에 대한 검토가 반드시 요구된다. 결론적으로, 고강도 또는 고성능 콘크리트의 전체 수축은 적절한 초기 수중 양생을 통하여 효과적으로 줄일 수 있을 것으로 판단된다.

• 한국환경과학회지
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• 제22권2호
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• pp.187-193
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• 2013

Dry matter allocation characteristics of Calystegia soldanella, grown in pots, was analysed to assess its plasticity in response to water-stressed conditions. As water was withheld leaf water potential between the two watering treatments was similar during the first 6 days, followed by a rapid decrease in water-stressed plants. The minimum leaf water potential was -1.50 MPa on day 15 and the maximum leaf water potential was about -0.5 MPa on day 0 in water-stressed plants. In well-watered plants leaf water potential was maintained almost consistently throughout the experiment. There was no significant difference in plant dry weight between the two watering treatments for 9 days after the start of experiment and that was remarkably increased thereafter, compared with that remained without any increase in water-stressed plants. In dry mass partitioning, however, the water-stressed plants showed a great plasticity, showing that there were 1.81, 1.35 and 0.81 times increase in root, stem and leaf, respectively. Dry mass partitioning in well-watered plants varied from 2% to 5%. The difference of dry mass partitioning between the two watering treatments was reflected in leaf mass per unit area (LMA) and root/shoot (R/S) ratio. LMA in water-stressed plants was lower than that in well-watered plants, while R/S ratio in water-stressed plants was higher in well-watered plants. This means that the water-stressed plants reduced its leaf area and increased dry mass partitioning into root and stem during the progress of soil drying. These results indicate that Calystegia soldanella inhabiting in sand dune cope with water stress with high plasticity which can adjust its dry mass partitioning according to soil water conditions.

• 한국환경농학회지
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• 제36권1호
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• pp.29-35
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• 2017

BACKGROUND: This study was carried out to assess a biochemical methane potential of giant miscanthus (Miscanthus sacchariflorus) which was a promising candidate energy crop due to a high biomass productivity, in order to utilize as a feedstock for the biogas production. METHODSANDRESULTS: Giant miscanthus was sampled the elapsing drying time of 6 months after harvesting. TS (Total Solid) and VS (Volatile Solid) contents were 94.7 and 90.8%. And CP (Crude Protein), EE (Ether Extracts), and CF (Crude Fiber) contents of giant miscanthus were 1.4, 0.46, and 46.12%, respectively. In the organic composition of giant miscanthus, the NDF (Neutral Detergent Fiber) representing cellulose, lignin, and hemicellulose contents showed 86.88%, and the ADF (Acid Detergent Fiber) representing cellulose and lignin contents was 62.91%. Elemental composition of giant miscanthus showed 47.75%, 6.44%, 41.00%, and 0.28% for C, H, O, and N, respectively, and then, theoretical methane potential was obtained to $0.502Nm^3kg^{-1}-VS_{added}$. Biochemical methane potential was assessed as the range of $0.154{\sim}0.241Nm^3kg^{-1}-VS_{added}$ resulting the lower organic biodegradability of 30.7~48.0%. CONCLUSION: Therefore the development of pretreatment technology of the giant miscanthus was needed for the improvement of anaerobic digestability.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.41-41
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• 2018

There has been an impetus in the development of biocontrol agents (BCAs) with the removal of a number of chemical compounds in the market, especially in the European Union. This has been a major driver in the development of Integrated Pest Management systems (IPM) for both pest and disease control. For control of mycotoxigenic fungi, there is interest in both control of colonization and more importantly toxin contamination of staple food commodities. Thus the relative inoculum potential of biocontrol agent vs the toxigenic specie sis important. The major bottlenecks in the production and development of formulations of biocontrol agents are the resilience of the strains, inoculum quality and formulation with effective field efficacy. It was recently been shown for mycotoxigenic fungi such as Aspergillus flavus, under extreme climate change conditions, growth is not affected although there may be a stimulation of aflatoxin production. Thus, the development of resilient biocontrol strains which can may have conserved control efficacy but have the necessary resilience becomes critical form a food security point of view. Indeed, under predicted climate change scenarios the diversity of pests and fungal diseases are expected to have profound impacts on food security. Thus, when examining the identification of potential biocontrol strains, production and formulation it is critical that the resilience to CC environmental factors are included and quantified. The problems in relation to the physiological competence and the relative humidity range over which efficacy can occur, especially pre-harvest may be increase under climate change conditions. We have examined the efficacy of atoxigenic strains of A. flavus and Clanostachys rosea and other candidates for control of A. flavus and aflatoxin contamination of maize, and for Fusarium verticillioides and fumonisin toxin control. We have also examined the potential use of fluidized-bed drying, nanoparticles/nanospheres and encapsulation approaches to enhance the potential for the production of resilient biocontrol formulations. The objective being the delivery of biocontrol efficacy under extreme interacting climatic conditions. The potential impact of climate change factors on the efficacy of biocontrol of fungal diseases and mycotoxins are discussed.