• Title/Summary/Keyword: physical transition

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2D transition-metal dichalcogenide (WSe2) doping methods for hydrochloric acid

  • Nam, Hyo-Jik;Park, Jin-Hong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.291.2-291.2
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    • 2016
  • 3D semiconductor material of silicon that is used throughout the semiconductor industry currently faces a physical limitation of the development of semiconductor process technology. The research into the next generation of nano-semiconductor materials such as semiconductor properties superior to replace silicon in order to overcome the physical limitations, such as the 2-dimensional graphene material in 2D transition-metal dichalcogenide (TMD) has been researched. In particular, 2D TMD doping without severely damage of crystal structure is required different conventional methods such as ion implantation in 3D semiconductor device. Here, we study a p-type doping technique on tungsten diselenide (WSe2) for p-channel 2D transistors by adjusting the concentration of hydrochloric acid through Raman spectroscopy and electrical/optical measurements. Where the performance parameters of WSe2 - based electronic device can be properly designed or optimized. (on currents increasing and threshold voltage positive shift.) We expect that our p-doping method will make it possible to successfully integrate future layered semiconductor devices.

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The influence of parental strain on the marital adjustment of employed mothers after transition to the parenthood and the buffering effect of social support (부모역할 전환 후 부모로서의 긴장감이 취업모의 결혼적응에 미치는 영향과 사회적 지지의 완충효과에 관한 연구)

  • Koh, Seon-Ju
    • Korean Journal of Human Ecology
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    • v.13 no.5
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    • pp.637-646
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    • 2004
  • The purpose of this study is to examine the relation between parental strain and marital adjustment of employed mothers after their transition to the parenthood, and to investigate buffering effect of social support on the relation. The parental strain variables (physical strain and emotional strain) appear to be significant predictors of marital adjustment for employed mothers with first baby. The analysis on interaction effect indicates that social support can be a positive buffering indicator. A comparison reveals that mothers with high physical strain have significantly higher marital adjustment than those with low strain. But in the context of high social support, the difference of marital adjustment between the two mothers is reduced.

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Parental strain, mastery, sex role attitude, and dyadic adjustment after the transition to parenthood in the dual earner family (취업부부의 부모기 전이후 부모로서의 긴장감, 지배감, 성역할태도와 결혼적응)

  • 고선주
    • Journal of the Korean Home Economics Association
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    • v.35 no.5
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    • pp.17-32
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    • 1997
  • The purpose of this study is to explore parental strain, mastery, sex role attitude and dyadic adjustment after the transition to parenthood in dual earner family. Using couple data from a sample of 284 dual earner couple, pair t-test, multiple regression analysis, one was ANOVA was used. Major findings were as follows. 1) There were differences between wives and husbands in dyadic adjustment, physical strain, mastery, sex role attitude. Specially, couples experience more emotional strain than physical strain, and wives experience more parental strain than husbands. 2) Couple's parental strain is considered personal attribution rather than family one, but mastery is different. 3) Couple's psychological variables have an effect on the dyadic adjustment sores, especially husband's sex role attitude influences own dyadic adjustment and wife's dyadic adjustment. Wife's mastery also own dyadic adjustment and husband's dyadic adujstment.

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Generation of Maxwell Displacement Current Across Single monolayers due to Phase transition

  • Mitsumasa Iwamoto;Wu, Chen-Xu
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.05a
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    • pp.6.1-10
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    • 1996
  • Starting from the Debye theory of rotational Brownian motion equation, we derive an expression for explaining the generation of Maxwell displacement current (MDC) across single monolayers on a material surface. The orientational order parameter and the dielectric relaxation the of monolayers are derived. Based on fille analyses developed here, we examine the MDC across phospholipid monolayers with thermal stimulation due to the change in the spontaneous polarization, and the generation of MDC from 4-cyano-4\`-5-alkayl-biphenyl(5CB) Langmuir-film at the onset of transition by monolayer compression

Transition Program for Youth With Disabilities: Research Trend Analysis and Systematic Review (장애청소년의 전환프로그램 : 연구 동향 분석과 체계적 고찰)

  • An, Su-bin;Park, Hae Yean
    • Therapeutic Science for Rehabilitation
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    • v.11 no.3
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    • pp.23-36
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    • 2022
  • Objectives : This study aimed to provide basic data on intervention strategies that occupational therapists can access by systematically analyzing the intervention and effectiveness for youth with disabilities. Methods : The RISS, PubMed, and Web of Science databases were used to search for papers published between 2006 and 2021. The keywords were "Disability AND Adolescents OR Young adult AND Transition education OR Transition program". Seven papers were selected for analysis, and the full text was reviewed. The keywords and national relations were analyzed and visualized using the WoS (Web of Science) and VOSviewer programs. Results : The participants were classified into five types (ASD or ADHD, ID, DD, and physical disability). The areas used for the intervention were mixed into three categories: occupation (academic), self-management (time), and interaction (personal relations and communication). Sociality and adaptation, quality of life, and at least one of the three categories of daily life activities showed significant improvement. Conclusions : This study can be used as basic data to expand the area where only OTs can contribute while grasping the research trend of the conversion program and presenting the direction of exchange with various experts by organizing the application and its effects.

Tunable Metal-Insulator Phase Transition in $VO_2$ Nanowires

  • Seong, Won-Kyung;Lee, Ji-Yeong;Moon, Myoung-Woon;Lee, Kwang-Ryeol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.385-385
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    • 2012
  • Understanding the thermodynamics and structural transformation during the Metal-Insulator Transition (MIT) is critical to better understand the underlying physical origin of phase transition in the vanadiumdioxide ($VO_2$). Here, through the temperature-dependent in-situ high resolutiontransmission electron microscopy (HR-TEM), and systematic electrical transport study, we have shown that the tunable MIT transition of $VO_2$ nanowires is strongly affected by interplay between strain and domain nucleation by ion beam irradiation. Surprsingly, we have also observed that the $VO_2$ rutile (R) metallic phase could form directly in a strain-induced metastable monoclinic (M2) phase. These insights open the door toward more systematic approaches to synthesis for $VO_2$ nanostructures in desired phase and to use for applications including ultrafast optical switching, smart window, metamaterial, resistance RAM and synapse devices.

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Bonding And Anti-bonding Nature of Magnetic Semiconductor Thin Film of Fe(TCNQ:tetracyanoquinodimethane)

  • Jo, Junhyeon;Jin, Mi-jin;Park, Jungmin;Modepalli, Vijayakumar;Yoo, Jung-Woo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.294-294
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    • 2014
  • Developing magnetic thin films with desirable physical properties is a key step to promote research in spintronics. Organic-based magnetic material is a relatively new kind of materials which has magnetic properties in a molecular and microscopic level. These materials have been constructed by the coordination between 3d transition metal and organic materials producing long-range magnetic orders with a relatively high transition temperature. However, these materials were mostly synthesized as a form of powder, which is difficult to study for their physical properties as well as apply for electronic/spintronic devices. In this study, we have employed physical vapor deposition (PVD) to develop a new organic-based hybrid magnetic film that is achieved by the coordination of Fe and tetracyanoquinodimethane (TCNQ). The IR spectra of the grown film show modified CN vibration modes in TCNQ, which suggest a strong bonding between Fe and TCNQ. The thin film has both ferromagnetic and semiconducting behaviors, which is suitable for molecular spintronic applications. The high resolution photoemission (HRPES) spectra also show shift of 1s peak point of nitrogen and the carbon 1s peaks display traces of charge transfer from Fe to TCNQ as well as shake-up features, which suggest strong bonding and anti-bonding nature of coordination between Fe and TCNQ.

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The characteristics of nonlinear magneto-optical effect based on coherent population trapping in the D1 line of Rh atoms (87Rb D1 전이선에서 원자결맞음을 이용한 비선형 광자기 효과 신호의 특성)

  • Lee, L.;Moon, H.S.;Kim, J.B.
    • Korean Journal of Optics and Photonics
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    • v.17 no.1
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    • pp.1-6
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    • 2006
  • We investigated the characteristics of the nonlinear magneto-optic effect (NMOE) depend on the transitions, the laser intensity and the temperature of the vapor cell, in the $D_1$ transition of $^{87}Rb$ atoms by using the Rb vapor cell contained with buffer gas of Ne 6.7 kPa. The size and the width of NMOE signal were increased according to the light intensity and temperature in the transition of F=2$\to$F'=2. However, In the case of using the F=2$\to$F'=1 transition, the size of the signal could be increased according to the light intensity without additional broadening of the width. We confirmed that the sensitivity of detecting small magnetic flux improved in this transition, and explained these effects by the different of the CPT configuration between Zeeman sublevels. At the optimal condition in experiment, the sensitivity of this system was evaluated less then $70pT/\sqrt{Hz}$.

Non-stoichiometry-induced metal-to-insulator transition in nickelate thin films grown by pulsed laser deposition

  • Lee, Jongmin;Choi, Kyoung Soon;Lee, Tae Kwon;Jeong, Il-Seok;Kim, Sangmo;Song, Jaesun;Bark, Chung Wung;Lee, Joo-Hyoung;Jung, Jong Hoon;Lee, Jouhahn;Kim, Tae Heon;Lee, Sanghan
    • Current Applied Physics
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    • v.18 no.12
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    • pp.1577-1582
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    • 2018
  • While controlling the cation contents in perovskite rare-earth nickelate thin films, a metal-to-insulator phase transition is reported. Systematic control of cation stoichiometry has been achieved by manipulating the irradiation of excimer laser in pulsed laser deposition. Two rare-earth nickelate bilayer thin-film heterostructures with the controlled cation stoichiometry (i.e. stoichiometric and Ni-excessive) have been fabricated. It is found that the Ni-excessive nickelate film is structurally less dense than the stoichiometric film, albeit both of them are epitaxial and coherent with respect to the underlying substrate. More interestingly, as a temperature decreases, a metal-to-insulator transition is only observed in the Ni-excessive nickelate films, which can be associated with the enhanced disproportionation of the Ni charge valence. Based on our theoretical results, possible origins (e.g. anti-site defects) of the low-temperature insulating state are discussed with the need of future work for deeper understanding. Our work can be utilized to realize unusual physical phenomena (e.g. metal-to-insulator phase transitions) in complex oxide films by manipulating the chemical stoichiometry in pulsed laser deposition.