Abstract: In this paper, a new alignment method based on the particle swarm optimization (PSO) technique is presented. The PSO algorithm is used for locating the optimal coupling position with the highest optical power with three-degrees of freedom alignment. This algorithm gives an interesting results without a need to go thru the complex mathematical modeling of the alignment system. The proposed algorithm is validated considering practical tests considering the alignment of two Single Mode Fibers (SMF) and the alignment of SMF and PCF fibers.
Abstract: Knee joint forces are available by in vivo measurement
using an instrumented knee prosthesis for small to moderate knee
flexion but not for high flexion yet. We created a 2D mathematical
model of the lower limb incorporating several new features such as a
patello-femoral mechanism, a thigh-calf contact at high knee flexion
and co-contracting muscles' force ratio, then used it to determine knee
joint forces arising from high knee flexions in four kneeling
conditions: rising with legs in parallel, with one foot forward, with or
without arm use. With arms used, the maximum values of knee joint
force decreased to about 60% of those with arms not used. When rising
with one foot forward, if arms are not used, the forward leg sustains a
force as large as that sustained when rising with legs parallel.
Abstract: Group-III nitride material as particularly AlxGa1-xN is
one of promising optoelectronic materials to require for shortwavelength
devices. To achieve the high-quality AlxGa1-xN films for
a high performance of such devices, AlN-nucleation layers are the
important factor. To improve the AlN-nucleation layers with a
variation of Ga-addition, XRD measurements were conducted to
analyze the crystalline quality of the subsequent Al0.1Ga0.9N with the
minimum ω-FWHMs of (0002) and (10-10) reflections of 425 arcsec
and 750 arcsec, respectively. SEM and AFM measurements were
performed to observe the surface morphology and TEM
measurements to identify the microstructures and orientations.
Results showed that the optimized Ga-atoms in the Al(Ga)Nnucleation
layers improved the surface diffusion to form moreuniform
crystallites in structure and size, better alignment of each
crystallite, and better homogeneity of island distribution. This, hence,
improves the orientation of epilayers on the Si-surface and finally
improves the crystalline quality and reduces the residual strain of
subsequent Al0.1Ga0.9N layers.