Effects of a Recessed Camel-gate Head Structure on Normally-off AlGaN/GaN HEMTs

Mansoor Ali Khan,허준우,김영진,박현창,박형무,김현석,문재경 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.5

In this paper, a standalone camel-gate (┐) head structure has been studied to investigate the effects of the field plate (FP) in the source access region in AlGaN/GaN high electron mobility transistors (HEMTs). The camel gate serves as an FP toward the source side. Using this concept of the camel gate, the transconductance and other forward characteristics have been analyzed with regard to the T-gate. It is confirmed that the recessed camel-gate FP scaling enhances the breakdown voltage, transconductance, and output current by reducing the electric field, leakage current, and dispersion in the source access regime. Further, the optimized recessed camel-gate AlGaN/GaN HEMT is suitable for use in RF devices, as it exhibits a frequency in the order of gigahertz.

Diversity in Betasatellites Associated with Cotton Leaf Curl Disease During Source-To-Sink Movement Through a Resistant Host

Khan, Iftikhar Ali,Akhtar, Khalid Pervaiz,Akbar, Fazal,Hassan, Ishtiaq,Amin, Imran,Saeed, Muhammad,Mansoor, Shahid The Korean Society of Plant Pathology 2016 Plant Pathology Journal Vol.32 No.1

Cotton leaf curl is devastating disease of cotton characterized by leaf curling, vein darkening and enations. The disease symptoms are induced by DNA satellite known as Cotton leaf curl Multan betasatellite (CLCuMuB), dominant betasatellite in cotton but another betasatellite known as Chili leaf curl betasatellite (ChLCB) is also found associated with the disease. Grafting experiment was performed to determine if host plant resistance is determinant of dominant population of betasatellite in cotton (several distinct strains of CLCuMuB are associated with the disease). Infected scion of Gossypium hirsutum collected from field (the source) was grafted on G. arboreum, a diploid cotton species, resistant to the disease. A healthy scion of G. hirsutum (sink) was grafted at the top of G. arboreum to determine the movement of virus/betasatellite to upper susceptible scion of G. hirsutum. Symptoms of disease appeared in the upper scion and presence of virus/betasatellite in the upper scion was confirmed via molecular techniques, showing that virus/betasatellite was able to move to upper scion through resistant G. arboreum. However, no symptoms appeared on G. arboreum. Betasatelites were cloned and sequenced from lower scion, upper scion and G. arboreum which show that the lower scion contained both CLCuMuB and ChLCB, however only ChLCB was found in G. arboreum. The upper scion contained CLCuMuB with a deletion of 78 nucleotides (nt) in the non-coding region between Arich sequence and ${\beta}C1$ gene and insertion of 27 nt in the middle of ${\beta}C1$ ORF. This study may help in investigating molecular basis of resistance in G. arboreum.

Diversity in Betasatellites Associated with Cotton Leaf Curl Disease During Source-To-Sink Movement Through a Resistant Host

Iftikhar Ali Khan,Khalid Pervaiz Akhtar,Fazal Akbar,Ishtiaq Hassan,Imran Amin,Muhammad Saeed,Shahid Mansoor 한국식물병리학회 2016 Plant Pathology Journal Vol.32 No.1

Cotton leaf curl is devastating disease of cotton characterized by leaf curling, vein darkening and enations. The disease symptoms are induced by DNA satellite known as Cotton leaf curl Multan betasatellite (CLCuMuB), dominant betasatellite in cotton but another betasatellite known as Chili leaf curl betasatellite (ChLCB) is also found associated with the disease. Grafting experiment was performed to determine if host plant resistance is determinant of dominant population of betasatellite in cotton (several distinct strains of CLCuMuB are associated with the disease). Infected scion of Gossypium hirsutum collected from field (the source) was grafted on G. arboreum, a diploid cotton species, resistant to the disease. A healthy scion of G. hirsutum (sink) was grafted at the top of G. arboreum to determine the movement of virus/betasatellite to upper susceptible scion of G. hirsutum. Symptoms of disease appeared in the upper scion and presence of virus/betasatellite in the upper scion was confirmed via molecular techniques, showing that virus/betasatellite was able to move to upper scion through resistant G. arboreum. However, no symptoms appeared on G. arboreum. Betasatelites were cloned and sequenced from lower scion, upper scion and G. arboreum which show that the lower scion contained both CLCuMuB and ChLCB, however only ChLCB was found in G. arboreum. The upper scion contained CLCuMuB with a deletion of 78 nucleotides (nt) in the non-coding region between Arich sequence and βC1 gene and insertion of 27 nt in the middle of βC1 ORF. This study may help in investigating molecular basis of resistance in G. arboreum.

Attitude Control of Quadcopter Using Adaptive Neuro Fuzzy Control

Asif Sajjad Khan Anjum,Rana Ali Sufian,Zain Abbas,Ijaz Mansoor Qureshi 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.4

This research contains the simulation and designing of Quadcopter using Adaptive Neuro Fuzzy Controller to control the altitude of quadcopter and obstacle detection. Now a day’s advancement in technology has made it possible to develop low power and lightweight with accurate sensors which are used with controllers for controlling, which have high processing power but small power consumption. This has been allowed for the development of complex and difficult control systems that can be implemented onboard UAV. With this combination of high precision and light weight, real-time onboard navigation or guidance and autonomous flights are now practical. This research work used a Fuzzy controller to control the pitch angle of quadcopter and avoiding obstacles. The fuzzy controller receives the sensory data and adjust the pitch accordingly until unless it finds the clear path. For detecting obstacles the IR sensors are used. For designing a fuzzy inference system used Sugeno model and used mat lab commands to design ANFIS as we have another method for designing by using a Simulink as well. ANFIS designed is based on kinematics and dynamics equation of quadcopter that will be able to control the pitch of quadcopter. Simulations results in mat lab show that by using ANFIS the performance of Quadcopter will be improved significantly.

Improved Stability and Damping Characteristics of LCL-Filter Based Distributed Generation System

Faiz Muhammad Talib,Khan Danish,Khan Muhammad Mansoor,Ali Abdar,Tang Houjun 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

The voltage source inverter is a key component in the distributed power generation systems where the LCL -fi lter is a popular choice for interfacing with the grid. However, the well-known resonance issue associated with the LCL -fi lter deteriorates the control performance and risk the inverter system stability. The inverter control design plays a signifi cant role to ensure the quality of the injected grid current and stable operation according to the requirements of grid interconnection standards. This paper deals with an alternative control design method that modifi es the internal damping loop design to improve the stability and damping characteristics. The proposed design employs a compensator across the fi lter and feedbacks the output of the augmented plant at the reference voltage point, and named as parallel feedforward compensation method. The fi lter capacitor current measured for damping loop implementation, and a high-pass fi lter compensator adopted in the proposed confi guration. The proportional capacitor current feedback compensation method is considered for comparative studies. The current loop stability and control performance characteristics are investigated in detail under the resonance frequency and fi lter parameters variation condition. The signifi cant outcomes of the proposed scheme are faster dynamic response, higher delay compensation capability, relatively improved resonance suppression, and potential for better tracking performance. An experimental prototype is developed to validate the effi cacy of the proposed method.