377 research outputs found

    2D InP photonic crystal fabrication process development

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    We have developed a reliable process to fabricate high quality 2D air-hole and dielectric column InP photonic crystals with a high aspect ratio on a STS production tool using ICP N2+Cl2 plasma. The photonic crystals have a triangular lattice with lattice constant of 400 nm and air-hole and dielectric column radius of 120 nm. Large efforts have been devoted on developing a proper mask. We obtained a perfect, clean and vertical profiled SiNx mask. The next main effort is InP pattern transfer in Cl 2+N2 plasma. Etching selectivity, smooth sidewall and etch profile are directly related to plasma process condition, besides the quality of SiNx mask. We have optimized the N2+Cl2 plasma condition to obtain high aspect ratio, vertical profile and smooth sidewall InP structures. Cylindrical holes (2 micron depth) and rodlike pillars (2.4 micron height) are uniformly fabricated. An aspect ratio of 18 for 100nm trench lines has been obtained. AFM measurement evidences that etched surfaces are smooth. The root mean square roughness of pillar and hole is 0.7 nm and 0.8 nm, respectively. The optical transmission characterization of ridge waveguides has been carried out. Transmission spectrum of 1 micron wide waveguide has been obtained

    A Mean-Field Theory for Coarsening Faceted Surfaces

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    A mean-field theory is developed for the scale-invariant length distributions observed during the coarsening of one-dimensional faceted surfaces. This theory closely follows the Lifshitz-Slyozov-Wagner theory of Ostwald ripening in two-phase systems [1-3], but the mechanism of coarsening in faceted surfaces requires the addition of convolution terms recalling the work of Smoluchowski [4] and Schumann [5] on coalescence. The model is solved by the exponential distribution, but agreement with experiment is limited by the assumption that neighboring facet lengths are uncorrelated. However, the method concisely describes the essential processes operating in the scaling state, illuminates a clear path for future refinement, and offers a framework for the investigation of faceted surfaces evolving under arbitrary dynamics. [1] I. Lifshitz, V. Slezov, Soviet Physics JETP 38 (1959) 331-339. [2] I. Lifshitz, V. Slyozov, J. Phys. Chem. Solids 19 (1961) 35-50. [3] C. Wagner, Elektrochemie 65 (1961) 581-591. [4] M. von Smoluchowski, Physikalische Zeitschrift 17 (1916) 557-571. [5] T. Schumann, J. Roy. Met. Soc. 66 (1940) 195-207

    Effectiveness and Feasibility of a Mindful Leadership Course for Medical Specialists

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    Background: Medical specialists experience high levels of stress. This has an impact on their well-being, but also on quality of their leadership. In the current mixed method study, the feasibility and effectiveness of a course Mindful Leadership on burnout, well-being and leadership skills of medical specialists were evaluated. Methods: This is a non-randomized controlled pre-post evaluation using self-report questionnaires administered at 3 months before (control period), start and end of the training (intervention period). Burn-out symptoms, well-being and leadership skills were assessed with self-report questionn

    Polarization tomography of metallic nanohole arrays

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    We report polarization tomography experiments on metallic nanohole arrays with square and hexagonal symmetry. As a main result, we find that a fully polarized input beam is partly depolarized after transmission through a nanohole array. This loss of polarization coherence is found to be anisotropic, i.e. it depends on the polarization state of the input beam. The depolarization is ascribed to a combination of two factors: i) the nonlocal response of the array due to surface plasmon propagation, ii) the non-plane wave nature of a practical input beam.Comment: 4 pages, 3 figures, 1 table, submitted to PR

    Study protocol of a randomized controlled trial comparing Mindfulness-Based Stress Reduction with treatment as usual in reducing psychological distress in patients with lung cancer and their partners: the MILON study

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    BACKGROUND: Lung cancer is the leading cause of cancer death worldwide and characterized by a poor prognosis. It has a major impact on the psychological wellbeing of patients and their partners. Recently, it has been shown that Mindfulness-Based Stress Reduction (MBSR) is effective in reducing anxiety and depressive symptoms in cancer patients. The generalization of these results is limited since most participants were female patients with breast cancer. Moreover, only one study examined the effectiveness of MBSR in partners of cancer patients. Therefore, in the present trial we study the effectiveness of MBSR versus treatment as usual (TAU) in patients with lung cancer and their partners. METHODS/DESIGN: A parallel group, randomized controlled trial is conducted to compare MBSR with TAU. Lung cancer patients who have received or are still under treatment, and their partners are recruited. Assessments will take place at baseline, post intervention and at three-month follow-up. The primary outcome is psychological distress (i.e. anxiety and depressive symptoms). Secondary outcomes are quality of life (only for patients), caregiver appraisal (only for partners), relationship quality and spirituality. In addition, cost-effectiveness ratio (only in patients) and several process variables are assessed. DISCUSSION: This trial will provide information about the clinical and cost-effectiveness of MBSR compared to TAU in patients with lung cancer and their partners. TRIAL REGISTRATION: ClinicalTrials.gov NCT01494883

    InP-based two-dimensional photonic crystals filled with polymers

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    Polymer filling of the air holes of Indium Phosphide based two-dimensional photonic crystals is reported. After infiltration of the holes with a liquid monomer and solidification of the infill in situ by thermal polymerization, complete filling is proven using scanning electron microscopy. Optical transmission measurements of a filled photonic crystal structure exhibit a redshift of the air band, confirming the complete filling.Comment: To be published in Appl. Phys. Let

    Gender and Context Matter: Behavioral and Structural Interventions for People Who Use Alcohol and Other Drugs in Africa

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    Heavy alcohol consumption and other drug use are prominent across Africa and increase the risk of exposure to violence, HIV acquisition, and other life-threatening injuries. This review synthesizes evidence on alcohol and other drug (AOD) interventions in Africa; evaluates the differences between interventions that do and do not specifically target populations that use AODs; and highlights the impact of comprehensive vs. brief interventions and those that address syndemic issues from a gender and contextualized lens. Literature searches were conducted to identify research outcomes of randomized interventions published between January 2010 and May 2022 that address AOD use in Africa. Thirty-five full-text articles were included in this review. Most of the identified research studies were concentrated in a few countries. Most studies were conducted in South Africa. Many of the studies comprised brief interventions. However, the most comprehensive interventions were the most effective for AOD outcomes. Several studies indicated the importance of addressing AOD use alongside gender-based violence, mental health needs, gender roles, and other social determinants that affect health outcomes. Intervening on AOD use and addressing social determinants from a gender and contextually relevant perspective is essential to ensuring the long-term health and well-being of people in Africa
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