• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.2
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• pp.131-140
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• 2015

This research studied a scaling analysis for the selection of proper heat generation at tube for 1/4-scale storage vaults. First of all, the temperature field and velocity distribution of an original scale storage vault were analyzed and then numerical analysis of a 1/4-scale storage vault was performed to compare each model. The proper heat generation for a 1/4-scale storage vault, at which the temperature and velocity field of a 1/4-scale storage vault showed the best agreement with that of the original storage vault, was evaluated with proposed dimensionless parameters. The behavior of temperature and velocity of fluid in the 1/4-scale case were most similar to those of the original scale, using a heat flux 1.3 times higher than that seen in the original scale, which was approximately 190 W.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1612-1620
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• 2004

This study presents methods to estimate elastic-plastic crack opening displacement (COD) fur circumferential through-wall cracked pipes for the Leak-Before-Break (LBB) analysis of pressurized piping. Proposed methods are based not only on the GE/EPRI approach but also on the reference stress approach. For each approach, two different estimation schemes are given, one for the case when full stress-strain data are available and the other fur the case when only yield and ultimate tensile strengths are available. For the GE/EPRI approach a robust way of determining the Ramberg-Osgood (R-O) parameters is proposed, not only fur the case when detailed information on full stress-strain data is available but also for the case when only yield and ultimate tensile strengths are available. The COD estimates according to the GE/EPRI approach, using the R-O parameters determined from the proposed R-O fitting procedures, generally compare well with the published pipe test data. For the reference stress approach, the COD estimates according to the method based on both full stress-strain data and limited tensile properties are in good agreement with pipe test data. In conclusion, experimental validation given in the present study provides sufficient confidence in the use of the proposed method to practical LBB analyses even though when information on material's tensile properties is limited.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.555-567
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• 2013

A finite element formulation for a Rayleigh-damped Bernoulli-Euler beam subjected to support motions, which accompanies quasi-static rigid-body motion, is presented by using the quasi-static decomposition method. Moving support beam elements, one of whose nodes is coincident with the moving support, are developed to represent the effect of a moving support. Statically determinate beams subjected to support motions can be modeled successfully by using moving support elements. Examples of cantilever and simply-supported beams subjected to support motions are illustrated, and the numerical results are compared with the analytical solutions. The comparison shows good agreement.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.448-453
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• 2017

We conducted the three-dimensional fluid flow analysis in a Taylor reactor using computational fluid dynamics (CFD). The Taylor flow can be categorized into five regions according to Reynolds number, i.e., circular Couette flow (CCF), Taylor vortex flow (TVF), wavy vortex flow (WVF), modulated wavy vortex flow (MWVF), and turbulent Taylor vortex flow (TTVF), and we investigated the flow characteristics at each region. For each region, the shape, number and length of vortices were different and they influenced on the bypass flow. As a result, the Taylor vortex was found at TVF, WVF, MWVF and TTVF regions. The highest number of Taylor vortex was observed at TVF region, while the lowest at TTVF region. The numerical model was validated by comparing with the experimental data and the simulation results were in good agreement with the experimental data.

• BMB Reports
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• v.29 no.2
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• pp.175-179
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• 1996

Viral surface proteins are known to play an essential role in attachment of the virus particle to the host cell membrane. In case of the hepatitis B virus (HBV) several reports have described potential receptors on the target cell side, but no definite receptor protein has been isolated yet. As for the viral side, it has been suggested that the preS region of the envelope protein, especially the preS1 region, is involved in binding of HBV to the host cell. In this study, preS1 region was recombinantly expressed in the form of a maltose binding protein (MBP) fusion protein and used to identify and visualize the expression of putative HBV receptor(s) on the host cell. Using laser scanned confocal microscopy and by FACS analysis, MBP-preS1 proteins were shown to bind to the human hepatoma cell line HepG2 in a receptor-ligand specific manner. The binding kinetic of MBP-preS1 to its cellular receptor was shown to be temperature and time dependent. In cells permeabilized with Triton X-100 and treated with the fusion protein, a specific staining of the nuclear membrane could be observed. To determine the precise location of the receptor binding site within the preS1 region, several short overlapping peptides from this region were synthesized and used in a competition assay. In this way the receptor binding epitope in preS1 was revealed to be amino acid residues 27 to 51, which is in agreement with previous reports. These results confirm the significance of the preS1 region in virus attachment in general, and suggest an internalization pathway mediated by direct attachment of the viral particle to the target cell membrane.

• Journal of Korean Neurosurgical Society
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• v.29 no.2
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• pp.188-195
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• 2000

Objective : Essential tremor(ET) is the most common movement disorder, however, there has been little agreement in the neurologic literature regarding diagnostic criteria for ET. Familial ET is an autosomal dominant disorder presenting as an isolated postural tremor. The main feature of ET is postural tremor of the arms with later involvement of the head, voice, or legs. In previous studies, it was reported that ET susceptibility was inherited in an autosomal dominant inheritance. As previous results, it would suggest that ET might be associated with defect of mitochondrial or nuclear DNA. Recent studies are focusing on molecular genetic detection of movement disorders, such as essential tremor and restless legs syndrome. Moreover, authors have analysed mitochondrial DNA(mtDNA) from the blood cell of positive control(PC) and ET patients via long and accurate polymerase chain reaction(LA PCR). Materials & Methods : Blood samples were collected from PC and 9 ET patients. Total DNA was extracted twice with phenol followed by chloroform : isoamylalcohol. For the analysis of mtDNA, LA PCR was performed by mitochondrial specific primers. Results : With this technique, deletions of large quantities were detected within several regions of mtDNA in ET patients except for D-loop and CO I regions. Conclusion : The authors believe that ET is a genentic disorder with deficiency of mitochondrial DNA multicomplexes and mitochondiral dysfunction could be one of major causative factors of ET. Mitochondrial dysfunction may play an important role in the pathogenesis and possibility of disease progression among familial group with ET patients.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.1
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• pp.29-33
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• 1996

The eddy current test(ECT) probe of differential encircling coil type was designed and fabricated, and the optimum condition of ECT was derived for the examination of the irradiated fuel rod. The correlation between ECT test frequency and phase & amplitude was derived by performing the test of the standard rig that includes inner notches, outer notches and through-holes. The defect of through-hole was predicted by ECT at the G33-N2 fuel rod irradiated in the Kori-1 nuclear power reactor. The metallographic examination on the G33-N2 fuel rod was Performed at the defect location predicted by ECT. The result of metallographic examination for the G33-N2 fuel rod was in good agreement with that of ECT. This proves that the evaluation for integrity of irradiated fuel rod by ECT is reliable.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.5
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• pp.74-84
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• 1996

Dynamic loading of structures often causes excursions of stresses well into the inelastic range and the influence of geometric changes on the dynamic response is also significant in many cases. Therefore, both material and geometric nonlinearity effects should be considered in case that a dynamic load acts on the structure. For developing a program to analyze the dynamic response of an axisymmetric shell in this study, the material nonlinearity effect on the dynamic response was formulated by the elasto-viscoplastic model highly corresponding to the real behavior of the material. Also, the geometrically nonlinear behavior is taken into account using a total Lagrangian coordinate system, and the equilibrium equation of motion was numerically solved by a central difference scheme. A complete finite element program has been developed and the results obtained by it are compared with those in the references 1 and 2. The results are in good agreement with each other. As a case study of its application, the developed program was applied to a dynamic response analysis of a nuclear reinforced concrete containment structure. The results obtained from the' numerical examples are summarized as follows : 1. The dynamic magnification factor of the displacement and the stress were unrelated with the concrete strength. 2. As shown by the results that the displacement dynamic magnification factor were form 1.7 to 2.3 and the stress dynamic magnification factor from 1.8 to 2.5, the dynamic magnification factor of stress were larger than that of displacement. 3. The dynamic magnification factor of stress on the exterior surface was larger than that on the interior surface of the structure.

• Journal of Contemporary Eastern Asia
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• v.18 no.2
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• pp.90-117
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• 2019

How is science advice integrated in environmental policymaking? This is an increasingly pertinent question that is being raised since the nuclear catastrophe of Fukushima, Japan, in 2011. Global re-evaluation of energy policies and climate mitigation measures include discussions on how to better integrate science advice in policymaking, and at the same time keeping science independent from political influence. This paper addressed the policy discourse of setting up a national CO2 reduction target in Japanese policymaking between 2009 and 2012. The target proposed by the former DPJ government was turned down, and Japan lacked a clear strategy for long-term climate mitigation. The analysis provides explanations from a quantitative actor-network perspective. Centrality measures from social network analysis for policy actors in an environmental policy network of Japan were calculated to identify those actors that control the discourse. Data used for analysis comes from the Global Environmental Policy Actor Network 2 (GEPON 2) survey conducted in Japan (2012-13). Science advice in Japan was kept independent from political influence and was mostly excluded from policymaking. One of the two largest discourse coalitions in the environmental policy network promoted a higher CO2 reduction target for international negotiations but favored lowering the target after a new international agreement would have been set. This may explain why Japan struggled to commit to long-term mitigation strategies. Applying social network analysis to quantitatively calculate discourse coalitions was a feasible methodology for investigating "discursive power." But limited in discussing the "practice" (e.g. meetings, telephone, or email conversations) among the actors in discourse coalitions.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.93-99
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• 2016

Background: Industrial X-ray CT system is normally applied to non-destructive testing (NDT) for industrial product made from metal. Furthermore there are some special CT systems, which have an ability to inspect nuclear fuel assemblies or rocket motors, using high power and high energy (more than 6 MeV) pulsed X-ray source. In these case, pulsed X-ray are produced by the electron linear accelerator, and a huge number of photons with a wide energy spectrum are produced within a very short period. Consequently, it is difficult to measure the X-ray energy spectrum for such accelerator-based X-ray sources using simple spectrometry. Due to this difficulty, unexpected images and artifacts which lead to incorrect density information and dimensions of specimens cannot be avoided in CT images. For getting highly precise CT images, it is important to know the precise energy spectrum of emitted X-rays. Materials and Methods: In order to realize it we investigated a new approach utilizing the Bayesian estimation method combined with an attenuation curve measurement using step shaped attenuation material. This method was validated by precise measurement of energy spectrum from a 1 MeV electron accelerator. In this study, to extend the applicable X-ray energy range we tried to measure energy spectra of X-ray sources from 6 and 9 MeV linear accelerators by using the recently developed method. Results and Discussion: In this study, an attenuation curves are measured by using a step-shaped attenuation materials of aluminum and steel individually, and the each X-ray spectrum is reconstructed from the measured attenuation curve by the spectrum type Bayesian estimation method. Conclusion: The obtained result shows good agreement with simulated spectra, and the presently developed technique is adaptable for high energy X-ray source more than 6 MeV.