• Nuclear Engineering and Technology
• /
• 제43권6호
• /
• pp.547-556
• /
• 2011

Two computational methods for determining equilibrium states for the Mark-IV electrorefiner (ER) have been assessed to improve the current computational electrorefiner model developed at University of Idaho. Both methods were validated against measured data to better understand their effects on the calculation of the equilibrium compositions in the ER. In addition, a sensitivity study was performed on the effect of specific unknown activity coefficients-including sodium in molten cadmium, zirconium in molten cadmium, and sodium chloride in molten LiCl-KCl. Both computational methods produced identical results, which stayed within the 95% confidence interval of the experimental data. Furthermore, sensitivity to unavailable activity coefficients was found to be low (a change in concentration of less than 3 ppm).

• 대한화학회지
• /
• 제65권2호
• /
• pp.145-150
• /
• 2021

The present study describes a hands-on experiment to help students understand the concept of phase change or phase transition and its application in a phase change material (PCM). PCMs are substances that have the capability of storing and releasing large amounts of thermal energy. They act as energy storage materials that provide an effective way to save energy by reducing the electricity required for heating and cooling. Lauric acid (LA) was selected as an example of the PCM. Students investigated the temperature change of LA and the temperature (of air) inside the test tube. The differences in the temperatures of the systems helped students understand how PCMs work. A one-group pretest and posttest design was implemented with 34 grade-11 students in science and mathematics. Students' understanding was assessed using a multiple-choice test and a questionnaire. The findings revealed that the designed activity helped students understand the concept of phase change and its application to materials for thermal energy storage.

• 농업과학연구
• /
• 제39권2호
• /
• pp.189-194
• /
• 2012

It is well-known fact that woodworking activity could contribute in enhancing creativity, scientific problem-solving ability, spatial perception ability and prosocial behavior of children. However, there is little chance that children experience woodworking at home or in kindergarten. This study was conducted to know how much children and adults have done woodworking in there daily life and how they perceived children's woodworking activity. Woodworking activities for children (N=207, 5 and 6 year old kids) with adults (N=271, only fathers) were carried out in 10 kindergartens of Cheongju. Actually, the survey result shows that very few children and adults experienced woodworking in their daily life. 62.8% of children and 34.3% of adults surveyed responded that they had never done woodworking. However, the greater part of children and adults evaluated the woodworking activity positively. Over 95% of children surveyed responded that their woodworking activity was fun and they want to play woodworking again. Over 73% of adults surveyed responded that children's woodworking activity was safe, and over 99% of adults surveyed responded that they can recommend children's woodworking activity to others. In conclusion, the development of safe tools and programs for children's woodworking activity helps its spread and activation.

• The Plant Pathology Journal
• /
• 제38권5호
• /
• pp.461-471
• /
• 2022

Erwinia amylovora is a causative pathogen of fire blight disease, affecting apple, pear, and other rosaceous plants. Currently, management of fire blight relies on cultural and chemical practices, whereas it has been known that few biological resources exhibit disease control efficacy against the fire blight. In the current study, we found that an SFC20201208-M01 fungal isolate exhibits antibacterial activity against E. amylovora TS3128, and the isolate was identified as a Penicillium brasilianum based on the 𝛽-tubulin (BenA) gene sequence. To identify active compounds from the P. brasilianum culture, the culture filtrate was partitioned with ethyl acetate and n-butanol sequentially. From the ethyl acetate layer, we identified two new compounds (compounds 3-4) and two known compounds (compounds 1-2) based on spectroscopic analyses and comparison with literature data. Of these active compounds, penicillic acid (1) exhibited promising antibacterial activity against E. amylovora TS3128 with a minimal inhibitory concentration value of 25 ㎍/ml. When culture filtrate and penicillic acid (125 ㎍/ml) were applied onto Chinese pearleaf crab apple seedlings prior to inoculation of E. amylovora TS3128, the development of fire blight disease was effectively suppressed in the treated plants. Our results provide new insight into the biocontrol potential of P. brasilianum SFC20201208-M01 with an active ingredient to control fire blight.

• Bulletin of the Korean Chemical Society
• /
• 제35권7호
• /
• pp.1973-1978
• /
• 2014

Here, we present a facile method to synthesize Pt nanoparticles (NPs) and graphene composite materials (Pt/G) via vacuum filtration. Anodic aluminum oxide (AAO) templates were used to separate Pt/G composite and liquid phase. This method can be used to easily tune the mass ratio of Pt NPs and graphene. Pt NPs, graphene, and carbon nanotubes (CNTs) as building blocks were characterized by a variety of techniques such as scanning electron microscopy, UV-Vis spectroscopy, and Raman spectroscopy. We compared the electrocatalytic activities of Pt/G with Pt NP and CNT films (Pt/CNT) by cyclic voltammetry (CV), CO oxidation, and methanol oxidation. Pt/G was much more stable than pure Pt films. Also, Pt/G had better electrochemical activity, CO tolerance and methanol oxidation than Pt/CNT loaded with the same amount of Pt NPs due to the better dispersion of Pt NPs on graphene flakes without aggregation. We further synthesized Au@Pt disk/G and Pt nanorods/G to determine if our synthetic method can be applied to other NP shapes such as nanodisks and nanorods, for further electrocatalysis studies.

• Bulletin of the Korean Chemical Society
• /
• 제27권9호
• /
• pp.1423-1428
• /
• 2006

In this study, we have prepared pitch binded AC (activated carbon)/$AC/TiO_2$ composites photocatalysts through carbon tetrachloride solvent method. The developed samples were characterized with surface properties, structural crystallinity between AC and $AC/TiO_2$, elemental identification and photocatalytic activity. The results of the textural surface properties demonstrate that there are slight increases in the BET surface area and adsorbed volume from adsorption isotherm of composite samples with increasing of the amount of AC. The SEM results present to the characterization of porous texture on the pitch/AC/$AC/TiO_2$ composites and homogenous compositions in the particle for all the materials used. From XRD data, a weak and broad carbon peak of graphene remained rutile peaks kept with anatase structure were observed in the X-ray diffraction patterns for the pitch/AC/$AC/TiO_2$ composites. The EDX spectra show the presence of C, O and S with strong Ti peaks. Most of these samples are richer in carbon and major Ti metal than any other elements. Finally, the excellent photocatalytic activity of the pitch/AC/$AC/TiO_2$ composites between relative concentration ($c/c_o$) of MB and UV irradiation time could be attributed to the both effects between photocatalysis of the supported $AC/TiO_2$ and adsorptivity of the two kinds of carbons.

• 유기물자원화
• /
• 제17권4호
• /
• pp.59-65
• /
• 2009

돼지의 장 및 분변에서 분리한 14종의 유산균으로부터 항세균 활성물질을 분석하였다. 각 균주의 세포배양액을 대상으로 여러 종류의 단백질 분해효소와 열, 알칼리 처리 등을 수행한 후 활성도를 조사한 결과, 효소 및 열처리 시료에서는 활성도가 유지되었으나, 1M의 NaOH로 중화 처리한 시료에서는 활성도가 사라짐에 따라, 항세균 활성물질이 단백질성이라기보다 유기산일 가능성이 큰 것으로 나타났다. Sep-pak $C_{18}$ Cartridges을 이용한 음이온 추출실험과 Bio-LC system을 이용한 high performance anion exchange chromatography를 실시하여 물질을 정제한 결과, 주요 활성물질로 옥살산, 구연산, 젖산 및 초산 등, 4종류의 유기산이 검출되었다. 이중 젖산은 각 균주에 따라 전체 유기산의 54~77%를 차지하는 것으로 나타나 유기산 중에서도 일차적인 항세균 활성물질일 것으로 추정된다.

• 한국동물학회지
• /
• 제12권3호
• /
• pp.77-84
• /
• 1969

著者는 白色레그혼의 種卵을 孵化시켜 얻은 鷄胎中 賢과 後賢에 있어서의 alk. p., PAS-陽性物質 및 燐脂質의 消長과 局在位置의 變異를 組織化學的 方法으로 追究하여 다음과 같은 結果를 얻었다. 1. 分泌尿細管의 器官形成에 앞서 未分化 間葉組織內에 强한 alk. p. 活性이 出現하였으며 同活性은 分泌尿細管의 分化와 함께 消失하였다. 2. 中賢 및 後賢 分泌尿細管의 分化와 함께 alk. p. 및 PAS-陽性物質은 分泌尿細管의 刷子綠에 强陽性反應을 보였다. 3. 中賢 및 後賢 分泌尿細管의 細胞質과 刷子綠은 强한 燐脂質 陽性反應을 띠었다. 4. 造賢組織의 分化中 未分化 間葉組織에 alk. p. 活性이 出現하였다가 組織의 分化와 함께 消失된 事實에서 보아 alk. p. 는 組織分化에 關與하는 것으로 생각된다. 5. 中賢 및 後賢 分泌尿細管의 刷子　 에 있어서 alk. p. 와 PAS-陽性物質 및 燐脂質의 變異와 分布狀態가 一致한 것으로 보아 alk. p. 는 炭水化物의 再吸收 및 燐脂質代謝에 關與하는 것으로 思料된다.

• Elastomers and Composites
• /
• 제50권3호
• /
• pp.223-230
• /
• 2015

Bacterial infection is one of the most common and universal cause of disease spreading associated with medical and surgical environment. Antimicrobial function of plasticized polyvinyl chloride (PVC) will be useful for making hygienic environments. Here, we synthesized the PVC composite by the addition of inorganic bacteriocide containing silver, zinc and zeolite. And we investigated the growth inhibition rate for Staphylococcus aureus and Klebsiella pneumoniae which were analyzed in the presence of PVC composite with different doses of inorganic bacteriocide (1~15 wt%). Bacterial proliferation was significantly inhibited by 3 wt% of inorganic bacteriocide containing PVC composite. And we found the inhibition of bacterial biofilm formation by 5 wt% of inorganic bacteriocide containing PVC composite by the observation of scanning electron microscopy (SEM). Our data suggested that the antimicrobial effect of inorganic bacteriocide was caused by disturbing the bacterial biofilm formation.

• Bulletin of the Korean Chemical Society
• /
• 제33권10호
• /
• pp.3407-3412
• /
• 2012

The Ti incorporation at Fe-site in the double perovskite lattice of $Sr_2FeNbO_6$ (SFNO) system is studied. The Ti concentration optimization yielded an efficient photocatalyst. At an optimum composition of Ti as x = 0.07 in $Sr_2Fe_{1-x}Ti_xNbO_6$, the photocatalyst exhibited 2 times the quantum yield for photolysis of $H_2O$ in presence of $CH_3OH$, than its undoped counterpart under visible light (${\lambda}{\geq}420nm$). Heavily Ti-doped $Sr_2Fe_{1-x}Ti_xNbO_6$ lattice exhibited poor photochemical properties due to the existence of constituent impurity phases as observed in the structural characterization, as well as deteriorated optical absorption. The higher electron-density acquired by n-type doping seem to be responsible for the more efficient charge separation in $Sr_2Fe_{1-x}Ti_xNbO_6$ (0.05 < x < 0.4) and thus consequently displays higher photocatalytic activity. The Ti incorporated structure also found to yield stable photocatalyst.