The control of a nanometer-wide gap between tip and substrate is critical for nanoscale applications of scanning electrochemical microscopy (SECM). Here, we demonstrate that the stability of the nanogap in ambient conditions is significantly compromised by the thermal expansion and contraction of components of an SECM stage upon a temperature change and can be dramatically improved by suppressi...

The volume created by the positioning of two scanning electrochemical microscope (SECM) probes (tip and substrate) at a micrometric distance defines a "picoliter beaker" where homogeneous electron-transfer reactions are studied. The SECM is used to concurrently electrogenerate in situ two reactive species and to evaluate the possibility of detecting their reactivity. Two reaction cases are stud...

We report the crucial components required to perform scanning electrochemical microscopy (SECM) with nanometer-scale resolution. The construction and modification of the software and hardware instrumentation for nanoscale SECM are explicitly explained including (1) the LabVIEW code that synchronizes the SECM tip movement with the electrochemical response, (2) the construction of an isothermal c...

The short-lived intermediate N,N-dimethylaniline (DMA) cation radical, DMA(•+), was detected during the oxidation of DMA in MeCN with 0.1 M tetra-n-butylammonium hexafluorophosphate. The detection was accomplished at steady state by scanning electrochemical microscopy (SECM) with ultramicroelectrodes using the tip generation/substrate collection mode. Cyclic voltammetry (CV) with a 2 mm Pt elec...

The tip-clearance size of compressor rotors has a big effect on both performance and off-design conditions. Increasing the value tip gap can lead to reduction in efficiency surge margin about 1 %. Mechanical constraints impose minimal clearance order for operate while further would generally be beneficial aerodynamically. However, sensitivity show more complex tendencies. For example, some stud...

It is difficult to predict the measurement bias arising from the compliance of the atomic force microscope (AFM) probe. The issue becomes particularly important in this situation where nanometer uncertainties are sought for measurements with dimensional probes composed of flexible carbon nanotubes mounted on AFM cantilevers. We have developed a finite element model for simulating the mechanical...

BACKGROUND AND AIMS Most studies of exodermal structure and function have involved species with a uniseriate exodermis. To extend this work, the development and apoplastic permeability of Iris germanica roots with a multiseriate exodermis (MEX) were investigated. The effects of different growth conditions on MEX maturation were also tested. In addition, the exodermises of eight Iris species wer...

We have shown previously that conductance of rat liver gap junctions is blocked by an affinity-purified polyclonal antibody generated against rat liver junctional membranes, is not affected by moderate transjunctional or transmembrane potentials, and is reversibly decreased by cytoplasmic acidification and perfusion with octanol. We have now recorded currents from isolated liver gap junctions u...