• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.203-204
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• 2002

The wear behaviour of steam generator (SG) tubes (Inconel 600 and 690) against support materials (405 and 409 ferritic stainless steels) has been experimentally studied in room temperature water using reciprocating wear apparatus with tube-an-plate configuration. The results showed that the wear rate of Inconel 690 was lower than that of lnconel 600 with increasing normal loads and sliding amplitudes. Also, plastic deformation layers appear below the surface of both SG tubes, which have a specific thickness and are small compared with their grain size. This means that wear rate of SG tubes in water condition is closely related to the formation and fracture of plastic deformation layers.

• Applied Microscopy
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• 제26권4호
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• pp.401-410
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• 1996

The microwave fixator has recently been introduced in morphological research. The present study was carried out to investigate the ultrastructural effects of microwave fixation of rat brain. kidney, liver and skeletal muscle tissues. The results are as follows: In the case of microwave fixed cerebrum. the cytoplasmic processes of neurons and the various membranous organelles such as nuclear envelope, mitochondria, rough endoplasmic reticulum and Golgi apparatus were well preserved, The myelin sheath wrapping neuronal axon was prominent. Microwave fixed hepatocytes showed the microvilli on the free surface of bile canaliculus, the evident nucleolar components, and typical organelles. In nephron, ultrastructures of glomerulus and Bowman's capsule were preserved, and also tubular wall were structurally observed. Among the skeletal muscle cells, plentiful collagen fibers were appeared, myofibrils and mitochondria were typically observed. In conclusion, the microwave fixation procedures result in an good preservation of the tissues and would be time- and reagent-saving.

• 한국안전학회지
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• 제14권3호
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• pp.3-11
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• 1999

The atomic fuel rods between top and bottom end pieces of reactor need to be extended for high combustion rate of future-type fuel to increase the irradiation in the axial direction. For allowing axial extension of the fuel rods, the space between top and bottom end pieces should be expanded. Thus the thickness reduction of the flow plate is necessary. This study was carried out the mechanical strength test by using strain gages as a function of flow plate thickness, the existence of skirt and loading condition for the Korean Fuel Assembly(KOFA). The experimental apparatus was designed for load conditions, uniformly distributed load and displacement. Test method using whiffle tree of uniformly distributed load has been comparatively conservative. The test results were compared with those of finite element analysis and the test method on bottom end piece was established.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.41-47
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• 1998

The solvent flushing apparatus for soil remediation was manufactured. After the soil around nuclear facilities was sampled and was compulsorily contaminated by Co, the remediation characteristics by solvent flushing were analyzed. Meanwhile, one-dimensional solute transport within nonequilibrium sorption code was developed for modelling of the soil remediation, input parameters for modelling were measured by laboratory experiment. Experimental results are as follows : When water was used as a solvent, the higher was the hydraulic conductivity, the higher the efficiency of soil remediation was. When EDTA solution was used as a solvent, the soil remediation efficiency of EDTA solution showed higher than that of water.

• Journal of Species Research
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• 제6권spc호
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• pp.1-7
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• 2017

Eight samples, collected from six moss-covered soil and two freshwater samples, were examined to determine ciliate diversity in Korea. Based on the morphology of living and stained specimens, thirteen ciliate species, previously unrecorded in Korea, were identified. These specimens were classified to four classes, seven orders, ten families, and twelve genera. Of these genera, the following six were first records in Korea: Bresslauides, Dexiotricha, Glaucoma, Paragastrostyla, Sathrophilus, and Trithigmostoma. Here, we provide a brief description of the morphology of these 13 taxa along with microphotographs and notes.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.163-166
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• 2001

KEPCO has a plan to construct TRF (tritium removal facility) in wolsong nuclear power plant site by 2005. In advance of WTRF construction, the pilot plant was installed at KEPRI in order to show process reliability of WTRF. The main processes of this pilot plant are LPCE(liquid phase catalytic exchange) and CD (cryogenic distillation). Deuterium is separated from heavy water in LPCE process and concentrated in CD process. CD process consists of cold box, where are a distillation column and heat exchangers, vacuum system, cryogenic refrigerant supply system and instrument & control system. The experience of the pilot plant will be used in WTRF design review, operating procedure revision and fundamental education for the operators.

• Journal of Welding and Joining
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• 제21권6호
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• pp.20-25
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• 2003

Various welding methods such as Gas Tungsten Arc Welding(GTAW), magnetic force electrical resistance welding and Laser Beam Welding(LBW) are now available for end cap closure of nuclear fuel rods. Even though the resistance and GTA welding processes are widely used in manufacturing commercial fuel rods, they can not be recommended for the remote seal welding of fuel rods in the hot cell Facility due to the complexity of the electrode alignment, the difficulty in replacing parts in a remote manner and the large heat input for the thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for the end cap welding of irradiation fuel rods in the hot cell. The remote laser welding apparatus in the hot cell Facility was developed using a pulsed Nd:YAG laser of 500 watt average power with an optical fiber transmission. The weldment quality such as microstructure and mechanical strength was satisfactory. The optimum conditions of laser welding for encapsulating irradiation fuel rods in the hot cell were obtained.

• 대한한의학회지
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• 제18권1호
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• pp.430-445
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• 1997

In order to know the effects of Calculus $Bovis{\cdot}F디$ Ursi aqua-acupuncture ($C{\cdot}F$ aqua-acupuncture) to the liver damage, we carried out the treatment of $C{\cdot}F$ aqua-acupuncture and injection of Kam-Du-Tang on the liver damaged rat which is induced by aconitine, and then ultrastructural study has been to the liver tissue. The results were as follows: 1. In the hepatic cell of normal group, the nuclear envelope is round and electro-density of nucleoplasm is relatively low, and have one or two large nucleolus. Cell organelle is developed rough endoplasmic reticulum(RER) and many mitochondria, glycogen granules, smooth endoplasmic reticulum(SER) and Golgi apparatus. 2. In 24 hours control group, nuclear envelope is very irregular, RER and most of cell organell is shown that destroyed by aconitine. This is similar to the 48 hours control group. In 72 hours control group, RER is recovered somewhat but cristae of mitochondria is not seen the shape 3.In 24 hours $C{\cdot}F$ aqua-acupuncture group, nuclear envelope is very irregular and cristernae is very dilatable and many mitochondria is dilationed and the cristae is not definite like the control group. In 48 hours $C{\cdot}F$ aqua-acupuncture group, nuclear envelope is relatively round and chromatin is regular. Cristernae of RER and ribosme is somewhat imperfect but is similar the normal group, and the cristae of mitchondria is shown definitely like the normal group. In 72 hours $C{\cdot}F$ aqua-acupuncture group, nuclear envelope is round and cell organell is similar to normal group. 4. In 24 hours Kam-Du-Tang group, nuclear envlope is very irregular and cell organelles are destroyed by the effects of aconitine. In 48 hours Kam-Du-Tang group, nuclear envelope is somewhat irregular but chromatin is relatively regular. RER is seperated regularly through the cytoplasm, but cannot make the structure of lamina, and cistennae is very dilationed. many of glycogen granules is seperated regularly. In 72 hours Kam-Du-Tang group, RER makes the lamina. Mitochondria is a little but inner space is dilationed so the shape of is not definite and a lot of glycogen granules are accumulated in several places. It see the above result, hepatic cell that is damaged by aconitine is effected chiefly by the $C{\cdot}F$ acupuncture and effect of acupuncture is similar to the detoxicated effect of Kam-Du-Tang.

• Clinical and Experimental Reproductive Medicine
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• 제50권3호
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• pp.177-184
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• 2023

Objective: Reconstructed oocytes after polar body genome transfer constitute a potential therapeutic option for patients with a history of embryo fragmentation and advanced maternal age. However, the rescue of genetic material from the first polar body (PB1) through introduction into the donor cytoplasm is not yet ready for clinical application. Methods: Eighty-five oocytes were obtained following in vitro maturation (IVM) and divided into two groups: PB1 nuclear transfer (PB1NT; n=54) and control (n=31). Following enucleation and PB1 genomic transfer, PB1 fusion was assessed. Subsequently, all fused oocytes underwent intracytoplasmic sperm injection (ICSI) and were cultured in an incubator under a time-lapse monitoring system to evaluate fertilization, embryonic morphokinetic parameters, and cleavage patterns. Results: Following enucleation and fusion, 77.14% of oocytes survived, and 92.59% of polar bodies (PBs) fused. However, the normal fertilization rate was lower in the PB1NT group than in the control group (56.41% vs. 92%, p=0.002). No significant differences were observed in embryo kinetics between the groups, but a significant difference was detected in embryo developmental arrest after the four-cell stage, along with abnormal cleavage division in the PB1NT group. This was followed by significant between-group differences in the implantation potential rate and euploidy status. Most embryos in the PB1NT group had at least one abnormal cleavage division (93.3%, p=0.001). Conclusion: Fresh PB1NT oocytes successfully produced normal zygotes following PB fusion and ICSI in IVM oocytes. However, this was accompanied by low efficiency in developing into cleavage embryos, along with an increase in abnormal cleavage patterns.

• 방사성폐기물학회지
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• 제1권1호
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• pp.47-53
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• 2003

한국원자력연구소에서는 산화물 형태의 사용후핵연료를 용융염 매질에서 금속으로 전환함으로써 사용후핵연료의 발열량, 부피 및 방사능을 1/4로 감소시킬 수 있는 전기화학적 금속전환공정을 개발하고 g 규모(3-40g $U_{3}O_{8}$ batch)로 기초실험을 수행하고 있다. 본 연구에서는 전기화학적 금속전환 장치를 5kg $U_{3}O_{8}$ batch 규모로 설계 제작하고, 목표로 하고 있는 20kg $U_{3}O_{8}$ batch 규모 핫셀 실증을 위한 장치설계자료를 산출하기 위해 mock-up test를 수행하였다. 운전변수에 따른 $U_{3}O_{8}$의 전기화학적 환원거동을 규명하였으며, $U_{3}O_{8}$ 분말을 99% 이상 금속전환하여 전기화학적 금속전환공정의 타당성을 kg 규모로 검증할 수 있었다.