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Search Results: 1 - 10 of 11752 matches for " Jung Park "
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Detecting Photoacoustic Signals of Sulfur Hexafluoride at Varying Microphone Positions  [PDF]
Wittmann S. Murphy, Han Jung Park
Open Journal of Physical Chemistry (OJPC) , 2016, DOI: 10.4236/ojpc.2016.63005
Abstract: Photoacoustic spectroscopy was used to test the photoacoustic properties of sulfur hexafluoride, an optically thick and potent greenhouse gas. While exploring the photoacoustic effect of sulfur hexafluoride, the effects of the position of the microphone within a gas cell were determined. Using a 35 cm gas cell, microphones were positioned at 17.5 cm, the middle of the gas cell, 12.5 cm, 7.5 cm, and 2.5 cm from the window of the cell. From the photoacoustic signal produced for each resonance frequency at each microphone position, the effects of acoustic pressure produced at each position on the signal recorded were observed. This is the first study done by experimentation with the photoacoustic effect to show that standing waves have different amplitudes at different microphone positions.
Effects of Band Therapy Using Music on Grasping Power, Depression, and Personal Relationships in Nursing-Home-Dwelling Elderly Individuals  [PDF]
Eun Kyung Chang, Heeok Park, Miran Jung, Hae Kyeong Lee, Jieun Park, Mijung Park, Minsuk Gang
Open Journal of Nursing (OJN) , 2016, DOI: 10.4236/ojn.2016.611092
Abstract: The current study examined the effects of band therapy using music on grasping power, depression, and personal relationships among residents of a nursing home. Thirty subjects participated in the study. The band therapy included greetings, warm-up exercises with music, singing with dance, playing instruments, closing speech, and stretching with background music. Band therapy was held for 40 minutes once per week, for a total of four sessions, in the activity room of the nursing home. Findings showed that grasping power, depression, and personal relationships were improved at posttest, but the differences were not statistically significant. A better study design to compare the effects of band therapy with the other group, and a more simple and repeated intervention for the elderly to follow without stress might be necessary.
Acetylcholinesterase Inhibition by Flavonoids from Agrimonia pilosa
Mankil Jung,Moonso Park
Molecules , 2007, DOI: 10.3390/12092130
Abstract: In a bioassay-guided search for acetylcholinesterase (AChE) inhibitors from 180 medicinal plants, an ethyl acetate extract of whole plants of Agrimonia pilosa ledeb yielded tiliroside (1), 3-methoxy quercetin (2), quercitrin (3) and quercetin (4). We report herein for the first time that all four flavonol compounds showed significant inhibitory effects on AChE, particularly quercetin (4), which showed twice the activity of dehydroevodiamine (DHED).
New Record of a Aglaophenian Species (Hydrozoa: Thecatae: Plumulariidae) from Korea
Jung Hee Park
Animal Systematics, Evolution and Diversity , 2012, DOI: http://dx.doi.org/10.5635/ased.2012.28.2.145
Abstract: The hydroid specimens for this study were collected by SCUBA diving from about 15 m deep at the Isl. Marado, Jeju-do, Korea. Among the identified species Aglaophenia latecarinata Allman, 1877 was shown to be new to the Korean fauna. This species belongs to the family Plumulariidae which is the second large hydroid taxon in Korea. The distinct morphological characteristic of this species is the nine marginal teeth of hydrotheca, one median abcauline and four pairs laterals. Median abcauline tooth is bifid, with a broad keel extending along the front of the hydrotheca from its margin to the mesial inferior nematotheca, from which the species name was originated. Up to date four aglaophenian species of 35 plumularians have been reported from Korea.
Almost reverse lexicographic ideals and Fr?berg sequence
Jung Pil Park
Mathematics , 2009,
Abstract: We study almost reverse lexicographic ideals in a polynomial ring over a field of arbitrary characteristic. We give a criterion for a given sequence of nonnegative integers to be the Hilbert function of an almost reverse lexicographic ideal in the polynomial ring. Then it will be shown that every Fr\"{o}berg sequence satisfies this criterion.
Mineralization of Petroleum Contaminated Wastewater by Co-Culture of Petroleum-Degrading Bacterial Community and Biosurfactant-Producing Bacterium  [PDF]
Bo young Jeon, Il Lae Jung, Doo Hyun Park
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.27102
Abstract: Activity of a crude biosurfactant extracted from the culture fluid of Serratia sp. that was isolated from riverbed soil was shown to increase in proportion to the cultivation time, and was higher at pH 8 than at pH 7. Serratia sp. grew in the mineral-based medium with soybean oil but was not with kerosene-diesel. The petroleum-degrading bacteria—Acinetobacter sp., Pseudomonas sp., Paracoccus sp., and Cupriavidus sp.—were isolated from a specially designed enrichment culture. The efficiency of mineralization of wastewater contaminated with kerosene and diesel (WKD) by the petroleum-degrading bacterial community (PDBC) was enhanced significantly by addition of the crude biosurfactant. The efficiency of mineralization of the WKD was also about 2 times boosted by co-culture of Serratia sp. and PDBC. Bacterial community of Serratia sp. and PDBC co-cultivated in the WKD was maintained for at least 8 days according to the TGGE pattern of 16S rDNA obtained from the bacterial culture. In conclusion, the co-culture of Serratia sp. and PDBC is an applicable technique for the mineralization of wastewater contaminated with petroleum, which may substitute for chemical or biological surfactant.
Enrichment and Isolation of CO2-Fixing Bacteria with Electrochemical Reducing Power as a Sole Energy Source  [PDF]
Bo Young Jeon, Il Lae Jung, Doo Hyun Park
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.31007
Abstract: Enrichment of bacteria capable of growing with electrochemical reducing power and CO2 was accomplished using a plate-type electrochemical bioreactor (PEB). A bacterial source obtained from wastewater treatment reactant and forest soil was cultivated on carbonate-based mineral agar medium prepared in the PEB (PEB-carbonate agar). According to the pyrosequencing analyses, the abundance of Betaproteobacteria and Gammaproteobacteria at the phylum level, and Achromobacter, Alcaligenes, and Pseudomonas at the genus level were selectively increased after the electrochemical enrichment culture. Finally, one genus of bacterium that was autotrophically grown on the PEB-carbonate agar was identified as Alcaligenes. This bacterium may be useful to fix atmospheric CO2 with electrochemical energy obtained from the solar cell.
Conversion of Carbon Dioxide to Metabolites by Clostridium acetobutylicum KCTC1037 Cultivated with Electrochemical Reducing Power  [PDF]
Bo Young Jeon, Il Lae Jung, Doo Hyun Park
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.23040
Abstract: In this research, metabolic fixation of CO2 by growing cells of C. acetobutylicum cultivated with electrochemical reducing power was tested on the basis of the metabolites production and genes expression. In cyclic voltammetry, electrochemical oxidation and reduction reaction of neutral red (NR) immobilized in intact cells of C. acetobutylicum was stationarily repeated like the soluble one in the condition without CO2 but the electrochemical reduction reaction was selectively increased by addition of CO2. In electrochemical bioreactor, the modified graphite felt cathode with NR (NR-cathode) induced C. acetobutylicum to generate acetate, propionate, and butyrate from CO2 in defined medium. When H2 and CO2 were used as an electron donor and an electron acceptor, respectively, C. acetobutylicum also produced the same metabolites in a defined medium. C. acetobutylicum was not grown in the defined medium without substituted electron donors (H2 or electrochemical reducing power). C. acetobutylicum cultivated with electrochemical reducing power produced more butyrate than acetate in complex medium but produced more acetate than butyrate in defined medium. The genes of encoding the enzymes catalyzing acetyl-CoA in C. acetobutylicum electrochemically cultivated in defined medium than conventionally cultivated in complex medium. These results are a clue that C. acetobutylicum may metabolically convert CO2 to metabolites and produce free energy from the electrochemical reducing power.
Synthesis and Electrochemical Characterization of Li2MnSiO4 with Different Crystal Structure as Cathode Material in Lithium Rechargeable Batteries  [PDF]
Joongpyo Shim, Sora Won, Gyungse Park, Ho-Jung Sun
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B048
Abstract:

Li2MnSiO4 with different crystal structure was synthesized by solid state reaction method. Their crystal structure and electrochemical properties have been characterized by X-ray diffraction and charge-discharge test. The material prepared at 900oC in N2 atmosphere had γ-phase and its crystal structure changed to β-phase by post-heating at 400oC in air after 900oC sintering. In electrochemical measurement, two materials (γ- and β-phase) showed ~3 and ~45mAh/g, respectively. The different capacities of these two materials might be due to the change of crystal structure.



Finite Element Analysis of Tire Traction Using a Rubber-Ice Friction Model  [PDF]
Hyun Chul Jung, Woo Cheol Park, Kyoung Moon Jeong
Open Journal of Applied Sciences (OJAppS) , 2018, DOI: 10.4236/ojapps.2018.811040
Abstract: The friction of road surface covered by snow or ice is very low and that results in reducing vehicle traction forces and potential traffic accidents. In general, to establish a master curve on a rubber-ice friction model is difficult because the ice surface, being not far removed from its melting point, reacts itself very sen-sitively to pressure, speed, and temperature changes. In this paper, an accepta-ble frictional interaction model was implemented to finite element method to rationally examine the frictional interaction behavior on ice between the tire and the road surface. The formula of friction characteristic according to tem-perature and sliding velocity on the ice surface was applied for tire traction analysis. Numerical results were verified by comparing the outdoor test data and it was confirmed to indicate similar correlation. It is found that the rub-ber-ice friction model will be useful for the improvement of the ice traction performance of tire.
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