This study presents the finite element analysis (FEA) on an arch-type piezoelectric film sensor which had previously been designed for unconstrained monitoring cardiorespiratory signals. Both ends of a flexible arch-shaped plastic sheet are fixed on both ends of piezoelectric film, which is shorter than the arc length of the arch-shaped plastic sheet. As a result, the structure behaves as force-conversion mechanism where pressure to perpendicular direction is converted into horizontal tension. The FEA suggested how the ratio of the arc length of the plastic sheet to the length of the piezoelectric film affects the sensitivity.
A simple deformable bimorphous mirror using the PMN electrostrictor has been made for refocusing a light beam. Parabolic deformation of the mirror has been measured by an interferometric technique on a cycle with rising and falling electric fields. In comparison with the hard PZT piezostrictor, the electrostrictor is found to be promising for practical mirror control applications because of a large strain with neither hysteresis nor aging effects.
In the scratch test, the most commonly used method for evaluating the adhesion of thin surface coatings, the coated surface is scratched by a conical diamond indenter as load is gradually increased to the critical value Lc, at which the coating fails. As local deformation and failure occur in the material, some of the energy stored in the coating is released as acoustic emission.This paper analyzed the acoustic emissions while scratch testing high-speed tool steel (SKH 51) that was TiN-coated by PVD method. It was found that acoustic emissions were detected as an event rate signal when cracking of the coating occured, and that the average amplitude of the signals suddenly increased when chipping or spalling failure occured. It was concluded that the analysis of the average amplitude of signals was an effective means of estimating Lc, the value of which depended on the thickness both of the TiN coating and of the Ti undercoating.
Adhesion of thin SiNx to a stainless steel SUS 310 substrate was done through use of an arc ion plating process. Film properties were investigated with structural analysis and adhesion to determine conditions for film deposition. For this process, the voltage of the substrate bias was -200V to -600V, the gas pressure in the plating chamber was 1.3×10-2∼6.7×10-2Pa, and gas formation was examined comparatively for 100% N2 and 50% N2/50% He. The substrate temperature remained constant at 580°C and electrode voltage was 50V.These films were evaluated in terms of critical load value (Lc) measured by a micro-scratch machine, X-ray diffraction patterns, and results of state analysis using an electron probe microanalizer (EPMA) and electron spectroscopy for chemical analysis (ESCA). The following conclusions were obtained. 1) A lower bias voltage is satisfactory, though an increase in the critical load leads to favorable adhesion. 2) A mixture of N2 and He in the chamber results in superior Lc for the deposited film. 3) The films have an amorphous mixture of Si3N4 and Si.
Cotton fabrics for the standard artificial soiling recommended by JOCS are used for the treatment under conventional industrial conditions. Their properties, however, are different markedly from lot to lot owing to the finishing conditions. Accordingly, authors investigated the quality change of the fabrics during oxidative bleaching by sodium hypochlolite solution. The change of copper number and average polymerization degree (fluidity), as well as the tensile and tear strength of bleached fabrics were determined.Results obtained are as follows : 1) With the increases in copper number and/or fluidity of oxidized cellulose, the fabrics become to be easily soiled and the artificially soiled fabrics are easily desoiled as well.2) Copper number and fluidity of oxidized cellulose are intimately related to the tear and tensile strength. Chemical damage of the fabrics caused by bleaching can also be detected from these measurements.The authors found a clue to control the bleaching condition in order to supply standard cotton fabrics of constant properties.
Error separation techniques of the surface profile from parasitic motions have been developed for the straightness profile measurement of a mechanical workpiece. These are known as software datums, which separate the surface profile from the parasitic motions by using multiple sensors and/or multiple orientations. The authors proposed a generalized twopoint method that used the difference with either integration or inverse filtering. This method can take any sampling interval. In this article, the relationship between the ratio of the sensor distance to the sampling interval and the error propagation at the lowest spatial frequency is clarified. Furthermore, experimental results are described to support the theoretical analysis of the error propagation.
In the straightness profile measurement of a mechanical workpiece, hardware datums have been the traditional standard. However, when the straightness profile is measured using a scanning displacement sensor set on an X-stage as the hardware datums, output of a displacement sensor includes the signal of straightness profile and the sensor’s parasitic motion, i.e. straightness error motion. Then, error separation techniques of the straightness profile from parasitic motions have been developed. For example, two-point method uses two displacement sensors and separates the sensor’s straightness error motion from the straightness profile. However, the conventional two-point method cannot measure a large-scale workpiece because the large sampling number causes random error amplification. In this article, the influence of the random error of generalized two-point method is shown. As the result of the theoretical analysis and numerical analysis, random error propagation decrease when sampling number increase. Further, experimental results obtained by generalized two-point method with large sampling number are analyzed using Wavelet transform and influence of error of the generalized two-point method is discussed in the space-spatial frequency domain.
After the possibility of penetration hardness measurements by using a nanoindenter was examined, the penetration hardness of silicon nitride thin films produced under various depositing conditions was measured. Adhesion of thin silicon nitride to a stainless steel of SUS310 substrate was done through use of an arc ion plating process. For this process, the voltage of the substrate bias was changed ranging from -200V to -600V, the gas pressure in the plating chamber was 1.3×10-2∼6.7×10-2Pa, and gas formation was examined comparatively for 100% N2 and mixed gas of 50% N2/50% He. The substrate temperature remained constant at 580°C and electrode voltage was 50V.The following conclusions were obtained. 1) A high pressure and a mixture of N2 and He in the chamber resulted in superior hardness for the deposited films. 2) The maximum penetration hardness of the silicon nitride films was 45.0GPa. When converted into microvickers hardness, the maximum value became 2410.
