• Title/Summary/Keyword: Amorphous solid

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A Study on the characteristics of polycrystalline silicon thin films prepared by solid phase cyrstallization (고상 결정화에 의해 제작된 다결정 실리콘 박막의 특성 연구)

  • 김용상
    • Electrical & Electronic Materials
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    • v.10 no.8
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    • pp.794-799
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    • 1997
  • Poly-Si films have been prepared by solid phase crystallization of LPCVD(low-pressure CVD) amorphous silicon. The crystallinity of poly-Si films has been derived from UV reflectance spectrum and lies in the range between 70% and 80% . From XRD measurement the peak at 28.2$^{\circ}$from (111) plane is dominantly detected in the SPC poly-Si films, The average grain size of poly-Si film is determined by the image of SEM and varies from 4000 $\AA$ to 8000$\AA$. The electrical conductivity of as-deposited amorphous silicon film is about 2.5$\times$10$^{-7}$ ($\Omega$.cm)$^{-1}$ , and 3~4$\times$10$^{-6}$ ($\Omega$.cm)$^{-1}$ of room temperature conductivity is the SPC poly-Si films. The conductivity activation energies are 0.5~0.6 eV or the 500$\AA$-thick poly-Si films.

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Development of High-Performance LNMO Based Thin-Film Battery through Amorphous V2O5 Interlayer Insertion (비정질 V2O5 중간층 삽입을 통한 고성능 LNMO기반 박막 배터리 개발)

  • Kwon, Oh Hyuk;Kim, Jong Heon;Park, Jun Seob;Kim, Hyun-Suk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.2
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    • pp.194-198
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    • 2022
  • All-solid-state thin-film battery can realize the integration of electronic circuits into small devices. However, a high voltage cathode material is required to compensate for the low energy density. Therefore, it is necessary to study all-solid-state thin-film battery based on the high voltage cathode material LNMO. Nevertheless, the electrochemical properties deteriorate due to the problem of the interface between LiNi0.5Mn1.5O4 (LNMO) and the solid electrolyte LiPON. In this study, to solve this problem, amorphous V2O5 was deposited as an interlayer between LNMO and LiPON. We confirmed the possibility of improving cycle performance of LNMO based thin-film battery. We expect that the results of this study can extend the battery lifespan of small devices using LNMO based all-solid-state thin-film battery.

Comparison and Characterization of Silodosin-loaded Solid Dispersions Prepared by Various Solid Dispersion Preparation Methods (다양한 고체분산체 제조방법으로 제조한 실로도신 함유 고체분산체의 비교 및 특성분석)

  • Su Man Lee;Da Young Song;Kyeong Soo Kim
    • Journal of Powder Materials
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    • v.31 no.3
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    • pp.263-271
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    • 2024
  • This study focused on improving the solubility of silodosin, a drug poorly soluble in water, by utilizing solid dispersions. Three types of dispersions were examined and compared against the drug powder: surface-attached (SA), solvent-wetted (SW), and solvent-evaporated (SE). Polyvinyl alcohol (PVA) was identified as the most effective polymer in enhancing solubility. These dispersions were prepared using spray-drying techniques with silodosin and PVA as the polymer, employing solvents such as water, ethanol, and a water-acetone mix. The physicochemical properties and solubility of the dispersions were evaluated. The surface-attached dispersions featured the polymer on a crystalline drug surface, the solvent-wetted dispersions had the amorphous drug on the polymer, and the solvent-evaporated dispersions produced nearly round particles with both components amorphous. Testing revealed that the order of improved solubility was: solvent-evaporated, solvent-wetted, and surface-attached. The results demonstrated that the preparation method of the solid dispersions significantly impacted their physicochemical properties and solubility enhancement.

Crystallization Mechanisms of Joule-Heating-Induced Crystallization

  • Park, Doo-Jung;Ro, Jae-Sang
    • Journal of Information Display
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    • v.10 no.2
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    • pp.76-79
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    • 2009
  • In Joule-heating-induced crystallization, solid-to-solid or liquid-to-solid phase transformation could occur. It was found that novel physical phenomena that randomly nucleated liquid seeds, followed by rapid solidification in an amorphous matrix, during the Joule-heating-up period play an important role especially in liquid-to-solid transformation. Under some processing conditions, super-grains sized 6-8 ${\um}m$ were produced by the lateral growth from the initial seeds, without any artificially control.

Understanding the Plasticity of Amorphous Alloys Via the Interpretation of Structural Evolution Inside a Shear Band (비정질 합금의 전단띠 내부 구조변화 해석을 통한 소성의 이해)

  • Lee, Chang-Myeon;Park, Kyoung-Won;Lee, Byeong-Joo;Shim, Jae-Hyeok;Lee, Jae-Chul
    • Korean Journal of Materials Research
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    • v.19 no.5
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    • pp.276-280
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    • 2009
  • The effect of the initial packing structure on the plasticity of amorphous alloys was investigated by tracing the structural evolution of the amorphous solid inside a shear band. According to the molecular dynamics simulations, the structural evolution of the amorphous solids inside the shear band was more abrupt in the alloy with a higher initial packing density. Such a difference in the structural evolution within the shear band observed from the amorphous alloys with different initial packing density is believed to cause different degrees of shear localization, providing an answer to the fundamental question of why amorphous alloys show different plasticity. We clarify the structural origin of the plasticity of bulk amorphous alloys by exploring the microstructural aspects in view of the structural disordering, disorder-induced softening, and shear localization using molecular dynamics simulations based on the recently developed MEAM (modified embedded atom method) potential.