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In this work, we report a detailed comparison of electron-acoustic-phonon (EAP) interaction strength in symmetric (parabolic) and asymmetric (semi-parabolic) quantum-wells (QWs) for both GaAs and GaN materials. The operator projection method will be utilized to calculate the acoustic-phonon-assisted cyclotron resonance (CR) absorption power. The EAP interaction strength is determined by measuring the full width at half maximum (FWHM) of the acoustic-phonon-assisted CR absorption peak based on the profile of the curve describing the dependence of the acoustic-phonon-assisted CR absorption power on the photon energy. The studied result reveals that the EAP interaction strengths in the symmetric and asymmetric QWs are functions of the electron temperature (ET), external magnetic field (EMF), and confined potential frequency (CPF). Namely, the larger the ET, the EMF, and the CPF, the stronger the EAP interaction strengths in the symmetric and asymmetric QWs are for both GaN and GaAs materials. More importantly, the obtained result demonstrates that under the influence of the structural (CPF) and external (ET and EMF) parameters, the EAP interaction strength in the symmetric QW is always much stronger than that in the asymmetric QW for both GaN and GaAs materials. Simultaneously, the EAP interaction strength in the GaN material is much stronger than that in the GaAs material for both the symmetric and asymmetric QWs.
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In this paper, the magneto-optical transport (MOT) properties of III-nitride Pöschl-Teller quantum well (QW) semiconductors, including AlN, GaN, and InN, resulting from the acoustic phonon interaction are thoroughly investigated and compared by applying the technique of operator projection. In particular, a comparison is made between the Pöschl-Teller QW results and the square QW ones. The findings demonstrate that the MOT properties of III-nitride QW semiconductors resulting from acoustic phonon scattering are strongly influenced by the quantum system (QS) temperature, applied magnetic field, and QW width. When the applied magnetic field and QS temperature increase, the absorbing FWHM in AlN, GaN, and InN increases; on the other hand, it diminishes when the QW's width increases. The absorbing FWHM in GaN is smaller and varies slower compared with AlN; inversely, it is larger and varies faster compared with InN. In other words, the absorbing FWHM in AlN is the largest and the smallest in InN. Compared to the square QW in AlN, GaN, and InN, the absorbing FWHMs in the Pöschl-Teller QW vary more quickly and have greater values. The absorbing FWHMs resulting from the acoustic phonon interaction in III-nitrides are strongly dependent on the nanostructure's geometric shape and parameters. Our findings provide useful information for the development of electronic devices.
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INTRODUCTION: This study provides an analysis of head and neck cancer (HNC) cases over a 20-year period in Ho Chi Minh City, Vietnam. It aims to shed light on HNC's characteristics and trends in this highly populated urban region. METHODS: The analysis encompasses 8974 HNC cases, emphasising incidence rates, gender distribution, and the prevalence of different subtypes, including oral cavity, nasopharyngeal, oropharyngeal, and laryngeal/pharyngeal cancers. Ho Chi Minh City was chosen due to its extensive cancer reporting systems and its role as a major urban healthcare centre attracting a wide range of patients. RESULTS: The study reveals an increasing incidence of HNC in Ho Chi Minh City, with a notable predominance of male patients (73â¯%). The breakdown of HNC cases shows oral cavity cancer at 34â¯%, nasopharyngeal at 33â¯%, oropharyngeal at 12â¯%, and laryngeal/pharyngeal at 21â¯%. Compared to global averages, Vietnamese patients are diagnosed at an earlier age, with a noticeable trend of decreasing mean age of diagnosis over the study period. CONCLUSION: This comprehensive study provides valuable insights into the HNC landscape in Ho Chi Minh City, revealing a slightly lower overall incidence but an earlier age of diagnosis compared to global trends. These findings suggest the need for region-specific public health initiatives and further research to clarify the epidemiological features of HNC in Vietnam.
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Two-dimensional (2D) structures can stably exist in different allotropes. In this manuscript, we propose a new series of Janus structures based on the ß-phase of germanium monochalcogenides, namely, ß-Ge2XY (X/Y = S, Se, and Te) monolayers. Our calculations indicate that Janus ß-Ge2XY monolayers have a stable crystal structure and possess anisotropic mechanical properties. At the ground state, ß-Ge2XY monolayers are semiconductors with a large bandgap and their electronic properties depend strongly on a biaxial strain. Strains not only change the bandgap but can also lead to a change in the bandgap characteristic, namely transitions from indirect to direct bandgap. Our findings not only introduce a new structure of germanium chalcogenide compounds but also show that they have superior physical properties suitable for applications in nanoelectronics.