performance of the fiber optic networks with different physical topologies such as point-to-point, bus, ring and star, with respect to requirements as bit rates, topology structure, bit. error rate (ber) and optical component characteristics including optical amplifiers, filters, sources and detectors, are analyzed and simulated. for this purpose, maximum number of supportable nodes and throug...

Cigarette smoking is growing and nicotine is considered as the most adverse agent in the cigarette smoking. Nicotine is an alkaloid and forms 90% of alkaloids of cigarette. Nicotine is accountable for creating disorders and cancers such as lung cancer, heart disease and chronic lung disease. Nicotine can be considered as an autophagy and apoptosis inducer which can either directly or indirectly...

In this paper, we present an analytical model to analysis the kirk effect onstatic and dynamic responses of quantum well heterojunction bipolar transistor lasers(HBTLs). Our analysis is based on solving the kirk current equation, continuityequation and rate equations of HBTL. We compare the performance (current gain,output photon number and small signal modulation bandwi...

this paper presents a comparative analysis between two current control strategies, constant source power and generalized fryze current, used in active power filter (apf) applications having three different modulation methods. the hysteresis band (hb) and first-order delta-sigma modulation (dsm) as well as the second-order dsm is applied. the power section of the active power filter is viewed as...

background and objective: vep is a powerful method to study visual system via evaluating evoked potentials. technologic and instrumental restrictions may be the reason of having studies on optical modulation and induction such as color, spatial frequency and contrast. developments of computer software and hardware may lead to an increase in the flexibility of pattern designs. material and meth...

static properties, relatively intensity noise and intensity modulation response in quantum cascade lasers (qcls) studied theoretically in this paper. the present rate equations model consists of three equations for the electrons density in the conduction band and one equation for photons density in cavity length. two equations were derived to calculate the noise and modulation response. calcula...

in this study, a new adaptive controller is proposed for position control of pneumatic systems. difficulties associated with the mathematical model of the system in addition to the instability caused by pulse width modulation (pwm) in the learning-based controllers using gradient descent, motivate the development of a new approach for pwm pneumatics. in this study, two modified feedback error l...

introduction: it is known that acute and chronic stress induce hormonal and neuronal changes which affecting both pain threshold and nociceptive behaviours. orexin plays an important role in modulation of pain and stress. considering pain modulation during stress and the role of orexin in pain and stress, orexin might be involved in pain modulation during stress.we evaluated the involvement of ...

Introduction: The present study aimed to generate intensity-modulated beams with Aluminium compensating filters for a conventional telecobalt machine based on the outputs of a treatment planning system (TPS) performing forward planning and cannot simulate directly the compensating filter. Materials and Methods: In order to achieve the beam intensity modulation during treatment planning with th...