• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1860-1865
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• 2019

The confinement degradation of the energetic particles during RMP would be a key issue in success of realizing the successful energy production using fusion plasma, because a 3.5 MeV energetic alpha particle should be able to sustain the burning plasma after the ignition. As KSTAR recent results indicate the generation of high-performance plasma(${\beta}_p{\sim}3$), the confinement of the energetic particles is also an important key aspect in neutral beam driven plasma. In general, the measured absolute value of the neutron intensity is generally used for to estimating the confinement time of energetic particles by comparing it with the theoretical value based on transport calculations. However, the availability of, but for its calculation process, many accurate diagnostic data of plasma parameters such as thermal and incident fast ion density, are essential to the calculation process. In this paper, the time evolution of the neutron signal from an He3 counter during the beam blank has permitted to facilitate the estimation of the slowing down time of energetic particles and the method is applied to investigate the fast ion effect on ELM suppressed KSTAR plasma which is heated by high energy deuterium neutral beams.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3703-3716
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• 2022

Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments' results, thereby improving the success rate of the experiments.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.291-291
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• 2004

Micromanipulation and fusion are essential to generate nuclear transfer embryos. In this process cytoplasmic damage is unavoidable. This study investigated the hypothesis that higher osmolarity than normal culture medium could help oocytes recover from cytoplasmic damage from micromanipulation and electric pulse. Oocytes derived from a local slaughter house were matured for 42 ∼ 44 h and enucleated. (omitted)

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.867-868
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• 2004

The maximum width of HAZ of SA508치.3 steel produced by overlay RPV cladding was approximately 10 mm and it was composed of variety of microstructures with various grain size and precipitates. In addition, along the weld fusion line there formed a heavy carbide precipitation zone in the width of $20{\sim}30\;{\mu}m$. 2. As the specimen sampling position approached to the weld fusion line, the increase in yield and tensile strength was approximately 90 and 40 MPa, respectively. Meanwhile, the plastic fracture strain reduced from 14 to 8 percent. 3. The lowest SP energy and the highest ductile to brittle transition temperature in the HAZ were observed at the coarse- and fine-grained HAZ.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1346-1353
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• 2017

The FISPACT-II inventory simulation platform is a modern computational tool with advanced and unique capabilities. It is sufficiently flexible and efficient to make it an ideal basis around which to perform extensive simulation studies to scope a variety of responses of many materials (elements) to several different neutron irradiation scenarios. This paper briefly presents the typical outputs from these scoping studies, which have been used to compile a suite of nuclear physics materials handbooks, providing a useful and vital resource for material selection and design studies. Several different global responses are extracted from these reports, allowing for comparisons between materials and between different irradiation conditions. A new graphical output format has been developed for the FISPACT-II platform to display these "global summaries"; results for different elements are shown in a periodic table layout, allowing side-by-side comparisons. Several examples of such plots are presented and discussed.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.18-18
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• 2001

Despite of importance of integrated events of nucleus and microtubule remodeling in nuclear transferred embryos with somatic cells, little information is available on this subject. In this study we configured chromatin and microtubule organization following somatic cell nuclear transfer in pre- and non-activated bovine oocytes in order to clearify nuclear remodeling process and to demonstrate centrosome inheritance during nuclear transfer. The cumulus-oocyte complexes were collected from slaughterhouse and were matured in vitro for 20 h in TCM 199 supplemented hormone. Matured bovine oocytes were enucleated by aspirating the frist polar body and metaphase chromatin using a beveled pipette. Bovine fibroblast cells were fused into enucleated oocyte by electrical stimulation. Reconstructed oocytes were activated with ionomycine and 6-dimethylaminopurin, and then cultured in CRlaa medium. The organization of nuclear and microtubules were observed using laser-scanning confocal microscopy. At 1 hour after fusion, microtubule aster was seen near the transferred nucleus in most oocytes regardless activation condition. While most of fibroblast nuclei remodeled to premature chromosome condensation (PCC) and to the two masses of chromosome in non-activated oocytes, a few number of fibloblasts went to PCC and multiple pronuclear like structures in activated oocytes. Microtubular spindle was seen around condensed chromosome. Gamma-tubulin was detected in the vicinity of condensed chromosome, suggesting this is a transient spindle. The spindle seperated nucleus into two masses of chromatin which developed to the pronuclear like structures. Two pronuclear like structures were than apposed by microtubular aster and formed one syngamy like nuclear structure at 15 h following nuclear transfer. At 17 to 18 h after fusion, two centrosomes were seen near the nucleus, which nucleates micrtubules for two cell cleavage. While 31% of reconstructed oocytes in non-activated condition developed to morulae and blastocysts, a few reconstructed oocytes in pre-activated condition developed to the blastocyst. These results suggested introduction of foreign centrosome during nuclear transfer, which appeared to give an important role for somatic cell nuclear reprogramming.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.93-98
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• 2006

Human foamy virus (HFV) integrase mediates integration of viral c-DNA into cellular DNA. In this process, HFV prointegration complex (PIC) in which integrase is a key component moves to nuclei of the infected cells and leads to integration of viral DNA to the cellular genome, which is essential in viral life cycle. In general nuclear localization signals (NLS) have been suggested to be involved in localizing retroviral PIC to nuclei, but the mechanisms for nuclear localization of the HFV PIC remains unclear. To functionally identify the NLS of HFV integrase, various subdomains of the protein were expressed as GFP fusions and their subcellular locations were analyzed with confocal laser scanning microscopy. Wild type HFV integrase was karyophilic by targeting the fusion protein to nuclei of the COS-1 and 293T cells. Our results showed that strong NLS of HFV integrase was mapped to the C-terminal regions. In addition the karyophilic properties of N-terminal and central regions are not individually strong enough to direct localization of the fusion proteins to nuclei, but their cooperative activity for nuclear import was confirmed.

• Carbon letters
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• v.4 no.1
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• pp.36-39
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• 2003

Carbon and carbon-based materials are used in nuclear reactors and there has recently been growing interest to develop graphite and carbon based materials for high temperature nuclear and fusion reactors. Efforts are underway to develop high density carbon materials as well as amorphous isotropic carbon for the application in thermal reactors. There has been research on coated nuclear fuel for high temperature reactor and research and development on coated fuels are now focused on fuel particles with high endurance during normal lifetime of the reactor. Since graphite as a moderator as well as structural material in high temperature reactors is one of the most favored choices, it is now felt to develop high density isotropic graphite with suitable coating for safe application of carbon based materials even in oxidizing or water vapor environment. Carboncarbon composite materials compared to conventional graphite materials are now being looked into as the promising materials for the fusion reactor due their ability to have high thermal conductivity and high thermal shock resistance. This paper deals with the application of carbon materials on various nuclear reactors related issues and addresses the current need for focused research on novel carbon materials for future new generation nuclear reactors.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.171-178
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• 2003

This study was conducted to investigate the effect of electric fusion methods on cell fusion rate and embryo development by somatic cell nuclear transfer in Korean Native Cattle. The KNC ear cell was cultured in vitro for confluence in serum starvation condition(DMEM＋0.05％ FBS) for cell confluence. The zona pellucida of IVM oocytes were partially dissection using micro pipette. Ear cells were transferred into an enucleated oocyte. The reconstructed embryos were electrically fused with Zimmermann Cell Fusion Medium(ZCFM). Nuclear transfer embryos were activated with a combination of 10${\mu}{\textrm}{m}$ calcium ionophore(5 min) and 2.0mM 6-DMAP(3 hr). The activated embryos were cultured in CR1 -aa medium contains 0.3％ BSA or 10％ FBS at 37$^{\circ}C$, 90％ $N_2$, and 5％ $CO_2$in incubator for 6 days. The fusion rates were 51.6％(chamber) and 68.9％(needle), respectively and there were significantly difference between the fusion method(P<0.05). But, lysis rates were not significantly different(10.7％, 11.5％), respectively. The cleavage rates were significantly different between the chamber method(73.2％) and needle method(80.3％), respectively(P<0.05). The rates of early embryos(2∼4cells) and blastocysts of chamber and needle methods were 54.1％, 61.1％ and 18.4％, 26.3％ respectively, and needle method was significantly higher than chamber method(P<0.05). But, morulae formation rate were not significantly differences between the chamber(6.7％) and needle(6.2) method(P <0.05). These result suggest that electric fusion of needle method was to be profitable for nuclear transfer embryo fusion rate, blastocyst formation rate and reduce of oocyte lysis.

• Applied Microscopy
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• v.13 no.1
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• pp.31-40
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• 1983

Ultrathin sections of intact mycelia, released protoplast and fused protoplast of Micromonospora rosaria were observed by electron microscopy Intact mycelia showed a typical gram-positive bacterial cell wall structure and mesosomes. Released protoplasts had no cell wall components and fibrous nuclear region was distinguished from cytoplsmic region clearly. Protoplasts which treated with sucrose supplemented buffer were stable. But those treated with buffer without sucrose were extensively damaged, forming mom braneous vesicles. It was surmised that those vesicles originated from the damaged cytoplasmic membrane. High frequency of fusion was achieved by 50%(w/v). polyethylene-glycol 1,000 Fusion bodies in different stage of fusion were observed. Cell membrane barrier was stepwise relieved.