An equilibrium random surface multistep height model proposed in [Abraham and Newman, EPL 86, 16002 (2009)] is studied using a variant of the worm algorithm. In one limit, the model reduces to the two-dimensional Ising model in the height representation. When the Ising model constraint of single height steps is relaxed, the critical temperature and critical exponents are continuously varying functions of the parameter controlling height steps larger than one. Numerical estimates of the critical exponents can be mapped via a single parameter, the Coulomb gas coupling, to the exponents of the O(n) loop model on the honeycomb lattice with n ≤ 1.
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http://dx.doi.org/10.1103/PhysRevE.85.061104 | DOI Listing |
Micromachines (Basel)
January 2025
School of Physics and Optoelectronic Engineering, Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China.
To enhance the end-face coupling efficiency of lithium niobate on insulator (LNOI) chips, in conjunction with current device fabrication processes, a stepped spot size converter (SSC) based on a special outer envelope profile has been proposed and investigated. This stepped SSC can reduce the coupling loss between the LNOI waveguide and a normal single-mode optical fiber. First, the output waveguide of a mode converter was proposed and simulated, in which the mode field had the biggest overlapping integral factor with a single-mode fiber (MDF ≈ 9.
View Article and Find Full Text PDFMicromachines (Basel)
January 2025
DTU Nanolab, National Centre for Nano Fabrication and Characterization, Technical University of Denmark, Ørsteds Plads B347, 2800 Kongens Lyngby, Denmark.
A wafer-scale process for fabricating monolithically suspended nano-perforated membranes (NPMs) with integrated support structures into silicon is developed. Existing fabrication methods are suitable for many desired geometries, but face challenges related to mechanical robustness and fabrication complexity. We demonstrate a process that utilizes the cyclic deposit, remove, etch, and multi-step (DREM) process for directional etching of high-aspect-ratio (HAR) 300 nm in diameter nano-pores of 700 nm pitch.
View Article and Find Full Text PDFJ Mater Chem B
December 2024
School of Physics, University of Sydney, Sydney, NSW 2006, Australia.
Polymeric nanoparticles surface functionalised with fluorescent molecules hold significant potential for advancing diagnostics and therapeutic delivery. Despite their promise, challenges persist in achieving robust attachment of fluorescent molecules for real-time tracking. Weak physical adsorption, pH-dependent electrostatic capture, and hydrophobic interactions often fail to achieve stable attachment of fluorescent markers.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Crystallography & Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata 700064, India.
The artificial metalloenzyme containing iridium in place of iron along with four directed evolution mutations C317G, T213G, L69V, and V254L in a natural cytochrome P450 presents an important milestone in merging the extraordinary efficiency of biocatalysts with the versatility of small molecule chemical catalysts in catalyzing a new-to-nature carbene insertion reaction. This is a show-stopper enzyme, as it exhibits a catalytic efficiency similar to that of natural enzymes. Despite this remarkable discovery, there is no mechanistic and structural understanding as to why it displays extraordinary efficiency after the incorporation of the four active site mutations by directed evolution methods, which so far has been intractable to any experimental methods.
View Article and Find Full Text PDFSci Rep
November 2024
Department of Pathology, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia.
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