• 제목/요약/키워드: role stress

검색결과 2,719건 처리시간 0.031초

유리기판 위에 형성된 Al/Ni 및 TiW/Ni 다층 금속배선막의 계면 접합력 및 나노압입특성 평가 (Measurement of Adhesion Strength and Nanoindentation of Metal Interconnections of Al/Ni and TiW/Ni Layers Formed on Glass Substrate)

  • 조철민;김재호;황소리;윤여현;오용준
    • 대한금속재료학회지
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    • 제48권12호
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    • pp.1116-1122
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    • 2010
  • Metal interconnections of multilayer Al/Ni and TiW/seed-Ni/Ni were formed on glass, and the adhesion strength and nanoindentation response of the composite layers were evaluated. The Al/Ni multilayer was formed by an anodic bonding of glass to Al and subsequent electroless plating of Ni, while the TiW/Ni multilayer was fabricated by sputter deposition of TiW and seed-Ni onto glass and electroless plating of Ni. Because of the diffusion of aluminum into glass during the anodic bonding, anodically bonded glass/Al joint exhibited greater interfacial strength than the sputtered glass/TiW one. The Al/Ni on glass also showed excellent resistance against delamination by bending deformation compared to the TiW/seed-Ni/Ni on glass. From the nanoindentation experiment of each metal layer on glass, it was found that the aluminum layer had extremely low hardness and elastic modulus similar to the glass substrate and played a beneficial role in the delamination resistance by lessening stress intensification at the joint. The indentation data of the multilayers also supported superior joint reliability of the Al/Ni to glass compared to that of the TiW/seed-Ni/Ni to glass.

Impact of the Mekong River Flow Alteration on the Tonle Sap Lake in Cambodia

  • Lee, Giha;Kim, Joocheol;Jung, Kwansue;Lee, Hyunseok
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2015년도 학술발표회
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    • pp.231-231
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    • 2015
  • Rapid development in the upper reaches of the Mekong River, in the form of construction of large hydropower dams and reservoirs, large irrigation schemes, and rapid urban development, is putting water resources under stress. Many scientific reports have pointed out that cascade dams along the Mekong River lead to serious problems: not only hydrologically but also a decline of agricultural productivity due to a decrease of sediment supply in the Mekong Delta and a change of fish amount due to drastic change of the water environment. Cambodia and Vietnam, located in the lowest Mekong basin, are gravely affected by radical changes of hydrologic regime due to Mekong River developments. In particular, the Tonle Sap Lake in Cambodia is very sensitive to the flood cycle and flow variation of the Mekong River as well as inflow water quality from the Mekong River. More than 50% of Cambodian GDP depends on the primary industries such as agriculture, fishing, and forestry, and the Tonle Sap Lake plays an important role to support the national economy in Cambodia. In addition, Cambodian people usually take nourishment from the fish of Tonle Sap Lake. This research aims to assess the impacts of the Mekong river flow alternation on the hydrologic regime of the Mekong River - Tonle Sap Lake. We carried out rainfall-runoff-inundation simulation using CAESER-LISFLOOD for integrated water resource management in the Tonle Sap Basin and then analyze flood inundation variation of the Tonle Sap Lake due to the scenarios. Furthermore, the simulated inundation maps were compared to MODIS satellite images for model verification and hydrologic prediction.

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Nonlinear interaction behaviour of plane frame-layered soil system subjected to seismic loading

  • Agrawal, Ramakant;Hora, M.S.
    • Structural Engineering and Mechanics
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    • 제41권6호
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    • pp.711-734
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    • 2012
  • The foundation of a tall building frame resting on settable soil mass undergoes differential settlements which alter the forces in the structural members significantly. For tall buildings it is essential to consider seismic forces in analysis. The building frame, foundation and soil mass are considered to act as single integral compatible structural unit. The stress-strain characteristics of the supporting soil play a vital role in the interaction analysis. The resulting differential settlements of the soil mass are responsible for the redistribution of forces in the superstructure. In the present work, the nonlinear interaction analysis of a two-bay ten-storey plane building frame- layered soil system under seismic loading has been carried out using the coupled finite-infinite elements. The frame has been considered to act in linear elastic manner while the soil mass to act as nonlinear elastic manner. The subsoil in reality exists in layered formation and consists of various soil layers having different properties. Each individual soil layer in reality can be considered to behave in nonlinear manner. The nonlinear layered system as a whole will undergo differential settlements. Thus, it becomes essential to study the structural behaviour of a structure resting on such nonlinear composite layered soil system. The nonlinear constitutive hyperbolic soil model available in the literature is adopted to model the nonlinear behaviour of the soil mass. The structural behaviour of the interaction system is investigated as the shear forces and bending moments in superstructure get significantly altered due to differential settlements of the soil mass.

Protective Effect of Korean Panax ginseng against Chromium VI Toxicity and Free Radicals Generation in Rats

  • Abdel-Wahhab Mosaad A.;Ahmed Hanaa H.
    • 고려인삼학회:학술대회논문집
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    • 고려인삼학회 2002년도 학술대회지
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    • pp.351-365
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    • 2002
  • Earlier studies have demonstrated that chromium (Cr) VI compounds have been shown to be more toxic and carcinogenic than other chromium compounds. The aim of the present work was to evaluate the antioxidant effects of red ginseng against chromium VI -induced toxicity and free radical generation. Sixty adult male rats were divided into six equal groups include: control group, group received Cr VI alone (50 mg/kg b.w.), group treated with Korean ginseng (K. ginseng) alone (20 mg/kg b.w), group treated with Cr VI for 15 days then received K. ginseng for other 15 days, group treated with Cr VI and K. ginseng at the same time for 15 days, and group treated with K. ginseng for 15 days then Cr VI for other 15 days. The results revealed that Cr VI caused significant increase in ALT, AST, ALP, G-GT, urea, creatinine, and acid phosphatase. Whereas, it caused significant decrease in TP, albumin, testosterone, GPX, and SOD indicating a stress for liver, kidney and testes. K. ginseng alone caused significant increase in GPX and SOD activities in healthy animals and this result suggests a prophylactic role for this herb in protection against the damaging impact induced by free radical species. Furthermore, the other biochemical parameters measured after K. ginseng administration were comparable to the control values. Treatment with Cr VI followed by K. ginseng, Cr VI and K. ginseng or K. ginseng followed by Cr VI resulted in significant improvement in all tested parameters towards the normal values of the controls. However, this improvement was pronounced in the group pre-treated with K. ginseng for 15 days before Cr VI administration. It could be concluded that K. ginseng exhibited a protective action against the toxic effects of Cr VI and it had the ability to scavenge free radicals resulted from Cr VI intoxication.

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국내 간호전문직관 연구 주제 동향: 텍스트네트워크분석과 토픽모델링의 융합 (Trends in the Study of Nursing Professionals in Korea: A Convergence Study of Text Network Analysis and Topic Modeling)

  • 박찬숙
    • 한국융합학회논문지
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    • 제12권9호
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    • pp.295-305
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    • 2021
  • 본 연구의 목적은 국내에서 발표된 간호전문직관 연구 주제 동향을 양적 내용분석을 통해 탐색하는 것이다. 연구방법은 학술논문수집, 단어 정제 및 추출, 자료 분석의 절차를 수행하였다. 351편의 논문을 수집하여 영문초록에서 단어를 추출하여 텍스트네트워크를 개발하였고, 네트워크분석과 토픽모델링을 융합하여 자료를 분석하였다. 연구결과 핵심 주제는 간호사, 간호전문직관, 간호학생, 간호, 전문직자아개념, 보건의료인, 만족, 임상역량, 자기효능감 등이었다. 토픽모델링을 통해 간호사 전문직관, 간호학생 전문직관, 간호전문직 정체성, 간호역량의 토픽그룹을 파악하였다. 시간이 흘러도 핵심 주제는 변화가 없었지만, 1990년대 역할갈등, 윤리적 가치, 2000년대 셀프리더십, 사회화, 2010년대 임상실습스트레스, 지지체계와 같은 주제들이 부상하였다. 결론적으로 본 연구를 통해 국내에서 임상간호사와 간호학생의 간호전문직관과 이에 영향을 미치는 요소들에 대한 연구가 활발하게 발표되고 있었으나, 간호전문직관 형성 및 향상에 효과적인 다차원적인 중재 전략을 모색한 연구는 부족하였음을 알 수 있었다.

How Much Does My Work Affect My Health? The Relationships between Working Conditions and Health in an Italian Survey

  • Ronchetti, Matteo;Russo, Simone;Di Tecco, Cristina;Iavicoli, Sergio
    • Safety and Health at Work
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    • 제12권3호
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    • pp.370-376
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    • 2021
  • Backround: Working condition surveys are widely recognized as useful tools for monitoring the quality of working life and the improvements introduced by health and safety policy frameworks at the European and national level. The Italian Workers' Compensation Authority carried out a national survey (Insula) to investigate the employer's perceptions related to working conditions and their impact on health. Methods: The present study is based on the data collected from the Italian survey on health and safety at work (INSULA) conducted on a representative sample of the Italian workforce (n = 8,000). This focuses on the relationship between psychosocial risk factors and self-reported health using a set of logistic and linear regression models. Results: Working conditions such as managerial support, job satisfaction, and role act as protective factors on mental and physical health. On the contrary, workers' risk perceptions related to personal exposure to occupational safety and health risks, concern about health conditions, and work-related stress risk exposure determine a poorer state of health. Conclusions: This study highlights the link between working conditions and self-report health, and this aims to provide a contribution in the field of health at work. Findings show that working conditions must be object of specific preventive measures to improve the workers' health and well-being.

Thermal-fluid-structure coupling analysis for plate-type fuel assembly under irradiation. Part-I numerical methodology

  • Li, Yuanming;Yuan, Pan;Ren, Quan-yao;Su, Guanghui;Yu, Hongxing;Wang, Haoyu;Zheng, Meiyin;Wu, Yingwei;Ding, Shurong
    • Nuclear Engineering and Technology
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    • 제53권5호
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    • pp.1540-1555
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    • 2021
  • The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect its stress conditions, mechanical behavior and thermal-hydraulic performance. A reliable numerical method is of great importance to reveal the complex evolution of mechanical deformation, flow redistribution and temperature field for the plate-type fuel assembly under non-uniform irradiation. This paper is the first part of a two-part study developing the numerical methodology for the thermal-fluid-structure coupling behaviors of plate-type fuel assembly under irradiation. In this paper, the thermal-fluid-structure coupling methodology has been developed for plate-type fuel assembly under non-uniform irradiation condition by exchanging thermal-hydraulic and mechanical deformation parameters between Finite Element Model (FEM) software and Computational Fluid Dynamic (CFD) software with Mesh-based parallel Code Coupling Interface (MpCCI), which has been validated with experimental results. Based on the established methodology, the effects of non-uniform irradiation and fluid were discussed, which demonstrated that the maximum mechanical deformation with irradiation was dozens of times larger than that without irradiation and the hydraulic load on fuel plates due to differential pressure played a dominant role in the mechanical deformation.

포스트 코로나19 시대의 패션 소비문화에 대한 빅데이터 분석 -중국 패션 네트워크인 LADYMAX.cn의 기사를 중심으로- (Fashion Consumption Culture in the Post-COVID-19 Era Identified through Big Data Analysis -Focusing on Articles in the Chinese Fashion Network LADYMAX.cn-)

  • 빈삼;염혜정;심수인
    • 패션비즈니스
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    • 제25권2호
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    • pp.80-97
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    • 2021
  • In this study, the changes in fashion consumption culture in the post-COVID-19 era were examined through big data analysis. Considering that the Chinese market plays a pivotal role in the global fashion industry, big data was collected in the most famous and professional fashion network in China, LADYMAX.cn. As a result of text mining and social network analysis, three major changes were identified as the emerging fashion consumption culture in the post-COVID-19 era. First, as a trend in new media consumption, COVID-19 disease and the development of digital technology tended to encourage consumers to put more importance on the relationship between bloggers and fans than previously. Second, as a trend in reward consumption, consumers tended to be rewarded for their hard work to relieve and comfort their high stress caused by spending a long time worrying about the prolonged COVID-19 situation. Third, as a trend in home-economy consumption, consumers tended to prefer homewear and sportswear more because they were spending longer times at home as the social distancing period was prolonged.

첨단 헤드업 디스플레이 장치용 비구면 자유형상 금형의 초정밀 가공에 관한 연구 (A study on the ultra precision machining of free-form molds for advanced head-up display device)

  • 박영덕;장태석
    • 한국산학기술학회논문지
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    • 제20권1호
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    • pp.290-296
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    • 2019
  • 차량용 HUD는 자동차 전면 유리창에 안전 운전과 편의 운전 관련 다양한 정보를 표시해 주는 장치로 중요한 역할을 수행한다. 본 논문에서는 증강현실 기술에 적용이 가능한 대면적 비구면 자유형상 미러를 가공하기 위해 초정밀 가공기를 이용하여 가공을 실시하였고 그 결과를 측정하였다. 초정밀 다이아몬드 절삭은 정밀도가 높을 뿐만 아니라 표면 거칠기와 잔류 응력을 낮게 할 수 있어서 우수한 표면 무결성을 갖는 고급 부품의 생산에 유리하다. 또한 비구면 자유 형상의 몰드를 사용함으로써 광학 전달 함수의 개선, 왜곡 경로의 감소 및 특수 이미지 필드 곡률의 실현과 같은 장점을 얻을 수 있다. 이와 같은 비구면 자유형상 금형을 가공하기 위한 방법으로는 초정밀가공기를 이용한 다이아몬드 절삭 방법을 사용하였으며, 제작된 비구면 자유형상 미러 금형의 평가는 비구면 형상 측정기를 이용하여 실시하였다. 이러한 방법에 의해 $1{\mu}m$ 이하의 형상 정밀도(PV)와 $0.02{\mu}m$ 이하의 표면 거칠기(Ra)를 갖는 비구면 자유형상 금형을 제작할 수 있었다.

OCT4B Isoform Promotes Anchorage-Independent Growth of Glioblastoma Cells

  • Choi, Sang-Hun;Kim, Jun-Kyum;Jeon, Hee-Young;Eun, Kiyoung;Kim, Hyunggee
    • Molecules and Cells
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    • 제42권2호
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    • pp.135-142
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    • 2019
  • OCT4, also known as POU5F1 (POU domain class 5 transcription factor 1), is a transcription factor that acts as a master regulator of pluripotency in embryonic stem cells and is one of the reprogramming factors required for generating induced pluripotent stem cells. The human OCT4 encodes three isoforms, OCT4A, OCT4B, and OCT4B1, which are generated by alternative splicing. Currently, the functions and expression patterns of OCT4B remain largely unknown in malignancies, especially in human glioblastomas. Here, we demonstrated the function of OCT4B in human glioblastomas. Among the isoform of OCT4B, OCT4B-190 ($OCT4B^{19kDa}$) was highly expressed in human glioblastoma stem cells and glioblastoma cells and was mainly detected in the cytoplasm rather than the nucleus. Overexpression of $OCT4B^{19kDa}$ promoted colony formation of glioblastoma cells when grown in soft agar culture conditions. Clinical data analysis revealed that patients with gliomas that expressed OCT4B at high levels had a poorer prognosis than patients with gliomas that expressed OCT4B at low levels. Thus, $OCT4B^{19kDa}$ may play a crucial role in regulating cancer cell survival and adaption in a rigid environment.