A polarization splitter and rotator (PSR) based on a tapered directional coupler with relaxed fabrication tolerance is proposed and demonstrated on the silicon-on-insulator platform. The device is simply constructed by parallel-coupling a narrow silicon waveguide with a linearly tapered wider waveguide. Compared to previously reported PSRs based on a normal directional coupler, which suffer fro...

Key points † Optimizing tracheal sealing is of clinical interest: fluid leakage past the tube cuff plays an important role in the pathogenesis of VAP. † Tapered shaped tube cuff offering a sealing zone with reduced folds and channels is a new strategy to minimize fluid leakage past the tracheal tube cuff. † Tracheal tube cuffs made from PVC show much more and faster fluid leakage than cuffs mad...

This study evaluated the effect of surface roughness and tapered angle of cone crowns on retentive force (RF). Cone crowns from Ti-6Al-7Nb alloy with a tapered angle of 4, 5, or 6° were fabricated using a milling machine and a finishing machine to produce a smooth surface. Cone crowns of 6° with a rough surface were also prepared. The RF during 1,000 cycles of insertion/separation was recorded....

In this paper, 3D flow past a long tapered tower is examined. A tapered tower is described by the taper ratio. Tapered cylinders are a good description of many structures, like wind turbine tower e.t.c. Similar to the flow around cylinders, the Reynolds number is the important flow parameter, and the Strouhal number represents the shedding frequency. These flow patterns are difficult to predict...

We report the realization of a tapered diode laser operated in a coupled ring cavity that significantly improves the coherence properties of the tapered laser and efficiently generates tunable light at the second harmonic frequency. The tapered diode laser is tunable with single-frequency output in the broad wavelength range from 1049 nm to 1093 nm and the beam propagation factor is improved fr...

In the atrophic posterior maxilla, placement of longer (at least 10 mm) and wider diameter implants may significantly improve long-term results, but sinus grafting is often necessary to provide sufficient bone volume for implant support. The crestal approach to sinus augmentation requires penetration of the sinus floor with surgical instruments that are often difficult to control; there is a hi...

We propose and derive the asymptotic distribution of a tapered narrow-band least squares estimator (NBLSE) of the cointegration parameter in the framework of fractional cointegration. This tapered estimator is invariant to deterministic polynomial trends. In particular, we allow for arbitrary linear time trends that often occur in practice. Our simulations show that, in the case of no determini...

We cooled ultrathin tapered fibers to cryogenic temperatures and controllably coupled them with high-Q microsphere resonators at a wavelength close to the optical transition of diamond nitrogen vacancy centers. The 310-nm-diameter tapered fibers were stably nanopositioned close to the microspheres with a positioning stability of approximately 10 nm over a temperature range of 7-28 K. A cavity-i...

We report one-dimensional (1-D) parabolic-beam photonic crystal (PhC) lasers in which the width of the PhC slab waveguide is parabolically tapered. A few high-Q resonant modes are confirmed in the vicinity of the tapered region where Gaussian-shaped photonic well is formed. These resonant modes originate from the dielectric PhC guided mode and overlap with the gain medium efficiently. It is als...

Vibration energy harvesting with piezoelectric materials currently generate up to 300 microwatts per cm2, using it to be mooted as an appropriate method of energy harvesting for powering low-power electronics. One of the important problems in bimorph piezoelectric energy harvesting is the generation of the highest power with the lowest weight. In this paper the effect of the shape and geometry ...