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Analysis and Characterization of Normally-Off Gallium Nitride High Electron mobility Transistors

Computers, materials & Continua 2021年第10期69卷 1021-1037页

作者： Shahzaib Anwar Sardar muhammad Gulfam Bilal muhammad syed Junaid Nawaz Khursheed Aurangzeb mohammad Kaleem Department of Electrical and Computer Engineering COMSATS University Islamabad(CUI)Islamabad45550Pakistan CTIF Global Capsule Department of Business Development and TechnologyAarhus University7400HerningDenmark Computer Engineering Department College of Computer and Information SciencesKing Saud UniversityRiyadh11543Saudi Arabia

High electron mobility transistor(HEmT)based on gallium nitride(GaN)is one of the most promising candidates for the future generation of high frequencies and high-power electronic *** research work aims at designing and characterization of enhancement-mode or normally-off GaN *** impact of variations in gate length,mole concentration,barrier variations and other important design parameters on the performance of normally-off GaN HEmT is thoroughly *** increase in the gate length causes a decrease in the drain current and transconductance,while an increase in drain current and transconductance can be achieved by increasing the concentration of aluminium(Al).For Al mole fractions of 23%,25%,and 27%,within Al gallium nitride(AlGaN)barrier,the GaN HEmT devices provide a maximum drain current of 347,408 and 474 mA/μm and a transconductance of 19,20.2,21.5 mS/μm,***,for Al mole fraction of 10%and 15%,within AlGaN buffer,these devices are observed to provide a drain current of 329 and 283 mA/μm,***,for a gate length of 2.4,3.4,and 4.4μm,the device is observed to exhibit a maximum drain current of 272,235,and 221 mA/μm and the transconductance of 16.2,14,and 12.3 mS/μm,*** is established that a maximum drain current of 997 mA/μm can be achieved with an Al concentration of 23%,and the device exhibits a steady drain current with enhanced *** observations demonstrate tremendous potential for two-dimensional electron gas(2DEG)for securing of the normally-off mode operation.A suitable setting of gate length and other design parameters is critical in preserving the normally-off mode operation while also enhancing the critical performance parameters at the same *** to the normallyon depletion-mode nature of GaN HEmT,it is usually not considered as suitable for high power levels,frequencies,and *** such settings,a negative bias is required to enter the blocking conditi

关键词： High electron mobility GaN HEmT bipolar transistors gallium nitride heterojunctions mOS devices

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Spatial configuration engineering of perylenediimide-based non-fullerene electron transport materials for efficient inverted perovskite solar cells

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Journal of Energy Chemistry 2021年第5期30卷 374-382页

作者： mengmeng Zheng Yawei miao Ali Asgher syed Cheng Chen Xichuan Yang Liming Ding Huaming Li ming Cheng Institute for Energy Research School of Materials Science&EngineeringJiangsu UniversityZhenjiang 212013JiangsuChina State Key Laboratory of Fine Chemicals Institute of Artificial PhotosynthesisDUT−KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology(DUT)Dalian 116024LiaoningChina Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Due to their excellent photoelectron chemical properties and suitable energy level alignment with perovskite,perylene diimide(PDI)derivatives are competitive non-fullerene electron transport material(ETm)candidates for perovskite solar cells(PSCs).However,the conjugated rigid plane structure of PDI units result in PDI-based ETms tending to form large aggregates,limiting their application and photovoltaic *** this study,to restrict aggregation and further enhance the photovoltaic performance of PDI-type ETms,two PDI-based ETms,termed PDO-PDI2(dimer)and PDO-PDI3(trimer),were constructed by introducing a phenothiazine 5,5-dioxide(PDO)core building *** research manifests that the optoelectronic properties and film formation property of PDO-PDI2 and PDO-PDI3 were deeply affected by the molecular spatial *** in PSCs,PDO-PDI3 with threedimensional spiral molecular structure,exhibits superior electron extraction and transport properties,further achieving the best PCE of 18.72%and maintaining 93%of its initial efficiency after a 720-h aging test under ambient conditions.

关键词： Non-fullerene Electron transport material Perovskite solar cell Inverted structure

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modeling the effects of rainfall on vehicular traffic

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Journal of modern Transportation 2018年第2期26卷 133-146页

作者： Etikaf Hussain syed Imran Ahmed mir Shabbar Ali Civil Engineering Department NED University of Engineering & Technology Faculty of Civil Engineering and Architecture NED University of Engineering & Technology

Traffic management and drainage system are two vital issues for any metropolitan city. Like other big cities, Karachi is also facing problems due to lack of traffic management and poor drainage system. The main objective of the study is to model the interdisciplinary issues of storm water and its effect on the traffic of Karachi. The specific objectives are （1） to calibrate and validate urban hydraulic and traffic micro-simulation models and （2） to model storm water and traffic for future conditions. This study is carried out on a 3-km section of arterial road. In this study, loose coupling of two models is done. For urban drainage, PCSWmm, and for traffic, VISSIm is used. Both models are calibrated for an existing situation on rainfall event of August 3, 2013, and then used for prediction of future scenario based on 50-year and 100-year return periods of rainfall. Sensitivity analysis of VISSIm is performed. Locations and lengths of road sections, where ponding happens for the future scenario, are identified using PCSWmm. These lengths axe then marked in VISSIm as low-speed areas, and delays are measured. Analysis of PCSWmm shows that for 100-year return period, there is maximum 0.318 ha-m （3180 cubic meters） water stored in the depressions of the road after 10 h of rainfall. Analysis of VISSIm shows that for a 100-year return period, there is a maximum delay of 35 min on NIPA to Hasan Square section of University Road.

关键词： Traffic micro-simulation Hydraulic modeling Rainfall Delays Ponding

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Development and validation of a sensitive HPLC method for the determination of lisinopril in human plasma after derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole

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Journal of Chinese Pharmaceutical Sciences 2018年第9期27卷 623-629页

作者： Reza Ahmadkhaniha Noushin Rastkari syed Husain Hashemi mousavi Effat Souri Department of Human Ecology School of Public HealthTehran University of Medical Sciences Center for Air Pollution Research (CAPR) Institute for Environmental Research (IER)Tehran University of Medical Sciences Department of Chemistry Faculty of EngineeringSouth Tehran BranchIslamic Azad University Department of medicinal Chemistry Faculty of Pharmacy and Pharmaceutical Sciences Research CenterTehran University of Medical Sciences

In this study, we developed a simple and sensitive HPLC method for the determination of lisinopril in human plasma. The sample clean-up was carried out by solid-phase extraction(SPE) using a cation-exchange(Strata-SCX~?) extraction cartridge. After a pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole, the reaction mixture was analyzed on an Agilent Zorbax SB~?-C_(18)(150 mm×4.6 mm, 5 μm). The flow rate was set at 1.0 mL/min. Fluorescence detection was performed at an excitation wavelength of 470 nm and an emission wavelength of 530 nm. The mobile phase consisted of a mixture of methanol and 0.02 m sodium dihydrogen phosphate(pH = 3.0, 60:40, v/v). The average extraction recovery of lisinopril and fluvoxamine(internal standard) was >85%. The method exhibited a linear calibration curve over the concentration range of 1–1000 ng/mL with a correlation coefficient(r^2) of ≥0.98 and a limit of quantification(LOQ) equal to 2 ng/mL. The within-run and between-run precisions were satisfactory with an RSD of 3.8%–13.7%(accuracy: from 95.0% to 96.4%) and 4.273%–14.3%(accuracy: from 94.4% to 98.5%), respectively.

关键词： Lisinopril HPLC Derivatization 4-Fluoro-7-nitro-2,1,3,-benzoxadiazole

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Run-Up Flow of a maxwell Fluid through a Parallel Plate Channel

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American Journal of Computational mathematics 2013年第4期3卷 297-303页

作者： syed Yedulla Qadri m. Veera Krishna Department of mathematics Rayalaseema University Kurnool India Department of mathematics St. Josephs PG College Kurnool India

We consider the flow of an incompressible viscous maxwell fluid between two parallel plates, initially induced by a constant pressure gradient. The pressure gradient is withdrawn and the upper plate moves with a uniform velocity while the lower plate continues to be at rest. The arising flow is referred to as run-up flow. The unsteady governing equations are solved as initial value problem using Laplace transform technique. The expression for velocity, shear stresses on both plates and discharge are obtained. The behavior of the velocity, shear stresses and mass flux has been discussed in detail with respect to variations in different governing flow parameters and is presented through graphs.

关键词： Run-Up Flow maxwell’s Fluid Laplace Transforms Reynolds Number and Parallel Plate Channels

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Fabrication and Characterization of PLD-Grown Bismuth Telluride (Bi2Te3) and Antimony Telluride (Sb2Te3) Thermoelectric Devices

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Journal of Electronics Cooling and Thermal Control 2017年第3期7卷 63-77页

作者： Ibrahim m.Abdel-motaleb syed m.Qadri Department of Electrical Engineering Northern Illinois UniversityDeKalbILUSA

We report on the fabrication and characterization of multi-leg bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) thermoelectric devices. The two materials were deposited, on top of SiO2/Si substrates, using Pulsed Laser Deposition (PLD). The SiO2 layer was used to provide insulation between the devices and the Si wafer. Copper was used as an electrical connector and a contact for the junctions. Four devices were built, where the Bi2Te3 and Sb2Te3 were deposited at substrate temperatures of 100°C, 200°C, 300°C and 400°C. The results show that the device has a voltage sensitivity of up to 146 μV/K and temperature sensitivity of 6.8 K/mV.

关键词： Thermoelectric Devices Bismuth Telluride Bi2Te3 Antimony Telluride Sb2Te3 Pulsed Laser Deposition PLD Seebeck Effect

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multi-Physics Numerical Simulation of Thermoelectric Devices

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Journal of Electronics Cooling and Thermal Control 2017年第4期7卷 123-135页

作者： Ibrahim m. Abdel-motaleb syed m. Qadri Department of Electrical Engineering Northern Illinois University DeKalb IL USA

To optimize the performance of a thermoelectric device for a specific application, the device should be uniquely designed for the application. Achieving an optimum design requires accurate measurements and credible analysis to evaluate the performance of the device and its relationship with the device parameters. To do that, we designed, fabricated, and tested four devices based on Bi2Te3 and Sb2Te3. To evaluate the accuracy of our analysis, experimental measurements were compared with the numerical simulation performed using COmSOLTm. The two sets of results were found to be in full agreement. This is a proof of the accuracy of our experimental measurements and the credibility of our simulation. The study shows that testing or simulating the devices without heat sink will lead to skewed results. This is because the junction will not hold its temperatures value, but will, instead, automatically change its value to the direction of thermal equilibrium. The study shows also that there is no reciprocity between the input and the output characteristics of the devices. Therefore, a device optimized for cooling and heating may not be automatically optimized for energy harvesting. For heating and cooling, temperature sensitivity should be optimized;while for energy harvesting, voltage sensitivity should be optimized. Using heat sink, our devices achieved a voltage sensitivity of 187.77 μV/K and a temperature sensitivity of 6.12 K/mV.

关键词： Thermoelectric Devices multi-Leg Devices Bi2Te3 Sb2Te3 COmSOL Fi-nite Element Simulation Voltage Sensitivity Temperature Sensitivity

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mechanism of Infrared Detection and Transduction by Beetle melanophila Acuminata In memory of Jerry Wolken

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Journal of Bionic Engineering 2011年第2期8卷 129-139页

作者： meir Israelowitz Jeong-Ah Kwon syed W. H. Rizvi Christoph Gille Herb P. von Schroeder Biomimetics Technologies Inc. 191 Ellis Avenue Toronto Ontario M6S 2X4 Canada Hillman Cancer Center Research Pavilion Floor 2 2.35 5117 Centre Avenue Pittsburgh PA 15213 USA Institute of Biochemistry CharitO Universiaitsmedizin Monbijourstr. 2 10117 Berlin Germany University of Toronto 399 Bathurst Street 2E Tolvnto ON M5T2SS Canada

The melanophila acuminata beetle is attracted to forest fires via a pair of infrared sensory organs composed of sensilla. Our histological work showed that each sensillum contains lipid layers surrounding a protein layer and a unique polysaccharide base that is associated with a neuron to each sensillum. Infrared microscopy showed that the protein region maximally absorbs infrared radiation at 3 ~tm wavelength and at 10 ~tm, which corresponds to the known radiation produced by forest fires at 3 ~tm. mathematical calculations showed that the physical properties of the sensilla are such that the expected temperature rise is insufficient for transduction of the infrared signal through mechanical means or as a thermal receptor as previously thought; hence the protein plays the pivotal role in perception of single photons and transmission of the signal within the sensilla.

关键词： sensory organs sensillum insect radiation fire

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A case of cellulitis of the hands caused by a predatory bird attack

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Asian Pacific Journal of Tropical Biomedicine 2011年第2期1卷 166-168页

作者： m Adil Abbas Khan m.ham.ed Farid Zain A Sobani syed Nadir Ali Huzaifa malick maryam Baqir Hasanat Sharif m Asim Beg Department of Plastic and Reconstructive Surgery University Hospital Birmingham NHS TrustSelly Oak Hospital medical College Aga Khan University Department of Surgery Aga Khan University Department of Pathology and microbiology Aga Khan University

many species have been drastically affected by rapid ***' s hawks from their natural habitat of open spaces and a supply of rodents,lizards and other small prey have been forced to change their natural environment adapting to living in open spaces in sub-and periurban *** areas include playgrounds,parks and school *** migration of this predatory species into these areas poses a risk to individuals,and especially the children are often attacked by claws,talons and beaks intentionally or as collateral damage while attacking rodent *** addition,the diverse micro-organisms harbored in the beaks and talons can result in wound infections,presenting a challenge to clinical *** we would like to present a case of an 80-year-old man with cellulitis of bom hands after sustaining minor injuries from the talons of a Harris s hawk and review the management *** would also like to draw attention to the matter that,even though previously a rarity,more cases of injuries caused by birds of prey may be seen in hospital settings.

关键词： Harris hawk Predatory birds Deforestation Urbanization

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An Efficient Impersonation Attack Detection method in Fog Computing

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Computers, materials & Continua 2021年第7期68卷 267-281页

作者： Jialin Wan muhammad Waqas Shanshan Tu syed mudassir Hussain Ahsan Shah Sadaqat Ur Rehman muhammad Hanif Engineering Research Center of Intelligent Perception and Autonomous Control Faculty of Information TechnologyBeijing University of TechnologyBeijing100124China Faculty of Computer Science and Engineering Ghulam Ishaq Khan Institute of Engineering Sciences and TechnologyTopi23460Pakistan Department of Electronics Engineering FICTBalochistan University of Information TechnologyEngineering and Management SciencesQuetta87300Pakistan Department of Computer Science Namal InstituteMianwali42200Pakistan

Fog computing paradigm extends computing,communication,storage,and network resources to the network’s *** the fog layer is located between cloud and end-users,it can provide more convenience and timely services to ***,in fog computing(FC),attackers can behave as real fog nodes or end-users to provide malicious services in the *** attacker acts as an impersonator to impersonate other legitimate ***,in this work,we present a detection technique to secure the FC ***,we model a physical layer key generation based on wireless channel *** generate the secret keys between the legitimate users and avoid impersonators,we then consider a Double Sarsa technique to identify the impersonators at the receiver *** compare our proposed Double Sarsa technique with the other two methods to validate our work,i.e.,Sarsa and *** simulation results demonstrate that the method based on Double Sarsa outperforms Sarsa and Q-learning approaches in terms of false alarm rate(FAR),miss detection rate(mDR),and average error rate(AER).

关键词： Fog computing double Sarsa attack detection physical layer key security

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