• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.129-134
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• 2000

Recently, HIPS(High Impact Polystyrene) materials are spot-lighted as office equipment, home electronics, electronics appliances housing, packing containers, etc. But its using are occur to problem caused by fatigue fracture. However, its strength is larged affected by environmental conditions. So, in this paper it tried to analyze the effect of temperature by tensile test and fatigue test. It was observed that yield strength and ultimate strength, fatigue life of same stress decreased relatively with increase temperature. Further, this paper predict S-N curve using the result of tensile test and micro vickers hardness test. For this purpose, the management in the engineering department is able to design the fatigue life of HIPS(HR-1360) materials.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.181-186
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• 2001

High speed railroad noise is one of the main causes of environmental impact. An estimate of the relevant noise levels is usually required in order to evaluate the noise barrier and the anti-noise trailer. This paper introduce the test procedure and the estimate for HST noise. The aim of this is to measure, by means of a test, the level of acoustic pressure present during the passing of a KTX(Korea Train Express), in order to satisfy the contractual requirements and the noise criteria. A number of measurements are carried out in order to estimate noise impact by HST along test track.

• 한국지반환경공학회 논문집
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• 제12권4호
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• pp.17-24
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• 2011

차수 및 지반안정을 목적으로 규산나트륨을 사용한 기존의 알칼리성 물유리계 약액주입공법은 주입 후 시간경과에 따라 지하수에 의해 주입고결체로부터 알칼리성분의 용탈이 진행되어 내구성이 약해지고 지하수를 오염시키는 문제점이 있다. 따라서 본 연구에서는 규산나트륨 주입재의 문제점을 보완하기 위해 개발된 알칼리성 실리카졸 지반주입재의 효과를 규명하는 데에 그 목적이 있다. 연구비교대상으로는 규산나트륨 주입재와 알칼리성 실리카졸 주입재로 하였다. 규산나트륨과 알칼리성 실리카졸 용액에 대하여 보통 포틀랜트 시멘트와 고로 슬래그 시멘트를 각각 배합하여 총 4가지의 Case로 나누어 공시체를 제작하여 시험을 실시하였다. 재령에 따른 일축압축강도 시험을 실시하였고, 환경영향성평가를 위하여 어독성시험과 pH시험을 실시하여 비교 및 분석을 하였다. 본 연구를 통해 고로 슬래그 시멘트를 배합한 알칼리성 실리카졸 지반주입재가 우수한 강도와 친환경성을 가지고 있는 것으로 나타났다.

• Journal of Korean Biological Nursing Science
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• 제18권4호
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• pp.274-279
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• 2016

Purpose: Adolescents who experienced the alcohol consumption have gradually increased. Adolescence is a critical period of the neural plasticity in the brain. Neural plasticity is mediated by neurotrophins and has an impact on cognitive function. Environmental enrichment ameliorates the cognitive function and increases neurotrophins. Thus, we investigated the neuroprotective effect of environmental enrichment on ethanol induced cognitive impairment in adolescent rats. Methods: The ethanol groups and the controls groups were injected with ethanol (0.5g/kg) and phosphate buffered saline, respectively, through intraperitoneal from 28th day of birth for 11 days. The environmental enrichment groups were provided larger cages containing toys than the standard cage. Passive avoidance test and Y-maze test were performed to evaluate the spatial memory. Results: Environmental enrichment+ethanol group showed higher alterations than the standard environment+ethanol group in Y-maze test (p<.05). In hippocampus, The environmental enrichment+ethanol group showed significantly higher level of the number of c-fos positive celsl and density of tropomyosin receptors kinase B receptor than the standard environment+ethanol group (p<.05). Conclusion: So, we suggested that the environmental enrichment played a role as a prophylaxis for prevention of memory impairment induced by ethanol exposure in adolescence.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.269-280
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• 2020

The study investigates Environmental Accounting Information (EAI) as well as factors affecting the environmental accounting implementation by the construction firms listed on the Ho Chi Minh Stock Exchange (HOSE), Vietnam. After eliminating seven enterprises that lacked data, the authors selected a sample of 112 observations from 28 construction businesses listed on the Ho Chi Minh Stock Exchange in the period 2015-2018. This study uses research data extracted from the companies' annual reports. Then, the data are analyzed by Stata 13 software, including descriptive statistics, correlation coefficient analysis, regression analysis of table data using estimation methods (Pooled OLS, REM, FEM), and testing of model defects (heteroskedasticity test, multicollinearity test, autocorrelation test). The results show that construction companies listed on the Ho Chi Minh Stock Exchange have out factors affecting the environmental accounting implementation by these enterprises, including independent audit firm and listed time. While the independent auditor firm has a positive and significant impact, the listed time has a negative influence. In addition, our study has confirmed the role of institutional factors affecting the disclosure level of EAI on the implementation of environmental accounting by construction enterprises listed on the Ho Chi Minh Stock Exchange.

• 한국지반환경공학회 논문집
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• 제23권10호
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• pp.13-19
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• 2022

본 연구는 암석의 압축강도를 비파괴적으로 산정하기 위하여 암석시편 초기타격 및 반발에 의한 연속적인 반복타격 시 발생하는 타격력에 대한 응답신호를 모두 측정하고 이를 누적한 전체 타격력 신호에너지를 이용하고 그 결과를 제시하는 것에 관한 것이다. 본 연구에서는 이를 위해서 타격 및 측정장치를 고안 및 셋업하였고 이를 이용하여 암석시편을 회전 자유낙하에 의해 초기 타격토록하고 반발작용에 의한 반복타격이 이루어질 수 있도록 하였다. 본 연구에서는 서로 다른 세 종류의 암석시편에 대하여 타격력실험을 실시하고 발생신호를 측정하였다. 각 시편별 초기 및 반발타격으로부터 발생된 신호로부터 산정된 전체 타격력 신호에너지와 각 시편별 측정한 직접압축강도와 상호 비교하였다. 비교결과, 타격력 응답신호로 부터 산정된 전체 타격력 신호에너지는 시편의 직접압축강도와 직접적인 관계가 있다는 것을 확인하였으며, 이를 통해 암석의 압축강도는 타격 시 발생하는 타격력 응답신호로부터 산정된 전체 타격력 신호에너지를 이용하여 비파괴적으로 산정할 수 있음을 알 수 있었다.

• 아태비즈니스연구
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• 제12권3호
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• pp.175-192
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• 2021

Purpose - In this study, we investigate the effects of government environmental subsidies and the globalization Chinese firms on their profitability using return on assets (ROA). Design/methodology/approach - In this study, a merged data including accounting, financial market, subsidization of the Chinese governments, local and the central, and export activities of 19,563 year-firms, for those listed on Shanghai Stock and Shenzhen Stock Exchange for 11 years from 2008 to 2018 is used. We collect subsidy data from RESSET database and financial data from CSMAR database. Then, we empirically test the test hypotheses using fixed effects models (FEM) separately and in a simultaneous equation model (SEM). Findings - Firstly, the globalization of Chinese firms has a negative impact on their profitability for some years after the year. Secondly, environmental subsidies just like other subsidies have ameliorating effects on financial performance for global firms. Such effects have lasted some years. Thirdly, environmental investments have a mostly negative impact on short- and long-term profitability for global firms. Lastly, the government's environmental subsidies in China have a positive effect on their profitability for both global and domestic firms. Research implications or Originality - We can infer that environmental investments with the help of the governmental subsidies can help Chinese firms deploy global strategies to expand markets to surpass competitors in the long run despite worsening profitability in global markets in the short run.

• 항공우주시스템공학회지
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• 제2권2호
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• pp.1-7
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• 2008

Recently the wind energy has been alternatively used as a renewable energy resource instead of the mostly used fossil fuel due to its lack and environmental issues. This work is to propose a structural design and analysis procedure for development of the low noise 100W class small wind turbine system which will be applicable to relatively low speed region like Korea and for the domestic use. Structural analysis including load cases, stress, deformation, buckling, vibration and fatigue life was performed using the Finite Element Method, the load spectrum analysis and the Miner rule. In order to evaluate the designed structure, the structural test was carried out and its test results were compared with the estimated results. In addition, the blade should be safe from the impact damage due to FOD(Foreign Object Damage) including the bird strike. In order to analize the bird strike penomena on the blade, MSC. Dytran was used, and the applied method Arbitrary Lagrangian-Eulerian was evalud by comparison with the previous study results.

• 한국지반공학회논문집
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• 제35권11호
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• pp.25-36
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• 2019

차량이 도로를 이탈하여 성토부로 추락하는 것을 방지하기 위해 설치되는 연성 차량방호울타리는 사면부 시작점 근처에 도로방향으로 일렬로 근입된 무리말뚝과 무리말뚝 위에 부착되는 가드레일로 구성되어 있다. 차량방호울타리에 차량 충돌 시, 충돌에너지의 일부는 가드레일의 변형에 의해 흡수되며, 나머지 에너지는 가드레일을 지지하는 말뚝과 지반의 상호작용으로 저항하게 된다. 본 논문에서는 충격하중에 대한 말뚝과 지반의 상호작용을 원심모형실험을 수행하여 분석하였다. 풍화토로 다져진 경사지반에 설치된 단말뚝의 충격하중에 대한 극한지지력 및 거동특성을 분석하고자 하였다. 이를 위해 말뚝에 충격하중을 모사할 수 있는 하중재하시스템을 설계 및 구축하였다. 구축된 원심모형실험체 및 하중재하시스템을 이용하여 하중 및 지반조건에 대한 매개변수연구를 수행하였다. 최종적으로, 말뚝의 하중재하점에서 나타나는 하중-변위 곡선을 계측하여 충격극한지지력을 분석하였다. 또한, 휨모멘트 분포도로부터 산정된 지반반력 분포도를 도출하였고, 선행 연구결과와 비교하여 차량 방호울타리 지지말뚝의 지지거동을 분석하였다.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.241-251
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• 2021

This research explores and develops digital transformation factors influencing the logistics service-provider sector in Thailand while also examining the impact sustainability factors associated with digital transformation. Divided into two parts, Part one of the theoretical study framework covers 21 factors relating to logistics, including drivers, objectives, implications, and success factors. The second part concerns 23 factors associated with logistics sustainability, including economic, environmental, and social aspects. This quantitative empirical research was conducted using an online questionnaire instrument, and a structural equation modeling (SEM) technique was used to test the proposed model. The findings from 545 samples collected between August and November 2020 from respondents working in logistics service-provider companies in Thailand show that digital transformation drivers and objectives seem likely to impact success factors and implications in digital transformation positively. Digital transformation success factors also positively impact logistics sustainability. In comparison, logistics sustainability has a significant impact on Thailand's logistics service-provider sector's economic, environmental, and social aspects. Lastly, this research highlights the significance of digital transformation success factors and extends the current knowledge about digital transformation factors and their potential impact on logistics sustainability.