A triple frequency capacitively coupled plasma （TF-CCP） has been considered to investigate the behavior of the sheath parameters. A self-consistent time-independent collisionless model has been developed. The sheath...A triple frequency capacitively coupled plasma （TF-CCP） has been considered to investigate the behavior of the sheath parameters. A self-consistent time-independent collisionless model has been developed. The sheath width and potential are calculated using the present model and compared with those calculated using a single-frequency （SF）, a dual-frequency （DF） and a triple-frequency （TF） model for time independent collisionless cases. The sheath motion and sheath potential are found to be larger compared with those of SF and DF CCPs for an inhomogeneous sheath, and that of TF CCP for a homogeneous sheath. The effects of the source parameters, i.e., current magnitudes, frequencies and phase difference, on the sheath parameters are investigated. The sheath parameters show higher values at higher source currents whereas they decrease with the increase of excitation frequencies. It has also been found that, by the proper choice of source frequencies and phase differences, it is possible to adjust the energy of ions when they hit the electrode.展开更多
Mango(Mangifera indica)is an important,and popular fruit in Bangladesh.However,the post-harvest processing of it is still mostly performed manually,a situation far from satisfactory,in terms of accuracy and throughput...Mango(Mangifera indica)is an important,and popular fruit in Bangladesh.However,the post-harvest processing of it is still mostly performed manually,a situation far from satisfactory,in terms of accuracy and throughput.To automate the grading of mangos(geometry and shape),we developed an image acquisition and processing system to extract projected area,perimeter,and roundness features.In this system,images were acquired using a XGA format color camera of 8-bit gray levels using fluorescent lighting.An image processing algorithm based on region based global thresholding color binarization,combined with median filter and morphological analysis was developed to classify mangos into one of three mass grades such as large,medium,and small.This system achieved an accuracy of 97% for projected area and Feret diameter,79% for perimeter,and 36% for roundness.To achieve a finer grading,two different grading features could be used in sequence.The image grading system is simple and efficient and can be considered a suitable first stage to mechanizing the commercial grading of mangos in Bangladesh.Moreover,the method has the potential to be applied to other crops with suitable adjustments.展开更多
文摘A triple frequency capacitively coupled plasma （TF-CCP） has been considered to investigate the behavior of the sheath parameters. A self-consistent time-independent collisionless model has been developed. The sheath width and potential are calculated using the present model and compared with those calculated using a single-frequency （SF）, a dual-frequency （DF） and a triple-frequency （TF） model for time independent collisionless cases. The sheath motion and sheath potential are found to be larger compared with those of SF and DF CCPs for an inhomogeneous sheath, and that of TF CCP for a homogeneous sheath. The effects of the source parameters, i.e., current magnitudes, frequencies and phase difference, on the sheath parameters are investigated. The sheath parameters show higher values at higher source currents whereas they decrease with the increase of excitation frequencies. It has also been found that, by the proper choice of source frequencies and phase differences, it is possible to adjust the energy of ions when they hit the electrode.
基金partially supported by the TWAS(Ref.:13-311 RG/ITC/AS_C)MoICT,Bangladesh(code:3-0001-2801-5965).
文摘Mango(Mangifera indica)is an important,and popular fruit in Bangladesh.However,the post-harvest processing of it is still mostly performed manually,a situation far from satisfactory,in terms of accuracy and throughput.To automate the grading of mangos(geometry and shape),we developed an image acquisition and processing system to extract projected area,perimeter,and roundness features.In this system,images were acquired using a XGA format color camera of 8-bit gray levels using fluorescent lighting.An image processing algorithm based on region based global thresholding color binarization,combined with median filter and morphological analysis was developed to classify mangos into one of three mass grades such as large,medium,and small.This system achieved an accuracy of 97% for projected area and Feret diameter,79% for perimeter,and 36% for roundness.To achieve a finer grading,two different grading features could be used in sequence.The image grading system is simple and efficient and can be considered a suitable first stage to mechanizing the commercial grading of mangos in Bangladesh.Moreover,the method has the potential to be applied to other crops with suitable adjustments.
