• Title/Summary/Keyword: Polarization Condition

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Novel Polarization Condition of Optical Polarized Beamsplitter with Misaligned Input Interface and Guiding Loss (불연속 입력 경계면과 전송 손실이 있는 광 편파기 설계를 위한 새로운 편파조건)

  • Ho, Kwang-Chun
    • Journal of IKEEE
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    • v.11 no.1 s.20
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    • pp.61-68
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    • 2007
  • Using modal transmission-line theory (MTLT), itexplores rigorously the polarization characteristics of TE-TM mode optical polarized beamsplitter with misaligned input interface. To verify the validity of the approach proposed in this paper, a novel polarization condition is defined, and it compares and evaluates with the polarization condition of coupled-mode theory (CMT) used widely. The numerical results reveal that the discontinuity of misaligned input interface has nothing to do with the polarization condition of beamsplitter. Furthermore, the condition of CMT is no longer effective at the asymmetric guiding structures with strong power coupling.

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A Study of Factors Affecting Group Polarization in Online Communication : Based on Anonymity (온라인 커뮤니케이션에서 집단극화 현상에 영향을 미치는 요인에 관한 연구: 익명성 관점에서)

  • Suh, Eung-Kyo
    • Journal of Distribution Science
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    • v.13 no.2
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    • pp.75-83
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    • 2015
  • Purpose - This study aims to identify the effects of communication cues, anonymity, and social presence on group polarization in computer-mediated communication (CMC) settings. Extant literature has introduced some theoretical backgrounds of social presence and SIDE (Social Identity model of Deindividuation Effects) to explain the effects of communication cues and anonymity. The concept of social presence emphasized the mediating role on communication cues and anonymity. However, most literature did not measure social presence and compare group polarization of all condition groups. This does not sufficiently explain the result of group polarization. Research design, data, and methodology - We believe that the direct impact of anonymity on group polarization can provide a more admissible and clearer explanation for the results. In addition, this study categorizes anonymity into two levels, as anonymity of group and anonymity of self. To justify the anonymity view, a laboratory experiment was conducted. The experiment was conducted in communication cues settings (visual cue; without visual cue) and anonymity settings (identified; anonymous). Each of the four settings has 10 groups consisting of five subjects each (total 200 subjects). The subjects are undergraduates from a large university, majoring in business. All experimental procedures and calculations of choice shift and preference change follow the literature. Results - First, the removal of visual cues does not produce a significant impact on group polarization, which cannot be explained by the social presence view. Second, the anonymous condition does not significantly affect group polarization, which also cannot be explained by the social presence view. However, the anonymous condition directly affects group polarization. Specifically, anonymity of self has a stronger effect on group polarization than anonymity of group. The result explains about the leading factor affecting group polarization. This study examines another view of how computer-mediated communication may be associated with group polarization. The process and outcome data from the experiment reveal that group polarization is not affected by level of social presence, but by level of anonymity. Group discussions conducted with visual cue CMC setting and identified CMC setting result in weaker group polarization. Conversely, group discussions conducted without visual cue CMC setting and anonymous CMC setting lead to stronger group polarization. The results of the study have the following implications. First, they provide clues for business organizations to design the most appropriate media conditions and preemptive social conditions to implement when making group decisions through CMC, to maximize achievements, generate amicable agreements, or actively share information. Second, this study can be useful in analyzing different adverse effects generated through Internet use. Conclusions - This research can help explain discussions and decision-making actions on Internet forums, which have recently increased, as well as providing a foundational basis in newly establishing policies for the forums. Finally, it should be noted that many other factors such as group size, topics, and group history may affect group polarization. These should be examined in future studies.

The research for the enhancement of depth of focus by elliptical polarization illumination(EPI) (타원편광 조명에 의한 초점심도 향상에 관한 연구)

  • 박정보;김기호;이성묵
    • Korean Journal of Optics and Photonics
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    • v.9 no.3
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    • pp.146-150
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    • 1998
  • To enhance the resolution and the depth of focus of the patterns whose size reaches the optical resolution limits, the various imaging methods are being tried. Generally in the linear polarization illumination methods, the contrast gap exists between TE mode TM mode according to the pattern direction. However, through the previous research, the elliptical polarization illumination(EPI) method was proposed to overcome this contrast gap. In this research, we investigated the optimal polarization condition to be able to enhance the depth of focus(DOF) for the optional mask which is containing the opposite direction patterns by applying the various polarization conditions including EPI. The DOF according to each polarization condition was obtained by ED-Tree(Exposure-Defocus Tree) for the given exposure dose and CD error boundaries. As the result, we can ascertain th effect of EPI for the enhancement of DOF in some condition of optical system.

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Effect of Humidity on the Hydrogen Embrittlement of STS 444 Weld Zone for Boiler (보일러용 STS 444재 용접부의 수소취성에 미치는습기의 영향)

  • LIM, Uh-Joh;Choe, Byung-il;Yun, Byoung-Du
    • Journal of Fisheries and Marine Sciences Education
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    • v.18 no.1
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    • pp.58-64
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    • 2006
  • In order to examine the effect of humidity on hydrogen embrittlement of STS 444 weld zone for boiler with dry and wet welding conditions, this paper was carried out the accelerated hydrogen osmosis test and the electrochemical Tafel polarization test. In 0.5M $H_2SO_4$ + 0.01M $As_20_3$ solution, this test is added to load of $1400kg/cm^2$ together with hydrogen osmosis by current of $50 {mA/cm^2}$ for 60 min.. The electrochemical Tafel polarization test was carried out in 0.5M $H_2SO_4$ + 0.01M $As_20_3$ solution. Therefore, the effect of humidity on hydrogen embrittlement of STS 444 was considered. The main results are as following: On the basis of hydrogen embrittlement mechanism, that is, integrated electrochemical polarization characteristics with the established mechanism of hydrogen embrittlement, the reduction rate of corrosion current density of weld zone in the wet weld condition is larger than in the dry condition. We can nondestructively predict the degree of hydrogen embrittlement of STS 444 weld zone for boiler through the reduction rate of electrochemical corrosion current density.

Micro Electrochemical Machining using Anodic Polarization Curve (양극분극곡선을 미용한 미세 전해가공)

  • 최영수;강성일;전종업;박규열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.999-1002
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    • 2002
  • In this research, the mechanism of micro-ECM was investigated with potentiodynamic method and the optimal condition for micro-ECM was selected by voltage-current-time curve with potentiostatic method. From the experimental result. it was confirmed that anodic voltage curve could be used very effectively for determining the optimal condition of micro-ECM, and the micro part which has extremely fine surface could be fabricated by use of micro-ECM with point electrode method.

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Corrosion Evaluation of Epoxy-Coated Bars in Chloride Contaminated Concrete Using Linear Polarization Tests

  • Choi, Oan-Chul;Jung, Si-Young;Park, Young-Soo
    • International Journal of Concrete Structures and Materials
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    • v.18 no.1E
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    • pp.3-9
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    • 2006
  • Five slab specimens with predefined cracks are examined to evaluate the corrosion behavior of epoxy-coated bars in chloride contaminated concrete, using linear polarization method. The test specimens were subjected to alternating weekly cycles of ponding in a salt solution and drying for 48 weeks. Test results show that the current density of the specimen of normal steel bars becomes 0.715 ${\mu}A/cm^2$ indicating that the steel bars are in moderate or high corrosion condition. However, the corrosion rates of the specimens with damaged epoxy-coated bars are significantly below 0.1 ${\mu}A/cm^2$ and the bars appears to be in passive condition. The damaged epoxy-coated bars with a corrosion inhibitor of calcium nitrite showed a corrosion rate of 0.110 ${\mu}m/year$ or 56 percents of the corrosion rate of damaged epoxy-coated specimen without such an inhibitor, 0.195 ${\mu}m/year$. However, the corrosion rates of specimens containing the other two corrosion inhibitors, a combination of amines and esters or mixtures of organic alkenyl dicarboxyl acid salts are quite equivalent to the control specimen. The research technique of linear polarization resistance method has proven itself to be useful in measuring corrosion rates of reinforcement in concrete.

Improvement of Chemical Mechanical Polishing (CMP) Performance of Nickel by Additions of Abrasive and Various Oxidizers (산화제 및 연마제 첨가를 통한 Nickel CMP 특성 개선 연구)

  • Choi, Gwon-Woo;Kim, Nam-Hoon;Seo, Yong-Jin;Lee, Woo-Sun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.7
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    • pp.605-609
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    • 2005
  • Chemical mechanical polishing (CMP) of Ni was performed by the various ratios of four kinds of oxidizers and an addition of alumina powders as an abrasive in each slurry with the different oxidizers. Moreover, the interaction between the Ni and the each oxidizer was discussed by potentiodynamic polarization measurement, in order to compare the effects of Ni-CMP and electrochemical characteristics on the Ni with the different oxidizers. As an experimental result, the removal rate of Ni reached a maximum at 1 $vol\%$ of $H_2O_2$. Also the removal rates of Ni increased with the audition of alumina abrasives in each slurry. The potentiodynamic polarization of Ni under dynamic condition showed a significant difference in electrochemical behavior by addition of $H_2O_2$ in solutions. Ni showed the perfect passivation behavior in solution without $H_2O_2$ under potentiodynamic polarization condition, while active dissolution dominates in solution with the addition of $H_2O_2$. The results indicate that the surface chemistry and electrochemical characteristics of Ni play an important role in controlling the polishing behavior of Ni.

Comparative Study on Conductivity and Moisture Content Using Polarization and Depolarization Current (PDC) Test for HV Insulation

  • Jamail, N.A.M.;Piah, M.A.M.;Muhamad, N.A.;Kamarudin, Q.E.
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.1
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    • pp.7-11
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    • 2014
  • The Polarization and Depolarization Current (PDC) measurement is an efficient and effective diagnostic technique based on time domain measurement, for evaluating the high voltage insulation condition. This paper presents a review and comparison results from several published papers on the application of the PDC method to finding the conductivity and moisture content of various types of insulators. For solid insulation, the study was focused on cable insulation, electric machine stator insulation, and paper insulator in transformer insulation with different conditions. For liquid insulation, the review and comparison was done on biodegradable and mineral transformer oils, with fresh oil condition, and aged condition. The results from previous researchers tests were complied, analyzed and discussed, to evaluate the application of the PDC method to monitor the conductivity and moisture of HV equipment insulation systems. From the review results, the PDC technique successfully gives an indication of the conductivity and moisture level of high voltage insulation.

Implementation of Nano-Scale Grating-Assisted Coupler with Polarization-Insensitivity using Double-Sandwiched Guide (이중 샌드위치 도파로를 사용한 편광 무의존성 특성을 갖는 나노크기 격자 구조형 결합기의 구현)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.2
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    • pp.221-227
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    • 2015
  • The polarization characteristics of nano-scale grating-assisted polarization-insensitive coupler (GA-PIC) consisted of double sandwiched rib-type layers are evaluated in detail by using modal transmission-line theory (MTLT) based on equivalent network. To obtain the polarization-insensitive condition of GA-PIC, the coupling lengths as a function of the refractive index and thickness of sandwiched rib-type layer as well as the grating thickness and period are analyzed for quasi-TE and quasi-TM modes. The numerical results show that the GA-PIC with hundreds of nanometer scale is realized by properly choosing structural and material parameters of double sandwiched layers and grating.