• Journal of Veterinary Clinics
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• v.23 no.4
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• pp.388-392
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• 2006

To verify the solitary nodular hepatocellular tumor model induced by intraparenchymal VX2 tumor cell injection and assess the diagnostic imaging character by computed tomography in rabbits. The tumor cell fragment ($1{\sim}2mm^3$) was loaded in Seldinger needle and directly implanted into the livers of 80 New Zealand white rabbits. The tumor size and patterns of tumor growth were evaluated using spiral computed tomography (CT) at 1, 2, and 3 weeks after tumor implantation. A solitary nodular tumor was successfully created in 82.5% (66/80). The mortality rate was 5% (4/80). The tumor sizes measured were 7.46.3, 14.210.8, 16.212.6 cm at 1, 2, and 3 weeks after tumor implantation on arterial phase CT images. The tumors were round to oval shape with peripheral enhancement and central hypoattenuation on arterial phase, and hypoatteuated wash-out pattern on portal phase. It is considered that inoculation of tumor fragment loaded in Seldinger needle is useful and practical method for creating a solitary hepatic tumor. And CT scanning are valuable to investigate the hepatic tumor and compatible to the observations on macro-and microscopic findings.

• Korean Journal of Remote Sensing
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• v.17 no.3
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• pp.231-242
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• 2001

In 2-pass differential SAR interferometry(DInSAR), the topographic phase signature can be removed by using a digital elevation model(DEM) to isolate the contribution of deformation from interferometric phase. This method has an advantage of no unwrapping process, but applicability is limited by precision of the DEM used. The residual phase in 2-pass differential interferogram accounts for error of DEM used in the processing provided that no actual deformation exits. The objective of this paper is a preliminary study to improve DEM precision using low precision DEM and 2-pass DInSAR technique, and we applied the 2-pass DInSAR technique to Asan area. ERS-1/2 tandem complex images and DTED level 0 DEM were used for DInSAR, and the precision of resulting DEM was estimated by a 1:25,000 digital map. The input DEM can be improved by simply adding the DInSAR output to the original low precision DEM. The absolute altitude error of the improved DEM is 9.7m, which is about the half to that of the original DTED level 0 data. And absolute altitude error of the improved DEM is better than that from InSAR technique, 15.8m. This approach has an advantage over the InSAR technique in efficiently reducing layover effects over steep slope region. This study demonstrates that 2-pass DInSAR can also be used to improve DEM precision.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.09a
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• pp.1-30
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• 1998

1. RO History 2. Asymmetric Membranes by Phase Inversion 3. Thin Film Composite (TFC) Membrane 4. Structure and Property Relationship of TFC Membrane 5. Membrane Materials 6. Tranport Mechanism(Model) 7. Membrane Characters in Separation Process 8. Concentration Polarization and Fouling Phenomenon 9. RO Membrane Module Configuration and System Design 10. Futrue Trend in RO Industry

• International Journal of Control, Automation, and Systems
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• v.4 no.2
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• pp.255-270
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• 2006

In this paper, a design method of nonlinear autopilot for ship-to-ship missiles is proposed. Ship-to-ship missiles have strongly coupled dynamics through roll, yaw, and pitch channel in comparison with general STT type missiles. Thus it becomes difficult to employ previous control design method directly since we should find three different solutions for each control fin deflection and should verify the stability for more complicated dynamics. In this study, we first propose a control loop structure for roll, yaw, and pitch autopilot which can determine the required angles of all three control fins. For yaw and pitch autopilot design, missile model is reduced to a minimum phase model by applying a singular perturbation like technique to the yaw and pitch dynamics. Based on this model, a multi-input multi-output (MIMO) nonlinear autopilot is designed. And the stability is analyzed considering roll influences on dynamic couplings of yaw and pitch channel as well as the aerodynamic couplings. Some additional issues on the autopilot implementation for these coupled missile dynamics are discussed. Lastly, 6-DOF (degree of freedom) numerical simulation results are presented to verify the proposed method.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.45.1-45.1
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• 2015

Hayabusa is the JAXA's space mission that succeeded in sample-return from S-type asteroid (25143) Itokawa. During the rendezvous phase, more than a thousand of images were taken with the Asteroid Multi-band Imaging Camera (AMICA). It is valuable to study the regional variation of the optical properties on the asteroid using these images to know the generality and uniqueness of the returned samples. In addition, AMICA images are important in that they provide unique data set at low phase angle (i.e Sun-Itokawa-AMICA's angle) that have not been explored in the previous asteroidal missions. At the previous conference (2015 KAS spring meeting), we introduced our preliminary data analysis of AMICA data without considering the shape model of Itokawa and mentioned. In this study, we present a new result obtained through further analysis, taking account of the shape model of the asteroid. We thus utilized "plate_renderer" tool to derive Hapke model parameters at different terrains. It is found that the opposition amplitude (parameter B0) is consistent with those of the other S-type asteroids while the opposition width (parameter h) is significantly narrower than those of the other S-type asteroids. At this conference, we plan to describe the regional variation of photometric properties on Itokawa.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1985-1992
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• 2011

The stable conformers of glycine and the inter-conversions between them were studied theoretically at various levels of theory, B3LYP, MP2, CCSD and CCSD(T), in the gas phase and in aqueous solution. In aqueous solution, the structures examined by use of the conductor-like polarizable continuum model (CPCM) with various cavity models, UA0, UAHF, UAKS, UFF, BONDI and PAULING, and by use of a discrete/continuum solvation model with eight water clusters. The Gibbs free energy differences between the neutral (NE) and zwitterionic conformers (ZW), ${\Delta}G_{Z-N}[=G_{ZW}-G_{NE}]$, in aqueous solution were well reproduced by using the BONDI and PAULING cavity models. However the ${\Delta}G_{Z-N}$ values were underestimated in other cavity models, although the ZW conformers existed as stable species in aqueous solution. In the studies of a discrete/continuum solvation model with eight water clusters, gas phase results are still insufficient to reproduce the experimental findings. However the ${\Delta}G_{Z-N}$ values calculated by use of CPCM method in aqueous solution agreed well with the experimental ones.

• Journal of Ocean Engineering and Technology
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• v.26 no.1
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• pp.9-16
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• 2012

This paper presents the numerical results of a simulation of the free surface flow around a blunt bow ship model and focuses on the validation of the proposed method with a brief investigation of the relation between the resistance and free surface behavior. A finite volume method based on the Reynolds Averaged Navier-Stokes (RANS) approach is used to solve the governing flow equations, where the free surface, including wave breaking,is captured by using a two-phase Level-Set (LS) method. For turbulence closure, a two equation k-${\varepsilon}$ model with the standard wall function technique is used. Finally, the numerical results are compared with the available experimental data, showing good agreement.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.221-226
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• 2000

In this study, the characteristics of gas-water relative permeability curves in a single fractured-plate according to the various aperture size were analyzed by using the Hele-Shaw type glass plate model. The plate was made of glasses for the observation of the two-phase flow pattern, and seven cases were set up based on the aperture size in the range of field scale from 30 to $120\mum$. The experiment was conducted by steady-state method, and the water saturation was determined more accurately by the developed digital image process technique. The empirical equations of relative permeability to gas and water for single fractured-plate were correlated by using the aperture size which directly affects the two-phase flow pattern and critical saturation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.233-239
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• 2003

The present study has numerically investigated the combustion processes in the solid propellant rocket engine. The two step global reaction model for condensed phase and five step global reaction mechanism for gas phase are adopted to predict the detailed flame structure near double-base solid propellant surface. The turbulence-chemistry interaction is represented by the PaSR(Partially Stirred Reactor) model. To reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect, the Low Reynolds number k-$\varepsilon$ turbulent model is employed. Based on numerical results, the detailed discussion has been made for the turbulent combustion processes and transient behavior of pressure and temperature fields in the solid propellant rocket engine.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.135-140
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• 1994

Over past decades, numerous in vitro model has been developed to investigate drug metabolism. In the order of complexity we found the isolated perfused liver, hepatocytes in co-culture with epithelial cells, hepatocytes in suspension and in primary culture and subcellular hepatic microsomal fractions. Because they can be easily prepared from both animals (pharmacological and toxicological species) and humans (whole livers as well as biopsies obtained during surgery) hepatocytes in primary culture provide the most powerful model to better elucidate drug behavior at an early stage of preclinical development such as : 1. the characterization of main biotransformation reactions. 2. the identification of phase I and phase II isozymes involved in such reactions 3. the evaluation of interspecies differences allowing the selection of a second toxicological animal species more closely related to man on the basis of metabolic profiles 4. the detection of the inducing and/or inhibitory effects of a drug on metabolic enzymes, the prediction of drug interactions 5. the estimation of inter-individual variability in biotransformation reactions. The use of hepatocytes, and in particular those obstained from humans, at an early stage of drug development allows the obtention of more predictive preclinical data and a better knowledge of drug behavior in humans before the first administration of the drug in healthy volunteers.