• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1978-1982
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• 2019

The paper presents the electrical performance measurements of a prototype nuclear battery and two types of betavoltaic cells. The electrical performance was assessed by measuring current-voltage properties (I-V) and determining the short-circuit current and the open-circuit voltage. With ⁶³Ni as an irradiation source, the open-circuit voltage and the short-circuit current were determined as 1 V and 64 nA, respectively. The prototype consisted of 10 betavoltaic cells that were prepared using radioactive ⁶³Ni. Electroplating of the radioactive ⁶³Ni on an ohmic contact (Ti-Ni) was carried out at a current density of 20 mA/㎠. Two types of betavoltaic cells were studied: with an external ⁶³Ni source and a ⁶³Ni-covered source. Under irradiation of the ⁶³Ni source with an activity of 10 mCi, the open-circuit voltage V_oc of the fabricated cells reached 151 mV and 109 mV; the short-circuit current density J_sc was measured to be 72.9 nA/cm2 and 64.6 nA/㎠, respectively. The betavoltaic cells had the fill factor of 55% and 50%, respectively.

• 콘크리트학회논문집
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• 제25권2호
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• pp.225-232
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• 2013

최근 건설시장의 세계적인 흐름은 방법 및 수행 절차보다는 최종 성과물의 성능을 제시하는데 초점을 맞춘 성능중심 설계기준으로 변화하고 있는 실정이다. 또한, 콘크리트 재료 및 구조물의 성능 검증을 위하여 재령효과에 따른 콘크리트 강도를 검토할 경우 적절한 모델을 사용하여야 한다. 따라서 이 논문에서는 국내 재료 특성을 반영한 콘크리트 강도발현 상수를 제안하고, 그 적합성을 평가하였다.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.817-824
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• 2017

Residual stress is a critical element in determining the integrity of parts and the lifetime of welded structures. It is necessary to estimate the residual stress of a welding zone because residual stress is a major reason for the generation of primary water stress corrosion cracking in nuclear power plants. That is, it is necessary to estimate the distribution of the residual stress in welding of dissimilar metals under manifold welding conditions. In this study, a cascaded support vector regression (CSVR) model was presented to estimate the residual stress of a welding zone. The CSVR model was serially and consecutively structured in terms of SVR modules. Using numerical data obtained from finite element analysis by a subtractive clustering method, learning data that explained the characteristic behavior of the residual stress of a welding zone were selected to optimize the proposed model. The results suggest that the CSVR model yielded a better estimation performance when compared with a classic SVR model.

• Asian Pacific Journal of Cancer Prevention
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• 제17권6호
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• pp.2871-2876
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• 2016

The Pap smear test is recommended for early diagnosis of cervical cancer. The aim of this study was to assess knowledge and behavior regarding the Pap smear test based on the Health Belief Model (HBM) in women referred to premarital counseling classes, Hamadan, Iran. This quasi-experimental study was conducted on 330 women, who were allocated randomly to two case and control groups (n=165). Two educational session classes were performed in the case group. Two stages in before and after intervention groups were evaluated. Analysis of data was performed by SPSS/16.0, using t-test, $x^2$, and McNemar's test. P-values <0.05 were regarded as significant. There was no significant difference between the mean scores of the various structures of this model in two groups before the intervention. However, after the intervention there were significant increase in mean score of knowledge and all variables of HBM in the intervention group(P<0.001). The findings of this study highlight the important role of education about cervical cancer on changing women's beliefs about cervical screening.

• 약학회지
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• 제41권4호
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• pp.439-443
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• 1997

From the root bark of Broussonetia kazinoki (Moraceae) two antioxidant components were identified. Their structures were determined as kazinol A (1) and kazinol E (2) (is oprenylated flavan and isoprenylated 1,3-diphenyl propan derivatives) by comparing NMR data with those of the reported compounds from relative plants. The antioxidant activity of 1 and 2 were monitored by the method of DPPH radical scavenging activity, whose $SC_{50}$ values were $41.4{\mu}M\;and\;33.4{\mu}M$, respectively. These compounds also exhibited inhibitory activity against tyrosinase, which is the sole key enzyme for the melanin biosynthesis and play a role in conversion of tyrosine to dopa, and dopa to dopaquinone. The antioxidant effect and the suppression of melanin biosynthesis are useful for anti-aging, increasing vitality in the incidence of major degenerative diseases, and cosmetic products in relation to hyperpigmentation.

• 대한건축학회논문집:구조계
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• 제34권11호
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• pp.27-35
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• 2018

The purpose of this study is to examine the effects of boundary RC frame(composed of one tie-beam and two tie-columns) on seismic performance of unreinforced masonry walls to suggest alternative way for seismic design of unreinforced masonry wall structures. Two test specimens are prepared, one is a typical unreinforced masonry wall and another is alternative unreinforced masonry wall with additional boundary RC frame. The structural experiments were carried out to evaluate the difference of seismic resistance performance between two test specimens with or without the boundary RC frames. From the test results, it was found that the failure mode of unreinforced masonry wall fundamentally changed from 'brittle' to 'ductile' by the installing of boundary RC frames. And, the maximum load and energy dissipation capacity of the test specimen with boundary RC frame was increased about 1.6~1.7 and 2~3 times respectively compared with a typical unreinforced masonry wall specimen.

• 대한건축학회논문집:구조계
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• 제35권3호
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• pp.11-18
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• 2019

The purpose of this study was to estimate the resistance capacity of a traditional wooden house with shear walls made of wood panel. In order to achieve the purpose of the study, the load - displacement test was carried out and the resistance moment values of the shear walls were proposed. The shear walls were made by placing studs with a nominal dimension of $38mm{\times}89mm$ at intervals of 600 mm, and attaching 12 mm thick plywood with 8-d size pegs at intervals of 150 mm. The type of traditional building wall was classified and showed the moment resistance ability of each wall type. This value is expressed as a proportional value divided by the moment resisting capacity of the standard size shear walls not divided into the divided small frames. Although some frames have proportional values larger than 1.0 even though they have openings, most of them show values smaller than 1.0. Also, even without the openings, it showed a smaller value than 1, such as 0.84 and 0.67.

• 대한건축학회논문집:구조계
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• 제35권1호
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• pp.21-28
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• 2019

This study investigates the applicability of composite polyurea to contain fiber reinforcement like fiber glass, steel fiber and carbon nanotube. Polyurea as elastomer is an excellent water-proofing material with many mechanical characteristics such as high tensile strength, ductility, high rate of expansion and contraction, and so on. The reinforcing fibers can be utilized for improving the load-carrying capacity of concrete structures. The polyurea plays a role to improve the ductility and toughness. Composite polyurea takes the mechanical advantages of the fibers and the polyurea. The test variables include the type of reinforcing fiber, its spraying thickness, and its weight ratio contained in the composite polyurea. It is observed that the load-carrying capacity, and the ductility and toughness are improved with the increase in the spraying thickness and the weight ratio contained in the composite polyurea. It is expected that the composite polyurea can be widely utilized in enhancing the structural and seismic performance.

• 대한건축학회논문집:구조계
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• 제35권5호
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• pp.153-160
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• 2019

The purpose of this study was to investigate the mechanical and durability characteristics of latex-modified concrete using ultra rapid hardening cement : four types of mechanical tests including compressive strength, modulus of elasticity, flexural strength and bond strength were performed; and seven types of durability tests including resistance of concrete to chloride ion penetration, freeze-thaw resistance, scaling resistance, coefficient of thermal expansion, cracking tendency, abrasion resistance and drying shrinkage were performed. Required material performance of each test was determined in accordance with the Korea specification for repair of concrete and pavement repairing materials. The test results satisfied the required material performances, and presented a good mechanical and durability characteristics. In particularly, the materials showed early development of compressive strength, flexural strength and bond strength at 3 and 4 hours after curing. SEM photos were also taken to investigate the micro structures of the materials after chloride ion penetration test.

• 대한건축학회논문집:구조계
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• 제36권1호
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• pp.137-146
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• 2020

In this study, various application schemes of seismic isolation system which can be applied to Hanok have been studied by analyzing its structural characteristics under seismic load. Structural stability of Hanok is more required against seismic load as Hanok becomes long-spanned and multi-storied. To meet this goal, it becomes necessary to study more advanced technology such as seismic isolation design as well as seismic control design and seismic resistant design suitable to Hanok. Seismic isolation systems have been successfully applied to RC and steel structures to improve structural performance during earthquakes. Based on these previous study, we proposed four application schemes of seismic isolation design suitable for Hanok and analyzed their structural characteristics and applicability to Hanok in conceptual level based on its structural characteristics. The proposed four schemes are base isolation method, ground isolation method, roof isolation method and intermediate-story isolation method. The applicability of the proposed method was evaluated by performing boundary nonlinear dynamic analysis to the typical Hanok for the two types of isolation method, that is, ground isolation method and roof isolation method, and the results showed that the proposed methods produced good performance enough to be applied to Hanok.