• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.568-574
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• 2000

Phytofluene was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector. Phytofluene was solubilized in 5% tween 40, and then oxidized by incubating under dim yellow light at 37$^{\circ}C$, 24 hr with continuous shaking. Carbonyl compound and acidic compound were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra were identical to the reference cleavage products prepared by ozeonolysis of phytofluene. Absorption spectrum of acidic compound was similar to that of standard 4,5-didehydrogeranyl geranyl acid which is known to possess biological activity. Thus, eccentric cleavage of phytofluene was confirmed to occur in vitro under oxidation condition.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.139-145
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• 2006

A previous study showed that the handle vibration of a walking type cultivator can be reduced by adding a mass to the handle. This study was conducted to determine the optimum magnitude and location of the mass to be added for the same cultivator. The possible locations of added mass were determined by investigating nodal points of the handle vibration by an ODS (operational deflection shapes) test at an engine frequency of 52 Hz. The optimum location was then determined as one that moved the nodal points to the hand grip of the handle bar. To determine the optimum magnitude of the mass, the possible locations were added by a mass from 0.2 to 2.0 kg in an increment of 0.2 kg. The optimum magnitude was then determined as a mass which minimized the vibration level at the hand grip. For the case of this study, the z-axis vibration at the hand grip was reduced from $2.67m/s^2\;to\;0.88m/s^2$ resulting in a reduction of 67% and the total vibration from $4.09m/s^2\;to\;3.27m/s^2$ resulting in a 20% reduction by adding an optimum mass to the optimum location.

• Journal of Powder Materials
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• v.4 no.3
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• pp.205-213
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• 1997

Mechanical alloying of $Ni_3Al$ and $Y_2O_3$ added ODS $Ni_3Al$ from elemental powders was investigated by the X-ray diffraction, differential scanning calorimeter, transmission electron microscopy and optical microscopy. The steady states of $Ni_3Al$ and ODS $Ni_3Al$ powders were reached after mechanical alloying with the condition of the ball-to-powder input ratio of 20:1 for 20 hours and 10 hours, respectively. The addition of nano-sized $Y_2O_3$ particles enhanced cold working and fracture, and subsequently accelerated MA of $Ni_3Al$ powders. DSC results of MAed $Ni_3Al$ powders showed four exothermic peaks at 14$0^{\circ}C$, 234$^{\circ}C$, 337$^{\circ}C$ and 385$^{\circ}C$. From the high temperature X-ray diffraction analysis, it was concluded that the peaks were resulted from the recovery solution of unalloyed Al in Ni, the formation of intermediate phase NiAl, and $LI_2$ ordering of MAed $Ni_3Al$ powders.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.1
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• pp.16-20
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• 2002

Parameter estimations were made for the reversed-phase adsorption of perillyl alcohol (POH), a potent anti-cancer agent, on octadecylsilyl-silica gel (ODS). The average particle diameter of ODS was about $15\;{\mu}m$, and the particles were packed in the column $(3.9\;\times\;300mm)$. The mobile phase used was a mixture of acetonitrile and water, in which the acetonitrile ranged between 50 and $70\;(v/v\;\%)$. The first absolute moment and the second central moment were determined from the chromatographic elution curves by moment analysis. Experiments were carried out using POH solutions within the linear adsorption range. The fluid-to-particle mass transfer coefficient was estimated using the Wilson-Geankoplis equation. The axial dispersion coefficient and the intra particle diffusivity were determined from the slope and intercept of a plot of H vs $1/u_0$, respectively. The contributions of each mass-transfer step were axial dispersion, fluid-to-particle mass transfer, and intraparticle diffusion.

• Nuclear Engineering and Technology
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• v.40 no.2
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• pp.99-106
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• 2008

Through mechanical alloying, hot isostatic pressing and hot rolling, a 9%Cr Fe-based oxide dispersion-strengthened alloy sample was fabricated. The tensile strength of the alloy is significantly improved when the microstructure is modified during the post-consolidation process. The alloy samples were strengthened as the cooling rates increased, though the elongation was somewhat reduced. With a cooling rate of $800^{\circ}C/s$ after normalization at $1150^{\circ}C$, the alloy sample showed a tensile strength of 1450 MPa, which is about twice that of the hot rolled sample; however, at $600^{\circ}C$ the tensile strength dramatically decreased to 620 MPa. Optical microscope and transmission electron microscope were used to investigate the microstructural changes of the specimens. The resultant strengthening of the alloy sample could be mainly attributed to the interstitially dissolved nitrogen, the fraction of the tempered martensite, the fine grain and the presence of a smaller precipitate. The decrease in the tensile strength was mainly caused by the precipitation of vanadium-rich nitride.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.830-833
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• 2004

An indoor package air-conditioner (PAC) has complex noise sources such as motor noise and fluid noise caused by the fan motor, heat transfer and shroud. Sound intensity techniques and ODS(Operational deflection shape) techniques are applied to identify the noise characteristics of an indoor air-conditioner's cabinet. The sound intensity is used to visualize the noise source locations. and the ODS to visualize the vibration pattern and to obtain the dynamic characteristics of the noise source. Acoustic intensity and operational deflection distribution are obtained in space domains as well as frequency domains. Using the visual information of source locations and its dynamic characteristics, the damping patch is applied to reduce structure borne noise in the cabinet. As a result, the noise emitted by the cabinet is reduced by 5dB.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1145-1148
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• 2002

Melatonin, which is a hormone secreted from pineal gland of brain and known to prevent oxidative damages of various tissues, was analyzed in 26 domestic edible plants. For the preparation of melatonin fraction, 50% ethanol extract prepared from lyophilized plant powder was filtered and applied on TLC plate. Melatonin position on TLC developed with acetone was identified by fluorescence light and extracted with methanol. This methanolic fraction was injected into HPLC comprising ODS-A column, fluorescence detector, and mobile phase consisting of a mixture (30 : 70, v/v) of 70% ammonium acetate and methanol at a flow rate of 1.0 mL/min. Melatonin was identified at the retention time of 17 min. Results revealed that celery, leek, broccoli, and cauliflower had higher melatonin contents than others.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1227-1233
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• 2000

Lycopene was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector and by LC-MS. UV-vis spectra and $[M+H]^+$ of the carbonyl compound peaks showed clearly that acycloretinal, apo-14'-lycopenal, apo-12'-lycopenal, apo-10'-lycopenal, apo-8'-lycopenal and apo-6'-lycopenal were formed by ozonolysis of lycopene. Lycopene was solubilized in toluene and aqueous Tween 40, and then oxidized by incubating at $37^{\circ}C$ under atmospheric oxygen. Carbonyl compounds were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra are identical to the reference cleavage products prepared by ozonolysis of lycopene. Thus, eccentric cleavage of lycopene was confirmed to occur in vitro under oxidation condition.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.75-79
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• 1992

Differences in chromatographic properties in RPLC of four brands of cyano bonded silica stationary phases are rationalized in terms of the type and relative strength of the solute-stationary phase interactions, which can be readily inferred from multiple linear regression analyses of retention data for a set of standard compounds on the stationary phases under study based on the linear solvation energy relationships (LSERs). Although four brands of cyano bonded columns studied (CPS-Hypersil, Ultrasphere cyano, Spherisorb-CN and ${\mu}$-Bondapak-CN) have similar bonding density and have been prepared from monofunctional cyanopropylsilane reagents, they possess quite different, relative hydrogen bonding (HB) donor and acceptor strengths. Comparison of the retention behavior on a cyano-bonded silica column with that on an ODS column shows that there are significant differences in the strength of HB interactions between the solute and the stationary phase on the two columns with different functionalities. Information on the differences in the interaction characteristics among brands of the cyano-bonded silica columns and between the ODS and cyano-bonded columns can be utilized to optimize the selectivity for a given separation on these columns.

• Journal of Powder Materials
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• v.28 no.5
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• pp.375-380
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• 2021

In this study, we investigate the effect of the duration of mechanical alloying on the microstructures and mechanical properties of ODS ferritic/martensitic steel. The Fe(bal.)-10Cr-1Mo pre-alloyed powder and Y₂O₃ powder are mechanically alloyed for the different mechanical alloying duration (0 to 40 h) and then constantly fabricated using a uniaxial hot pressing process. Upon increasing the mechanical alloying time, the average powder diameter and crystallite size increased dramatically. In the initial stages within 5 h of mechanical alloying, inhomogeneous grain morphology is observed along with coarsened carbide and oxide distributions; thus, precipitate phases are temporarily observed between the two powders because of insufficient collision energy to get fragmented. After 40 h of the MA process, however, fine martensitic grains and uniformly distributed oxide particles are observed. This led to a favorable tensile strength and elongation at room temperature and 650℃.