• Proceedings of the KSME Conference
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• 2001.06c
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• pp.251-256
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• 2001

Deformation analysis of injection molded articles whose geometry is considered as the assembly of the thin flat plates has been conducted. For the in-mold analysis, thermo-viscoelastic stress calculation of rheologically simple amorphous polymer and in-mold deformation calculation considering the in-plane mold constraint has been done. Free volume theory has been used for the non-equilibrium density state by the fast cooling. At ejection, the redistribution of stress together with instantaneous deformation has been considered. During out-of-mold cooling after ejection, thermoelastic model based on the effective temperature has been adopted for the calculation of deformation. Two typical mold geometries are used to test the numerical simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.735-745
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• 2004

A linear cascade of NACA 65-1810 profiles are investigated for tip leakage flow characteristics. and calculation results are compared with experimental result. STAR-CD commercial code was used to solve the three dimensional incompressible Navier-Stokes equation that was adopted for steady flow and high Reynolds $\kappa$- $\varepsilon$turbulent model. Numerical calculation of a linear cascade is carried out to investigate effect of tip clearance on pitchwise variations of velocity Profiles. and static pressure distributions on the blade surface at spanwise positions. In case of evolution of tip vortex core location. tip vortex geometry and static pressure at the center of the tip vortex core compared with experimental results. Calculation results are agreed well with the experimental data, and validated. The static pressure losses by tip leakage flow at 2% tip clearance were more than those at 1% tip clearance.

• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1998-2004
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• 2019

The Multi-Physics (MP) instrument is one of 20 neutron spectrometers planned in the China Spallation Neutron Source (CSNS). This paper presents a shielding calculation for the MP instrument using Monte Carlo codes MCNPX and FLUKA. First, the neutrons that escape from the CSNS decoupled water moderator and are delivered to the beam line of the MP instrument are calculated to use as the source term of the shielding calculation. Then, to validate the calculation method based on multiple variance reduction techniques, a cross check between MCNPX and FLUKA codes is performed by comparing the calculation results of the dose rate distribution on a simplified beam line model. Finally, a complete geometry model of the MP instrument is set up, and the primary parameters for the shielding design are obtained according to the calculated dose rate map considering different worst-case scenarios.

• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.1-8
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• 1998

Molecular electrostatic potential (MEP) of the thiazole, relevant to the binding of lexitroposin that contains thiazole ring to the base pair of minor groove of DNA is obtained from the results of ab initio calculation. The geometry optimization for the two possible conformations of protonated thiazoles is performed with the aid of MNDO and ab initio calculations. The proton affinities are calculated at the 6-31G and 6-31G basis set for the optimized geometry. The proton affinities are also studied for various substituted thiazoles with the electron-donating and electron-withdrawing groups to estimate substituent effect on the proton affinity of thiazoles. It is found that the thiazole with nitrogen atom aligned inward to the DNA minor groove exhibit higher proton affinity and electron-donating substituents increase the proton affinity of thiazoles.ĀȀꃏ?⨀缾ĀȀ會ĀȀ?⨀ꖓĀĀȀ會ĀȀ僐?⨀聥ꖓĀĀȀ會ĀȀ꣐?⨀聐缾ĀȀ會ĀȀÑ?⨀ၑ缾ĀȀ會ĀȀ壑?⨀ꁑ缾ᨀĀꀏ會Āꀏ냑?⨀⡒缾᐀Āꀏ會Āꀏ࣒?⨀끒缾ᰀĀꀏ會Āꀏ惒?⨀ꁩꖓȀĀꀏ會Āꀏ룒?⨀⡪ꖓሀĀꀏ會Āꀏდ?⨀ᤐ돀삺?⨀塨?⨀飣?⨀돐룣?⨀偠잖⨀샣?⨀줏덐탣?⨀젏ꠏܞ
Ȍ蠀
ᥲ⴯

ͧ
Molecua及컲ࡔ
ȏᰗۊऀں
Molecular electrostatic potential (MEP) of the thiazole, relevant to the binding of lexitroposin that contains thiazole ring to the base pair of minor groove of DNA is obtained from the results of ab initio calculation. The geometry optimization for the two possible conformations of protonated thiazoles

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.1-8
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• 2017

The purpose of this study is to propose a cache structure for processing large-volume building information modeling (BIM) geometry data,whereit is difficult to allocate physical memory. As the number of BIM orders has increased in the public sector, it is becoming more common to visualize and calculate large-volume BIM geometry data. Design and review collaboration can require a lot of time to download large-volume BIM data through the network. If the BIM data exceeds the physical free-memory limit, visualization and geometry computation cannot be possible. In order to utilize large amounts of BIM data on insufficient physical memory or a low-bandwidth network, it is advantageous to cache only the data necessary for BIM geometry rendering and calculation time. Thisstudy proposes acache structure for efficiently rendering and calculating large-volume BIM geometry data where it is difficult to allocate enough physical memory.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.77-87
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• 1994

This paper deals with an automated forming sequence design system by which designers can determine desirable operation sequences even if they have little experience in the design of cold forging process. The forming sequence design in the cold forging is very important and requires many kinds of technical and empirical knowledge. They system isproposed, which generates forming sequence plans for the multistage cold forging of axisymmtrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning process. To recognize the geometry of the product section, section entity representation and primitive geometries were used. Section entity representation can be used for the calculation of maximum diameter, maximum height, and volume. Forming sequence for the part can be determined by means of primitive geometries such as cylinder, cone, convex, and concave. By utilizing this geometrical characteristics (diameter, height, and radius), the product geometry is expressed by a list of the priitive geometries. Accordingly the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. Based on the results of forming sequence, process variables(strain, punch pressure, die inner pressure, and forming load) are determined.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.526-532
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• 2019

In this study, an in-house $^{152}Eu$ calibration source was produced from a custom epoxy matrix with a density of ${\rho}=1.14g\;cm^{-3}$, which is chemically stable and durable form after its solidification. The homogeneity of $^{152}Eu$ in matrix was obtained better than 98%. For a Marinelli beaker geometry, an efficiency calibration procedure was applied to a n-type, coaxial, 78.5% relative efficient HPGe detector in the energy range of 121.7-1408.0 keV by using in-house $^{152}Eu$ calibration source. Then the measured efficiencies for Marinelli geometry were compared with the results calculated by MEFFTRAN and ANGLE softwares for the validation. Although MEFFTRAN and ANGLE have two different efficiency transfer algorithms to calculate the efficiencies, they usually need to use a reliable and accurate reference efficiency values as input data. Hence, reference efficiency values were obtained experimentally from a multinuclide standard source for the same detector-Marinelli geometry. In the present source characterization, the corrections required for self-absorption and true coincidence summing effects for $^{152}Eu$ gamma-rays were also obtained for a such close counting geometry condition. The experimental results confirmed the validity of efficiency calculations obtained by MEFFTRAN and ANGLE softwares that are calculation tools.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.788-798
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• 2005

The monopole theory has long been used to model air-pumped effect from the elastic cavities in car tire. This approach models the change of an air as a Piston moving backward and forward on a spring and equates local air movements exactly with the volume changes of the system. Thus, the monopole theory has a restricted domain of applicability due to the usual assumption of a small amplitude acoustic wave equation and acoustic monopole theory This paper describes an approach to predict the air-pumping noise of a car tyre with CFD/Kirchhoff integral method. The tyre groove is simply modeled as piston-cavity-sliding door geometry and with the aid of CFD technique flow properties in the groove of rolling car tyre are acquired.'rhese unsteady flow data are used as a air-pumping source in the next CFD calculation of full tyre-road geometry. Acoustic far field is predicted from Kirchhoff integral method by using unsteady flow data in space and time which is provided by the CFD calculation of full tyre-road domain. This approach can cover the non-linearity of acoustic monopole theory with the aid of Non-linear governing equation in CFD calculation. The method proposed in this paper is applied to the prediction of air-pumping noise of simply modeled car tyre and through the predicted results, the influence of nonlinear effect on air-pumping noise propagation is investigated.

• Nuclear Engineering and Technology
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• v.20 no.4
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• pp.233-240
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• 1988

The hafnium shroud is used to control the excess reactivity and power distribution in KMRR. The core analysis is performed by the diffusion code VENTURE using the 5 group macroscopic cross sections homogenized for an assembly. Investigated are the applicability of the diffusion calculation by homogenized cross sections to the analysis of control assembly which features unusual geometry such that hafnium shroud surrounds a multiplying medium inside. Comparative calculation is performed for the excess reactivity and power levels by the transport code TWOTRAN. The results show the acceptability of the diffusion calculation by the homogenized cross sections without significant error.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.6
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• pp.725-734
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• 1997

The effect of helical intake port geometry on in-cylinder swirl flow characteristics was studied. Two helical intake ports were selected to change swirl ratio, mean flow coefficient with the variation of valve lifts, valve eccentricity ratios and axial distance. The measurements were made by using an impulse swirl meter. The port B modified to increase the swirl ratio( $R_{s}$) had the tendency of the increased non-dimensional rig swirl ( $N_{r}$) distribution in comparison with that of the port A. And the $N_{r}$ distribution was remarkably improved at low valve lifts. The modification of the geometry to increase the swirl ratio ( $R_{s}$) in helical intake port resulted in the decrease of the mean flow coefficient ( $C_{f(mean)}$) regardless of valve eccentricity ratio ( $N_{y}$). And also non-dimensional rig swirl ( $N_{r}$) in the high valve lift affected the calculation of swirl ratio considerably.onsiderably.