• Nuclear Engineering and Technology
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• 제47권3호
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• pp.380-387
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• 2015

A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as $^{235}U$, $^{239}Pu$, $^{241}Pu$, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux ($>10^{12}n/cm^2{\cdot}s$) neutron source comprised of a high-energy (30 MeV)/high-current (~2 A) electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (< $0.06{\mu}Sv/h$), a few shielding materials [high-density polyethylene (HDPE)eBorax, $B_4C$, and $Li_2CO_3$] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in the near future.

• Asian-Australasian Journal of Animal Sciences
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• 제23권7호
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• pp.946-951
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• 2010

The objective of this research was to evaluate the effects of dietary supplementation of blood meal (BM) as a source of histidine, and magnesium oxide (MgO) as a catalyst of carnosine synthetase, on carnosine (L-Car) content in the chicken breast muscle (CBM), laying performance, and egg quality of spent old hens. Four hundred eighty laying hens (Hy-Line$^{(R)}$ Brown), 95wk old, were allotted randomly into five replicates of six dietary treatments: T1; 100% basal diet, T2; 100% basal diet+MgO, T3; 97.5% basal diet+2.5% BM, T4; 97.5% basal diet+2.5% BM+MgO, T5; 95% basal diet+5% BM, T6; 95% basal diet+5% BM+MgO. Magnesium oxide was added at 0.3% of diets. The layers were fed experimental diets for 5wk. There were no significant differences in the weekly L-Car content in CBM among all treatments during the total experimental period, but some of the contrast comparisions showed higher L-Car in CBM of T6. The L-Car contents linearly decreased (p<0.01 or p<0.05) as the layers got older except in T4 (p>0.05). There were significant differences in egg weight (p<0.01) and soft and broken egg ratio (p<0.05). The control (T1) was highest in egg weight and T6 was lowest in soft and broken egg ratio. Among the parameters of egg quality, there were significant differences in eggshell strength (p<0.01) and egg yolk color (p<0.05). Magnesium oxide supplementation increased the eggshell strength and BM tended to decrease egg yolk color. Eggshell color, eggshell thickness, and Haugh unit were not influenced by BM and MgO. In conclusion, BM and MgO did not significantly influence the L-Car in CBM of spent layers. The L-Car content rapidly decreased as the layers became senescent. Eggshell strength was increased by MgO supplementation.

• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.247-254
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• 2016

Cytological changes of the epithelial cells according to the developmenatal phases of the seminal vesicle related to the spermatogenic stages in the testicular lobules during spermagenesis in male Neptunea (Barbitonia) cumingii (Gastropoda: Buccinidae) were investigated monthly by electron microscopical and histological observations. N. (B) cumingii is dioecious, and an internal fertilization species. The male genital organ is located near the tentacles. The spermatozoon is approximatley $50{\mu}m$ in length. The axoneme of the tail flagellum consists of nine pairs of microtubles at the periphery and one pair at the center. The process of germ cell development during spermatogenesis can be divided into five succesive stages: (1) spermatogonia, (2) primary spermatocytes, (3) secondary spermatocytes, (4) spermatids, and (5) spermatozoa. A considerable amount of spermatozoa make their appearance in the testicular lobules (or acini) and some of them are tranported from the testis towards the seminal vesicles until late July. In this study, the developmental phases of the epithelial cells of the seminal vesicles of N. (B.) cumingii could be classified into four phases: (1) S-I phase (resting), (2) S-IIphase (early accumulating), (3) S-III phase (accumulating), and (4) S-IV phase (spent). However, in case of N. (B.) arthritica cumingii, the developmental phases of the seminal vesicle were devided into three phases: (1) resting, (2) accumulating and (3) spent. Granular bodies in the inner layer of the seminal vesicles are involved in resorption of digestion of residual spermatozoa.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.5-10
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• 2005

We deal with the sliding mode control using the time delay estimation. The time delay estimation is able to weaken the need for obtaining a quantitative plant model analogous to the real plant so the sliding mode control with a time delay estimation (SMCTE) is very suitable for plant such as SMA actuators whose quantitative model is difficult to obtain. We have already studied the application of the time delay control (TDC) to SMA actuators in other literature. Based on the previous study on the TDC, we developed the gain tuning method for the SMCTE, which results were nearly the same as the TDC. With respect to the step response, the SMCTE proved its predominance in a comparison with other control schemes such as the PID control and the relay control. As well as the contribution of the above control methodology, the model identification for SMA actuators has also been studied. The dynamics for an SMA actuator was newly derived using the modified Liang's model. The derived dynamics showed a continuity at the change of the phase transformation process but the original Liang's model could not.

• Corrosion Science and Technology
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• 제19권1호
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• pp.1-7
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• 2020

Chalk River Unidentified Deposits (CRUDs) were collected from the Korean pressurized water reactor (PWR) plant (A, B, and C) where the axial offset anomaly (AOA) occurred. AOA, also known as a CRUD-induced power shift, is one of the key issues in maintaining stable PWR plant operations. CRUDs were sampled from spent nuclear fuel rods and analyzed using an electron probe micro-analyzer (EPMA). This paper describes the characteristics of boron-deposits from the CRUDs sampled from twice-burnt assemblies from the Korean PWR. The primary coolant of a PWR contains boron and lithium. It is known that boron deposition occurs in a thick CRUD layer under substantial sub-cooled nucleate boiling (SNB). The results of this study are summarized as follows. Boron was not found at the locations where the existence was confirmed in simulated CRUDs, in other words, the cladding and CRUD boundaries. Nevertheless, we clearly observed the presence of boron and confirmed that boron existed as a lump in crystalline form. In addition, the study confirmed that CRUD existed in a crystal form with a unique size of about 10 ㎛.

• 한국재료학회지
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• 제14권4호
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• pp.251-259
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• 2004

In the development of the advanced spent fuel management process based on the molten salt technology, it is essential to choose the optimum material for the process equipment handling molten salt. Corrosion behavior of Ni 200 and Ni-base alloys in molten salt of LiCl-$Li_2$O under oxidation atmosphere was investigated in the temperature range of $650～800^{\circ}C$ for 24～312 hrs. The order of corrosion rate was Ni 200 > Inconel 690 > Inconel 601 > Inconel 600. Inconel 600 alloy showed the highest corrosion resistance among the examined alloys, but Ni 200 exhibited the highest corrosion rate. Corrosion products of Inconel 600 and Inconel 601 were $Cr_2$$O_3$ and $NiFe_2$$O_4$. In case of Inconel 690, a single layer of $CrO_2$$O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2$O$_4$ and inner layer of $Cr_2$$O_3$ were formed with increase of corrosion time. Inconel 600 showed local corrosion behavior and Inconel 601, 690 showed uniform corrosion behavior.

• 한국가금학회지
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• 제38권3호
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• pp.197-204
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• 2011

본 연구는 기능성 물질인 누에고치 분말, 동충하초 분말과 CLA의 단독 혹은 혼합 첨가가 산란 노계 가슴살에서 회수한 단백질을 이용하여 명태 연육을 20% 대체한 크래미의 저장 중 이화학적 및 조직학적 특성을 분석한 결과이다. pH 및 백색도를 나타내는 W는 누에고치 및 동충하초 분말을 함께 첨가한 T2에서 유의적으로 높게 나타난 반면, 전단력은 T2가 가장 낮았다(p<0.05). 명도를 나타내는 $L^*$과 탄력성에서는 누에고치 분말을 첨가한 T1이 가장 높았으며, 적색도를 나타내는 $a^*$, 황색도를 나타내는 $b^*$ 및 파괴 강도에서는 T1이 다른 처리구에 비해 유의적으로 낮았다(p<0.05). 표면경도와 부착성에서는 동충하초 분말과 CLA를 함께 첨가한 T3에서 유의적으로 높게 나타났으며, 파괴 강도 및 겔 강도에서는 T2와 T3가 높았다(p<0.05). 따라서 본 실험은 산란 노계 가슴살 회수단백질을 이용하여 명태 연육을 대체하며 제조한 크래미에 누에고치 분말과 동충하초 분말을 함께 첨가하며 생산한다면 크래미의 품질 특성 평가에 있어 중요한 항목으로 구분되는 백색도와 겔 강도를 향상시키고, 전단력을 감소시켜 안정적인 조직과 높은 연도를 가진 제품의 생산이 가능할 것으로 판단된다. 이와 더불어 누에고치와 동충하초가 가진 항암과 항산화 효과 및 뇌 기능의 활성화 등 다양한 생리 활성 효과를 함유한 기능성 크래미를 제조 판매 할 수 있어 소비자의 구매 욕구를 충족시킬 수 있을 것으로 판단된다.

• 한국가금학회지
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• 제21권4호
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• pp.239-247
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• 1994

A study was conducted to investigate the effects of the addition of varied levels of NaCi and phosphates on the physicochernical properties of the breast meat of the spent layers(2 \pm 0.2 kg) which were stabilized for over 24 h before slaughter. Within 1 h after slaughter, breast meats were removed and treated with NaGl(0, 1, 2, 3%) and phosphates(0.25% and 0.5%) using a hot-salted method. The breast meat was stored at 4 \pm $1^{\circ}C$ for 3 d. The results obtained were summarized as follows. 1. The pH values of salt-treated groups were significantly higher than that of the control(P<0.05) ; the higher the salt level, the higher the pH. The pH values were significantly increased in both control and treatment groups during storage(P<0.05). Among salt-treated groups, the 0.5% phosphates level showed significantly high pH(P<0.05) compared to other levels of salt groups. 2. The moisture contents were significantly lower in all salt4reated groups than the control(P<0.05), and showed a negative relationship with the levels of salt. It decreased in control group gradually as the storage period extended, but not significantly changed in salt-treated groups. 3. The shear force values in salt-treated groups were lower than that of the control and showed a negative relationship with salt levels. At a constant level of NaCI, the shear force value was higher in 0.25% phosphates level than in 0.5% level. It decreased in both control and salt-treated groups during storage. 4. The salt treatments tended to increase the sodium content proportionately. The sodium content decreased in both control and salt treatment groups during storage(P<0.05). In addition, the combination of high levels of NaCl and phosphates rather than those of low levels of NaCI and phosphates resulted in elevated levels of sodium. 5. The phosphorus contents in salt-treated groups were higher than that of control. Between 0.5% and 0.25% phosphates levels this value showed significant difference(P<0.05). Its contents in both control and treatment groups were significantly decreased during storage (P<0.05).

• 한국축산식품학회지
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• 제33권2호
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• pp.251-257
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• 2013

수리미에 대한 노계 분쇄 가슴육으로의 대체가 저장 중 크래미의 품질에 미치는 영향을 조사하기 위하여 소시지 제조에 이용되는 커터를 활용하여 노계 가슴육을 분쇄하였으며, 이후 수리미를 노계 분쇄육으로 5(05CM)와 10%(10CM) 대체하며 크래미를 제조하였다. 크래미의 제조 후 모든 크래미는 $10{\pm}1^{\circ}C$에서 3주간 저장하며 실험하였다. 크래미의 수분함량은 두 처리구 모두에서 저장기간이 지남에 따라 유의적으로 감소하였으나, 대조구보다는 높은 수분함량을 나타내었다(p<0.05). 더욱이, 지방의 산화를 나타내는 TBARS는 분쇄육으로 수리미를 5%까지 대체한 05CM보다는 10%까지 대체한 10CM에서 더욱 감소하였다. 크래미 시료의 육색을 나타내는 CIE $b^*$와 $a^*$는 수리미를 5와 10%까지 분쇄육으로 대체한다면 황색도는 증가하나 적색도는 유의적으로 감소하였다(p<0.05). 크래미의 전 단가와 겔 특성 중 파괴강도와 젤리강도는 저장기간 보다는 분쇄육으로의 대체에 따라 유의적으로 감소하였으나 이러한 결과가 훈련된 관능검사 요원의 관능적 평가에는 영향을 미치지 않았다. 본 실험을 통하여 크래미 제조를 위한 수리미를 노계 분쇄 가슴육으로 10%까지 대체한다 하여도 수치적으로는 조직적인 특성에 영향을 미칠 수 있다 할 수 있겠으나 그 영향은 관능적 평가에 의해 유의적인 차이를 나타낼만한 것은 아니었다. 따라서 크래미 제조를 위한 수리미 10%의 노계 분쇄 가슴육 대체는 경제적인 측면에서도 고려 가능한 대체방법인 것으로 판단된다.