1,273 research outputs found
Nanogratings Formation in a System of Ultra-short Laser Pulses – Metalloorganic Gas – Deposited Metal – Sapphire in Sinergetic Interference Field with Waveguide Modes Participation
Experimental results of laser-induced deposition of structured metal films from metalloorganic vapor have been analyzed. A new physical model has been put forward to explain the results. The model is based on the interference phenomena between the incident laser radiation and waveguide modes of a thermally induced gradient waveguide in the substrate.
Keywords: femtosecond radiation, metal deposition, interference, waveguide modes, surface nanogratings
Measurement of pressure and assessment of cavitation for a 22.5-kHz intra-arterial angioplasty device
This study was performed to understand better the mechanisms of action of an (22.5 kHz) ultrasonic wire catheter device used to remove atheromatous plaque in diseased blood vessels (ultrasonic angioplasty). During a clinical procedure, the wire acts as an acoustic waveguide to transfer acoustic energy from a generator outside the body to the ball tip of the wire, which is inserted in the blood vessel. The acoustic field radiated by the vibrating ball tip (1.5- to 3.0-mm diameter), was mapped in a relatively large (600 L) water tank and compared to the field from a well-characterized simple source. A dipolelike radiation pattern due to the translating ball tip was observed. At low power settings, standing wave effects in a smaller cylindrical volume (200-mm diameter, 350-mm height), which was used to simulate anthropometric dimensions, increase relative to the larger tank measurements. The standing wave ratio is dependent upon the pc characteristics of the medium and the dimensions of the volume, rather than on the absorption at this frequency. At high power-settings of the device, cavitation at the tip of the wire was measured using a 20-MHz passive cavitation detection scheme
A Preliminary Survey on Islamic Mysticism in Java
Berbagai praktik mistik telah berkembang di kalangan masyarakat Jawa. Kemunculan praktik tersebut sebenarnya dapat dilacak dari konteks sejarah masuknya Islam ke Indonesia, dan Jawa pada khususnya. Artikel ini bertujuan untuk mengeksplorasi Islam dan mistisime di Jawa, yakni menjelaskan rasionalitas dari penerimaan komunitas Muslim atas penyebaran mistisisme Islam dan penyebaran mistisisme Islam itu sendiri di Jawa. Penelitian ini menyimpulkan bahwa mistisime Jawa tumbuh subur dalam hampir setiap sendi kehidupan; di lingkungan keluarga istana, pesantren, grup kebatinan, dan di tingkat publik secara umum. Hal ini terjadi karena Islam yang sebenarnya diperkenalkan ke Indonesia dan Jawa, khususnya, adalah Islam yang dirumuskan sebagai Islam mistik. Mistisisme Islam lebih mudah berkembang sebagaimana ia juga dapat menyesuaikan diri dengan pemahaman pubik masyarakat Jawa
Convergence of eigenfunction expansions corresponding to nonlinear Sturm-Liouville operators
It is well known that the classical linear Sturm-Liouville eigenvalue problem is self-adjoint and possesses a family of eigenfunctions which form an orthonormal basis for the space L. A natural question is to ask if a similar result holds for nonlinear problems. In the present paper, we examine the basis property for eigenfunctions of nonlinear Sturm-Liouville equations subject to general linear, separated boundary conditions
Soft Embodiment for Engineering Artificial Limbs
We highlight two alternative, yet complementary, solutions for harnessing available neural resources for improving integration of artificial limbs (ALs) through embodiment. ‘Hard’ embodiment exploits neural and cognitive body mechanisms by closely mimicking their original biological functions. ‘Soft’ embodiment exploits these same mechanisms by recycling them to support a different function altogether
Spin-guides and spin-splitters: Waveguide analogies in one-dimensional spin chains
Here we show a direct mapping between waveguide theory and spin chain
transport, opening an alternative approach to quantum information transport in
the solid-state. By applying temporally varying control profiles to a spin
chain, we design a virtual waveguide or 'spin-guide' to conduct individual spin
excitations along defined space-time trajectories of the chain. We explicitly
show that the concepts of confinement, adiabatic bend loss and beamsplitting
can be mapped from optical waveguide theory to spin-guides (and hence
'spin-splitters'). Importantly, the spatial scale of applied control pulses is
required to be large compared to the inter-spin spacing, and thereby allowing
the design of scalable control architectures.Comment: 5 figure
YSO jets in the Galactic plane from UWISH2 – III. Jets and outflows in Cassiopeia and Auriga
We present the analysis of 35.5 deg2 of images in the 1–0 S(1) line of H2 from the UK Widefield Infrared Survey for H2 (UWISH2) towards Cassiopeia and Auriga. We have identified 98 Molecular Hydrogen emission-line Objects (MHOs) driven by Young Stellar Objects, 60 per cent of which are bipolar outflows and all are new discoveries. We estimate that the UWISH2-extended emission object catalogue contains fewer than 2 per cent false positives and is complete at the 95 per cent level for jets and outflows brighter than the UWISH2 detection limit. We identified reliable driving source candidates for three quarters of the detected outflows, 40 per cent of which are associated with groups and clusters of stars. The driving source candidates are 20 per cent protostars, the remainder are Classical T-Tauri Stars. We also identified 15 new star cluster candidates near MHOs in the survey area. We find that the typical outflow identified in the sample has the following characteristics: the position angles are randomly orientated; bipolar outflows are straight within a few degrees; the two lobes are slightly asymmetrical in length and brightness; the length and brightness of the lobes are not correlated; typical time gaps between major ejections of material are 1–3 kyr, hence FU-Ori or EX-Ori eruptions are most likely not the cause of these, but we suggest MNors as a possible source. Furthermore, we find that outflow lobe length distributions are statistically different from the widely used total length distributions. There are a larger than expected number of bright outflows indicating that the flux distribution does not follow a power law
Quantum phase transitions in photonic cavities with two-level systems
Systems of coupled photonic cavities have been predicted to exhibit quantum
phase transitions by analogy with the Hubbard model. To this end, we have
studied topologies of few (up to six) photonic cavities each containing a
single two-level system. Quantum phase space diagrams are produced for these
systems, and compared to mean-field results. We also consider finite effective
temperature, and compare this to the notion of disorder. We find the extent of
the Mott lobes shrink analogously to the conventional Bose-Hubbard model.Comment: 11 pages, 11 figures, updated typo
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