• Nuclear Engineering and Technology
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• v.32 no.1
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• pp.57-66
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• 2000

The RELAP5 code has been developed for best-estimate simulation of transients and accidents for pressurized water reactors and their associated systems, but it has not been fully assessed for those of CANDU reactors. However, a previous study suggested that the RELAP5 code could be applicable to simulate the transients and accidents for CANDU reactors. Nevertheless, it is indicated that there are some works to be resolved, such as modeling of headers and multi-channel simulation for the reactor core, etc. Therefore, this study has been initiated with an aim to identify the code applicability for all the postulated transients and accidents in CANDU reactors. In the present study, the small inlet header break experiment (B8604) in the RD-14 test facility was simulated with RELAP5/MOD3.2 code. The RELAP5 results were also compared with both experimental data and those of CATHENA analyses performed by AECL and the analyses demonstrated the code's capability to predict major . phenomena occurring in the transient with sufficient accuracy for both Qualitative and quantitative viewpoint However, some discrepancies in the depressurization of the primary heat transport system after the break and the consequent time delay of the major phenomena were also observed.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.135.2-135
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• 1999

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1448-1459
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• 2023

A key element of the safety analysis is Loss of Coolant Analysis (LOCA) which must be performed using system thermal-hydraulic codes. These codes are extensively validated against separate effect and integral experiments. RELAP/SCDAPSIM is one such code that may be used to predict LBLOCA response in a CANDU reactor. The RD-14M experiment selected for the Best Estimate Plus Uncertainty study is a 44 mm (22.7%) inlet header break test with no Emergency Coolant Injection. This work has two objectives first is to simulate pipe break with RELAP and compare these results to those available from experiment and from comparable TRACE calculations. The second objective is to quantify uncertainty in the fuel element sheath (FES) temperature arising from model coefficient as well as input parameter uncertainties using Integrated Uncertainty Analysis package. RELAP calculated results are found to be in good agreement with those of TRACE and with those of experiments. The base case maximum FES temperature is 335.5 ℃ while that of 95% confidence 95^th percentile is 407.41 ℃ for the first order Wilk's formula. The experimental measurements fall within the predicted band and the trends and sensitivities are similar to those reported for the TRACE code.

• Nuclear Engineering and Technology
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• v.35 no.5
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• pp.426-441
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• 2003

A reactor inlet header break experiment, B9401, performed in the RD-14M multi channel test facility was analyzed using RELAP5/MOD3.2 and RELAP5/CANDU[1]. The RELAP5 has been developed for the use in the analysis of the transient behavior of the pressurized water reactor. A recent study showed that the RELAP5 could be feasible even for the simulation of the thermal hydraulic behavior of CANDU reactors. However, some deficiencies in the prediction of fuel sheath temperature and transient behavior in athe headers were identified in the RELAP5 assessments. The RELAP5/CANDU has been developing to resolve the deficiencies in the RELAP5 and to improve the predictability of the thermal-hydraulic behaviors of the CANDU reactors. In the RELAP5/CANDU, critical heat flux model, horizontal flow regime map, heat transfer model in horizontal channel, etc. were modified or added to the RELAP5/MOD3.2. This study aims to identify the applicability of both codes, in particular, in the multi-channel simulation of the CANDU reactors. The RELAP5/MOD3.2 and the RELAP5/CANDU analyses demonstrate the code's capability to predict reasonably the major phenomena occurred during the transient. The thermal-hydraulic behaviors of both codes are almost identical, however, the RELAP5/CANDU predicts better the heater sheath temperature than the RELAP5/MOD3.2. Pressure differences between headers govern the flow characteristics through the heated sections, particularly after the ECI. In determining header pressure, there are many uncertainties arisen from the complicated effects including steady state pressure distribution. Therefore, it would be concluded that further works are required to reduce these uncertainties, and consequently predict appropriately thermal-hydraulic behaviors in the reactor coolant system during LOCA analyses.

• Geotechnical Engineering
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• v.2 no.1
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• pp.7-14
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• 1986

The structure of the collapsible soils, such as decomposed granite soil and loess, were examined by the odeometer test, SEM & XES analysis and static & cyclic triaxial test, and hove this structure have influences upon the collapsible behaviour under static and cyclic load was investigated. The study results obtained are as follows; 1. The macropores space of decomposed granite soil (rd=1.50g/cm3) and loess (rd=1.43g/cm3) used in this test were well developed, and showed the behaviour of collapsible soil. 2. Collapsible soil has high resistance on the strain under natural moisture content, however, the resistance on the strain was sharply decreased by the absorption and increasing load since its special structure was destructed. 3. Under the static load, the strain of collapsible soil was high by the viscous flow of the cyclic bonds with time lapse, but Infer the cyclic load, the strain of collapsible soil was low since the tinge needed to destruct the bonding force of clay was not enough. 4. The understanding about the cyclic behaviour of collapsible soil may be helpful to predict the elastic & residual strain of the foundations by the earthquake together with the damage by the additional failure.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.53-62
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• 1990

This experiment was performed to clarify the effects of /sup 60/Co gamma irradiation on secretory function, amylase activity and contents of nucleic acids of parotid gland in rat. Experimental animals were divided into 6th hours, 3rd, 7th, 14th and 28th days after irradiation and control. The experimental animals are singly irradiated with 20Gy (2,000rad) through protective lead block. Secretory function of parotid gland was evaluted by uptake and clearance of /sup 99m/TcO₄. /sup 99m/TcO₄. 0.2μ ci/gm, was injected into peritonium in uptake groups. Rats were sacrified with cervical dislocation after 30 minutes and gland was excised. In the clearance group. pilocarpine nitrate (8㎎/㎏) was intraperitoneally injected at 30 minutes after /sup 99m/TcO₄ injection and rats were sacrified 30 minutes after pilocarpine injection. Radioactivity of excised parotid gland was measured by using of gamma counter and stimulation-secretion coefficients, uptake radioactivity divided by clearance radioactivity, was calculated. Amylase activity and contents of DNA and RNA were determined by spectrophotometry. The results obtained were as follows: 1. In the uptake test, the radioactivity of /sup 99m/TcO₄ per unit weight increase in experimental group except 6th hours group, compared with control groups and showed a peak at 3rd days after irradiation. 2. In the clearance test, the radioactivity of /sup 99m/cO₄per unit weight rose to a peak at 3rd days after irradiation and gradually recovered thereafter. 3. Stimulation-secretion coefficient of parotid gland decreased at 6th hours, 3rd and 7th days after irradiation, and gradually increased. 4. Amylase activity of parotid gland decreased in 3rd and 7th days group, and especially lowest in 3rd days after irradiation. 5. The contents of DNA showed no definite difference in all the experimental groups, but RNA was seemed to decrease with time after irradiation.

• Korean Journal of Child Studies
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• v.14 no.1
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• pp.129-139
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• 1993

The purpose of this study was (1) to explore the dimensions of children's self-esteem and (2) to explain the development of children's self-esteem through a short-term longitudinal approach. 219 children in 1st, 3rd, and 5th grades participated twice once each year over a 2 year period. Factor analysis, Pearson's correlation, Cronbach alpha, pairs t-test, and MANOVA were conducted. Instruments used in this study were made by present researchers. The results showed that (1) children's self-esteem consisted of the cognitive-competence self, peer-related self, teacher-related self, family self, negative self, and physically competent self: (2) the lst and 2nd grade children's self-esteem was higher than that of 3rd-6th grade children and the 3rd grade children's self-esteem changed little until they reached 5th grade, but the 6th grade children's self-esteem decreased.

• Education of Primary School Mathematics
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• v.14 no.1
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• pp.69-79
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• 2011

The purpose of this study is to analyze 3rd, 4th and 5th graders' probability understanding and raise issues concerning instructional methods and search for the possibility of learning probability. For the purpose, a descriptive study through pencil-and-paper test regarding fairness, sample space, probability of event, probability comparison, independence and conditional probability was conducted. The following conclusions were drawn from the results obtained in this study. First, the 3rd, 4th, and 5th grade students scored the highest in the sample space questions. In descending order of skill, the students scored the highest in sample space following probability of events, fairness and probability comparison. Second, however, the level of independence understanding was low. There was no meaningful differences between grades and the conditional probability was the least understood. The independence is difficult to develop naturally according to cognitive development. The conditional probability recognizing the probability of an event changes in non-replacement situations was very difficult for these students. Third, there were significant differences between the 5th graders and the 3rd and 4th graders in the probability comparison questions. It shows that 5th graders understand the concept of proportion when they compare equal ratio probability of an event. The 3rd graers could do different ratio probability of an event more easily than equal ratio probability of an event after they were instructed on probability comparison.

• Journal of Korean Biological Nursing Science
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• v.14 no.2
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• pp.84-93
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• 2012

Purpose: This study was performed to identify the effects of dance sports programs on the parameters of health promotion (blood pressure, pulse, glucose, blood lipids, musculoskeletal pain, fatigue, self-efficacy, and depression) in rural women. Methods: A non-equivalent control group pretest-posttest experimental design was used. The study subjects were 38 women who were aged 45-78 and cultivating perilla leaves in a rural area. An experimental group (n=20) received the dance sports program from December 3rd, 2009 to June 3rd, 2010 and a control group (n=18) did not. Data was collected 3 times (before the program, 12 during and 24 weeks after the program) and were analyzed with $X^2$ test, t-test, and Repeated Measures ANOVA using SPSS/WIN 18.0. Results: For the experimental group, significant improvement was found in high density lipoprotein cholesterol (HDL-C), low density cholesterol (LDL-C), triglyceride (TG) musculoskeletal pain, fatigue, self-efficacy, and depression as compared to the control group. Conclusion: The findings of the study indicates that the dance sports program is effective on health promotion for rural women. Therefore, dance sports programs can be recommended for health promotion of rural residents.

• KCI Concrete Journal
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• v.14 no.2
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• pp.86-91
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• 2002

This paper presents an experimental study to investigate the behavior of mechanical anchorage of reinforcing bars in concrete members. Three kinds of mechanical anchorage which are a kind of headed reinforcements are considered in this study. Total seven specimens were prepared to consider the effects of anchoring methods (Type A, Type B and Type C) and anchorage lengths of the reinforcing bars (14 $d_{b}$, 12 $d_{b}$, 9 $d_{b}$). Pullout tests conforming to ASTM were carried out to assess the effects of several variables on anchoring strength of bars. Based on the test results, it was concluded that the behavior of the specimen anchored by the mechanical anchorage with the anchor-age length of 12 $d_{b}$, is as good as, or better than that of the specimen anchored by 90-degree standard hook.rd hook.