Effects of two types of surface treatments on the structural elasticity of human fingernails.

Background: The human nail has a three-layered structure. Although it would be useful to quantitatively evaluate the changes in deformability of the nail due to various surface treatments, few studies have been conducted.

Methods: The effects of two types of surface treatment-a chemically acting nail softener and a physically acting nail strengthener-on the deformability of human fingernails were investigated.

Nanostructure-Based Solution Sensor Fabricated with -CuO/-TiO Nanojunctions To Identify Species and Concentrations of Alcohol Molecules.

Chemiresistive sensors fabricated based on metal-oxide-semiconductors, the most widely used high-sensitivity sensor materials, are required for detecting target solutions and gases and identifying them with a high degree of accuracy. In this study, we used - nanojunctions and nanowire shapes for identifying alcohol solutions. The solution sensors fabricated based on CuO nanowires with -CuO/-TiO nanojunctions detected ethanol, ethylene glycol, and diethylene glycol solutions via DC voltage and electrochemical impedance measurements.

Nanoindentation study of human fingernail for determining its structural elasticity.

Background: Human nails play an important role in transmitting force to the fingertips, and their mechanical properties are important indices. The nail has a three-layered structure consisting of top dorsal, middle intermediate, and under ventral plates, and its internal structure is believed to affect its mechanical properties. However, this has not been investigated in previous studies.

Copper Oxide Solution Sensor Formed on a Thin Film Having Nanowires for Detecting Ethanol in Water.

Solution sensors are required to detect analytes in liquids with high sensitivity and response speed for environmental and health monitoring. In this study, we introduce the concept of a Cu oxide thin film having nanowires as a solution sensor for detecting ethanol in water. The Cu oxide sensor with grains and nanowires of different shapes was fabricated by a simple method of heating a Cu thin film and dropping an Ag conductive paste.

Division of force among layers constituting human hair during bending and tension.

Human hair is a three-layered structure comprising the inner medulla, middle cortex, and outer cuticle layer. When a hair is subjected to bending or tensile load, each of these layers absorbs a certain amount of the force applied. However, the magnitude of the force absorbed by each layer is not easy to estimate.

Acoustic resonant imaging technique for visualizing the acoustic properties and thickness of polymer film on substrate.

This paper proposes an acoustic resonant imaging technique for visualizing the acoustic properties and thickness of a polymer film on a substrate. When ultrasound passes through a thin layer, transmission and reflection coefficients of sound pressure attain their extreme values at the resonant frequency. By obtaining the area information of the extreme value and resonant frequency and matching them with a theoretical model, the acoustic properties and thicknesses of a polymer film on a substrate can be visualized.

Structural elasticity for tensile deformation of a single human hair and the comparison with it for the bending deformation.

Human hair is a multi-layered structure, which consists of the inner medulla, middle cortex, and outer cuticle. Therefore, the mechanical properties of the hair are related not only to the Young's modulus of each layer but also to the internal structures. Although the tensile test of a human hair has been performed elsewhere, the deformability of the hair for the tensile deformation is determined as the Young's modulus of the hair structure, which is similar to that of metals.

Interfacial Contact Behavior between CNTs and AgNW with Molecular Dynamics Simulation.

The behavior at an interface between carbon nanotubes (CNTs) and silver nanowire (AgNW) could hardly be observed experimentally on an atomic scale, and the interaction is difficult to accurately calculate due to nanometer size effects. In this work, the contact behavior is studied with the molecular dynamics (MD) simulation, which indicates that the CNTs and AgNW can move towards each other to form aligned structures with their interfaces in full contact. In these different composite systems, nanotubes may either keep their form of an inherent cylindrical structure or completely collapse into the nanoribbons that can tightly scroll on the AgNW periphery while wrapping it in a core-shell structure.

On the correlation between the curvature of the human eyelash and its geometrical features.

Unlabelled: Although human eyelashes are generally curved, the cause of the natural curvature of eyelashes has not yet to be clarified elsewhere. Related with this, this paper reports our discovery of a correlation between the curvature of the eyelash and its geometrical features. Eyelashes can be divided into root, middle and tip sections.

Determination of acoustic properties of thin polymer films utilizing the frequency dependence of the reflection coefficient of ultrasound.

This paper reports on a technique to measure the acoustic properties of a thin polymer film utilizing the frequency dependence of the reflection coefficient of ultrasound reflected back from a system comprising a reflection plate, the film, and a material that covers the film. The frequency components of the echo reflected from the back of the plate, where the film is attached, take their minimum values at the resonant frequency, and from these frequency characteristics, the acoustic impedance, sound velocity, and the density of the film can be determined. We applied this technique to characterize an ion exchange membrane, which has high water absorbability, and successfully determined the acoustic properties of the membrane without getting it wet.

Acoustic study of a linear low-density polyethylene film after modification of the crystalline structure by heating.

We report on a hybrid microscopy technique that enables us to measure the acoustic properties of a thin polymer film together with an optical microscope image of the corresponding area. Linear low-density polyethylene films are heated to various temperatures and examined by the technique. Density of the film is increased by heating and its sound velocity is decreased compared with a film without heating.

Numerical analysis of the electrical failure of a metallic nanowire mesh due to Joule heating.

To precisely examine the electrical failure behavior of a metallic nanowire mesh induced by Joule heating (i.e., melting), a previously developed numerical method was modified with regard to the maximum temperature in the mesh and the electrical resistivity of the nanowire.

Simultaneous observation of acoustic resonance phenomena at both surfaces of a plate coated with thin layers.

Acoustic resonance phenomena at the front and back surfaces of a plate coated with thin layers were successfully observed in the amplitude spectrum of the back surface echo. The amplitude ratio of spectra with and without layers takes its maximum and minimum values at the resonant frequencies of the front and back coatings and both frequencies can clearly be distinguished from each other. As an application, the thicknesses of the front and back coatings on a steel plate were measured simultaneously using their resonant frequencies, thus verifying the validity of the principle.

Accurate determination of the structural elasticity of human hair by a small-scale bending test.

This paper reports on a small-scale bending method for human hair. The test sample, which is elliptical in cross-section, is fixed to a hollow steel needle using resin to form a cantilever. A loading probe is used to subject this to a lateral load, where the load is applied parallel to either the long or short axis of the elliptical cross-section.

Sensitivity of acoustic microscopy for detecting three-dimensional nanometer gaps embedded in a silicon structure.

The sensitivity of acoustic microscopy for detecting three-dimensional defects in a Si structure is reported. Circular, nanometer gaps with diameters ranging from 5 to 1000 microm were embedded in Si disks by a direct bonding technique, and these were visualized using acoustic microscopy. The limits of detection for the gap thickness and diameter were observed simultaneously in samples with gaps of 4 and 140 nm.

Fabrication of Al microspheres by utilizing electromigration.

Aluminum microspheres with diameters of 4-7 microm have been fabricated by utilizing electromigration. In a passivated Al line with a slit at the anode end, atoms accumulated before the slit due to high current density and high substrate temperature are released from the pre-introduced holes in the passivation layer, and form microspheres with aid of surface tension. The spheres are formed at the specific range of the temperature at the anode end of Al line.

Potential of acoustic imaging in the detection of nanometer gaps.

The potential of the water-immersion and dry-contact acoustic imaging techniques for detecting nanometer gaps embedded in silicon is studied. The sensitivity for detecting gaps of over 10 nm in height is governed only by the lateral resolution of the imaging and is independent of the height of the gap.

Design and performance of a thin, solid layer for high-resolution, dry-contact acoustic imaging.

Compared to the usual water immersion case, more effective transmission and reception of high-frequency ultrasound through a thin, solid layer are reported. A theoretical model is presented to perform the signal amplification and the signal modulation toward the higher frequency components for getting the high-quality acoustic images without immersing the object to be imaged. Also, the thin, solid layers are designed from the theoretical model, and the transmission of high-frequency ultrasound is carried out through the layer/silicon interfaces with an applied pressure of about 0.

Dry-contact technique for high-resolution ultrasonic imaging.

To accomplish a high-resolution ultrasonic imaging without wetting a sample, the efficiency of the dry-contact ultrasonic transmission is discussed. In this study, a dry-contact interface is formed on a sample by inserting a thin film between water and a sample, and the pressure is working on the interface by evacuating the air between the film and the sample. A model of dry-contact ultrasonic transmission is presented to assess the signal loss accompanied with the transmission.