background and aims: a selective and sensitive high performance liquid chromatography-electrospray ionization mass spectrometry method has been established for determination of methotrexate in human plasma. methods: methotrexate was extracted from plasma with acetonitrile. the mobile phase consisted of acetonitrile-water-formic acid 74: 25: 1(v/v). twenty µl of sample was chromatographically an...

Nowadays, the All-Digital Phase-Locked Loop (ADPLL) as a digital electronic circuit is applied in modern communication systems. The main components of ADPLL such as phase detector, loop filter and voltage controlled oscillator which are all digitally discussed in detail. On the other hand, sensitivity to parasitic mismatches in LC oscillators and the limitation of the robustness and the quantiz...

In this paper, three-dimensional (3D) multi-relaxation time (MRT) lattice-Boltzmann (LB) models for multiphase flow are presented. In contrast to the Bhatnagar-GrossKrook (BGK) model, a widely employed kinetic model, in MRT models the rates of relaxation processes owing to collisions of particle populations may be independently adjusted. As a result, the MRT models offer a significant improveme...

Abstract The piezoelectric optomechanical devices supply a promising experimental platform to realize the coherent and effective control measurement of optical circuits working in Terahertz (THz) frequencies via superconducting electron typically Radio (MHz) frequencies. However, quantum fluctuations are unavoidable when size mechanical oscillators enter into nanoscale. consequences noisy envir...

In recent years, multiphase PWMs have been proposed because of their increased efficiency, reduced torque pulsation, improved fault tolerance, and lower power handling requirement by adopting multiphase machines. In the digital implementation, multiphase reference voltages are sampled and fed into the digital modulator to produce gating signals at a constant clock rate f. This means a finite pu...

Many real oscillators are coupled to other oscillators, and the coupling can affect the response of the oscillators to stimuli. We investigate phase-response curves (PRCs) of coupled oscillators. The PRCs for two weakly coupled phase-locked oscillators are analytically obtained in terms of the PRC for uncoupled oscillators and the coupling function of the system. Through simulation and analytic...

There is an unprecedented interest among circuit designers today to obtain insight into mechanisms of phase noise in LC oscillators. For only with this insight is it possible to optimize oscillator circuits using low-quality integrated resonators to comply with the exacting phase noise specifications of modern wireless systems. Various numerical simulators are now available to assist the circui...

In this paper we discuss upscaling of immiscible multiphase and miscible multicomponent flow and transport in heterogeneous porous media. The discussion presented in the paper summarizes the results of in Upscaled Modeling in Multiphase Flow Applications by Ginting et al. (2004) and in Upscaling of Multiphase and Multicomponent Flow by Ginting et al. (2006). Perturbation approaches are used to ...

The modern queueing theory is one of the powerful tools for a quantitative and qualitative analysis of communication systems, computer networks, transportation systems, and many other technical systems. In this paper, we deal with approximations of multiphase queueing systems (tandem queues, queues in series). Multiphase queueing systems are of special interest both in theory and in practical a...

This paper presents a Buckley-Leverett analytical solution for non-Darcy displacement of two immiscible fluids in porous media. The multiphase non-Darcy displacement is described using a Forchheimer equation or other non-Darcy flow correlations under multiphase flow conditions. The analytical solution is used to obtain some insight into the physics of displacement involving non-Darcy flow effec...