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A Study on the Optimal Crimping Diameter of Aircraft Fuel Hoses in Manufacturing Process (항공기용 연료호스 제작시 최적 크림핑 직경에 관한 연구)

  • Jeon, Jun-Young;Kim, Byung-Tak
    • Journal of Power System Engineering
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    • v.18 no.1
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    • pp.84-90
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    • 2014
  • The high pressure hoses are widely used for the vehicles, aircraft, and overall industries. The hose assembly is generally composed of a nipple, a socket and a hose with reinforcement layers to increase the tensile strength. To produce the hose assembly, crimping or swaging process is usually used to clamp its components to ensure the prevention of fluid leakage. Crimping is a cold-working technique to form a strong bond between the workpiece and a non-metallic component. The crimping stroke is a primary parameter to be determined in the metalworking process, and it plays an important role in hose performance. This study aims at investigating the optimal crimping stroke according to the size of aircraft high pressure hose by using MSC/MARC. It is supposed that the results can be useful to get the information about the crimping stroke in manufacturing process, even with the different size of a hose.

ASIC2a-dependent increase of ASIC3 surface expression enhances the sustained component of the currents

  • Kweon, Hae-Jin;Cho, Jin-Hwa;Jang, Il-Sung;Suh, Byung-Chang
    • BMB Reports
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    • v.49 no.10
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    • pp.542-547
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    • 2016
  • Acid-sensing ion channels (ASICs) are proton-gated cation channels widely expressed in the nervous system. Proton sensing by ASICs has been known to mediate pain, mechanosensation, taste transduction, learning and memory, and fear. In this study, we investigated the differential subcellular localization of ASIC2a and ASIC3 in heterologous expression systems. While ASIC2a targeted the cell surface itself, ASIC3 was mostly accumulated in the ER with partial expression in the plasma membrane. However, when ASIC3 was co-expressed with ASIC2a, its surface expression was markedly increased. By using bimolecular fluorescence complementation (BiFC) assay, we confirmed the heteromeric association between ASIC2a and ASIC3 subunits. In addition, we observed that the ASIC2a-dependent surface trafficking of ASIC3 remarkably enhanced the sustained component of the currents. Our study demonstrates that ASIC2a can increase the membrane conductance sensitivity to protons by facilitating the surface expression of ASIC3 through herteromeric assembly.

Tight Junction Assembly Ensures Maintenance of Pregnancy during Embryogenesis in a Mouse Model

  • Jeong, Yelin;Choi, Inchul
    • Journal of Animal Reproduction and Biotechnology
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    • v.34 no.4
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    • pp.318-321
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    • 2019
  • Recent studies showed that tight junctions (TJs) integrity and assembly are required for blastocyst development in mouse and pig models. However, the biological functions of TJs associated with embryo implantation and maintenance of pregnancy were not investigated yet. To examine whether disrupted TJs affect further embryo development, we employed RNAi approach and inhibitor treatment. The embryos were injected with Cxadr (Coxsackievirus and adenovirus receptor) siRNA for knock down (KD) and treated with Adam10 (A Disintegrin and Metalloproteinase specific inhibitor 10; GI254023X; SI). We compared blastocyst development and paracellular sealing assay using FITC dextran uptake between control and KD or SI embryos. Finally, we transferred control and Cxadr KD or Adam 10 SI treated blastocyst to uteri of recipients. Cxadr KD and Adam 10 SI showed lower blastocyst development and more permeable to FITC-dextran. Moreover, we observed that half of KD and inhibited embryos failed to maintain pregnancies after the second trimester. Our findings suggested that TJs integrity is required for the maintenance of pregnancy and can be used as a selective marker for the successful application of assisted reproduction technologies.

Monte Carlo Analysis of the Accelerator-Driven System at Kyoto University Research Reactor Institute

  • Kim, Wonkyeong;Lee, Hyun Chul;Pyeon, Cheol Ho;Shin, Ho Cheol;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.48 no.2
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    • pp.304-317
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    • 2016
  • An accelerator-driven system consists of a subcritical reactor and a controllable external neutron source. The reactor in an accelerator-driven system can sustain fission reactions in a subcritical state using an external neutron source, which is an intrinsic safety feature of the system. The system can provide efficient transmutations of nuclear wastes such as minor actinides and long-lived fission products and generate electricity. Recently at Kyoto University Research Reactor Institute (KURRI; Kyoto, Japan), a series of reactor physics experiments was conducted with the Kyoto University Critical Assembly and a Cockcrofte-Walton type accelerator, which generates the external neutron source by deuteriu-metritium reactions. In this paper, neutronic analyses of a series of experiments have been re-estimated by using the latest Monte Carlo code and nuclear data libraries. This feasibility study is presented through the comparison of Monte Carlo simulation results with measurements.

Oligomeric Structure of ${\beta}$-Glucosidases

  • Kim, Sang-Yeob;Kimm, In-Soo
    • Journal of Photoscience
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    • v.11 no.3
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    • pp.121-127
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    • 2004
  • The${\beta}$-glucosidases occur widely in all living organisms and has in general a tendency to form oligomers of varying numbers of subunits or aggregates, although the functional implications of such diverse oligomerization schemes remain unclear. In particular, the assembly mode of the oat ${\beta}$-glucosidase is very unique in that it multimerizes by linear stacking of a hexameric building block to form long fibrillar multimers. Some structural proteins such as actin and tubulin assemble into long fibrils in a helical fashion and several enzymes such as GroEL and Pyrodictium ATPase functional complexes, 20S proteasome of the archaebacterium Thermoplasma acidophilum, and lutamine synthetase fromblue-green algae, assemble into discrete oligomers upto 4 stacked rings to maintain their enzymatic activities. In particular, oat ${\beta}$-glucosidase exists in vivo as a discrete long fibrillar multimer assembly that is a novel structure for enzyme protein. It is assembled by linear stacking of hollow trimeric units. The fibril has a long central tunnel connecting to the outer medium via regularly distributed side fenestrations. The enzyme active sites are located within the central tunnel and multimerization increases enzyme affinity to the substrates and catalytic efficiency of the enzyme. Although it is suggested that oligomerization may contribute to the enzyme stability and catalytic efficiency of ${\beta}$-glycosidases, the functional implications of such diverse oligomerization schemes remain unclear so far.

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Numerical investigation on vortex behavior in wire-wrapped fuel assembly for a sodium fast reactor

  • Song, Min Seop;Jeong, Jae Ho;Kim, Eung Soo
    • Nuclear Engineering and Technology
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    • v.51 no.3
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    • pp.665-675
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    • 2019
  • The wire-wrapped fuel bundle is an assembly design in a sodium-cooled fast reactor. A wire spacer is used to maintain a constant gap between rods and to enhance the mixing of coolants. The wire makes the flow complicated by creating a sweeping flow and vortex flow. The vortex affects the flow field and heat transfer inside the subchannels. However, studies on vortices in this geometry are limited. The purpose of this research is to investigate the vortex flow created in the wire-wrapped fuel bundle. For analysis, a RANS-based numerical analysis was conducted for a 37-pin geometry. The sensitivity study shows that simulation with the shear stress transport model is appropriate. For the case of Re of 37,100, the mechanisms of onset, periodicity, and rotational direction were analyzed. The vortex structures were reconstructed in a three-dimensional space. Vortices were periodically created in the interior subchannel three times for one wire rotation. In the edge subchannel, the largest vortex occurred. This large vortex structure blocked the swirl flow in the peripheral region. The small vortex formed in the corner subchannel was negligible. The results can help in understanding the flow field inside subchannels with sweeping flow and vortex structures.

Traf4 is required for tight junction complex during mouse blastocyst formation

  • Lee, Jian;Choi, Inchul
    • Journal of Animal Reproduction and Biotechnology
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    • v.36 no.4
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    • pp.307-313
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    • 2021
  • Traf4 (Tumor necrosis factor Receptor Associated Factor 4) is a member of the tumor necrosis factor receptor (TNFR) - associated factors (TRAFs) family. TRAF4 is overexpressed in tumor cells such as breast cancer and associated with cytoskeleton and membrane fraction. Interestingly, TRAF4 was localized with tight junctions (TJs) proteins including OCLN and TJP1 in mammary epithelial cells. However, the expression patterns and biological function of Traf4 were not examined in preimplantation mouse embryos although Traf4-deficient mouse showed embryonic lethality or various dramatic malformation. In this study, we examined the temporal and spatial expression patterns of mouse Traf4 during preimplantation development by qRT-PCR and immunostaining, and its biological function by using siRNA injection. We found upregulation of Traf4 from the 8-cell stage onwards and apical region of cell - cell contact sites at morula and blastocyst embryos. Moreover, Traf4 knockdown led to defective TJs without alteration of genes associated with TJ assembly but elevated p21 expression at the KD morula. Taken together, Traf4 is required for TJs assembly and cell proliferation during morula to blastocyst transition.

Text Network Analysis of Korean Trade Stakeholder's Interactions - A Focus on the Trade Ministry and the Legislature (통상 이해관계자 간 상호작용 관련 텍스트 네트워크 분석(TNA) - 한국 통상부처와 입법부 관계를 중심으로)

  • Bomin Ko
    • Korea Trade Review
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    • v.45 no.6
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    • pp.23-43
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    • 2020
  • This study aims at analyzing the interactions between two of the most significant trade stakeholders in Korea, the Trade Ministry and the Legislature, using text network analysis. Tackling seven Action and Plan Reports for Requests from Parliamentary Inspection released by the National Assembly, this paper conducts a topic modelling analysis, particularly focusing on the reports for the three trade-related institutes: the MOTIE headquarter, Korea Trade Insurance Corporation, Korea Trade and Investment Promotion Agency. According to the analysis, such traditional topics of the MOTIE as enterprise, industry, business, management, development were frequently appeared in the reports. Trade-related topics including export, trade, commerce, investment, overseas, domestic, dispute, cooperation, efficiency, negotiation, service, promotion were repeatedly shown. Lastly, a case study on 2019 Parliamentary Inspection Report showed specific trade-related topics and relevant contents that raised issues in that year. This analysis implies that the text data driven from the Parliamentary Inspection Reports between the MOTIE and the National Assembly, can be established as so called 'trade policy information system' which are valuable not only for the two but also the rest of the trade stakeholders in Korea.

Uncertainty analysis of UAM TMI-1 benchmark by STREAM/RAST-K

  • Jaerim Jang;Yunki Jo;Deokjung Lee
    • Nuclear Engineering and Technology
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    • v.56 no.5
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    • pp.1562-1573
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    • 2024
  • This study rigorously examined uncertainty in the TMI-1 benchmark within the Uncertainty Analysis in Modeling (UAM) benchmark suite using the STREAM/RAST-K two-step method. It presents two pivotal advancements in computational techniques: (1) Development of an uncertainty quantification (UQ) module and a specialized library for the pin-based pointwise energy slowing-down method (PSM), and (2) Application of Principal Component Analysis (PCA) for UQ. To evaluate the new computational framework, we conducted verification tests using SCALE 6.2.2. Results demonstrated that STREAM's performance closely matched SCALE 6.2.2, with a negligible uncertainty discrepancy of ±0.0078% in TMI-1 pin cell calculations. To assess the reliability of the PSM covariance library, we performed verification tests, comparing calculations with Calvik's two-term rational approximation (EQ 2-term) covariance library. These calculations included both pin-based and fuel assembly (FA-wise) computations, encompassing hot zero-power and hot full-power operational conditions. The uncertainties calculated using both the EQ 2-term and PSM resonance treatments were consistent, showing a deviation within ±0.054%. Additionally, the data compression process yielded compression ratios of 88.210% and 92.926% for on-the-fly and data-saving approaches, respectively, in TMI fuel assembly calculations. In summary, this study provides a comprehensive explanation of the PCA process used for UQ calculations and offers valuable insights into the robustness and reliability of newly developed computational methods, supported by rigorous verification tests.

Thermal-hydraulic modeling of CAREM-25 advanced small modular reactor using the porous media approach and COBRA-EN modified code

  • Saeed Zare Ganjaroodi;Maryam Fani;Ehsan Zarifi;Salaheddine Bentridi
    • Nuclear Engineering and Technology
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    • v.56 no.5
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    • pp.1574-1583
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    • 2024
  • Small Modular Reactors (SMRs) are compact nuclear reactors designed to generate electric power up to 300 MWe. They could be assembled in factory, and then transported to be directly installed on-stie. CAREM (Central Argentina de Elementos Modulares) is a national SMR development project, based on light water reactor technology supervised by Argentina's National Atomic Energy Commission (CNEA). It is a natural circulation-based SMR with an indirect-cycle, including specific items and parts that simplify the design and improve safety performance. In this paper, the thermal-hydraulic study of CAREM-25 advanced small modular reactor is conducted by using COBRA-EN modified code and the Porous Media Approach (PMA) for the first time. According to PMA approach, each fuel assembly is modeled and divided into a network of lumped regions. While complex geometries are defined, the thermal-hydraulic parameters such as temperature and density are calculated for coolant and fuel rods. The obtained results show that the temperature in the fuel center may reach a peak around 1280 K in the hottest fuel assembly. Finally, the comparison of results from both methods (modified COBRA-EN and PMA) presented an appropriate consistency.