In four years of operation at progressively increasing levels of average power new observations on the performance of slits, collimators, and beam dumps of various designs have been accumulated. The inherent longevity of high power beam absorbers based on low-Z or graded-Z design philosophy has been successfully demonstrated. Early operating experience at low power levels in the SLAC beam switc...

Buckling and post-buckling thermomechanical deformations of a functionally graded material (FGM) Timoshenko beam resting on a two-parameter nonlinear elastic foundation and subjected to only a temperature rise have been numerically investigated with the shooting method. The material properties are assumed to vary only in the thickness direction according to a power law function. Through-the-thi...

This work presents a novel computational approach, the DSC regularized Dirac-delta method, for vibration analysis of functionally graded graphene-platelet reinforced (FG-GPLR) porous beams resting on Winkler–Pasternak elastic foundation under moving load. Based Timoshenko beam theory, energy functional model is represented by newly constructed basis function and minimized variational principle....

We demonstrate an all-fiber spatiotemporal mode-locked laser based on graded-index multimode fiber. Due to the high damage threshold of fiber devices, output single-pulse energy reach up 11.67 nJ. The beam quality at state is significantly improved compared with continuous wave as a result self-cleaning effect. By amplifying pulse in amplifier, power pulses can be obtained system MMFs.

In this paper the vibration of a spinning cylindrical shell made of functional graded material is investigated. After a brief introduction of FG materials, by employing higher order theory for shell deformation, constitutive relationships are derived. Next, governing differential equation of spinning cylindrical shell is obtained through utilizing energy method and Hamilton’s principle. Making ...

Abstract Hyperbolic nonlocal theory is applied in this paper to calculate deflections functionally graded nanobeams under uniform load. The developed using the work done principle conjunction with Eringen’s theory. Free stress conditions on upper and lower surfaces are achieved by current hypothesis. Deflection of beam estimated Navier’s approach considering simple ends nanobeam. Solutions foun...

this research develops thermo-elastic analysis of a functionally graded cylinder under thermo-mechanical loadings. heat conduction equation in cylindrical coordinate system is solved. thermal conductivity coefficient is graded along the radial direction. by considering a symmetric distribution of temperature, loading and boundary conditions, strain-displacement and stress-strain relations can b...

In this paper, we present the theoretical studies of a refractive index map to implement a Gauss to a J(0)-Bessel-Gauss convertor. We theoretically demonstrate the viability of a device that could be fabricated on a Si/Si(1-y)O(y)/Si(1-x-y)Ge(x)C(y) platform or by photo-refractive media. The proposed device is 200 μm in length and 25 μm in width, and its refractive index varies in controllable ...

A method to grow a relaxed Si0.5Ge0.5 graded layer with a very smooth surface and a very low threading dislocation density using solid-source molecular-beam epitaxy is reported. This method included the use of Sb as a surfactant for the growth of a 2 mm compositionally graded SiGe buffer with the Ge concentration linearly graded from 0% to 50% followed by a 0.3 mm constant Si0.5Ge0.5 layer. The...

High-quality Ge films were grown on Si substrates by solid-source molecular beam epitaxy using SiGe graded layer and Sb surfactant-mediation technique. Transmission electron microscopy measurements show that samples grown using this method have a lower threading dislocation density than those grown by other typical methods, such as grading at high temperature ~700 °C! only, grading at intermedi...