Optical coherence tomography of luminal structures, such as for intravascular or gastrointestinal imaging, is performed by using a fiber-optic catheter as a beam-delivery probe. The interrogating beam is scanned angularly by rotating the fiber around a fixed central axis. Because the beam is focused only at a fixed distance from the center of the fiber, only scatterers near this distance are re...

This thesis extends and updates the N__qodal Design of Actuators and Sensors (NODAS) library previously developed at Carnegie Mellon University. NODAS is a library of atomic element lumped parameter behavioral models written in Verilog-A, an analog hardware description language (AHDL). It is used for the simulation of MEMS devices in a SPICE-like circuit simulator. Physics modeling, accuracy ve...

The purpose of the present work is to quantify the coupled effects of surface stresses and boundary conditions on the resonant properties of silicon nanowires. We accomplish this by using the surface Cauchy–Born model, which is a nonlinear, finite deformation continuum mechanics model that enables the determination of the nanowire resonant frequencies including surface stress effects through so...

Abstract The present paper investigates how an axial load can change the natural frequencies of heterogeneous fixed–fixed beams with intermediate roller support. problem is treated as a three-point boundary value (eigenvalue problem) that paired homogeneous conditions. Green functions are determined for unloaded and pre-loaded well—in later case, both compression tension. With these, eigenvalue...

moment-resisting frames have extensive usage in earthquake-prone areas and high ability in energy dissipation.after the earthquake in northridge 1994,kobe 1995 fixed connections of steel structures have shown poor performance and generally they were caught brittle fracture of beam flange weld to the column.in order to remedy to avoid similar situations in future earthquakes,researchers introduc...

Based on realistic Monte-Carlo simulations a two-stage beam collimation system is designed to minimize the beam loss in the Fermilab Tevatron for fixed target and collider Run II. Thin primary collimators are used to increase particle amplitude and their impact parameter on the downstream secondary collimators. This results in a significant reduction of the total beam loss in the machine, decre...

The flat inflationary dust universe with matter creation proposed by Prigogine and coworkers is generalized and its dynamical properties are reexamined. It is shown that the starting point of these models depends critically on a dimensionless parameter Σ, closely related to the matter creation rate ψ. For Σ bigger or smaller than unity flat universes can emerge, respectively, either like a Big-...

in this paper, an interference management for multi-beam satellite network to enhance spectral efficiency is studied. first, a two-satellite for future generation satellite network using cognitive radio technology is provided.this network is composed of a secondary satellite and aprimary satellite where the primary satellite system does not suffer from severe destructive interferences coming fr...