A two step process has been developed for the fabrication of diffraction limited concave microlens arrays. The process is based on the photoresist filling of melted holes obtained by a preliminary photolithography step. The quality of these microlenses has been tested in a Mach-Zehnder interferometer. The method allows the fabrication of concave microlens arrays with diffraction limited optical performance. Concave microlenses with diameters ranging between 30 microm to 230 microm and numerical apertures up to 0.25 have been demonstrated. As an example, we present the realization of diffusers obtained with random sizes and locations of concave shapes.
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http://dx.doi.org/10.1364/oe.16.019541 | DOI Listing |
Langmuir
December 2024
Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India.
Widespread geogenic uranium (U) contamination of Indian groundwaters is of serious concern; yet little is known of the dominant forms and release mechanisms of U in these aquifers. Interestingly, manganese (Mn)-rich aquifers, highly buffered by dissolved inorganic carbon (DIC) and saturated with rhodochrosite [MnCO], have shown low U (
Nanomaterials (Basel)
December 2024
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, ul. Grudziądzka, 5, 87-100 Toruń, Poland.
In this work, we present an experimental approach for monitoring the temperature of submicrometric, real-time operating electrical circuits using luminescence thermometry. For this purpose, we utilized lanthanide-doped up-converting nanocrystals as nanoscale temperature probes, which, combined with a highly sensitive confocal photoluminescence microscope, enabled temperature monitoring with spatial resolution limited only by the diffraction of light. To validate our concept, we constructed a simple model of an electrical microcircuit based on a single silver nanowire with a diameter of approximately 100 nm and a length of about 50 µm, whose temperature increase was induced by electric current flow.
View Article and Find Full Text PDFGels
November 2024
Biomedical Engineering Department, Saint Louis University, Saint Louis, MO 63103, USA.
Biological agents such as extracellular vesicles (EVs) and growth factors, when administered in vivo, often face rapid clearance, limiting their therapeutic potential. To address this challenge and enhance their efficacy, we propose the electrostatic conjugation and sequestration of these agents into gelatin-based biomaterials. In this study, gelatin nanoparticles (GNPs) were synthesized via the nanoprecipitation method, with adjustments to the pH of the gelatin solution (4.
View Article and Find Full Text PDFInt J Comput Assist Radiol Surg
December 2024
High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan.
Purpose: In this paper, we describe an algebraic reconstruction algorithm with a total variation regularization (ART + TV) based on the Superimposed Wavefront Imaging of Diffraction-enhanced X-rays (SWIDeX) method to effectively reduce the number of projections required for differential phase-contrast CT reconstruction.
Methods: SWIDeX is a technique that uses a Laue-case Si analyzer with closely spaced scintillator to generate second derivative phase-contrast images with high contrast of a subject. When the projections obtained by this technique are reconstructed, a Laplacian phase-contrast tomographic image with higher sparsity than the original physical distribution of the subject can be obtained.
J Am Chem Soc
December 2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China.
The exploration of main group compounds with multiple bonds has significantly enhanced our understanding of chemical bonding and expanded transition-metal-free bond activation and catalysis. Diborynes, characterized by a boron-boron triple bond (B≡B), represent a particularly challenging area due to boron's limited valence electrons. Here, we report the synthesis and characterization of a silylene-stabilized diboryne (), expanding the frontier of diboryne stabilization.
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