RESUMEN
Sintering of metal nanowire (NW) networks on transparent polymers is an emerging approach for fabricating transparent conductive electrodes used in multiple devices. Pulsed light sintering is a scalable sintering process in which large-area, broad-spectrum xenon lamp light causes rapid NW fusion to increase network conductivity, while embedding the NWs in the polymer to increase mechanical robustness. This paper develops a multiphysical approach for predicting evolution of conductivity, NW fusion and nanoscale temperature gradients on the substrate during pulsed light sintering of silver NWs on polycarbonate. Model predictions are successfully validated against experimentally measured temperature and electrical resistance evolution. New insight is obtained into the diameter-dependent kinetics of NW fusion and nanoscale temperature gradients on the substrate, which are difficult to obtain experimentally. These observations also lead to the understanding that NW embedding in intense pulsed light sintering (IPL) can occur below the glass transition temperature of the polymer, and to a new differential thermal expansion-based mechanism of NW embedding during IPL. These insights, and the developed model, create a framework for physics-guided choice of NWs, substrate and process parameters to control conductivity and prevent substrate damage during the process.
RESUMEN
We examine the electromagnetic emission from two photo-illuminated linear arrays composed of inductively charged superconducting ring elements. The arrays are illuminated by an ultrafast infrared laser that triggers microwave broadband emission detected in the 1-26 GHz range. Based on constructive interference from the arrays a narrowing of the forward radiation lobe is observed with increasing element count and frequency demonstrating directed GHz emission. Results suggest that higher frequencies and a larger number of elements are achievable leading to a unique pulsed array emitter concept that can span frequencies from the microwave to the terahertz (THz) regime.
RESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMEN
Intense Pulsed Light sintering (IPL) uses pulsed, visible light to sinter nanoparticles (NPs) into films used in functional devices. While IPL of chalcogenide NPs is demonstrated, there is limited work on prediction of crystalline phase of the film and the impact of optical properties of the substrate. Here we characterize and model the evolution of film temperature and crystalline phase during IPL of chalcogenide copper sulfide NP films on glass. Recrystallization of the film to crystalline covellite and digenite phases occurs at 126 °C and 155 °C respectively within 2-7 seconds. Post-IPL films exhibit p-type behavior, lower resistivity (~10-3-10-4 Ω-cm), similar visible transmission and lower near-infrared transmission as compared to the as-deposited film. A thermal model is experimentally validated, and extended by combining it with a thermodynamic approach for crystal phase prediction and via incorporating the influence of film transmittivity and optical properties of the substrate on heating during IPL. The model is used to show the need to a-priori control IPL parameters to concurrently account for both the thermal and optical properties of the film and substrate in order to obtain a desired crystalline phase during IPL of such thin films on paper and polycarbonate substrates.
RESUMEN
Although co-payments and deductibles are means of keeping health expenditures low, they have also been cited as barriers that inhibit patients from accessing necessary healthcare. We aimed to evaluate Rhode Island residents' experiences with cost-related access challenges within the state's healthcare system. We conducted a cross-sectional survey of resident experiences with healthcare in Rhode Island. Our survey instrument was composed of the RAND Corporation "Short-Form Patient Satisfaction Questionnaire (PSQ-18)", questions developed by the Rhode Island Office of the Health Insurance Commissioner, and ranking of health priorities based on prior community assessments conducted by the Rhode Island Department of Health. Data were collected at venues across the state as part of the Rhode Island Department of Health 2015 Statewide Health Inventory. From July to August 2015, 404 surveys were completed. We found that 40% of respondents had a co-pay of $20-$50, while 35.7% of respondents had a deductible of greater than $500. Further, one-third of respondents delayed receiving care due to financial barriers. This decision resulted in a worsening condition or hospital visit for nearly half of those respondents. Co-pays and deductibles pose challenges to Rhode Islanders accessing health care. Cost-related barriers to healthcare access should continue to be addressed, especially in the context of preventive care services, which are now being built into health insurance premiums through the Patient Protection and Affordable Care Act. [Full article available at http://rimed.org/rimedicaljournal-2016-11.asp].