• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.3
• /
• pp.454-466
• /
• 2017

North Korea intended to increase the power of its nuclear weapons and standardize warhead to be loaded in ballistic missiles through the $4^{th}$ and $5^{th}$ nuclear tests. In this study, three kinds of nuclear weapons that North Korea might have used in the $4^{th}$ and $5^{th}$ nuclear tests to achieve their technical goals were suggested. Monte Carlo modeling and various technical assessments have shown that boosted fission weapons are most likely to be used. Also, using the empirical formula considering the burial depth of explosion, we found that the yield of the $4^{th}$ and $5^{th}$ nuclear tests is at least twice as strong as that is expected it could be and the initial design power could reach 8kt before amplification. This means that North Korea has already achieved a substantial level of nuclear fusion technology through the $4^{th}$ test and has made a breakthrough in the miniaturization of nuclear weapons through the $5^{th}$ test. After two or three additional tests, North Korea is expected to have nuclear missiles equipped with nuclear warhead by 2020, which is expected to complete ballistic missile development.

• Animal cells and systems
• /
• v.1 no.3
• /
• pp.491-496
• /
• 1997

When olfactory placodes are transplanted at stages 23/24 from Xenopus laevis to Xenopus borealis hosts of the same age, it is possible to distinguish the cell populations of the host and donor due to the peculiar nuclear Q bands specific to X. borealis. I have replaced the eye anlage in each of a number of X. borealis with the transplanted olfactory placode of an individual X. laevis, or vice versa. In most instances, the placode of the donor fuses with that of the host. When fusion occurs, but not when the host and donor orqans grow separately, the cells of the donor were replaced gradually and according to a characteristic pattern by cells of the host. The basal cells of the donor were the first to be replaced, followed by the more matured cells of the sensory epithelium. This cellular substitution, proceeding in an orderly fashion from bottom to upper layers of the epithelium, depends on the fusion of the two organs. This observation suggests intercellular contacts in the mitotic zone of the two organs favor the host's cells over those of the donor.

• Journal of the Korean Vacuum Society
• /
• v.15 no.1
• /
• pp.14-23
• /
• 2006

The scroll pump is widely used in ultra clean vacuum systems. However, there is no commonly available information on the hydrogen pumping characteristics of this pump, which creates a difficulty in determining whether the scroll pump can be used or not in a fusion experiment system where hydrogen ,is the main working gas. In this paper the experimental setup, measurement procedures, experimental results, and discussions on the pumping speed, the maximum compression ratio and the back-streaming properties of the scroll pump, especially for the hydrogen gas, are reported.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.5
• /
• pp.791-794
• /
• 2006

Cyclosophoraose (cyclic $\beta-(1,2)-glucan$, Cys) isolated from Rhizobium meliloti, a soil microorganism, was used as a solubility enhancer for flavonoids. The complexes of the cyclic oligosaccharide with flavonoids were confirmed through $^1H$ nuclear magnetic resonance (NMR) spectroscopic analysis. Flavonoids solubilized by Cys were quantitatively analyzed through high-performance liquid chromatography (HPLC). Among the flavonoids tested, the solubility of naringenin was greatly enhanced by Cys, compared with other compounds. The solubility of naringenin was enhanced about 7.1-fold by adding 10 mM Cys, compared with a control. $^1H$ NMR spectroscopic analysis indicated that the H-6 and H-8 protons, which are located on the A ring of naringenin, were greatly shifted upfield upon the complexation with Cys. This result suggested that Cys showed a regioselective interaction with the naringenin molecule upon the complexation, resulting in the solubility enhancement of naringenin.

• KIEE International Transactions on Power Engineering
• /
• v.3A no.2
• /
• pp.100-108
• /
• 2003

This paper presents the design and performance results of a pair of 6-kA high-temperature superconducting (HTS)-copper current leads, in which, over a short length at the warm end (e.g.,77K) of each HTS section, comprised of paralleled Bi-2223/Ag-Au tapes, is operated in the current-sharing mode. Because of their reliance on vapor cooling, the leads are applicable only to liquid helium cooled superconducting magnets such as those used in high-energy Physics accelerators and fusion machines. The experimental measurements have demonstrated that key performance data of the new 6-kA HTS-Copper leads agree reasonably well with those expected from design.

• Journal of Embryo Transfer
• /
• v.9 no.1
• /
• pp.31-41
• /
• 1994

핵 이식 기술을 이용한 cloning 송아지 생산이 처음 보고(Prather et al., 1987) 된 후, 소 수정란 Cloning에 대한 많은 연구가 분자 생물학 등 여러 분야에서 꾸준히 계속되고 있다. 이 기술은 빈우의 번식 능력을 향상시켜 유전적 개량량을 증대할 수 있는 번식과 육종을 위한 도구로써 많은 잠재력을 지니고 있다. 최근 핵 이식 기술을 이용하여 유전적으로 우수한 빈우로부터 수천개의 수정란을 생산하여, 이들 수정란에게 생산된 송아지가 번식 축군으로 공시되어 있으므로, 그 결과가 주목되나 아직까지는 비용이 많이 들고 송아지 생산 효율이 저조하므로, 가까운 장래에 일반 양축가에 이용될 가능성이 낮다. 그러나 이 기술의 실용화를 위하여 선결되어야 할 많은 문제점들 중, 지난 몇 년 동안 많은 연구기관에서 수행된 활발한 연구의 결실로써, 난포란 제핵, cell fusion 과 oocyte activation의 방법등 주요 장애 요인들이 점차 극복되면서 실용화를 위한 접근이 예견되어지며, 구미의 일부 개량 기관에서는 이를 상업화 하기 위한 여건을 다지고 있다. 그러므로 이 Review에서는 fllicular dynamics, 난포란의 성숙, cell cycle, 난포란 제핵, cell fusion과 oocyte activation, 이식후 핵의 remodeling과 reprogramming에 대한 현재까지의 보고된 자료를 기초로 그 기본 원리를 재고하는데 초점을 맞추었다.

• Journal of Korean Society for Quality Management
• /
• v.26 no.1
• /
• pp.201-212
• /
• 1998

A methodology of the safety analysis on the fusion power plant is introduced. It starts with the understanding of the physics and engineering of the plant followed by the assessment of the tritium inventory and flow rate. We a, pp.y the probabilistic risk assessment. An event tree that explains the propagation of the accident is constructed and then it is translated in to an influence diagram, that is accident is constructed and then it is translated in to an influence diagram, that is statistically equivalent so far as the parameter updating is concerned. We follow the Bayesian a, pp.oach where model parameters are treated as random variables. We briefly discuss the parameter updating scheme, and finally develop the methodology to obtain the predictive distribution of time to next severe accident.

• Journal of the Korean Ceramic Society
• /
• v.42 no.8 s.279
• /
• pp.575-581
• /
• 2005

SiC-based ceramics are considered as candidate materials for the advanced nuclear energy systems such as the generation IV reactors and the fusion reactors due to their excellent high-temperature strength and irradiation resistance. The advanced nuclear energy systems and their main components adopting ceramic composites were briefly reviewed. A novel fabrication method of $SiC_f/SiC$ composites by introducing SiC whiskers was also described. In addition, the charged-particle irradiation ($Si^{2+}$ and $H^{+}$ ion) into CVD SiC was carried out to simulate the severe environments of the advanced nuclear reactors. SiC whiskers grown in the fiber preform increased the matrix infiltration rate by more than $60\%$ compared to the conventional CVI process. The highly crystalline and pure SiC showed little degradation in hardness and elastic modulus up to a damage level of 10 dpa at $1000^{\circ}C$.

• Reproductive and Developmental Biology
• /
• v.28 no.4
• /
• pp.241-245
• /
• 2004

This study was conducted to investigate nuclear remodeling and developmental rate following nuclear transfer of fetal fibroblast cells, ear skin cells and oviduct epithelial cells into porcine recipient oocytes. To test par-thenogenetic activation, oocytes were treated with a 6-dimethylaminopurine (6-DMAP), a single DC-pulse (DC), calcium ionomycin (ionomycin), DC+6-DMAP and ionomycin + 6-DMAP after in vitro maturation. For nuclear transfer, in vitro matured oocytes were enucleated, and donor cells were transferred into oocytes. Cloned embryos were fused and stimulated with 6-DMAP for 4 h and cultured in vitro for 6 days. Among treatments for parthenogenesis, the activation rate of DC +6-DMAP treatment was significantly higher than that of single treatment roups (p<0.01), except for DC treatment group. However, the difference was not significant in activation rate compared to other complex treatment groups. Nuclear swelling of the cloned embryos was initiated at 60 min after stimulation and increased afterwards. Fusion rates were not different among different donor cells. Cleavage rates of DC treatment groups were significantly higher than those of DC+6-DMAP treatment groups (p<0.05) in case that fetal fibroblast and ear cells were used for nuclear donor. The cloned embryos from developed to blastocysts in oviduct epithelial cell nuclear transfer with DC+6-DMAP treatment was significantly higher compared to those with DC only treatment (p<0.05). However, no blastocyst was developed from nuclear transfer of fetal fibroblast and ear cells regardless of activation treatments. Based on these results, a proper activation stimulation may be necessary to increase the activation rate and the development to blastocyst in cloned porcine embryos.

• Reproductive and Developmental Biology
• /
• v.28 no.1
• /
• pp.13-20
• /
• 2004

This study was conducted to investigate the developmental ability of caprine embryos after somatic cell interspecies nuclear transfer. Donor cells were obtained from an ear-skin biopsy of a caprine, digested with 0.25% trypsin-EDTA in PBS, and primary fibroblast cultures were established in TCM-199 with 10% FBS. After maturation, expanded cumulus cells were removed by vigorous pipetting in the presence of 0.3% hyaluronidase. The matured oocytes were dipped in D-PBS plus 10% FBS＋7.5 $\mu\textrm{g}$/ml cytochalasin B and 0.05 M sucrose. The reconstructed oocytes were electrically fused with donor cells in 0.3 M mannitol fusion medium. After the electofusion, embryos were activated by electric stimulation. Interspecies nuclear transfer embryos with bovine cytoplasts were cultured in TCM-199 medium supplemented with 10% FBS including bovine oviduct epithelial cells for 7∼9 day. On the other hand, the NT embryos with porcine cytoplasts were cultured in NCSU-23 medium supplemented with 10% FBS for 6∼8 day at $39^{\circ}C, 5% CO_2$ in air. In caprine-bovine NT embryos, the cleavage(2-cell) rate was 36.8% in confluence and 43.8% in serum starvation. The developmental rate of morula- and blastocyst-stage embryos was 0.0% in confluence and 18.8% in serum starvation. In caprine-porcine NT embryos, the cleavage(2-cell) rate was 76.7% in confluence and 66.7% in serum starvation. The developmental rate of morula and blastocyst stage embryos was 3.3% in confluence and 3.0% in serum starvation, and no significant difference was observed in synchronization treatment between donor cells. In caprine-bovine NT embryos, the cleavage(2-cell) rate of cultured donor cells was 30.8% and 17.6% in 5∼9 and 10∼14 passage(P＜0.05). The developmental rate of morula and blastocyst stage embryos were significantly higher(P＜0.05) in 5∼9 passage(23.1%) than in 10∼14 passage(0.0%) of cultured donor cells. In caprine-porcine NT embryos, the cleavage rate was significantly higher(P＜0.05) in 5∼9 passage(86.7%) than in 10∼14 passage(50.0%) of cultured donor cells. The developmental rate of morula and blastocyst stage embryos were 3.3 and 0.0% in 5∼9 and 10∼14와 passage of cultured donor cells. In caprine-bovine NT embryos, the developmental rate of morula and blastocyst stage embryos were 22.6% in interspecies nuclear transfer, 33.9% in in vitro fertilization and 28.1% in parthenotes, which was no significant differed. The developmental rate of morula and blastocyst stage embryos with caprine-porcine NT embryos were lower(P＜0.05) in interspecies nuclear transfer(5.1%) than in vitro fertiltzation(26.9%) and parthenotes(37.4%).