• 제목/요약/키워드: Positive exchange bias

검색결과 13건 처리시간 0.031초

Positive Exchange Bias in Thin Film Multilayers Produced with Nano-oxide Layer

  • 전병선;황찬용
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.304-305
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    • 2013
  • We report a positive exchange bias (HE) in thinmultilayered filmscontaining nano-oxide layer. The positive HE, obtained for our system results from an antiferromagnetic coupling between the ferromagnetic (FM) CoFe and the antiferromagnetic (AFM) CoO layers, which spontaneously form on top of the nano-oxide layer (NOL). The shift in the hysteresis loop along the direction of thecooling field and the change in the sign of exchange bias are evidence of antiferromagnetic interfacial exchange coupling between the CoO and CoFe layers. Our calculation indicates that uncompensated oxygen moments in the NOL results in antiferromagnetic interfacial exchange coupling between the CoO and CoFe layers. One of the interesting features observed with our system is that it displays the positive HE even above the bulk Neel temperature (TN) of CoO. Although the positive HEsystem has a different AFM/FM interfacial spin structure compare to that of the negative HE one, the results of the angular dependence measurements show that the magnetization reversal mechanism can be considered within the framework of the coherent rotation model.

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Exchange Coupling in NiFe/Ni Bilayer Fabricated By Electrodeposition

  • Kim, D.Y.;Jeon, S.J.;Kim, K.W.;Yoon, S.S.
    • Journal of Magnetics
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    • 제16권2호
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    • pp.97-100
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    • 2011
  • Bilayers of soft NiFe (150 nm-420 nm) on hard Ni (150 nm) were prepared by electrodeposition. The process of magnetization reversal in the NiFe/Ni bilayers was then investigated. The hysteresis loop generated by a magnetization reversal of soft NiFe under a positive saturation state of a hard Ni layer shows a shift along the negative field axis, which is clear evidence for the exchange spring effect in the NiFe/Ni bilayers. The dependence of the coercive field $H_c$ and exchange bias field Hex on the thickness of the NiFe layer was also investigated. As the NiFe thickness increases from 150 nm to 420 nm, both $H_c$ and $H_{ex}$ decrease rapidly from $H_c$= 51.7 Oe and $H_{ex}$ = 12.2 Oe, and saturate to $H_c$ = 5.8 Oe and $H_{ex}$ = 3.5 Oe.

오리엔탈리즘 이전 동서문화 교류의 환경변화와 패션 (The Environmental Changes and Fashion in East-West Cultural Exchange Before Orientalism)

  • 이금희
    • 패션비즈니스
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    • 제23권1호
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    • pp.127-144
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    • 2019
  • The purpose of this study is to clarify the phenomenon and characteristics of fashion in before Orientalism by examining the environmental changes and factors of East - West cultural exchange from the 16th century to the 18th century. To this end, this study examines the development of political and diplomatic relations, the growth of economy and trade, the investment of culture and arts, and the development of industry and technology. The research method used was the analysis of previous literature research and visual data. The result were as follows; the characteristics and phenomena in fashion in before Orientalism were symbolism as a privileged whole, applying to special clothing area, variety and splendor of fabrics, change of costume design, and a trend of exotic taste. Before Orientalism, the perspective of Orient in Europe can be seen as having the positive aspects cause of developing fashion and a negative aspect coming from an incorrect understanding and a bias.

인구 집단의 스케일의 확장이 집단 비율 및 집단 크기 지각에 미치는 영향: 다수편향적 사회적 정보 활용을 중심으로 (On the Effect of Extended Human Group Scale in Perception of Group Ratio and Size at Majority-biased Social Learning)

  • 장재경 ;장대익
    • 인지과학
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    • 제34권1호
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    • pp.39-66
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    • 2023
  • 뉴미디어는 사회적 교류의 장을 인터넷으로 옮겨와 대규모 집단이 시공간의 한계를 뛰어넘어 한 곳에서 소통할 수 있게 만들었다. 최근 연구는 인간의 사회적 능력이 소셜 미디어를 통해 경험하는 확장된 집단 스케일을 따라가지 못하는 사례를 보고하기도 한다. 이러한 맥락에서, 본 연구는 인간의 사회적 정보 지각이 인구 집단 스케일의 확장에 영향을 받는지 다수편향 맥락에서 확인하였다. 인터넷 기반 과제를 통해 구성원의 수로 나타낸 집단 크기와 전체에서 특정 집단이 차지하는 집단 비율이 개인에게 지각되고 다수편향적 사회적 정보 활용에 영향을 주는 심리적 과정을 조사하였으며, 전체 집단 스케일의 확장에 각 과정이 영향을 받는지 살펴보았다. 집단 비율은 다수편향에 정적 영향을 주고 있으며, 그 관계는 비율 지각에 의해 부분매개 되었다. 전체 집단 스케일은 집단 비율과 비율 지각의 관계를 조절하지 않았다. 반면, 집단 크기와 다수편향의 상관은 유의하지 않았다. 전체 집단 스케일은 집단 크기 지각을 조절하였다. 전체 집단 스케일이 작은 조건에서 집단 크기와 크기 지각은 양적 상관을 나타냈지만, 전체 집단의 스케일이 확장된 조건에서 지각된 집단 크기는 유의미하게 작아졌고, 두 변수는 상관을 잃었다. 이러한 결과를 통해 집단 크기 지각과 관련된 심리 기제가 전체 집단 스케일의 확장에 제대로 반응하지 못하고 있음을 확인하였다. 나아가 집단 크기 정보를 처리하는 전문화된 심리 기제가 존재할 가능성과 다수편향이 특이적으로 받아들이는 자극의 형태를 진화심리적 관점에서 논하였다.

Comparison of Model-simulated Atmospheric Carbon Dioxide with GOSAT Retrievals

  • Shim, Chang-Sub;Nassar, Ray;Kim, Jhoon
    • Asian Journal of Atmospheric Environment
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    • 제5권4호
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    • pp.263-277
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    • 2011
  • Global atmospheric $CO_2$ distributions were simulated with a chemical transport model (GEOS-Chem) and compared with space-borne observations of $CO_2$ column density by GOSAT from April 2009 to January 2010. The GEOS-Chem model simulated 3-D global atmospheric $CO_2$ at $2^{\circ}{\times}2.5^{\circ}$ horizontal resolution using global $CO_2$ surface sources/sinks as well as 3-D emissions from aviation and the atmospheric oxidation of other carbon species. The seasonal cycle and spatial distribution of GEOS-Chem $CO_2$ columns were generally comparable with GOSAT columns over each continent with a systematic positive bias of ~1.0%. Data from the World Data Center for Greenhouse Gases (WDCGG) from twelve ground stations spanning $90^{\circ}S-82^{\circ}N$ were also compared with the modeled data for the period of 2004-2009 inclusive. The ground-based data show high correlations with the GEOS-Chem simulation ($0.66{\leq}R^2{\leq}0.99$) but the model data have a negative bias of ~1.0%, which is primarily due to the model initial conditions. Together these two comparisons can be used to infer that GOSAT $CO_2$ retrievals underestimate $CO_2$ column concentration by ~2.0%, as demonstrated in recent validation work using other methods. We further estimated individual source/sink contributions to the global atmospheric $CO_2$ budget and trends through 7 tagged $CO_2$ tracers (fossil fuels, ocean exchanges, biomass burning, biofuel burning, net terrestrial exchange, shipping, aviation, and CO oxidation) over 2004-2009. The global $CO_2$ trend over this period (2.1 ppmv/year) has been mainly driven by fossil fuel combustion and cement production (3.2 ppmv/year), reinforcing the fact that rigorous $CO_2$ reductions from human activities are necessary in order to stabilize atmospheric $CO_2$ levels.

변혁적 리더십 및 조직 공정성이 직무열의에 미치는 차별적 영향 : 심리적 계약위반의 매개효과 (The Differential Effects of Transformational Leadership and Organizational Justice on Work Engagement : the Mediating Role of Psychological Contract Breach)

  • 배채윤;신제구
    • 한국콘텐츠학회논문지
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    • 제17권1호
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    • pp.299-336
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    • 2017
  • 본 연구는 변혁적 리더십과 조직 공정성이 심리적 계약위반 및 직무열의에 미치는 차별적 영향을 규명하여 실무적 시사점을 제시하는데 목적이 있다. 본 연구는 직무와 조직에 공헌한 투입과 거기에서 얻은 산출의 관계를 인식하는 형평성이론, 구성원과 조직사이의 교환관계를 설명하는 사회교환이론 및 직무요구와 직무자원을 함께 보는 직무요구-자원모형을 배경으로 하였다. 제조업, 유통업, 금융업등 다양한 업종의 18개 기업의 277명을 대상으로 실증 연구를 진행하였고, 동일방법편의(common method bias) 문제점을 제거하기 위하여, 종속변수는 동료평가를 활용하여 측정하였다. 연구결과, 변혁적 리더십과 조직 공정성은 모두 구성원들의 직무 열의에 유의적인 정(+)의 영향을 미쳤고 심리적 계약위반에는 유의적인 부(-)의 영향을 미쳤다. 또한, 심리적 계약 위반은 변혁적 리더십 및 조직 공정성과 직무열의와의 관계에서 각각 부분매개역할을 하였다. 본 연구의 함의는 조직공정성이 직무열의와 심리적 계약위반에 대하여 변혁적 리더십보다 강한 영향력을 보이므로, 조직은 리더교육은 물론 공정성 확보가 필요하다는 것이다.

LC-MS/MS에 의한 벌꿀 중 잔류 네오마이신의 분석 (Analysis of residual neomycin in honey by LC-MS/MS)

  • 심영은;정지윤;명승운
    • 분석과학
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    • 제22권4호
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    • pp.319-325
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    • 2009
  • 벌꿀 중에 잔류하는 아미노그라이코사이드 항생제인 네오마이신을 효과적으로 분석하는 방법을 개발하고 방법에 대한 유효성 검증을 수행하였다. 0.1M 염산을 사용하여 벌꿀의 pH를 2로 조절한 후 고체상 추출(SPE) 고체상인 양이온교환 카트리지에 적재한 후 염기성 메탄올로 용리하였다. 용리된 추출물은 이온쌍 시약을 사용한 이온쌍 크로마토그래피법으로 분리한 후 LC/(+)ESI-MS/MS의 MRM 방법으로 분석하였다. 정량분석을 위해서 spike 한 $5.0{\sim}250{\mu}g/kg$ 농도 범위에서 검정곡선은 좋은 직선성 ($r^2$ > 0.9951)을 나타내었다. 분석방법의 상대표준편차는 11.5~18.7%이었고 정확도는 bias로 10.9~20.9%이었다. 확립된 분석방법은 벌꿀 중에서 네오마이신의 분석방법으로 유용하게 사용될 수 있을 것이다.

기부금 지출과 기업 가치: 기업지배구조를 중심으로 (Donation Expenses and Corporate Value: A Focus on the Corporate Governance Structure)

  • 김수정;강신애
    • 유통과학연구
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    • 제12권8호
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    • pp.113-121
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    • 2014
  • Purpose - Recently, the number of corporations that practice environmental and social responsibility, besides engaging in traditional profit-seeking activities, has been growing steadily, as interest in Corporate Social Responsibility (CSR) is increasing. Recent research on CSR practices has identified the relationship between CSR activities and corporate value as one of the main issues in this respect. Considering that donations constitute a large proportion of a company's charitable activities, we considered the extent of donation expenses as a charitable activity in order to mitigate sample selection bias. Specifically, we analyzed the impact of donation expenses on firm value, while investigating if this impact varied in response to the level of corporate governance of firms. Research design, data, and methodology - We used non-financial firms listed on the Korean Stock Exchange, having their fiscal year end in December, and the sample period was 2006-2013. For the dependent variable, Tobin's q was used as the corporate value, and for the independent variable, donations were measured as the donation-expense-to-sales ratio. Corporate governance scores, as rated by the Korea Corporate Governance Service, were used to measure corporate governance levels because they consider the overall aspects of governance, including ownership structure, the board of directors, and the audit mechanism of individual companies. To examine the impact of donations on a company in relation to the level of corporate governance, we estimated regression models using the interaction terms of the governance dummy and donation variables. Then, we further estimated the regression models of two sub-samples that were classified according to the level of corporate governance. Similar to previous studies, the study uses variables that affect firm value, such as R&D expenditure, advertising expenses, EBITDA, debt-to-equity ratio, sales growth, company age, and company size as control variables. Results - The empirical results show that firm value significantly increased in response to an increase in donation expenses. Upon including the interaction terms of governance level dummy variables and donations, the coefficients of the interaction terms show significant positive values, while those of donation variables show significant negative values. In the strong governance sub-sample, the relationship between the donation expenses and corporate value was statistically positive (+) and significant. However, in the weak governance sub-sample, the relationship between the donation expenses and corporate value was statistically insignificant and negative (-). Conclusions - The empirical results suggest that donation expenses are significantly linked to an enhanced corporate value if firms have a good corporate governance structure. However, if the corporate governance structure is weak, the same relationship is not necessarily observed. The results of this study show that if a firm has high corporate governance, CSR practices enhance the company's reputation such that it has a positive (+) relationship with corporate value. If a firm has weak corporate governance, on the other hand, CSR practices are recognized as an agency cost and do not increase corporate value.