High coupling efficiency to a low dispersion slow light-supporting photonic crystal waveguide

In this paper, we design a waveguide on photonic crystal slab for propagation of low-dispersion slow light. By shifting the air holes adjacent to the waveguide, we obtain a photonic crystal waveguide with a group index of 25 in 25 nm bandwidth which results in a group index bandwidth product of 0.366. To take the advantages of low dispersion slow light generated in this engineered waveguide, we next focus on low coupling efficiency limitation. A low group index coupler is proposed to increase the transmission of the light to the slow mode in the low dispersion bandwidth. By using the proposed coupler and adjusting the structural parameters, the coupling efficiency to low dispersion slow light is improved 11 dB compared to the transmission without the coupler

Miniaturized Metamaterial Filters Compatible with Standard Waveguide Technology

In this paper, we study the behavior of miniaturized high-order waveguide filters, constructed by loading a hollow metallic waveguide with resonant pins, to form a locally-resonant metamaterial. Such composite pin-pipe structure supports a guided-mode with adjustable bandwidth below the resonance frequency of the pins. We show that the position and bandwidth of this sub-wavelength mode are decoupled from the arrangement of resonant inclusions. We experimentally demonstrate the customizability of the bandwidth and the robustness of the passband against geometrical scaling. Our prototypes, which are an order of magnitude smaller and lighter than traditional filters and compatible with standard waveguide ports, may find applications in future satellite systems, for 5G or internet over satellite technologies

A knowledge map for hospital performance concept: Extraction and analysis: A narrative review article

Background: Performance is a multi-dimensional and dynamic concept. During the past 2 decades, considerable studies were performed in developing the hospital performance concept. To know literature key concepts on hospital performance, the knowledge visualization based on co-word analysis and social network analysis has been used. Methods: Documents were identified through �PubMed� searching from1945 to 2014 and 2350 papers entered the study after omitting unrelated articles, the duplicates, and articles without abstract. After pre-processing and preparing articles, the key words were extracted and terms were weighted by TF-IDF weighting schema. Support as an interestingness measure, which considers the co-occurrence of the extracted keywords and "hospital performance" phrase was calculated. Keywords having high support with "hospital performance" are selected. Term-term matrix of these selected keywords is calculated and the graph is extracted. Results: The most high frequency words after �Hospital Performance� were �mortality� and �efficiency�. The major knowledge structure of hospital performance literature during these years shows that the keyword �mortality� had the highest support with hospital performance followed by �quality of care�, �quality improvement�, �discharge�, �length of stay� and �clinical outcome�. The strongest relationship is seen between �electronic medical record� and �readmission rate�. Conclusion: Some dimensions of hospital performance are more important such as �efficiency�, �effectiveness�, �quality� and �safety� and some indicators are more highlighted such as �mortality�, �length of stay�, �readmission rate� and �patient satisfaction�. In the last decade, some concepts became more significant in hospital performance literature such as �mortality�, �quality of care� and �quality improvement�. © 2016, Iranian Journal of Public Health. All rights reserved