• 한국해양공학회지
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• 제29권6호
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• pp.445-453
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• 2015

The stress triaxiality and lode angle are known to be most dominant fracture parameters in ductile materials. This paper proposes a three-dimensional failure strain surface for a ductile steel, called a low-temperature high-tensile steel (EH36), using average stress triaxiality and average normalized lode parameter, along with briefly introducing their theoretical background. It is an extension of previous works by Choung et al. (2011; 2012; 2014a; 2014b) and Choung and Nam (2013), in which a two-dimensional failure strain locus was presented. A series of tests for specially designed specimens that were expected to fail in the shear mode, shear-tension mode, and compression mode was conducted to develop a three-dimensional fracture surface covering wide ranges for the two parameters. This paper discusses the test procedures for three different tests in detail. The tensile force versus stroke data are presented as the results of these tests and will be used for the verification of numerical simulations and fracture identifications in Part II.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 3차
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• pp.3-10
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• 2010

Case study was carried out on the interpretation of the mechanical behavior of a severely damaged reinforced earth wall comprising geotextile with the concrete panel facing. In this part I, the outline of the damaged reinforced earth wall is in detail described. The background and cause of the damage are discussed based on the results of site investigation. The engineering properties of the fill were examined by performing various in-situ and laboratory tests, including the surface wave survey (SWS), PS-logging, RI-logging, soaking test, the direct shear box (DSB) test, bender element (BE) test, etc. The background as well as the cause for the damage of the wall may be described such that i) a considerable amount of settlement took place over a 3m thick weak soil layer in the lower part of the reinforced earth due to seepage of rainfall water, ii) the weight of the upper fill was partially supported by the geo-textile hooked on the concrete panels (n.b., named conveniently "hammock state" in this paper), and iii) the concrete panels to form the hammock were severely damaged by the unexpectedly large downwards compression force triggered by the tension force of the geotextile. The numerical simulation for the hammock state of the wall, together with counter-measures to re- stabilize the wall is subsequently described in Part II.

• Nutrition Research and Practice
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• 제16권2호
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• pp.173-193
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• 2022

BACKGROUND/OBJECTIVES: Alzheimer's disease (AD) is one of the most representative neurodegenerative disease mainly caused by the excessive production of amyloid beta (Aβ). Several studies on the antioxidant activity and protective effects of Populus tomentiglandulosa (PT) against cerebral ischemia-induced neuronal damage have been reported. Based on this background, the present study investigated the protective effects of PT against cognitive impairment in AD. MATERIALS/METHODS: We orally administered PT (50 and 100 mg/kg/day) for 14 days in an Aβ_25-35-induced mouse model and conducted behavioral experiments to test cognitive ability. In addition, we evaluated the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum and measured the production of lipid peroxide, nitric oxide (NO), and reactive oxygen species (ROS) in tissues. RESULTS: PT treatment improved the space perceptive ability in the T-maze test, object cognitive ability in the novel object recognition test, and spatial learning/long-term memory in the Morris water-maze test. Moreover, the levels of AST and ALT were not significantly different among the groups, indicating that PT did not show liver toxicity. Furthermore, administration of PT significantly inhibited the production of lipid peroxide, NO, and ROS in the brain, liver, and kidney, suggesting that PT protected against oxidative stress. CONCLUSIONS: Our study demonstrated that administration of PT improved Aβ_25-35-induced cognitive impairment by regulating oxidative stress. Therefore, we propose that PT could be used as a natural agent for AD improvement.

• 동력기계공학회지
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• 제12권5호
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• pp.34-39
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• 2008

The combustion purpose of diesel engine is to reduce the emission of green gas and to produce high output. Generally, the regulation matter of emission gas is largely diveded by 'THC', 'NOx', 'CO' and 'PM'. Among those matters, the most problem is to disgorge into 'PM', the character of diesel combustion. Diesel PM can be controlled using Diesel Particulate Filter, which can effectively reduce the level of soot emissions to ambient background levels. $NO_2$ generated by the DOC is used to combust the carbon collected in the DPF at low temperature. To certificate DPF device that is suitable to domestic circumstances, it is necessary to exactly evaluate the DPF devices according to the regulation of DPF certificate test procedure fur retrofit. To do carry out the above-mentioned description the understanding of that regulation like the standard of PM reduction is needed. In this study the test procedure including test cycle and BPT test condition was examined, and also the test result for specific DPF was analyzed. In every test like field test, PM reduction efficiency test and Seoul-10 mode test, no defect was showed.

• 대한물리치료과학회지
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• 제27권2호
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• pp.88-95
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• 2020

Background: In the present study to investigate the immediate effects of standing position of the trunk stabilization exercise on Guillain-Barre syndrome patient's balance and gait abilities were examined. Design: Case report and conducted as a single-blind. Methods: Standing position of trunk stabilization exercise was conducted for five Guillain-Barre syndrome patient's who met the selection criteria were recruited. The subjects were conducted conservative exercise and trunk stabilization exercise. Conservative exercise was implemented for thirty min, five times for 8 weeks, and trunk stabilization exercise was implemented for 15 min. The participants' balance was measured via force plate (COP), functional reach test (FRT), timed up and go test (TUG), gait was measured using the 10 m walk test, and 6 minute walk test. Results: After training, the change values of the balance and gait ability in the subjects were significantly greater than pre-test. participants showed significant improvements in COP, FRT, TUG, 10 m walk test and 6 minute walk test pre and post the training (p<0.05). Conclusions: standing position of the trunk stabilization exercise was effective on Guillain-Barre syndrome patient's balance (COP, FRT, TUG) and gait (10 m walk test and 6 minute walk test) abilities were examined.

• 한국환경보건학회지
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• 제33권1호
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• pp.36-42
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• 2007

Diesel PM can be controlled using Diesel Particulate Filter, which can effectively reduce the level of soot emissions to ambient background levels. In the Heavy Duty Diesel area, the Continuously Regeneration trap has been widely applied in the retrofit market. As the Special act for the improvement of air quality in the capital area, the retrofit program for DPF to used diesel vehicle has progressed favorably and there are currently over 1,000 of these DPF in use in retrofit applications in korea. These DPF comprise a specially formulated Diesel Oxidation Catalyst upstream of a DPF. The $NO_2$ generated by the DOC is used to combust the carbon collected in the DPF at low temperature. To certificate DPF device that is suitable to domestic circumstances, it is necessary to evaluate exactly the DPF devices according to the regulation of DPF certificate test procedure for retrofit(ministry of environment(MOE) announcement NO. 2005-16). To do so the understand of that regulation like the standard of PM reduction rate is needed. In this study the test procedure including test cycle and BPT test condition was examined and also the test result for specific DPF was analyzed. In every test like field test, PM reduction efficiency test and seoul-10 mode test, no defect could be showed.

• 영어어문교육
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• 제13권3호
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• pp.253-273
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• 2007

This study explores issues on how students' variables are related to their educational achievement in English subject. The National Assessment of Educational Achievement (NAEA) is conduced every year to measure educational progress and achievement, and to monitor the quality of education at the national level and appropriateness of the national curriculum. It also serves the purpose to collect background information affecting educational achievement. The background information is gathered by using questionnaires for students, teachers and school administrators. Among the student variables in the national level educational achievement assessment is self-regulated learning, which is composed of self-efficacy, self-control and learning strategy. In the NAEA in 2005 it was found that the features of self-regulated learning were significantly correlated to test scores in English. The findings from the analysis of the trends of the relationships between test scores in English and information on students' self-regulated learning provide implications for the national curriculum as well as for learning and teaching.

• 대한임상검사과학회지
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• 제45권4호
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• pp.159-163
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• 2013

To investigate the cognitive degree about hepatitis and hepatosis, 916 subjects are examined with query and hepatotitis B, C, E test as well as s-AST and s-ALT as liver function test. Based on results, there are 4.9% of positive hepatitis and 8.9% of hepatosis and 13.8% of liver disorder. Among positive hepatitis, there are 93.3% of type B, 42.2% of type E and 6.7% of type C, respectively. From 45% of positive hepatitis B, they carry hepatitis B and E together. The cognitive degree about positive hepatitis is 64.4%, hepatosis 8.6%. The knowledge degree from cognitive group is higher than that of noncognitive group but there is no difference from hepatosis between two groups (p<0.001). The cognitive degree of liver disorder depends on academic background (p<0.001), mother's academic background (p<0.001), job (p<0.05) and family's income (p<0.001), showing significant difference. In summary, hepatitis carrier aware quite well about liver disorder but very low from hepatosis. Accordingly, the plan to increase a cognitive degree and continuous education as well as policy support to minimize spread of disease and to protect not to be worsen disease will be needed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.599-602
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• 2005

This paper describes a experimental study determining the effects of the type and loudness of introducing sounds on the amenity and the masking degree of background noise. 132 relative test sounds with 11 types of introducing sounds and 3 steps of road traffic noise were presented to 29 subjects through headphone in the laboratory experiment. Seven scale of polar adjective such as 'Strong Weak', 'Pleasant Unpleasant', 'Clear Unclear', 'Suitable Unsuitable', 'Comfortable-Discomfortable' was employed for the evaluation of amenity. And Seven scale of mono polar adjective such as 'Very-Not at all' was employed for the evaluation of masking degree against road traffic noise. The results are as follows; Green music was evaluated the highest amenity among test sounds and murmurs of a stream, signal music, song of a bird, crying of insect was showed the amenity rank of order. The softer and weaker introducing sound was evaluated more suitable and comfortable under the road traffic noise. So adequate level of introducing sounds was considered for the desirable urban soundscape. Also the louder sounds compared to background noises had greater masking effects. But similar levels of introducing sounds were recommended considering both good amenity and masking effects.

• 한국음향학회지
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• 제10권1호
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• pp.5-11
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• 1991

명료도시험은 실내에서 음성이 정확히 전달되는 정도를 정량화할 수 있는 유용한 건축음향의 지표중 하나이다. 많은 나라에서 이미 표준화하여 사용하고 있듯이, 한국어에 적합한 명료도시험의 기준이 1989년에 제안되었으며, 안정적인 배경소음조건에서 위의 시험방법은 그 타당성이 입증된 바 있다. 이 논문에서는 위의 제안된 명료도 시험방법이 변동하는 외부소음의 조건에서도 유용하게 적용될 수 있는지를 검증하고자 하였다. 소음레벨이 시간에 따라 변화하는 26개 교실에서 수행한 명료도시험과 음향측정에 의하여, 한국어 음원에 대하여 제안된 명료도시험 방법은 실내의 청취조건을 평가하는 유용한 수단이 될 수 있음이 밝혀졌다.