• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.315-321
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• 2010

Malassezia furfur is an important causal factor for seborrheic dermatitis. Nowadays, the drugs available to treat this fungal infection are few. Several studies have documented the biological activity of essential oils. However, its antifungal properties are not completely understood, especially its anti-Malassezia activity. The aim of this study were to evaluate the effect of the plant essential oils on the growth of M. furfur using disk diffusion method and analyze by Gas chromatography-mass spectrometry (GC-MS) most active essential oils. In first screening, the 17 plant essential oils have possesses inhibitory activity against M. furfur at 2 mg/mL. Among the plant essential oils, oil of Citrus auranifoli was most active against M. furfur and its activity showed dose dependency. This anti-malassezial activity was high than that of itraconazole at 2 mg/mL. Oil of Citrus auranifolia also was phytochemically examined by GC-MS analysis, its main constituents were identified as limonene, ${\gamma}$-terpinene and terpinolene. It can be concluded that essential oils of Citrus auranifolia may have interesting applications to control fungal-derived diseases.

• Clean Technology
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• v.24 no.3
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• pp.233-238
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• 2018

Bio-oil is produced by the fast quenching of hot vapor produced by fast pyrolysis of biomass in an inert atmosphere. Nitrogen is used as carrier gas to control the concentration of oxygen less than 3%. The consumption of nitrogen should be increased with increasing process size, and leading to increasing of facility and operating costs due to nitrogen charge. The effects of the recycling of non-condensable gases on the fast pyrolysis, bio-oil yield and quality, and nitrogen consumption have systematically investigated to see the possibility of these results in fast pyrolysis process of palm residue.

• Polymer(Korea)
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• v.26 no.3
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• pp.400-409
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• 2002

Polyurethane microcapsules containing functional oil (citronella oil) were successfully prepared by conventional interfacial polymerization of tolulene 2,4-diisocyanate (TDI) and ethylene glycol (EG) and characterized by Fourier transform (FT-IR) spectroscopy, Ultraviolet spectroscopy, particle size analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Tile effects of polymerization variables, such as surfactant concentration and agitation speed, on the particle size and particle size distribution were investigated. FT-IR spectroscopic data showed that citronella oil was successfully encapsulated in the microcapsule. Thermogravimetric analysis data showed that the microcapsule was thermally stable up to $220^{\circ}C$. The controlled release of the citronella oil present in the microcapsule core in a methanol medium was demonstrated by ultraviolet spectroscopy showing that the amount of released citronella oil was increased with increasing time. It was observed that the amount of released citronella oil was increased with increasing stirring speed and emulsifier concentration in the rnicrocapsule preparation step. Polyurethane microcapsules containing citronella oil showed excellent anti-moth property.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.482-486
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• 2005

The biodegradable poly(${\varepsilon}$-caprolactone)(PCL)/poly(ethylene imine)(PEI) microcapsules containing $Al_2O_3$ and fragrant oil were prepared with different PEI contents. The effects of stirring rate and concentration of the surfactant on the diameter and morphologies of microcapsules were investigated by using scanning electron microscope (SEM). Thermal behaviors were studied by using a differential scanning calorimetry(DSC), and the release behaviors of fragrant oil from microcapsule were characterized by UV/vis. spectrophotometer. As a result, the average particle size of the microcapsules decreased with increasing the stirring rate or concentration of the surfactant. The surface morphologies of the microcapsules were changed from smooth surfaces to skin-like rough surfaces as increasing the PEI content. These results were mainly due to the increased hydrophilic groups at the microcapsule surfaces, resulting in increasing the release rate of fragrant oil in the microcapsules studied.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.17-23
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• 2012

Large patch caused by Rhizoctonia solani AG2-2 (IV) is one of the most serious diseases in zoysiagrass. The objectives of this research were to evaluate the in vitro fungicidal effect and in field control of large patch disease of Paraffin oil. In the field experiments, paraffin oil was applied with 1 L/$m^2$ after diluted at 5 ml to 20 ml of oil/1 L of water for the control of large patch on Zoysia japonica in golf course. The same material was tested for inhibition of mycelial growth in vitro. Paraffin oil at 0.5% and 2.0% had a fungicidal effect by 43 to 67% on R. solani AG2-2 (IV) in vitro. In two locations of the field experiments, the paraffin oil provided moderate protection of large patch. It was effective in suppressing large patch development by 48.0% in comparison with a water check after one time application on mid-September in golf course. Paraffin oil may be used as an alternative control agent for environment friendly management of large patch on Zoysiagrass in golf course.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.271-276
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• 2008

The oil trap in oil separator is one of the most important characteristics for normal operation of compressor. In this study, oil separation characteristics has been investigated for $CO_2$/PAG mixture using a gravity type of oil separator. The experimental study has been carried out in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $0^{\circ}C$ to $15^{\circ}C$. The results obtained indicate that oil separation ratio in oil separator is increased with an increase in the oil concentration and mixture temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.8
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• pp.717-724
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• 2000

It is important to investigate characteristics of flow of refrigerant/oil mixture circulating in a refrigeration system. Therefore the oil concentration in refrigerant/oil mixture should be measured exactly by the adequate measuring instrument. In this paper, the oil concentration was measured by density monitoring system(DMS) in the liquid-line of a inverter-driven heat pump. Experimental result follows ; the main factor that have an effect on oil concentration refrigerant/oil mixture circulating in a refrigeration system is the momentum and kinematic viscosity of refrigerant/oil mixture compressed by scroll compressor.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.162-177
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• 2001

The hydrolysis rates of seven kinds of polyol ester base oils 〔POEs〕 of different branch shape were investigated by using a simple apparatus under mild acidic condition. Seven polyol ester base oils were made of poly hydric alcohols of two-four valence, normal or branched fatty acids of different carbon number. p-Toluene sulfonic acid was used as acid catalyst to accelerate the rate of hydrolysis. Partial esters and fatty acid produced by sequential hydrolysis of POEs were identified and their concentrations were determined by calibrated-internal standard method using Gas Chromatography. The rate constants of each step in sequential hydrolysis were determined by the least square method from rate equation and the concentration of each component, were compared with one another. It was shown that the rate of hydrolysis of POEs was strongly affected by whether molecular structure of fatty acid was straight chain or branch chain and which position was branched. The hydrolysis stability for all the POEs can be reasonably explained by using a steric hindrance effect anticipated fi:om their molecular structures affecting as water molecule makes an attack on the carbonyl carbon of POEs.

• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.56-67
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• 2019

The aim of this study was to investigate the influence of rosemary oil inhalation on memory, attention and autonomic nervous system according to the concentration difference in the aged. The research design was non-equivalent control group non-synchronized design. Participants were 89 individuals aged 65 or older who live in the community. Participants inhaled almond carrier oil(control group), 10%(experimental group A) and 100%(experimental group B) rosemary oil. Memory, attention, and autonomic nervous system responses were measured. Data were analyzed by SPSS win 24.0. The differences of the group and time were analyzed through repeated measure ANOVA. There were no significant differences in immediate recall (F=.42, p =.656), delayed recall (F=.45, p=.639), recognition (F=1.45, p=.242), digit span-forward (F=1.53, p=.223), digit span-backward (F=.46, p=.636), activities of sympathetic nerve system (LF)(F=.19, p=.828), activities of parasympathetic nerve system (HF)(F=.37, p=.694), LH/HF(F=1.39, p=.256), systolic blood pressure (F=.37, p=.694), diastolic blood pressure (F=1.25, p=.291). The inhalation of 10% and 100% rosemary oil for five minutes showed no significant effects on memory, attention and automatic nervous system in the aged.

• Journal of Convergence for Information Technology
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• v.10 no.4
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• pp.104-114
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• 2020

We investigated the best antibiotics using blending oils after screening 11 kinds of essential oil known as antibiotics from plants. The minimum inhibitory concentration (MIC) and the minimum killing concentration (MBC) were found to be essential for essential oils B and E to inhibit target bacteria. All gram-positive bacteria containing S. aureus used in this experiment were shown highly antibiotic activity. And only A. baumanii in gram-positive bacteria and C. albicans in fungi were shown highly antibiotic activity. The essential oils used in our experiments showed better antibiotic activity compared to major studies using natural antibiotics with excellent antibiotic activity and essential oils from natural medicine. It is not known what mechanism of antimicrobial activity the essential oil used in the test has, but it is interpreted as a synthetic inhibitory mechanism of cell wall compared with other previous studies. From these results, it is expected that some substances or functional products with antibiotic activity will be developed.