• Nuclear Engineering and Technology
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• v.46 no.2
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• pp.147-158
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• 2014

In order to investigate how the microstructure of fuel/matrix-interaction (FMI) layers change during irradiation, different U-7Mo dispersion fuel plates have been irradiated to high fission density and then characterized using scanning electron microscopy (SEM). Specifially, samples from irradiated U-7Mo dispersion fuel elements with pure Al, Al-2Si and AA4043 (~4.5 wt.%Si) matrices were SEM characterized using polished samples and samples that were prepared with a focused ion beam (FIB). Features not observable for the polished samples could be captured in SEM images taken of the FIB samples. For the Al matrix sample, a relatively large FMI layer develops, with enrichment of Xe at the FMI layer/Al matrix interface and evidence of debonding. Overall, a significant penetration of Si from the FMI layer into the U-7Mo fuel was observed for samples with Si in the Al matrix, which resulted in a change of the size (larger) and shape (round) of the fission gas bubbles. Additionally, solid fission product phases were observed to nucleate and grow within these bubbles. These changes in the localized regions of the microstructure of the U-7Mo may contribute to changes observed in the macroscopic swelling of fuel plates with Al-Si matrices.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.709-716
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• 2015

In this study, structural developments of polypropylene / ionomer / clay ternary composites were investigated depending on the dispersion and localization of clay. The changes in physical properties were observed adding organoclays 1~10wt% to 90% polypropylene and 10% ionomer blends. The organoclays were localized inside of the dispersed phase under the composition of 3wt%, however, over that composition, clay particles formed stiff network structure in the dispersed phase and additional clays were localized at the interface between two phases. According to the developments of microstructure, the interaction of ternary composites changed from polypropylene-ionomer to polypropylene-ionomer and ionomer-clay which affected rheological properties. The storage modulus (G') of the composites was similar to the blends when clays were localized inside of dispersed phase but increased when clays were localized at interface. Also, the fractured morphology of the composites showed phase boundary and growing radius of dispersed phase depending on addition of fillers when clays were found inside. However, when fillers found at the interface between blends, the radius of the dispersed phase decreased and compatibilized morphology were observed. The interfacial interaction of the ternary composite was quantified depending on the structural development of dispersed phase and localization of clay particles by the rheological properties. The interaction of composites at solid state which was measured through peel adhesion strength increased by growth of interfacial interaction of each component. Furthermore, the crystallinity of the composites was decreased when the clay particles were localized at the interface.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.30-37
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• 2001

Most gasoline engines employ a port injection system to achieve the better fuel-air mixing. A part of injected fuels adheres to the wall or intake valve and forms a film of liquid fuel. The other is secondarily atomized by the spray-wall interaction. A better understanding of this interaction will help in designing injection systems and controlling the strategies to improve engine performance and exhaust emissions. In the present research, the spray-wall interaction was investigated by a laser sheet visualization method. The shape of sprays was pictured at various impinging velocities and angles. The fuel dispersion was estimated by fluorescence light, and the atomization was evaluated by the enlarged images of droplets. The experimental results were compared with model predictions which are based on OPT method. The model has been modified to have the better agreement with the experimental result, and was implemented in the KIVA-II code.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.199-204
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• 2008

The generation of axisymmetric Lamb waves and interaction with wall thinning (corrosion) defects in hollow cylinders are simulated using the finite element method. Guided wave interaction with defects in cylinders is challenged by the multi-mode dispersion and the mode conversion. In this paper, two longitudinal, axisymmetric modes are generated using the concept of a time-delay periodic ring arrays (TDPRA), which makes use of the constructive/destructive interference concept to achieve the unidirectional emission and reception of guided waves. The axisymmetric scattering by the wall thinning extending in full circumference of a cylinder is studied with a two-dimensional FE simulation. The effect of wall thinning depth, axial extension, and the edge shape on the reflections of guided waves is discussed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.4 s.117
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• pp.47-52
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• 2006

This study is about the effect from properties of coated paper and ink dispersion to the printed mottle. Ink receptivity would be expected that it is mainly effected by roughness of coated paper Because the transfer of ink can not be uniform with rough surface, it will cause the optical appearance such like printed mottle. And also it may be able to cause the printed mottle from uneven transfer of ink due to absorption property of based paper, depend on size degree, by using dampening in Off-set printing. Each different specific of surface and ink dispersion could cause printed mottle. Therefore this study was carried out by using densitometer and image analysis to show the interaction between properties of domestic coated paper and ink dispersion.

• Korean Journal of Pharmacognosy
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• v.15 no.4
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• pp.206-212
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• 1984

The effect of saponin fractions of Panax ginseng root on the interactions of human plasma lipoproteins and lecithin dispersions with dextran sulfate were studied in order to examine the effect of Panax ginseng on the lipid accumulation in the aorta. The total saponin fraction and protopanaxadiol glycosides of Panax ginseng root seemed to slightly enhance the interaction of low density lipoproteins with dextran sulfate in the absence of divalent metal ions. Protopanaxatriol glycosides remarkably inhibited the interaction of low density lipoproteins with dextran sulfate. However, all of these three saponin fractions of Panax ginseng root showed the tendency of inhibition to the interaction of high density lipoproteins with dextran sulfate in the presence of divalent metal ions by the order of protopanxatriol glycosides, protopanaxadiol glycosides and total saponin. Three saponin fractions of Panax ginseng exerted almost same tendency to the interaction of lecithin dispersions with dextran sulfate in the presence of divalent metal ions as the interaction of low density lipoproteins with dextran sulfate absence of divalent metal ions.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.173-179
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• 2002

Solid dispersions of ipriflavone with PVP were prepared by a spray-drying method in order to improve the bioavailability. They were measured with scanning electron microscopy, differential scanning calorimetry, x-ray powder diffraction, and Fourier transform infrared spectroscopy to evaluate the physicochemical interaction between ipriflavone and PVP and study the correlation between these physicochemical characteristics and bioavailability. Ipriflavone exhibited crystallinity, whereas PVP was almost amorphous. The area of the endotherm $({\Delta}H)$ of freezer milled ipriflavone, freezer milled ipriflavone physically mixed with freezer milled PVP, and physically mixed ipriflavone with PVP was almost the same, whereas ${\Delta}H$ of the solid dispersed ipriflavone with PVP was much smaller than that of the other preparation types. Also, the crystallinity and the crystal size of ipriflavone in the solid dispersed ipriflavone with PVP were much smaller than those of the other preparation types. From the in vivo test, the AUC of the solid dispersed ipriflavone with PVP was approximately 10 times higher than that of the physically mixed ipriflavone with PVP. The solid dispersion using the spray-drying method with a water-soluble polymer, PVP, may be effective for the improvement of the bioavailability.

• Journal of the Korean Ceramic Society
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• v.36 no.2
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• pp.210-219
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• 1999

The fundamental dispersion property of Si2N4 and a combination of AlN and Nd2O3 as sintering additives in a variety of organic solvents such as alcohols, hydrocarbons, ketones, and ethers was investigated. The stabilization mechanism and interaction between organic functional groups of the various organic additives were studied to clarify the dispersibility of the ceramic particles in the nonaqueous suspending medium. characterization of the suspensions was based mainly on electrokinetic sonic amplitude(ESA) measurements and the flow curves obtained from the rheological studies as well as estimated Hamaker constants. It was found that the contribution of electrostatic repulsive forces to the Si3N4, AlN and Nd2O3 stabilization in organic media is appreciably greater than anticipated and is dependent on the physicochemical properties of organic solvents.

• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.132-139
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• 2011

We investigate theoretically the combined effect of fiber chromatic dispersion and self-phase modulation (SPM) on multi-channel subcarrier multiplexed (SCM) optical transmission systems in terms of the detected RF carrier power and SPM-induced power gain after transmission over single-mode fiber (SMF) links. According to the calculated power gain due to the SPM effect at the transmission distance of P3dB using the detected radio-frequency (RF) carrier power after photo-detection, the power gain is significantly degraded with large optical modulation index (OMI), small SCM channel spacing, and large fiber launching power because of the increased interaction between subcarrier channels. The nonlinear phase shift due to linear and nonlinear fiber characteristics is investigated to explain these results in detail. The numerical simulation results show that the OMI per SCM channel has to be smaller than 10 % for the fiber launching power of 10 dBm to guarantee prevention of SPM-induced power gain degradation below 0.5 dB for the SCM system with the channel spacing of 100 MHz. This result is expected to be utilized for the optical transmission systems using the SCM technology in future radio-over-fiber (RoF) networks.

• Journal of the Korean Chemical Society
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• v.40 no.5
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• pp.317-326
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• 1996

The frequency dependent longitudinal polarizabilities ${\alpha}zz(\omega)$ and the second hyper-polarizabilities ${\gamma}zzzz(\omega)$ of the linear polyenes, $C_4H_6\;to\;C_{30}H_{32}$, have been evaluated using the ab initio time-dependent coupled perturbed Hartree-Fock (TDCPHF) theory with the 6-31G basis set. The ratios of the dynamic properties to the static values have been examined to illustrate the relative dispersion effect and extrapolated to the infinite polymer limit. Also the effect of interchain interaction for linear and nonlinear optical properties has been investigated for $C_4H_6$ and the theoretical discussion has been described to overcome the limitation of ab initio TDHF method in the resonance region.