The propagation of chemical waves in the photosensitive Belousov-Zhabotinsky (BZ) reaction was investigated using an excitable field in the shape of a circular ring or figure "8" that was drawn by computer software and then projected on a film soaked with BZ solution using a liquid-crystal projector. For a chemical wave in a circular reaction field, the shape of the chemical wave was investigated depending on the ratio of the inner and outer radii. When two chemical waves were generated on a field shaped like a figure "8" (one chemical wave in each circle) as the initial condition, the location of the collision of the waves either was constant or alternated depending on the degree of overlap of the two circular rings. These experimental results were analyzed on the basis of a geometrical discussion and theoretically reproduced on the basis of a reaction-diffusion system using a modified Oregonator model. These results suggest that the photosensitive BZ reaction may be useful for creating spatio-temporal patterns depending on the geometric arrangement of excitable fields.
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http://dx.doi.org/10.1021/jp0507905 | DOI Listing |
ACS Nano
January 2025
Shanghai Key Laboratory of Chemical Assessment and Sustainability, School of Chemical Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, China.
The synthesis of covalent organic frameworks (COFs) with excellent luminescent properties and their effective application in the field of bionic sensing remain a formidable challenge. Herein, a series of COFs with different numbers of hydroxyl groups are successfully synthesized, and the number of hydroxyl groups on the benzene-1,3,5-tricarbaldehyde (BTA) linker influences the properties of the final COFs. The COF (HHBTA-OH) prepared with hydrazine hydrate (HH) and BTA containing one hydroxyl group as the ligands exhibits the best fluorescent performance.
View Article and Find Full Text PDFUltrason Sonochem
January 2025
State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, China; Light Alloy Research Institute, Central South University, Changsha 410083, China.
The chemical corrosion of the TC4 radiation rod surface (TRRS) during the ultrasonic casting process has the potential to significantly impair the smooth conduction of ultrasonic waves. However, in the later stages of corrosion, a self-protected structure (TSPS) emerges under the ultrasonic cavitation effect, which serves to impede the chemical corrosion of the TRRS and markedly reduce the rate of mass loss of the radiation rod. This ensures the smooth ultrasonic conduction of the radiation rod during operation.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Department of Mechanics of Materials and Constructions (MeMC), Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
There is very limited research in the literature investigating the way acoustic emission signals change when polymer materials are undergoing different fracture modes. This study investigates the capability of acoustic emission to recognize the fracture mode through acoustic emission parameter analysis, and can be considered the first-ever study which examines the impact of different loading conditions, i.e.
View Article and Find Full Text PDFPLoS Comput Biol
January 2025
Department of Mechanical Engineering & Materials Science, Washington University, St. Louis, Missouri, United States of America.
Cell collectives, like other motile entities, generate and use forces to move forward. Here, we ask whether environmental configurations alter this proportional force-speed relationship, since aligned extracellular matrix fibers are known to cause directed migration. We show that aligned fibers serve as active conduits for spatial propagation of cellular mechanotransduction through matrix exoskeleton, leading to efficient directed collective cell migration.
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Mechanical Engineering, Clemson University, Clemson, SC 29634, USA.
Instabilities in the form of periodic or irregular waves at the fluid interface have been demonstrated in microchannel electrokinetic flows with conductivity gradients when the applied electric field is above a threshold value. Most prior studies on electrokinetic instabilities (EKI) are restricted to Newtonian fluids though many of the chemical and biological samples in microfluidic applications exhibit non-Newtonian characteristics. We present in this work an experimental study of the effects of fluid shear thinning on the development of EKI waves through the addition of a small amount of xanthan gum (XG) polymer to both the high- and low-concentration Newtonian buffer solutions.
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