Capillary-Induced Wrinkle-to-Fold Transitions Under Biaxial Compression.

Wrinkles in bilayer systems comprising a thin stiff film attached to a soft substrate can globally transition into folds under sufficiently large compression. This phenomenon has been extensively studied primarily using uniaxially compressed systems. However, inducing the wrinkle-to-fold transition at designated locations on a wrinkled surface under small biaxial compression remains a challenge.

Unlocalized crack initiation and propagation in staggered biomaterials.

Many types of tissues in living organisms exhibit a combination of different properties to fulfil their mechanical functions in complex environments. Nacre with more than 90% brittle and hard phase and a little protein matrix, exhibits high strength and toughness, which is difficult to achieve in artificial materials. Researchers have shown that the toughness of nacre is related to the cracking process.

Manganese-mediated C3-selective direct alkylation and arylation of 2-pyridones with diethyl malonates and arylboronic acids.

A manganese-mediated dehydrogenative direct alkylation of 2-pyridones with diethyl malonates has been developed. A similar reaction system is applicable to the direct arylation with arylboronic acids. These manganese-based reactions occur regioselectively at the C3 position of the 2-pyridones.

Nickel-catalyzed direct alkylation of heterocycles with α-bromo carbonyl compounds: C3-selective functionalization of 2-pyridones.

Nickel HAS it: A Ni(cod)2/dppp catalyst system promotes the direct alkylation of electron-rich heterocycles with α-bromo carbonyl compounds and involves an alkyl radical intermediate (see scheme; cod = 1,5-cyclooctadiene, dppp = 1,3-bis(diphenylphosphino)propane). This homolytic radical aromatic substitution (HAS)-type reaction enables the C3-selective direct functionalization of 2-pyridones.

A concise access to (polyfluoroaryl)allenes by Cu-catalyzed direct coupling with propargyl phosphates.

A copper-based catalyst system for the direct coupling of polyfluoroarenes with propargyl phosphates has been developed. The catalysis can provide a rapid and concise access to (polyfluoroaryl)allenes, which can be important building blocks for the synthesis of fluorinated functional materials.

Modulational instability of zone boundary mode and band edge modes in nonlinear diatomic lattices.

We analyze the modulational instability of the zone boundary mode (ZBM) and the band edge modes (BEMs) in a one-dimensional nonlinear diatomic lattice and obtain rigorous results. Some numerical calculations of modulational instability in these modes are presented. These results indicate that the modulational instability of the BEMs leads to excitation of the discrete breathers (DBs) in the band gap, while that of the ZBM leads to excitation of the DBs above the phonon band.

Refolding of fully reduced bovine pancreatic trypsin.

Refolding of bovine pancreatic trypsin was carried out. When starting with denatured S-S intact trypsin, the recovered activity attained was 95-100%. In contrast, the recovered activity after refolding denatured S-S reduced trypsin was considerably low compared with other proteases that have been worked with previously.

Hydrogen bond dynamics and microscopic structure of confined water inside carbon nanotubes.

We have investigated the density and temperature dependences of microscopic structure and hydrogen bond dynamics of water inside carbon nanotubes (CNTs) using molecular dynamics simulation. The CNTs are treated as rigid, and smoothly truncated extended simple point charge water model is adopted. The results show that as the overall density increases, the atomic density profiles of water inside CNTs become sharper, the peaks shift closer to the wall, and a new peak of hydrogen atomic density appears between the first (outermost) and second layer.

Flow structure of water in carbon nanotubes: poiseuille type or plug-like?

We have conducted molecular dynamics simulations of water flow in carbon nanotubes (CNTs) for (6,6) to (20,20) CNTs at a streaming velocity of 100 ms. The fluidized piston model (FPM) and the ice piston model (IPM) are employed to drive flow through the CNTs. The results show that the single-file water flow inside (6,6) CNT has a convex upward streaming velocity profile, whereas the velocity profiles in (10,10) to (20,20) CNTs are flat except near the tube wall.