• Title/Summary/Keyword: Positive exchange bias

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

  • Jeon, Byeong-Seon;Hwang, Chan-Yong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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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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    • v.16 no.2
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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.

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

  • Lee, Keum Hee
    • Journal of Fashion Business
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    • v.23 no.1
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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.

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

  • Jaekyung Jang;Dayk Jang
    • Korean Journal of Cognitive Science
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    • v.34 no.1
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    • pp.39-66
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    • 2023
  • New media moved the place of social exchange to the Internet, allowing large groups to communicate in one place beyond the limits of time and space. Recent studies have also reported cases in which human social abilities do not keep up with the expansion of group scale through social media. In this context, current study investigated how human perception of social information is affected by the expansion of the group scale in the context of majority bias. Using Internet-based task, the psychological processes that group ratio and group size are perceived and affect majority-biased social information use were investigated, and whether group scale moderates those processes was examined. The group ratio has a positive effect on the majority bias, and the relationship was partially mediated by ratio perception. Group scale did not moderate the relationship between group ratio and ratio perception. On the other hand, the correlation between group size and majority-biased social information use was not significant. Group scale moderates group size perception. The group size and size perception showed positive correlation under the smaller group scale condition. However under the extended group scale condition, the perceived group size became significantly lower and lost its correlation with group size. These results provide evidence that the psychological mechanism related to group size perception was not properly responding to the expansion of the group scale. Furthermore, the possibility of a specific psychological mechanism for processing group size information and the form of information input specifically accepted by majority bias were discussed from perspective of evolutionary psychology.

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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    • v.5 no.4
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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.

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

  • Baec, Chae-Yoon;Shin, Je-Goo
    • The Journal of the Korea Contents Association
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    • v.17 no.1
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    • pp.299-336
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    • 2017
  • The purpose of this study is to identify the differential effects of transformational leadership and organizational justice on psychological contract breach and work engagement, and to suggest practical implications. To this purpose, this study theoretically references equity theory which recognizes the relationship between organizational input and output, social exchange theory which explains the exchange relationship between members and organization, and job demand-resource (JD-R) model that combines job demands and job resources. A empirical study was conducted on 277 employees at 18 companies of diverse industries including manufacturing, distribution, and finance, and to eliminate the common method bias problem, the dependent variable was measured using peer evaluation. The results of this study showed that: 1) both transformational leadership and organizational justice had a significant positive effect on work engagement and significant negative effect on psychological contract breach; and 2) psychological contract breach played a partial mediating role in the relationship between transformational leadership and work engagement as well as between organizational justice and work engagement. Therefore, this study suggests that, as organizational justice has stronger influence on work engagement and psychological contract breach than transformational leadership, organizations should not only train its leaders but also guarantee fairness.

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

  • Shim, Young-Eun;Jeong, Ji-Yoon;Myung, Seung-Woon
    • Analytical Science and Technology
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    • v.22 no.4
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    • pp.319-325
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    • 2009
  • An effective and specific procedure for confirmation of neomycin, aminoglycoside antibiotic in honey was developed and validated. Honey was adjusted to pH 2 with 0.1M HCl and applied to weak cation-exchange SPE cartridge. Neomycin was eluted with basified methanol. Following separation by ion-pairing liquid chromatography, neomycin was analysed with positive electrospray ionization and MRM mode. Quantification was linear over the range of $5.0{\sim}250.0{\mu}g/kg$ ($r^2$ >0.9951). The precision (R.S.D.) and accuracy (as a bias) of quality control samples in honey ranged 11.5~18.7% and 10.9~20.9%, respectively. Established method can be applied to analysis of neomycin in honey.

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

  • Kim, Soo-Jung;Kang, Shin-Ae
    • Journal of Distribution Science
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    • v.12 no.8
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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.