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Browsing by Author Phung, Quoc Bao

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Showing results 1 to 8 of 8
  • Alkali metal-substituted bismuth-based perovskite compounds_ A DFT study.pdf.jpg
  • Article

  • Alkali metal-substituted bismuth-based perovskite compounds: A DFT study

    • Authors: Nguyen, Hoang Linh; Nguyen, Hoang Tuan; Dang, Duc Dung; Phung, Quoc Bao; Bach, Thanh Cong; Le, Thi Hai Thanh (2019)

  • In this study, we have performed density functional theory based calculations to investigate the effect of alkali substituents M on the structure and electronic properties of (Bi0.5M0.5)TiO3 compounds with M ¼ Li, Na and K. When the ionic radius of the substituting M cation increases, the corresponding direct band gap of (Bi0.5M0.5)TiO3 also increases. The same trend is found for the O-deficient Bi0.5M0.5TiO3- d compounds, which were investigated by removing one Oxygen atom from the super cell creating an Ovacancy in it. The presence of the O-vacancy breaks the local symmetry of the crystal structures and generates excess electrons in the O-deficient compounds. This results in t...
  • 233.pdf.jpg
  • Article

  • A black-box model of optical amplifier chains in optical fibre telecommunications systems

    • Authors: Nguyen, Tuan Anh; Phung, Quoc Bao (2003)

  • A simple model is proposed to evaluate the number of amplifiers and the required power in optical fibre transmission systems using a chain of EDFA. The model requires only knowledge of the overall gain of the amplifier chain, the noise figure and the amplifier spacing beside the line's parameters. The influence of attenuation and dispersion of the fiber cable are also taken into account.
  • 114.pdf.jpg
  • Article

  • Growth of CdS thin films by chemical bath deposition technique

    • Authors: Be, Xuan Hop; Ha, Van Trinh; Khuc, Quang Dat; Phung, Quoc Bao (2008)

  • The structural, morphological and optical properties of CBD deposited CdS thin films have been studied by varying the processing parameters and the Cd/S ratio of the starting precursors in order to better understand the growth conditions. The films were characterized by X-ry diffration, SEM, Raman, and photoluminescence spectroscopy. SRD patterns show that asdeposited CdS films were polycrystalline. The fact that the symmetry - dependent Raman bands of the CdS thin films under investigation did not appear indicates the poor preferential orientation of as-deposited CdS crystallites, which is in accordance with the measured XRD pattern.
  • 112.pdf.jpg
  • Article

  • Multi-channel measurement based on DSP development

    • Authors: Nguyen, Tuan Anh; Nguyen, Xuan Thai; Phung, Quoc Bao; Bach, Gia Duong (2010)

  • A real-time and simultaneous processing system with 8 analog inputs is designed. The system is based on the development of Texas Instrument TMS320VC5510 DSK kit. The analog input signals are converted into digital ones by 8 bit ADC module using ADC0809. The ADC module interfaces to the DSP in parallel, through the DSP's Memory Expansion Connector. The measurement with standard input signals fom FUNCTION GENERATOR LG1311 is also reported.
  • 239.pdf.jpg
  • Article

  • Simulation of Optical Fiber Communications Systems Using EDFA

    • Authors: Nguyen, Tuan Anh; Phung, Quoc Bao (2003)

  • EDFA's technical parameters and the influence of fiber cable attenuation, of fiber cable dispersion are evaluated to meet optical transmission system's requirements. The type and the number of EDFA are optimized. The maximal length of the communications line is also calculated.
  • 243.pdf.jpg
  • Article

  • Sol-Gel Deposition of ZnO:Al Thin Films

    • Authors: Phung, Quoc Bao; Khuc, Quang Dat; Nguyen, Trong Nghia (2003)

  • Singlelayer aluminium-doped zinc oxide films were prepared on silicium substrates by the sol-gel spin coating process. The As-deposited films have been characterized by X-ray diffration (XRD) and optical spectroscopy. All samples were polycrystalline with the hexagonal structure and the prefered texture.
  • 216.pdf.jpg
  • Article

  • Sol-gel spin-coating preparation of Zno:In films with highly C-axis orientation

    • Authors: Phung, Quoc Bao; Khuc, Quang Dat; Nguyen, Thien Huong (2004)

  • The c-axis oriented ZnO:In films were prepared by the sol-gel spin-coating process using zinc acetate 2-hydrate, ethylene glycol, indium nitrate 9-hydrate, triethylamine as starting materials. The preferred orientation of the films increased with heat treatment temperature. Near u v and green photoluminescent emisions from the films was observed at room temperature. The PL intensity was found to be greatly dependent on post-deposition heat treatment. Influence of the multilayer deposition on XRD analysis and PL characterisation was also discussed.

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Browsing by Author Phung, Quoc Bao

Jump to: 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
or enter first few letters:  
Showing results 1 to 8 of 8
  • Alkali metal-substituted bismuth-based perovskite compounds_ A DFT study.pdf.jpg
  • Article

  • Alkali metal-substituted bismuth-based perovskite compounds: A DFT study

    • Authors: Nguyen, Hoang Linh; Nguyen, Hoang Tuan; Dang, Duc Dung; Phung, Quoc Bao; Bach, Thanh Cong; Le, Thi Hai Thanh (2019)

  • In this study, we have performed density functional theory based calculations to investigate the effect of alkali substituents M on the structure and electronic properties of (Bi0.5M0.5)TiO3 compounds with M ¼ Li, Na and K. When the ionic radius of the substituting M cation increases, the corresponding direct band gap of (Bi0.5M0.5)TiO3 also increases. The same trend is found for the O-deficient Bi0.5M0.5TiO3- d compounds, which were investigated by removing one Oxygen atom from the super cell creating an Ovacancy in it. The presence of the O-vacancy breaks the local symmetry of the crystal structures and generates excess electrons in the O-deficient compounds. This results in t...
  • 233.pdf.jpg
  • Article

  • A black-box model of optical amplifier chains in optical fibre telecommunications systems

    • Authors: Nguyen, Tuan Anh; Phung, Quoc Bao (2003)

  • A simple model is proposed to evaluate the number of amplifiers and the required power in optical fibre transmission systems using a chain of EDFA. The model requires only knowledge of the overall gain of the amplifier chain, the noise figure and the amplifier spacing beside the line's parameters. The influence of attenuation and dispersion of the fiber cable are also taken into account.
  • 114.pdf.jpg
  • Article

  • Growth of CdS thin films by chemical bath deposition technique

    • Authors: Be, Xuan Hop; Ha, Van Trinh; Khuc, Quang Dat; Phung, Quoc Bao (2008)

  • The structural, morphological and optical properties of CBD deposited CdS thin films have been studied by varying the processing parameters and the Cd/S ratio of the starting precursors in order to better understand the growth conditions. The films were characterized by X-ry diffration, SEM, Raman, and photoluminescence spectroscopy. SRD patterns show that asdeposited CdS films were polycrystalline. The fact that the symmetry - dependent Raman bands of the CdS thin films under investigation did not appear indicates the poor preferential orientation of as-deposited CdS crystallites, which is in accordance with the measured XRD pattern.
  • 112.pdf.jpg
  • Article

  • Multi-channel measurement based on DSP development

    • Authors: Nguyen, Tuan Anh; Nguyen, Xuan Thai; Phung, Quoc Bao; Bach, Gia Duong (2010)

  • A real-time and simultaneous processing system with 8 analog inputs is designed. The system is based on the development of Texas Instrument TMS320VC5510 DSK kit. The analog input signals are converted into digital ones by 8 bit ADC module using ADC0809. The ADC module interfaces to the DSP in parallel, through the DSP's Memory Expansion Connector. The measurement with standard input signals fom FUNCTION GENERATOR LG1311 is also reported.
  • 239.pdf.jpg
  • Article

  • Simulation of Optical Fiber Communications Systems Using EDFA

    • Authors: Nguyen, Tuan Anh; Phung, Quoc Bao (2003)

  • EDFA's technical parameters and the influence of fiber cable attenuation, of fiber cable dispersion are evaluated to meet optical transmission system's requirements. The type and the number of EDFA are optimized. The maximal length of the communications line is also calculated.
  • 243.pdf.jpg
  • Article

  • Sol-Gel Deposition of ZnO:Al Thin Films

    • Authors: Phung, Quoc Bao; Khuc, Quang Dat; Nguyen, Trong Nghia (2003)

  • Singlelayer aluminium-doped zinc oxide films were prepared on silicium substrates by the sol-gel spin coating process. The As-deposited films have been characterized by X-ray diffration (XRD) and optical spectroscopy. All samples were polycrystalline with the hexagonal structure and the prefered texture.
  • 216.pdf.jpg
  • Article

  • Sol-gel spin-coating preparation of Zno:In films with highly C-axis orientation

    • Authors: Phung, Quoc Bao; Khuc, Quang Dat; Nguyen, Thien Huong (2004)

  • The c-axis oriented ZnO:In films were prepared by the sol-gel spin-coating process using zinc acetate 2-hydrate, ethylene glycol, indium nitrate 9-hydrate, triethylamine as starting materials. The preferred orientation of the films increased with heat treatment temperature. Near u v and green photoluminescent emisions from the films was observed at room temperature. The PL intensity was found to be greatly dependent on post-deposition heat treatment. Influence of the multilayer deposition on XRD analysis and PL characterisation was also discussed.