Transmission diffraction gratings operating at 1,565 nm based on multilayer porous silicon films are modeled, fabricated, and tested. Features down to 2 μm have been patterned into submicron-thick mesoporous films using standard photolithographic and dry etching techniques. After patterning of the top porous film, a second anodization can be performed, allowing an under-layer of highly uniform porosity and thickness to be achieved. High transmission greater than 40% is measured, and modeling results suggest that a change in diffraction efficiency of 1 dB for a 1% change in normalized refractive index can be achieved. Preliminary measurement of solvent vapor shows a large signal change from the grating sensor in agreement with models.
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http://dx.doi.org/10.1186/1556-276X-7-645 | DOI Listing |
ACS Omega
January 2025
Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.
We report a new approach for fabricating gate-tunable thermal emissivity surfaces by spraying them on graphene ink. The devices consist of a multilayer graphene (MLG)/porous alumina membrane/gold stack, in which the MLG is deposited by spraying the graphene ink onto the porous membrane using an airbrush. The graphene ink consists of μm-sized flakes of MLG suspended in a solution of polyvinylpyrrolidone and ethylene glycol.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Textile Innovation R&D Department, Korea Institute of Industrial Technology, Ansan 15588, Republic of Korea. Electronic address:
Artificial vascular grafts, as blood vessel substitutes, are a prime challenge in tissue engineering and biomaterial research. An ideal artificial graft must have physiological and mechanical properties similar to those of a natural blood vessel, and hemocompatibility on its surface. We designed and fabricated artificial grafts by applying 3D printing and templated technology, which is endowed with morphologically patient-specific vascular reconstruction.
View Article and Find Full Text PDFThis paper explores the process of forming arrays of vertically oriented carbon nanotubes (CNTs) localized on metal electrodes using thin porous anodic alumina (PAA) on a solid substrate. On a silicon substrate, a titanium film served as the electrode layer, and an aluminium film served as the base layer in the initial film structure. A PAA template was formed from the Al film using two-step electrochemical anodizing.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Mechanical Engineering, Qom University of Technology, Qom, 37195-1519, Iran.
This study investigates the use of multi-layered porous media (MLPM) to enhance thermal energy transfer within a counterflow double-pipe heat exchanger (DPHE). We conducted computational fluid dynamics (CFD) simulations on DPHEs featuring five distinct MLPM configurations, analyzed under both fully filled and partially filled conditions, alongside a conventional DPHE. The impact of various parameters such as porous layer arrangements, thickness, and flow Reynolds numbers on pressure drop, logarithmic mean temperature difference (LMTD), and performance evaluation criterion (PEC) was assessed.
View Article and Find Full Text PDFJ Funct Biomater
December 2024
Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Surgery is considered the gold standard for treating melanoma, but the high recurrence rate after surgery still remains as a major challenge. Therefore, using doxorubicin (DOX) as a model drug, this study investigated the 3D printing of anticancer drug-loaded hydrogel blend scaffolds for inhibiting post-operation melanoma recurrence and for promoting tissue regeneration. Three-dimensional printing could successfully produce methacrylate-modified chitosan (CSMA) and methylcellulose (MC) hydrogel blend scaffolds.
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